Dr Leidner on the Multivalent Vaccine DPV-001 in Advanced or Metastatic HNSCC

Rom S. Leidner, MD, medical oncologist, Providence Cancer Institute Franz Clinic, member, Earle A. Chiles Research Institute, Providence Health, discusses data from the phase 1 GITRVax trial (NCT04470024) evaluating the multivalent vaccine DPV-001 in combination with PD-1 inhibition with or without a GITR agonist in patients with advanced or metastatic head and neck squamous cell carcinoma (HNSCC).

DPV-001 is a novel microvesicle vaccine containing proteins for genes commonly overexpressed by cancer. It is enriched with short-lived proteins and defective ribosomal products, representing potential shared non-mutated alternative cancer neoantigens, which are also referred to as cancer’s dark matter. Preclinical studies showed increased therapeutic efficacy when DPV-001 was combined with anti–PD-1 and anti-GITR therapies, informing the rationale for this clinical trial.

In the study, 18 patients received DPV-001 with sequenced a novel PD-1 therapy, INCMGA00012. Nine of these patients also received the GITR agonist INCAGN01876 starting on day 1. The study included 9 patients who were naive to prior PD-1 therapy and 9 patients exposed to prior PD-1 therapy.

Leidner notes that the overall response rate (ORR) for patients with PD-1–naive disease was 55.5% (n = 5/9), and the ORR was 33.3% (n = 3/9) for patients previously treated with PD-1 therapy patients.

Notably, 2 of the responses in the PD-1–pretreated population were with DPV-001 and PD-1 therapy alone, pointing to the activity of DPV-001, Leidner explains. Additionally, 1 of the responders in the PD-1–refractory population also had a PD-L1 combined positive score of 0, and this patient had also previously received pembrolizumab (Keytruda) in combination with lenvatinib (Lenvima), as well as an HPV16 vaccine, Leidner continues. Two of the responses in the PD-1–exposed population were ongoing, he adds, noting that this includes patients who were HPV negative.

Although the patient population enrolled on the study was small, Leidner concludes that these early data are encouraging for a difficult-to-treat malignancy.