Pfizer buys dwarfism drug company Therachon for $810m

Pfizer is spending $340m to acquire Therachon, a European biotech with a drug in trials for achondroplasia, a form of short-limbed dwarfism.

The deal also includes up to $470m in milestone payments related to the development of the drug, called TA-46, which is a soluble fibroblast growth factor receptor 3 (FGFR3) ligand trap that acts as a decoy to dampen down signals that suppress bone growth in people with achondroplasia.

There are currently no approved treatments for achondroplasia, which affects an estimated 250,000 people worldwide, according to Pfizer. TA-46, which has already completed a phase 1 trial, and is being developed as a once-weekly subcutaneous injection for children and adolescents with the disorder.

Therachon has another asset in development, a GLP-2 analogue called apraglutide that is in phase 2 development for short bowel syndrome, but Pfizer says it intends to spin that programme into a separate, independent company backed by its Pfizer Ventures investment group. The biotech acquired apraglutide when it bought GLyPharma last October.

Basel-based Therachon, which was formed in 2014, raised $60m in a second-round financing last August after coming out of stealth mode with a $40m Series A in early 2017.

The deal adds to Pfizer’s rare disease portfolio, which just chalked up a major success with the approval of tafamidis products Vyndaqel and Vyndamax for transthyretin amyloid cardiomyopathy (ATTR-CM) earlier this week.

Pfizer has been steadily adding to its rare disease assets via a series of takeovers and alliances to complement its own R&D in this area.

TA-46 will add to other pipeline candidates including Sangamo-partnered haemophilia A gene therapy SB-525, VTX-801 for the treatment of Wilson's disease that was acquired along with a 15% stake in Vivet Therapeutics earlier this year, and in-house mini-dystrophin gene therapy candidate PF-06939926 for Duchenne muscular dystrophy.

Pfizer's Mikael Dolsten

“At Pfizer, our strategy is focused on advancing the most promising science in the world, regardless of whether it is found inside or outside of our labs,” said Mikael Dolsten, the company’s chief scientific officer.

“By acquiring Therachon, we hope to leverage Pfizer’s leading scientific and development capabilities to more rapidly advance this potentially promising therapy for people with achondroplasia.”

Therachon isn’t the only company developing a drug for achondroplasia however, and Pfizer could find itself playing catch-up with BioMarin, which has a drug called vosoritide in phase 3 testing that has already shown potential in improving height in a mid-stage trial.

Other companies with achondroplasia in their sights include Ascendis Pharma with ACP015 (phase 1) and Ribomic with RBM-007 (preclinical).