PTC Therapeutics Expands Rare Disease Portfolio with Censa Acquisition

PTC Therapeutics has entered into an agreement to acquire Censa Pharmaceuticals, a biotech company developing therapies for orphan metabolic diseases, including phenylketonuria.

Photo: Stuart Peltz, CEO of PTC Therapeutics

Under the terms of their agreement, PTC will pay Censa’s shareholders $10 million cash and about $40 million worth of PTC common stock.

In addition, Censa shareholders are eligible for another $217.5 million in development and regulatory milestones for the two most advanced programs and receipt of a priority review voucher, including $30 million to be paid in either cash or PTC common stock for completing the enrollment of a phase 3 clinical trial for CNSA-001 for PKU, $109 million in development and regulatory milestones for each additional indication of CNSA-001, net sales milestones up to an aggregate amount of $160 million, and a contingent value payment of a percentage of annual net sales ranging from single to low double digits. The transaction is expected to close in the second quarter of 2020.

Phenylketonuria (PKU) is an inborn error of metabolism caused predominantly by mutations in the phenylalanine hydroxylase (PAH) gene that result in toxic buildup of the amino acid phenylalanine in the brain. With the near universal adoption of newborn screening for high plasma phenylalanine, PKU is typically diagnosed at birth. It is estimated that there are 16,500 patients in the United States. If left untreated, severe and irreversible disability can occur including permanent intellectual disability, seizures, delayed development, behavioral problems, and possible psychiatric disorders.

It has been shown that administration of tetrahydrobiopterin improves the function of PAH resulting in reduction in phenylalanine plasma concentration. Censa’s lead therapeutic CNSA-001 is an oral formulation of synthetic sepiapterin, a precursor to intracellular tetrahydrobiopterin, which is a critical enzymatic cofactor involved in the metabolism and synthesis of numerous metabolic products. The phase 2 trial evaluating CNSA-001 for PKU met its primary and secondary endpoints in December 2019, and the program is phase 3 ready. CNSA-001 has also been pursued as a possible treatment for other orphan metabolic diseases associated with defects in the tetrahydrobiopterin biochemical pathways.

“Results from a phase 2 clinical trial of CNSA-001 demonstrated significant and clinically relevant reductions in phenylanaline levels compared to current first-line treatment,” said Stuart Peltz, CEO of PTC Therapeutics.

Author: Rare Daily Staff