Fruquintinib plus sintilimab in patients with either treatment-naive or previously first line treated metastatic clear-cell renal cell carcinoma (ccRCC): Results from a multicenter, single-arm phase 2 study

e16514 Background: Antiangiogenic therapy combined with immunotherapy significantly improved the progression-free survival (PFS) and preliminary survival benefit for advanced clear-cell renal cell carcinoma (ccRCC). However, no combined immune therapies are currently approved for ccRCC in China. Fruquintinib (F, a highly selective VEGFR inhibitor) combined with sintilimab (S, an anti-PD-1 monoclonal antibody) showed encouraging antitumor activity in multiple solid tumors. Here, we reported the results of F plus S in metastatic ccRCC cohort from an open-label, single-arm phase 2 study (NCT03903705). Methods: Patients (pts) with pathologically confirmed metastatic ccRCC who were treatment-naive or had failed previously first-line treatment were eligible. They received F (5 mg, 2 weeks on/1 week off, orally, QD) plus S (200 mg, IV, Q3W) in 21-day cycles until disease progression or unacceptable toxicity; treatment of S was allowed for up to 24 months. The primary endpoint was objective response rate (ORR) per RECIST v1.1. Results: As of cutoff (November 30, 2022), a total of 42 pts (22 treatment-naïve pts, and 20 previously first-line treated pts) were enrolled and received the combination treatment. Median (range) age was 59.0 (34.2-72.4) years; 34 (81.0%) pts were male. Among previously treated pts, 19 (19/20, 95.0%) pts had received VEGFR therapy as prior first-line treatment, including sunitinib (3/20, 15.0%), pazopanib (7/20, 35.0%), axitinib (2/20, 10.0%) and others (7/20, 35.0%). International Metastatic RCC Database Consortium (IMDC) risk included: favorable in 15 (35.7%) pts, intermediate in 22 (52.4%) pts, and poor in 5 (11.9%) pts. The median follow-up duration was 14.8 months (m) and 23.3 m for treatment-naive and previously treated pts, respectively. All pts had at least 1 post-baseline tumor assessment. Confirmed ORR was 68.2% and 60.0%, median duration of response was not reached (NR) and 13.9 m, and disease control rate was 95.5% and 85.0% for treatment-naive and previously treated pts, respectively. Median PFS (mPFS) was NR and 12m-PFS rate was 64.8% in treatment-naive pts; mPFS was 15.9 m in previously treated pts. The median treatment duration of F and S was both 14.7 m. All pts experienced at least 1 treatment-emergent adverse event (TEAE). Common (≥5%) grade ≥3 TEAEs were hypertension (21.4%), hypertriglyceridaemia (9.5%), amylase increased (7.1%), cerebral infarction (7.1%) and proteinuria (7.1%). No new safety signals were observed. Conclusions: F plus S demonstrated a favorable efficacy with manageable toxicity for treatment-naive and previously first-line treated metastatic ccRCC. A phase 2/3 study is being conducted to confirm this combination efficacy in the second-line treatment of ccRCC (NCT05522231). Clinical trial information: NCT03903705 .