Precigen, Inc. announced that the US Food and Drug Administration (FDA) has cleared the Investigational New Drug (IND) application to initiate a Phase I clinical trial of Precigen's PRGN-2012, a first-in-class, investigational off-the-shelf (OTS) AdenoVerse immunotherapy in adult patients with recurrent respiratory papillomatosis (RRP). RRP is a rare, difficult-to-treat and sometimes fatal neoplastic disease of the upper and lower respiratory tracts caused by human papillomavirus (HPV) type 6 (HPV 6) or HPV type 11 (HPV 11). 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 large payload capacity. In preclinical models, PRGN-2012 has demonstrated strong and specific immune response against HPV 6 and HPV 11. The Phase I study will follow 3+3 dose escalation of PRGN-2012 as an adjuvant immunotherapy following standard-of-care surgical removal of visible papillomatosis disease. Patients will receive up to four injections of PRGN-2012. The primary objective of the study is to determine safety and tolerability and recommended Phase II dose (RP2D) of PRGN-2012. The study will enroll 3 to 6 subjects at each dose level, and 12 patients will be treated at the maximum tolerated dose. PRGN-2012 is under development through a Cooperative Research and Development Agreement, or CRADA, with the Center for Cancer Research (CCR) at the National Cancer Institute (NCI). This CRADA has allowed Precigen to rapidly and cost-effectively advance PRGN-2012 to the clinic. The Phase I clinical study of PRGN-2012 will be led by Clint T. Allen, MD, Principal Investigator, Section on Translational Tumor Immunology, of the National Institute on Deafness and Other Communication Disorders (NIDCD), and Scott M. Norberg, DO, Assistant Research Physician, Genitourinary Malignancies Branch, of CCR NCI.