Significance of Salvage Autologous Stem Cell Transplantation for Relapsed Multiple Myeloma: A Nationwide Retrospective Study in Japan

Practice patterns and outcomes for triple-class exposed patients with relapsed/refractory multiple myeloma in Japan

Aim: Treatment options for triple-class exposed (TCE) patients with multiple myeloma (MM) in Japan are limited. Materials & methods: Retrospective observational study using the Medical Data Vision database (April 2008-April 2021). Eligible adults with MM received a new post-TCE treatment. Treatments, healthcare resource utilization (HCRU) and costs (per patient per month [PPPM]) were analyzed with subgroup analyses by prior stem cell transplantation (SCT vs No SCT). Results: Of 459 TCE patients, 216 (47%) had post-TCE treatment of whom 194 (90%) had no prior SCT. Median duration of the first post-TCE line of therapy (LOT) was 2 months; 49% of No SCT patients received a subsequent LOT. Total healthcare costs were comparable between No SCT and SCT groups (¥1.3 million PPPM each; US$12,328 and $12,391, respectively), driven by treatment costs. Median post-index overall survival (n = 216) was 15.8 months (95% CI: 10.5, 22.3). Conclusion: New treatments with better effectiveness are needed for patients with TCE MM in Japan.

Carfilzomib and dexamethasone maintenance following salvage ASCT in multiple myeloma: A randomised phase 2 trial by the Nordic Myeloma Study Group

Objective

We investigated the efficacy and safety of carfilzomib‐containing induction before salvage high‐dose melphalan with autologous stem‐cell transplantation (salvage ASCT) and maintenance with carfilzomib and dexamethasone after salvage ASCT in multiple myeloma.

Methods

This randomised, open‐label, phase 2 trial included patients with first relapse of multiple myeloma after upfront ASCT who were re‐induced with four cycles of carfilzomib, cyclophosphamide and dexamethasone. Two months after salvage, ASCT patients were randomised to either observation or maintenance therapy with iv carfilzomib 27 → 56 mg/sqm and p.o. dexamethasone 20 mg every second week. The study enrolled 200 patients of which 168 were randomised to either maintenance with carfilzomib and dexamethasone (n = 82) or observation (n = 86).

Results

Median time to progression (TTP) after randomisation was 25.1 months (22.5‐NR) in the carfilzomib‐dexamethasone maintenance group and 16.7 months (14.4–21.8) in the control group (HR 0.46, 95% CI 0.30–0.71; P = .0004). The most common adverse events during maintenance were thrombocytopenia, anaemia, hypertension, dyspnoea and bacterial infections.

Conclusion

In summary, maintenance therapy with carfilzomib and dexamethasone after salvage ASCT prolonged TTP with 8 months. The maintenance treatment was in general well‐tolerated with manageable toxicity.

Role of Stem Cell Transplantation in Multiple Myeloma

Autologous stem cell transplantation (auto-SCT) has been the standard of care in eligible newly diagnosed multiple myeloma (MM) patients. Outcomes of patients with MM have improved significantly due to the advent of several novel drugs. Upfront use of these drugs in induction therapy has significantly increased the rate and depth of responses that have translated into longer remission and survival. This has now raised a debate regarding the role and relevance of auto-SCT in the management of myeloma. However, clinical trials have confirmed the utility of auto-SCT even in the era of novel drugs. Tandem auto-SCT followed by maintenance has shown a progression-free survival (PFS) benefit in high-risk MM, and hence can be considered in young and fit patients with high-risk disease. Auto-SCT has the advantages of resetting the bone marrow microenvironment, short-lived toxicity compared to the long-term physical and financial toxicities of continued chemotherapy in the absence of SCT, very low transplant-related mortality (TRM) in high volume centers, and providing longer disease-free survival when followed by maintenance therapy. Allogeneic SCT is one potentially curative option for MM, albeit with an increased risk of death due to high TRM. Strategies to modulate the graft-versus-host disease (GVHD) while maintaining or improving the graft-versus-myeloma (GVM) effect could place allogeneic SCT back in the treatment armamentarium of MM.

Therapy for relapsed multiple myeloma

Despite significant progress in our understanding and the development of novel therapies, most patients with multiple myeloma will experience relapse of their disease. Therapy of relapsed myeloma has improved due to the availability of novel agents that are highly active against the disease. However, the selection of therapy can be challenging due to the emergence of toxicities, comorbidities and frailty. In the following we discuss our approach to the treatment of the patient with relapsed myeloma.