Sarepta Therapeutics Inc (NASDAQ:SRPT) has started dosing patients in the phase III trial of two new treatments for Duchenne muscular dystrophy (DMD).
DMD is a fatal muscle wasting disease that affects boys and young men up to the age of 30.
It is caused by faults in the gene that encodes dystrophin, a protein that is essential for the healthy function of all muscles.
The US biotech recently received US approval for DMD treatment Exondys 51 or eteplirsen, a weekly intravenous injection for sufferers of one of the types of genetic mutation that cause the disease.
Eyebrows were raised when the company said the new drug would cost US$300,000 a year per prescription.
Analysts said that would make it a US$1bn per year earner even though DMD affects relatively few people.
The phase III trial now underway will study the efficacy of SRP-4045 and SRP-4053 in DMD patients amenable to exon 45 or 53 skipping as opposed to exon 51 skipping, which Exondys 51 addresses. Exon refers to the DNA sequence within a gene.
Approximately 99 patients aged 7 to 13 years inclusive will be enrolled with a minimum target of 45 patients. The trial will take up to 96 weeks.