Phase 2 trial of a DNA vaccine (pTVG-HP) and nivolumab in patients with castration-sensitive non-metastatic (M0) prostate cancer

• DOI: 10.1136/jitc-2023-008067
• Publication Date: 2023-12-15T07:07:31Z
• Authors: Douglas G McNeel; Hamid Emamekhoo; Jens C Eickhoff; Christos E Kyriak...; Ellen Wargowski; Tommaso P Tonelli; Laura E Johnson; Glenn Liu
• Keywords: Clinical endpoint; Prostatic acid phosphatase

Purpose We have previously reported that a plasmid DNA vaccine encoding prostatic acid phosphatase (pTVG-HP) had greater clinical activity when given in combination with pembrolizumab to patients metastatic, castration-resistant prostate cancer. The current trial was conducted evaluate vaccination PD-1 blockade, using nivolumab, early, recurrent (M0) Methods Patients M0 cancer were treated pTVG-HP (100 µg administered intradermally) and nivolumab (240 mg intravenous infusion) every 2 weeks for 3 months, then 4 1 year of total treatment. followed an additional off primary objectives safety complete prostate-specific antigen (PSA) response (PSA<0.2 ng/mL). Results 19 enrolled. No met the endpoint PSA response; however, 4/19 (21%) decline >50%. Median doubling times 5.9 months pretreatment, 25.6 on-treatment (p=0.001), 9.0 subsequent off-treatment. overall median radiographic progression-free survival not reached. Grade or events included adrenal insufficiency, fatigue, lymphopenia, increased amylase/lipase. 9/19 (47%) developed immune-related adverse effects (irAE). development irAE CXCL9 associated time. Quantitative NaF PET/CT imaging showed resolution subclinical lesions along new at each time point. Conclusions In this population, combining safe, immunologically active, prolonged disease progression, but did eradicate disease. suggested treatments targeting mechanisms resistance may be required eliminate tumors. Trial registration number NCT03600350 .