The importance of complete response in outcomes in myeloma

[Multiple myeloma: Maintenance therapy after autologous hematopoietic stem cell transplantation, depending on minimal residual disease]

AIM

To determine the efficiency of maintenance therapy with bortezomib in patients with multiple myeloma (MM) who have achieved complete remission (CR) after autologous hematopoietic stem cell (auto-HSCT), depending on the presence of minimal residual disease (MRD).

SUBJECTS AND METHODS

In January 2014 to February 2016, fifty-two MM patients (19 men and 33 women) aged 24 to 66 years (median 54 years), who had achieved CR after auto-HSCT, were randomized to perform maintenance therapy with bortezomib during a year. On day 100 after auto-HSCT, all the patients underwent immunophenotyping of bone marrow plasma cells by 6-color flow cytometry to detect MRD. Relapse-free survival (RFS) was chosen as a criterion for evaluating the efficiency of maintenance therapy.

RESULTS

After auto-HSCT, MRD-negative patients had a statistically significantly higher 2-year RFS rate than MRD-positive patients: 52.9% (95% confidence interval (CI), 35.5 to 70.5%) versus 37.2% (95% CI, 25.4 to 49.3%) (p=0.05). The presence of MRD statistically significantly increased the risk of relapse (odds ratio 1.7; 95% CI, 1.2 to 3.4; p=0.05). Two-year cumulative risk of relapse (using the Kaplan-Meier) after auto-HSCT did not statistically significantly differ in MRD-negative patients receiving (n=15) and not receiving (n=10) maintenance therapy with bortezomib (p=0.58). After completion of maintenance treatment, 42% of the MRD-positive patients achieved a negative status. In the MRD-positive patients who had received maintenance therapy, the average time to recurrence was 5 months longer than that in the naïve patients: 17.3 versus 12.3 months.

CONCLUSION

The MRD status determined in MM patients who have achieved CR after auto-HSCT is an important factor for deciding on the use of maintenance therapy.

Association between complete response and outcomes in transplant-eligible myeloma patients in the era of novel agents

OBJECTIVES

Achieving complete response (CR) has been linked to improved progression-free (PFS) and overall (OS) survival in myeloma. A meta-analysis was conducted to investigate whether this holds true in the era of novel agents (bortezomib, lenalidomide, thalidomide).

METHODS

A total of 24 studies in newly diagnosed patients undergoing autologous stem cell transplantation (ASCT) that reported associations between responses and long-term outcomes (PFS/OS rates post-ASCT by response, or hazard ratios with 95% confidence intervals from Cox models) were identified and analyzed.

RESULTS

Achievement of CR vs. <CR post-ASCT reduced risk of progression/death by 38% [risk ratio (RR): 0.62, P < 0.0001]; risk of death was 41% lower (RR: 0.59, P < 0.0001). Subgroup meta-analyses showed significant PFS risk reduction with CR post-ASCT with novel (RR: 0.32, P < 0.006) and non-novel (RR: 0.72, P < 0.0001) agents, and corresponding OS risk reduction with novel (RR: 0.33, P = 0.0013) and non-novel (RR: 0.64, P < 0.0001) agents. Risk reduction was greater with novel vs. non-novel agents (PFS: P = 0.047; OS: P = 0.058).

CONCLUSIONS

Achieving CR during first-line therapy remains important in the novel-agent era; magnitude of association between achieving CR and outcomes appears higher for CR obtained using novel vs. non-novel agents.

Lenalidomide before and after Autologous Hematopoietic Stem Cell Transplantation in Multiple Myeloma

Although multiple myeloma remains incurable outside of allogeneic hematopoietic stem cell transplantation, novel agents made available only in the last few decades have nonetheless tremendously improved the landscape of myeloma treatment. Lenalidomide, of the immunomodulatory class of drugs, is one of those novel agents. In the non-transplant and relapsed/refractory settings, lenalidomide clearly benefits patients in terms of virtually all meaningful outcomes including overall survival. Data supporting the usage of lenalidomide as part of treatment approaches incorporating high-dose chemotherapy with autologous stem cell support (ASCT) are less mature as pertains to such long-term outcomes and toxicity, and lenalidomide is not currently approved by regulatory agencies for use in the context of ASCT in either the United States or Europe. That said, relatively preliminary efficacy data describing lenalidomide as a component of ASCT-based treatment approaches to MM are indeed promising, and consequently lenalidomide's role in ASCT-based treatment strategies is growing. In this review we summarize existing data that pertains to lenalidomide in the specific context of ASCT, and we share our thoughts on how our own group applies these data to approach this complex issue clinically.

Lower dose dexamethasone/thalidomide and zoledronic acid every 3 weeks in previously untreated multiple myeloma

BACKGROUND

Physicians in Asia have anecdotally reported that Asian patients with multiple myeloma (MM) are frequently intolerant of conventional doses of dexamethasone (Dex) and/or thalidomide (Thal). Since zoledronic acid (Zol) has an anti-MM effect in preclinical studies, we investigated whether the approved 3-times-weekly Zol combined with lower dose Dex/Thal could be an effective and better tolerated regimen in Asian patients.

PATIENTS AND METHODS

In this first Asian cooperative multicenter phase II study, previously untreated patients with MM (N = 44) received up to 6 cycles of 3-times-weekly low-dose Dex/Thal and 4 mg Zol (the dtZ regimen). Response was graded using Bladé criteria.

RESULTS

The average doses of Dex and Thal administered were 185.2 mg/month; and 87.5 mg/day, respectively. Thirty-nine (88.6%) patients demonstrated at least a partial response (PR), including 18.2% very good partial response (VGPR), 15.9% near complete response (nCR) and 18.2% complete response (CR). Achievement of CR/nCR was related to significant (P < .05), rapid, and sustained inhibition of osteoclasts (OCs) and OC precursors (pOCs) by Zol. Sepsis was the most frequently reported serious toxicity, contributing to 3 of 4 deaths. Importantly, there was no peripheral neuropathy, osteonecrosis of the jaw, or nephrotoxicity.

CONCLUSION

We conclude that the dtZ regimen is an effective and well-tolerated regimen for Asian patients with newly diagnosed MM. The high rate of VGPR/nCR/CR suggests that Zol could have a clinically relevant anti-MM effect. Since infections are the most frequent adverse event, it is probably wise to further lower the dose of Dex in future studies.

Approach to the treatment of multiple myeloma: a clash of philosophies

In this Perspective, we summarize some of the most contentious issues surrounding diagnosis and treatment of myeloma. We outline how a fundamental clash of philosophies, cure versus control, may be at the heart of many of the controversies. From the very definition of the disease to risk stratification to the validity of current clinical trial endpoints, we highlight the major areas of debate and provide alternative viewpoints that have implications for trial design and interpretation, as well as clinical practice.