July 29 (Reuters) - Biogen reported second-quarter profit and revenue that topped Wall Street estimates on Wednesday, driven by strong demand ‌for its rare-disease medicines, while sales of its legacy multiple ‌sclerosis drugs stayed under pressure.

Investors are closely watching whether recent deals and newer products ​including its Alzheimer's drug Leqembi can reignite growth and help the company navigate mounting competition and pricing pressure across its aging multiple sclerosis portfolio.

Despite an upbeat quarter, Biogen cut its 2026 adjusted per-share profit forecast to ‌between $12 and $13 from between $14.25 ⁠and $15.25 per share earlier, reflecting a $3.85 per share impact from acquisition-related charges.

Analysts were expecting 2026 profit of $12.72 per ⁠share, according to data compiled by LSEG.

The drugmaker said its $5.6 billion buyout of Apellis Pharmaceuticals earlier this year would account for an 85-cent-per-share hit ​to annual ​profit.

The deal, Biogen's largest since its ​2023 buyout of Reata Pharmaceuticals, ‌gave it a foothold in kidney disease treatment and access to two approved rare disease drugs, which generated a combined revenue of about $689 million last year.

Global sales of Biogen's Alzheimer's drug Leqembi, developed with Eisai, rose 15% from a year earlier to about $184 million as demand ‌gained traction after early concerns over ​cost, efficacy and side effects tempered its ​launch.

Biogen expects recent U.S. approvals ​for a more convenient under-the-skin formulation of Leqembi to ‌drive patient uptake.

On an adjusted ​basis, it earned $3.60 per ​share for the quarter ended June 30, compared with an expectation of $2.95 per share.

Quarterly revenue came in at $2.74 billion, above an ​estimate of $2.46 billion.

Sales ‌of legacy multiple sclerosis drugs such as Tecfidera fell 13% ​to $963 million compared to the previous year.

(Reporting by Mariam Sunny ​in Bengaluru; Editing by Pooja Desai)