ASPIRE GCT: A single-arm, phase II clinical trial of aspirin to prevent venous thromboembolism in patients with advanced germ cell tumors receiving chemotherapy.

TPS624 Background: Advanced testicular/germ cell tumors (GCT) are highly curable with chemotherapy; however, patients with advanced GCT are at high risk for venous thromboembolism (VTE) during treatment. A role for thromboprophylaxis has not been established. Low-dose aspirin (ASA) is an inexpensive, widely available therapy that reduces VTE risk in orthopedic trauma, hip replacement, and multiple myeloma settings. ASPIRE-GCT aims to evaluate the 6-month VTE-free rate in patients with advanced GCT at high VTE risk who receive standard chemotherapy plus low-dose ASA. Methods: This investigator-initiated, single-arm, prospective phase II study evaluates the 6-month VTE-free rate among patients with advanced GCT at high VTE risk receiving cisplatin-based chemotherapy and ASA 81 mg daily for 6 months. Eligible patients are males aged 18–70 years with testicular, mediastinal, or retroperitoneal GCT (seminoma or non-seminoma) who will receive 3–4 cycles of BEP, EP, or VIP. Participants must have one of the following high-risk features: IGCCCG intermediate/poor risk, AJCC 8th edition Stage IIC or III, or a Khorana score of 2 or higher. Key exclusion: prior VTE, prior anticoagulation, or ASA contraindication. The primary endpoint tests the null hypothesis that the 6-month VTE-free rate is ≤65%, based on a historical VTE rate of 35% in this population. A 2-stage design is used with 13 participants enrolled in the first stage. If at least 9 of the 13 do not experience a VTE then up to 18 additional participants will be enrolled for a total of 31 evaluable patients. Based on a 1-sided alpha = 0.10 significance level, this sample size will provide at least 90% power assuming the true 6-month VTE-free rate is 85%. Secondary endpoints include major bleeding and clinically relevant non-major bleeding rates, relapse-free survival, and overall survival. This is the first prospective study evaluating prophylactic aspirin thromboprophylaxis in advanced GCT. Status: This study is actively accruing at the Advocate Health/Wake Forest Baptist Comprehensive Cancer Center Network. Ethics Approval: This study was approved by the Wake Forest University School of Medicine Institutional Review Board; IRB00126906. Clinical trial information: NCT06866964 .