Shares of Summit Therapeutics plunged more than 78 percent in premarket trading.
Shares of Summit Therapeutics plunged more than 78 percent in premarket trading after the company announced it will discontinue development of its Duchenne muscular dystrophy treatment ezutromid after the drug failed in a mid-stage clinical trial.
Following 48 weeks of treatment in the open-label Phase II PhaseOut trial, ezutromid, a utrophin modulator, did not meet primary or secondary endpoints. The primary endpoint in the trial of 40 boys with DMD was changed from baseline in magnetic resonance parameters related to the leg muscles. Biopsy measures evaluating utrophin and muscle damage were included as secondary endpoints, with patients having two biopsies: one at baseline and the second after either 24 weeks or 48 weeks of ezutromid treatment. Neither goal was reached in the trial. However, the company said statistical decreases in developmental myosin and magnetic resonance T2 measures were seen after 24 weeks of treatment. That did not hold though through the 48 weeks. Ezutromid was generally well-tolerated in the trial.
DMD is associated with specific errors in the gene that codes for dystrophin, a protein that plays a key structural role in muscle fiber function. Utrophin protein performs a similar role to dystrophin in developing and repairing muscle fibers. As a muscle fiber matures, utrophin is switched off and replaced by dystrophin in the case of healthy individuals. Ezutromid was being developed to maintain utrophin expression in patients with DMD so it can substitute for the lack of dystrophin and break this cycle.
Summit Chief Executive Officer Glyn Edwards said the failure of the Phase II trial was a disappointment for his company, as well as those patients living with DMD>
“While we believe utrophin modulation could still have a place in the treatment of DMD, it is clear that ezutromid is not providing a benefit for patients. We, therefore, feel that our resources are better focused on the development of our promising pipeline of new mechanism antibiotic,” Edwards said in a statement. “We sincerely thank the patients, families and clinical trial sites involved in all of the ezutromid clinical trials for their commitment to advancing research in DMD. We hope that the information we have gathered can ultimately be used to benefit ongoing research in DMD.”
With the failure of the mid-stage trial, Summit said it is discontinuing development of ezutromid. The company also said it will implement cost reduction measures, but did not specify what those will be. It is likely the company could cut some employees as a result. Summit will work with investigators to close out the Phase II PhaseOut trial. The company noted that it intends to take the data from the utrophin modulation pathway and share it with other researchers who are focused on developing treatments for DMD.
One of the most common fatal genetic disorders, DMD affects approximately one in every 3,500 boys born worldwide. The condition is universally fatal, and death usually occurs before the age of 30.
Summit said it will now focus on other pipeline products, including its C. difficile infection treatment ridinilazole, which is expected to enter Phase III testing in the first quarter of 2019.
Summit’s stock closed at $12.65 on Tuesday, but the failure and discontinuation of ezutromid sent investors running. The stock fell to $2.80 in premarket trading.
