Vaccine-Chemoradiotherapy Combo Produces 100% Clinical Response in Advanced Cervical Cancer

A 100% clinical response rate was observed in patients with stage IB3 to IVA cervical cancer who were given PDS0101 and chemoradiotherapy, according to preliminary results of the phase 2 IMMUNOCERV trial (NCT04580771).

In 100% (n = 9) of patients treated with PDS0101 plus chemoradiotherapy, there was a clinical response with tumor shrinkage of more than 60% which was evaluated at mid-point with an MRI. In 89% of patients, a complete response was observed, with 1 patient showing residual disease, and another having died from an event unrelated to treatment.

“The updated data from the ongoing IMMUNOCERV phase 2 clinical trial presented during Society for Immunotherapy of Cancer 2022 add to the encouraging results observed thus far and suggest that the combination of PDS0101 and chemoradiotherapy may hold promise as a potential first-line treatment for advanced, localized cervical cancer,” Frank Bedu-Addo, PhD, CEO of PDS Biotech, said in a company-issued press release announcing the results. “Importantly, 100% of patients responded to treatment with the combination of PDS0101 and chemoradiotherapy. We believe this study also provides further confirmation that PDS0101 induces the right type, quality, and potency of killer T cells in humans that may translate to effective treatment of cervical cancer. We look forward to the continued advancement of the IMMUNOCERV phase 2 clinical trial and the opportunity to report updated data during 2023.”

Of 17 patients enrolled onto the trial, 9 completed the 170-day post-treatment PET CT scan which was used to assess their cancer. Moving forward, a total of 35 patients are estimated to be enrolled. PDS0101 is a type of vaccine designed to assist the immune system in responding to HPV16-infected cervical cancer cells.

The primary endpoint was to determine the rate of grade 3 or higher acute toxicities, with secondary endpoints assessing the rate of complete metabolic response, rate of 90% or more tumor volume reduction, rates of local control, rates of progression-free survival, and rates of overall survival (OS).

Treatment included radiotherapy of 1 hour per day, 5 days a week for 5 to 7 weeks with receipt of cisplatin intravenously over 4 hours each week during the 5 weeks of treatment. PDS0101 was given subcutaneously on days –10, 7, 28, 49, and 170.

In those treated with the combination, the 1-year disease-free survival and OS was 89%. An increase of HPV16-specific CD38 T cells was observed in those treated with PDS0101. This increase is thought to be correlated with tumor cell death in which cytotoxic CD8-positive T cells help to mediate antigen-specific immunity.

Of note, the toxicity has remained low-grade with local injection site reactions.

If patients had newly diagnosed or histologic disease; an ECOG performance status of 0 to 2; alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, or total bilirubin of less than 2-fold of the upper limit of normal they were included in the study. Patients also must have a creatine level of 1.5 mg/dL or less, an electrocardiogram with no significant findings, and an absence of current malignancies at other sites to be included in the trial.

Patients who have human immunodeficiency infection, prior diagnosis of hepatitis B or C, history of a significant autoimmune disease, or a serious concomitant disorder were excluded from the trial. Those who had receipt of immunotherapy within 4 weeks of treatment, chronic systemic therapy within 7 days of treatment, and history of a previous human papillomavirus vaccination, with exception to Silgard, Cervarix, and Gardasil, were also excluded.

Reference

PDS Biotech announces 100% clinical response in cervical cancer patients in preliminary data from IMMUNOCERV phase 2 clinical trial. News release. PDS Biotech. November 14, 2022. Accessed November 14, 2022. https://bit.ly/3trbOiY