Sanofi buys Inhibrx to boost rare disease business

French healthcare company Sanofi has agreed to buy US biotech firm Inhibrx in a deal valued at up to $2.2bn, bolstering its drug development portfolio with an experimental treatment for a rare genetic disease.

The companies said the deal will give Sanofi access to INBRX-101, now in the second of three phases of clinical trials, while Inhibrx’s other experimental drugs will be spun off into a separate company, with Sanofi retaining an 8% stake.

INBRX-101 is designed to treat alpha-1 antitrypsin deficiency (AATD), an inherited rare disease that causes progressive deterioration of the lung tissue.

Sanofi, which makes most of its revenues from anti-inflammatory treatments, last year abandoned 2025 earnings targets to boost the company’s research & development (R&D).

“The addition of INBRX-101 as a high potential asset to our rare disease portfolio reinforces our strategy to commit to differentiated and potential best-in-class products,” said Houman Ashrafian, Sanofi’s head of R&D.

US-listed shares of Inhibrx rose 6.8% to $35.60 in premarket trading on the deal that will give shareholders $30 per share in cash, which represents an equity value of $1.7bn, as well as 0.25 shares in the spun-off company.

Inhibrx shareholders will also receive a “contingent value right” equal to $5, conditioned on the achievement of a regulatory milestone.

The spun-off company will operate under the Inhibrx name and will be led by Inhibrx chief Mark Lappe as CEO.

Sanofi will assume and retire Inhibrx’s outstanding third-party debts, and fund the spun-off company with $200m in cash.

The global pharmaceuticals sector has experienced a wave of takeover deals in recent months.

Bristol-Myers Squibb said in October last year it will acquire cancer drugmaker Mirati Therapeutics for up to $5.8bn, while in March Sanofi bought Provention Bio for $2.9bn.