Itacitinib for the Prevention of Immune Effector Cell Therapy–Associated Cytokine Release Syndrome: Results from the Phase 2 Incb 39110-211 Placebo-Controlled Randomized Cohort

Introduction: Cytokine release syndrome (CRS) and immune effector cell (IEC)–associated neurotoxicity syndrome (ICANS) are common adverse effects following IEC therapy. Janus kinase (JAK) pathways are important for the signaling of several cytokines involved in CRS pathogenesis. Itacitinib is a potent, selective JAK1 inhibitor with broad anti-inflammatory activity. We describe preliminary results from the randomized, placebo-controlled portion of the study evaluating itacitinib 200 mg twice daily (bid) for the prevention of CRS.

Methods: This randomized, placebo-controlled portion of the phase 2 Study INCB 39110-211 (NCT04071366) enrolled patients ≥18 years old planning to receive axicabtagene ciloleucel for relapsed/refractory large B-cell lymphoma (rrLBCL) and follicular lymphoma (rrFL). Participants received oral itacitinib 200 mg bid beginning 3 days before axicabtagene ciloleucel infusion and continued itacitinib through Day 26. Protocol did not allow tocilizumab for treatment of grade 1 CRS unless CRS did not improve after 72 hours of supportive treatment. Patients who received tocilizumab for grade 1 CRS were not censored. Primary endpoint was incidence of CRS grade ≥2 by Day 14 using American Society for Transplantation and Cellular Therapy grading system. Secondary endpoints included incidence of ICANS by Day 28, duration of CRS and ICANS, and itacitinib safety.

Results: 47 patients with rrLBCL were randomized to itacitinib (n=23; median age, 66 [range: 29–80] years; male, 65%) or placebo arms (n=24; median age, 64 [range: 31–79] years; male, 71%). Median (range) number of prior regimens was 2 (1–6) and 1.5 (1–4), respectively. No rrFL patients enrolled in the study. Two (8%) patients in the itacitinib arm received platelet transfusions after Day 28; no transfusions were received in the placebo group.

A total of 15 (65.2%) patients in the itacitinib arm developed CRS (grade 1, n=11 [47.8%]) compared with 20 (87.0%) patients in placebo arm (grade 1, n=7 [30.4%]; Figure). No hypotension or hypoxia was observed in patients with grade 1 CRS who received tocilizumab. Grade 2 CRS was experienced by 4 (17.4%) and 13 (56.5%) patients, respectively (P=0.003; 95% CI: 0.14–0.65). There was no grade 3 or 4 CRS in either arm. Median (range) time to any-grade CRS onset was 2 (0–8) days and 3 (0-9) days, respectively; median (range) duration of grade 2 CRS was 2 (1–8) and 2 (1–5) days. Overall, tocilizumab was used for CRS treatment in 4 (17.4%) patients in the itacitinib arm and in 15 (65.2%) patients in the placebo arm, including 2 and 6 patients, respectively, who received tocilizumab for grade 1 CRS. ICANS occurred in 3 (13%; 95% CI: 3–34) patients in the itacitinib arm and 8 (34.8%; 95% CI: 16–57) patients in the placebo arm (Figure). ICANS grade ≥2 was reported in 2 (8.6%; 95% CI: 1–28) and 5 (21.7%; 95% CI: 8–44) patients, respectively. No grade 4 ICANS occurred in either arm. Median (range) time to any-grade ICANS onset was 5 (4–9) days and 6.5 (2–11) days, respectively; median (range) duration was 2 (2–11) and 3.5 (2–13) days.

Persistent grade 3 or 4 thrombocytopenia at Day 28 in the itacitinib arm was reported in 8 (38.1%; [grade 4: n=4]) patients; in the placebo arm in 4 (18.2%; [grade 4: n=0]) patients. Persistent grade 3 or 4 neutropenia at Day 28 in the itacitinib arm was reported in 7 (33.3%; [grade 4: n=3]) patients; in the placebo arm in 3 (13.6%; [grade 4: n=0]) patients. Infections grade ≥3 occurred before Day 28 in 2 (8.7%) patients in the itacitinib arm (urinary tract infection [UTI], n=2) and in 3 (12.5%) patients in the placebo arm (sepsis, n=2; UTI, n=1). There were no fatal adverse events. With a minimum follow-up of 28 days, lymphoma best overall response to axicabtagene ciloleucel showed no difference between the 2 arms.

Conclusions: Results from the randomized, placebo-controlled portion of Study INCB 39110-211 have shown prophylaxis treatment with itacitinib 200 mg bid to be well tolerated and resulted in a lower rate and grade of CRS and ICANS after lymphoma treatment with axicabtagene ciloleucel. Incidence of grade 3/4 neutropenia and thrombocytopenia not resolved at Day 28 was higher with itacitinib vs placebo. Rates of severe infections were comparable in both arms. Longer follow-up data on lymphoma response will be available upon presentation. Biomarker analyses comparing the effect of itacitinib on CAR-T cells expansion and function are ongoing.