By Anna Yukhananov
WASHINGTON (Reuters) - Alexza Pharmaceutical's experimental drug for calming down patients with schizophrenia or bipolar disorder can cause severe lung problems, U.S. Food and Drug Administration reviewers said.
In review documents released late on Wednesday, FDA staff said they were unsure whether Adasuve was safe for patients, although it successfully treated their agitation.
"The division remains concerned that the true severity and extent of pulmonary toxicity in the intended treatment population is unknown," one FDA reviewer wrote.
The FDA rejected the drug in October 2010 because of breathing-related side effects.
The briefing documents suggested agency staff were skeptical the safety problems had been addressed after the company's resubmission in August.
Three injectable drugs -- Bristol-Myers Squibb's Abilify, Eli Lilly's Zyprexa and Pfizer's Geodon -- are already approved to calm down patients with the mental illnesses, but Alexza's drug would be the first that is inhaled.
Adasuve is vaporized and delivered through the company's Staccato inhaler, thus passing through the lungs and into the blood stream faster than a typical pill. Patients were noticeably calmer within 15 minutes, the FDA said.
But in clinical trials, Adasuve was linked to lung problems including severe constriction of the airway muscles, or bronchospasm, especially for people who had a history of asthma or lung disease.
To address the safety concerns, Alexza proposed screening patients for risks before treatment, and monitoring them in the hospital after they get the drug to make sure they do not have breathing problems.
But the FDA said many patients with schizophrenia or bipolar disorder are smokers, and it may be difficult to observe breathing problems in people who are agitated.
"Acutely agitated schizophrenic or bipolar patients presenting to an emergency room or other facility may be uncooperative, psychotic, and severely disorganized," wrote an FDA reviewer.
A panel of outside experts that will meet on Monday was asked to consider whether the company's strategy will address the safety issues, and will vote on whether to recommend approval of the drug.
Schizophrenia causes delusions and hallucinations, while bipolar disorder prompts alternating bouts of depression and mania. Most people with the mental illnesses are likely to become agitated at some point.
Acute agitation can cause patients to become uncomfortable, tense and restless and if untreated, patients can become threatening and violent as the agitation intensifies, Alexza has said.
The FDA declined to approve Adasuve in October 2010 because of severe side effects related to breathing seen in three early-stage safety studies. The agency also highlighted some manufacturing and engineering problems, which it said on Wednesday the company had resolved with its resubmission.
Adasuve would be the company's first FDA-approved product. Alexza said it expects the FDA to make a final decision about the drug in early 2012.
In October, Alexza said it would market Adasuve with medical device maker Grupo Ferrer International in several regions outside the United States, including Europe and Latin America.