Salvage Therapies in Patients with High-Risk Relapse After Fludarabine, Cyclophosphamide, Rituximab (FCR) for Chronic Lymphocytic Leukemia: The French CLL Intergroup Experience
Authors: Fornecker Luc-Matthieu , Aurran-Schleinitz Therese , Michallet Anne-Sophie , Cazin Bruno , Dupuis Jehan , Guieze Romain , Dilhuydy Marie-Sarah , Zini Jean-Marc , Tomowiak Cécile , Leprêtre Stéphane , Cymbalista Florence , Brion Annie , Feugier Pierre , Leblond Veronique , Ysebaert Loic 
Published: October 2019

Abstract
Abstract 1796

Introduction:
FCR chemoimmunotherapy is recommended as first line therapy for fit cll patients. Since the 2007 EBMT guidelines based on the previously published trials using FCR, the definition of high risk CLL has evolved, to include biologic parameters (TP53 disruption by deletion/mutation, high b2-microglobulin level, IgVH unmutated, complex karyotype), refractoriness (progression during fluda-based regimen or within 6mo of completion), and also remission duration (high risk if PFS after FCR <24mo, ultra-high risk if TTNT <24–36mo with TP53 del/mut). However, few data are available regarding the characteristiscs, response rate and outcome of CLL patients treated in second line after FCR first line.

Patients and methods:
In this multicentric retrospective study, we collected data from 117 patients who relapsed after FCR first line therapy and received second-line therapy (according to NCI2008 guidelines).

Results:

At the time of initial FCR therapy:
patients characteristics were as follows: Binet B/C 87.2%, unmutated IgVH 52.2%, del11q 25.6% (n=30/81 with FISH available), del17p 6.8% (n=8/87 with FISH available), bulk>5cm 22%, complex karyotype 21% (n=12/57 with karyotype available). FCR yielded 93% ORR, with 66% clinical CR, 27% PR, and 7% failed to respond. Median PFS and TTNT were 27mo and 32.5mo, respectively.

At the time of relapse:
patients characteristics were as follows: del11q 16.4% (n=19/65 with FISH available), del17p 19% (n=22/77), bulk>5cm 26%, complex karyotype 44% (n=24/54 with karyotype available). According to FCR remission duration, 11.1% of patients were considered as truly FCR-refractory, 47% had PFS<24mo, 34.2% had TTNT<24mo. TTNT<24mo after FCR was correlated to age>65y, del17p (20% vs 0%) and complex karyotype (38% vs11%), but not with gender, IgVH status, del11q, or bulk>5cm. Based on FCR-refractoriness, or TTNT<24mo and/or del17p, 53 patients were considered as ultra-high risk (45.3%).
Various regimen were used for second-line treatment after FCR: R-bendamustine (n=47, 40.2%), alemtuzumab-based therapy (single agent or with chemo/dexa, n=22, 18.8%), R-CHOP (n=15, 12.8%), FCR (n=14, 12%), and other miscellaneous regimens (as follows: R-alkylator (n=6, 5.1%), R-DHAP (n=4, 3.4%), R-methylprednisolone (n=3, 2.6%), or investigational drugs (n=6, 5.1%)). Thus, 74.3% of patients received a second course including rituximab-based chemotherapy. Overall response rate was 78.4%, with 13.8% clinical CR, 64.6% PR, and 21.6% failure/stable disease. 14 pts (12%) underwent stem cell transplantations, 8 had maintenance therapy ongoing (ofatumumab, alemtuzumab, or lenalidomide). With regards to factors defining high-risk relapse, distribution of salvage therapies was as follows:
As expected, a second course of FCR was seldom used in high-risk patients. Among ultra-high risk patients, 30.3% received R-benda, 11.3% Alem-based Rx, 32% R-CHOP and 18% the miscellaneous regimens described above.
After second-line therapy, median PFS was 12 months, median TTNT was 14mo, and median OS was 36mo (20 deaths). On univariate analysis, complex karyotype (p=0.04) but not del17p (p=0.1), PFS<24mo (p=0.028) and TTNT<24mo (p=0.04) correlated with OS. Regarding treatment, OS was significantly improved in R-bendamustine-treated patients, as compared to alem-based or CHOP regimen (p=0.01). Most importantly, patients who received an allogeneic transplant benefited from significantly prolonged OS (at 4y, 70% vs 40%, p=0.03). Of note, only one patient treated with R-benda received allotransplant.

Conclusions:
This study shows that there are no consensus for second line therapy after FCR. Second line trials after FCR therapy are warranted. Definition of high-risk subsets of patients at relapse after FCR is of upmost importance in the management of CLL, to compare second-line strategies. Our data suggest that R-bendamustine is an efficient regimen even in high-risk patients (complex karyotype, PFS<24mo, TTNT<24mo). These data are important since this immunochemotherapy is now used as the backbone for combination with new compounds (ibrutinib, GS1101, GDC-199).

Disclosures:
Aurran-Schleinitz: Roche: Honoraria. Leblond:Roche: Advisory Board Other, Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Mundipharma: Honoraria; Janssen-Cilag: Honoraria.