8-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(d)

OF THE SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of earliest event reported): November 7, 2022

Marinus Pharmaceuticals, Inc.

(Exact name of registrant as specified in its charter)

Delaware	001-36576	20-0198082
(State or other jurisdiction of incorporation)	(Commission File Number)	(IRS Employer Identification No.)

, Radnor, PA
5 Radnor Corporate Center, Suite 500 100 Matsonford Rd, Radnor, PA	19087
(Address of principal executive offices)	(Zip Code)

Registrant’s telephone number, including area code: (484) 801-4670

__________________________________________________________________
(Former name or former address, if changed since last report.)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐	Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)
☐	Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)
☐	Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))
☐	Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class	Trading Symbol(s)	Name of each exchange on which registered
Common Stock, par value $0.001	MRNS	Nasdaq Global Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company  ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.  ☐

Item 2.02. Results of Operations and Financial Condition.

On November 7, 2022, Marinus Pharmaceuticals, Inc. (the “Company”) issued a press release announcing its financial results for the quarter ended September 30, 2022 and certain other information. A copy of the press release is being furnished as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated by reference to this Item 2.02.

The information furnished pursuant to this Item 2.02 shall not be deemed to be “filed” for purposes of Section 18 of the Securities Exchange Act of 1934 (the “Exchange Act”) or otherwise subject to the liabilities of that section, nor shall it be deemed to be incorporated by reference into any of the Company’s filings with the Securities and Exchange Commission under the Exchange Act or the Securities Act of 1933, whether made before or after the date hereof, regardless of any general incorporation language in such a filing, except as expressly set forth by specific reference in such a filing. Except as required by law, we undertake no duty or obligation to publicly update or revise the information so furnished.

Item 8.01. Other Events.

On November 7, 2022, the Company posted the Third Quarter 2022 Corporate and Financial Update on its website at www.marinuspharma.com. A copy is filed as Exhibit 99.2 to this Current Report on Form 8-K and is incorporated by reference to this Item 8.01.

Item 9.01. Financial Statements and Exhibits.

(d)Exhibits

Exhibit No.	Description
99.1	Press Release, dated November 7, 2022, of Marinus Pharmaceuticals, Inc.
99.2	Corporate Presentation, Third Quarter 2022 Corporate and Financial Update, dated November 2022.
104	The cover page from this Current Report on Form 8-K, formatted in Inline XBRL.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

	MARINUS PHARMACEUTICALS, INC.
Date: November 7, 2022	/s/ Steven Pfanstiel
	Steven Pfanstiel
	Chief Financial Officer and Treasurer

EX-99.1

Exhibit 99.1

Marinus Pharmaceuticals Provides Business Update and Reports Third Quarter 2022 Financial Results

● Initiated U.S. ZTALMY^® (ganaxolone) launch in late July with over 50 completed CDKL5 deficiency disorder prescription enrollment forms; approximately 40% of those patients were on reimbursed therapy by the end of the third quarter

● ZTALMY generated $0.56 million in net product revenue for the first partial quarter following launch and received positive coverage criteria from over 15 payers representing approximately 70 million lives

● Actively recruiting Phase 3 clinical trials in refractory status epilepticus and tuberous sclerosis complex; data continues to be expected 2H 2023 and Q1 2024, respectively

● Cash runway projected to extend into Q1 2024 following sale of Priority Review Voucher, exercise of contract option by BARDA and execution of revenue interest financing agreement

● Marinus to host conference call on November 8, 2022, at 8:30 a.m. ET

RADNOR, Pa. – November 7, 2022 –Marinus Pharmaceuticals, Inc. (Nasdaq: MRNS), a pharmaceutical company dedicated to the development of innovative therapeutics to treat seizure disorders, today reported business highlights and financial results for the third quarter ended September 30, 2022.

“I’m incredibly proud of the progress the Marinus team has made to position the organization for success as we enter our next stage of growth as a commercial-stage company,” said Scott Braunstein, M.D., Chief Executive Officer of Marinus. “The strong U.S. launch of ZTALMY coupled with two important recent transactions—the sale of the priority review voucher and the revenue interest financing—are projected to extend our cash runway into 2024 and allow us to continue to focus on executing beyond our two anticipated Phase 3 trial data readouts. We believe we are poised to execute on our goals and expand our reach to additional patients suffering from rare forms of epilepsy.”

ZTALMY^®

● Initiated U.S. commercial launch of ZTALMY^® (ganaxolone) oral suspension CV on July 28 with over 50 completed CDKL5 deficiency disorder (CDD) prescription enrollment forms from over 40 unique accounts for the nine-week launch period ended September 30

● Approximately 40% of CDD patients with completed prescription enrollment forms were on reimbursed therapy by the end of the third quarter, driving $0.56 million innet product revenue

● As of November 1, 2022, ZTALMY received favorable coverage determinations from over 15 payers representing approximately 70 million lives, with the remainder of published policies anticipated by year end

o 57% of U.S. commercial plans extended label coverage to ZTALMY

Clinical Pipeline

Status Epilepticus

Exhibit 99.1

● Protocol amendment for the Phase 3 RAISE trial of intravenous (IV) ganaxolone in refractory status epilepticus (RSE) adopted across the majority of clinical sites with full adoption expected by year end

o Targeting 70 total activated sites, including Canada and Australia, by Q2 2023

o Topline results continue to be expected in the second half of 2023

● Based on preliminary blinded review, baseline characteristics of patients currently enrolled in Phase 3 RSE trial are comparable to those who were enrolled in the Phase 2 RSE trial

● Phase 3 RAISE II trial in RSE (for European registration) protocol finalized with enrollment anticipated to begin in the second half of 2023

● Phase 2 RESET trial in established status epilepticus (ESE) site activations underway and expected to begin U.S. enrollment by year end

● Biomedical Advanced Research and Development Authority (BARDA), part of the Administration for Strategic Preparedness and Response at the U.S. Department of Health and Human Services, exercised its first contract option valued at approximately $12.3 million to support U.S. onshoring of the manufacturing capabilities for ganaxolone active pharmaceutical ingredient (API)

Ganaxolone development in the RAISE trial is being funded in part by the Biomedical Advanced Research and Development Authority (BARDA), part of the Administration for Strategic Preparedness and Response at the U.S. Department of Health and Human Services, under contract number 75A50120C00159.

Tuberous Sclerosis Complex (TSC)

● Actively screening patients in Phase 3 TrustTSC trial of oral ganaxolone at sites in the U.S. and Europe

● Targeting 85 clinical sites with activations in Canada and Israel expected by year end and Australia in the first half of 2023

● Topline data continues to be anticipated in the first quarter of 2024

CDKL5 Deficiency Disorder (CDD)

● On track to submit complete responses to the European Medicine Agency (EMA) Day 120 List of Questions for the Marketing Authorization Application (MAA) for ZTALMY by the end of November 2022, which would result in the EMA Committee for Medicinal Products for Human Use opinion by the end of the first quarter of 2023

Second Generation Product Development

● An additional Phase 1 cohort of a second generation oral formulation is planned

o An assessment of higher single doses above 900 mg in healthy volunteers

o Multiple ascending dose (MAD) study planned for 1H 2023

● Phase 2 trial in Lennox-Gastaut syndrome is targeted to begin in 2023

● Prodrug development continues to advance with lead oral and IV candidates selected; Phase 1 data targeted for 2024

Exhibit 99.1

Financial and Business Updates

● Closed on the sale of the Rare Pediatric Disease Priority Review Voucher for $110 million in August 2022

● In October 2022, Marinus entered into a revenue interest financing agreement with Sagard Healthcare Partners for a total of $32.5 million upfront in return for future payments on U.S. net sales of ganaxolone

● Expect that funding received as a result of the recently completed revenue interest financing in addition to cash and cash equivalents on hand as of September 30, 2022 will be sufficient to fund the Company’s operating expenses, capital expenditure requirements and maintain the minimum cash balance of $15 million required under the Company’s debt facility into the first quarter of 2024

Financial Results (preliminary)

● At September 30, 2022, the Company had cash and cash equivalents of $168.2 million, compared to $122.9 million at December 31, 2021.

● Marinus recognized $2.3 million and $18.3 million in total revenue for the three and nine months ended September 30, 2022, respectively, as compared to $10.1 million and $13.8 million, for the same periods in the prior year, respectively. Revenues are recognized as a result of U.S. product sales of ZTALMY, Marinus’ BARDA federal contract and European collaboration with Orion Corporation.

o Net product revenues of $0.56 million were recorded for each of the three and nine months ended September 30, 2022 as a result of the commercial launch of ZTALMY in late July 2022. No net products revenues were recorded in periods prior to the launch.

o The Company recognized $1.8 million and $5.1 million in BARDA federal contract revenue for the three and nine months ended September 30, 2022, respectively, as compared to $1.1 million and $4.8 million for the same periods in the prior year, respectively.

o Collaboration revenue in 2022 consists of a one-time revenue recognition of $12.7 million in the first quarter of 2022 related to the Orion collaboration. Collaboration revenue in the prior year of $9.0 million was recognized in the third quarter of 2021 as a result of the upfront payment from the Orion collaboration.

● Research and development (R&D) expenses were $19.0 million and $58.5 million for the three and nine months ended September 30, 2022, respectively, as compared to $18.4 million and $55.5 million for the same periods in the prior year, respectively. The increase was due primarily to costs associated with increased R&D headcount and start-up of the Phase 3 tuberous sclerosis complex trial, partially offset by reduced costs associated with the CDKL5 deficiency disorder (CDD) indication.

● Selling, general and administrative (SG&A) expenses were $13.4 million and $42.2 million for the three and nine months ended September 30, 2022, respectively, as compared to $9.5 million and $26.7 million for the same periods in the prior year, respectively. The primary drivers of the increase were preparation for and launch of ZTALMY and additional support for scale up of the Company’s operations.

Exhibit 99.1

● During the nine months ended September 30, 2022, a one-time IP license fee of $1.2 million was recognized as expense in the first quarter of 2022, associated with the agreement with Ovid Therapeutics to license patents and patent applications for the use of ganaxolone in the treatment of CDD.

● The Company reported net income of $73.3 million and $14.5 million for the three and nine months ended September 30, 2022, respectively. These net income totals include a one-time gain of $107.4 million associated with the sale of the PRV in the third quarter of 2022; cash used in operating activities increased to $91.0 million for the nine months ended September 30, 2022, compared to $33.7 million for the same period a year ago.

● Readers are referred to, and encouraged to read in its entirety, the Company’s Quarterly Report on Form 10-Q for the three months ended September 30, 2022, to be filed with the Securities and Exchange Commission, which includes further detail on the Company’s business plans, operations, financial condition, and results of operations.

Selected Financial Data (in thousands, except share and per share amounts)

	September 30,		December 31,
	2022		2021
ASSETS
Cash and cash equivalents	$	168,249	$	122,927
Other assets		16,592		13,913
Total assets	$	184,841	$	136,840
LIABILITIES AND STOCKHOLDERS’ EQUITY
Current liabilities	$	21,050	$	40,566
Long Term Debt, Net		70,780		40,809
Other long-term liabilities		11,007		1,979
Total liabilities		102,837		83,354
Total stockholders’ equity		82,004		53,486
Total liabilities and stockholders’ equity	$	184,841	$	136,840

	Three Months Ended September 30,				Nine Months Ended September 30,
	2022		2021		2022		2021
Revenue:
Product revenue, net	$	555	$	—	$	555	$	—
Federal contract revenue		1,785		1,127		5,088		4,838
Collaboration revenue		—		8,987		12,673		8,987
Total revenue		2,340		10,114		18,316		13,825
Expenses:
Research and development		19,002		18,353		58,488		55,506
Selling, general and administrative		13,389		9,452		42,187		26,656
Cost of product revenue		48		—		48		—
Cost of collaboration revenue		—		1,478		—		1,478

Exhibit 99.1

Cost of IP license fee		—			—			1,169			—
Total expenses:		32,439			29,283			101,892			83,640
Loss from operations		(30,099	)		(19,169	)		(83,576	)		(69,815	)
Interest income		514			17			610			57
Interest expense		(2,634	)		(678	)		(6,982	)		(1,029	)
Gain from sale of priority review voucher, net		107,375			—			107,375			—
Other income (expense), net		(114	)		323			(1,179	)		316
Income (loss) before income taxes		75,042			(19,507	)		16,248			(70,471	)
Provision for income taxes		(1,752	)		—			(1,752	)		—
Net income (loss) and comprehensive income (loss)	$	73,290		$	(19,507	)	$	14,496		$	(70,471	)
Net income (loss) applicable to common shareholders	$	71,634		$	(19,507	)	$	14,160		$	(70,471	)
Per share information:
Net income (loss) per share of common stock—basic	$	1.93		$	(0.53	)	$	0.38		$	(1.92	)
Net income (loss) per share of common stock—diluted	$	1.89		$	(0.53	)	$	0.37		$	(1.92	)
Basic weighted average shares outstanding		37,202,269			36,744,591			37,084,060			36,667,472
Diluted weighted average shares outstanding		37,910,511			36,744,591			38,393,754			36,667,472

Conference Call Information

Tuesday, November 8, at 8:30 a.m. ET

Domestic: (888) 550-5280

International: (646) 960-0813

Webcast Link:  https://events.q4inc.com/attendee/163157006

Conference ID: 2696394

About Marinus Pharmaceuticals

Marinus is a commercial-stage pharmaceutical company dedicated to the development of innovative therapeutics for seizure disorders. The Company’s commercial product, ZTALMY^® (ganaxolone) oral suspension CV, has been approved by the U.S. FDA for the treatment of seizures associated with CDKL5 deficiency disorder in patients two years of age and older. The potential of ganaxolone is also being studied in other seizure disorders, including in Phase 3 trials in tuberous sclerosis complex and refractory status epilepticus. Ganaxolone is a neuroactive steroid GABA_A receptor modulator that acts on a well-characterized target in the brain known to have anti-seizure effects. It is being developed in IV and oral formulations to maximize therapeutic reach for adult and pediatric patients in acute and chronic care settings. For more information visit www.marinuspharma.com.

Forward-Looking Statements

Exhibit 99.1

To the extent that statements contained in this press release are not descriptions of historical facts regarding Marinus, they are forward-looking statements reflecting the current beliefs and expectations of management made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Words such as "may", "will", "expect", "anticipate", "estimate", "intend", "believe", and similar expressions (as well as other words or expressions referencing future events, conditions or circumstances) are intended to identify forward-looking statements. Examples of forward-looking statements contained in this press release include, among others, statements regarding our commercialization and marketing plans for ZTALMY; the potential benefits ZTALMY will provide for physicians and patients; our expectations regarding the ZTALMY One program; statements regarding our expected clinical development plans, enrollment in our clinical trials, regulatory communications and submissions for ganaxolone, and the timing thereof; our plans with respect to the use of the proceeds from the PRV sale and the Sagard agreement; our expected cash runway; our expectations regarding BARDA funding; our expectations and beliefs regarding the FDA and EMA with respect to our product candidates; our expectations regarding the development of new formulations and prodrug candidates; our expectation regarding the impact of the COVID-19 pandemic on our business and clinical development plans; our financial projections; the potential safety and efficacy of ganaxolone, as well as its therapeutic potential in a number of indications; and other statements regarding the company's future operations, financial performance, financial position, prospects, objectives and other future event.

Forward-looking statements in this press release involve substantial risks and uncertainties that could cause our clinical development programs, future results, performance or achievements to differ significantly from those expressed or implied by the forward-looking statements. Such risks and uncertainties include, among others, unexpected results or delays in the commercial launch of ZTALMY, including any potential delays caused by the current COVID-19 global pandemic; unexpected market acceptance, payor coverage or future prescriptions and revenue generated by ZTALMY; unexpected actions by the FDA or other regulatory agencies with respect to our products; competitive conditions and unexpected adverse events or patient outcomes from being treated with ZTALMY, uncertainties and delays relating to the design, enrollment, completion, and results of clinical trials; unanticipated costs and expenses; the varying interpretation of clinical data; our ability to comply with the FDA’s requirement for additional post-marketing studies in the required time frames; the timing of regulatory filings for our other product candidates; the potential that regulatory authorities, including the FDA and EMA, may not grant or may delay approval for our product candidates; early clinical trials may not be indicative of the results in later clinical trials; clinical trial results may not support regulatory approval or further development in a specified indication or at all; actions or advice of the FDA or EMA may affect the design, initiation, timing, continuation and/or progress of clinical trials or result in the need for additional clinical trials; our ability to obtain and maintain regulatory approval for our product candidate; our ability to develop new formulations of ganaxolone or prodrugs; our ability to obtain, maintain, protect and defend intellectual property for our product candidates; the potential negative impact of third party patents on our or our collaborators’ ability to commercialize ganaxolone; delays, interruptions or failures in the manufacture and supply of our product candidate; the size and growth potential of the markets for the company’s product candidates, and the company’s ability to service those markets; the company’s cash and cash equivalents may not be sufficient to support its operating plan for as long as anticipated; the company’s expectations, projections and estimates regarding expenses, future revenue, capital requirements, and the availability of and the need for additional financing; the company’s ability to obtain additional funding to support its clinical development

Exhibit 99.1

and commercial programs; the potential for our ex-US partners to breach their obligations under their respective agreements with us or terminate such agreements in accordance with their respective terms; the risk that drug product quality requirements may not support continued clinical investigation of our product candidates and result in delays or termination of such clinical studies and product approvals; the effect of the COVID-19 pandemic on our business, the medical community, regulators and the global economy; and the availability or potential availability of alternative products or treatments for conditions targeted by us that could affect the availability or commercial potential of our product candidate. This list is not exhaustive and these and other risks are described in our periodic reports, including the annual report on Form 10-K, quarterly reports on Form 10-Q and current reports on Form 8-K, filed with or furnished to the Securities and Exchange Commission and available atwww.sec.gov. Any forward-looking statements that we make in this press release speak only as of the date of this press release. We assume no obligation to update forward-looking statements whether as a result of new information, future events or otherwise, after the date of this press release.

Company ContactSasha Damouni EllisVice President, Corporate Affairs & Investor RelationsMarinus Pharmaceuticals, Inc.sdamouni@marinuspharma.com

EX-99.2

Exhibit 99.2

Nasdaq: MRNS @MarinusPharma Photo Credit: Kelly Crews Photography Ryan (center) Living with CDKL5 deficiency disorder Third Quarter 2022 Corporate and Financial Update November 2022

©2022 Marinus Pharmaceuticals. All Rights Reserved I To the extent that statements contained in this presentation are not descriptions of historical facts regarding Marinus, they ar e forward - looking statements reflecting the current beliefs and expectations of management made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 19 95. Words such as “may”, “will”, “expect”, “anticipate”, “estimate”, “intend”, “believe”, and similar expressions (as well as other words or expressions referencing future events, co ndi tions or circumstances) are intended to identify forward - looking statements. Examples of forward - looking statements contained in this presentation include, among others, statements rega rding our expected revenue and operating expenses for 2022; our commercialization plans for ZTALMY® and clinical development plans for ganaxolone and the expected timing thereof ; our anticipated and potential financing plans; expected dosing in our clinical trials; the clinical development schedule and milestones; our expected timing to begin and complete en rol lment in our clinical trials; the expected trial design, target patient population and endpoints for our clinical trials; interpretation of scientific basis for ganaxolone use; timing for a vai lability and release of data; the potential safety and efficacy and therapeutic potential of ganaxolone; timing and expectations regarding the potential benefits ZTALMY will provide for patient s a nd physicians , our expectations regarding the ZTALMY One program; timing and expectations regarding regulatory communications and submissions; expectations regarding our agreement with BARDA; expectations regarding our collab ora tion with Orion C orporation ; expectations regarding the potential market opportunities for our product candidates, including oral ganaxolone; potential com mercial alliances; and our expectations regarding the effect of the COVID - 19 pandemic on our business and clinical development plans. Forward - looking state ments in this presentation involve substantial risks and uncertainties that could cause our clinical development programs, future results, performance or achievements to differ signi fic antly from those expressed or implied by the forward - looking statements. Such risks and uncertainties include, among others, uncertainties and delays relating to our ability to e sta blish commercial infrastructure and capabilities to deliver commercial supply of ZTALMY, patient and physician acceptance of ZTALMY, our ability to obtain adequate market access for ZTA LMY ; our ability to comply with the FDA’s requirement for additional post - market studies in the required timeframes; the timing of regulatory filings, including the timing of filing the ganaxolone MAA with the EMA; the potential that regulatory authorities, including the FDA and EMA, may not grant or may delay approval for our product candidates; uncertainties and del ays relating to the design, enrollment, completion, and results of clinical trials; unanticipated costs and expenses; early clinical trials may not be indicative of the results in l ate r clinical trials; clinical trial results may not support regulatory approval or further development in a specified indication or at all; actions or advice of the FDA or EMA may affect the desig n, initiation, timing, continuation and/or progress of clinical trials or result in the need for additional clinical trials; our ability to obtain and maintain regulatory approval for our product can didates; our ability to obtain, maintain, protect and defend intellectual property for our product candidates; the potential negative impact of third party patents on our or our collabor ato rs’ ability to commercialize ganaxolone; delays, interruptions or failures in the manufacture and supply of our product candidates; the size and growth potential of the markets for our pro duc t candidates, and our ability to service those markets; our cash and cash equivalents may not be sufficient to support our operating plan for as long as anticipated; our expectations, p roj ections and estimates regarding expenses, future revenue, capital requirements, and the availability of and the need for additional financing; our ability to obtain additional funding to support our commercial and clinical development programs; the potential for Orion Corporation to breach our collaboration agreement or terminate the agreement in accordance with its t erm s; the effect of the COVID - 19 pandemic on our business, the medical community, regulators and the global economy; and the availability or potential availability of alternative produ cts or treatments for conditions targeted by us that could affect the availability or commercial potential of our product candidates. Marinus undertakes no obligation to update or revi se any forward - looking statements. For a further description of the risks and uncertainties that could cause actual results to differ from those expressed in these forward - looking statements, as well as risks relating to our business in general, see filings we have made with the Securities and Exchange Commission. You may access these documents for free by visiting EDGAR on the SE C w eb site at www.sec.gov. Safe Harbor Statement 2

©2022 Marinus Pharmaceuticals. All Rights Reserved I Ganaxolone Development Pipeline 3 PDUFA date March 2022 MAA filing validation Q4 2021 Ph3 patient enrollment Q1 2022 Topline data 1H 2024 GANAXOLONE Phase 1 Phase 2 Phase 3 Approved Oral Suspension Intravenous Intravenous Intravenous Oral Suspension (Second Gen. Formulation) Administered Seizure Disorders Oral Suspension CDKL5 Deficiency Disorder Marigold Study FDA approved Topline data 2H 2023 Enroll first patient 2H 2023 Enroll first patient 2H 2022 Data year end 2023 Phase 1, high dose cohort data 1H 2023 Topline data Q1 2024 Ongoing trial Planned future trial Preclinical Lennox - Gastaut Syndrome Anticipated Milestones EU CHMP opinion Q1 2023 Refractory Status Epilepticus RAISE Trial Tuberous Sclerosis Complex TrustTSC Trial Established Status Epilepticus RESET Trial Second Generation Formulation Refractory Status Epilepticus RAISE II Trial Ganaxolone is a positive allosteric GABA A receptor modulator with a well - defined MOA designed to treat patients suffering from seizure disorders. Ganaxolone is designed to modulate both synaptic and extrasynaptic GABA A receptors to calm over - excited neurons.

©2022 Marinus Pharmaceuticals. All Rights Reserved I 4 ¹ Symonds JD 2019 Brain ² Curatolo P, Bombardieri R, Jozwiak S. Tuberous sclerosis. Lancet. 2008;372:657 – 68. ³DeLorenzo RJ et al. J Clin Neurophysiol .. 1995; 12: 316 - 325 4 Kapur et al. N Engl J Med 2019;381:2103 - 13 5 Rossetti and Lowenstein. Lancet Neurol. 2011 Oct; 10(10): 922 – 930 6 Trevathan et al. (1997). Epilepsia , 38(12), 1283 – 1288 Ganaxolone U.S. Market Opportunity Oral Ganaxolone Intravenous (IV) Ganaxolone Second Generation Product Development Stage Incidence / Prevalence Seizure type(s) Indication CDKL5 deficiency disorder Tuberous sclerosis complex FDA approved for seizures associated with CDD in patients 2 and older - Ph3 TrustTSC trial underway - Topline data anticipated Q1 2024 - 1:40,000 live births ¹ - 90 - 100 U.S. newborns / year - 1:6,000 live births 2 - 25 - 40k refractory U.S. patients Generalized and focal seizures Focal seizures (primarily) Refractory status epilepticus Established status epilepticus - Ph3 RAISE trial underway - Topline data anticipated 2H 2023 - Ph3 RAISE II trial for European registration expected to initiate 2H 2023 - Ph2 first patient enrolled planned 2H 2022 - Data anticipated year end 2023 (multiple dose finding cohorts) 35k U.S. patients / year 3,5 75k patients / year 3,4 Continuous/persistent electrographic or clinical seizures Lennox - Gastaut syndrome - Phase 1, high dose cohort data anticipated 1H 2023 - 26:100,000 people 6 - 48k U.S. patients - Drop seizures (atonic, tonic, or tonic - clonic ) - 90% intractable COMMERCIAL PIPELINE PIPELINE PIPELINE Not for promotional use

ZTALMY ® (ganaxolone) oral suspension CV Marigold Clinical Data & Commercial Launch Not for promotional use

©2022 Marinus Pharmaceuticals. All Rights Reserved I 6 Ganaxolone Placebo 0 10 20 30 40 Median Percent Reduction 28-day Frequency of Major Motor Seizures 30.7% 6.9% *Wilcoxon Rank-Sum Test **Hodges-Lehman Estimate of Median Difference Patients taking ganaxolone experienced a significant reduction in seizure frequency G anaxolone reduced the frequency of monthly major motor seizures by a median of 30.7% compared with 6.9% for placebo (p=0.0036)* Δ = 27.1% (47.9 - 9.6)* * *Hodges - Lehmann estimate of median difference (95% confidence interval); **Wilcoxon rank - sum test Data as of July 22, 2021 1. Pestana - Knight EM, et al. Lancet Neurol. 2022;21(5):417 - 427. 2. Data on file. Reduction in monthly major motor seizure frequency over 24 months in OLE ► At the time of the analysis, 54 patients (61.4%) were still in the OLE study ► Median percent reductions in MMSF from baseline ranged 25% to 42% during initial 12 months and was between 44% and 56% through 24 months in the OLE phase • Open - label design and small sample size preclude efficacy conclusions from being drawn ► No new safety findings emerged in the OLE preliminary analysis and adverse reactions were consistent with the double - blind phase 1 Seizure reductions were observed in OLE patients Phase 3 Marigold data published in The Lancet Neurology First international CDKL5 guidelines published in Frontiers in Neurology Phase 3 Marigold Trial and Open Label Extension Data Not for promotional use

©2022 Marinus Pharmaceuticals. All Rights Reserved I Progress Indicators Following July 28 Commercial Launch 7 More than 50 prescription enrollment forms received for patients with CDD Over 30 new commercial patient enrollments Demand coming from over 40 unique accounts Positive coverage criteria from over 15 payers representing 70 million lives and 57% of U.S. commercial payer plans extended coverage to label as of Nov. 1 Payers reimbursed ~40% of CDD prescriptions as of Q3 Early published coverage criteria matching FDA - approved ZTALMY label Supported by increasing usage of ICD - 10 code Marigold data published in The Lancet Neurology First international CDKL5 guidelines published in Frontiers in Neurology 16 sales reps targeting 265 key hospitals and centers, including 8 CDD Centers of Excellence and 40 National Epilepsy Centers Continued engagement with key CDD advocacy groups and research organizations Signs of Early Demand in Q3 (first 9 weeks of launch) Payer Access Momentum Patient & HCP Education Not for promotional use

©2022 Marinus Pharmaceuticals. All Rights Reserved I ZTALMY U.S. Market Opportunity & Key Accounts 8 ~2,000 Addressable Pediatric Patients * Several data points suggest additional market opportunity in adult population 1 Symonds JD 2019 Brain *Estimated based on Symonds JD 2019 Brain • 8 CDD Centers of Excellence & 40 National Association of Epilepsy Centers • Genetic testing/screening widely used and available for early diagnoses • Usage of ICD - 10 code continues to increase • Insights from key advocacy groups Refractory to current treatments Target patient population: ages 2 - 21 with seizures 1 in 40,000 live births have CDKL5 Deficiency Disorder 1 Factors that support addressable patient population: 8 CDD ‘A’ Accounts (40) • National Association of Epilepsy Centers • Largest # of patient claims • Early adopters • High influence CDD ‘B’ Accounts (47) • Large # of patient claims • Delayed adoption • High influence CDD ‘C’ Accounts (178) • Medium # of patient claims • Adoption of new therapies • Require targeted commercial effort CDD Centers of Excellence (8) • Included for in A & B accounts • Sponsored by International Foundation for CDKL5 • Coordinated multi - specialty effort to address entirety of burden of disease Sales Lead, 2 Area Directors, 16 Field Representatives Market Access Team, 2 Area Directors, 1 Director Government Access, Channel Strategy & Operations Targeted & Scalable Commercial Structure Not for promotional use

Rare Epilepsies Oral Ganaxolone Pipeline

Tuberous Sclerosis Complex “Many individuals with TSC continue to experience uncontrolled seizures despite a cocktail of multiple antiepileptic drugs. Because new options are always needed, the TSC community welcomes clinical evaluation of new epilepsy treatments” - Kari Luther Rosbeck, President & CEO of the Tuberous Sclerosis Alliance

©2022 Marinus Pharmaceuticals. All Rights Reserved I 11 Tuberous Sclerosis Complex (TSC) 1 diMichele, et al, J. Neuro Neurosurg Psychiatry, 2003 *Failure of two prior antiseizure medications with ongoing, frequent seizures. CAUSE • Defect or mutation of TSC1 and/or TSC2 genes SYMPTOMS • Benign tumors, seizures, cognitive impairment, behavioral difficulties, skin abnormalities INCIDENCE PREVALENCE • 1:6,000 live births • ~25K - 40K refractory TSC patients in the U.S.* TREATMENTS • Despite available treatments, continued unmet medical need MECHANISTIC RATIONALE • Potential neurosteroid deficiency 1 • Pathophysiology may involve GABAergic dysfunction

©2022 Marinus Pharmaceuticals. All Rights Reserved I TSC Phase 2 Trial Results 12 * -200 -100 -80 -60 -40 -20 0 20 40 60 80 100 Percent reduction in TSC-associated seizure frequency =median 16.6% Secondary and Exploratory Analyses Primary Endpoint Results: 16.6% median reduction in TSC - associated seizures Ganaxolone was generally well - tolerated with somnolence, sedation and fatigue reported as the most common adverse events; in addition, one treatment - related serious adverse event of seizure was reported in the trial * Secondary endpoint Proportion of patients with a ≥50% reduction in TSC - associated seizure frequency Intent to Treat (n=23) +Cannabidiol (n=12) +Everolimus (n=11) 0 5 10 15 20 25 30 35 40 45 50 36.4 25.0 30.4 Percent of patients % % % Subjects with Focal Seizure Types (n=19) 0 10 20 30 25.2 Percent reduction in focal seizure frequency (median) %

©2022 Marinus Pharmaceuticals. All Rights Reserved I Phase 3 Protocol Refinements Informed by Phase 2 13 Phase 3 Slower titration initially, designed to optimize tolerability and improve efficacy 0 7 14 21 28 35 0 20 40 60 80 100 Time (days) Approx. % Max GNX Dose TSC Ph2 Titration TSC Ph3 Titration No (n=6) Yes (n=17) 0 5 10 15 20 25 30 Somnolence-related AE Percent reduction in TSC-associated seizure frequency (median) Phase 2 Patients without somnolence related AEs experienced directionally better seizure reductions

©2022 Marinus Pharmaceuticals. All Rights Reserved I Phase 3 Trial Overview 14 ► Enrollment: ~162 patients, targeting 85 sites in the U.S., Western Europe, Canada, Israel and Australia ► Primary Endpoint: Percent change in 28 - day TSC - associated seizure frequency ► Key Secondary Endpoints: Percent change in TSC - associated seizure frequency during 12 - week maintenance period, 50% responder rate, and clinical global impression ► FDA has indicated a single pivotal TSC Phase 3 trial could be sufficient for approval Ganaxolone Placebo Baseline (4 weeks) Titration (28 days) Maintenance (12 weeks) Eligible Patients with TSC R 1:1 Primary Endpoint Analysis Open - label Ganaxolone Double - blind Phase

Second Generation Product Development

©2022 Marinus Pharmaceuticals. All Rights Reserved I Second Generation Formulation 16 Strategic Objectives Enhanced Efficacy Achieve target blood levels to drive better clinical response Improved Safety Profile Optimize PK to mitigate somnolence levels Reduced Dosing Frequency More sustained serum levels to reduce dosing frequency Lowered COGS Better absorption to reduce API requirements per dose Enhanced IP Protection New IP associated with second generation formulation Expanded Indication Improved PK could address new areas of unmet need Expected Next Steps • Additional Phase 1 studies, including an assessment of higher single doses above 900 mg in healthy volunteers • Prodrug Phase 1 data targeted for 2024 Prodrug Opportunity Improve Product Profile Applicability to Both Oral and IV New Composition of Matter IP Protection Flexibility for IV Franchise

©2022 Marinus Pharmaceuticals. All Rights Reserved I Second Generation Oral Ganaxolone Rationale and Phase 1 Overview 17 Cohort 1 / 2 Treatment Six crossover treatment periods separated by 4 - day washout SCREENING Day - 1 thru – 28d Day 1 - Day 25 FOLLOW UP CALL Day 32 +/ - 2d Cohort 1 / 2 (n=6) Phase I Design Design Overview • Phase 1 open - label, 2 - cohort crossover study • Will evaluate several doses of the new formulation and compare the pharmacokinetics to the current formulation • To enroll twelve healthy male and female volunteers balanced across two cohorts End Points • PK comparison endpoints are C max , T max and AUC 0 - t Target PK Parameters • Increase absorption to achieve target exposure (AUC) • Increase the proportion of time plasma concentration exceeds the nominal minimally effective concentration (MEC) • Avoid significant increase in peak concentration ( C max ) Current Target Illustrative PK profiles. Prolonged duration of action

©2022 Marinus Pharmaceuticals. All Rights Reserved I Ganaxolone Second - Generation Oral Formulation 18 However, AUC increases linearly throughout the range of doses administered *Data on file. Studies 1042 - 0402 and 1042 - 0404, 7 - day multiple ascending dose studies with ganaxolone capsule formulation These preliminary Phase 1 results support testing PK at higher doses, which may support less frequent twice - daily dosing and an increase in overall exposure without compromising tolerability Dose - to - dose increase in C max reduced at higher doses ∆ = 18% ∆ = 37%

©2022 Marinus Pharmaceuticals. All Rights Reserved I Development plan goals • Efficiently select next generation product for clinical development in LGS and other potential indications • Proceed with targeted investments in parallel formulation and prodrug development to accelerate entry to Phase 2/3 • Ensure data related to PK, PD and CMC is sufficient to inform decisions to enter and advance clinical development Pathways to a Novel Oral Formulation for Lennox - Gastaut Syndrome Phase 2A LGS Key Decision Point: Selection of optimal LGS development candidate: prodrug or next generation ganaxolone formulation Reformulation Candidates Final decision for Phase 2b & 3 will be driven by pharmacokinetics, safety / tolerability, dosing schedule, IP and COGS Preclinical PK Candidate 1 Preclinical PK Candidate 2 Prodrug Candidates >150 synthesized Screening IND enabling studies Preclinical PK SAD MAD Phase 3 LGS SAD Phase 2B LGS = Decision point SAD: single - ascending dose MAD: multiple - ascending dose Reformulation Prodrug 19 MAD

Acute Seizure Disorders Intravenous (IV) Ganaxolone Pipeline

Status Epilepticus

©2022 Marinus Pharmaceuticals. All Rights Reserved I Status Epilepticus (SE): Definition and Epidemiology 22 SE is the second most common neurologic emergency in the U.S. 1 150,000 cases per year 2 1. Anesthesia and Intensive Care Medicine, February 02, 2018 , Update on the management of status epilepticus 2. DeLorenzo RJ Pellock JM Towne AR Boggs JG. Epidemiology of status epilepticus. J Clin Neurophysiol .. 1995; 12: 316 - 325 Background Prolonged continuous or near - continuous seizures Heterogeneous patient population with etiologies that include brain tumors, stroke, encephalitis, drug intoxication, or alcohol withdrawal Pre - existing epilepsy in less than half of SE cases Status epilepticus can result in permanent neuronal damage and contribute to high morbidity and mortality Becomes more treatment refractory with progression

©2022 Marinus Pharmaceuticals. All Rights Reserved I 23 Pharmacokinetics/Pharmacodynamics Well Suited for Acute SE Treatment Experimental PK – plasma and brain 1 Brain and plasma concentration after ganaxolone 3 mg/kg IM in mice Human PD – EEG changes 2 EEG bispectral index in healthy volunteers following IV ganaxolone 1. Zolkowska D, Wu CY, Rogawski MA. Intramuscular allopregnanolone and ganaxolone in a mouse model of treatment‐resistant status epilepticus. Epilepsia. 2018 Oct;59:220 - 7. 2. Data on file, Marinus Pharmaceuticals, inc .. Human PK 2 Following 30 mg ganaxolone bolus (over 5 minutes): C max 1,240 ng/mL T max 0.08 hrs Ganaxolone activates the extrasynaptic GABA A receptor, is associated with high brain concentrations, and delivers a rapid onset of action.

©2022 Marinus Pharmaceuticals. All Rights Reserved I Strategic Approach to SE Clinical Development 24 1. DeLorenzo RJ Pellock JM Towne AR Boggs JG. Epidemiology of status epilepticus. J Clin Neurophysiol. 1995; 12: 316 - 325 2. Kapur et al. Randomized Trial of Three Anticonvulsant Medications for Status Epilepticus N Engl J Med 2019;381:2103 - 13. 3. Rossetti and Lowenstein. Management of refractory status epilepticus in adults Lancet Neurol. 2011 Oct; 10(10): 922 – 930 Benzodiazepine Administered (Medically induced Coma) Established Status Epilepticus (ESE) IV AEDs (antiepileptic drugs) IV Anesthetics Super Refractory Status Epilepticus (SRSE) Refractory Status Epilepticus (RSE) 1st Line Status Epilepticus 3rd Line 2nd Line 150,000 Pts/Year 1 75,000 Pts/Year 2 35,000 Pts/Year 3 10,000 Pts/Year 3

©2022 Marinus Pharmaceuticals. All Rights Reserved I Treatment Period Loading Dose Maintenance Taper 25 Phase 2 Refractory Status Epilepticus Trial (RSE) Design • Diagnosis of convulsive or non - convulsive SE • Failed at least one 2 nd line IV AED but had not progressed to 3 rd line IV anesthetics Bolus plus continuous infusion 2 - 4 day infusion 18 - hour taper Screening Post - treatment Follow - up 24 hour Weeks 2, 3, 4 SE Patients Cohort Dose of ganaxolone/day N Low 500mg/day 5 Medium 650mg/day 4 High 713mg/day 8 Goals of a new treatment Limitations of current treatments Endpoints • Rapid cessation • Maintenance of seizure control • Prevent progression to IV anesthetics • 1st line Benzodiazepines ineffective in 45% - 50%; limited by cardiovascular and respiratory side effects • 2nd line Ineffective in over 50% of established SE; further decreased response in refractory SE • 3rd line IV Anesthetics: high morbidity, mortality ~35%; increased duration of hospitalization and costs of care • Primary: Percent of patients who did not require escalation of treatment with IV anesthetic within the first 24 hours after ganaxolone initiation • Secondary: Additional efficacy, safety and tolerability 8 males, 9 females Mean age: 57 years old (range: 23 - 88) 17 patients enrolled

©2022 Marinus Pharmaceuticals. All Rights Reserved I 26 Phase 2 Trial Results Demonstrated Rapid Onset And Durability of Effect Data presented at AES 2019 AEDs – antiepileptic drugs Cohort No escalation to IV anesthetics within 24 hours from infusion initiation (Primary Endpoint) Status - free through 24 hours from infusion initiation (investigator determination) No escalation to additional IV AEDs or IV anesthetics for status relapse at any time through 24 hours after ganaxolone discontinuation No SE Relapse at anytime during the 4 - wk follow up period High (713 mg/day) (n=8) 100% (8 of 8) 88% (7 of 8) 100% (8 of 8) 100% (6 of 6) (1ET, 1 died) Medium (650 mg/day) (n=4) 100% (4 of 4) 100% (4 of 4) 75% (3 of 4) 67% (2 of 3) (1 ET) Low (500 mg/day) (n=5) 100% (5 of 5) 100% (5 of 5) 60% (3 of 5) 50% (1 of 2) (1 died) Immediate Prior AED Administered 4 Hours (mean) to ganaxolone treatment SE Cessation Occurred Rapidly in All Dose Groups (median = 5 minutes) Safety Summary: • 2 treatment emergent serious adverse events noted as severe sedation • 13 treatment emergent adverse events: 5 moderate (4 somnolence; 1 hypercarbia); 6 mild (2 hypotension, 2 somnolence, 1 urinar y r etention, 1 hypercarbia) Trial data published in Epilepsia

©2022 Marinus Pharmaceuticals. All Rights Reserved I 27 PK/PD Relationship and Rationale for Target Dose Modeled PK Curves for All Dose Groups High Dose Achieved Target Range ≥ 500 ng/mL for ~8 hours Only High Dose Provided Sustained Reduction (>80%) Throughout Entire Analysis Window Data presented at AES 2019 PK: Pharmacokinetics / PD: Pharmadynamic Seizure Burden Reduction Occurred Rapidly in All Dose Groups

©2022 Marinus Pharmaceuticals. All Rights Reserved I RAISE: Phase 3 Trial in Refractory Status Epilepticus 28 Ganaxolone development for RSE is being funded, in part, by the Biomedical Advanced Research and Development Authority (BARDA ), part of the Office of the Assistant Secretary for Preparedness and Response at the U.S. Department of Health and Human Servic es, under contract number 75A50120C00159. TRIAL DESIGN • Double - blind, randomized, placebo - controlled trial in 124 patients with RSE DOSING • 36 - hour infusion followed by a 12 - hour taper (48 - hour treatment) • Phase 2 dose paradigm and extends ganaxolone plasma exposure ≥ 500 ng/mL for 12 hours CO - PRIMARY ENDPOINTS • Proportion of participants with SE cessation within 30 minutes of trial drug initiation without medications for acute treatment of SE • Proportion of participants with no progression to IV anesthesia for 36 hours following trial drug initiation SECONDARY ENDPOINTS • No progression to IV anesthesia for 24 hours off trial drug (72 hours) • Time to SE cessation • Healthcare utilization metrics (e.g., length of stay, # of ICU days • Functional outcomes ANALYSIS • Sequential testing of primary followed by key secondary endpoints • Analysis plan allows for potential interim analysis at N=82 subjects SCREENING Dose Initiation (Time 0) Treatment Period Follow - up Period Weeks 1,2,3 & 4 Daily 48 - 120 hours Day 2 Hours 24 - 48 Hours 36 - 48 (taper) Daily Hours 0 - 24 Bolus dose Continuous Infusion Taper Treatment duration is 2 days (including a 12 - hour taper)

©2022 Marinus Pharmaceuticals. All Rights Reserved I Patient Demographics: RSE Phase 2 vs. Phase 3 29 * This is preliminary data is as of the end of Q3 2022 and may not be representative of demographics of patients upon full enrollment of the RAISE trial Ag e (mean range) Consented Subjects Dosed History of Epilepsy Seizure Burden (Standard Deviation) 56.9 (23 - 88) 55.6 (15 - 88) 53% 58% 81% 57% 61.4% (37) 44.6% (36) STESS (SE Severity Score - mean range) Etiology With Prominent Motor features 2.8 (0 - 6) 2.8 (0 - 6) 29% 22% Tumors Stroke/hemorrhage Traumatic brain injury Neurodegenerative disorder Alcohol withdrawal Illicit drug use Metabolic disturbance Infection Autoimmune disorder Tumors Stroke/hemorrhage Traumatic brain injury Alcohol withdrawal Infection Autoimmune disorder Medication noncompliance Tuberous sclerosis Open Label Phase 2 RSE Trial Phase 3 RSE Trial*

©2022 Marinus Pharmaceuticals. All Rights Reserved I RAISE Protocol Amended to Accelerate Enrollment 30 Original Protocol Amended Protocol Patients excluded IF SE would NOT warrant anesthesia for the next 24 hours IV anesthesia would likely be next treatment if study drug (ganaxolone or placebo) does not control SE Treatment of the current SE episode w/ IV anesthetics at adequate dose and duration to induce anesthesia IV anesthesia (any dose/any indication) for less than 18 hours* Benzodiazepine(s) and two or more second - line IV AEDs At least two or more treatments, either: 1. Benzodiazepine(s) + > 1 IV AED 2. > 2 IV AEDs At least 6 minutes of seizure activity in the 30 - minute period prior to study drug initiation (20% seizure burden) At least 6 minutes of seizure activity in any 30 minutes within one hour of study drug initiation Ceribell rapid EEG permitted for screening only Ceribell rapid EEG permitted for study qualification and determination of EEG cessation (1 st co - primary endpoint) < 35 < 40 Included midazolam, propofol, thiopental, pentobarbital, phenobarbital or ketamine Phenobarbital and ketamine removed from list of anesthetic agents *Patients with continuing seizures despite IV anesthesia are excluded Goal is to drive greater enrollment without reducing sensitivity of study outcomes Amended protocol more closely aligns with Phase 2 population and clinical workflow Protocol component EEG criteria EEG criteria Prior failed treatments Pre - treatment IV anesthesia Escalation of treatment EEG monitoring BMI IV anesthetic agents

©2022 Marinus Pharmaceuticals. All Rights Reserved I RESET: Phase 2 Trial in Established Status Epilepticus 31 1 Kapur et al. Randomized Trial of Three Anticonvulsant Medications for Status Epilepticus N Engl J Med 2019;381:2103 - 13. Key Trial points: • Patients with convulsive status epilepticus • New dosing paradigm • FDA has indicated alignment on overall study design • Exception From Informed Consent community engagement planning underway • Planned start in 2H 2022 Benzodiazepine Administered IV AEDs (antiepileptic drugs) IV Anesthetics (Medically induced Coma) Established Status Epilepticus (ESE) Super Refractory Status Epilepticus (SRSE) Refractory Status Epilepticus (RSE) 1st Line 2nd Line 3rd Line Status Epilepticus ICU Tertiary Center ICU Emergency Room Key Trial points: • Patients with convulsive status epilepticus • New dosing paradigm • Exception From Informed Consent community engagement underway • First patient enrolled expected by end of 2022 • Sequential subject cohorts will evaluate dose and duration of treatment

©2022 Marinus Pharmaceuticals. All Rights Reserved I RESET Trial Design in Established Status Epilepticus 32 Screening <30 min Enrollment Fail BZD IV ganaxolone infusion 1 IV ganaxolone infusion 3 SOC IV AED Convulsive SE (N=40) Ganaxolone bolus Ganaxolone bolus Ganaxolone bolus Seizures YES NO Seizures YES NO Seizures YES NO SOC Treatment Phase After each 5 - subject cohort, will evaluate: Bolus – safety (sedation) / efficacy within 30 min Infusion – safety (sedation) / efficacy during ganaxolone infusion Duration – efficacy after infusion has been completed IV ganaxolone infusion 2 Do se optimization phase followed by double - blind phase with selected regimen Dose Optimization Phase

©2022 Marinus Pharmaceuticals. All Rights Reserved I RAISE II: Phase 3 Trial in Refractory Status Epilepticus 33 1 Kapur et al. Randomized Trial of Three Anticonvulsant Medications for Status Epilepticus N Engl J Med 2019;381:2103 - 13. Benzodiazepine Administered IV AEDs (antiepileptic drugs) IV Anesthetics (Medically induced Coma) Established Status Epilepticus (ESE) Super Refractory Status Epilepticus (SRSE) Refractory Status Epilepticus (RSE) 1st Line 3rd Line Status Epilepticus 2nd Line ICU Tertiary Center ICU Emergency Room RAISE vs. RAISE II TARGET PATIENT POPULATION Failure of at least two or more treatments , either: Benzodiazepine(s) + > 1 IV AED OR > 2 IV AEDs (n=124) Failure of benzodiazepines and at least one IV AED’s (RSE) (n=70) COMPARATOR Ganaxolone vs. Placebo in patients receiving background standard of care Ganaxolone vs. Placebo with concurrent IV AED initiation PRIMARY ENDPOINT Co - primary endpoints : (1)SE cessation within 30 min (2) no escalation to IV anesthesia within 36 hrs Responder analysis: SE cessation within 30 min and no escalation of care within 36 hrs Trial Goals: • Support potential European approval in RSE • Potential indication expansion opportunity (relative to the RAISE trial population)

Building Commercial Infrastructure for Future IV Launches

©2022 Marinus Pharmaceuticals. All Rights Reserved I Clinical and Healthcare Costs Associated with RSE 35 Utilization and Cost Outcomes Metric Cohort 1 (≤ 1 IV AED) Cohort 2 (> 1 IV AED) Cohort 3 (≥ 1 IV anesthetic) All Unique RSE patient encounter, N (%) 14,694 (33.4) 10,140 (23.1) 19,154 (43.5) 43,988 (100) Hospital length of stay (LOS) (days) Mean* 4.7 7.2 12.0 8.4 Median* 3 4 8 5 ICU LOS (for ICU patients only) Mean* 2.7 3.1 6.6 5.4 Median* 2 2 4 3 Total hospital cost* ($USD) Mean* $11,532 $18,328 $41,858 $26,304 Median* $6,812 $10,592 $24,105 $13,201 * Indicates p<0.05 across all pairwise comparisons Source: Guterman EL 2021 JAMA Neurol. Ganaxolone may offer the potential to reduce hospital costs and length of stay Treatments that prevent progression to SRSE with its associated complications may reduce length of stay and hospital costs

©2022 Marinus Pharmaceuticals. All Rights Reserved I Differentiated Market Access Strategy to Ensure Success for IV Ganaxolone Formulation 36 (DRG), diagnosis - related group reimbursement PRICING & REIMBURSEMENT • U.S./EU Pricing research initiated and ongoing • Determining New Technology Add - on Payment (NTAP) timing • Evaluating DRGs and other hospital payment systems DELIVERY & PATIENT ACCESS • Aligning on distribution pathway • Building plan for RSE and evaluating impact of ESE expansion VALUE PROPOSITION & HEALTH ECONOMIC MESSAGING • Assessing current treatment protocols • Evaluating burden of illness and hospital impact to expand & include cost avoidance metric CUSTOMER ENGAGEMENT • Considering impact of hospital networks to payer team • Ongoing assessment of potential hospital target segmentation underway

Financial Update

©2022 Marinus Pharmaceuticals. All Rights Reserved I Financial Overview: Q3 2022 38 Analyst Coverage*: Cantor Fitzgerald: Charles C. Duncan, Ph.D. Cowen: Joseph Thome, Ph.D. H.C. Wainwright & Co: Douglas Tsao Jefferies: Andrew Tsai JMP Securities: Jason N. Butler, Ph.D. Ladenburg Thalmann : Michael Higgins SVB Securities: Marc Goodman Oppenheimer: Jay Olson RW Baird: Brian Skorney Truist : Joon Lee, M.D., Ph.D. *Note: Opinions, estimates, and forecasts of the individual analysts regarding Marinus do not represent opinions, estimates, and forecasts of Marinus. The listing above does not imply endorsement or concurrent with their information, conclusions, or recommendations. 1 Fully dilutive total includes impact of convertible preferred stock and outstanding stock options and RSU’s Investor Relations – Nasdaq: MRNS 2022 Guidance • BARDA Revenues • FY 2022 projected to be between $7 - $10 million • Operating Expenses • FY 2022 GAAP operating expenses (SG&A and R&D) of between $150 - $155 million • Total includes approximately $15 million of non - cash stock - based compensation Financial Summary (at September 30 , 2022 ): • $ 168.2 million in cash and cash equivalents • $ 75 million in debt • 37.2 million shares outstanding; 44.6 million shares outstanding on a fully dilutive basis 1 $32.5 million in gross proceeds received in October 2022 from completed revenue interest financing agreement

©2022 Marinus Pharmaceuticals. All Rights Reserved I Liquidity Overview 39 Note: All values shown ar e gross transactional proceeds 1 Marinus potential to draw subject to achievement of certain clinical and financial milestones Financial Summary (as of September 30 , 2022) : • $168.2 million in cash and cash equivalents • Additionally, $32.5 million in gross proceeds received in October 2022 from revenue interest financing agreement with Sagard • $ 75 million in debt from Oaktree Capital agreement; interest - only through May 2024, matures 2026 Completed & Potential Non - Dilutive Funding Options : FDA Approval March 2022 Q1 2022 $30 million Oaktree Capital Credit Funding - Drawn March ’22 based upon FDA CDD approval Q3 2022 $110 million Sale of PRV - Completed August ‘22 Q4 2022 $32.5 million U.S. revenue interest financing - Completed October ‘22 Ongoing R&D Reimbursement: BARDA and Orion Corporation Q1 2022 Additional credit available under Oaktree Capital facility - Potential to draw $25 million of additional funding 1 Orion Corporation Potential Milestones & Royalties

©2022 Marinus Pharmaceuticals. All Rights Reserved I U.S. Revenue Interest Financing 40 U. S. revenue interest financing agreement with Sagard Healthcare Partners ( Sagard ) , a multi - strategy alternative asset manager, including healthcare royalties, with more than US$14 billion under management Marinus received payment of $32.5 million in exchange for ongoing payments on U.S. product revenue of Ztalmy ® and other products that contain ganaxolone Sagard to receive payments of 7.5% of net revenue of ganaxolone products through June 2026 ; increasing to 15% after that for the first $100 million of net revenue annually, decreasing to 7.5% of net revenue greater than $100 million annually Total payments have a cap of 1.9x the upfront investment of $32.5 million; Marinus option to buy - out at 1.6x within first 3 years and at 1.8x in the fourth year Transaction proceeds enable continued investment in commercialization, R&D, and manufacturing scale up *Availability subject to achievement of certain clinical and financial milestones Morgan Stanley & Co. LLC acted as lead placement agent and H. C. Wainwright & Co. acted as co - placement agent on the transaction Minimum total payment of 1.0x from Marinus to Sagard required by December 31, 2027; full repayment of 1.9x required by December 31, 2032

Intellectual Property

©2022 Marinus Pharmaceuticals. All Rights Reserved I Multiple Layers Of Potential Protection 42 Orphan drug designations for CDD and PCDH19 provide 7 and 10 years regulatory exclusivity in U.S. and EU, respectively. Orphan drug designation for SE provides 7 years regulatory exclusivity in U.S. Patents/ Patent Applications Expiration Date Status Epilepticus Method of Use Applications pending on potential dosing regimens for SRSE and ESE 2041/2042 U.S. patent granted on clinical regimen, applications pending in other jurisdictions 2040 Formulation Licensed Captisol ® patents Through 2033 Applications pending on IV formulation 2036 CDKL5 Deficiency Disorder Method of Use Patents granted in U.S. and Europe (oral suspension) 2031 (if PTE granted) Licensed patent granted in U.S. for treatment of epileptic disorders 2037 Application pending on potential dosing regimen 2038/2041/2042 Formulation Patents granted in U.S. and Europe (oral suspension) 2031 (if PTE granted) Tuberous Sclerosis Complex Method of Use Application pending on potential dosing regimen 2040/2041/2042 Formulation Patents granted in U.S. and Europe (oral suspension) 2031 (if PTE granted) Second Generation Ganaxolone Formulation Application pending on potential second generation formulations 2042/2043

XML

Document and Entity Information	Nov. 07, 2022
Document and Entity Information [Abstract]
Document Type	8-K
Document Period End Date	Nov. 07, 2022
Entity File Number	001-36576
Entity Registrant Name	Marinus Pharmaceuticals, Inc.
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Entity Address, Address Line Three	100 Matsonford Rd
Entity Address, City or Town	Radnor
Entity Address, Postal Zip Code	19087
City Area Code	484
Local Phone Number	801-4670
Title of 12(b) Security	Common Stock, par value $0.001
Trading Symbol	MRNS
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Entity Emerging Growth Company	false
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Pre-commencement Issuer Tender Offer	false