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Late-Breaking Scientific Oral Presentations

Laryngology/Broncho-Esophagology

Session: Late Breaking Scientific Orals 2

PRGN-2012, a novel HPV-Targeted Immuno-Activator, induces complete and durable responses in recurrent respiratory papillomatosis patients

Sunday, October 12, 2025
8:12 AM - 8:18 AM EDT
Location: 107-108
Disclosure(s):
Scott M. Norberg, D.O.:

faculty for this accredited education activity has no relationship(s) with ineligible companies to disclose.

Gaetano Bonifacio, MD:

faculty for this accredited education activity has no relationship(s) with ineligible companies to disclose.

Clint T. Allen, MD:

faculty for this accredited education activity has no relationship(s) with ineligible companies to disclose.

Introduction: Recurrent respiratory papillomatosis (RRP) is a rare, chronic disorder caused by infection with human papillomavirus (HPV) type 6 or 11. RRP is associated with significant morbidity due to airway obstruction and managed with frequent ablative procedures leading to irreversible laryngotracheal scarring. PRGN-2012 is a novel HPV-Targeted Immuno-Activator engineered to generate HPV6/11-specific T-cell responses.

Methods: The pivotal trial (NCT04724980) evaluated PRGN-2012 in patients with RRP requiring ≥3 clinically-indicated interventions 12 months (m) prior to treatment. 12m follow-up (FU) data was reported and demonstrated that 4 subcutaneous injections of PRGN-2012 (5x10^11 particle units per injection; n=35) were well-tolerated, with no serious adverse events, no grade >2 treatment-related adverse events, and no early treatment discontinuations. The most common adverse events were injection-site reaction, fatigue, chills, fever, and myalgia.

Robust efficacy was observed following PRGN-2012 treatment, 51.4% (34.0 to 68.6; 95% CI) of patients achieving a Complete Response (CR), defined as no requirement for interventions in the 12m following treatment and 86% of patients experienced a decrease in interventions. Here we present data up to 36m of FU.

Results: As of March 20, 2025, median duration of FU for all 35 patients was 30.3m (5 – 36). No new safety events were observed during long-term FU.

Of 18 initial protocol-defined CRs, 15 (83%) remained in CR with median duration of FU of 34m (24-36). Median duration of CR has yet to be reached. 58% (39.1 to 75.5; 95% CI, n=31) and 83% (51.6 to 97.9; 95% CI, n=12) of evaluable patients did not require any interventions in year (Y) 2 and Y3 respectively. 90% and 91% of evaluable patients experienced a decrease in the number of interventions in Y2 and Y3 respectively compared to their 12m pre-treatment period.

Conclusions: These data demonstrate that patients treated with PRGN-2012 either maintained consistent CRs for at least 3 years or demonstrated a reduction in the need for clinically indicated interventions following recurrence with excellent long-term safety.

    Presenting Author(s)

  • SN

    Scott M. Norberg, D.O.

    Head, Solid Tumor Cellular Therapy Group
    Center for Immune-Oncology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
    Bethesda, MD, United States

    Disclosure(s):

    faculty for this accredited education activity has no relationship(s) with ineligible companies to disclose.

  • GB

    Gaetano Bonifacio, MD

    Vice President and Head of Medical Affairs
    Precigen, Inc. Germantown, Maryland, USA
    Collegeville, PA, United States

    Disclosure(s):

    faculty for this accredited education activity has no relationship(s) with ineligible companies to disclose.

  • Clint T. Allen, MD

    Tenured Investigator
    NIH
    Bethesda, MD, United States

    Disclosure(s):

    faculty for this accredited education activity has no relationship(s) with ineligible companies to disclose.

    • Co-Author(s)

  • SN

    Scott M. Norberg, D.O.

    Head, Solid Tumor Cellular Therapy Group
    Center for Immune-Oncology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
    Bethesda, MD, United States

    Disclosure(s):

    faculty for this accredited education activity has no relationship(s) with ineligible companies to disclose.

  • PV

    Premkumar Vummidi Giridhar, PhD

    Senior Clinical Trial Manager
    Precigen, Inc. Germantown, Maryland, USA
    Germantown, MD, United States

    Disclosure information not submitted.

  • RS

    Roshanak Semnani, Ph.D.

    Executive Director, Translational Research
    Precigen, Inc. Germantown, Maryland, USA, United States

    Disclosure information not submitted.

  • GB

    Gaetano Bonifacio, MD

    Vice President and Head of Medical Affairs
    Precigen, Inc. Germantown, Maryland, USA
    Collegeville, PA, United States

    Disclosure(s):

    faculty for this accredited education activity has no relationship(s) with ineligible companies to disclose.

  • AL

    Amy R. Lankford, PhD

    SVP, Head of Clinical Operations and Regulatory Affairs
    Precigen, Inc. Germantown, Maryland, USA
    Germantown, MD, United States

    Disclosure information not submitted.

    • Senior Author(s)

  • Clint T. Allen, MD

    Tenured Investigator
    NIH
    Bethesda, MD, United States

    Disclosure(s):

    faculty for this accredited education activity has no relationship(s) with ineligible companies to disclose.