Wyeth and Elan have suspended a clinical study of their jointly developed Alzheimer’s vaccine ACC-001 after a patient receiving the treatment was hospitalized for nearly two weeks with skin ulcers.

The patient developed the skin ulcers on March 6 and Wyeth reported the findings to the FDA on March 20.

The agency asked the companies to halt the trials April 4, Wyeth spokesman Michael Lampe told Bloomberg News.

“The FDA can delay the start of a study or request no further dosing take place until the issues raised have been addressed,” Lampe said. “If they are addressed to the satisfaction of the agency, the hold can be lifted. Additional information is being gathered and will be shared with the agency.”

The patient was reported to be recovering from the skin lesions, however it remains unclear how many doses the patient received.

Analysts have forecast that the treatment could generate more than $5 billion in annual sales.
Wyeth is reported to have more than 350 scientists working on Alzheimer’s treatments and has spent more than $500 million on the disease since 2001. Meanwhile, half of Elan’s $335 million annual budget for research and development goes toward Alzheimer’s.