On February 17, 2022, Zosano Pharma Corporation received a response letter from the U.S. Food and Drug Administration with regard to the Company's January 18, 2022 resubmission of the 505(b)(2) New Drug Application for M207 (zolmitriptan microneedle system) (“M207 NDA”). The response letter stated that the FDA did not consider the resubmitted M207 NDA to be a complete response to the deficiencies identified in the FDA's October 19, 2020 Complete Response Letter, and that the FDA will not begin substantive review of the application until a complete response is received. Among other things, the FDA's response letter stated that the Company's strategy for establishing a pharmacokinetic (“PK”) bridge to Zomig Nasal Spray 5 mg (“Zomig NS”) by relying primarily on data from the Company's recently completed Phase 1 PK study (“Study CP-2021-001”) was not acceptable, due in part to differences between the design of Study CP-2021-001, which compared the PK of M207 to two sequential doses of 5 mg Zomig NS, and the criteria for re-dosing set out in the labeling instructions for 5 mg Zomig NS.

The FDA's response letter described alternative methods through which the Company may establish a PK bridge to 5mg Zomig NS, including: (i) by demonstrating bioequivalence to Zomig NS using standard criteria for all PK exposure metrics, including through a combination of relevant PK data and modeling or simulation procedures; or (ii) by conducting a relative bioavailability study in healthy volunteer subjects.