Johnson & Johnson said on Monday it will buy neurological drugmaker Intra-Cellular Therapies for $14.6 billion, its biggest deal in at least two years, boosting its presence in the market for brain disease treatments.

The deal is meant to help J&J boost its growth in the drugs and medical devices businesses after it spun off the consumer health unit in 2023. The company's blockbuster psoriasis drug Stelara is also set to face competition from several biosimilar versions in the U.S. this year.

Meanwhile, Drugmaker Biogen will buy all outstanding shares of Sage Therapeutics that it does not already own for $7.22 apiece, a filing showed on Friday, sending the latter's stock up 34% in extended trade.

As per the filing, Biogen has a 10.2% stake in Sage Therapeutics. The offer price, representing a 30% premium to the stock's close on Friday, values Sage's equity at $441.7 million, according to Reuters calculations.

Intra-Cellular Therapies and Sage Therapeutics shares both surged over 34% in morning trading.