Excessive sedation is a serious concern following injections of a long-acting form of Eli Lilly and Co's Zyprexa schizophrenia medicine, US drug reviewers said in an analysis recently released.
The experimental formulation, called Zyprexa Adhera, was shown to be effective for acute and long-term treatment of schizophrenia, Food and Drug Administration staff said. The agency will ask an advisory panel if it finds the formulation effective and "acceptably safe."
"Excessive sedation events are a serious safety concern because of the severity of excessive sedation, the unpredictable characteristics, and relatively high incidence - 0.07 percent of injections and 1.3 percent of patients," FDA staff said in a preliminary analysis prepared for the panel meeting. Lilly said the formulation provided important benefits that outweighed the risk of sedation.
Zyprexa is Lilly's top-selling drug with nearly $4.8 billion (about R36 billion) in 2007 sales. The company currently sells it in pill form and as a short-acting injection. The long-acting version could reach $1 billion (about R7.4 billion) in annual sales if approved, Natixis Bleichroeder analyst Jon LeCroy said.
"Their pipeline is not very deep right now, and so it does have some importance," LeCroy said.
Some patients 'unarousable for hours'
The "sometimes profound" sedation seen in Lilly's studies of Zyprexa Adhera generally occurred within one to three hours, FDA staff said. Two of the 25 cases were reported as "coma" while some others were described as "deep sleep" and "un-arousable for hours."
All patients fully recovered within three to 72 hours, FDA reviewers said. Injections were given every two or four weeks.
Lilly, in a separate summary, said it believed the benefits of the long-acting formulation outweighed the risks.
"Although there are important additional safety considerations associated with the injection, they are manageable with appropriate labelling and risk-minimisation activities," the company said.
Schizophrenia is a chronic mental illness that impairs a person's ability to think clearly, relate to others and distinguish between reality and fantasy. More than 2 million Americans suffer from it, according to estimates from the National Institute of Mental Health.
As many as 65 percent of schizophrenics do not take their medicines as prescribed, causing them to relapse, Lilly said. A long-acting injection could provide an option to keep patients on therapy, the company said. "Many patients have decided that the risks are offset by robust symptom improvement, ensured medication delivery and flexibility in the dose," Lilly said.
The FDA will consider the advisory panel's input before deciding whether to approve Zyprexa Adhera. The agency is not required to follow panel recommendations but usually does.
Known generically as olanzapine, Zyprexa is part of the class known as atypical antipsychotics that were introduced in the 1990s. Zyprexa Adhera would compete with Johnson & Johnson's long-acting schizophrenia injection called Risperdal Consta. – (Reuters Health)
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