Exercise of Option. This Option shall be exercisable during its term in accordance with the Vesting Schedule set out in the Notice of Grant and with the provisions of Sections 10 and 11 of the Plan as follows:

Exercise of Option. Effective as of today, the undersigned (“Optionee”) hereby elects to exercise Optionee’s option to purchase ​ shares of the Common Stock (the “Shares”) of Assembly Biosciences, Inc. (the “Company”) under and pursuant to the Company’s 2019 Inducement Award Plan (as amended from time to time, the “Plan”) and the Notice of Stock Option Grant dated ​, 20​ with its attached Stock Option Agreement (the “Option Agreement”). The purchase price for the Shares shall be ​ as required by this Option Agreement. Optionee herewith delivers to the Company the full Exercise Price for the Shares.

Exercise of Option. An Option to Extend shall be exercised by ​, if at all, only in the manner set forth in this Section 2.2. ​ shall deliver notice (the “Exercise Notice”) to ​ not more than fifteen (15) months nor less than nine (9) months prior to the expiration of the Lease Term or the applicable Option Term, as applicable, stating that ​ is exercising its Option to Extend, which election shall be irrevocable regardless of the fact that the

Exercise of Option. An Option shall be exercisable at such times and be subject to such restrictions and conditions as the Committee shall in each instance approve, which terms and restrictions need not be the same for each grant or for each Participant, except that no Option shall be exercisable within one (1) year from its Grant Date, except in the case of the death of the Participant.

Exercise of Option. Once vested, the Participant may exercise this Option, in whole or in part, at any time during the term as specified above but not after ten (10) years from the Date of Grant; provided, that if the Participant dies, this Option, if vested, may be exercised within three (3) years after death, but not after ten (10) years from the Date of Grant, by the Participant’s estate or by the person or persons who acquire the right to exercise this Option by bequest, inheritance or otherwise by reason of such death. ​ and the Participant recognize that this Agreement in no way restricts the right of ​ to terminate the Participant’s membership consistent with applicable Delaware laws.

Option Exercise Price. The Option Exercise Price per share of Stock purchasable under a Stock Option shall be determined by the Committee at the time of grant and shall not be less than 100% of the Fair Market Value of the Stock on the date of grant.

Exercise of Option. Exercise of the purchase rights represented by this Option may be made, in whole or in part, at any time or times during the Exercise Period by delivery to the Company at its executive offices of a duly executed copy of the Notice of Exercise Form annexed hereto; and, if the Holder opts to make cash payment, within 3 business days of the date said Notice of Exercise is delivered to the Company, the Company shall have received payment of the aggregate Exercise Price of the shares thereby purchased by wire transfer or cashier’s check or otherwise by agreement with the Company. Notwithstanding anything herein to the contrary, the Holder shall not be required to physically surrender this Option to the Company until the Holder has purchased all of the Option Shares available hereunder and the Option has been exercised in full, in which case, the Holder shall surrender this Option to the Company for cancellation within 3 business days of the date the final Notice of Exercise is delivered to the Company.

The Option shall not be exercisable as of the Grant Date set forth in the Grant Notice. After the Grant Date, to the extent not previously exercised, and subject to termination or acceleration as provided in these Standard Terms and Conditions, the Plan and, if applicable, the Key Employee Continuity Plan, the Severance Policy and/or the Policy for Recoupment of Certain Compensation, the Option shall be exercisable only to the extent it becomes vested, as described in the Grant Notice, these Standard Terms and Conditions, the terms of the Plan and, if applicable, the Key Employee Continuity Plan, the Severance Policy and/or the Policy for Recoupment of Certain Compensation, to purchase up to that number of shares of Common Stock as set forth in the Grant Notice, provided that (except as may be provided otherwise in Section 4 below) you remain employed with the Company and do not experience a termination of employment.

Exercise of Option. The Purchaser hereby elects to exercise the Option to purchase shares of Common Stock (“Shares”), all of which are vested pursuant to the terms of the Stock Option Agreement. The total Exercise Price for all of the Shares is (Total Shares times Exercise Price per Share).

Exercise of Stock Option. Subject to the provision of Paragraph 4 hereof, this Stock Option may be exercised by written notice delivered to the Company stating the number of Option Shares with respect to which this Stock Option is being exercised, together with cash and/or, if permitted at the time of exercise by the Stock Option Committee, shares of Common Stock of the Company which, when added to the cash payment, if any, have an aggregate Fair Market Value equal to the full amount of the purchase price of such Option Shares. If all or part of payment is made in shares of Common Stock as heretofore provided, such payment shall be deemed to have been made only upon receipt by the Corporation of all required share certificates, and all stock powers and other required transfer documents necessary to transfer the shares of Common Stock to the Corporation. Not less than ten (10) Option shares may be purchased at any one time unless the number purchased is the total number which remains to be purchased under this Stock Option and in no event may the Stock Option be exercised with respect to fractional shares. Upon exercise, Optionee shall make appropriate arrangements and shall be responsible for the withholding of any federal and state income taxes then due.