MRSN Mersana Therapeutics Inc

On February 28, 2022, Mersana Therapeutics, Inc., a Delaware corporation (the “Company”), entered into a Sales Agreement (the “Sales Agreement”) with Cowen and Company, LLC as agent (“Cowen”) pursuant to which the Company may issue and sell shares of its common stock, $0.0001 par value per share, having an aggregate offering price of up to $100,000,000 (the “Shares”), from time to time through Cowen (the “Offering”). On February 28, 2022, the Company filed a prospectus supplement with the Securities and Exchange Commission in connection with the Offering (the “Prospectus Supplement”) under its existing Registration Statement on Form S-3 (File No 333-260895), which became effective on November 18, 2021 (the “Registration Statement”).

Upon delivery of a placement notice and subject to the terms and conditions of the Sales Agreement, Cowen may sell the Shares by any method permitted by law deemed to be an “at the market offering” (the “Offering”) as defined in Rule 415(a)(4) promulgated under the Securities Act of 1933, as amended (the “Securities Act”), including sales made directly on or through The Nasdaq Global Select Market or on any other existing trading market for the Company’s common stock.

The Company will designate the maximum amount of common stock to be sold through Cowen in any placement under the Offering. Subject to the terms and conditions of the Sales Agreement, Cowen has agreed to use its commercially reasonable efforts to sell on the Company’s behalf all of the Shares of common stock requested to be sold by the Company. The Company may instruct Cowen not to sell common stock if the sales cannot be effected at or above a price designated by the Company in a placement notice. The Company or Cowen may suspend the offering of the Shares being made through Cowen under the Sales Agreement upon proper notice to the other party. The Company and Cowen each have the right, by giving written notice as specified in the Sales Agreement, to terminate the Sales Agreement in each party’s sole discretion at any time.

The Sales Agreement provides that Cowen will be entitled to aggregate compensation for its services up to 3% of the gross sales price per share of all Shares sold through Cowen under the Sales Agreement. The Company has no obligation to sell any Shares under the Sales Agreement. The Company has agreed in the Sales Agreement to provide indemnification and contribution to Cowen against certain liabilities, including liabilities under the Securities Act.

The Shares will be offered and sold pursuant to the Registration Statement, and offerings of the Shares will be made only by means of the Prospectus Supplement. This Current Report on Form 8-K shall not constitute an offer to sell or the solicitation of any offer to buy the Shares, nor shall there be any offer, solicitation or sale of the Shares in any state in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of such state.

The foregoing description of the material terms of the Sales Agreement is qualified in its entirety by reference to the full text of the Sales Agreement, a copy of which is filed as Exhibit 1.1 hereto and is incorporated herein by reference.

The legal opinion of Wilmer Cutler Pickering Hale and Dorr LLP, counsel to the Company, relating to the Shares being offered is filed as Exhibit 5.1 to this Current Report on Form 8-K.