Shares of Carlsbad-based Isis Pharmaceuticals Inc. have risen nearly 10 percent since the recent announcement that its flagship cholesterol drug, Kynamro, was approved by the U.S. Food and Drug Administration.

Thanks to the FDA approval, Isis will receive a $25 million milestone payment from Boston-based Genzyme, a unit of French drug maker Sanofi SA.

Isis has been developing Kynamro with Genzyme to treat patients with a rare form of high blood cholesterol called homozygous familial hypercholesterolemia, which can cause heart attacks at a young age. Ten years of research and $350 million from Genzyme Corp. have been invested in Kynamro, according to regulatory filings.

The approval comes in spite of the fact that Kynamro recently failed to get approval from a European Union regulatory committee because of concerns that it may cause liver damage and other severe side effects in patients. Genzyme is expected to seek a re-examination of the EU decision.

Isis shares were traded at $14.69 at market close on Jan. 30, up from $13.38 before the announcement was made. And the stock has risen significantly since the European committee’s dismissal of the drug in December, when the stock was hovering around $10 a share. It trades on the Nasdaq with the ticker symbol ISIS.

The company, which operates with a relatively lean 345 employees, has a broad pipeline of first-in-class drugs in development — 18 drugs in clinical development and five more in pre-clinical study. Kynamro is its first major FDA win – it also received approval for HIV medication Vitravene in 1998, but had little market impact.

Since its 1989 launch, Isis has raised nearly $3 billion in venture capital and partnerships with companies such as GlaxoSmithKline PLC, Pfizer Inc. and Novartis AG. The publicly traded company’s market cap has risen to about $1.49 billion.

— Meghana Keshavan