Session: 623. Mantle Cell, Follicular, and Other Indolent B-Cell Lymphoma—Clinical Studies: Poster II
Hematology Disease Topics & Pathways:
Biological, antibodies, Adult, Diseases, Mantle Cell Lymphoma, Therapies, Combinations, B-Cell Lymphoma, enzyme inhibitors, Lymphoid Malignancies, Study Population, Clinically relevant
Methods: Patients with MCL, relapsing after or refractory to at least one rituximab-containing chemotherapy regimen, WHO PS 0-3, and measurable disease were eligible. The primary endpoint was maximal overall response rate (ORR) measured with CT and PET/CT. Minimal residual disease (MRD) monitoring by PCR was performed during follow-up, according to EuroMRD criteria. Ion Torrent sequencing of the most frequently mutated genes in MCL was performed on frozen tumor cells from bone marrow at time of relapse. Health-related quality of life was assessed by the EORTC-QLQ C30 questionnaire before and during treatment.
Treatment schedule: Induction phase: Up to twelve 28-day cycles with: Lenalidomide 15 mg p o daily, days 1-21, Ibrutinib 560 mg p o days 1-28, Rituximab 375 mg/m2 i v day 1 in cycle 1, then 1400 mg s c (or 375 mg/m2i v) days 8, 15 and 22 in cycle 1, then day 1 in cycles 3, 5, 7, 9 and 11. Maintenance phase: For patients in CR, PR or SD, not in need of other treatment, given until progression, cycle duration 56 days. Ibrutinib: 560 mg p o days 1-56, 2. Rituximab 1400 mg s c (or 375 mg/m2i v) day 1 of each cycle.
Results: Accrual of 50 pts was completed in June 2016, at 10 centres in Sweden, Norway, Denmark and Finland. The median age was 69.5 years, with a median MIPI score of 6.2. Patients had received a median of two previous regimens, four had progressed after single agent ibrutinib, and three had received prior allo-SCT. A TP53 mutation was detected in 11 of 49 evaluable cases (22%), 8 cases were of blastoid/pleomorphic histology, and 22 of 40 evaluable cases had a Ki67 >30%. Treatment emergent-AEs of any grade in ≥20% of patients were rash (24%) and fatigue (20%). Five pts (10%) experienced rash grade 3, mainly during cycle 1. Hematological toxicity was generally of low grade, apart from grade 3-4 neutropenia in 5 patients. One patient died due to possible treatment-related toxicity (septic shock). In total, 27 patients achieved CR (54%) and 10 PR (20%). Among evaluable patients with a TP53 mutation, blastoid/pleomorphic histology or Ki67 >30%, the CR rates were 7/11 (64%), 15/8 (62%) and 11/22 (50%), respectively. After a median follow-up of 40 months, the median PFS is 18 months (95% CI 6.5-28), and median OS 47 months (95% CI 30-64). Patients with a detectable TP53 mutation at relapse (n=11) had a median PFS of 13 months (95% CI 4.2-21), whereas pts without a TP53 mutation had a median PFS of 34 months (95% CI 8.3-60). Of the 28 patients evaluable for MRD at 6 months, 15/27 (56%) patients achieved molecular remission in blood and 12/28 (43%) in bone marrow. After 12 months, MRD-negativity in BM was 68% (13/19). Out of 4 patients with TP53-mutated MCL, 2 were MRD-negative in BM after 12 months, as well as 2 out of 4 patients with blastoid/pleomorphic histology. By self-reported HRQOL, a lower level of emotional functioning (EF), as well as a higher level of pain (PA) at baseline, was associated with inferior PFS. In addition, low EF was associated with inferior OS. By a Cox regression multivariable analysis, including MIPI, TP53, histology, Ki67, EF and PA, only MIPI was prognostic for PFS or OS with this regimen.
Conclusions: The combination of ibrutinib, lenalidomide and rituximab has been shown to be an active and well tolerated regimen in this cohort of high risk R/R MCL, associated with a high rate of molecular remission. The activity in TP53 mutated MCL is lower than in unmutated disease, but this regimen may still serve as an option for a bridge to an allogeneic transplantation or CAR-T therapy in this category of patients.
Disclosures: Jerkeman: Celgene: Research Funding; Roche: Research Funding; Gilead: Research Funding; Abbvie: Research Funding; Janssen: Research Funding. Hutchings: Genmab: Honoraria; Genmab: Consultancy; Takeda: Consultancy; Roche: Research Funding; Celgene: Research Funding; Daiichi: Research Funding; Sankyo: Research Funding; Genmab: Research Funding; Janssen: Research Funding; Novartis: Research Funding; Sanofi: Research Funding; Takeda: Research Funding; Roche: Honoraria; Roche: Consultancy; Takeda: Honoraria.
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