Challenges and Strategies in the Management of Multiple Myeloma in the Elderly Population

PURPOSE OF REVIEW

Approximately one half of the patient-population in multiple myeloma (MM) is > 70 years at diagnosis. Despite notable strides in the management and improved survival, MM remains incurable, with an increasing proportion of elderly patients comprising the relapsed-refractory cohort.

RECENT FINDINGS

The arbitrary age cutoff at 65 years to define the elderly patient-population has evolved to a more nuanced categorization, incorporating a comprehensive assessment for determining frailty prior to commencing treatment. This step is critical in determining the therapy-intensity, including transplant-eligibility, to minimize toxicity. Dose-modifications are crucial, as the merits of continuous therapy are becoming evident in this patient-population. Bortezomib, lenalidomide, and dexamethasone (VRd) combination has emerged as standard of care for newly diagnosed MM. Fixed-duration Rd followed by reduced-dosed continuous R may be considered in select frail patients with standard-risk MM. Herein, we review the unique challenges encountered in elderly MM and discuss strategies for optimal management.

Carfilzomib: A new proteasome inhibitor for relapsed or refractory multiple myeloma

PURPOSE

The pharmacology, pharmacokinetics, clinical trials, adverse effects, dosage recommendations, and economic considerations of carfilzomib are reviewed.

SUMMARY

Multiple myeloma accounts for approximately 10-15% of all hematologic malignancies and 20% of blood-related cancer deaths. Despite recent advances in the treatment of multiple myeloma, most patients will eventually relapse, requiring further treatment. Carfilzomib is a new proteasome inhibitor that primarily targets the chymotrypsin-like activity of the 20S proteasome. The safety and efficacy of carfilzomib was demonstrated in the PX-171-003-A1 trial, a prospective phase II trial in patients with relapsed or refractory multiple myeloma who had received at least 2 prior therapies including a proteasome inhibitor and an immunomodulatory agent. Common adverse effects included fatigue (55.5%), anemia (46.8%), nausea (44.9%), and thrombocytopenia (36.3%). The recommended dose of carfilzomib for the first cycle is 20 mg/m(2) on 2 consecutive days each week for 3 weeks in a 4-week cycle escalating to 27 mg/m(2) for subsequent cycles. It is recommended that patients receive premedication with dexamethasone during cycle 1 and cycle 2 to minimize risk of infusion reactions.

CONCLUSION

Carfilzomib provides a clinical benefit to patients with relapsed or refractory multiple myeloma who have been previously treated with a proteasome inhibitor and an immunomodulatory agent.

Myeloma kidney: improving clinical outcomes?

Renal impairment is a common complication of multiple myeloma, affecting 20% to 40% of new cases (depending on the definition). Most cases are mild and easily reversible, but it may manifest as severe acute renal injury requiring dialysis. Renal impairment is associated with a large tumor mass and consequently confers a poor prognosis. The prognosis of myeloma has improved with the introduction of novel agents and autologous stem cell transplantation. These improvements appear to apply equally to patients with renal impairment, although the risk of complication is usually higher in this group of patients. In addition to improved overall survival, there is some evidence that novel therapies have improved the renal prognosis. Treatment with high-dose dexamethasone and bortezomib can rapidly reduce light chain production and provide an opportunity for renal recovery. Although trials of plasma exchange (to remove the nephrotoxic light chain) have shown a disappointing lack of benefit, high cutoff dialysis removes larger quantities of light chain; therefore, trials are underway to investigate whether this can improve the renal prognosis independently of chemotherapy. Outcomes in patients with myeloma kidney do appear to be improving, but more trials are needed (some of which are in progress). There is cause for optimism for physicians and for patients suffering from this condition.

Novel therapies in monoclonal gammopathies

Multiple myeloma (MM) is a plasma cell malignancy with an incidence of approximately 20 000 cases per year. Over the past decade, the advent of novel therapies has resulted in a positive shift in survival for patients with advanced MM. Over the last decade progress has been made in the understanding of the mechanisms involved in myeloma cell proliferation, trafficking and survival. Through this understanding, molecular therapeutic targets have been identified and treatment programs which incorporate these concepts are beginning to appear. The current review does not intend to be a comprehensive compendium of available treatments rather to highlight the most exciting avenues of research in myeloma therapeutics. Novel immunomodulating drugs, proteasome inhibitors and monoclonal antibodies will be highlighted.

Novel therapeutic agents for the management of patients with multiple myeloma and renal impairment

Renal impairment is a major complication of multiple myeloma. Patients presenting with severe renal impairment represent a greater therapeutic challenge and generally have poorer outcome. However, once patients with renal impairment achieve remission, their outcomes are comparable with those of patients without renal impairment. Therapies that offer substantial activity in this setting are needed. Bortezomib, thalidomide, and lenalidomide have substantially improved the survival of patients with multiple myeloma. Here we review the pharmacokinetics, activity, and safety of these agents in patients with renal impairment. Bortezomib can be administered at the full approved dose and schedule in renally impaired patients; similarly, no dose reductions are required with thalidomide. The pharmacokinetics of lenalidomide is affected by its renal route of excretion, and dose adjustments are recommended for moderate/severe impairment. Substantial evidence has emerged showing that these novel agents improve outcomes of patients with renal impairment, including impairment reversal. Bortezomib, thalidomide, and lenalidomide (at the recommended doses) are active options for patients with mild to moderate impairment, although limited data are available for thalidomide. Information on lenalidomide-based combinations is still emerging, but the available data indicate considerable activity. Substantial evidence indicates that bortezomib-high-dose dexamethasone with or without a third drug (e.g., cyclophosphamide, thalidomide, or doxorubicin) is an appropriate option for patients with any degree of renal impairment.