Dive Brief:
- Shares in rare disease company Ultragenyx dropped by nearly a fifth Friday on news the biotech's experimental drug UX007 missed its primary and secondary endpoints in a study of patients with glucose transporter type-1 deficiency syndrome (Glut1 DS) who have disabling movement disorders.
- As a result, Ultragenyx is halting its work with UX007 in Glut1 DS. Testing of the candidate in long-chain fatty oxidation disorders (LC-FAOD) will continue, however.
- Ultragenyx plans to submit a New Drug Application for UX007 for the treatment of LC-FAOD and will meet with the FDA before the end of 2018 to discuss its plans. The company also expects to meet with the European Medicines Agency this year.
Dive Insight:
UX007's miss in Glut1 DS appeared to take the company — and its investors — by surprise.
"We had previously observed significant improvements in individual cases of Glut1 DS with UX007 and so we are particularly disappointed by the results of the Glut1 DS study in a larger group of patients that did not demonstrate this same effect," said company CEO Emil Kakkis in an Oct. 26 statement.
But UX007, also known as triheptanoin, has run into clinical hurdles in Glut1 DS before. In March 2017, the drug did not meet its primary endpoint in an earlier study, sending shares down by over 7% then.
That outcome has now been repeated in Phase 3, as UX007 failed to significantly reduce the frequency of paroxysmal movement events compared to placebo.
Analysts met the trial failure with what amounted to a shrug, shifting focus to the opportunity in LC-FAOD.
"Triheptanoin seems likely to obtain FDA approval in another indication — long chain fatty acid oxidation disorder (LC-FAOD) — which together with other progress at the company suggests to us downside for [Ultragenyx] is limited at current levels," wrote Leerink's Joseph Schwartz in a note to investors.
Laura Chico of Raymond James appeared slightly more concerned over the forthcoming regulatory interactions regarding UX007 in LC-FAOD. Still, the analyst expects Ultragenyx to recover from Friday's blow if the rest of its pipeline advances as expected.
While Ultragenyx has secured approvals for Mepsevii (vestronidase alfa) and Crysvita (burosumab-twza), its pipeline has taken hits, too. Last year, Ultragenyx shelved another rare disease development program after Phase 3 results showed its Ace-ER candidate didn't significantly improve arm strength in patients with GNE myopathy.