Swiss drugmaker Novartis has agreed to acquire UK-based ocular gene therapy firm Gyroscope Therapeutics for up to $1.5bn.

Under the agreement, the Swiss firm will make an upfront payment of $800m as well as potential additional milestone payments of up to $700m.

Novartis said that the deal will help add Gyroscope’s investigational gene therapy, GT005, to its portfolio.

The one-time gene therapy is currently in Phase 2 for the treatment of people living with geographic atrophy (GA).

GA is an advanced form of dry age-related macular degeneration (AMD), which also causes loss of vision. At present, there is no approved treatment for GA, said the Swiss firm.

By increasing the production of the CFI protein, GT005 aims to restore balance to an overactive complement system, a part of the immune system.

Currently, the safety and efficacy of GT005 for the treatment of GA secondary to AMD is being assessed in a Phase 1/2 clinical trial and two Phase 2 clinical trials.

The therapy has secured fast track designation from the US Food and Drug Administration to treat people with GA.

Furthermore, Gyroscope has several additional assets in its pipeline in early discovery for retinal diseases.

Novartis Pharmaceuticals president Marie-France Tschudin said: “With our own pioneering research in ocular gene therapies and our experience gained from bringing Luxturna to inherited retinal dystrophy patients outside of the US, Novartis has a well-established expertise in ocular gene therapies that will position us well to continue developing this promising one-time treatment.

“This acquisition is one more step forward in our commitment to delivering innovation in ophthalmology to treat and prevent blindness worldwide.”

The closing of the deal is subject to customary closing conditions, including regulatory approvals.

Novartis and Gyroscope Therapeutics will continue to operate as separate and independent companies until the closing of the transaction.