Convertible Promissory Notes and Long-Term Debt

6 Months Ended

Jun. 30, 2022

Debt Disclosure [Abstract]

Convertible Promissory Notes and Long-Term Debt

4. Convertible Promissory Notes and Long-Term Debt

Frazier Convertible Note Financings

During 2019, 2020 and 2021, the Company issued the Frazier Notes for an aggregate of $8.5 million bearing interest at per annum rates ranging from 0.12% to 2.52%. An aggregate of $0.9 million of the Frazier Notes were issued in April, May

and September of 2019 (the “2019 Frazier Notes”), an aggregate of $1.3 million of the Frazier Notes were issued in March, August and October of 2020 (the “2020 Frazier Notes”) and an aggregate of $6.3 million of Frazier Notes were issued from April to July 2021 (the “2021 Frazier Notes”). The Frazier Notes were generally scheduled to mature 12 to 18 months from the date of issuance. The Company recorded changes in the fair value of the Frazier Notes in the condensed consolidated statements of operations. The Frazier Notes were exchanged for convertible promissory notes newly issued in connection with the August 2021 convertible note financing described below. For the three and six months ended June 30, 2021, the Company recognized a $0.4 million and $0.5 million, respectively, change in fair value of convertible promissory notes and recognized $8,000 and $17,000, respectively, of interest expense in connection with outstanding Frazier Notes.

August 2021 Convertible Note Financing

On August 31, 2021, the Company entered into a note purchase agreement under which it issued the August 2021 Notes for an aggregate of $139.52 million. Of the August 2021 Notes, $103.75 million were issued to new investors, $25.0 million were issued to Frazier for cash and $10.77 million were issued to Frazier in exchange for the then outstanding principal and accrued interest on the Frazier Notes. The August 2021 Notes bear interest at a rate of 6% per annum, compounded annually. For the three and six months ended June 30, 2022, the Company recognized a $34.4 million and $51.5 million, respectively, change in fair value of convertible promissory notes in the condensed consolidated statements of operations and recognized $0.7 million and $2.8 million, respectively, of interest expense in connection with outstanding August 2021 Notes. As of December 31, 2021, the outstanding principal balance of the August 2021 Notes was $139.5 million. The principal and accrued interest on the August 2021 Notes automatically converted into 10,672,138 shares of the Company's common stock immediately prior to the completion of the IPO.

Long-Term Debt

The Company’s Term Loan consists of the following (in thousands):

	June 30, 2022
Long-term debt	$	5,000
Accumulated PIK interest		21
Total principal (including PIK interest)		5,021
Unamortized debt discount		(324	)
Long-term debt, net of debt discount	$	4,697

On April 18, 2022, the Company entered into a Loan and Security Agreement (“Loan Agreement”) with Hercules Capital, Inc. (“Hercules”), as administrative and collateral agent, and the lenders party thereto¸ providing for term loans (“Term Loans”) of up to $75.0 million in the aggregate. The Company borrowed $5.0 million on April 18, 2022 and has the right to borrow up to an additional $10.0 million through December 15, 2022 and up to an additional $15.0 million through June 30, 2023 (collectively, “Term Loan 1”). The Company also has the right to borrow up to $20.0 million through June 30, 2023 (“Term Loan 2”). In addition, the Company has the right to borrow $25.0 million through March 31, 2024 (“Term Loan 3”), provided that on or prior to March 31, 2023, (i) the Company has announced that the planned Phase 2b clinical trial evaluating the safety, immunogenicity, and efficacy of HIL-214 in infants (“HIL-214 Vaccine Trial”) will continue without material adverse modification after completion of the planned interim safety and immunogenicity analysis on the first 200 evaluable subjects in the HIL-214 Vaccine Trial, and (ii) the Company has announced the completion of subject enrollment for the HIL-214 Vaccine Trial, which shall involve the enrollment of approximately 3,000 or more subjects. All Term Loans are subject to a minimum draw amount of $5.0 million and no event of default under the Loan Agreement having occurred and is continuing. The borrowings under the Loan Agreement are collateralized by substantially all of the Company’s assets, including intellectual property and certain other assets.

The Term Loans bear (a) cash interest at a floating rate of the higher of (i) the Wall Street Journal prime rate (or 5.00% if less) plus 1.05%, or (ii) 4.55% (interest rate of 5.80% as of June 30, 2022), and (b) additional interest ("PIK Interest") at a per annum rate equal to 2.85%, with such interest being added to the outstanding principal balance of the Term Loans on a monthly basis. The monthly payments consist of interest-only through June 1, 2025 or, if prior to April 30, 2025, (x) the conditions to Term Loan 3 have been satisfied and (y) the Company has reasonably determined that (i) the HIL-214 Vaccine Trial has achieved the protocol-specified primary efficacy endpoint and (ii) HIL-214 has demonstrated acceptable safety results in the HIL-214 Vaccine Trial, and, as a result, the Company supports the initiation of a Phase 3 registrational trial as the next immediate step in the development of HIL-214, in each case subject to reasonable verification by Hercules, through June 1, 2026. Subsequent to the interest-only period, the Term Loans will be payable in

equal monthly installments of principal, plus accrued and unpaid interest, through the maturity date of May 1, 2027. In addition, the Company is obligated to pay a final payment fee equal to the greater of (i) $2.1 million and (ii) 7.15% of the original principal amount of the Term Loans (which is $2.1 million as of June 30, 2022). The Company may elect to prepay all or a portion of the Term Loans prior to maturity, subject to a prepayment fee of up to 2.00% of the then outstanding principal balance and the pro rata application of such payment to the final payment fee. After repayment, no Term Loan amounts may be borrowed again.

The Loan Agreement contains certain customary affirmative and negative covenants and events of default. The affirmative covenants include, among others, covenants requiring the Company to maintain its legal existence and governmental approvals, deliver certain financial reports, maintain insurance coverage and satisfy certain requirements regarding its operating accounts. The negative covenants include, among others, limitations on the Company’s ability to incur additional indebtedness and liens, merge with other companies or consummate certain changes of control, acquire other companies or businesses, make certain investments, pay dividends, transfer or dispose of assets, amend certain material agreements, including the Takeda License, or enter into various specified transactions. Upon the occurrence of an event of default, subject to any specified cure periods, all amounts owed by the Company would begin to bear interest at a rate that is 4.00% above the rate effective immediately before the event of default and may be declared immediately due and payable by Hercules, as collateral agent.

During the three and six months ended June 30, 2022, the Company has recognized interest expense of $0.2 million related to the Term Loans using the effective interest method. Included in such expense is $0.1 million related to accretion of the final payment fee to other long-term liabilities, $21,000 of PIK interest, $11,000 of debt discount amortization and $0.1 million of coupon interest.

Future minimum principal and interest payments, including the final payment fee, as of June 30, 2022 are as follows (in thousands):

	June 30, 2022
Years ending December 31:
2022 (remaining 6 months)	$	137
2023		303
2024		313
2025		1,680
2026		2,654
2027		3,974
Total principal payments, interest payments and final payment fee		9,061
Less: interest, PIK interest and final payment fee		(4,040	)
Long-term debt	$	5,021