Telemedicine-enabled clinical trial of metformin in patients (pts) with biochemically-recurrent prostate cancer (PCa).

Abstract

243Background: Clinical trials are critical to informing cancer care but are hampered by slow accrual and suboptimal generalizability, both contributed to by poor geographic accessibility. We previously reported that > 50% of the US population resides > 1 hour from the nearest PCa clinical trial site (Galsky, JAMA Int Med, 2015). We sought to test the feasibility of replacing on-site study visits with telemedicine visits in a prospective clinical trial. Methods: Castration-naïve non-metastatic pts with PCa and a rising PSA after local therapy were eligible. Pts required a single on-site visit for enrollment. Treatment consisted of metformin 850 mg QD x 1 month followed by 850 mg BID x 5 months. Telemedicine visits were conducted monthly using a HIPAA-compliant smartphone application. The primary objective was to determine feasibility defined as completion of all eligible telemedicine visits by > 2/3 enrolled pts; pts were ineligible for future telemedicine visits if treatment discontinued early for toxicity or disease progression. Secondary objectives included safety, % patients with ≤ 20% PSA rise at 6 months, quality of life, and patient satisfaction. Results: 15 pts were enrolled, median age 68 (range, 57, 83), one-way driving time 1.3 hours (range, 0.2-2.8), Gleason score 7 (range, 6, 9), and pre-study PSA 4.1 (range, 0.52, 31.7). The 6 month course of metformin was completed by 11/15 (73%) pts; 2 discontinued early due to rising PSA, 1 due to adverse event (AE), and 1 remains on study. Excluding 1 pt still on study, 14/14 (100%; 95% CI 76, 100) pts completed all 78 eligible telemedicine visits. The most common AEs were diarrhea (grade 1 = 60%) and fatigue (grade 1 = 20%); 1 pt experienced grade ≥ 3 AE (dehydration). The 6-month PSA was ≤ 20% baseline in 1 pt; median % PSA change at last televisit was +52.8% (range, -3.0, +318.8). Quality of life and pt satisfaction will be reported at the meeting. Conclusions: To our knowledge, this is the first ever interventional oncology clinical trial conducted via telemedicine. Telemedicine-enabled trials are feasible and may overcome barriers to trial participation. Metformin was generally well tolerated but associated with minimal anti-PCa activity as measured by PSA. Clinical trial information: NCT02376166.