Why the MS field might invest in biased opioid agonists
Although the failed Phase II multiple sclerosis trial of Biogen Inc.'s anti-LINGO mAb in June dealt a blow to myelin repair, a slew of compounds acting by different mechanisms lies behind it in clinical and preclinical development. Now, two independent groups have added the kappa opioid receptor (KOR) to the list of targets, showing activation of kappa receptors in mouse models of MS triggers production of oligodendrocytes, the cells that make myelin, boosting myelin repair and recovery of muscle function.
But while the obvious challenge will be avoiding the psychotropic side effects of activating the kappa receptor, the results might be relevant beyond the receptors themselves, shedding a light on the control of myelination to inform other strategies.
With marketed therapies for MS achieving at least some control over the inflammatory immune attacks that demyelinate nerve axons, the field has largely turned its focus to repairing the lost myelin, with the goal of reversing the damage rather than merely halting the decline.
"Promoting natural, endogenous repair mechanisms is a leading strategy for MS," said Bruce Bebo, EVP of research at the National Multiple Sclerosis Society (NMSS), who noted that non-immunological approaches such as this could benefit people with forms of the disease in which inflammation plays a smaller role - in particular the progressive forms of MS.
While Biogen's compound, opicinumab, missed its primary endpoint in the SYNERGY trial of improvement on at least one of four measures - Expanded Disability Status Scale (EDSS), timed 25-foot walk (T25FW), nine-hole peg test (9-HPT) or three-second Paced Auditory Serial Addition Test (PASAT-3) - the company believes the compound still holds promise and is planning additional trials.
In addition, at least ten other companies and two universities have 11 products in development that could boost