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Restricted Drug Coverage Tied to Higher Risk for MS Relapse
Restricted coverage of medications for relapsing-remitting multiple sclerosis (MS) was associated with a higher risk for relapse, a new study showed.
Patients with MS enrolled in Medicare Advantage Prescription Drug plans (MA-PDs) with broader formulary coverage were 8%-12% less likely to experience an MS relapse, while those in broad-coverage stand-alone prescription drug plans (PDPs) had 6%-9% lower odds of relapse.
The findings highlight that cost-saving measures used by pharmacy benefit managers to exclude certain drugs from formularies can have tangible negative outcomes, especially for patients with complex or chronic conditions.
'Patients with MS may need to try multiple drugs to find what works best for them. Broad formulary exclusions ultimately undermine the individualized care these patients need,' said lead author Geoffrey Joyce, PhD, director of Health Policy at the Schaeffer Center and chair in the Department of Pharmaceutical and Health Economics at the University of Southern California in Los Angeles, in a news release.
The study was published online on August 1 in JAMA Network Open .
Cost-Cutting May Come at Patients' Expense
Part of the push to exclude certain medications or seek rebates is due to the increasing number of therapies within the same class, the investigators noted.
Competition among manufacturers allows pharmacy benefit managers to negotiate better prices via the exclusion of more costly drugs from their formulary. This can prevent some patients from getting their prescribed medication, such as drugs for relapsing-remitting MS, which are not protected by Medicare's Part D classifications.
A 2024 study showed that Medicare Part D plan formularies excluded an average 44.7% of brand-only compounds and that drug restrictions for this plan increased over the study period of 2011-2020.
To investigate whether such exclusions were associated with relapse episodes for MS patients, the researchers analyzed Medicare data of 50,162 beneficiaries in PDPs (mean age, 58.5 years; 74.9% women; 80.7% White) and 34,708 in MA-PDs (mean age, 58.2 years; 77.2% women; 75.5% White).
More MS Therapies, Less Coverage
The study timeline was divided into quarters, starting in 2019 (2020 Q2 was left out as a result of COVID-19 disruptions). To gauge patient outcomes, the first four quarters were used as a baseline period and the fifth quarter as the follow-up period.
Beneficiary severity of MS was evaluated using the expanded disability status scale derived from the disability/impairment scores. The researchers looked at 15 disease-modifying therapies (DMTs) on the market from 2018 to 2022. In their analysis, the Medicare plans were assumed to cover the five intravenous MS DMTs.
The amount of on-formulary MS DMTs was calculated to give a four-quarter moving average and DMTs were classified as on formulary if their generic name was covered by the plans.
Plans were deemed low coverage if the four-quarter moving average of DMTs was below the plan's median during baseline. For the follow-up portion, logistic regression models were employed for MS relapse episodes, and Poisson or negative binomial regression models were used for nonbinary dependent variables such as the number of relapse episodes. Multivariable regression models were used to control for patient characteristics.
PDPs typically covered only four of the 15 drugs across four classes, while MA-PDs covered double this across five classes.
Many oral and injectable DMTs were frequently not covered by plans particularly in stand-alone plans, such as teriflunomide (amount of plans without compound on formulary: PDP, 87.7%; MA-DP, 43.3%), ofatumumab (PDP, 99.6%; MA-DP, 86%), and interferon beta-1a (PDP, 86.5%; MA-DP, 41.4%).
The rate of any MS relapse was higher for low-coverage plans compared with broader coverage plans for PDPs (10.6% vs 9.5%; odds ratio [OR], 0.88 [95% CI, 0.85-0.91]) and MA-PDs (7.8% vs 6.9%; OR, 0.88 [95% CI, 0.84-0.92]).
MS is most commonly diagnosed between 20 and 40 years of age — a limitation of the study was that most Medicare beneficiaries are older than this cohort. Other limitations were potential administration errors inherent in health claims data and that quarterly periods might not be sufficient to fully evaluate the relationship between formulary coverage and relapse episodes.
The researchers noted that the effect of such restrictions might be exacerbated for Part D beneficiaries, thanks to the new $2000 annual cap on out-of-pocket drug expenses.
'Innovative new treatments have made it possible to slow or prevent symptoms for some of the most complex diseases, but costs remain a challenge,' Joyce said. 'We must find sustainable ways to ensure all patients can access these potentially life-changing treatments.'
