Amendment, dated September 17, 2021, to the Engagement Letter Agreement dated November 3, 2020 by and between the Registrant and LifeSci Capital LLC

Exhibit 10.2

September 17, 2021

Petra Acquisition, Inc.

5 West 21^st Street

New York, NY 10010

Attn: Andreas Typaldos

Dear Mr. Typaldos:

This letter amends that certain engagement letter agreement dated November 3, 2020 (the “Agreement), by and between Petra Acquisition, Inc., a Delaware corporation (collectively, with its subsidiaries and affiliates, the “Company”) and LifeSci Capital LLC (“LifeSci”), attached hereto as “Exhibit A,” pursuant to which LifeSci agreed to provide certain investment banking and financial advisory services to the Company with respect to the Company’s efforts to engage in an initial business combination transaction. Capitalized terms used herein and not otherwise defined have the meetings ascribed to them in the Agreement.

For good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the Company and LifeSci agree as follows:

(a) In the event there is a transaction (or series of related transactions) (a “Transaction”) pursuant to which Petra effectuates a merger, consolidation, reorganization, equity sale, asset sale or other business combination or similar acquisition transaction with or involving one or more potential target companies (each a “Target”) or a Target’s affiliate which qualifies as Petra’s initial business combination as described in Petra’s final prospectus, dated as of October 7, 2020 and filed with the U.S. Securities and Exchange Commission (File No. 333-240175) on October 13, 2020 that is consummated during the term of the LifeSci Engagement Letter (as extended under paragraph 5(a)), Petra shall pay LifeSci as compensation for investment banking and financial advisory services an advisory fee (the “M&A Advisory Fee”) of three and one-half percent (3.5%) of the Total Consideration (as defined below). The M&A Advisory Fee shall be payable as follows:

(i) Petra shall pay to LifeSci a cash fee equal to one percent (1.0%) of the Total Consideration in accordance with clause (b) below; and

(ii) Petra shall issue to LifeSci (or another entity designated by LifeSci) equity interests in the post-Transaction surviving entity with value upon issuance to LifeSci equal to two and one half percent (2.5%) of the Total Consideration in accordance with clause (b) below.

In addition, and notwithstanding the earlier termination of the LifeSci Engagement Letter, in the event that during the period of eighteen (18) months after termination of the LifeSci Engagement Letter (the “Tail Period”), Petra consummates a Transaction or enters into a definitive agreement with respect to a Transaction which is subsequently consummated (even if consummated after the end of the Tail Period), LifeSci shall be entitled to the M&A Advisory Fee with respect to such Transaction,(which shall be reduced by any “break-up,” “termination” or similar fee or payment from the Target as a result of the termination of an agreement to engage in a Transaction actually received by LifeSci in connection with such Transaction).

(b) For the purposes of the LifeSci Engagement Letter, “Total Consideration” means the total market value of, without duplication, all cash, securities, debt or other property paid or transferred at the closing of a Transaction by or to the Target or the Target’s shareholders or to be paid or transferred in the future to the Target’s shareholders with respect to such Transaction (other than payments of interest or dividends), including to the extent applicable, any net value paid in respect of (i) the assets of the Target, (ii) amounts paid under contractual arrangements (including lease arrangements and management fees) or for agreements not to compete or similar agreements, and (iii) the capital stock of the Target (and the spread value of any “in the money” securities convertible into options, warrants or other rights to acquire such capital stock), after giving effect to the assumption, retirement or defeasance, directly or indirectly (by operation of law or otherwise), of any long-term liabilities of the Target or repayment of indebtedness, including indebtedness secured by the assets of the Target, capital leases or preferred stock obligations; provided, that for the avoidance of doubt, any funds in a trust account established by Petra (as may be applicable in the case of a Transaction) or financing proceeds raised in connection with the closing of the Transaction (including by way of an offering of newly issued private equity or equity-linked securities of Petra for cash, that will be a Private Investment in Public Equity transaction closed immediately prior to or contemporaneously with the Transaction, the compensation to LifeSci for which is provided for above), in either case, that are not paid to the Target’s shareholders as consideration in the Transaction will not be included as part of the Total Consideration. In connection with a sale, transfer or other disposition of 50% or more of the outstanding capital stock of the Target, the Total Consideration will be calculated as if 100% of the outstanding capital stock on a fully diluted basis had been acquired at the same per share amount paid in such Transaction.

Accepted and agreed to as of the date first written above: