Histogen Inc. Form of Warrant

EXERCISE OF WARRANT.

Any time following the date hereof, this Warrant may be exercised in whole or in part at any time or from time to time until 5:00 p.m. Pacific Standard Time on December 31, 2018; provided, however, that if such day is a day on which banking institutions in the State of California are authorized by law to close, then on the next succeeding day which shall not be such a day. This Warrant may be exercised by presentation and surrender hereof to the Company at its principal office, or at the office of its stock transfer agent if any, with the Purchase Form annexed hereto duly executed and accompanied by payment of the Exercise Price for the number of Warrant Shares specified in such form. As soon as practicable after each such exercise of this Warrant, but not later than seven (7) days from the date of such exercise, the Company shall issue and deliver to the

In lieu of delivering the Exercise Price in cash or check the Holder may elect to receive shares equal to the value of the Warrant or portion thereof being exercised (“Net Issue Exercise”). If the Holder wishes to elect the Net Issue Exercise, the Holder shall notify the Company of its election in writing at the time it delivers to the Company the Purchase Form. In the event the Holder shall elect Net Issue Exercise, the Holder shall receive the number of shares of Common Stock equal to the product of (x) the number of shares of Common Stock purchasable under the Warrant, or portion thereof being exercised, and (y) the current market value, as determined in accordance with paragraph (c) below, of one share of Common Stock minus the Exercise Price, divided by (z) the current market value, as determined in accordance with paragraph (c) below, of one share of Common Stock.

RESERVATION OF SHARES. The Company shall at all times reserve for issuance and/or delivery upon exercise of this Warrant such number of shares of its Common Stock as shall be required for issuance and delivery upon exercise of the Warrants.

FRACTIONAL SHARES. No fractional shares or scrip representing fractional shares shall be issued upon the exercise of this Warrant. With respect to any fraction of a share called for upon any exercise hereof, the Company shall pay to the Holder an amount in cash equal to such fraction multiplied by the current market value of a share, determined in good faith by the Company’s Board of Directors.

EXCHANGE, TRANSFER, ASSIGNMENT OR LOSS OF WARRANT. This Warrant is exchangeable, without expense, at the option of the Holder, upon presentation and surrender hereof to the Company or at the office of its stock transfer agent, if any, for other warrants of different denominations entitling the holder thereof to purchase in the aggregate the same number of shares of Common Stock purchasable hereunder. Upon surrender of this Warrant to the Company at its principal office or at the office of its stock transfer agent, if any, with the Assignment Form annexed hereto duly executed and funds sufficient to

RIGHTS OF THE HOLDER. The Holder shall not, by virtue hereof, be entitled to any rights of a shareholder in the Company, either at law or equity, and the rights of the Holder are limited to those expressed in the Warrant and are not enforceable against the Company except to the extent set forth herein.

ANTI-DILUTION PROVISIONS. The Exercise Price in effect at any time and the number and kind of securities purchasable upon the exercise of the Warrants shall be subject to adjustment from time to time upon the happening of certain events as follows:

In case the Company shall (i) declare a dividend or make a distribution on its outstanding shares of Common Stock, (ii) subdivide or reclassify its outstanding shares of Common Stock into a greater number of shares, or (iii) combine or reclassify its outstanding shares of Common Stock into a smaller number of shares, the Exercise Price in effect at the time of the record date for such dividend or distribution or of the effective date of such subdivision, combination or reclassification shall be adjusted so that the Exercise Price shall be proportionately increased (as in the case of (iii), above) or decreased (as in the case of (i) or (ii), above). Such adjustment shall be made successively whenever any event listed above shall occur.

Whenever the Exercise Price payable upon exercise of each Warrant is adjusted pursuant to Subsection (1) above, the number of Shares purchasable upon exercise of this Warrant shall simultaneously be adjusted by multiplying the number of Shares initially issuable upon exercise of this Warrant by the Exercise Price in effect on the date hereof and dividing the product so obtained by the Exercise Price, as adjusted.

In the event that at any time, as a result of an adjustment made pursuant to Subsection (1) above, the Holder of this Warrant thereafter shall become entitled to receive any shares of the Company, other than Common Stock, thereafter the number of such other shares so receivable upon exercise of this Warrant shall be subject to adjustment from time to time in a manner and on terms as nearly equivalent as practicable to the provisions with respect to the Common Stock contained in Subsections (1) to (3), inclusive above.

Whenever the Exercise Price is adjusted, as herein provided, the Company shall promptly but no later than 20 days after any request for such an adjustment by the Holder, cause a notice setting forth the adjusted Exercise Price and adjusted number of Shares issuable upon exercise of each Warrant, and, if requested, information describing the transactions giving rise to such adjustments, to be mailed to the Holder at its last address appearing in the Warrant Register, and shall cause a certified copy thereof to be mailed to its transfer agent, if any. The Company may retain a firm of independent certified public accountants selected by the Board of Directors (who may be the regular accountants employed by the Company) to make any computation required by this Section (f), and a certificate signed by such firm shall be conclusive evidence of the correctness of such adjustment.

RECLASSIFICATION, REORGANIZATION OR MERGER. In case of any reclassification, capital reorganization or other change of outstanding shares of Common Stock of the Company, or in case of any consolidation or merger of the Company with or into another corporation (other than a merger with a subsidiary in which merger the Company is the continuing corporation and which does not result in any reclassification, capital reorganization or other change of outstanding shares of Common Stock of the class issuable upon exercise of this Warrant) or in case of any sale, lease or conveyance to another corporation of the property of the Company as an entirety, the Company shall, as a condition precedent to such transaction, cause effective provisions to be made so that the Holder shall have the right thereafter by exercising this Warrant at any time prior to the expiration of the Warrant, to purchase the kind and amount of shares of stock and other securities and property receivable upon such reclassification, capital reorganization and other change, consolidation, merger, sale or conveyance by a holder of the number of shares of Common Stock which might have been purchased upon exercise of this Warrant immediately prior to such reclassification, change, consolidation, merger, sale or conveyance. Any such provision shall include provision for adjustments which shall be as nearly equivalent as may be practicable to the adjustments provided for in this Warrant. The foregoing provisions of this Section (g) shall similarly apply to successive reclassifications, capital reorganizations and changes of shares of Common Stock and to successive consolidations, mergers, sales or conveyances. In the event that in connection with any such capital reorganization or reclassification, consolidation, merger, sale or conveyance, additional shares of Common Stock shall be issued in exchange, conversion, substitution or payment, in whole or in part, for a security of the Company other than Common Stock, any such issue shall be treated as an issue of Common Stock covered by the provisions of Subsection (1) of Section (f) hereof.

The Company will not, by amendment of its charter or through reorganization, consolidation, merger, dissolution, sale of assets or any other voluntary action, avoid or seek to avoid the observance or performance of any of the terms of this Warrant, but will at all times in good faith assist in the carrying out of all such terms and in the taking of all such action as may be necessary or appropriate in order to protect the rights of the Holder of this Warrant against impairment.