Eisai has suffered a setback with the news that US regulators have turned down a patch version of its Alzheimer’s disease blockbuster Aricept.

The Japanese drugmaker revealed that the US Food and Drug Administration has issued a complete response letter to its partner Teikoku Pharma USA, regarding the New Drug Application of the Aricept Patch (donepezil transdermal system). The patch was developed by the subsidiary of Teikoku Seiyaku Co and the partners are looking for its approval as a weekly treatment of mild, moderate and severe stages of Alzheimer’s.

No details about the contents of the letter has been disclosed and Eisai just noted that the FDA has deemed the NDA as not ready for approval. The Tokyo-based firm will work with Teikoku to “determine next steps”. If approved, the patch will be co-promoted with long-time Aricept partner Pfizer.

Eisai is hoping the patch and a recently-approved once-daily, higher-dose version of Aricept will soften the impact of the generic version of the drug made by Ranbaxy. Aricept  lost US patent protection in November 2010, and the company said last year it expected annual US sales of the treatment to fall 60% to $800 million from $2 billion between 2011 and 2013.

However there was good news for Eisai regarding Halaven, a cancer treatment that has been enthusiastically received by oncology specialists. Halaven (eribulin mesylate) has been approved in Japan for the treatment of inoperable and recurrent breast cancer, having already received the green light in  the USA and  the European Union.

The approval is based on results of the Phase III EMBRACE trial as well as a Phase II study conducted in Japan. Halaven is the first single-agent chemotherapy to demonstrate a statistically significant overall survival benefit in patients with pretreated metastatic breast cancer and Eisai said that  against this backdrop, it has “strengthened its sales force by having all of its medical representatives trained in oncology and will make a concerted effort to provide information to ensure proper usage of the drug”.

Pancreas drug also gets green light

Japan's Ministry of Health, Labour and Welfare  has also given the green light to Abbott’s enzyme replacement drug Lipacreon (pancrelipase), which Eisai will market once it is listed on the National Health Insurance price list.

Approved for patients with pancreatic exocrine insufficiency, the therapy is already sold in over 80 countries including the other  major markets under the brandnames Creon and Kreon.