A randomized, open-label, phase 3 trial of pembrolizumab plus epacadostat versus sunitinib or pazopanib as first-line treatment for metastatic renal cell carcinoma (KEYNOTE-679/ECHO-302).

Immunotherapy-based combinations have emerged as standard therapies for patients with metastatic renal cell carcinoma (mRCC). Pembrolizumab, a PD-1 inhibitor, combined with epacadostat, an indoleamine 2,3-deoxygenase 1 selective inhibitor, demonstrated promising antitumor activity in a phase 1 study in advanced solid tumors, including mRCC. KEYNOTE-679/ECHO-302 was a randomized, open-label, parallel-group, multicenter, phase 3 study (NCT03260894) that compared pembrolizumab plus epacadostat with sunitinib or pazopanib as first-line treatment for mRCC. Eligible patients had histologically confirmed locally advanced or metastatic clear cell RCC and had not received systemic therapy. Patients were randomly assigned 1:1 to pembrolizumab 200 mg IV every 3 weeks plus epacadostat 100 mg orally twice daily versus sunitinib 50 mg orally once daily (4 weeks on treatment followed by 2 weeks off treatment) or pazopanib 800 mg orally once daily. Original dual primary end points were progression-free survival and overall survival. Enrollment was stopped when a phase 3 study in melanoma of pembrolizumab plus epacadostat compared with pembrolizumab monotherapy did not meet its primary end point. This protocol was amended, and primary end point was changed to investigator-assessed objective response rate (ORR) per RECIST 1.1. One-hundred-twenty-nine patients were randomly assigned to receive pembrolizumab plus epacadostat (n = 64) or sunitinib/pazopanib (n = 65). Median (range) follow-up, defined as time from randomization to data cutoff, was 10.3 months (2.2-14.3) and 10.3 months (2.7-13.8) in the pembrolizumab plus epacadostat and sunitinib/pazopanib arms, respectively. ORRs were similar between pembrolizumab plus epacadostat (31.3% [95% CI 20.2-44.1] and sunitinib/pazopanib (29.2% [18.6-41.8]). Grade 3-5 treatment-related adverse events occurred in 34.4% and 42.9% of patients in the pembrolizumab plus epacadostat and sunitinib/pazopanib arms, respectively. One patient in the sunitinib/pazopanib arm died of septic shock (not treatment-related). Circulating kynurenine levels decreased in the pembrolizumab plus epacadostat arm, but not to levels observed in healthy subjects. ORRs were similar between pembrolizumab plus epacadostat and sunitinib/pazopanib as first-line treatment in patients with mRCC. Safety and tolerability appeared similar between treatment arms; no new safety concerns were identified. Antitumor responses observed in patients with RCC receiving pembrolizumab plus epacadostat may be driven primarily by pembrolizumab. ClinicalTrials.gov; NCT03260894 .

Lara PN Jr ，Villanueva L ，Ibanez C ，Erman M ，Lee JL ，Heinrich D ，Lipatov ON ，Gedye C ，Gokmen E ，Acevedo A ，Semenov A ，Park SH ，Gafanov RA ，Kose F ，Jones M ，Du X ，Munteanu M ，Perini R ，Choueiri TK ，Motzer RJ ... -  《BMC CANCER》

Pembrolizumab plus either epacadostat or placebo for cisplatin-ineligible urothelial carcinoma: results from the ECHO-307/KEYNOTE-672 study.

Indoleamine 2,3- dioxygenase 1 (IDO1) is an immunosuppressive enzyme that has been correlated with shorter disease-specific survival in patients with urothelial carcinoma (UC). IDO1 may counteract the antitumor effects of immune checkpoint inhibitors. Epacadostat is a potent and highly selective inhibitor of IDO1. In the phase I/II ECHO-202/KEYNOTE-037 study, epacadostat plus pembrolizumab resulted in a preliminary objective response rate (ORR) of 35% in a cohort of patients with advanced UC. ECHO-307/KEYNOTE-672 was a double-blinded, randomized, phase III study. Eligible adults had confirmed locally advanced/unresectable or metastatic UC of the urinary tract and were ineligible to receive cisplatin-based chemotherapy. Participants were randomly assigned (1:1) to receive epacadostat (100 mg twice daily) plus pembrolizumab (200 mg every 3 weeks) or placebo plus pembrolizumab for up to 35 pembrolizumab infusions. The primary endpoint was investigator-assessed ORR per Response Evaluation Criteria in Solid Tumors (version 1.1). A total of 93 patients were randomized (epacadostat plus pembrolizumab, n = 44; placebo plus pembrolizumab, n = 49). Enrollment was stopped early due to emerging data from the phase III ECHO-301/KEYNOTE-252 study. The median duration of follow-up was 64 days in both arms. Based on all available data at cutoff, ORR (unconfirmed) was 31.8% (95% CI, 22.46-55.24%) for epacadostat plus pembrolizumab and 24.5% (95% CI, 15.33-43.67%) for placebo plus pembrolizumab. Circulating kynurenine levels numerically increased from C1D1 to C2D1 in the placebo-plus-pembrolizumab arm and decreased in the epacadostat-plus-pembrolizumab arm. Epacadostat-plus-pembrolizumab combination treatment was well tolerated with a safety profile similar to the placebo arm. Treatment discontinuations due to treatment-related adverse events were more frequent with epacadostat (11.6% vs. 4.1%). Treatment with epacadostat plus pembrolizumab resulted in a similar ORR and safety profile as placebo plus pembrolizumab in cisplatin-ineligible patients with previously untreated locally advanced/unresectable or metastatic UC. At a dose of 100 mg twice daily, epacadostat did not appear to completely normalize circulating kynurenine levels when administered with pembrolizumab. Larger studies with longer follow-up and possibly testing higher doses of epacadostat, potentially in different therapy settings, may be warranted. ClinicalTrials.gov identifier: NCT03361865, retrospectively registered December 5, 2017.

Necchi A ，Van der Heijden MS ，Trukhin D ，Peer A ，Gurney H ，Alekseev BY ，Parnis FX ，Leibowitz R ，De Santis M ，Grivas P ，Clark J ，Munteanu M ，Kataria R ，Jia C ，Balar AV ，de Wit R ... -  《BMC CANCER》

Epacadostat plus pembrolizumab versus placebo plus pembrolizumab for advanced urothelial carcinoma: results from the randomized phase III ECHO-303/KEYNOTE-698 study.

Cicin I ，Plimack ER ，Gurney H ，Leibowitz R ，Alekseev BY ，Parnis FX ，Peer A ，Necchi A ，Bellmunt J ，Nishiyama H ，Clark J ，Munteanu M ，Kataria R ，Jia C ，Powles T ，Sternberg CN ... -  《BMC CANCER》

Pembrolizumab plus epacadostat in patients with recurrent/metastatic head and neck squamous cell carcinoma (KEYNOTE-669/ECHO-304): a phase 3, randomized, open-label study.

Advanced head and neck squamous cell carcinoma (HNSCC) has a poor prognosis, and new treatment options are needed. Combining immunotherapies with differing mechanisms of action may enhance clinical benefits compared with single-agent immunotherapy. Epacadostat, an indoleamine 2,3 dioxygenase 1 inhibitor, plus pembrolizumab, a PD-1 inhibitor, showed promising activity in advanced HNSCC in the phase 1/2 KEYNOTE-037/ECHO-202 trial. KEYNOTE-669/ECHO-304 is a randomized, open-label, phase 3 study evaluating the efficacy and safety of pembrolizumab plus epacadostat, pembrolizumab monotherapy, and the EXTREME regimen (cetuximab with a platinum [carboplatin or cisplatin] and 5-fluorouracil) in recurrent/metastatic (R/M) HNSCC. Participants had no prior systemic therapy for R/M HNSCC and were randomly assigned (2:1:2) to pembrolizumab 200 mg intravenously every 3 weeks plus epacadostat 100 mg orally twice daily, pembrolizumab monotherapy, or EXTREME. The primary endpoint was objective response rate (ORR; investigator assessment). Secondary endpoints were safety and tolerability. Change in serum kynurenine was an exploratory endpoint. Study enrollment was discontinued early as a strategic decision on May 2, 2018, and response assessment was discontinued after first on-study imaging assessment at week 9. Data cut-off was January 17, 2019. Between December 1, 2017, and May 2, 2018, 89 patients were randomly allocated to pembrolizumab plus epacadostat (n = 35), pembrolizumab monotherapy (n = 19), or EXTREME (n = 35). ORR (95% CI) was 31% (17%-49%) for pembrolizumab plus epacadostat, 21% (6%-46%) for pembrolizumab monotherapy, and 34% (19%-52%) for EXTREME. Treatment-related adverse events (TRAEs) occurred in 82% (n = 28) of patients receiving pembrolizumab plus epacadostat, 63% (n = 12) receiving pembrolizumab monotherapy, and 100% (n = 34) receiving EXTREME. Grade 3-4 TRAEs occurred in 24% (n = 8) of patients receiving pembrolizumab plus epacadostat, 16% (n = 3) receiving pembrolizumab monotherapy, and 82% (n = 28) receiving EXTREME. No deaths occurred due to AEs. Pembrolizumab plus epacadostat treatment reduced kynurenine levels but not to that of healthy subjects. Pembrolizumab plus epacadostat and pembrolizumab monotherapy provided a similar response rate to EXTREME and demonstrated a manageable safety profile in patients with R/M HNSCC. NCT03358472. Date of trial registration: November 30, 2017.

Cho BC ，Braña I ，Cirauqui B ，Aksoy S ，Couture F ，Hong RL ，Miller WH Jr ，Chaves-Conde M ，Teixeira M ，Leopold L ，Munteanu M ，Ge JY ，Swaby RF ，Hughes BGM ... -  《BMC CANCER》

Pembrolizumab with platinum-based chemotherapy with or without epacadostat as first-line treatment for metastatic non-small cell lung cancer: a randomized, partially double-blind, placebo-controlled phase II study.

The combination of the checkpoint inhibitor (CPI) pembrolizumab and platinum-based chemotherapy is effective frontline therapy for advanced non-small cell lung cancer (NSCLC) lacking targetable mutations. Indoleamine 2,3- dioxygenase 1 (IDO1), an enzyme involved in kynurenine production, inhibits immune responses. Inhibition of IDO1 may restore antitumor immunity and augment CPI activity. This trial evaluated addition of epacadostat, a potent and highly selective IDO1 inhibitor, to pembrolizumab and chemotherapy for metastatic NSCLC. ECHO-306/KEYNOTE-715 was a partial double-blind, randomized phase II study of adults with treatment-naïve stage IV NSCLC not indicated for EGFR-, ALK-, or ROS1-directed therapy. Patients were randomized to one of three treatment arms: epacadostat-pembrolizumab-chemotherapy (E + P + C; blinded), epacadostat-pembrolizumab (E + P; open-label) or placebo-pembrolizumab-chemotherapy (PBO + P + C; blinded). Stratification was by PD-L1 tumor proportion score (< 50% vs. ≥ 50%) and tumor histology (non-squamous vs. squamous). A protocol amendment closed enrollment in the open-label E + P group, excluding it from efficacy analyses. Intravenous pembrolizumab (200 mg) was administered every 21 days and epacadostat 100 mg or matching placebo (oral) twice daily (BID) for ≤ 35 3-week cycles. The primary objective was objective response rate (ORR) for E + P + C vs. PBO + P + C. 178 patients were randomized to E + P + C (n = 91) or PBO + P + C (n = 87); 55 were enrolled in the E + P group. The E + P + C group had a lower confirmed ORR (26.4%; 95% CI 17.7-36.7) than the PBO + P + C group (44.8%; 95% CI 34.1-55.9), with a difference of - 18.5% (95% CI - 32.0 - (- 4.3); one-sided P = 0.9948). The E + P + C group had a numerically higher percentage of confirmed responders with extended response ≥ 6 months (29.2% vs. 15.4%). Circulating kynurenine levels at C1D1 were similar to those at C2D1 in all treatment groups and were not reduced to normal levels with epacadostat 100 mg BID plus P + C. The safety profile of E + P + C was consistent with that for PBO + P + C. Addition of epacadostat 100 mg BID to pembrolizumab and platinum-based chemotherapy was generally well tolerated but did not improve ORR in patients with treatment-naïve metastatic NSCLC. Evaluating epacadostat doses that normalize circulating kynurenine in combination with CPIs may help determine the clinical potential of this combination. NCT03322566. Registered October 26, 2017.

Boyer M ，Hui R ，Urban D ，Clingan P ，Su WC ，Devaux C ，Gadgeel S ，Garassino M ，Leopold L ，Daniel J ，Munteanu MC ，Samkari A ，Luo Y ，Abreu DR ... -  《BMC CANCER》