On April 30, 2020, the Company was granted a loan from Silicon Valley Bank ("SVB"), in the aggregate amount of $0.4 million, pursuant to the Paycheck Protection Program (the “PPP”) of the Coronavirus Aid, Relief and Economic Security Act of 2020 (the “CARES Act”). On June 5, 2020, the PPP Flexibility Act of 2020 (the "PPPFA") was signed into law amending the original terms of the PPP. Among other things, the PPPFA extended the deferral period for monthly principal and interest payments from six months to either (i) the date the Small Business Administration ("SBA") compensates the lender for any forgiven amounts or (ii) 10 months after the end of the borrower's loan forgiveness covered period. The PPPFA also extended the covered period for qualifying expenses from eight weeks to the earlier of 24 weeks or December 31, 2020. Certain amounts of the loan may be forgiven if they are used for qualifying expenses as described by the CARES Act.

The loan was in the form of a promissory note dated April 30, 2020 in favor of SVB (the "PPP Note"). The PPP Note matures on April 30, 2022 and bears interest at a rate of 1.0% per annum. Principal and interest payments are payable monthly commencing on either (i) the date the SBA compensates SVB for any forgiven amounts or (ii) 10 months after the end of the Company's covered period, which ended in October 2020. If the PPP Note is fully forgiven, the Company will not be responsible for any payments. The Company did not provide any collateral or guarantees for the loan, nor did the Company pay any facility charge to obtain the loan. The PPP Note provides for customary events of default, including, among others, failure to make payment, bankruptcy, breaches of representations, and material adverse events.

On April 22, 2020, in connection with the Warrant Exchange (as defined in Note 11), the Company issued to Investors certain promissory notes (the "Warrant Exchange Promissory Notes") with an aggregate principal amount of $5.6 million. The Warrant

Exchange Promissory Notes had a maturity date of April 21, 2021 and did not bear interest. The Warrant Exchange Promissory Notes were recorded at a fair value of $5.0 million. The difference of $0.6 million between the fair value and the aggregate principal amount of $5.6 million was recorded as a debt discount and accreted to interest expense over the life of the Warrant Exchange Promissory Notes. The accretion amounted to $0.6 million for the year ended December 31, 2020.

The Company was entitled to prepay the Warrant Exchange Promissory Notes in whole or in part at any time without penalty or premium. In the event that the Company consummated a financing transaction that generated cash to the Company, the Company was required to use 20% of the net proceeds of such transaction to prepay a portion of the outstanding amount under each Warrant Exchange Promissory Note if the transaction occurred on or prior to August 22, 2020, and 30% of the net proceeds to prepay a portion of the outstanding amount under each Warrant Exchange Promissory Note if that transaction occurred after August 22, 2020. As a result of the net proceeds from the ATMs discussed in Note 9 , the Company made payments to the Warrant Exchange Promissory Note holders of $5.6 million during the year ended December 31, 2020, causing the Warrant Exchange Promissory Notes to be repaid in full and no longer outstanding at December 31, 2020.

In September 2016, pursuant to the U.S. government’s Immigrant Investor Program, commonly known as the EB-5 program, the Company entered into an arrangement (the “EB-5 Loan Agreement”) to borrow up to $10.0 million from EB5 Life Sciences, L.P. (“EB-5 Life Sciences”) in $0.5 million increments. Borrowing may be limited by the amount of funds raised by the EB-5 Life Sciences and are subject to certain job creation requirements by the Company. Borrowings are at a fixed interest rate of 4.0% per annum and are to be utilized in the clinical development, manufacturing, and commercialization of the Company’s products and for the general working capital needs of the Company. Outstanding borrowings pursuant to the EB-5 Loan Agreement, including accrued interest, become due upon the seventh anniversary of the final disbursement. Amounts repaid cannot be re-borrowed. The EB-5 Loan Agreement borrowings are secured by substantially all assets of the Company, except for any patents, patent applications, pending patents, patent license, patent sublicense, trademarks, and other intellectual property rights.

Under the terms and conditions of the EB-5 Loan Agreement, the Company borrowed $1.0 million in 2016 and an additional $0.5 million on March 26, 2020. Issuance costs were recognized as a reduction to the loan balance and are amortized to interest expense over the term of the loan.

On May 21, 2019, the Company issued senior secured convertible notes to certain investors for $2.4 million at an original issue discount of $0.5 million, and on June 28, 2019, the Company entered into an agreement to issue additional senior secured convertible notes to the investors for $2.9 million with an original issue discount of $0.4 million (together the "Senior Secured Convertible Notes"). Immediately prior to the Merger, the Investors offset $5.3 million from the amount to be received under the Pre-Merger Financing and the Senior Secured Convertible Notes were deemed to have been repaid and cancelled. The accretion of the original issue discount to interest expense amounted to $0.8 million during the year ended December 31, 2019.

On April 4, 2019, the Company issued a convertible promissory note (the "Convertible Promissory Note") to an existing stockholder for $0.9 million at an interest rate of 5% per annum. On May 16, 2019, the Convertible Promissory Note was converted into equity. OpCo issued 0.1 million shares of common stock at the conversion date to extinguish the debt at $12.41 per share. This non-cash transaction resulted in an increase of $0.9 million in additional paid-in capital, which was based on the principal balance outstanding and the unpaid interest upon conversion.

During the years ended December 31, 2019 and 2018, the Company issued convertible notes (the “Convertible Notes”) to new and existing stockholders in the Company, including Convertible Notes in the aggregate principal amount of $3.5 million to members of the Board of Directors. As of December 31, 2019, all of the Convertible Notes had been converted and were no longer outstanding.


Note Issuance Date	Convertible Note Principal Amount		Fair Value of Embedded Derivatives		Debt Issuance Costs		Carrying Value upon Issuance
January 2018	$	5,000,000	$	(2,657,711)	$	(35,969)	$	2,306,320
June 2018	1,000,000		(724,216)		(3,000)		272,784
November 2018	1,150,400		(21,127)		(50,646)		1,078,627
December 2018	150,000		(2,857)		(14,310)		132,833
January 2019	450,000		(182,882)		(29,358)		237,760
February 2019	1,000,000		(302,379)		(55,875)		641,746
Total	$	8,750,400	$	(3,891,172)	$	(189,158)	$	4,670,070

All Convertible Notes accrued interest at a rate of 5% per annum and had scheduled maturity dates on the eighteen month anniversary of the date of the issuance of the Convertible Notes (the “Maturity Date”). If prior to the Maturity Date, there was a consummation of the sale of all or substantially all of the assets of the Company, change in control, or event of default, the Convertible Notes would become due and payable at an amount equal to 1.5 times the principal amount of the Convertible Notes together with all accrued interest (the “Change in Control Feature”).

If the Company received equity financing from the issuance of stock of the Company from an investor or group of investors in a transaction or series of related transactions above a certain amount of gross proceeds, the principal amount and all interest accrued but not paid through the closing date of the qualified equity financing was to automatically convert into the same class of equity securities as those issued in the qualified equity financing ("Conversion Feature"). The price per share varied among the Convertible Notes ranging from a 0% to 30% discount to the lowest price per share being paid by investors in the qualified equity financing.

The Company bifurcated the Conversion Feature for the January 2018, June 2018, January 2019, and February 2019 Convertible Notes and classified it as a derivative liability because the conversion feature did not have a fixed conversion price and conversion would be settled in a variable number of shares of common stock. There was no bifurcated conversion feature for the November 2018 and December 2018 Convertible Notes as there is no discount to the lowest equity price triggering conversion. The Company also bifurcated the Change in Control Feature for all of the Convertible Notes because it was determined to be a redemption feature not clearly and closely related to the debt host.

The fair value of both of the embedded features was accounted for as a derivative liability and was recorded as a discount on the Convertible Notes with subsequent changes in fair value recorded on the Company’s consolidated statements of operations and comprehensive loss as other income (expense). The fair value at the issuance of each Convertible Note and at the end of each reporting period were estimated using an income approach model. Inputs used in the valuation were unobservable and therefore considered Level 3 in the fair value hierarchy. The debt discount was accreted into interest expense over the expected time until conversion of the Convertible Notes. The accretion amounted to $0.6 million for the year ended December 31, 2019. There was no accretion during the year ended December 31, 2020 as all Convertible Notes had been converted and were no longer outstanding as of December 31, 2019.

As a result of the April 2019 Subscription Agreement as described and defined within Note 9, the triggers for conversion were met on the Convertible Notes. On April 5, 2019, the Convertible Notes were modified to change the discount percentage from the 0% discount per the terms of the November 2018 and December 2018 Convertible Notes and the 15% discount per the terms of the January 2019 and February 2019 Convertible Notes to 30% at the time of conversion. The Company issued 1.1 million shares of common stock at $8.69 per share on the date of conversion to extinguish the debt, which resulted in a loss of $0.3 million. This non-cash conversion also resulted in an increase of $13.0 million in additional paid-in capital, which was based on the principal balance outstanding and the unpaid interest upon conversion.