Neurocrine Biosciences agreed to buy Soleno Therapeutics for $2.9 billion, paying $53 per share in cash for the Prader-Willi syndrome asset Vykat (diazoxide choline), the companies said. The deal would add Vykat’s hyperphagia treatment—an orphan indication with defined unmet need—into Neurocrine’s commercial portfolio, alongside its existing rare endocrine therapy Crenessity. Analysts have flagged both the attractiveness of near-term revenue momentum and risks around growth trajectory as the market digests the valuation and competitive outlook. For the rare-disease M&A market, the transaction reinforces how profitable post-approval platforms can attract larger acquirers even as pipeline diversification remains a board-level priority.