* Deal contingent on Ceptaris drug winning FDA backing
* Ceptaris drug Valchlor set to be addressed by FDA in Aug
* Actelion says deal will add to earnings by end-2014
ZURICH, July 31 (Reuters) - Europe's largest biotech company Actelion said it will acquire Ceptaris, a privately held U.S.-based specialty pharmaceutical company developing a topical drug, Valchlor, to treat a form of cancer.
The move is an attempt by Actelion to seek new products to replace top-seller Tracleer, a treatment for pulmonary arterial hypertension (PAH), which makes up about 87 percent of sales.
Allschwil-based Actelion said it already paid Ceptaris $25 million and will pay another $225 million when the deal closes. The deal is contingent on Valchlor clinching approval from the U.S. health regulator.
"We expect the transaction to become cash-accretive before the end of 2014," Actelion executive Nicholas Franco said in a statement on Wednesday.
Earlier this month, Actelion raised its full-year profit forecast on cost-savings and better than expected sales of Tracleer.
If approved, Valchlor would be the first treatment applied through the skin to treat early-stage mycosis fungoides, the most common type of skin T-cell lymphoma. U.S. health regulators are set to decide on Valchlor on Aug. 27.
Alongside its PAH drugs, Actelion is also developing a treatment for skin disease psoriasis as well as an antibiotic for patients suffering from Clostridium difficile-associated diarrhea.