Rituximab, Bendamustine and Cytarabine Followed By Venetoclax (V-RBAC) in High-Risk Elderly Patients with Mantle Cell Lymphoma
Authors: Visco Carlo , Tabanelli Valentina , Peracchio Claudia , Evangelista Andrea , Tisi Maria Chiara , Merli Anna , Fraenza Costanza , Fiori Stefano , Re Alessandro , Castellino Claudia , Zilioli Vittorio Ruggero , Piazza Francesco , Corradini Paolo , Hohaus Stefan , Musuraca Gerardo , Ferla Valeria , Puccini Benedetta , Cavallo Federica , Ballerini Filippo , Sciarra Roberta , Di Rocco Alice , Arcari Annalisa , Boccomini Carola , Merli Francesco , Gini Guido , Tani Monica , Bruna Riccardo , Pavone Vincenzo , Ferreri Andrés J M , Santoro Armando , Patti Caterina , Loseto Giacomo , Ladetto Marco , Merli Michele , Spina Michele , Zinzani Pier Luigi , Stefani Pietro Maria , Usai Sara Veronica , Stelitano Caterina , Volpetti Stefano , Pileri Stefano A , Balzarotti Monica 
Published: November 2021

Abstract
The R-BAC regimen is considered among standard first-line treatment for elderly fit patients with mantle cell lymphoma (MCL). In the previous R-BAC500 FIL trial, patients with the blastoid variant and/or high Ki67 proliferative index (High Risk - HR-) had a significantly higher risk of progression (2-years PFS of 40%), as compared to classical histologies and low proliferative index (Low Risk -LR-). When treated with R-BAC, LR patients had excellent outcome (median PFS not reached after 7 years), although no maintenance therapy was delivered. For this reason we designed a phase 2 trial that enrolled patients from 35 centers of the Fondazione Italiana Linfomi (FIL). At study entry, patients were centrally reviewed and stratified as "low risk (LR)", or "high risk (HR)", depending on morphology (blastoid versus others), Ki67 expression (≥30% versus others), TP53 mutation/TP53 deletions (present versus not). Patients with any of the three risk factors were classified as HR. The primary endpoint was 2-years progression-free survival (PFS) for the HR patients. Patients had to be aged ≥65 years and fit according to the geriatric CGA assessment, or age ≤64 years if not eliglible to high-dose chemotherapy plus transplantation. Asymptomatic patients with non-nodal disease were excluded. Treatment consisted of 6 cycles of R-BAC (rituximab 375 mg/m2 d 1; bendamustine 70 mg/m2 d 1,2; cytarabine 500 mg/m2 d 1,2,3) for LR patients. HR patients received abbreviated induction with a maximum of 4 R-BAC followed by consolidation (4 months, 800 mg/d), and maintenance (20 months, 400 mg/d) with venetoclax. First patient was included on the 3rd of september, 2018, and last patient on the 20th of july, 2021. Overall, 140 patients were enrolled, of whom 52 were HR (37%). Median age was 72 (range 57-79), and 75% were males. The prevalence of TP53 mutations and deletions in the whole series was 21%, and 13%, respectively; Ki67 was ≥30% in 24%, and the blastoid variant was diagnosed in 9%. Demographic characteristics of HR versus LR patients (127 patients with available data at the present time) are reported in Table 1A. Median follow-up was 9 months (range 0-34). The two groups (HR and LR) had similar age, gender, and MIPI, but differed for LDH, and SUVmax at diagnosis, both being significantly more elevated in the HR group. The VR-BAC trial represents the first prospective study that stratified patients with MCL to different frontline treatments according to centralized on-time evaluation of the risk profile. We have shown that almost 40% of elderly patients with MCL in need of treatment have HR features. Data on tolerance, and tumor response will be presented at the meeting.
Figure 1 Figure 1.

Disclosures
Tisi: GILEAD: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; BWS: Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees. Zilioli: Roche, Italfarmaco: Consultancy, Honoraria; MSD, Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations; Takeda: Other: travel expenses, accommodation; Gentili, Takeda, Gilead, Servier: Consultancy, Speakers Bureau. Corradini: AbbVie, ADC Theraputics, Amgen, Celgene, Daiichi Sankyo, Gilead/Kite, GSK, Incyte, Janssen, KyowaKirin, Nerviano Medical Science, Novartis, Roche, Sanofi, Takeda: Honoraria; BMS: Other: Travel and accommodation; Novartis; Gilead; Celgene: Consultancy, Other: Travel and accommodations; Amgen; Takeda; AbbVie: Consultancy, Honoraria, Other: Travel and accommodations; KiowaKirin; Incyte; Daiichi Sankyo; Janssen; F. Hoffman-La Roche; Kite; Servier: Consultancy; Sanofi: Consultancy, Honoraria; Incyte: Consultancy; AbbVie, ADC Theraputics, Amgen, Celgene, Daiichi Sankyo, Gilead/Kite, GSK, Incyte, Janssen, KyowaKirin, Nerviano Medical Science, Novartis, Roche, Sanofi, Takeda: Consultancy; Novartis, Janssen, Celgene, BMS, Takeda, Gilead/Kite, Amgen, AbbVie: Other: travel and accomodations. Musuraca: janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; incyte: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Puccini: Takeda: Membership on an entity's Board of Directors or advisory committees. Cavallo: Servier: Speakers Bureau; ROCHE: Membership on an entity's Board of Directors or advisory committees; Gilead: Speakers Bureau. Merli: EUSA Pharma: Other: Travel, Accomodations, Expenses; Roche: Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accomodations, Expenses; Takeda: Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accomodations, Expenses; MSD: Membership on an entity's Board of Directors or advisory committees; Gilead Science: Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accomodations, Expenses; Janssen: Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accomodations, Expenses; Celgene: Other: Travel, Accomodations, Expenses. Ferreri: PletixaPharm: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Research Funding; Beigene: Research Funding; Hutchison Medipharma: Research Funding; ADC Therapeutics: Research Funding; Adienne: Membership on an entity's Board of Directors or advisory committees; Genmab: Research Funding; Amgen: Research Funding; x Incyte: Membership on an entity's Board of Directors or advisory committees; Ospedale San Raffaele srl: Patents & Royalties; Pfizer: Research Funding. Santoro: AstraZeneca: Speakers Bureau; AbbVie: Speakers Bureau; Amgen: Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Speakers Bureau; Sandoz: Speakers Bureau; Eli-Lilly: Speakers Bureau; BMS: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Eisai: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gilead: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Speakers Bureau; Servier: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Speakers Bureau; Sanofi: Consultancy; Arqule: Consultancy, Speakers Bureau; Novartis: Speakers Bureau; Bayer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; MSD: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Zinzani: KYOWA KIRIN: Other, Speakers Bureau; SERVIER: Other: Advisory board, Speakers Bureau; SANDOZ: Other: Advisory board; TG Therapeutics: Other: Advisory board, Speakers Bureau; ROCHE: Other, Speakers Bureau; BMS: Other: Advisory board, Speakers Bureau; TAKEDA: Other: Advisory board, Speakers Bureau; MSD: Consultancy, Other: Advisory board, Speakers Bureau; NOVARTIS: Consultancy, Other, Speakers Bureau; EUSAPHARMA: Consultancy, Other, Speakers Bureau; Beigene: Other, Speakers Bureau; ADC Therap.: Other; Incyte: Other, Speakers Bureau; JANSSEN-CILAG: Other: Advisory board, Speakers Bureau; GILEAD: Other: Advisory board, Speakers Bureau; CELLTRION: Other: Advisory board, Speakers Bureau; VERASTEM: Consultancy, Other: Advisory board, Speakers Bureau.

OffLabel Disclosure:
Venetoclax is off-label in Italy in mantle cell lymphoma