ProQR Therapeutics hoped additional analyses of a failed clinical test of its lead RNA therapy would salvage the experimental eye disease drug, but European regulators told the biotech it needs to run another clinical trial. Rather than conduct that study, ProQR plans to stop ophthalmology research and focus instead on other applications of its RNA-editing technology.
Further development of sepofarsen and ultevursen, ProQR’s two most advanced eye drug candidates, will depend on another company. Leiden, Netherlands-based ProQR said Thursday that it is looking for a strategic partner for all of its ophthalmology assets. By winding down clinical trial work for its two most advanced RNA drug candidates, ProQR estimates it will save enough cash to support the company into 2026.
Sepofarsen had reached pivotal testing in Leber congenital amaurosis 10, an inherited eye disorder characterized by the degeneration or dysfunction of the photoreceptors of the retina. Injected into the eye, the RNA therapy was intended to repair the genetic mutation at the root of the disease.
Earlier this year, ProQR reported that sepofarsen had failed a Phase 2/3 study, posting results in the treatment group that showed no difference compared to a control group given a sham procedure. But the company saw a glimmer of light in its analysis of data conducted after the study was done. ProQR said that when the treated eye was compared to the untreated eye in the same patient, a benefit in vision was observed at month 12. That effect was not observed in those given a sham injection.
The results from the additional analysis were not enough to persuade the European Medicines Agency, but ProQR CEO Daniel de Boer said in a prepared statement that the agency’s regulatory feedback is helpful in designing an additional clinical trial that could support a marketing authorization application. That information would be useful to any company looking to acquire or partner on sepofarsen or the other ProQR ophthalmology assets. The ultevursen program was enrolling patients in a pivotal Phase 2/3 study in Usher syndrome, a rare inherited disorder that leads to vision and hearing loss, and retinitis pigmentosa, which is another degenerative retinal disorder. That RNA therapy posted encouraging results in Phase 1/2 testing last year.
A Deep-dive Into Specialty Pharma
A specialty drug is a class of prescription medications used to treat complex, chronic or rare medical conditions. Although this classification was originally intended to define the treatment of rare, also termed “orphan” diseases, affecting fewer than 200,000 people in the US, more recently, specialty drugs have emerged as the cornerstone of treatment for chronic and complex diseases such as cancer, autoimmune conditions, diabetes, hepatitis C, and HIV/AIDS.
Going forward, ProQR will focus on Axiomer, its RNA-editing technology platform. The initial therapeutic areas will include the liver and the central nervous system (CNS). ProQR said both areas align with the company’s approach of delivering oligonucleotides, which are short strands of synthetic RNA. Liver and CNS are also areas of focus for an Axiomer-based research partnership with Eli Lilly. That deal paid ProQR $50 million up front and could bring up to $1.25 billion more depending on the progress of the research. ProQR said that it may enter additional partnerships with the platform.
As ProQR proceeds with its strategy shift, the company expects to announce new pipeline targets late this year or early next, according to an investor presentation. The company also expects to be able to provide progress updates for its partnership with Eli Lilly. In its report of second quarter 2022 financial results last week, ProQR said it had €156.4 million in cash and cash equivalents as of June 30.
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