Early On-Treatment Assessment of T Cells, Cytokines, and Tumor DNA with Adaptively Dosed Nivolumab + Ipilimumab: Final Results from the Phase 2 ADAPT-IT Study.

PURPOSE: The Adaptively Dosed ImmunoTherapy Trial (ADAPT-IT;NCT03122522) investigated adaptive ipilimumab discontinuation in melanoma based on early radiographic assessment. Initial findings indicated similar effectiveness compared with conventional nivolumab-ipilimumab (nivo-ipi). Exploratory biomarker analyses and final clinical results are now reported. PATIENTS AND METHODS: Patients with unresectable melanoma received two doses of nivo-ipi. Radiographic assessment at Week 6 informed continuation of ipilimumab before nivolumab maintenance. The primary endpoint was overall response rate at Week 12. Plasma was assayed for circulating tumor DNA and 10 cytokines using a multiplex immunoassay. Flow cytometry of peripheral blood mononuclear cells was performed with an 11-color panel. RESULTS: Among the treated patients, expansion of proliferating T-cell populations was observed in responders and nonresponders. Baseline IL6 levels were low in patients achieving an objective radiographic response (median 1.30 vs. 2.86 pg/mL; P = 0.025). High baseline IL6 levels were associated with short progression-free survival [PFS; HR = 1.24, 95% confidence interval (CI), 1.01-1.52; P = 0.041]. At Week 6, patients with response had lower average tumor variant allele fractions than nonresponders (median 0.000 vs. 0.019; P = 0.014). Greater increases in average variant allele fractions from baseline to Week 6 correlated with short PFS (HR = 1.11, 95% CI, 1.01-1.21; P = 0.023). Week 12 overall response rate was 47% (95% CI, 35%-59%) with a median follow-up of 34 months among survivors. Median PFS was 21 months (95% CI, 10-not reached); 76% of responses (95% CI, 64%-91%) persisted at 36 months. CONCLUSIONS: Adaptively dosed nivo-ipi responses are durable and resemble historical data for conventional nivo-ipi. Baseline IL6 and circulating tumor DNA changes during treatment warrant further study as biomarkers of nivo-ipi response.

Adaptive Dosing of Nivolumab + Ipilimumab Immunotherapy Based Upon Early, Interim Radiographic Assessment in Advanced Melanoma (The ADAPT-IT Study).

PURPOSE: Nivolumab + ipilimumab (nivo + ipi) is highly efficacious but has high toxicity. Standard treatment in advanced melanoma is four doses of nivo + ipi followed by nivo alone. Whether four doses of nivo + ipi are needed is unclear. METHODS: The Adaptively Dosed ImmunoTherapy Trial (ADAPT-IT) study (NCT03122522) is a multicenter, single-arm phase II clinical trial. Patients received two doses of nivo (1 mg/kg) + ipi (3 mg/kg) followed by a computed tomography scan at week 6. Patients without new lesions or index lesion tumor growth of > 4% had protocol-defined early favorable antitumor effect (FATE) and ceased nivo + ipi, transitioning to nivo monotherapy. Patients without FATE at week 6 received the standard third and fourth doses of nivo + ipi followed by nivo monotherapy. The primary end point was response rate by RECIST 1.1 at week 12. Secondary end points included additional efficacy assessments and safety. RESULTS: Sixty patients were enrolled; 41 patients (68%) had FATE at week 6 and met criteria for stopping nivo + ipi. Best overall response rates by RECIST at week 12 or any time afterward were 48% (95% CI, 35 to 62) and 58% (95% CI, 45 to 71), respectively. With a median follow-up of 25 months, the estimated 18-month progression-free survival and overall survival are 52% and 80%, respectively. Fifty seven percent of patients had grade 3-5 treatment-related toxicity. CONCLUSION: The efficacy and toxicity of standard four dose nivo + ipi induction therapy in melanoma is likely driven by the first two doses. An interim computed tomography scan after two doses guided cessation of combination dosing and identified almost all responders. Longer follow-up and further study are needed to fully understand the implications of a shortened induction course of nivo + ipi.