Precigen, Inc. announced that the US Food and Drug Administration (FDA) has agreed that the ongoing Phase 1/2 single arm study (NCT04724980) of the first-in- class investigational PRGN-2012 AdenoVerse(TM) immunotherapy for the treatment of recurrent respiratory papillomatosis (RRP) will serve as pivotal for the purpose of filing an accelerated approval request for licensure. The FDA also confirmed no additional randomized, placebo-controlled trial will be required to support submission of a biologics license application (BLA). Based on the FDA guidance, the Company plans to initiate a confirmatory study prior to submission of the BLA.

The FDA has confirmed that the current primary endpoint for the ongoing Phase 1/2 study, which is Complete Response rate (percentage of patients with no surgical interventions during the 12 months following treatment with PRGN-2012), along with an immunological surrogate marker demonstrating an induction of HPV-specific T cell responses following PRGN- 2012 treatment, is acceptable for the accelerated approval request. PRGN-2012 is an innovative therapeutic vaccine with optimized antigen design that uses Precigen's gorilla adenovector technology, part of Precigen's proprietary AdenoVerse platform, to elicit immune responses directed against cells infected with HPV 6 or HPV 11. Gorilla adenovectors have numerous advantages, including the ability for repeat administration, the inability to replicate in vivo, which may improve safety, and the ability to deliver a large genetic payload.

The FDA granted PRGN-2012 Breakthrough Therapy Designation and Orphan Drug Designation for the treatment of RRP. Data from the Phase 1 portion of the study showed that 50% of adult RRP patients (who had >=3 surgeries to treat the disease in the year prior to treatment) were "surgery-free" (Complete Response) after PRGN-2012 treatment during the 12 month follow-up. All complete responders continue to be surgery-free with a minimum follow-up of 18 months post- treatment.

Precigen has completed enrollment and dosing in the Phase 2 portion of the study (N=23) bringing the total number of enrolled patients to 35 at the recommended Phase 2 dose. Patient follow up is currently ongoing and data collection is anticipated to be completed by the second quarter of 2024.