A significant majority of multiple sclerosis (MS) patients in the US are not being prescribed immunomodulatory agents (IMAs) such as Betaseron (interferon-1b), Avonex (interferon-1a) and Copaxone (glatiramer acetate), despite indications that the drugs are both effective and cost-effective, a new analysis has found.

Researcher Jagannadha Avasarala, from Kansas Neurological Consultants, and colleagues from Wake Forest University School of Medicine and Ohio State University Medical Center used National Ambulatory Medical Care Survey (NAMCS) data to examine prescribing patterns for IMAs in MS patients between 1998 and 2004. The results were published in the online journal BMC Medicine.

As the researchers pointed out, multiple sclerosis is the second most common cause of neurological disability in young adults after trauma. The natural history of the disease suggests that disability accumulates over time and IMAs can reduce the frequency of new enhancing lesions, relapses and the rate of cerebral atrophy, they noted, adding that the launch of Betaseron, Avonex and Copaxone, with efficacy demonstrated in three large placebo-controlled, double-blind studies, “represents a major breakthrough in MS therapy”.

There are also indications from economic modelling that IMAs are cost-effective. “Although the costs of treatment remain high”, the authors commented, “loss of productivity and direct care costs for individuals disabled by MS are higher with worsening expanded disability status scores (EDSS).”

In all, six IMAs have been approved by the US Food and Drug Administration since the early 1990s for the treatment of MS: the three drugs already mentioned, plus Rebif (interferon-1a), Novantrone (mitoxantrone) and Tysabri (natalizumab). The last of these was withdrawn from the market in February 2005 following an association with progressive multifocal leukoencephalopathy (PML), a rare and potentially fatal viral infection of the brain. It has since returned, but at the cost of some prescribing restrictions.

The NAMCS data tracked outpatient visits to office-based physicians. The analysis in BMC Medicine focused on what these data revealed about the use of imunnomodulators in established MS patients, as “initial visits to physicians could be part of a diagnostic work-up and IMA use may not be initiated during the first visit”. There were an estimated 6.7 million visits to outpatient clinics by people with MS between 1998 and 2004, with neurologists recording 50.7% of these visits and general/family practices and internists combined accounting for 33.7%.

The researchers found that 62% of established MS patients seeing neurologists and 92% of those seeing family medicine practitioners or internists were not being treated with IMAs. The more liberal use of immunomodulators by neurologists “probably reflects greater awareness of the drugs’ availability and their use by specialists who more often treat patients with MS”, the authors said. There was no statistical evidence of a decline or increase in IMA use over the study period.

Outpatient management of multiple sclerosis in the US “remains far from ideal”, the researchers concluded. A possible means of improving prescribing trends, they suggested, would be to pinpoint variations in service delivery and embark on longitudinal follow-up studies. “Above all, strategies for educating both neurologists and non-neurologists about the benefits of initiating IMA use in MS patients and in continuing their use remain critical to improving long-term patient outcomes in the treatment of MS,” they stated.