High prognostic value of measurable residual disease detection by flow cytometry in chronic lymphocytic leukemia patients treated with front-line fludarabine, cyclophosphamide, and rituximab, followed by three years of rituximab maintenance.

It has been postulated that monitoring measurable residual disease (MRD) could be used as a surrogate marker of progression-free survival (PFS) in chronic lymphocytic leukemia (CLL) patients after treatment with immunochemotherapy regimens. In this study, we analyzed the outcome of 84 patients at 3 years of follow-up after first-line treatment with fludarabine, cyclophosphamide and rituximab (FCR) induction followed by 36 months of rituximab maintenance thearpy. MRD was assessed by a quantitative four-color flow cytometry panel with a sensitivity level of 10-4 Eighty out of 84 evaluable patients (95.2%) achieved at least a partial response or better at the end of induction. After clinical evaluation, 74 patients went into rituximab maintenance and the primary endpoint was assessed in the final analysis at 3 years of follow-up. Bone marrow (BM) MRD analysis was performed after the last planned induction course and every 6 months in cases with detectable residual disease during the 36 months of maintenance therapy. Thirty-seven patients (44%) did not have detectable residual disease in the BM prior to maintenance therapy. Interestingly, 29 patients with detectable residual disease in the BM after induction no longer had detectable disease in the BM following maintenance therapy. After a median followup of 6.30 years, the median overall survival (OS) and PFS had not been reached in patients with either undetectable or detectable residual disease in the BM, who had achieved a complete response at the time of starting maintenance therapy. Interestingly, univariate analysis showed that after rituximab maintenance OS was not affected by IGHV status (mutated vs unmutated OS: 85.7% alive at 7.2 years vs 79.6% alive at 7.3 years, respectively). As per protocol, 15 patients (17.8%), who achieved a complete response and undetectable peripheral blood and BM residual disease after four courses of induction, were allowed to stop fludarabine and cyclophosphamide and complete two additional courses of rituximab and continue with maintenance therapy for 18 cycles. Surprisingly, the outcome in this population was similar to that observed in patients who received the full six cycles of the induction regimen. These data show that, compared to historic controls, patients treated with FCR followed by rituximab maintenance have high-quality responses with fewer relapses and improved OS. The tolerability of this regime is favorable. Furthermore, attaining an early undetectable residual disease status could shorten the duration of chemoimmunotherapy, reducing toxicities and preventing long-term side effects. The analysis of BM MRD after fludarabine-based induction could be a powerful predictor of post-maintenance outcomes in patients with CLL undergoing rituximab maintenance and could be a valuable tool to identify patients at high risk of relapse, influencing further treatment strategies. This trial is registered with EudraCT n. 2007-002733-36 and ClinicalTrials.gov Identifier: NCT00545714.

García-Marco JA ，Jiménez JL ，Recasens V ，Zarzoso MF ，González-Barca E ，De Marcos NS ，Ramírez MJ ，Parraga FJP ，Yañez L ，De La Serna Torroba J ，Malo MDG ，Ariznavarreta GD ，Persona EP ，Guinaldo MAR ，De Paz Arias R ，Llanos EB ，Jarque I ，Valle MDCF ，Tatay AC ，De Oteyza JP ，Martin EMD ，Fernández IP ，Martinez RM ，Costa MAA ，Champ D ，Suarez JG ，Díaz MG ，Ferrer S ，Carbonell F ，García-Vela JA ，GELLC Study Group ... -  《-》

Ibrutinib plus fludarabine, cyclophosphamide, and rituximab as initial treatment for younger patients with chronic lymphocytic leukaemia: a single-arm, multicentre, phase 2 trial.

Fludarabine, cyclophosphamide, and rituximab (FCR) can improve disease-free survival for younger (age ≤65 years) fit patients with chronic lymphocytic leukaemia with mutated IGHV. However, patients with unmutated IGHV rarely have durable responses. Ibrutinib is active for patients with chronic lymphocytic leukaemia irrespective of IGHV mutation status but requires continuous treatment. We postulated that time-limited ibrutinib plus FCR would induce durable responses in younger fit patients with chronic lymphocytic leukaemia. We did a multicentre, open-label, non-randomised, single-arm phase 2 trial at seven sites in the USA. We enrolled patients aged 65 years or younger with previously untreated chronic lymphocytic leukaemia. Our initial cohort (original cohort) was not restricted by prognostic marker status and included patients who had del(17p) or TP53 aberrations. After a protocol amendment (on March 21, 2017), we enrolled an additional cohort (expansion cohort) that included patients without del(17p). Ibrutinib was given orally (420 mg/day) for 7 days, then up to six 28-day cycles were administered intravenously of fludarabine (25 mg/m2, days 1-3), cyclophosphamide (250 mg/m2, days 1-3), and rituximab (375 mg/m2 day 1 of cycle 1; 500 mg/m2 day 1 of cycles 2-6) with continuous oral ibrutinib (420 mg/day). Responders continued on ibrutinib maintenance for up to 2 years, and patients with undetectable minimal residual disease in bone marrow after 2 years were able to discontinue treatment. The primary endpoint was the proportion of patients who achieved a complete response with undetectable minimal residual disease in bone marrow 2 months after the last cycle of ibrutinib plus FCR. Analyses were done per-protocol in all patients who received at least one dose of study treatment. This trial is registered with ClinicalTrials.gov (NCT02251548) and is ongoing. Between Oct 23, 2014, and April 23, 2018, 85 patients with chronic lymphocytic leukaemia were enrolled. del(17p) was detected in four (5%) of 83 patients and TP53 mutations were noted in three (4%) of 81 patients; two patients had both del(17p) and TP53 mutations. Median patients' age was 55 years (IQR 50-58). At data cutoff, median follow-up was 16·5 months (IQR 10·6-34·1). A complete response and undetectable minimal residual disease in bone marrow 2 months after the last cycle of ibrutinib plus FCR was achieved by 28 (33%, 95% CI 0·23-0·44) of 85 patients (p=0·0035 compared with a 20% historical value with FCR alone). A best response of undetectable minimal residual disease in bone marrow was achieved by 71 (84%) of 85 patients during the study. One patient had disease progression and one patient died (sudden cardiac death after 17 months of ibrutinib maintenance, assessed as possibly related to ibrutinib). The most common all-grade toxic effects were haematological, including thrombocytopenia in 63 (74%) patients, neutropenia in 53 (62%), and anaemia in 41 (49%). Grade 3 or 4 non-haematological serious adverse events included grade 3 atrial fibrillation in three (4%) patients and grade 3 Pneumocystis jirovecii pneumonia in two (2%). The proportion of patients who achieved undetectable minimal residual disease in bone marrow with ibrutinib plus FCR is, to our knowledge, the highest ever published in patients with chronic lymphocytic leukaemia unrestricted by prognostic marker status. Ibrutinib plus FCR is promising as a time-limited combination regimen for frontline chronic lymphocytic leukaemia treatment in younger fit patients. Pharmacyclics and the Leukemia & Lymphoma Society.

Davids MS ，Brander DM ，Kim HT ，Tyekucheva S ，Bsat J ，Savell A ，Hellman JM ，Bazemore J ，Francoeur K ，Alencar A ，Shune L ，Omaira M ，Jacobson CA ，Armand P ，Ng S ，Crombie J ，LaCasce AS ，Arnason J ，Hochberg EP ，Takvorian RW ，Abramson JS ，Fisher DC ，Brown JR ，Blood Cancer Research Partnership of the Leukemia & Lymphoma Society ... -  《Lancet Haematology》

Fludarabine, cyclophosphamide, and rituximab treatment achieves long-term disease-free survival in IGHV-mutated chronic lymphocytic leukemia.

Accurate identification of patients likely to achieve long-progression-free survival (PFS) after chemoimmunotherapy is essential given the availability of less toxic alternatives, such as ibrutinib. Fludarabine, cyclophosphamide, and rituximab (FCR) achieved a high response rate, but continued relapses were seen in initial reports. We reviewed the original 300 patient phase 2 FCR study to identify long-term disease-free survivors. Minimal residual disease (MRD) was assessed posttreatment by a polymerase chain reaction-based ligase chain reaction assay (sensitivity 0.01%). At the median follow-up of 12.8 years, PFS was 30.9% (median PFS, 6.4 years). The 12.8-year PFS was 53.9% for patients with mutated immunoglobulin heavy chain variable (IGHV) gene (IGHV-M) and 8.7% for patients with unmutated IGHV (IGHV-UM). 50.7% of patients with IGHV-M achieved MRD-negativity posttreatment; of these, PFS was 79.8% at 12.8 years. A plateau was seen on the PFS curve in patients with IGHV-M, with no relapses beyond 10.4 years in 42 patients (total follow-up 105.4 patient-years). On multivariable analysis, IGHV-UM (hazard ratio, 3.37 [2.18-5.21]; P < .001) and del(17p) by conventional karyotyping (hazard ratio, 7.96 [1.02-61.92]; P = .048) were significantly associated with inferior PFS. Fifteen patients with IGHV-M had 4-color MRD flow cytometry (sensitivity 0.01%) performed in peripheral blood, at a median of 12.8 years posttreatment (range, 9.5-14.7). All were MRD-negative. The high rate of very long-term PFS in patients with IGHV-M after FCR argues for the continued use of chemoimmunotherapy in this patient subgroup outside clinical trials; alternative strategies may be preferred in patients with IGHV-UM, to limit long-term toxicity.

Thompson PA ，Tam CS ，O'Brien SM ，Wierda WG ，Stingo F ，Plunkett W ，Smith SC ，Kantarjian HM ，Freireich EJ ，Keating MJ ... -  《-》

Minimal residual disease undetectable by next-generation sequencing predicts improved outcome in CLL after chemoimmunotherapy.

Patients with chronic lymphocytic leukemia (CLL) who achieve blood or bone marrow (BM) undetectable minimal residual disease (U-MRD) status after first-line fludarabine, cyclophosphamide, and rituximab (FCR) have prolonged progression-free survival (PFS), when assessed by an assay with sensitivity 10-4 (MRD4). Despite reaching U-MRD4, many patients, especially those with unmutated IGHV, subsequently relapse, suggesting residual disease <10-4 threshold and the need for more sensitive MRD evaluation. MRD evaluation by next-generation sequencing (NGS) has a sensitivity of 10-6 (MRD6). To better assess the depth of remission following first-line FCR treatment, we used NGS (Adaptive Biotechnologies Corporation) to assess MRD in 62 patients, all of whom had BM U-MRD by multicolor flow cytometry (sensitivity 10-4) at end-of-FCR treatment. Samples from these patients included 57 BM samples, 29 peripheral blood mononuclear cell (PBMC) samples, and 32 plasma samples. Only 27.4% of the 62 patients had U-MRD by NGS. Rate of U-MRD by NGS was lowest in BM (25%), compared with PBMC (55%) or plasma (75%). No patient with U-MRD by NGS in BM or PBMC was MRD+ in plasma. Patients with mutated IGHV were more likely to have U-MRD by NGS at the end of treatment (EOT; 41% vs 13%, P = .02) than those with unmutated IGHV. Median follow-up was 81.6 months. Patients with U-MRD at EOT had superior PFS vs MRD+ patients, regardless of sample type assessed (BM, P = .02, median not reached [NR] vs 67 months; PBMC, P = .02, median NR vs 74 months). More sensitive MRD6 testing increases prognostic discrimination over MRD4 testing.

Thompson PA ，Srivastava J ，Peterson C ，Strati P ，Jorgensen JL ，Hether T ，Keating MJ ，O'Brien SM ，Ferrajoli A ，Burger JA ，Estrov Z ，Jain N ，Wierda WG ... -  《-》

Reduced-dose fludarabine, cyclophosphamide, and rituximab (FCR-Lite) plus lenalidomide, followed by lenalidomide consolidation/maintenance, in previously untreated chronic lymphocytic leukemia.

Fludarabine, cyclophosphamide, and rituximab (FCR) remains the standard of care for fit chronic lymphocytic leukemia (CLL) patients requiring first therapy. However, side effects can be significant, and patients with poor risk features have inferior outcomes. The purpose of this study was to evaluate reduced-dose FCR (FCR-Lite) plus lenalidomide (FCR(2) ) followed by lenalidomide maintenance as a strategy to shorten immunochemotherapy in untreated CLL. Patients received four to six cycles of FCR(2) . Patients who were minimal residual disease (MRD) negative in peripheral blood (PB) and bone marrow (BM) initiated 12 months of lenalidomide maintenance after either four or six cycles (based on MRD status). The primary study endpoint was the complete response (CR) rate after four cycles of FCR(2) . Twenty patients were evaluable. After four cycles of FCR(2) , response rates were: CR, 45.0%; CR with incomplete blood count recovery (CRi), 5.0%; partial response (PR), 45.0%; and stable disease (SD), 5.0%. BM and PB samples from 27.8% and 52.9% of patients, respectively, were MRD negative. After six cycles, response rates were: CR, 58.3%; CRi, 16.7%; and PR, 25.0%. BM and PB samples from 50.0% and 72.7% of patients, respectively, were MRD negative. Overall, 75% of evaluable patients achieved a CR or CRi following FCR(2) . After 17.4 months of median follow-up, one progression and one death occurred. Our findings suggest that FCR(2) combines encouraging clinical activity with acceptable toxicity in previously untreated CLL. Lenalidomide can be safely added to FCR and may reduce chemotherapy exposure without compromising outcomes.

Mato AR ，Foon KA ，Feldman T ，Schuster SJ ，Svoboda J ，Chow KF ，Valentinetti M ，Mrkulic M ，Azzollini K ，Gadaleta G ，Bhattacharyya PK ，Zenreich J ，Pascual LN ，Yannotti K ，Kdiry S ，Howlett C ，Strelec L ，Porter D ，Bejot C ，Goy A ... -  《-》