Abstract 3142
Background
Preclinical studies have demonstrated that a DNA vaccine encoding the androgen receptor ligand-binding domain (AR LBD) can elicit CD8+ T cells specific for the AR LBD, delay disease progression and prolong survival of prostate tumor-bearing animals. Vaccination of tumor-bearing mice treated with androgen deprivation (AD) led to a delay in the emergence of castration-resistant disease. This same DNA vaccine (pTVG-AR, MVI-118) was evaluated in a phase I clinical trial in men with metastatic prostate cancer (mPC) on AD therapy.
Methods
40 patients with mPC, within 6 months of beginning standard AD therapy, were randomly assigned to receive pTVG-AR on one of two different treatment schedules, and with or without GM-CSF used as an adjuvant. Ten total vaccinations were given over 1 year, and patients were followed for 18 months. The primary objectives were safety and immune activity. Secondary objectives were to evaluate different schedules, the requirement for GM-CSF, and whether treatment was associated with PSA progression-free survival (PSA PFS).
Results
Between 2015 and 2017, 40 patients were enrolled at 3 centers. 27 patients completed treatment and 18 months of follow-up. Eleven patients (28%) had a PSA progression event. No grade 3 or 4 adverse events were observed. Samples from 30 patients were available for immune analysis. 14/30 (47%) developed Th1 biased immunity to the AR LBD as determined by IFNγ or granzyme B ELISPOT that was detectable at least twice after beginning treatment. Differences in immune responses were observed with different schedules, but not with GM-CSF adjuvant. Patients who developed immunity had a significantly prolonged PSA PFS compared to patients without immunity (HR = 0.18, 95% CI: 0.04-0.92, p = 0.040).
Conclusions
This trial showed that pTVG-AR was safe and immunologically active in patients with mPC, and identified a preferred schedule of administration. Association between immunity and PSA PFS suggests treatment may delay the time to castration resistance, similar to observations in preclinical studies. Future studies will evaluate pTVG-AR in earlier stages of disease, and in combination with other agents.
Clinical trial identification
NCT02411786.
Editorial acknowledgement
Legal entity responsible for the study
Douglas McNeel.
Funding
Madison Vaccines, Inc.
Disclosure
D.G. McNeel: Advisory / Consultancy, Research grant / Funding (self), Travel / Accommodation / Expenses, Shareholder / Stockholder / Stock options, Licensing / Royalties, Officer / Board of Directors: Madison Vaccines Inc; Research grant / Funding (institution): BMS; Research grant / Funding (institution): Janssen; Research grant / Funding (institution): Novartis; Research grant / Funding (institution): Merck. R. Lesniewski: Leadership role, Travel / Accommodation / Expenses, Shareholder / Stockholder / Stock options, Full / Part-time employment, Officer / Board of Directors: Madison Vaccines Inc. B. Olson: Licensing / Royalties: Madison Vaccines Inc. C. Kyriakopoulos: Research grant / Funding (institution): Madison Vaccines Inc. All other authors have declared no conflicts of interest.
Resources from the same session
4900 - Molecular profiling and prognostic significance of TP53 mutations in Diffuse Large B Cell Lymphoma: identifying a high-risk subgroup
Presenter: Yuan-Kai Shi
Session: Poster Display session 3
Resources:
Abstract
3809 - Differential expression of various miRNAs in Pediatric Cytogenetically Normal Acute Myeloid Leukemia (CN-AML)
Presenter: Vikas Gaur
Session: Poster Display session 3
Resources:
Abstract
4750 - Circulating tumour cells in head and neck and non-small cell lung cancer
Presenter: Kenneth O'Byrne
Session: Poster Display session 3
Resources:
Abstract
3704 - OX40/OX40L protein expression in Non-small cell lung cancer and its role in clinical outcome and relationships with other immune biomarkers
Presenter: Xiaoshen Zhang
Session: Poster Display session 3
Resources:
Abstract
2235 - Effect of Serum Survivin on Survival among Non-Small Cell Lung Cancer Patients; NCI Experience
Presenter: Reham Rashed
Session: Poster Display session 3
Resources:
Abstract
2788 - Enhanced performance of prognostic estimation from TCGA RNAseq data using transfer learning.
Presenter: Helene Vanacker
Session: Poster Display session 3
Resources:
Abstract
4689 - Analysis of Circulating Tumor DNA for Early Relapse Detection in Stage III Colorectal Cancer After Adjuvant Chemotherapy
Presenter: Samuel Jacobs
Session: Poster Display session 3
Resources:
Abstract
1454 - Ascites-derived circulating microRNAs as potential diagnostic biomarkers of gastric cancer-associated malignant ascites
Presenter: Hye Sook Han
Session: Poster Display session 3
Resources:
Abstract
5574 - Results from TRIO030, a Pre-Surgical Tissue-Acquisition Study to Evaluate Molecular Alterations in Human Breast Cancer Tissue Following Short-Term Exposure to the Androgen Receptor Antagonist Darolutamide
Presenter: Hsiao-Wang Chen
Session: Poster Display session 3
Resources:
Abstract
1787 - JMJD2A is a novel epigenetic factor of chemotherapeutic susceptibility in gastric cancer
Presenter: Yasushi Sato
Session: Poster Display session 3
Resources:
Abstract