PTC Therapeutics down 6% premarket on risdiplam data

PTC Therapeutics (NASDAQ:PTCT) slips 6% premarket on light volume on the heels of one-year data from Part 2 of a Phase 2/3 clinical trial, SUNFISH, conducted by licensee Roche (OTCQX:RHHBY) evaluating risdiplam in patients aged 2 – 25 with nonambulatory type 2 & 3 spinal muscular atrophy (SMA).

The data showed that treatment with risdimplam, an oral mRNA splicing modifier, resulted in a statistically significant improvement in motor function at month 12 from baseline as measured by a scale called MFM-32 compared to placebo.

The company says no new safety signals were observed but there was a range of adverse events that investors may be reacting to: upper respiratory tract infection (31.7%), nasopharyngitis (25.8%), pyrexia (20.8%), headache (20%), diarrhea (16.7%), vomiting (14.2%) and cough (14.2%). The rates of lower respiratory tract infections were similar between risdiplam (19%) and placebo (20%), the rate of serious lower respiratory tract infections was higher in the treatment group (10%) versus the control arm (2%), although deemed unrelated to risdiplam.

By comparison, the most common adverse events in studies of Biogen’s (NASDAQ:BIIB) Spinraza were lower respiratory tract infection (43%), upper respiratory tract infection (39%), constipation (30%), teething (14%) and upper respiratory tract congestion (6%).

Roche’s U.S. marketing application is currently under FDA review with an action date of May 24 (Priority Review status).

https://seekingalpha.com/news/3539181-ptc-therapeutics-down-6-premarket-on-risdiplam-data