FDA Grants Rare Pediatric Disease Designation to Spirovant and Oncoheroes as Expiration Approaches

Rare Daily Staff

The U.S. Food and Drug Administration granted Rare Pediatric Disease designations to gene therapy developer Spirovant Sciences and childhood cancer therapy developer Oncoheroes as the program is set to expire at month end.

The FDA granted Spirovant the designation for SPIRO-2101, a gene therapy for cystic fibrosis.

Cystic fibrosis is a life-threatening, autosomal recessive genetic disease with no cure. It is caused by mutations of the gene encoding the CFTR, a channel that conducts chloride and bicarbonate ions across epithelial cell membranes. Derangement of CFTR interferes with mucociliary transport and antibacterial activity in the airways and gut, which leads to a buildup of mucus and susceptibility to airway infections that is ultimately lethal. Cystic fibrosis is primarily characterized by progressive airway infection and inflammation, and, in most individuals, death from respiratory failure.

SPIRO-2101, an inhaled adeno-associated virus  gene therapy, is designed to replace a defective cystic fibrosis transmembrane conductance regulator (CFTR) gene in patients with class 1 mutations or in those who are unable to tolerate an existing CFTR modulator. SPIRO-2101 contains an evolved AAV capsid engineered to have high tropism to human airway epithelia. The treatment is designed for these patients who currently have no approved modulator therapies.

The agency also granted Rare Pediatric Disease designation to Oncoheroes Biosciences’ experimental therapy volasertib, an investigational treatment for rhabdomyosarcoma, a rare cancer that most often affects children.

Rhabdomyosarcoma forms in soft tissue, particularly skeletal muscle tissue. The five-year survival for children overall is about 70 percent, but the rates vary widely depending on tumor location, stage, and age. Currently, children with the most aggressive subtypes of the disease have a five-year survival rate of about 20 to 30 percent.

Volasertib is an inhibitor of polo-like-kinase 1 (PLK1), an enzyme known to be involved in disease progression in a number of cancers. The compound was originally discovered and developed by Boehringer Ingelheim for the treatment of acute myeloid leukemia until the company decided to discontinue the compound for strategic reasons. In 2019, Oncoheroes in-licensed volasertib from Boehringer Ingelheim to continue the clinical development of this drug candidate for the benefit of younger cancer patients.

The FDA grants Rare Pediatric Disease designation for serious or life-threatening diseases with manifestations in individuals aged from birth to 18 years, including access to the FDA’s expedited review and approval process. The designation makes these drugs eligible for a Rare Pediatric Disease Priority Review voucher upon approval of the therapy by the FDA. There are no approved therapies for these conditions.

The vouchers can be used to reduce the time of an FDA new drug approval review to six months from ten months. The vouchers are potentially lucrative because they are transferable. Most recently, Sarepta sold its priority review voucher to Vifor Pharma $111 million in February 2020.

Though the program is due to expire at the end of the month, a drug that has been granted RPD designation prior to this date is still eligible to receive the voucher if it receives final FDA approval before September 30, 2022. There is also legislation that has been introduced to extend the program.

Editor’s note: This story was updated to correct the most recent sales of a priority review voucher.