Management of Relapsed and Refractory Multiple Myeloma
Journal of Clinical Outcomes Management. 2016 October;23(10)
References
For patients who enjoyed a long remission after any particular chemotherapy regimen with good tolerability and with indolent features at the time of relapse, re-treating with the same regimen can be considered, although nowadays with so many new and highly potent agents available such “backtracking” is less common and some studies suggest that employing new agents may be beneficial. As an example, in the randomized ENDEAVOR study of bortezomib + dexamethasone versus carfilzomib + dexamethasone in RRMM, 54% of patients had been exposed to bortezomib whereas virtually none had received carfilzomib prior to study enroll-ment. Among those patients with prior bortezomib exposure, median progression-free survival was 15.6 versus 8.1 months (hazard ratio 0.56, [95% confidence interval 0.44 to 0.73]) for carfilzomib versus bortezomib, respectively. Follow-up was too immature for definitive conclusions to be drawn about overall survival, but the substantial difference in progression-free survival provides a compelling argument for using carfilzomib instead of going back to bortezomib for patients with prior bortezomib exposure [36].
Managing RRMM is by necessity highly individualized and so it is difficult in an article to summarize an algorithm. Data from some of the most relevant trials are presented in Table 2 [11,35–51]. In general, therapy for relapse is dictated largely by what drugs a patient has been treated with before. At the time of first relapse, most patients have been treated previously with some combination of bortezomib and/or lenalidomide, and many patients are on one if not both drugs as maintenance.
For patients who are fit and not very old, we generally employ triplet re-induction. For the large number of these patients who were previously exposed to both lenalidomide and bortezomib, including as part of a maintenance strategy, outside of clinical trials we routinely use carfilzomib + pomalidomide + dexamethasone [41]. For patients who are lenalidomide-naïve but bortezomib-exposed, we often employ carfilzomib + lenalidomide + dexamethasone based on the phase 3 ASPIRE trial, which showed a significantly improved progression-free survival with carfilzomib + lenalidomide + dexamethasone versus lenalidomide + dexamethasone [47]. For patients who have previously received lenalidomide but not bortezomib, we consider pomalidomide + bortezomib + dexamethasone [52]. These regimens take advantage of the arguably most potent, most proven drugs in treating RRMM, namely proteasome inhibitors (bortezomib and carfilzomib) and immunomodulatory agents (lenalidomide and pomalidomide).
For patients who are more vulnerable to toxicity due to advanced age or comorbidities, we consider less intensive regimens, including dose-reduced triplets or doublets. Patients who had received lenalidomide-based combinations but not bortezomib are considered for a bortezomib-based re-induction, including bortezomib + dexamethasone alone. In the case of someone who had initially received a bortezomib-based combination but no lenalidomide, the new drugs are viable options: ixazomib [53] or elotuzumab [43] can both be added to standard lenalidomide + dexamethasone, with expectations of increasing response rates and progression-free survival and an acceptably low increased risk of severe toxicity. Ixazomib + lenalidomide + dexamethasone also has the benefit of being all-oral. For patients with bortezomib- and lenalidomide-exposed RRMM, using carfilzomib [54] or pomalidomide [55] with dexamethasone is reasonable.
