Drug delivery technology developed by BioDelivery Sciences International (Nasdaq: BDSI) has withstood another patent challenge from competitor MonoSol Rx.

Specialty pharmaceutical company BDSI said that the U.S Patent & Trademark Office has rejected all of the claims asserted by MonoSol in the latest patent claim. Both companies have technologies that deliver drugs via a small piece of film that dissolves in the mouth. BDSI’s Onsolis, a product designed to quickly deliver a pain-killer to cancer patients, is placed on the inside of the cheek. MonoSol’s products are placed beneath the tongue.

But New Jersey-based MonoSol wasn’t claiming that Onsolis itself infringed on its patents. MonoSol said that BDSI’s Onsolis manufacturing process infringed on its patents.

MonoSol had filed a patent infringement lawsuit against Raleigh-based BDSI in 2010. The USPTO last year rejected patent claims in that suit. Last September, MonoSol added two additional patents to its suit. With the latest patent decision, the USPTO has now rejected all of the claims in two of three patents asserted against BDSI. BDSI expects a USPTO decision on the third patent shortly.

Onsolis is BDSI’s only commercialized product. The other candidates in the company’s drug pipeline all utilize the same drug delivery technology. BDSI last month licensed candidate BEMA Buprenorphine to Endo Pharmaceuticals (NASDAQ:ENDP) in a deal that could pay BDSI up to $180 million if the chronic pain treatment reaches development and commercialization milestones. BDSI is also developing another product on its own, a treatment for opioid dependence.

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