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)

September 26, 2019

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)	(I.R.S. Employer Identification No.)

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:

o            Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

o            Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

o            Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

o            Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Title of Each Class	Trading Symbol(s)	Name of Each Exchange on Which Registered
Common Stock, par value $0.001 per share	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 x

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. x

Item 8.01.             Other Events.

On September 26, 2019, Marinus Pharmaceuticals, Inc. (the “Company”) conducted an investor conference call and webcast and issued a press release announcing data from its Phase 2 clinical trial in patients with refractory status epilepticus.  A copy of the slides presented during that call is filed as Exhibit 99.1 to this Current Report on Form 8-K and a copy of the press release is filed as Exhibit 99.2 to this Current Report on Form 8-K and are incorporated by reference in this Item 8.01 as though fully set forth herein.

Item 9.01.             Financial Statements and Exhibits.

Exhibit No.	Exhibit Description
99.1	Slide Presentation at Investor Conference Call and Webcast on September 26, 2019 at 8:30 a.m. ET
99.2	Press Release dated September 26, 2019

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SIGNATURE

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.
By:	/s/ Edward Smith
	Edward Smith,
	Vice President, Chief Financial Officer,
	Secretary and Treasurer

Date:  September 26, 2019

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EX-99.1

Exhibit 99.1

Ganaxolone for the Treatment of RSE September 26, 2019

Safe Harbor Statement 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 interpretation of preclinical studies, development plans for our product candidate, including the development of dose forms, the clinical trial testing schedule and milestones, the ability to complete enrollment in our clinical trials, interpretation of scientific basis for ganaxolone use, timing for availability and release of data, the safety, potential efficacy and therapeutic potential of our product candidate and our expectation regarding the sufficiency of our working capital. Forward-looking statements in this 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, the uncertainties inherent in the conduct of future clinical trials, the timing of the clinical trials, enrollment in clinical trials, availability of data from ongoing clinical trials, expectations for regulatory approvals, the attainment of clinical trial results that will be supportive of regulatory approvals, and other matters, including the development of formulations of ganaxolone, and the availability or potential availability of alternative products or treatments for conditions targeted by the company that could affect the availability or commercial potential of our drug candidates. Marinus undertakes no obligation to update or revise 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 the business of the Company in general, see Marinus' 10-K dated March 12, 2019 and other filings by the company with the U.S. Securities and Exchange Commission. You may access these documents for free by visiting EDGAR on the SEC web site at www.sec.gov. 2

Status Epilepticus (SE) is the most life-threatening occurrence within the spectrum of epileptic disorders Continuous seizures lasting >5 min for convulsive seizures or >30 minutes for non-convulsive seizures Heterogenous patient population with various/unknown etiologies Prolonged seizure activity can result in permanent neuronal damage and contribute to the high morbidity and mortality rates associated with SE SE becomes more difficult to control as its duration increases and is associated with increased mortality RSE Overview 3 RSE defined as failure of at least one 2nd line intravenous (IV) anti-epileptic drug (AED) Super Refractory Status Epilepticus (SRSE) is SE that continues or recurs 24hrs or more after the onset of IV anesthetics or failure to wean off IV anesthetics No approved therapies for RSE globally

Goals of a new treatment for RSE Prevent patient progression towards escalation of treatment (IV anesthetics) Rapid cessation of SE Maintenance of seizure control over study period Goals of a New Therapy for the Treatment of RSE Benzodiazepine Administered Medically induced Coma Established Status Epilepticus (ESE) 1st line 4 2nd line IV AED’s 3rd line IV Anesthetics Super Refractory Status Epilepticus (SRSE) Refractory Status Epilepticus (RSE)

Mortality Overall mortality is ~17-39% in RSE patients3,7 Mean RSE duration (in hrs.) between survivors and non-survivors was found to be 88.9 and 120.3 (p=0.002)3 Hospital stay Patients that achieve SE cessation within 1 or 12 hours (convulsive or non-convulsive SE, respectively) spent significantly less days in the hospital (p<0.001)5 General Outcomes Mean RSE duration between patients that had a ‘good’ or ‘bad’ outcomes were 7 and 14 days (p=0.003)4 Refractory Status Epilepticus is a Neurological Emergency 5 1 Betjemann JP & Lowenstein DH 2015 Lancet Neurol 2 Sutter R et al. 2013 Nature Reviews Neurology 3 Sutter R et al. 2013 Epilepsia 4 Madžar D et al. 2016 J. Neurol. 5 Kellinghaus C et al. 2019 Ann. Neurol. 7Novy et al 2010 6 Hockher SE et al. 2013 JAMA Neurol. Increased duration of SE leads to neuronal damage, pharmacoresistance, and generally worse outcomes1,2 3rd line IV anesthetics are generally effective at achieving SE cessation however are associated with significant complications6 More infections during SE (p<0.0001) Increased hospital stay (29 days vs. 19 days, p=0.0005) ~2.9x increased relative risk for death Increased ICU stay (14 days vs. 5 days, p<0.0001)

Ganaxolone has demonstrated a broad range of anticonvulsant and psychotherapeutic responses Rationale for IV Ganaxolone for the Treatment of RSE Benzodiazepines are effective in treating acute seizures but not RSE Benzodiazepines are positive allosteric modulators of the synaptic (gamma subunit) GABAA receptor These receptors down-regulate with prolonged seizures and explains why SE patients become refractory to benzodiazepines These receptors also down-regulate with chronic benzodiazepine administration Ganaxolone is a positive allosteric modulator of the synaptic and extrasynaptic (delta subunit) GABAA receptors The extrasynaptic receptor does not down regulate with prolonged seizures and explains why SE patients remain responsive to ganaxolone The extrasynaptic receptor does not down regulate with chronic GNX administration therefore patients should be responsive to ganaxolone with chronic dosing 6

Treatment Period Loading Dose Maintenance Taper Phase 2 RSE Trial Design Diagnosis of convulsive or non-convulsive SE Failed at least one 2nd line IV AED but not progressed to 3rd line IV anesthetics Bolus plus continuous infusion 2-4 day infusion 18 hour taper Screening Post-treatment Follow-up 24 hr Weeks 2, 3, 4 7 RSE Patients Cohort Dose of GNX/day N Low 500mg/day 5 Medium 650mg/day 4 Target 713mg/day 8 Evaluate safety, tolerability, efficacy, and pharmacokinetics of IV Ganaxolone in RSE patients Endpoints Primary: number of patients who do not require escalation of treatment with IV anesthetic within the first 24 hours after ganaxolone initiation Secondary: additional efficacy, safety and tolerability

17 patients 8 males, 9 females, Mean Age 56.9 years (range: 23 – 88) Varied reasons for RSE (e.g., brain tumors, vascular (stroke, hemorrhage), metabolic, autoimmune, alcohol withdrawal, illicit drug overdose) Types of SE 5 (29%) convulsive SE 11 (65%) non-convulsive, and 1 (6%) convulsive SE progressing to non-convulsive SE History of epilepsy 7 (41%) had history of epilepsy 10 (59%) no history of epilepsy Mean # of failed IV AEDs including benzodiazepines 2.9 (range: 2-5) Mean # of failed 2nd line IV AEDs 2.1 (range: 1-4) All 17 patients (100%) failed levetiracetam or lacosamide before receiving GNX Baseline Characteristics 8

Phase 2 RSE Trial – Efficacy of IV Ganaxolone 9 Cohort No escalation to IV anesthetics within 24 hours from infusion initiation (Primary Endpoint) Status-free at 24 hours from infusion initiation No escalation to additional IV AEDs or IV anesthetics for status relapse at any time through the follow up period* Target (713 mg/day; n=8) 100% (8 of 8) 88% (7 of 8) 100% (8 of 8) Medium (650 mg/day; n=4) 100% (4 of 4) 100% (4 of 4) 75% (3 of 4) Low (500 mg/day; n=5) 100% (5 of 5) 100% (5 of 5) 60% (3 of 5) *Follow up period equals end of taper to 24 hours post taper Two patients escalated to 3rd line therapy for seizure relapse @ Day3 One patient escalated to additional IV AED @ Day 1 for seizure relapse. One patient experienced status relapse @ Day 2 (during taper). One patient had status relapse @ Day 1, which resolved during the ganaxolone infusion without treatment escalation

Target Dose Provided Shorter ICU Time and Greater Improvements in CGI-I at Follow-up 10 CGI-I at Final Follow-up Visit (Target Dose) 3: Minimally Improved N=1 2: Much Improved N=1 1: Very Much Improved N=5 *1 patient in Target Dose died due to perforated bowel (not related)

2 related in 2 patients 2 severe sedation 13 Related in 7 subjects 6 mild (2 hypotension, 2 somnolence, 1 urinary retention, 1 hypercarbia) 5 moderate (4 somnolence; 1 hypercarbia) 2 severe (2 sedation) Phase 2 RSE Trial - IV Ganaxolone Safety Summary 11 10 SAEs in 6 patients (also included in AEs) 50 AEs in 16 subjects 8 non-related in 4 patients 37 Not-Related in 12 subjects 20 mild 8 moderate (2 pain; 2 pneumonia, 2 dysphagia, 1 delirium, 1 hypertension) 9 severe (respiratory depression, death due to withdrawal of support, sepsis, embolic stoke, perforated bowel, fall, loss of consciousness, multiple fractures, pneumothorax) 1 Death due to withdrawal of life support 1 Respiratory depression 1 Bowel perforation (fatal) 1 Sepsis (fatal) 1 Fall 1 Loss of consciousness 1 Pneumothorax 1 Multiple fracture Intubation 9 patients were not intubated upon enrollment. Of these, 6 remained intubation-free during the entire ganaxolone treatment period

Status Epilepticus - U.S. Hospital Incidence 75K Total SE Patients Annually in U.S. 23 unique ICD-10 codes with some reference to SE Refractory SE patient volumes range from 12.5K to 37.5K Minimum = patients coded as “intractable” in ICD-10 (understated) Maximum = 30%-50% of patients cited as refractory in med literature Primary market research & clinicians confirm refractory patients in range of medical literature Current SE treatment approach is clinically deficient High level of mortality for refractory patients @ 40% High levels of morbidities with existing treatments Co-morbidities extend beyond SE to include infection, etc. Average hospital length of stay for refractory = 7-17 days SE presents a very high cost burden to HC system Average cost of therapy for case ranges from $50k-$75K DRG < average cost of treatment, many hospitals losing $$ Primary cost of care drivers are ICU and treatment complications ~75K Hospital SE Patients (ICD-10) Both SE & RSE fall within the orphan drug designation 12 ~38K Patients 50% ~12K Patients 16% ~25K Patients 34% Tractable SE Min. RSE Potential RSE

No patients progressed to IV anesthetics during first 24 hours Median time to SE cessation = 5 minutes (n=15 evaluable) Durable response throughout study period in target dose cohort Patients failed mean of 2.1 second line IV AEDs Highly heterogeneous underlying cause of status Target patient population and dose identified for Ph. 3 study Ganaxolone shows an acceptable safety profile in patients with RSE Planning EOP2 meeting in Q1 2020 Phase 2 RSE Trial - Conclusions 13

Thank You

EX-99.2

Exhibit 99.2

MARINUS PHARMACEUTICALS ANNOUNCES POSITIVE TOP-LINE RESULTS WITH GANAXOLONE IN PHASE 2 REFRACTORY STATUS EPILEPTICUS TRIAL

All patients achieved the primary endpoint

Target Phase 3 dose identified

Preparing for End-of-Phase 2 meeting with FDA

Oral platform presentation at Neurocritical Care Society meeting in October

Conference call and live webcast to be held today at 8:30 AM ET

RADNOR, PA, Sept 26, 2019 (Globe Newswire) — Marinus Pharmaceuticals, Inc. (Nasdaq: MRNS) (“Marinus” or “Company”), a pharmaceutical company dedicated to the development of innovative therapeutics to treat epilepsy, depression and other neuropsychiatric disorders, today announced that it has completed the top-line analysis of the open-label, dose-finding Phase 2 study evaluating intravenous (IV) ganaxolone in patients with refractory status epilepticus (RSE). Ganaxolone met the primary endpoint in the study with no patients (n=17) progressing to IV anesthetics within 24 hours of treatment initiation. Ganaxolone had an acceptable safety and tolerability profile for the RSE patient population in all dose groups. The data have been accepted for an oral platform presentation at the Neurocritical Care Society 17th Annual Meeting in October.

Lawrence Hirsch, M.D., Professor of Neurology; Chief, Division of Epilepsy and EEG; and Co-Director of the Yale Comprehensive Epilepsy Center and Critical Care EEG Monitoring Program commented, “Maintaining control of status epilepticus without progressing to additional IV anesthetics or antiepileptic drugs (AEDs) is a remarkable clinical response to IV ganaxolone treatment. This outcome is particularly impressive given all study participants, with diverse disease etiology, had failed up to four prior AEDs. The rapid onset of activity is equally important in this patient population as a number of published studies support that stopping status earlier is a key factor in improving both short and long-term patient outcomes.”

Top-line Efficacy Data:

Cohort	No escalation to IV anesthetics within 24 hours from infusion initiation(Primary Endpoint)	Status-free at 24 hours from infusion initiation	No escalation to additional IV AEDs or IV anesthetics for status relapse at any time through the follow-up period*
Target (713 mg/day; n=8)	100% (8 of 8)	88% (7 of 8)	100% (8 of 8)
Medium (650 mg/day; n=4)	100% (4 of 4)	100% (4 of 4)	75% (3 of 4)
Low (500 mg/day; n=5)	100% (5 of 5)	100% (5 of 5)	60% (3 of 5)

*Follow up period equals end of taper to 24 hours post taper

·Median time to status cessation was 5 minutes (n=15 evaluable).

·Positive trends in health outcomes such as length of hospital stay were noted for the patients treated with ganaxolone IV at the target dose.

·Additional secondary efficacy data including four-week follow up data and health outcome measures are still being collected and analyzed, and will be announced at a later date.

“All patients who received the target dose of ganaxolone, regardless of underlying cause of status, experienced status cessation without progression to additional second line AEDs or third line anesthesia,” commented Dr. Scott Braunstein, Chief Executive Officer of Marinus.  “These data give us confidence in our IV dose selection as we make preparations for advancing into Phase 3 with our first hospital-based ganaxolone indication.  I would like to thank the study investigators, patients and their families for participating in this important study.”

Safety Data:

·Ganaxolone was shown to have an acceptable safely profile for the RSE patient population in all dose groups.

·There were 10 serious adverse events (SAEs); 8 were considered not related to treatment and two were considered treatment-related (TRSAEs). The TRSAEs were severe sedation in two patients that led to early ganaxolone discontinuation; one in the medium dose group on Day 3 and one in the target dose group on Day 1.

·There were 50 adverse events (AEs), thirteen of which were treatment-related adverse events (TRAEs) reported in 7 patients.  The most commonly reported TRAEs were somnolence, mild hypotension and sedation.

Henrikas Vaitkevicius, M.D., Neurologist at Brigham and Women’s Hospital, Assistant Professor at Harvard Medical School and Study Investigator, commented, “Status epilepticus is a life threatening condition with limited therapeutic options that are associated with significant systemic toxicities which frequently affect patient outcomes. Neurosteroids, as a group, seem to have no or minimal activity on targets outside of the central nervous system, making these compounds potentially safer and much easier to use in this extremely complex and sick patient population. Indeed, in patients we treated at our center, IV ganaxolone had rapid onset and offset effects with minimal to no effects on cardiovascular, gastrointestinal, hepatic or renal organ systems, making it an exciting potential addition to the ICU armamentarium to treat refractory seizures. I believe these data may represent the emergence of a new treatment paradigm for RSE with primary objective to rapidly break status and prevent progression to third line treatments including anesthesia.”

The Phase 2 RSE proof-of-concept clinical trial is an open-label, efficacy, safety and PK, dose-finding study conducted at 8 sites in the U.S. The study enrolled 17 medically heterogeneous patients that received an infusion of IV ganaxolone (adjunctive to second line standard of care AED) for up to 96 hours followed by a taper. The three dose groups studied were a low dose (500

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mg/day), medium dose (650 mg/day) and target dose (713 mg/day). RSE patients enrolled into the study had failed a mean of 2.1 second line IV AEDs. The primary endpoint for the study is prevention of progression to third line IV anesthetics within the first 24 hours post treatment initiation. Secondary endpoints included safety, tolerability and other efficacy analyses.

Additional efficacy and safety data have been accepted for an oral platform presentation at the Neurocritical Care Society 17th Annual Meeting on October 16, 2019 at 2:15 pm PDT in Vancouver, Canada. Only 11 out of over 400 submitted abstracts have been selected for this honor.

Marinus is making preparations for an End-of-Phase 2 meeting with the FDA to discuss next steps towards a potential Phase 3 pivotal study. In parallel, the Company is evaluating a new ready-to-use dose formulation that does not require compounding, mixing or diluting. This will enable immediate administration at the bedside and ensure patients receive the benefits of treatment as rapidly as possible. This new formulation will be evaluated in a few additional patients with data to be included in the End-of-Phase 2 meeting, anticipated in Q1 2020.

Conference Call and Webcast Details

Marinus will host a conference call and live webcast with slides today at 8:30 a.m. ET. Stockholders and other interested parties may participate in the call by dialing 877-705-6003 (domestic) or 201-493-6725 (international) and referencing conference ID number 13694692. The live webcast can be accessed on the investor page of Marinus’ website at https://ir.marinuspharma.com/. A replay will be available on Marinus’ website approximately two hours after completion of the event and will be archived for up to 30 days.

About RSE

Status epilepticus (SE) is a rare epileptic seizure of prolonged duration, lasting more than five minutes for convulsive seizures or 30 minutes for non-convulsive. It is believed to affect approximately 75,000 patients in the U.S. each year.  SE is a true medical emergency that can cause permanent damage to the brain and even death if not quickly brought under control.  SE is first treated with IV benzodiazepines then IV anti-epileptic drugs.  Patients that fail second line treatment with IV AEDs, are considered to be in refractory status epilepticus (RSE). There are currently no indicated treatments for refractory RSE.  The primary treatment goals of clinicians treating SE are; to stop the patient from seizing immediately, assess and resolve the underlying medical condition, and move the patient towards discharge from the hospital as quickly as possible.

About Ganaxolone

Ganaxolone, a positive allosteric modulator of GABAA, is being developed in three different dose forms (intravenous, capsule and liquid) intended to maximize therapeutic reach to adult and pediatric patient populations in both acute and chronic care settings. Unlike benzodiazepines, ganaxolone exhibits anti-seizure and anti-anxiety activity via its effects on synaptic and extrasynaptic GABAA receptors.  Ganaxolone has been studied in more than 1,600 subjects, both pediatric and adult, at therapeutically relevant dose levels and treatment regimens for up to four years. In these studies, ganaxolone was generally safe and well-tolerated. The most commonly reported adverse events were somnolence, dizziness and fatigue.

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About Marinus Pharmaceuticals

Marinus Pharmaceuticals, Inc. is a pharmaceutical company dedicated to the development of ganaxolone, which offers a new mechanism of action, demonstrated efficacy and safety, and convenient dosing to improve the lives of patients suffering from epilepsy and depression. Ganaxolone is a positive allosteric modulator of GABAA that acts on a well-characterized target in the brain known to have anti-seizure, anti-depressant and anti-anxiety effects. Ganaxolone is being developed in IV and oral dose forms intended to maximize therapeutic reach to adult and pediatric patient populations in both acute and chronic care settings.  Marinus is conducting the first ever pivotal studies in children with CDKL5 deficiency disorder and PCDH19-related epilepsy and has recently release top-line data from Phase 2 studies in women with postpartum depression and patients with refractory status epilepticus. For more information visit www.marinuspharma.com. Please follow us on Twitter: @MarinusPharma.

Forward-Looking Statements

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 interpretation of preclinical studies, development plans for our product candidate, including the development of dose forms, the clinical study testing schedule and milestones, the ability to complete enrollment in our clinical studies, interpretation of scientific basis for ganaxolone use, timing for availability and release of data, the safety, potential efficacy and therapeutic potential of our product candidate and our expectation regarding the sufficiency of our working capital. Forward-looking statements in this 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, the uncertainties inherent in the conduct of future clinical studies, the timing of the clinical studies, enrollment in clinical studies, availability of data from ongoing clinical studies, expectations for regulatory approvals, the attainment of clinical study results that will be supportive of regulatory approvals, and other matters, including the development of formulations of ganaxolone, and the availability or potential availability of alternative products or treatments for conditions targeted by the Company that could affect the availability or commercial potential of our drug candidates. Marinus undertakes no obligation to update or revise 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 the business of the Company in general, see filings Marinus has made with the Securities and Exchange Commission.

CONTACT:

Lisa M. Caperelli

Executive Director, Investor & Strategic Relations

Marinus Pharmaceuticals, Inc.

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484-801-4674

lcaperelli@marinuspharma.com

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