Avidity Biosciences announces results from Phase 1/2 FORTITUDE program

Avidity Biosciences (RNA) announced positive topline data from the dose escalation cohorts of the delpacibart braxlosiran Phase 1/2 FORTITUDE program in Facioscapulohumeral Muscular Dystrophy, FSHD. These data as well as research supporting KHDC1L as a novel DUX4 regulated circulating biomarker will be presented in oral and poster presentations at the 32nd Annual FSHD Society International Research Congress, IRC, being held June 12-13, 2025, in Amsterdam, the Netherlands. Topline data from these cohorts for del-brax treated participants, compared to placebo, demonstrated: Consistent improvement of functional mobility and muscle strength as measured by 10-Meter Walk-Run test, Timed Up and Go and quantitative muscle testing as compared to placebo; Consistent improvement in multiple measures of quality of life as measured by patient reported outcomes and compared to placebo; Rapid and significant reductions in levels of KHDC1L and creatine kinase, a biomarker of muscle damage; and Favorable long-term safety and tolerability with most adverse events mild or moderate, with no related serious or severe adverse events and no discontinuations.