French drug company Sanofi has agreed to buy Cambridge, England-based immunotherapy firm Kymab for up to $1.45 billion.

Kymab is a clinical-stage biopharmaceutical company developing fully human monoclonal antibodies with a focus on immune-mediated diseases and immuno-oncology therapeutics.

Sanofi will acquire Kymab for an upfront payment of $1.1 billion and up to $350 million upon achievement of certain milestones.

The transaction will result in Sanofi having full global rights to KY1005, a fully human monoclonal antibody that “has a novel mechanism of action.”

Sanofi said: “KY1005 binds to OX40-Ligand and has the potential to treat a wide variety of immune-mediated diseases and inflammatory disorders.”

Sanofi CEO Paul Hudson said: “The Kymab acquisition adds KY1005 to our dynamic pipeline, a potential first-in-class treatment for a range of immune and inflammatory diseases.

“The novel mechanism of action may provide treatment for patients with suboptimal responses to available therapies.

“We understand from our ongoing work in debilitating immunological diseases how critical it is to find the right treatment for each patient.

“We look forward to rapidly developing this investigational medicine.”

Kymab CEO Simon Sturge said: “The agreement is a testament to the commitment, drive and expertise of the entire Kymab team and we are pleased to receive this endorsement from Sanofi.

“With its significant global resources, we believe Sanofi is the perfect partner to progress Kymab’s pipeline of products and the merger will expedite the time it takes for our novel therapies to get to patients.”