In a move aimed at overcoming one of gene therapy’s biggest bottlenecks, Genethon and Ampersand Biomedicines have announced an exclusive partnership to design a new class of adeno-associated virus (AAV) vectors with significantly improved tissue specificity.

 

The collaboration brings together Genethon, a French leader in gene therapy development for rare diseases, and Ampersand Biomedicines, a Flagship Pioneering company focused on highly targeted medicines that act only at disease sites. Together, the two groups plan to engineer AAV capsids capable of reaching intended tissues with far greater precision than current systems allow.

 

AAV vectors are widely used in gene therapy for their strong therapeutic potential, but their natural tendency to accumulate in the liver remains a major limitation. This “liver tropism” often forces clinicians to use higher doses to reach other tissues—raising concerns around safety, immune response, and overall cost.

 

Under the agreement, the partners will jointly design, test, and develop novel AAV vectors intended to overcome these constraints by improving delivery accuracy and reducing off-target exposure.

 

“Precision targeting is a key driver for improving both the efficacy and tolerability of gene therapy. By directing the vector exclusively to the tissues of interest, higher potency with lower doses can be used, systemic exposure is reduced, and immune responses can be minimized. 

 

"We are delighted with this collaboration with Ampersand Biomedicines, which combines cuttingedge AI-powered drug design technology with Genethon’s expertise in gene therapy, and opens up new perspectives for novel generation AAV-gene therapies,” emphasizes Frédéric Revah Chief Executive Officer of Genethon.

 

Ampersand Biomedicines CEO Jason Gardner echoed the ambition behind the partnership, emphasizing the company’s focus on ultra-precise drug delivery.

 

“At Ampersand, we aim to address one of medicine’s central challenges: delivering therapies exactly where they are needed,” said Jason Gardner, Chief Executive Officer and President of Ampersand Biomedicines and CEO-Partner at Flagship Pioneering. 

 

“Since our founding, we have identified exquisitely selective ligands to specific cells across every major tissue and cell type in the human body, enabling a new level of precision in therapeutic targeting. By combining our unique targeting capabilities with Genethon’s expertise in AAV engineering, we are looking forward to contributing to the next generation of safer and more efficacious therapies with the potential to transform patient outcomes.”

 

The collaboration will leverage Ampersand’s Address, Navigate, Determine (AND) Platform, which combines computational tools and antibody discovery technologies to identify highly specific tissue-targeting ligands. Central to the system is its proprietary Address Map, which maps optimal biological “addresses” for precise drug delivery.

 

In the partnership, Ampersand will supply tissue-specific ligands while Genethon incorporates them onto AAV capsids to enhance targeting accuracy. The initial focus will be skeletal muscle, a core area of expertise for Genethon, with plans to expand into additional tissues and organs over time.

 

Together, the companies aim to push gene therapy toward a new standard—treatments that are more precise, safer, and more effective by design.