A fixed-duration, measurable residual disease-guided approach in CLL: follow-up data from the phase 2 ICLL-07 FILO trial.

Trials assessing first-line, fixed-duration approaches in chronic lymphocytic leukemia (CLL) are yielding promising activity, but few long-term data are available. We report follow-up data from a phase 2 trial (ICLL07 FILO) in previously untreated, medically fit patients (N = 135). Patients underwent obinutuzumab-ibrutinib induction for 9 months; then, following evaluation (N = 130 evaluable), those in complete remission and with bone marrow measurable residual disease (BM MRD) <0.01% (n = 10) received ibrutinib for 6 additional months; those in partial remission and/or with BM MRD ≥0.01%, the majority (n = 120), also received 4 cycles of immunochemotherapy (fludarabine/cyclophosphamide-obinutuzumab). Beyond end of treatment, responses were assessed every 3 month and peripheral blood MRD every 6 months. At median follow-up 36.7 months from treatment start, progression-free and overall survival rates (95% confidence interval) at 3 years were 95.7% (92.0% to 99.5%) and 98% (95.1% to 100%), respectively. Peripheral blood MRD <0.01% rates were 97%, 96%, 90%, 84%, and 89% at months 16, 22, 28, 34, and 40, respectively. No new treatment-related or serious adverse event occurred beyond end of treatment. Thus, in previously untreated, medically fit patients with CLL, a fixed-duration (15 months), MRD-guided approach achieved high survival rates, a persistent MRD benefit beyond the end of treatment, and low long-term toxicity. This trial was registered at www.clinicaltrials.gov as #NCT02666898.

Obinutuzumab and ibrutinib induction therapy followed by a minimal residual disease-driven strategy in patients with chronic lymphocytic leukaemia (ICLL07 FILO): a single-arm, multicentre, phase 2 trial.

BACKGROUND: In patients with chronic lymphocytic leukaemia, achievement of a complete response with minimal residual disease of less than 0·01% (ie, <1 chronic lymphocytic leukaemia cell per 10 000 leukocytes) in bone marrow has been associated with improved progression-free survival. We aimed to explore the activity of induction therapy for 9 months with obinutuzumab and ibrutinib, followed up with a minimal residual disease-driven therapeutic strategy for 6 additional months, in previously untreated patients. METHODS: We did a single-arm, phase 2 trial in 27 university hospitals, general hospitals, and specialist cancer centres in France. Eligible patients were at least 18 years old and previously untreated, and had immunophenotypically confirmed B-cell chronic lymphocytic leukaemia; an Eastern Cooperative Oncology Group (ECOG) performance status score of less than 2; a Binet stage C according to IWCLL 2008 criteria or Binet stage A and B with active disease; no 17p deletion or absence of p53 mutation; and were considered medically fit. In the first part of the study (induction phase), all participants received eight intravenous infusions of obinutuzumab 1000 mg over six 4-weekly cycles and oral ibrutinib 420 mg once per day for 9 months. In part 2, after assessment on day 1 of month 9, patients with a complete response and bone marrow minimal residual disease of less than 0·01% received only oral ibrutinib 420 mg once per day for 6 additional months. Patients with a partial response, or with a complete response and bone marrow minimal residual disease of 0·01% or more, received 6 months of four 4-weekly cycles of intravenous fludarabine, cyclophosphamide, and obinutuzumab 1000 mg, alongside continuing ibrutinib 420 mg once per day. The primary endpoint was the proportion of patients achieving a complete response with bone marrow minimal residual disease less than 0·01% on day 1 of month 16 assessed by intention to treat (ITT). This trial is registered with ClinicalTrials.gov (number NCT02666898) and is still open for follow-up. FINDINGS: Between Oct 27, 2015, and May 16, 2017, 135 patients were enrolled. After induction treatment (day 1 of month 9), 130 patients were evaluable, of which ten (8%) achieved a complete response with bone marrow minimal residual disease of less than 0·01% and were assigned to ibrutinib, and 120 (92%) were assigned to ibrutinib plus fludarabine, cyclophosphamide, and obinutuzumab. After minimal residual disease-guided treatment (day 1 of month 16), 84 (62%, 90% CI 55-69) of 135 patients (ITT population) achieved a complete response with bone marrow minimal residual disease of less than 0·01%. The most common haematological adverse event was thrombocytopenia (in 45 [34%] of 133 patients at grade 1-2 in months 1-9 and in 43 [33%] of 130 patients at grade 1-2 in months 9-15). The most common non-haematological adverse events were infusion-related reactions (in 83 [62%] patients at grade 1-2 in months 1-9) and gastrointestinal disorders (in 62 [48%] patients at grades 1 and 2 in months 9-15). 49 serious adverse events occurred, most frequently infections (ten), cardiac events (eight), and haematological events (eight). No treatment-related deaths occurred. INTERPRETATION: Obinutuzumab and ibrutinib induction therapy followed by a minimal residual disease driven strategy is safe and active in patients with previously untreated chronic lymphocytic leukaemia. With longer follow-up, including assessing the evolution of minimal residual disease, if response is maintained, this strategy could be an option in the first-line setting in patients with chronic lymphocytic leukaemia, although randomised evidence is needed. FUNDING: Roche, Janssen.