Medicare Part D Beneficiaries With Myeloma Receive Novel Therapies More Frequently, Have Better Survival Than Nonenrollees

People with myeloma who have prescription drug coverage under Medicare are less likely to use older cytotoxic chemotherapy and more likely to receive newly approved therapies, compared with patients who are not enrolled in Medicare. Enrollment in a Medicare Part D plan (PDP) or through a supplemental plan also was tied to better survival outcomes, according to a study published in the Journal of Clinical Oncology.

“Our results highlight the increasing need to provide financial guidance and discuss economic repercussions of cancer therapy with patients, particularly those with hematologic malignancies treated with expensive oral antineoplastic agents,” lead author Adam J. Olszewski, MD, of Brown University told ASH Clinical News. “If access to all treatment options at diagnosis is associated with survival outcomes (as we have observed), then we can expect emergence of significant disparities depending on site of care.”

Traditional Medicare plans covered only parenteral chemotherapy, potentially limiting patients’ access to newer, more effective oral therapies like the immunomodulatory drugs (IMiDs) lenalidomide and thalidomide or the proteasome inhibitor ixazomib. In 2006, the Centers for Medicare and Medicaid Services enacted the PDP drug benefit, which allowed beneficiaries to obtain prescription coverage through employer-sponsored plans or federal employee or veterans’ benefits, collectively referred to as other creditable coverage (OCC).

To determine how these drug benefits affected access to therapies, receipt of therapy, and survival among Medicare beneficiaries, the researchers obtained patient data from 9,755 Medicare enrollees who were diagnosed with myeloma between 2006 and 2011. All patients were enrolled in a Medicare Part A/B plan before diagnosis for at least a year prior to diagnosis.

Coverage status at diagnosis was as follows:

  • No prescription drug coverage (n=1,460; 15%)
  • PDP coverage without Medicaid (n=3,823; 34%)
  • OCC (n=3,607; 37%)
  • Medicare/Medicaid dual enrollment (n=1,405; 14%)

Beneficiaries actively changed their prescription coverage status after myeloma diagnosis; for example, 41 percent of those without coverage at diagnosis obtained either PDP or OCC by the following January. However, PDP enrollees at diagnosis universally maintained their coverage.

Baseline characteristics were similar between patients who did or did not switch coverage, except that people who obtained PDP or OCC were more likely to have no recorded comorbidities (64% vs. 54%; p=0.001) and to undergo a hematopoietic cell transplantation (11% vs. 7%; p=0.015).

The overall proportion of beneficiaries who received active antimyeloma care increased slightly during the study period, from 88 percent in 2006 to 91 percent in 2011. The proportion who received any parenteral chemotherapy also increased, doubling from 24 to 48 percent, “mainly as a result of the expanding use of bortezomib,” the authors noted.

In the group of PDP enrollees, bortezomib use increased from 13 to 44 percent during the study period, but the proportion of patients who received IMiDs remained “fairly steady” at 31 percent.

The researchers observed that treatment of myeloma differed substantially by patients’ type of prescription drug coverage (TABLE 1).

Compared with beneficiaries without coverage, PDP enrollees were:

  • 6% more likely to receive active care for myeloma
  • 14% less likely to receive parenteral chemotherapy
  • 38% less likely to receive classic cytotoxic agents

(P values were not reported for these comparisons.)

However, there were no significant differences in bortezomib use – likely because bortezomib was already covered under the drug benefits of traditional Medicare plans.

OCC recipients were 3 percent more likely to receive active antimyeloma therapy, compared with beneficiaries without coverage, but again, the use of parenteral regimens did not differ significantly (p values not reported).

After a median follow-up of 4.9 years (range not reported), 70 percent of patients in the study died. Median survival was 2.3 years (range = 2.2-2.4 years) and the three-year rate of overall survival (OS) was 43.1 percent (TABLE 2).

While there were no differences in survival between the OCC and PDP groups, patients with OCC and PDP coverage had significantly longer survival, compared with those without coverage:

  • PDP: adjusted restricted mean survival time (RMST) ratio = 1.16 (95% CI 1.11-1.20; p value not reported)
  • OCC: adjusted RMST ratio = 1.16 (95% CI 1.12-1.21; p value not reported)

The researchers reported that Medicaid dual enrollees had notably worse OS, which is consistent with their burden of comorbidities and poor performance status, but, after adjustment for these unfavorable baseline characteristics, Medicaid dual enrollees actually had better OS than those without coverage (adjusted RMST ratio = 1.08; 95% CI 1.03-1.13; p value not reported).

Although patients with Medicare PDP or OCC coverage appeared to have better survival outcomes, “we could not discern whether worse survival in the group without coverage was a result of not receiving therapy at all, an inability to access immunomodulatory drugs, or poor control of other medical issues,” the authors concluded. “As most patients with myeloma in the United States are covered by Medicare, our results have important implications both for the clinicians who care for these patients and for health-care policy that tackles coverage of oral and parenteral anticancer therapy.”

The authors noted that this analysis was limited by its reliance on retrospective data. This introduced the potential for “unobserved clinical differences between beneficiaries with and without prescription drug coverage,” which may have contributed to differences in mortality outcomes.

Also, the comparison of treatments was restricted to parenteral regimens, because oral IMiDs covered by PDP plans were tracked, but nonbeneficiaries who obtained oral agents through non-PDP insurance plans would not have been recorded in the Medicare database. “The inability to [comprehensively] identify oral chemotherapy [use] is a major hurdle for health services research using Medicare data – a problem of increasing importance … [considering that] IMiDs are covered by more than 93 percent of Medicare prescription plans,” they added. The study exclusion criteria also means that these findings cannot be extrapolated to Medicare managed-care plan enrollees or to younger patients.

“Our finding of an association between prescription coverage at diagnosis and survival in myeloma will need to be evaluated in other settings where oral anticancer therapies can provide substantial clinical advantage,” Dr. Olszewski said. “As health-services researchers, we are looking forward to ongoing initiatives that could enrich the data in ways that will make the analyses more impactful for the clinical practice.”

The study authors reported financial relationships with Spectrum Pharmaceuticals, Genentech, TG Therapeutics, Celgene, Kyowa Kirin, Jazz Pharmaceuticals, Tolero Pharmaceuticals, Boehringer Ingelheim, and the PhRMA Foundation.


Reference

Olszewski AJ, Dusetzina SB, Trivedi AN, Davidoff AJ. Prescription drug coverage and outcomes of myeloma therapy among Medicare beneficiaries. J Clin Oncol. 2018;36:2879-86.

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