On Monday, I reported on an innovative, new acne bacteria-derived treatment for Secondary Progressive Multiple Sclerosis (SPMS) currently under development in Australia. Treatments such as these give new hope to patients with SPMS because very few of the approved, available therapies are reported to be beneficial, as the drugs (usually interferon- and disease-modifying drugs) are targeted towards patients with relapsing-remitting MS. A new, promising treatment, which is being specifically tested for secondary progressive MS, may be added to the mix in the near future.
The drug, natalizumab (Tysabri), from Biogen Idec is currently in Phase 3b Clinical Trials. Officially titled “A Multicenter, Randomized, Double-Blind, Placebo-Controlled Study of the Efficacy of Natalizumab on Reducing Disability Progression in Subjects With Secondary Progressive Multiple Sclerosis, With Optional Open-Label Extension,” the trial is split into two parts. Part 1 is investigating if natalizumab slows the accumulation of disability not related to relapses relative to a placebo, and Part 2 is a continuation of the safety evaluation of natalizumab, where all participants may receive natalizumab. The trial began in July 2011 and is estimated to be completed in December 2014, with longer-term endpoints being collected for a total of approximately four years.
Two groups of patients between the ages of 18 and 58 years are being evaluated in parallel: one group is receiving 300 mg of natalizumab intravenously every four weeks, and the other is receiving a placebo intravenously every four weeks. Neither the patients nor the evaluators are aware of who is in which group, making it a double-blind placebo-controlled trial. Primary endpoints will be determined through a series of tests, including a timed 25-foot walk and a questionnaire of work productivity and activity impairment.
Positive results from earlier-stage Secondary Progressive MS natalizumab trials are attributed to the anti-inflammatory properties of natalizumab. Continual inflammation surrounding neurons scarred by autoimmune attacks worsens disability in patients with SPMS, and the proposed benefit of natalizumab is a reduction in the number of attacks by immune cells on neurons. Natalizumab is similar to another drug, vedolizumab, which is under development by Takeda Pharmaceuticals for the treatment of ulcerative colitis, and was covered in the news last week on BioNews Texas. Both attenuate inflammation-promoting effects of the immune system.