On June 2, 2025 PDS Biotechnology Corporation (Nasdaq: PDSB) ("PDS Biotech" or the "Company"), a late-stage immunotherapy company focused on transforming how the immune system targets and kills cancers, reported publication of three Versamune HPV abstracts now available on the 2025 American Society of Clinical Oncology (ASCO) (Free ASCO Whitepaper) Annual Meeting website (Press release, PDS Biotechnology, JUN 2, 2025, View Source [SID1234653620]). These abstracts summarize Versamune HPV (PDS0101) studies that were presented during the Head and Neck Cancer Poster Session taking place May 30-June 3, 2025, in Chicago, Illinois.

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It is estimated that over 50% of head and neck squamous cell carcinoma (HNSCC) cases in the US are HPV16-positive.1 HPV-positive and HPV-negative HNSCC are two distinct diseases with different underlying causes, origin, risk factors, and contributions to the development of HNSCC. Multiple types of HPV are associated with HSNCC, and those cases are commonly identified with a p16 histochemistry test and referred to as p16-positive. A p16-positive test result suggests that the patient’s cancer may be due to any of the over 100 types of HPV. PDS Biotech is specifically addressing HNSCC related to HPV type 16 (HPV16), the most carcinogenic type of HPV. 2 HPV16-positive HNSCC has been identified as a rapidly growing and severe medical need.3,4 HPV16 is a specific type of HPV that must be confirmed using a polymerase chain reaction (PCR) test.

PDS Biotechnology’s trial differs from the other ongoing Phase 3 clinical trials addressing 1L r/m HNSCC based on its specific HPV16-positive HNSCC target population and its therapeutic approach.

Phase 3 Development

EGFR Bispecific Antibodies

PDS Biotechnology
Therapeutic Approach

Blocking antibodies targeting EGFR and a second receptor

HPV16-targeted T cell immunotherapy
Treated Populations

Predominantly HPV-negative and no confirmed HPV16-positive HNSCC patients#

100% HPV16-positive HNSCC*
Mechanism of Action

Inhibition of EGFR signaling and either LGR5 or TGF-β

Promotes multi-functional CD4 (helper) and CD8 (killer) T cell response targeting HPV16 E6 and E7 expressing tumors
#P16 histochemistry test to determine infection with any of > 100 types of HPV
*Confirmatory PCR test for HPV16-positive specific infection

Kevin Harrington, M.D., Ph.D. of The Institute of Cancer Research in the United Kingdom stated, "HPV-positive HNSCC is today seen as a different disease from HPV-negative HNSCC. HPV-positive HNSCC has different biological characteristics and requires a more targeted approach that treats the underlying HPV integration and persistence into the patient’s tumor DNA. Cytotoxic drugs and the EGFR inhibitor cetuximab have not worked as well in HPV-positive HNSCC to date."

HPV16 has been reported to suppress the immune system’s ability to respond to the virus, resulting in more difficult-to-treat and non-immunogenic tumors.5 At least two studies have compared patients with HPV16-positive HNSCC with p16-positive patients (excluding HPV16) and patients with HPV-negative HNSCC, and shown patients with HPV16-positive HNSCC to have significantly worse survival prognosis than other p16-positive HNSCC, and in an advanced oral cancer study, patients with HPV16-positive HNSCC had significantly worse survival than patients with HPV-negative HNSCC.6,7

To accurately identify and appropriately treat patients with HPV16-positive HNSCC, the U.S. Food and Drug Administration (FDA) recommended that a companion diagnostic be developed and included in the ongoing VERSATILE-003 Phase 3 trial.

VERSATILE-002: Overall Survival of HPV16-Positive Recurrent/Metastatic Head and Neck Squamous Cell Carcinoma Patients Treated with T Cell Stimulating Immunotherapy PDS0101 and Pembrolizumab (Abstract #6037) – Poster Presentation. June 2, 2025, 9:00 a.m.-12:00 p.m. CDT

The trial was performed across 31 sites in the US and Europe. Median follow-up time is 22.1 months (range 0.2-43.0 months), representing one of the most extended follow-up periods to date of subjects receiving treatment for HPV16-positive 1L r/m HNSCC.

Median overall survival (mOS) has remained steady at 30.0 months over the last 1.5 years, suggesting durability of the Versamune HPV-induced clinical responses. The lower limit of the 95% confidence interval for mOS has, however, increased from 18.4 months in 2023 to 23.9 months as the data has matured. All data are reported according to RECISTv1.1 criteria, requiring clinical responses on at least two consecutive tumor scans at least 4 weeks apart. Enrollment in the trial (n=53) is complete; 22 patients (including 3 still on treatment) continue to be followed for survival. No new safety signals have emerged.

Summary of results for Versamune HPV with pembrolizumab stratified by patient CPS status.

Versamune HPV (PDS0101) + Pembrolizumab (VERSATILE-002)

CPS ≥ 1
N=53 (100%)
CPS ≥ 20
N=21/53 (40%)
CPS 1-19
N=32/53 (60%)

Median Overall Survival (mOS)
30.0 months
(95% Confidence interval,
lower limit of 23.9 months,
upper limit not yet estimable
(NE))
39.3 months
(95% CI 30.0, NE)
26.1 months
(95% CI 15.3, NE)

Median Progression Free Survival (PFS)
6.3 months
(95% CI 2.8, 14.1)
14.1 months
(95% CI 2.1, NE)
5.1 months
(95% CI 2.2, 8.1)

Objective Response Rate (ORR)
19/53 (35.8%)
10/21 (47.6%)
9/32 (28.1%)

Tumor Shrinkage of 90-100%

11/53 (20.8%)
6/21 (28.6%)
5/32 (15.6%)

Disease Control Rate (DCR)

41/53 (77.4%)
17/21 (81.0%)
24/53 (75.0%)

Median Duration of Response (DoR)
21.8 months
(95% CI 11.5, NE)
NE
(95% CI 5.6, NE)
21.8 months
(95% CI 4.2, NE)
The longest published mOS reported to date with pembrolizumab monotherapy and combinations with pembrolizumab in patients with 1L r/m HNSCC and CPS ≥ 1 is 17.9 months8.

Jared Weiss, M.D., Section Chief of Thoracic and Head/Neck Oncology, Professor of Medicine at the University of North Carolina, and Principal Investigator of the VERSATILE-002 Phase 2 clinical trial, stated, "The mOS results are highly encouraging in patients with advanced HPV Type 16-positive HNSCC. This is great news for patients, and we are encouraged that mOS has remained durable over the last 1.5 years. We look forward to the randomized Phase 3 trial, which is the only ongoing registrational trial to specifically address this rapidly growing population of patients."

Dr. Kirk Shepard, M.D., Chief Medical Officer of PDS Biotech, continued, "We are very pleased with the overall survival (OS) results. As stated in a 2023 Journal of Clinical Oncology article authored by the FDA, OS is considered the gold standard for oncology approvals. The article discussed the discordance between ORR, PFS and OS. In recently published registrational 1L r/m HNSCC studies, improved ORR and PFS have not translated to improved OS. We look forward to the two interim survival data readouts from the ongoing Phase 3 study as well as the final OS results."