Pardo, D.A. Diaz

PURPOSE Hot flashes are a common side effect reported by men receiving androgen-deprivation therapy (ADT) for the treatment of prostate cancer. We sought to determine whether oxybutynin could improve hot flash symptoms in men with prostate cancer. PATIENTS AND METHODS Patients with prostate cancer receiving a stable regimen of ADT with at least 28 hot flashes per week were randomly assigned to receive either oxybutynin 2.5 mg twice daily, oxybutynin 5 mg twice daily, or matching placebo for 6 weeks. The primary end point was the change in patient-reported hot flash scores since baseline at 6 weeks. Additional outcomes included incidence of adverse events (AEs), changes since baseline in Hot Flash–Related Daily Interference Scale (HFRDIS) scores, and patient-reported symptoms. RESULTS Eighty-eight patients were enrolled, with the 81 participants eligible for final analysis reporting an average of 10.1 (standard deviation [SD], 5.55) hot flashes per day and an average daily hot flash score of 18.2 (SD, 13.5) included in final analysis. On average, patients on the placebo arm, 2.5 mg oxybutynin arm, and 5 mg oxybutynin arm had reductions in hot flashes/day of 2.15, 4.77 ( P = .02), and 6.89 ( P < .001), respectively. Daily hot flash scores for placebo, 2.5 mg oxybutynin, and 5 mg oxybutynin reduced by an average of 4.85, 9.94 ( P = .07), and 13.95 ( P = .002) points, respectively. No treatment-related grade 3+ AEs occurred. HFRDIS total scores improved by 14.2 and 20.7 points in the 2.5 mg ( P = .042) and 5 mg ( P < .01) oxybutynin arms, respectively, compared with a 3.1-point improvement with placebo. CONCLUSION Oxybutynin is superior to a placebo for the management of ADT-associated hot flashes in men with prostate cancer.

LBA12004 Background: Hot flashes are among the most common adverse events impacting quality of life reported by patients receiving androgen deprivation therapy (ADT) for the treatment of prostate cancer. Oxybutynin is an effective therapy for reducing frequency and severity of hot flashes in women. Pilot information supports that this drug may also benefit men with hot flashes related to ADT. Methods: Patients with prostate cancer receiving a stable regimen of ADT with at least 28 hot flashes per week were randomized to receive either oral oxybutynin 2.5 mg twice a day, oxybutynin 5 mg twice a day, or matching placebo doses for 6 weeks. The primary endpoint was the change in patient-reported hot flash scores (determined by multiplying the number of hot flashes by the mean hot flash severity [grade 0: none, 1: mild, 2: moderate, 3: severe, and 4: very severe]) from baseline to 6 weeks, as measured by a daily hot flash diary. A total of 87 patients provided 76% power to reject the null hypothesis of no between-arm mean difference in hot flash score reduction from baseline to 6 weeks, when comparing each oxybutynin arm to the combined placebo arms. This was based on a two-sided contrast estimated from a generalized linear mixed model, α= 0.10, intraclass correlation of 0.50, population standardized mean difference of 0.50, and 10% missing data rate. Results: 88 patients were accrued between 10/28/21 and 12/02/23. Six patients cancelled before starting treatment and one was ineligible, leaving 81 analyzed patients with a median age of 68. Baseline characteristics were balanced between arms with patients reporting an average of 10.15 (SD = 5.55) hot flashes per day and an average daily hot flash score of 18.23 (SD = 13.48) at enrollment. On average, patients on the placebo arm, low dose oxybutynin arm, and high dose oxybutynin arm had reductions of 2.15, 4.77, and 6.89 hot flashes/day, respectively. Compared to placebo arm patients, high dose oxybutynin arm patients had a greater reduction in hot flashes/day (p < 0.001), as did low dose oxybutynin arm patients (p = 0.02). Daily hot flash scores for the same three protocol arms reduced by an average of 4.85, 9.94, and 13.95 points, respectively. Compared to placebo arm patients, high dose oxybutynin arm patients had a greater reduction in daily hot flash scores (p = 0.002), as did low dose oxybutynin arm patients (p = 0.07). No treatment-related grade 3+ adverse events occurred. The most commonly reported oxybutynin-related grade 2 adverse event was dry mouth. Conclusions: Oxybutynin is superior to a placebo for the management of hot flashes in men associated with androgen deprivation therapy and appears to be well tolerated. Support: UG1CA189823; https://acknowledgments.alliancefound.org . Clinical trial information: NCT04600336 .

4500 Background: Trastuzumab is a monoclonal antibody against human epidermal growth factor receptor 2 (HER2). The primary objective of RTOG 1010 was to determine if trastuzumab increases disease-free survival (DFS) when combined with trimodality treatment for patients with HER2 overexpressing esophageal adenocarcinoma. Methods: This open label, randomized phase III trial included patients with newly diagnosed stage T1N1-2, T2-3N0-2 adenocarcinoma of the esophagus involving the mid, distal, or esophagogastric junction and up to 5cm of the stomach. All patients received chemotherapy (C) of paclitaxel, 50mg/m2 and carboplatin AUC = 2, weekly for 6 weeks, with radiation (XRT: 3D-CRT or IMRT, 50.4 Gy in 28 fractions) followed by surgery. Patients were randomized 1:1 to receive weekly trastuzumab 4mg/kg week 1 then 2mg/kg/weekly x 5 during CXRT then 6 mg/kg for 1 dose prior to surgery and 6mg/kg every 3 weeks for 13 treatments after surgery. HER2 status was determined by IHC and gene amplification by FISH. With a 2-sided alpha of 0.05, 162 DFS events provide 90% power to detect a signal for an increase in median DFS from 15 to 25 months. DFS and overall survival (OS) were estimated by the Kaplan-Meier method. and arms were compared using the log rank test. The Cox proportional hazards model was used to analyze treatment effect. Results: 571 patients were entered for assessment of HER2 expression, 203 HER2+ patients randomized. The median follow-up for alive patients is 5.0 years. The estimated 2, 3, and 4-year DFS (95% CI) for the CXRT +trastuzumab arm were 41.8% (31.8%, 51.7%), 34.3% (24.7%, 43.9%), and 33.1% (23.6%, 42.7%), respectively, and for the CXRT arm were 40.0% (30.0%, 49.9%), 33.4% (23.8%, 43.0%), and 30.1% (20.7%, 39.4%), respectively; log-rank p = 0.85. The median DFS time is 19.6 months (13.5-26.2) for the CXRT +trastuzumab arm compared to 14.2 months (10.5-23.0) for the CXRT arm. The hazard ratio (95% CI) comparing the DFS of CXRT+trastuzumab arm to the CXRT arm was 0.97 (0.69, 1.36). The median OS time was 38.5 months (26.2-70.4) for the CXRT+trastuzumab arm compared to 38.9 months (29.0-64.5) for the CXRT arm, hazard ratio (95% CI): 1.01 (0.69, 1.47). There was no statistically significant increase in treatment-related toxicities with the addition of trastuzumab including no increase in cardiac events. Conclusions: The addition of trastuzumab to trimodality treatment did not improve DFS for patients with HER2 overexpressing esophageal adenocarcinoma. Supported by NCI grants U10CA180868, UG1CA189867, U10CA180822 and Genentech. Clinical trial information: NCT01196390 .