Elranatamab in Japanese patients with relapsed/refractory multiple myeloma: results from MagnetisMM-2 and MagnetisMM-3.

BACKGROUND: Despite advances, most patients with multiple myeloma (MM) experience relapse and repeat multiple treatment lines, highlighting an unmet need for patients with relapsed or refractory MM (RRMM). Bispecific antibodies are a new option, but their efficacy and safety in Japanese patients are unknown. METHODS: This was an analysis of Japanese patients receiving elranatamab monotherapy in MagnetisMM-2 (NCT04798586) and MagnetisMM-3 (NCT04649359). Both studies evaluated a priming dose regimen of elranatamab followed by weekly subcutaneous doses, in patients with disease progression while receiving or who were intolerant to ≥3 prior therapies (≥1 proteasome inhibitor, ≥1 immunomodulatory drug and ≥1 anti-CD38 monoclonal antibody). The primary endpoints were dose limiting toxicities (DLTs) in MagnetisMM-2 and confirmed objective response rate (ORR) in MagnetisMM-3. In both, key secondary endpoints included safety, tolerability, duration of response, time to response, progression-free survival and overall survival. RESULTS: In MagnetisMM-2 (N = 4) and MagnetisMM-3 (n = 12), median ages were 68.5 and 66.5 years, respectively. No DLTs were observed in MagnetisMM-2. ORRs were 50.0% (95% CI, 6.8-93.2) and 58.3% (95% CI, 27.7-84.8) in MagnetisMM-2 and MagnetisMM-3, respectively. All patients experienced treatment-emergent adverse events in MagnetisMM-2 (grade 3/4: 75.0%) and MagnetisMM-3 (grade 3/4: 100%); cytokine release syndrome occurred in 100% (grade 3/4: 25.0%) and 58.3% (no grade 3/4) of patients, respectively. Neither study reported immune effector cell-associated neurotoxicity syndrome. CONCLUSIONS: No new safety signals were observed, and ORRs were similar to that of the overall MagnetisMM-3 trial population, supporting further studies of elranatamab in Japanese patients with RRMM. ClinicalTrials.gov identifier: NCT04798586 (MagnetisMM-2), NCT04649359 (MagnetisMM-3).

[Multiple myeloma with IgH::MYC and multiple extramedullary lesions].

A 41-year-old woman with right shoulder pain was found to have multiple tumors with osteolysis and M-proteinemia. Abnormal plasma cells (CD38+, CD138+, Igλ≫κ) were detected in 1.4% of bone marrow nucleated cells, and G-banding analysis revealed a 46,XX,t (8;14), (q24;q32) karyotype in 4 of 20 cells analyzed. A biopsy specimen from an extramedullary lesion had a packed proliferation of aberrant plasmacytoid cells with positive IgH::MYC fusion signals on fluorescence in situ hybridization. The patient was diagnosed with symptomatic multiple myeloma and treated with the BLd regimen, which significantly reduced M protein levels. Extramedullary lesions were initially reduced, but increased again after four cycles. The lesions disappeared with subsequent EPOCH chemotherapy and radiation, and complete remission was confirmed. The patient was then treated with high-dose chemotherapy with autologous peripheral blood stem cell transplantation. Complete remission was maintained for over one year with lenalidomide maintenance therapy. A solitary IgH::MYC chromosomal translocation is extremely rare in multiple myeloma and may be associated with high tumor proliferative capacity, multiple extramedullary lesions, and poor prognosis. Combined therapeutic modalities with novel and conventional chemotherapy and radiation might be a promising treatment strategy for patients with this type of multiple myeloma.

Successful haploidentical hematopoietic stem cell transplantation for paroxysmal nocturnal hemoglobinuria with severe pancytopenia developed after long-term aplastic anemia treatment.

Haploidentical hematopoietic stem cell transplantation (HSCT) with posttransplant cyclophosphamide is an alternative treatment for aplastic anemia-paroxysmal nocturnal hemoglobinuria (PNH) syndrome with poor prognostic factors. Ravulizumab treatment for PNH before HSCT might have a beneficial effect.

Plasma Venetoclax Concentrations in Patients with Acute Myeloid Leukemia Treated with CYP3A4 Inhibitors.

Venetoclax (VEN) is used in patients with acute myeloid leukemia (AML) and is primarily metabolized by CYP3A4, a major drug-metabolizing enzyme. Patients with AML simultaneously administered VEN and CYP3A4 inhibitors require a more appropriate management of drug-drug interactions (DDIs). Here, we report two cases of patients with AML (54-year-old man and 22-year-old woman) administrated VEN and CYP3A4 inhibitors, such as posaconazole, cyclosporine, or danazol. In the first case, we evaluated the appropriateness of timing for adjusting VEN dosage subsequent to the cessation of posaconazole. Consequently, modifying the VEN dosage in conjunction with the cessation of Posaconazole simultaneously may result in elevated plasma VEN levels. In the second case, plasma VEN concentrations were markedly elevated when co-administered with several CYP3A4 inhibitors. Additionally, in vitro assays were conducted for reverse translational studies to analyze CYP3A4 inhibition. CYP3A4 inhibition by combinatorial administration of cyclosporine A and danazol was demonstrated in vitro, which potentially explains the increasing plasma VEN concentrations observed in clinical settings. Although the acquisition of therapeutic effects is a major priority for patients, frequent therapeutic drug monitoring and dosage adjustments considering DDIs would be important factors in chemotherapy.