A randomized phase II trial of personalized peptide vaccine plus low dose estramustine phosphate (EMP) versus standard dose EMP in patients with castration resistant prostate cancer

3 Background: We previously developed MHC class I restricted peptide vaccines for prostate cancer and carried out a phase 1 trial for castration resistant prostate cancer (CRPC) patients to assess safety and immunological evaluation. In the present study, we conducted a randomized phase 2 trial to evaluate the efficacy of peptide vaccination therapy for chemotherapy-naive CRPC patients. Methods: Early-stage CRPC (PSA<10ng/ml) patients positive for HLA-A02 or A24 or A3 super family were randomized into two treatment groups; peptide vaccine with low dose (1mg/day) dexamethasone (Dx) versus low dose Dx alone. Patients were vaccinated subcutaneously with 3 mg of selected peptides (max. 4 kinds) 6 times at two weeks interval. Dx 1mg/day p.o. was started on the first day of peptide vaccination. Toxicity was assessed monthly, and immunological responses such as cytotoxic T lymphocyte activity and clinical responses were evaluated every 3 months. The primary endpoint of this study is progression-free survival including serum PSA. Secondary endpoints are overall survival and safety. Results: A total of 83 chemotherapy-naive CRPC patients were selected for this trial. Of these 10 patients were excluded due to HLA type mismatch and exclusion criteria. 73 patients were enrolled and randomized; 37 in the vaccine treatment group and 36 in the Dx group. One patient in the Dx group self-withdrew from the study immediate after the randomization. Median time to PSA failure in the vaccine group was significant longer than the Dx group; 602 days vs 210 days, p<0.001 (Table). Conclusions: These findings suggest that combination therapy of peptide vaccines and low dose dexamethasone may be a promising tool for chemotherapy-naive CRPC patients. Clinical trial information: UMIN000000959.[Table: see text]

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The study of the treatment efficacy in metastatic castration-resistant prostate cancer of low dose abiraterone with food.

Journal of Clinical Oncology ◽

10.1200/jco.2020.38.15_suppl.e17571 ◽

2020 ◽

Vol 38 (15_suppl) ◽

pp. e17571-e17571

Author(s):

Kanta Makphanchareonkit ◽

Thitiya Sirisinha Dejthevaporn ◽

Dittapol Muntham ◽

Phichai Chansriwong

Keyword(s):

Quality Of Life ◽

Prostate Cancer ◽

Adverse Events ◽

Low Dose ◽

Standard Dose ◽

Abiraterone Acetate ◽

Castration Resistant Prostate Cancer ◽

Castration Resistant ◽

Psa Response

e17571 Background: Abiraterone acetate and prednisolone (AAP) + ADT has been approved for treatment metastatic castration-resistant prostate cancer (CRPC) in the standard dose 1,000 mg with fasting state. Data in Ramathibodi hospital showed patients who had treated with standard dose of Abiraterone acetate (AA); had PSA response 47.83%. Previous studies showed using low dose AA of 250 mg with food had the non-inferiority results in efficacy. AA was not be reimbursed in Thailand, so the ability to use a highly effective drug at a quarter of the dose, could help in patient accessibility to cancer treatments. We sought to test the hypothesis that low-dose AA with food would have the comparable activity in Thai CRPC patients in both of the pre-Docetaxel and post Docetaxel treatment groups, and exploring the quality of life (QOL) of these patients. Methods: An observational cohort enrolled newly diagnosed metastasis CRPC at Ramathibodi hospital from 1st Jan 2019 to 31st Dec 2019. Patients were assigned to AA (250mg) with actual daily life meal. We collected the data of serum PSA and the adverse events every 4 weeks for 4 months. The QOL data was collected with the EuroQoL (EQ-5D) questionnaire which were done at baseline and every 4 weeks. The primary end point was PSA response that defined as PSA decreased ≥ 50% from PSA level at baseline. The secondary endpoint were the depth of PSA change, QOL and adverse events by using Fisher's exact test and T-test. Results: 21 patients were enrolled. At 12 weeks, there were 11 patients (52.38%) achieved 50% PSA response and 6 patients (28.57%) achieved 90% PSA response. The adverse events occurred 23.8%, and mostly were mild grade. The adverse events were comparable with the historical data in standard dose of AA. Low dose AA has significantly shown the improvement in quality of life from baseline (p < 0.001), and especially the significant improvement in pre-Docetaxel subgroup. Conclusions: Low-dose AA with food has good efficacy in PSA response, adverse events and QOL. Moreover, low dose AA shows more efficacy especially in pre-Docetaxel mCRPC patients. Low dose AA may be helping in reducing cost of cancer care, enabling in delivering affordable cancer care and increasing value of treatment.

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