Precigen Announces Positive Phase 1 Data for PRGN-3005 Autologous UltraCAR-T® Cells Manufactured Overnight for Infusion Next Day to Advanced Stage Platinum Resistant Ovarian Cancer Patients

GERMANTOWN, Md., June 5, 2023

GERMANTOWN, Md., June 5, 2023 /PRNewswire/ -- Precigen, Inc. (Nasdaq: PGEN), a biopharmaceutical company specializing in the development of innovative gene and cell therapies to improve the lives of patients, today presented positive data at the 2023 American Society of Clinical Oncology (ASCO) Annual Meeting from the Phase 1 portion of the Phase 1/1b clinical study evaluating safety and efficacy of PRGN-3005 UltraCAR-T^® in advanced stage platinum resistant ovarian cancer patients (Abstract# 5590). The presentation was delivered by John B. Liao, MD, PhD, Cancer Vaccine Institute, University of Washington Medicine, and a lead investigator for the PRGN-3005 clinical trial.

"We are pleased with the results of the Phase 1 study which demonstrate a favorable safety profile for PRGN-3005 UltraCAR-T. Our UltraCAR-T therapies continue to be well-tolerated with no dose limiting toxicities across our clinical stage UltraCAR-T portfolio," said Helen Sabzevari, PhD, President and CEO of Precigen. "At this early stage, we are encouraged that patients in the IV plus lymphodepletion arm showed stable or partial response in 90% of the individual target lesions, and that the case study presented demonstrated that the repeat dosing further decreased tumor burden. UltraCAR-T is the only CAR-T platform that has demonstrated the ability to expand and persist and show a reduction in tumor burden and lesions with low doses of UltraCAR-T cells in this heavily pretreated ovarian cancer patient population. We are currently underway in the Phase 1b dose expansion study at Dose Level 3 via IV infusion with lymphodepletion and incorporating repeat dosing."

"Ovarian cancer symptoms are not always obvious and it is frequently diagnosed at an advanced stage where cancer has spread to distant parts of the body, which results in historically poor outcomes," said Mary L. (Nora) Disis, MD, faculty member at the University of Washington and Fred Hutchinson Cancer Research Center and one of the lead investigators for the PRGN-3005 study. "The patients enrolled were heavily pretreated with a median of 8 or more prior lines of therapy and had significantly advanced stage disease with a high baseline tumor burden and distant metastases. PRGN-3005 resulted in a decrease in tumor burden in 67% of patients who received just one IV infusion following lymphodepletion. We are encouraged by the expansion, persistence and activity of the UltraCAR-T cells manufactured using the overnight process in this heavily pre-treated population of the patients, and in view of the favorable safety profile and preliminary activity, we are looking forward to utilizing PRGN-3005 cells in patients with fewer prior lines of therapy for their disease."

PRGN-3005 UltraCAR-T is an autologous chimeric antigen receptor T (CAR-T) cell therapy manufactured using non-viral gene delivery and is under investigation for the treatment of patients with advanced, recurrent platinum resistant ovarian, fallopian tube or primary peritoneal cancer.

PRGN-3005 utilizes Precigen's transformative UltraCAR-T therapeutic platform, which eliminates ex vivo expansion and reduces manufacturing time to allow for rapid next day administration of UltraCAR-T cells following non-viral gene transfer. PRGN-3005 UltraCAR-T is a multigenic CAR-T cell investigational therapy utilizing Precigen's advanced non-viral gene delivery system to co-express a chimeric antigen receptor, membrane-bound interleukin‐15 (mbIL15), and a kill switch for better precision and control.

Conducted in collaboration with the University of Washington and Fred Hutchinson Cancer Research Center, the Phase 1 study has completed dose escalation, which evaluated the safety and efficacy of PRGN-3005 administered either via intraperitoneal (IP) or intravenous (IV) infusion, in the absence of lymphodepletion (LD) or IV following lymphodepletion with cyclophosphamide only (clinical trial identifier: NCT03907527).