Note 6 - Stockholders’ Equity

Common Stock

At the Company’s 2024 Annual Meeting of Stockholders held on May 13, 2024, its stockholders approved an amendment to its certificate of incorporation to increase the number of authorized shares of common stock available to issue by 95,000,000 to 175,000,000 with a par value of $0.0001 per share, of which 700,000 shares are designated as “Class A common stock.” The amendment was filed with the Secretary of State of the State of Delaware on May 13, 2024.

As of December 31, 2024 and 2023, there were 700,000 shares of Class A common stock issued and outstanding to Fortress. Dividends are to be distributed pro-rata to the Class A and common stockholders. The holders of common stock are entitled to one vote per share of common stock held. The Class A common stockholders are entitled to a number of votes per share equal to 1.1 times a fraction, the numerator of which is the sum of the shares of outstanding common stock and the denominator of which is the number of shares of Class A common stock. Accordingly, the holder of shares of Class A common stock will be able to control or significantly influence all matters requiring approval by our stockholders, including the election of directors and the approval of mergers or other business combination transactions. Each share of Class A common stock is convertible, at the option of the holder thereof, into one (1) fully paid and non-assessable share of common stock subject to adjustment for stock splits and combinations.

Registered Direct Offerings

In November 2020, the Company filed a shelf registration statement on Form S - 3 (the “November 2020 S – 3”), which was declared effective in December 2020 (File No. 333 - 251005). Under the S - 3, the Company may sell up to a total of $100 million of its securities.

In February 2023, the Company closed on the February 2023 Registered Direct Offering for the issuance and sale of an aggregate of 1,180,000 shares of its common stock at a purchase price of $5.25 per share of common stock. In addition, the offering includes 248,572 shares of common stock in the form of pre-funded warrants at a price of $5.2499. The pre-funded warrants were funded in full at closing except for a nominal exercise price of $0.0001 and are exercisable commencing on the closing date and will terminate when such pre-funded warrants are exercised in full. In a concurrent private placement, Checkpoint issued and sold Series A warrants to purchase up to 1,428,572 shares of common stock and Series B warrants to purchase up to 1,428,572 shares of common stock (collectively, the “February 2023 Common Stock Warrants”). The Series A and B warrants are exercisable immediately upon issuance with an exercise price of $5.00 per share. The Series A warrants expire five years following the issuance date and the Series B warrants expire eighteen months following the issuance date. The Company also issued the placement agent warrants to purchase up to 85,714 shares of common stock with an exercise price of $6.5625 per share. The total gross proceeds from the February 2023 Registered Direct Offering were approximately $7.5 million with net proceeds of approximately $6.7 million after deducting approximately $0.8 million in commissions and other transaction costs. The shares of common stock and the shares underlying the prefunded warrants were registered for sale under the November 2020 S-3. In March 2023, the Company filed a registration statement on Form S-3 to register the February 2023 Common Stock Warrants and placement agent warrants, which was declared effective May 5, 2023 (File No. 333-270474). In February 2023, the pre-funded warrants from the February 2023 Registered Direct Offering were fully exercised. The February 2023 Common Stock Warrants and placement agent warrants met the criteria for equity classification. In October 2023, the February 2023 Common Stock Warrants were fully exercised at a reduced exercise price of $1.76 per share as part of the October 2023 Inducement (see below).

In April 2023, the Company closed on the April 2023 Registered Direct Offering for the issuance and sale of an aggregate of 1,700,000 shares of its common stock at a purchase price of $3.60 per share of common stock. In a concurrent private placement, Checkpoint issued and sold Series A warrants to purchase up to 1,700,000 shares of common stock and Series B warrants to purchase up to 1,700,000 shares of common stock (collectively, the “April 2023 Common Stock Warrants”). The Series A and B warrants are exercisable immediately upon issuance with an exercise price of $3.35 per share. The Series A warrants expire five years following the issuance date and the Series B warrants expire eighteen months following the issuance date. The Company also issued the placement agent warrants to purchase up to 102,000 shares of common stock with an exercise price of $4.50 per share. The total gross proceeds from the April 2023 Registered Direct Offering were approximately $6.1 million with net proceeds of approximately $5.5 million after deducting approximately $0.6 million in commissions and other transaction costs. The shares of common stock were registered for sale under the November 2020 S-3. In April 2023, the Company filed a registration statement on Form S-3 to register the April 2023 Common Stock Warrants and placement agent warrants, which was declared effective May 5, 2023 (File No. 333-271171). The April 2023 Common Stock Warrants and placement agent warrants met the criteria for equity classification. The Series B warrants expired in October 2024 without being exercised.

The November 2020 Form S-3 expired in December 2023.

In March 2023, the Company filed a shelf registration statement on Form S-3 (the “March 2023 S-3”), which was declared effective May 5, 2023 (File No. 333-270843). Under the March 2023 S-3, the Company may sell up to a total of $150 million of its securities.

In May 2023, the Company closed on the May 2023 Registered Direct Offering for the issuance and sale of an aggregate of 1,650,000 shares of its common stock at a purchase price of $3.071 per share of common stock. In addition, the offering includes 1,606,269 shares of common stock in the form of pre-funded warrants at a price of $3.0709. The pre-funded warrants were funded in full at closing except for a nominal exercise price of $0.0001 and are exercisable commencing on the closing date and will terminate when such pre-funded warrants are exercised in full. The common stock and the pre-funded warrants were sold together with Series A warrants to purchase up to 3,256,269 shares of common stock and Series B warrants to purchase up to 3,256,269 shares of common stock (collectively, the “May 2023 Common Stock Warrants”). The Series A and B warrants are exercisable immediately upon issuance with an exercise price of $2.821 per share. The Series A warrants expire five years following the issuance date and the Series B warrants expire eighteen months following the issuance date. The Company also issued the placement agent warrants to purchase up to 195,376 shares of common stock with an exercise price of $3.8388 per share. The total gross proceeds from the May 2023 Registered Direct Offering were approximately $10.0 million with net proceeds of approximately $9.1 million after deducting approximately $0.9 million in commissions and other transaction costs. The shares of common stock and the shares underlying the prefunded warrants, May 2023 Common Stock Warrants, and placement agent warrants were registered for sale under the March 2023 S-3. In August 2023, the pre-funded warrants from the May 2023 Registered Direct Offering were fully exercised. The May 2023 Common Stock Warrants and placement agent warrants met the criteria for equity classification. The Series B warrants were exercised in full in November 2024 (see below).

In July 2023, the Company closed on the July 2023 Registered Direct Offering for the issuance and sale of an aggregate of 2,427,186 shares of its common stock at a purchase price of $3.09 per share of common stock. In addition, the offering includes 809,062 shares of common stock in the form of pre-funded warrants at a price of $3.0899. The pre-funded warrants were funded in full at closing except for a nominal exercise price of $0.0001 and are exercisable commencing on the closing date and will terminate when such pre-funded warrants are exercised in full. The common stock and the pre-funded warrants were sold together with Series A warrants to purchase up to 3,236,248 shares of common stock and Series B warrants to purchase up to 3,236,248 shares of common stock (collectively, the “July 2023 Common Stock Warrants”). The Series A and B warrants are exercisable immediately upon issuance with an exercise price of $2.84 per share. The Series A warrants expire five years following the issuance date and the Series B warrants expire eighteen months following the issuance date. The Company also issued the placement agent warrants to purchase up to 194,175 shares of common stock with an exercise price of $3.8625 per share. The total gross proceeds from the July 2023 Registered Direct Offering were approximately $10.0 million with net proceeds of approximately $9.1 million after deducting approximately $0.9 million in commissions and other transaction costs. The shares of common stock and the shares underlying the prefunded warrants, July 2023 Common Stock Warrants, and placement agent warrants were registered for sale under the March 2023 S-3. In September 2023, the pre-funded warrants from the July 2023 Registered Direct Offering were fully exercised. The July 2023 Common Stock Warrants and placement agent warrants met the criteria for equity classification.

In January 2024, the Company closed on the January 2024 Registered Direct Offering for the issuance and sale of an aggregate of 1,275,000 shares of its common stock at a purchase price of $1.805 per share of common stock. In addition, the offering includes 6,481,233 shares of common stock in the form of pre-funded warrants at a price of $1.8049. The pre-funded warrants were funded in full at closing except for a nominal exercise price of $0.0001, are exercisable commencing on the closing date, and will terminate when such pre-funded warrants are exercised in full. In a concurrent private placement, the Company issued and sold common warrants to purchase up to 7,756,233 shares of common stock (the “January 2024 Common Stock Warrants”). The January 2024 Common Stock Warrants are exercisable immediately upon issuance with an exercise price of $1.68 per share and expire five years following the issuance date. The Company also issued the placement agent warrants to purchase up to 465,374 shares of common stock with an exercise price of $2.2563 per share. The total gross proceeds from the January 2024 Registered Direct Offering were approximately $14.0 million with net proceeds of approximately $12.6 million after deducting approximately $1.4 million in commissions and other transaction costs. The shares of common stock and the shares underlying the pre-funded warrants were registered for sale under the March 2023 S-3. In March 2024, the Company filed a registration statement on Form S-3 to register the January 2024 Common Stock Warrants and placement agent warrants, which was declared effective April 5, 2024 (File No. 333-278397). In July 2024, the pre-funded warrants from the January 2024 Registered Direct Offering were fully exercised. The January 2024 Common Stock Warrants and placement agent warrants met the criteria for equity classification.

In July 2024, the Company closed on the July 2024 Registered Direct Offering for the issuance and sale of an aggregate of 1,230,000 shares of its common stock at a purchase price of $2.05 per share of common stock. In addition, the offering includes 4,623,659 shares of common stock in the form of pre-funded warrants at a price of $2.0499. The pre-funded warrants were funded in full at closing except for a nominal exercise price of $0.0001, are exercisable commencing on the closing date, and will terminate when such pre-funded warrants are exercised in full. In a concurrent private placement, the Company issued and sold common warrants to purchase up to 5,853,659 shares of common stock (the “July 2024 Common Stock Warrants”). The July 2024 Common Stock Warrants have an exercise price of $2.05 per share, will be exercisable after requisite approval of our stockholders is received, and have a term of exercise of five years from the issuance date. The Company also issued the placement agent warrants to purchase up to 351,220 shares of common stock with an exercise price of $2.5625 per share. The total gross proceeds from the July 2024 Registered Direct Offering were approximately $12.0 million with net proceeds of approximately $11.0 million after deducting approximately $1.0 million in commissions and other transaction costs. The shares of common stock and the shares underlying the pre-funded warrants were registered for sale under the March 2023 S-3. In August 2024, the Company filed a registration statement on Form S-3 to register the July 2024 Common Stock Warrants and placement agent warrants, which was declared effective August 30, 2024 (File No. 333-281650). In November 2024, the pre-funded warrants from the July 2024 Registered Direct Offering were fully exercised. The July 2024 Common Stock Warrants and placement agent warrants met the criteria for equity classification.

In November 2024, the Company received approximately $9.2 million from the exercise of existing Series B warrants for the issuance of 3,256,269 shares of common stock from the May 2023 Registered Direct Offering with an exercise price of $2.821 per share. Due to the beneficial ownership limitation provisions in the securities purchase agreement, the shares were initially unissued and held in abeyance for the benefit of the holder until notice from the holder that the shares may be issued in compliance with the agreement. As of December 31, 2024, 1,437,000 shares remained in abeyance. These shares were fully issued to the holder in February 2025.

As of December 31, 2024, approximately $65.7 million of securities remain available for sale under the March 2023 S-3.

Warrant Inducement

In October 2023, the Company entered into the October 2023 Inducement with a holder of certain of its existing warrants to exercise for cash an aggregate of 6,325,354 shares of the Company’s common stock at a reduced exercise price of $1.76 per share. The exercised warrants included Series A warrants to purchase up to 1,734,105 shares of common stock and Series B warrants to purchase up to 1,734,105 shares of common stock (collectively, the “December 2022 Common Stock Warrants”) with an original exercise price of $4.075 per share, which were issued as part of a registered direct offering the Company closed on in December 2022 (the “December 2022 Registered Direct Offering”), and the February Common Stock Warrants with an original exercise price of $5.00 per share,. which were issued as part of the February 2023 Registered Direct Offering. As part of the October 2023 Inducement, the Company agreed to issue new unregistered Series A Warrants to purchase up to 6,325,354 shares of Common Stock and new unregistered Series B Warrants to purchase up to 6,325,354 shares of Common Stock. The Series A and B warrants are exercisable immediately upon issuance with an exercise price of $1.51 per share. The Series A warrants expire five years following the issuance date and the Series B warrants expire

twenty-four months following the issuance date. The Company also issued the placement agent warrants to purchase up to 379,521 shares of common stock with an exercise price of $2.20 per share. The total gross proceeds from the October 2023 Inducement were approximately $11.1 million with net proceeds of approximately $10.0 million after deducting approximately $1.1 million in commissions and other transaction costs. In November 2023, the Company filed a registration statement on Form S-3 to register the October 2023 Common Stock Warrants and placement agent warrants, which was declared effective November 24, 2023 (File No. 333-275644). The October 2023 Common Stock Warrants and placement agent warrants met the criteria for equity classification.

The December 2022 Common Stock Warrants, which were liability classified, were revalued on October 4, 2023 using Black-Scholes Model to calculate the difference in fair value as a result of the change in exercise price. The difference in fair value of $1.2 million was recorded as a loss on common stock warrant liabilities in the Statements of Operations. The issuance of the October 2023 Common Stock Warrants was also considered as part of the cost of the inducement and were valued using Black-Scholes Model and allocated between the December 2022 Common Stock Warrants and the February 2023 Common Stock Warrants on a weighted basis. The approximately $7.7 million allocated to the December 2022 Common Stock Warrants was recorded as loss on common stock warrant liabilities in the Statements of Operations with a corresponding offset to additional paid-in-capital (see Note 7).

The February 2023 Common Stock Warrants, which were equity classified and treated under ASC 815-40, Derivatives and Hedging - Contracts in Entity’s Own Equity, were revalued using Black-Scholes Model to calculate the difference in fair value as a result of the change in exercise price. The difference in fair value of $1.1 million was deemed to be a dividend and recorded to additional paid-in-capital because the Company had an accumulated deficit on the exercise date. The approximately $6.3 million allocated to the February 2023 Common Stock Warrants from the issuance of the October 2023 Common Stock Warrants was also deemed to be a dividend and recorded to additional paid-in-capital because the Company had an accumulated deficit on the exercise date. As a result, the Company presents a deemed dividend for the modification of the February 2023 Common Stock Warrants and issuance of the October 2023 Common Stock Warrants of $7.5 million for the year ended December 31, 2023. The deemed divided was included in net loss attributable to common stockholders in the calculation of net loss per share in the consolidated statements of operations (see Note 2).

Upon the close of the transaction, the Company issued the holder 110,000 of the 6,325,354 shares of common stock that were issuable upon exercise of the existing warrants. Due to the beneficial ownership limitation provisions in the inducement offer letter agreement, the remaining 6,215,354 shares were initially unissued, and held in abeyance for the benefit of the holder until notice from the holder that the shares may be issued in compliance with the agreement. As of December 31, 2023, 1,134,000 shares remained in abeyance. These shares were fully issued to the holder in January 2024.

Shares Issued Under the Founders Agreement

Pursuant to the Founders Agreement, the Company issued to Fortress 2.5% of the aggregate number of shares of common stock issued in the offerings and warrant exercises noted above. Accordingly, the Company issued 421,653 and 398,660 shares to Fortress for the years ended December 31, 2024 and 2023, respectively, and recorded expenses of approximately $1.0 million each year related to these stock grants, which is included in general and administrative expenses in the Company’s Statements of Operations for the years ended December 31, 2024 and 2023, respectively.

Pursuant to the Founders Agreement, the Company issued 2,386,808 shares of common stock to Fortress for the Annual Equity Fee, representing 2.5% of the fully diluted outstanding equity of the Company on January 1, 2025. Because the number of outstanding shares issuable to Fortress was determinable on January 1, 2025 prior to the issuance of the December 31, 2024 financial statements, the Company recorded approximately $7.6 million in research and development expense and a credit to Common shares issuable-Founders Agreement during the year ended December 31, 2024.

Pursuant to the Founders Agreement, the Company issued 1,492,915 shares of common stock to Fortress on May 16, 2024 for the Annual Equity Fee, representing 2.5% of the fully diluted outstanding equity of the Company on January 1, 2024. The Company did not have enough unreserved authorized shares under its certificate of incorporation on January 1, 2024 to issue the shares for the Annual Equity Fee. Therefore, in December 2023, Fortress and Checkpoint mutually agreed to defer the issuance until such time as the certificate of incorporation has been amended in order to increase the number of authorized shares that may be issued thereunder (see Notes 2 and 4). At the Company’s 2024 Annual Meeting of Stockholders held on May 13, 2024, its stockholders approved an amendment to its certificate of incorporation to increase the number of authorized shares of common stock available to issue. Because the number of

outstanding shares issuable to Fortress was determinable on January 1, 2024 prior to the issuance of the December 31, 2023 financial statements, the Company recorded approximately $3.4 million in research and development expense and a credit to Common shares issuable-Founders Agreement during the year ended December 31, 2023.

The Company may offer the securities under the S-3 from time to time in response to market conditions or other circumstances if it believes such a plan of financing is in the best interests of its stockholders.

Equity Incentive Plan

The Company has in effect the Amended and Restated 2015 Incentive Plan (“2015 Incentive Plan”). The 2015 Incentive Plan was adopted in March 2015 by our stockholders. Under the 2015 Incentive Plan, the compensation committee of the Company’s board of directors is authorized to grant stock-based awards to directors, officers, employees and consultants. At the Company’s 2024 Annual Meeting of Stockholders held on May 13, 2024, its stockholders approved an amendment to the 2015 Incentive Plan to increase the shares available for issuance to 18,000,000 shares. The plan expires 10 years from the effective date of the amendment and limits the term of each option to no more than 10 years from the date of grant.

On May 24, 2024, the Company filed a registration statement on Form S-8 under the Securities Act registering the common stock issued, issuable or reserved for issuance under our 2015 Incentive Plan. The registration statement became effective immediately upon filing, and shares covered by the registration statement are eligible for sale in the public markets, subject to grant of the underlying awards, vesting provisions and Rule 144 imitations applicable to our affiliates.

As of December 31, 2024, 8,010,406 shares are available for issuance under the 2015 Incentive Plan.

Restricted Stock Awards

Certain employees, directors and consultants have been awarded restricted stock. The restricted stock vesting consists of milestone and time-based vesting. The following table summarizes restricted stock award activity for the years ended December 31, 2024 and 2023:

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As of December 31, 2024, there was $4.8 million of total unrecognized compensation cost related to non-vested restricted stock, which is expected to be recognized over a weighted-average period of 1.7 years. In December 2024, the Company announced that the FDA granted approval of UNLOXCYT for the treatment of adults with metastatic CSCC or locally advanced CSCC who are not candidates for curative surgery or curative radiation. Approximately 1.5 million shares of restricted stock vested upon this achievement and the Company recorded expense of $4.4 million in the Company’s Statements of Operations for the year ended December 31, 2024.

Restricted Stock Units

Certain employees and directors have been awarded restricted stock units. The following table summarizes restricted stock units activity for the years ended December 31, 2024 and 2023:

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All restricted stock units were performance-based with vesting upon the achievement of certain corporate milestones. In December 2024, the Company announced that the FDA granted approval of UNLOXCYT for the treatment of adults with metastatic CSCC or locally advanced CSCC who are not candidates for curative surgery or curative radiation. Approximately 2.8 million restricted stock units vested upon this achievement and the Company recorded expense of $5.7 million in the Company’s Statements of Operations for the year ended December 31, 2024.

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Stock Options

The following table summarizes stock option award activity for the years ended December 31, 2024 and 2023:

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Upon the exercise of stock options, the Company will issue new shares of its common stock.

The Company used the Black-Scholes Model for determining the estimated fair value of stock-based compensation related to stock options. The table below summarizes the assumptions used:

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Warrants

A summary of warrant activities for year ended December 31, 2024 and 2023 is presented below:

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Upon the exercise of warrants, the Company will issue new shares of its common stock.

Stock-Based Compensation

The following table summarizes stock-based compensation expense for the years ended December 31, 2024 and 2023 (in thousands).

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