Glatiramer acetate significantly delayed the conversion of clinically isolated syndrome to clinically definite multiple sclerosis, according to a randomized, double-blind, placebo-controlled trial published in the Lancet.
The drug reduced the risk of developing clinically definite multiple sclerosis (MS) by 45% compared with placebo, wrote Dr. Giancarlo Comi of the University Vita-Salute, Milan, and his coinvestigators from the PreCISe study (Lancet 2009[doi:10.1016/S0140-6736(09)61259-9]). In addition, the time it took for 25% of patients to convert to clinically definite disease more than doubled, from 336 days for placebo to 722 days for glatiramer acetate.
Glatiramer acetate previously has been shown to reduce relapses in patients with the relapsing-remitting form of MS.
In 85% of patients who are eventually diagnosed with MS, the first clinical event is an acute episode that goes away on its own. This is known as a clinically isolated syndrome. Not everyone who experiences a clinically isolated syndrome goes on to develop MS. After 15-20 years, about half of these patients will have major locomotor disabilities, but about a third will have little or no disability, Dr. David H. Miller of University College London, and Dr. Siobhan M. Leary of the National Hospital for Neurology and Neurosurgery, London, noted in a commentary (Lancet 2009 [doi:10.1016/S0140-6736(09)61453-7]).
Beta interferon also has been shown in placebo-controlled trials to delay the conversion of the clinically isolated syndrome to clinically definite disease, Dr. Miller and Dr. Leary wrote.
The PreCISe (Presenting With a Clinically Isolated Syndrome) study was funded by Teva Pharmaceutical Industries, which markets glatiramer acetate under the brand name Copaxone. Dr. Comi, along with several of his co-authors, acknowledged relationships with Teva. He served on company advisory boards, he served as a consultant, and he received honoraria for speaking activities. In addition, Dr. Comi disclosed relationships with Novartis, Sanofi-Aventis, Merck-Serono, Biogen-Dompe, and Bayer Schering.
The trial involved 481 patients at 80 sites in 16 countries. They were randomized to receive either 20 mg per day of subcutaneous glatiramer acetate or placebo for up to 36 months.
Patients were 18-45 years old at trial entry. All had a single unifocal neurologic event less than 90 days earlier along with a brain MRI showing at least two cerebral lesions at least 6 mm in diameter. Patients were excluded if they had a multifocal clinical presentation, diseases other than MS responsible for the clinical or MRI presentation, or had used beta interferon, chronic corticosteroids, or any experimental or investigational drugs within 6 months of screening.
The most common adverse events among patients taking glatiramer acetate were injection-site reactions (56% vs. 24% for those taking placebo) and immediate postinjection reactions (19% vs. 5%).
Dr. Miller and Dr. Leary wrote that some neurologists are likely to recommend beta interferon or glatiramer acetate to most patients with a clinically isolated syndrome. Others, however, will choose to take a wait and see approach, reasoning that many of these patients will never progress and that others will remain well for a long time.
Dr. Miller reported that he has received research grants through his institution for companies that manufacture drugs for MS, and has also received honoraria and travel expenses from them. Dr. Leary also reported receiving travel grants for meetings from such companies, including Teva.