Biogen Idec and Abbott Laboratories have reported promising results in a Phase IIb trial of daclizumab, their once-monthly injectable treatment for multiple sclerosis.
Top-line results from the dose-ranging SELECT trial in patients with the relapsing-remitting form of MS indicate that treatment with daclizumab at a dose of 150mg given by subcutaneous injection once every four weeks reduced annualised relapse rates by 54% compared to placebo. Disability progression was reduced by 57%.
Pushing the dose up to 300mg provided no additional benefit, with relapse rates down 50% and disability progression down 43% compared to the control group.
The company also said daclizumab met key secondary endpoints in both treatment arms, including a statistically significant reduction in the cumulative number of new gadolinium-enhancing lesions between weeks eight and 24 of the study, while there was a trend towards improvement in quality of life measures at one year.
Analysts raised some questions about side effects seen with daclizumab, however, particularly rises in liver enzymes, infections and skin problems, according to a Wall Street Journal report.
Biogen Idec's executive vice president for R&D, Doug Williams, said the positive SELECT results and previous clinical data support continued investigation the drug in MS. "We hope to confirm the results of SELECT in our second registrational trial, DECIDE," said Williams. Results from that trial are expected in 2013.
Daclizumab is a humanised monoclonal antibody that binds to CD25, an immune cell receptor subunit that is thought to become abnormally activated in MS. It is already approved to prevent kidney transplant rejection under the trade name Zenapax.
Biogen Idec is looking to daclizumab as a more convenient addition to its existing MS franchise, headed by Avonex (interferon beta-1a), which is given by intramuscular injection once a week, and Tysabri (natalizumab), given once a month by intravenous infusion. The two products added $1.22 billion and $438 million respectively to Biogen Idec's coffers in the first half of this year.
Analysts have suggested daclizumab could add another $500 million to the pot per year at peak, although its potential is hard to gauge, given that a number of orally-active MS treatments are on or nearing the market, notably Novartis' Gilenya (fingolimod), Actelion's ponesimod and Teva/Active Biotech's laquinimod.
For its part, Abbott acquired its interest in daclizumab when it bought Facet Biotech in a $722 million deal last year, and is splitting development costs and potential profits with Biogen Idec.