On June 9, 2026, the Company’s stockholders approved an amendment to the Third Amended and Restated Certificate of Incorporation to increase the number of authorized shares of common stock from 300,000,000 shares (293,590,481 shares of voting common stock and 6,409,519 shares of non-voting common stock) to 600,000,000 shares (593,590,481 shares of voting common stock and 6,409,519 shares of non-voting common stock). On June 9, 2026, the Company filed a Certificate of Amendment to its Third Amended and Restated Certificate of Incorporation with the Secretary of State of the State of Delaware, and the amendment became effective upon filing.

In May 2026, the Company issued 51,725,000 shares of common stock at a price of $2.90 per share pursuant to a prospectus supplement dated May 4, 2026 to our shelf registration statement on Form S-3 (File No. 333-278126). The offering was underwritten by TD Securities (USA) LLC, Guggenheim Securities, LLC and Cantor Fitzgerald & Co., as joint book-running managers, and H.C. Wainwright & Co., LLC, as lead manager. Aggregate net proceeds were approximately $140,201 after deducting underwriting discounts and commissions and offering expenses.

In June 2025, the Company issued (i) 39,200,000 shares of its common stock and accompanying warrants to purchase an aggregate of 39,200,000 shares of common stock (or pre-funded warrants in lieu thereof) and (ii) in lieu of common stock, to certain investors,

pre-funded warrants to purchase an aggregate of up to 10,800,000 shares of its common stock and accompanying warrants to purchase an aggregate of 10,800,000 shares of common stock (or pre-funded warrants in lieu thereof), at an exercise price of $0.00001 per pre-funded warrant. An additional 3,090,190 common stock warrants were issued in the financing for shares purchased by the underwriters in the market to cover overallotment demand. The combined offering price of each share of common stock and accompanying common stock warrant was $2.00. The combined offering price of each pre-funded warrant and accompanying common stock warrant was $1.99999. The pre-funded warrants are exercisable immediately. The common stock and pre-funded warrants were sold in combination with an accompanying common stock warrant to purchase one share of common stock (or a pre-funded warrant in lieu thereof) for each share of common stock or pre-funded warrant sold. Each common stock warrant has an exercise price per share of $2.50. The common stock warrants are immediately exercisable from the date of issuance and will expire on September 12, 2026, fifteen months from the date of issuance. Aggregate net proceeds were $93,558 after deducting underwriting discounts and commissions and offering expenses. As of June 30, 2026, 4,800,000 pre-funded warrants had been exercised and 6,000,000 remain outstanding. In addition, as of June 30, 2026, 5,275,100 common stock warrants had been exercised for proceeds of $13,188 and 47,815,090 common stock warrants remain outstanding.

The pre-funded warrants and common stock warrants were classified as a component of permanent stockholders’ equity within additional paid-in capital and were recorded at the issuance date using a relative fair value allocation method. The pre-funded warrants and common stock warrants are equity classified because they (i) are freestanding financial instruments that are legally detachable and separately exercisable from the equity instruments, (ii) are immediately exercisable, (iii) do not embody an obligation for the Company to repurchase its shares, (iv) permit the holders to receive a fixed number of shares of common stock upon exercise, (v) are indexed to the Company’s common stock and (vi) meet the equity classification criteria. In addition, such pre-funded warrants and common stock warrants do not provide any guarantee of value or return.

On March 31, 2025, the Company converted the Form S-3ASR to a Form S-3 (File No. 333-278126) by post-effective amendments. This Form S-3 was declared effective on March 31, 2025. The Company had a Sales Agreement with TD Securities (USA) LLC (as successor to Cowen and Company, LLC) (TD Cowen) to provide for the offering, issuance and sale of up to an aggregate amount of $200.0 million of common stock from time to time in “at-the-market” offerings (2024 ATM Program) pursuant to its S-3, and subject to the limitations thereof. On June 11, 2025, the 2024 ATM Program with TD Cowen was terminated. Prior to termination, the Company sold an aggregate of 2,609,865 shares pursuant to the 2024 ATM Program for total net proceeds of $7,724, consisting of $5,129 in 2024 and $2,595 in 2025.

On August 7, 2025, the Company filed a Registration Statement (File No. 333-289339) with the Securities and Exchange Commission (SEC), which was declared effective on August 15, 2025 (2025 Shelf Registration Statement), in relation to the registration of common stock, preferred stock, debt securities, warrants and/or units of any combination thereof for the purposes of selling, from time to time, the Company’s common stock, debt securities or other equity securities in one or more offerings. The Company also simultaneously entered into a Sales Agreement with TD Cowen to provide for the offering, issuance and sale of up to an aggregate amount of $150.0 million of the Company's common stock from time to time in “at-the-market” offerings (the 2025 ATM Program) under the 2025 Shelf Registration Statement and subject to the limitations thereof (the 2025 Sales Agreement). During the year ended December 31, 2025, the Company sold 4,160,176 shares pursuant to the 2025 ATM Program for net proceeds of $10,151. During the six months ended June 30, 2026, the Company sold 10,132,367 shares, for net proceeds of $28,730. Subsequent to June 30, 2026, the Company sold 1,802,770 additional shares, for net proceeds of $5,547.

The 2019 Stock Option and Incentive Plan (2019 Plan) was approved by the Company’s board of directors on October 14, 2019, and became effective on October 23, 2019. The 2019 Plan provides for the grant of incentive stock options, nonqualified stock options, stock appreciation rights, restricted stock units, restricted stock awards, unrestricted stock awards, cash-based awards and dividend equivalent rights to the Company’s officers, employees, directors and consultants. The number of shares initially reserved for issuance under the 2019 Plan was 2,342,288, which will be increased each January 1 thereafter by 4% of the number of shares of the Company’s common stock outstanding on the immediately preceding December 31 or such lesser number of shares determined by the Company’s board of directors or compensation committee of the board of directors. On June 1, 2023, at the 2023 Annual Meeting of Stockholders of the Company, the stockholders of the Company approved Amendment No. 1 to the 2019 Plan, increasing the number of shares of common stock reserved for issuance under the 2019 Plan by 3,000,000 shares. On January 1, 2026, the total number of shares under the

2019 Plan was increased by 4,019,172 shares pursuant to the 2019 Plan Evergreen Provision. As of June 30, 2026, there were 1,063,618 shares remaining available for issuance under the 2019 Plan.

In October 2025, the Company adopted the 2025 Inducement Plan (Inducement Plan). The Inducement Plan was adopted by the Compensation Committee of the Company’s board of directors without stockholder approval pursuant to Nasdaq Listing Rule 5635(c)(4). In accordance with Rule 5635(c)(4), awards made under the Inducement Plan, including stock options and restricted stock units, may only be granted to newly hired employees as a material inducement to accept employment with the Company. Stock options granted under the Inducement Plan expire no later than ten years from the date of grant. The number of shares originally reserved for issuance under the Inducement Plan was 275,000 shares. In April 2026, the Company's board of directors authorized an increase in the number of shares of common stock reserved for issuance under the Inducement Plan to 1,275,000 shares. As of June 30, 2026, there were 1,000,000 shares available for issuance under the Inducement Plan.

On May 19, 2025, the Company’s Board of Directors approved the repricing of certain outstanding vested and unvested stock options. Pursuant to the repricing, all options granted under the 2018 Plan and 2019 Plan held by current employees, non-employee directors and certain consultants were repriced to $1.92, the closing price of the Company’s common stock on May 19, 2025, to the extent such options had an exercise price in excess of 1.5x the $1.92 closing price per share.

As a result of the repricing, 9,900,096 vested and unvested stock options outstanding as of May 19, 2025, with original exercise prices ranging from $2.88 to $23.97, were repriced. The repricing resulted in incremental stock-based compensation expense of $3,021, of which $1,813 related to vested stock option awards and has been fully recognized as of June 30, 2026, and $1,208 related to unvested stock option awards and is being amortized on a straight-line basis over the remaining vesting period of those awards.

A summary of stock option activity is presented below:


	Number of Shares			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (years)		Aggregate Intrinsic Value
Outstanding as of January 1, 2026		13,835,372		$	1.85		7.1	$	4,968
Granted		4,166,000			3.28
Exercised		(34,257	)		1.94				49
Forfeited/Cancelled		(143,975	)		2.81
Outstanding as of June 30, 2026		17,823,140		$	2.17		7.3	$	17,451
Options Exercisable at June 30, 2026		9,518,318		$	1.83		5.8	$	12,152

The aggregate intrinsic value of options is calculated as the difference between the market price of the Company’s common stock and the exercise price of the options. The weighted average grant-date fair value of stock options granted during the six months ended June 30, 2026 and 2025 was $2.83 and $1.46, respectively.

The fair value of each award is estimated using Black-Scholes based on the following assumptions:


	Six Months Ended June 30,
	2026	2025
Risk-free interest rate	3.70%—4.31%	3.94%—4.46%
Expected term	5.5 years—6.1 years	5.5 years—6.1 years
Expected volatility	114%—118%	112%—118%
Expected dividend yield	0%	0%

Black-Scholes requires the use of subjective assumptions which determine the fair value of stock-based awards. These assumptions include:

Expected term—The expected term represents the period that stock-based awards are expected to be outstanding. The expected term for option grants is determined using the simplified method, which is the midpoint between the vesting period and the contractual term of the option.

Expected volatility—Expected volatility is estimated using the Company's stock price since its IPO in October 2019.

Risk-free interest rate—The risk-free interest rate is based on the U.S. Treasury zero coupon issues in effect at the time of grant for periods corresponding with the expected term of a stock-based award.

Expected dividend—The Company has never paid dividends on its common stock and has no plans to pay dividends on its common stock. Therefore, the Company used an expected dividend yield of zero.

The Company has recorded stock-based compensation in the accompanying statements of operations as follows:


	Three Months Ended June 30,				Six Months Ended June 30,
	2026		2025		2026		2025
Research and development	$	3,136	$	3,289	$	6,075	$	5,955
General and administrative		2,363		2,416		4,680		4,911
Total	$	5,499	$	5,705	$	10,755	$	10,866

As of June 30, 2026, there was $35,488 of unrecognized compensation cost related to unvested option awards, which is expected to be recognized over a weighted-average period of 2.3 years.

The 2019 Employee Stock Purchase Plan (2019 ESPP) was approved by the Company’s board of directors on October 14, 2019, and became effective on October 23, 2019. A total of 234,229 shares of common stock were initially reserved for issuance under the 2019 ESPP, and such number of shares will be increased each January 1 thereafter through January 1, 2029 by the least of (i) 234,229 shares of common stock, (ii) 1% of the number of shares of the Company’s common stock outstanding on the immediately preceding December 31 or (iii) such lesser number of shares determined by the 2019 ESPP’s administrator. On January 1, 2026, the total number of shares available under the 2019 ESPP was increased by 234,229 shares pursuant to the 2019 Plan Evergreen Provision. As of June 30, 2026, there were 290,122 shares remaining available for issuance under the 2019 ESPP.

Employee contributions are made through payroll deductions of up to 15% of eligible compensation over the offering period. A participant may not accrue rights to purchase more than $25 worth of the Company’s common stock for each calendar year in which such right is outstanding. At the end of each offering period, shares of the Company’s common stock may be purchased at 85% of the lesser of the Company’s common stock on (i) the first trading day of the relevant offering period and (ii) the last trading day of the relevant offering period. Each offering period will be six months in duration and will commence on each December 1 and June 1.