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
2344 - Lung Cancer in Europe: strengthening policy responses to address unmet needs
Presenter: Mary Bussell
Session: Poster Display session 3
Resources:
Abstract
1359 - Curative treatment timelines for breast, colorectal, lung and prostate cancer: Implications for medical leave coverage
Presenter: Selina Wong
Session: Poster Display session 3
Resources:
Abstract
4433 - Acute Diagnostic Oncology Clinic: A Unique Primary Care-Oncology Service
Presenter: Abhijit Gill
Session: Poster Display session 3
Resources:
Abstract
3506 - THE NEW MUTATIONAL MODEL IN ONCOLOGY. What changes in welfare, clinical practice, research, and regulatory procedures
Presenter: Nicola Normanno
Session: Poster Display session 3
Resources:
Abstract
3350 - Selection of a set of quality indicators (QI) for oncological clinical pathway
Presenter: Aude Fourcade
Session: Poster Display session 3
Resources:
Abstract
4400 - Sustainable drug prices at market launch: policy proposals and their empirical evidence
Presenter: Nora Fanzen
Session: Poster Display session 3
Resources:
Abstract
4118 - Impact of financial considerations on French physicians’ prescription choices for advanced non-small cell lung cancer (NSCLC)
Presenter: Nathalie Olympios
Session: Poster Display session 3
Resources:
Abstract
1340 - The direct medical cost of breast cancer in a Belgian hospital
Presenter: Hannan Lemhouer
Session: Poster Display session 3
Resources:
Abstract
1863 - Does the healthcare system approaches cancer patients for using private services during diagnostic process?
Presenter: Karolina Osowiecka
Session: Poster Display session 3
Resources:
Abstract
2637 - Measuring financial toxicity of cancer in the Italian health care system: initial results of the patient reported outcome for Fighting Financial Toxicity of cancer project (proFFiT).
Presenter: Silvia Riva
Session: Poster Display session 3
Resources:
Abstract