Trial Outcomes & Findings for Phase II Trial of Immunotherapeutic HPV Vaccine PRGN-2009 With Pembrolizumab Before Standard Treatment in Subjects With Newly Diagnosed HPV-Associated Oropharyngeal Cancer (NCT NCT05996523)

Phase II Trial of Immunotherapeutic HPV Vaccine PRGN-2009 With Pembrolizumab Before Standard Treatment in Subjects With Newly Diagnosed HPV-Associated Oropharyngeal Cancer

CD3+ tumor infiltrating T cells post treatment compared with pre-treatment reported with a 95% confidence interval assessed by multiplex CD3+ tumor infiltrating lymphocytes assessed by multiplex immunofluorescence from the surgical/ biopsy tissue collected pre- and post-treatment. The percentage of participants with doubling of baseline CD3+ tumor infiltrating lymphocytes will be provided as well as the 95% confidence interval. The CD3 cells are assessed by multiplex immunofluorescence in the biopsies. Doubling is the desired outcome.

Assess if PRGN-2009 plus pembrolizumab results in significantly prolonged survival at three years as compared to the expected 80% three-year historical survival in p16-positive oropharyngeal cancer (OPC) participants. Three-year overall survival will be measured using a Kaplan-Meier curve and will be compared descriptively with the historical benchmark. Participants who receive two doses of PRGN-2009 and the single dose of pembrolizumab and go on to receive standard definitive therapy will be evaluable for overall survival assessment.

Overall survival was assessed using the Kaplan-Meier method and is defined as the time from the date of first treatment to the date of death (any cause). Participants who receive two doses of PRGN-2009 and the single dose of pembrolizumab and go on to receive standard definitive therapy will be evaluable for overall survival assessment.

Number of treatment-related serious adverse events of Grades 1, 2, 3, 4 and/or 5 along with the AE term. Adverse events were assessed by the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. Grade 1 is mild. Grade 2 is moderate. Grade 3 is severe. Grade 4 is life-threatening. Grade 5 is death related to adverse event. All participants who receive any investigational treatment will be evaluable for safety and toxicity evaluations.

Percentage of 2-fold increase in CD3+ Tumor Infiltrating Lymphocytes (TILs) by multiplex immunofluorescence post-treatment compared to pre-treatment in participants receiving PRGN2009 plus pembrolizumab in this trial as compared to that in participants receiving PRGN2009 monotherapy in study NCT04432597. Results of the primary endpoint of this study (Proportion of 2-fold increase in CD3+ Tumor Infiltrating Lymphocytes (TILs) by multiplex immunofluorescence post-treatment compared to pre-treatment) were compared with the same in participants in trial NCT04432597 (PRGN-2009 monotherapy). The two percentages will be compared descriptively and reported with a 95% confidence interval.

Relapse free survival was assessed using the Kaplan-Meier method and is defined as the time from completion of standard chemoradiation to the date of disease recurrence or death (any cause) whichever comes first. Participants who receive two doses of PRGN-2009 and the single dose of pembrolizumab and go on to receive standard definitive therapy will be evaluable for relapse-free-survival assessment.

Here is the number of participants with serious and/or non-serious adverse events assessed by the Common Terminology Criteria for Adverse Events (CTCAE v5.0). A non-serious adverse event is any untoward medical occurrence. A serious adverse event is an adverse event or suspected adverse reaction that results in death, a life-threatening adverse drug experience, hospitalization, disruption of the ability to conduct normal life functions, congenital anomaly/birth defect or important medical events that jeopardize the patient or subject and may require medical or surgical intervention to prevent one of the previous outcomes mentioned. All participants who receive any investigational treatment will be evaluable for safety and toxicity evaluations.