Potential Gene Therapy for Dystrophic EB, KB103, Named an Orphan Drug by FDA

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by Ana Belo |

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A potential gene therapy for dystrophic epidermolysis bullosa (DEB), KB103 by Krystal Biotech, has been designed an Orphan Drug by the U.S. Food & Drug Administration (FDA) to help it move along in preclinical testing.

KB103 is the company’s lead candidate, and is intended to treat both DEB and recessive DEB (RDEB), this disorder’s most severe form.   

The therapy is based on a virus system, one that cannot replicate or integrate into human DNA, similar to a flu vaccine. The virus acts as a vector to deliver functional human COL7A1 genes directly to the patients’ skin cells. Epidermolysis bullosa is caused by a lack of collagen in the skin, due mutations in the gene coding for type VII collagen, COL7.

It is intended as an off-the-shelf gene therapy for this rare and debilitating skin disease, meaning that — unlike a number of other gene therapies now being investigated — it is not created from the patient’s own tissues and thus individualized. The company believes this will both speed treatment and lower treatment costs should KB103 succeed in trial and be approved, it reports on its website.

“Receiving orphan drug designation is an important step forward in our efforts to bring hope to DEB patients and their families,” Suma M. Krishnan, founder and COO of Krystal Biotech, said in a press release.

The company plans to take initial steps toward a first clinical trial of KB103, announcing that it intends to file an investigative new drug (IND) application with the FDA in early 2018.  

An Orphan Drug designation, granted to investigative treatments of diseases deemed rare —  affecting less than 200,000 people in the U.S. — gives Krystal incentives to proceed with development, including a seven-year period of  U.S. marketing exclusivity should it be approved, and tax credits applied to specific clinical research costs.

Krystal recently received a $700,000 as an equity-based award from the Epidermolysis Bullosa Research Partnership (EBRP) and the Epidermolysis Bullosa Medical Research Foundation (EBMRF) to advance its gene therapy as a potential DEB treatment.  

Pharmacology data from preclinical studies using DEB animal models have yielded encouraging results and will also be used to support the IND request, Krishnan said.

KB103 was also designed a “rare pediatric disease” potential treatment in December 2016, making it eligible for possible priority review  by the FDA should it advance to that point.