Agreement Subject to the Plan. This Agreement is subject to the provisions of the Plan and shall be interpreted in accordance therewith. In the event that the

Stock Subject to the Plan. Subject to adjustment upon changes in capitalization of the Company as provided in Section 14, the maximum aggregate number of Shares that may be subject to Awards and sold under the Plan will be equal to # 1,000,000 Shares, plus # any Shares subject to awards granted under the Tocagen, Inc. 2009 Equity Incentive Plan, the Tocagen, Inc. 2017 Equity Incentive Plan, and the Forte Biosciences Inc. 2018 Equity Incentive Plan that, after the date of stockholder approval of the Plan, expire or otherwise terminate without having been exercised or issued in full, are tendered to or withheld by the Company for payment of an exercise price or for tax withholding obligations, or are forfeited to or repurchased by the Company due to failure to vest, with the maximum number of Shares to be added to the Plan pursuant to clause (b) equal to 1,102,341. In addition, Shares may become available for issuance under Section 3.2. The Shares may be authorized but unissued, or reacquired Common Stock.

Subject to such additional shares of Stock as shall be available for issuance under the Plan pursuant to Section 4.2, and subject to adjustment pursuant to Section 17, the maximum number of shares of Stock available for issuance under the Plan shall be equal to 65 million shares, plus the number of shares of Stock subject to awards outstanding under the Prior Plan as of the Effective Date which thereafter terminate by expiration, forfeiture, cancellation or otherwise without the issuance of such shares.

Stock Subject to the Plan. Subject to the provisions of Section 13 hereof, the shares of stock subject to Options or Stock Purchase Rights shall be Common Stock. Subject to the provisions of Section 13 hereof, the maximum aggregate number of Shares which may be issued upon exercise of such Options or Stock Purchase Rights is Twenty-Six Million Five Hundred Forty-Two Thousand Four Hundred Eighty-Three (26,542,483) Shares. Shares issued upon exercise of Options or Stock Purchase Rights may be authorized but unissued, or reacquired Common Stock. If an Option or Stock Purchase Right expires or becomes unexercisable without having been exercised in full, the unpurchased Shares which were subject thereto shall become available for future grant or sale under the Plan (unless the Plan has terminated). Shares which are delivered by the Holder or withheld by the Company upon the exercise of an Option or Stock Purchase Right under the Plan, in payment of the exercise price thereof or tax withholding thereon, may again be optioned, granted or awarded hereunder, subject to the limitations of this Section 3. If Shares of Restricted Stock are repurchased by the Company at their original purchase price, such Shares shall become available for future grant under the Plan (unless the Plan has terminated). Notwithstanding the provisions of this Section 3, no Shares may again be optioned, granted or awarded if such action would cause an Incentive Stock Option to fail to qualify as an Incentive Stock Option under Code Section 422.

Restricted Stock Subject to Plan. This Award is subject to the Plan as approved by the Company’s stockholders and as may thereafter be amended or modified in accordance with its terms. The terms and provisions of the Plan as it may be amended from time to time are hereby incorporated herein by reference. In the event of a conflict between any term or provision contained herein and a term or provision of the Plan, the applicable terms and provisions of the Plan will govern and prevail.

Stock Subject to the Plan. Awards that are made in the form of stock, restricted stock, stock units or other forms of stock-based awards shall be made from the aggregate number of shares authorized to be issued under the terms of the Stock Plan.

Securities Subject to the Plan. The securities subject to the Plan shall consist of Common Stock and the Plan Notes. Common Stock subject to the Plan shall consist of # Shares reserved for issuance under the Plan and # Shares issuable upon conversion of Plan Notes.

Notes Subject to the Plan. Plan Notes may be subject only to Tranche A Awards under the Plan. The maximum aggregate original principal amount of Plan Notes that may be subject to Awards under the Plan shall be $2,400,000. By their terms, the Plan Notes are convertible into an aggregate of 636,877 Shares (such Shares, the “Shares Convertible from Plan Notes”).

Shares Subject to the Plan. Subject to [Section 16] of the Plan, the maximum aggregate number of Shares that may be subject to Awards under the Plan shall be 3,952,095, which amount (the “Gross Share Reserve”) consists of the sum of # the Shares Convertible from Plan Notes and # 3,315,218 additional Shares (the “Net Share Reserve”). The Gross Share Reserve, which is an amount equal to eight and three tenths percent (8.3%) of the Shares outstanding as of the Effective Date on a fully diluted basis, shall be divided into three grant pools:

GRANT OF RESTRICTED STOCK. Subject to the terms and provisions of the Plan, the Committee, at any time and from time to time, may grant Shares of Restricted Stock to Participants in such amounts as the Committee shall determine.