Long-Term Follow-up of CALGB (Alliance) 100001: Autologous Followed by Nonmyeloablative Allogeneic Transplant for Multiple Myeloma

Ciltacabtagene Autoleucel in Patients With Prior Allogeneic Stem Cell Transplant in the CARTITUDE-1 Study

BACKGROUND

Patients with prior allogeneic stem cell transplant (alloSCT) are typically excluded from trials of chimeric antigen receptor (CAR) T cell therapies, because their engineered cells may include allogeneic T cells. Ciltacabtagene autoleucel (cilta-cel) demonstrated early, deep, durable responses and manageable safety in heavily pretreated relapsed/refractory multiple myeloma patients. We retrospectively analyzed patients who received alloSCT prior to cilta-cel in CARTITUDE-1.

PATIENTS AND METHODS

Patients eligible for CARTITUDE-1 were ≥18 years, had ≥3 prior lines of therapy (LOT) or were double refractory to a proteasome inhibitor (PI) and immunomodulatory drug (IMiD) and had received a PI, IMiD, and anti-CD38 antibody. Patients with active graft-versus-host disease (GVHD) or had alloSCT within 6 months before apheresis were excluded. Patients received cilta-cel 5 to 7 days after lymphodepletion.

RESULTS

Patients (N = 7) received median 9 prior LOTs (range, 6-14); median time since alloSCT was 5.1 years (range, 2.7-6.2). At median follow-up 27.7 months after cilta-cel infusion, overall response rate was 85.7% (n = 6). The safety profile was generally consistent with patients without alloSCT as prior therapy (cytokine release syndrome, 85.7% vs. 95.6%, respectively; immune effector cell-associated neurotoxicity syndrome, 14.3% vs. 16.7%). One patient with prior alloSCT had grade 3 movement and neurocognitive treatment-emergent adverse events/parkinsonism. No GVHD cases were reported. Two patients died due to adverse events (treatment-related lung abscess; unrelated liver failure).

CONCLUSION

Cilta-cel efficacy and safety were comparable between CARTITUDE-1 patients with and without prior alloSCT. Additional studies are needed to fully elucidate the suitability of CAR-T cell therapy in the post-alloSCT setting.

Revisiting the Role of Alkylating Agents in Multiple Myeloma: Up-to-Date Evidence and Future Perspectives

From the 1960s to the early 2000s, alkylating agents (e.g., melphalan, cyclophosphamide, and bendamustine) remained a key component of standard therapy for newly-diagnosed or relapsed/refractory multiple myeloma (MM). Later on, their associated toxicities (including second primary malignancies) and the unprecedented efficacy of novel therapies have led clinicians to increasingly consider alkylator-free approaches. Meanwhile, new alkylating agents (e.g., melflufen) and new applications of old alkylators (e.g., lymphodepletion before chimeric antigen receptor T-cell [CAR-T] therapy) have emerged in recent years. Given the expanding use of antigen-directed modalities (e.g., monoclonal antibodies, bispecific antibodies, and CAR-T therapy), this review explores the current and future role of alkylating agents in different treatment settings (e.g., induction, consolidation, stem cell mobilization, pre-transplant conditioning, salvage, bridging, and lymphodepleting chemotherapy) to ellucidate the role of alkylator-based regimens in modern-day MM management.

Cellular Immunotherapies for Multiple Myeloma: Current Status, Challenges, and Future Directions

Multiple myeloma (MM) remains incurable due to relapse, although the use of proteasome inhibitors, immunomodulatory drugs, CD38-targeting antibodies, and autologous stem cell transplantation (auto-SCT) significantly improve the clinical outcomes of patients with newly diagnosed MM. In recent years, the introduction of chimeric antigen receptor T-cell (CAR T-cell) therapy has brought hope to patients with refractory and relapsed MM. The graft-versus-myeloma effect of allogeneic SCT provides the possibility for curing a subset of MM patients. In this review, we summarize the recent advances and challenges of cellular immunotherapies for MM, focusing on auto-SCT, allogeneic SCT, and CAR T-cell approaches. We also discuss future directions, and propose a specific algorithm for cellular therapies for MM and probability of minimal residual disease-directed therapy.

Allogeneic Stem Cell Transplantation in Multiple Myeloma

The development of new inhibitory and immunological agents and combination therapies significantly improved response rates and survival of patients diagnosed with multiple myeloma (MM) in the last decade, but the disease is still considered to be incurable by current standards and the prognosis is dismal especially in high-risk groups and in relapsed and/or refractory patients. Allogeneic hematopoietic stem cell transplantation (allo-SCT) may enable long-term survival and even cure for individual patients via an immune-mediated graft-versus-myeloma (GvM) effect, but remains controversial due to relevant transplant-related risks, particularly immunosuppression and graft-versus-host disease, and a substantial non-relapse mortality. The decreased risk of disease progression may outweigh this treatment-related toxicity for young, fit patients in high-risk constellations with otherwise often poor long-term prognosis. Here, allo-SCT should be considered within clinical trials in first-line as part of a tandem approach to separate myeloablation achieved by high-dose chemotherapy with autologous SCT, and following allo-SCT with a reduced-intensity conditioning to minimize treatment-related organ toxicities but allow GvM effect. Our review aims to better define the role of allo-SCT in myeloma treatment particularly in the context of new immunomodulatory approaches.

The Role of Allogeneic Stem Cell Transplantation in Multiple Myeloma: A Systematic Review of the Literature

Multiple myeloma (MM) is an indolent B-cell malignancy, where treatment is aimed at preventing organ dysfunction from light chain accumulation (slowing disease progression) and inducing remission. Allogeneic stem cell transplant (allo-SCT), through graft versus myeloma (GVM) effects, has the potential to induce remission to a potentially curative-like state. In this systematic review, we aimed to understand this relationship to the risks and severity of disease in categorized patients and gain an updated comprehension of the future of allo-SCT in MM treatment. We conducted this review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and searched the PubMed database to obtain the specified literature with both the use of keywords and Medical Subject Headings (MeSH). A total of 16 relevant articles were included for discussion after the quality appraisal was completed, as appropriate, by either the Cochrane tool or Newcastle-Ottawa checklist. Our review concludes that while allo-SCT may benefit high-risk patients, successful procedures may incorporate a tandem autologous hematopoietic stem cell transplant approach in combination with novel pharmacologic contributions for which there is an observed synergy in the modulation of the immunologic microenvironment. Furthermore, tailored patient selection by evaluating pre-transplant factors including high-risk cytogenetics, age, and pre-salvage International Staging System (ISS) can predict post-transplantation success including non-relapse mortality. Successive research should continue to revise and update treatment options as the evolving therapeutic drug regimens may change over the course of indolent disease.