Practical management of adverse events in multiple myeloma: can therapy be attenuated in older patients?

The current standard of care for elderly patients with newly diagnosed multiple myeloma is melphalan and prednisone (MP) in combination with either bortezomib (VMP) or thalidomide (MPT), with lenalidomide plus dexamethasone increasingly being employed. The addition of bortezomib or thalidomide to the established MP regimen significantly improves outcomes and prolongs survival in elderly and transplant-ineligible patients. However, these benefits are accompanied by increases in treatment-related adverse events (AEs), which may be particularly pronounced in older individuals. Patients receiving bortezomib as part of a VMP regimen commonly experience transient and cyclical thrombocytopenia and neutropenia, along with gastrointestinal AEs. Fortunately, these AEs can be managed with appropriate supportive care and, when necessary, adjustments in dose. Peripheral neuropathy (PN) is the most important side effect of bortezomib, and although it is reversible in a high proportion of patients, it affects their quality of life. Furthermore, PN can require temporary or permanent withholding of bortezomib, which will reduce treatment efficacy. PN is also a common adverse effect of thalidomide; thromboembolic events are also a key concern, requiring thromboprophylaxis in patients receiving thalidomide in combination. For lenalidomide in combination with dexamethasone, the most clinically important adverse effects are hematologic toxicity (particularly neutropenia) and thromboembolic events. Recent phase III studies in newly diagnosed elderly patients are providing further insight into the most appropriate treatment regimens to maximize outcomes and minimize toxicity in individual patients. Of note, once-weekly bortezomib dosing (in combination with MP±T) was shown to reduce the incidence of peripheral neuropathy and gastrointestinal events compared with twice-weekly dosing, while maintaining efficacy. Elderly patients may be less able to withstand the AEs associated with newer treatment regimens and combinations of multiple drugs, and may experience greater declines in quality of life and, subsequently, reduced treatment adherence. It is therefore critical that these patients are closely monitored and any emergent AEs promptly and appropriately managed. For very elderly, frail patients, tailored therapy, reduced intensity regimens, and adverse event management are necessary to encourage treatment adherence and reduce discontinuation. This article will provide practical guidance on the management of bortezomib-, thalidomide-, and lenalidomide-associated AEs, to maximize treatment feasibility and active drug delivered, and thus help minimize toxicity and maximize outcomes.