A significant improvement in OS has been established using maintenance lenalidomide following high-dose chemotherapy and stem cell transplantation.4 Only 5% of this study population received stem cell transplantation. This may be due to a median age of 77 years at diagnosis in the group studied, higher than the 66 to 70 years previously published.5 Stem cell transplantation is now commonly being used even in the older population. The 3-year survival of 83% following stem cell transplantation in myeloma patients aged 75 to 84 years was nearly identical to that of the younger population.6 Since stem cell transplantation is feasible in older Medicare beneficiaries and maintenance lenalidomide for 2 years following transplant improves survival, the option of providing maintenance therapy with oral lenalidomide must be made available to Medicare beneficiaries. Due to a very limited use of transplantation in this study, the impact of oral lenalidomide maintenance in OS cannot be judged.
Of the patients reviewed in this study, 6% had a listed diagnosis of plasmacytoma. These individuals typically are treated with radiation therapy only. It is unclear if these patients also received any systemic myeloma therapy or if they ever progressed to myeloma. Availability of prescription drug coverage may not be relevant to this group. Also, the authors reported that part D participants were less likely to receive classic cytotoxic chemotherapy. This may be somewhat irrelevant in Medicare beneficiaries with a median age of 77 years for current practice, as frontline induction with old classic cytotoxic chemotherapy is less commonly used in this population.
Investigators have appropriately recognized a lack of ability to discern whether inferior survival in the group without prescription drug coverage was the result of not receiving therapy at all or inability to receive oral immunomodulatory drugs. There would have been little reason for not proceeding to parenteral therapy. As noted, 41% of beneficiaries without coverage at diagnosis subsequently obtained coverage but continued to have significantly worse survival. Cause of death, including whether related to myeloma, was not reported. The authors suggest that early separation of survival curves could therefore be reflective of suboptimal first-line therapy that lacked oral immunomodulatory drugs. During the study period 2006-2011, first-line use of lenalidomide was common.
Median survival of patients with myeloma in this study was only 27 months. According to the American Cancer Society, in 2018 median survival for stage I myeloma has not been reached, stage II myeloma is 83 months, and stage III myeloma is 43 months. A robust and dynamic landscape in myeloma therapy prevents a clear attribution to individual agents, whether oral or parenteral, in improving OS. Thus, 3-year RMST, while appropriate for 2006-2011, may not be relevant today.
Applications for Clinical Practice
The oncology community routinely encounters difficulty in initiating therapy using oral agents rapidly after diagnosis of myeloma. The retrospective data analyzed in the current study suggests that delay in initiating or unavailability of oral agents may adversely impact OS. The common approach of initiating parenteral therapy while awaiting approvals from payers or charity programs and subsequently adding oral therapy when available has not been studied in assessing OS. The oncology community should initiate plans to obtain prescription drug coverage through either Medicare part D, Medicaid, a sponsored plan, or financial assistance charity programs as soon as possible after diagnosis of myeloma. Moreover, continuation of these prescription drug plans should be strongly considered throughout the course of myeloma, as subsequent lines of treatment will quite likely involve other active and approved oral agents, such as pomalidomide, ixazomib, and panobinostat, besides other supportive therapy.