Poseida Therapeutics Presents Preliminary Results from Phase 1 Trial of P-PSMA-101 at the 6th Annual CAR-TCR Summit

Encouraging data confirming activity in a solid tumor indication presented on first nine patients at low dose cohorts in ongoing autologous CAR-T trial in metastatic castrate-resistant prostate cancer

Three patients showed a greater than 50% decline in prostate-specific antigen (PSA) and concordant PSMA-PET imaging results, including one patient at lowest dose with evidence of complete tumor elimination

Favorable safety profile with modest overall rates of CRS and no neurotoxicity observed

Company to host webcast today to further review results at 11:00am ET

SAN DIEGO, Aug. 31, 2021 /PRNewswire/ — Poseida Therapeutics, Inc. (Nasdaq: PSTX), a clinical-stage biopharmaceutical company utilizing proprietary genetic engineering platform technologies to create cell and gene therapeutics with the capacity to cure, today announced preliminary results from its Phase 1 clinical trial of P-PSMA-101, the Company’s solid tumor autologous CAR-T product candidate to treat patients with metastatic castrate-resistant prostate cancer (mCRPC). These data will be presented at the 6th Annual CAR-TCR Summit virtual meeting at 10:00am ET today in a presentation entitled, “P-PSMA-101 is a High-Tscm Autologous CAR-T Targeting PSMA Producing Exceptionally Deep and Durable Responses in Castration-Resistant Metastatic Prostate Cancer.”

“We are excited about the preliminary data from our Phase 1 trial of P-PSMA-101, which provides further evidence of the effectiveness of our CAR-T platform for solid tumor cancers,” said Eric Ostertag, M.D., Ph.D., Chief Executive Officer of Poseida, who will present at the CAR-TCR Summit. “To date, other CAR-T therapeutics have not had much success outside of hematologic malignancies. The deep and durable responses in our trial demonstrate that CAR-T products have the potential to work well against solid tumors, even at low doses, when using the appropriate technology platform.”