Phase IB study of sorafenib and evofosfamide in patients with advanced hepatocellular and renal cell carcinomas (NCCTG N1135, Alliance)

Background Sorafenib (Sor) remains a first-line option for hepatocellular carcinoma (HCC) or refractory renal cell carcinomas (RCC). PLC/PRF/5 HCC model showed upregulation of hypoxia with enhanced efficacy when Sor is combined with hypoxia-activated prodrug evofosfamide (Evo). Methods This phase IB 3 + 3 design investigated 3 Evo dose levels (240, 340, 480 mg/m² on days 8, 15, 22), combined with Sor 200 mg orally twice daily (po bid) on days 1–28 of a 28-day cycle. Primary objectives included determining maximum tolerated dose (MTD) and recommended phase II dose (RP2D) of Sor + Evo. Results Eighteen patients were enrolled (median age 62.5 years; 17 male /1 female; 12 HCC/6 RCC) across three dose levels (DL0: Sor 200 mg bid/Evo 240 mg/m² [n = 6], DL1:Sor 200 mg bid/Evo 480 mg/m² [n = 5], DL1a: Sor 200 mg bid/Evo 340 mg/m² [n = 7]). Two dose-limiting toxicities (DLTs) were reported with Evo 480 mg/m² (grade 3 mucositis, grade 4 hepatic failure). Grade 3 rash DLT was observed in one patient at Evo 240 mg/m². No DLTs were observed at Evo 340 mg/m². MTD and RP2D were established as Sor 200 mg/Evo 340 mg/m² and Sor 200/Evo 240 mg/m², respectively. The most common treatment-related adverse events included fatigue, hand-foot syndrome, hypertension, and nausea/vomiting. Two partial responses were observed, one each at DL0 and DL1a.; disease control rate was 55%. Conclusions RP2D was established as sorafenib 200 mg bid + Evo 240 mg/m². While preliminary anti-tumor activity was observed, future development must account for advances in immunotherapy in HCC/RCC.