Phase I/IB trial of sitravatinib (Sitra) + nivolumab (Nivo) + ipilimumab (Ipi) in patients (pts) with advanced clear cell renal cell carcinoma (accRCC) or other solid malignancies.
Authors: Msaouel Pavlos , Gao Jianjun , Yuan Ying , Siefker-Radtke Arlene O. , Jonasch Eric , Goswami Sangeeta , Zurita Amado J. , Campbell Matthew T , Shah Amishi Yogesh , Corn Paul G. , Ramos Claudia , Yan Xiaohong , Chin Curtis , Der-Torossian Hirak , Tannir Nizar M. 
Published: March 2021

TPS365 Background: Sitra is a spectrum-selective receptor tyrosine kinase inhibitor (TKI) that targets TAM receptors (TYRO3, AXL, MERTK), VEGFR2, c-Kit, and c-MET. Sitra has shown antitumor activity in accRCC, and reduces type 2 tumor-associated macrophages, regulatory T-cells and myeloid-derived suppressor cells and enhances T cell–mediated antitumor immune responses. The combination of sitra with anti-PD1 immune checkpoint inhibitors (ICIs), such as nivo, has an acceptable safety profile and demonstrates efficacy across multiple tumor types, including accRCC (Msaouel et al. J Clin Oncol, 2020, abstr 612). Ipi enhances the efficacy of nivo through distinct but complementary pathways to those targeted by sitra. We hypothesize that the triple combination of sitra + nivo + ipi will lead to more potent antitumor responses. This study is designed to determine the optimal dose of sitra when combined with nivo + ipi, and assess the safety as well as the preliminary efficacy of this combination in accRCC, and potentially other cancers, that have shown favorable responses to nivo + ipi. Methods: This phase I/Ib study (NCT04518046) is evaluating sitra + nivo + ipi in frontline advanced or metastatic ccRCC or other solid malignancies. The primary endpoint of the trial is safety and tolerability of this regimen. Secondary endpoints include: objective response rate (RECIST 1.1), duration of response, progression-free survival, overall survival, and pharmacokinetic measurements. The phase I dose escalation portion of the trial will enroll approximately 30 pts with intermediate- or poor-risk accRCC by International Metastatic RCC Database Consortium (IMDC) criteria, who will receive escalating doses of sitra (starting dose 35 mg orally QD) following the Time-to-Event Bayesian Optimal Interval (TITE-BOIN) design (Yuan et al. Clin Cancer Res, 2018), combined with nivo 3 mg/kg and ipi 1 mg/kg (NIVO3/IPI1) every 3 weeks (wks) for up to 4 doses, followed by maintenance nivo (240 mg every 2 wks or 480 mg every 4 wks). The phase Ib dose expansion cohorts will be initiated following identification of the recommended dose of sitra in combination with NIVO3/IPI1 and will enroll up to 31 pts for each of 2 cohorts: pts with intermediate-/poor-risk accRCC (Cohort A) and pts with favorable-risk accRCC (Cohort B). Pts will receive study treatment until disease progression, unacceptable adverse events, or pt withdrawal of consent. Future dose expansion cohorts may be added to include other solid tumors in which favorable activity has been previously demonstrated with nivo + ipi, such as metastatic urothelial carcinoma, melanoma, non–small-cell lung cancer, hepatocellular carcinoma, and colorectal cancer. The study is currently enrolling at 1 US site and additional sites may be added at dose expansion. At the time of the abstract submission, 3 pts have been enrolled. Clinical trial information: NCT04518046 .