PDS Biotechnology Corporation announced interim safety and immune response data for the first-in-human Phase 1/2 clinical trial evaluating PDS0301, a novel investigational tumor-targeting, antibody-conjugated Interleukin 12, in combination with current standard-of-care (SOC) chemotherapy, docetaxel, to treat metastatic castration sensitive (mCSPC) and castration resistant (mCRPC) prostate cancer. The data will be featured in an oral presentation by Ravi A. Madan, MD, Head, Prostate Cancer Clinical Research Section, Genitourinary Malignancies Branch, Center for Cancer Research of the National Cancer Institute, an Institute of the National Institutes of Health, at the 11th Annual Meeting of the International Cytokine & Interferon Society (Cytokines 2023) in Athens, Greece. Eighteen patients (11 with mCSPC and 7 with mCRPC) with a median age of 69 years (range 39-82) were evaluated for clinical activity and toxicity.

Three dose levels of PDS0301 (8.0 mcg/kg, 12.0 mcg/kg, and 16.8 mcg/kg) in combination with docetaxel (75 mg/m2) were administered every three weeks beginning with the second cycle of treatment. The dose-limiting toxicity (DLT) window spanned the 6 weeks after initiating docetaxel. While all doses of PDS0301 were well-tolerated, the 12.0 mcg/kg dose of PDS0301 with chemotherapy provided the best combination of immune response and tolerability.

Interim data highlights to be presented at Cytokines 2023 include: Decrease in PSA levels was seen in all patients at all three tested doses of PDS0301 and ranged from -4% to -100%; All doses of the combination were well-tolerated with one patient experiencing Grade 4 neutropenia; Administration of the combination was associated with decreases in T reg cells and increases in activated natural killer (NK) cells, memory CD8 T cells, proliferating CD4 and CD8 T cells and cytokines INF-? and Interleukin 10 (IL-10); The changes in immune responses with the combination were independent of the PDS0301 dose.