Isis Reports Data From ISIS-SMN Rx Phase2 Studies In Infants & Children With SMA

(RTTNews) - Isis Pharmaceuticals Inc. (ISIS) provided an update on its ongoing open-label Phase 2 clinical studies of ISIS-SMNRx in infants and children with spinal muscular atrophy or SMA at the 19th International World Muscle Society or WMS Congress in Berlin, Germany.

Isis said it is currently treating infants with SMA with ISIS-SMNRx in a Phase 3 study called ENDEAR, and plans to initiate a second Phase 3 study, called CHERISH, in children with SMA later this year.

Richard Finkel, M.D., chief, division of neurology, department of pediatrics, Nemours Children's Hospital said that he is encouraged with the totality of the data presented today, which show that median event-free ages for SMA infants in both the 6 mg and 12 mg cohorts compare favorably to that observed in a recent natural history study. These data combined with the safety and tolerability profile observed to date support my enthusiasm to further evaluate ISIS-SMNRx in a Phase 3 study in infants with Type I SMA.

Richard Finkel also said that often infants with Type I SMA succumb to early death due to progressive weakness of the muscles responsible for breathing and feeding. In the PNCR natural history study, for which he was the lead investigator, in a group of untreated patients similar to those in the Isis Phase 2 study, the median event-free age was 10.5 months, with less than 20% of patients event free at 18 months.

In addition to the positive data on event-free survival, substantial and persistent increases in muscle function as measured by the CHOP INTEND and Hammersmith Infant Neurological Examination were also observed in ISIS-SMNRx-treated infants up to 9 months on study. This is an important finding because in general, infants with Type I SMA decline over time in their motor function as reflected in scores on these tests.

Today, Isis reported the results from an analysis of spinal cord tissue samples from autopsies showing that ISIS-SMNRx is distributed throughout the central nervous system. The results of these analyses also showed greater levels of full length SMN2 mRNA and full length SMN protein in tissues in ISIS-SMNRx-treated SMA infants compared to the levels of SMN2 mRNA and full length SMN protein in the tissues analyzed from untreated SMA infants.