Belantamab Mafodotin in Patients with Relapsed and Refractory Multiple Myeloma Who Have Received at Least One Proteasome Inhibitor, One Immunomodulatory Agent and One Anti-CD38 Monoclonal Antibody: A Retro-Prospective Italian Observational Study

Despite a significant improved outcome in Multiple Myeloma (MM) patients due to introduction of immunomodulatory drugs (IMiDs), proteasome inhibitors (PIs), and monoclonal antibodies (mAbs), occurrence of resistance to these agents results in a poor survival with the need for effective therapies in this setting. Belantamab mafodotin (belamaf) represents the first-in-class antibody-drug conjugate (ADC) targeting B-cell maturation antigen (BCMA) to be approved for treatment of relapsed/refractory MM (rrMM) patients who have previously received at least four lines of therapy after it demonstrated meaningful activity as monotherapy in the phase II DREAMM-2 study.

Real-world data of belamaf use is scarce since the number of patients in the study cohorts are low. We carried out a retro-prospective study aiming to evaluate efficacy and safety of belamaf monotherapy in RRMM patients treated according to compassionate use programmes as Named Patient Program (NPP) and Expanded Access Program (EAP) in 60 Italian centers under the aegis of European Myeloma Network (EMN). The primary endpoint of this study was the rate of patients achieving a clinical benefit (at least minimal response according to IMWG criteria). Secondary endpoints were ORR (at least PR), duration of response (DoR), progression-free survival (PFS) and overall survival (OS). Eligible patients must be ≥18 years of age with a MM diagnosis according to IMWG criteria; they must have received at least 4 previous therapies and be refractory to at least one proteasome inhibitor, one immunomodulatory drug, and one anti-CD38 antibody. Moreover, patients had to have an ECOG performance status ≤ 2 and adequate organs function.

Overall, 182 patients have been treated with belamaf within the compassionate use programmes, 138 in the NPP program and 44 in the EAP program. In July 2022, 23 patients are still receiving therapy with belamaf (7 are from NPP program). Notably, 2 patients have received 9 belamaf cycles, 8 patients received more than 11 cycles, 8 patients more than 15 cycles and 5 patients at least 20 cycles. Moreover, one patient was given 34 cycles and another 36 ones.

This is the largest real-life study on belamaf monotherapy in rrMM. Data on efficacy and safety will be detailed at the meeting.

Offidani:ABBVIE: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene (Bristol Myers Squibb): Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; GSK: Honoraria, Membership on an entity's Board of Directors or advisory committees; JANSEEN: Honoraria, Membership on an entity's Board of Directors or advisory committees; ROCHE: Honoraria, Membership on an entity's Board of Directors or advisory committees; SANOFI: Honoraria, Membership on an entity's Board of Directors or advisory committees; TAKEDA: Honoraria, Membership on an entity's Board of Directors or advisory committees. Cavo:Janssen: Honoraria, Speakers Bureau; AbbVie, Amgen, Bristol Myers Squibb/Celgene, Pfizer, GlaxoSmithKline, Sanofi, Roche, Takeda: Consultancy, Honoraria. Boccadoro:Sanofi: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; AbbVie: Honoraria; GlaxoSmithKline: Membership on an entity's Board of Directors or advisory committees; Mundipharma: Research Funding; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Honoraria, Research Funding; Bristol Myers Squibb: Honoraria, Research Funding. Petrucci:Celgene/Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support for attending meetings and/or travel; Janssen-Cilag: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support for attending meetings and/or travel; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support for attending meetings and/or travel; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support for attending meetings and/or travel; GlaxoSmithKline: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support for attending meetings and/or travel; Roche: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees. Belotti:Janssen: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees.