No Resolution of CNS Lesions
Even after 48 weeks, none of the lesions had resolved, according to Maria I. Gaitán, MD, acting director of the Translational Neuroradiology Unit of the National Institute of Neurological Disorders and Stroke (NINDS), Bethesda, Maryland.
Again, although these findings were disappointing, Dr. Gaitán said there are a number of explanations for the result that do not preclude a benefit from BTK inhibitors in future studies.
“Complete resolution of PRL might be a bar that was too high,” she said, noting that favorable changes in these lesions could have occurred even if the characteristic iron deposits persisted. She also suggested that dosing might not have been optimized to halt or reverse disease activity in the CNS. Like Dr. Montalban, she suggested that BTK inhibitors with different characteristics might succeed where tolebrutinib failed.
Dr. Freedman, current president of ACTRIMS, agreed that these data should not be interpreted as ruling out a clinical role for BTK inhibitors. Pointing to the substantial body of data supporting this mechanism for reversing inflammation in the CNS, he declared that “the story is not over.”
Dr. Montalban reported financial relationships with Actelion, Alexion, Bayer, Biogen, Bristol-Myers Squibb, Celgene, EMD Serono, Hoffman La Roche, Immunic, Janssen, Mylan, NervGen, Novartis, Sanofi-Genzyme, Teva, TG Therapeutics, and Merck, which provided funding for the RMS 1 and 2 trials. Dr. Freedman reported financial relationships with Actelion, Alexion, Bayer, Biogen, Celgene, EMD Serono, Hoffman La Roche, Merck, Novartis, and Teva Canada Innovation. Dr. Gaitán reported no potential conflicts of interest.