(Reuters) - Rare disease drugmaker PTC Therapeutics Inc (>> PTC Therapeutics, Inc.) is exploring a potential sale amid takeover interest from several pharmaceutical companies, including Shire Plc (>> Shire PLC) and BioMarin Pharmaceutical Inc (>> BioMarin Pharmaceutical Inc.), according to people familiar with the matter.

The company, which treats a muscle-wasting disorder known as Duchenne, is working with financial advisers as it weighs strategic alternatives, said the sources, who asked not to be named because the matter is private.

Representatives for South Plainfield, New Jersey-based PTC Therapeutics could not be reached for comment. Representatives for Shire and BioMarin declined to comment.

The stock of PTC Therapeutics, which has a market valuation of roughly $2 billion, rose as much as 25 percent to $68.44 on reports of the potential sale, before easing to $63.51, up 15.1 percent.

Makers of treatments for rare diseases, also known as orphans, are attractive acquisitions for large pharmaceutical companies looking to offset a drop in sales as patents on their blockbuster products expire.

Prosena Holding NV, which also makes a treatment for Duchenne, was acquired last November by BioMarin for $840 million.

PTC Therapeutics' drug Translarna has received orphan drug status in the European Union and the United States and is in process of seeking U.S. Food and Drug Administration approval.

Shire Plc could be interested in acquiring PTC Therapeutics to add to its portfolio of rare disease drugs, the sources added.

Shire has made several acquisitions to bolster its focus on rare diseases, including a $5.2 billion purchase of NPS Pharmaceuticals in January and a $4.2 billion deal for ViroPharma last year.

It also took a look at acquiring Salix Pharmaceuticals Ltd (>> Salix Pharmaceuticals, Ltd.) in recent weeks but ended up passing on the deal, according to sources.

(Reporting by Olivia Oran and Soyoung Kim in New York; Editing by Christian Plumb and Jeffrey Benkoe)

By Olivia Oran and Soyoung Kim