Pfizer has acquired the remaining stake in Bamboo Therapeutics, a privately held gene therapy group based in Chapel Hill, North Carolina, USA, in a deal that could be worth as much as $645 million. Having bought 22% of the firm’s fully diluted equity during the first quarter of 2016, the US drugmaker has now paid $150 million to acquire the remainder. Bamboo is now a wholly-owned subsidiary of Pfizer.

Under the terms of the transaction, Bamboo’s shareholders will also be eligible for potential milestone payments of up to $495 million contingent upon the progression of key assets through development, regulatory approval and commercialization. The purchase boosts Pfizer’s expertise in gene therapy, adding clinical and several pre-clinical assets, an advanced recombinant Adeno-Associated Virus (rAAV) vector design and production technology, and a fully functional Phase 1/11 gene therapy manufacturing facility.

An emerging area of medical research, gene therapy is focused on highly specialized, one-time transformative treatments that address the root cause of diseases caused by genetic mutation.  Genetic material can be delivered to the body to compensate for a defective gene, most frequently by using a viral vector such as rAAV.

"We believe that gene therapy may hold the promise of bringing true disease modification for patients suffering from devastating diseases, and we hope to see this promise come to fruition – through new and existing in-house capabilities and potential partnership opportunities in the years to come," said Mikael Dolsten, president of Pfizer Worldwide Research & Development.

Bamboo’s portfolio includes potential best-in-class rAAV -based gene therapies that will complement Pfizer’s portfolios in two key areas: neuromuscular, with a pre-clinical asset for Duchenne Muscular Dystrophy (DMD) and  central nervous system with pre-clinical assets for Friedreich’s Ataxia and Canavan disease, and a Phase 1 asset for Giant Axonal Neuropathy.

No gene therapy products have been approved in the US to date.