NEW YORK The chief executive of Eli Lilly said a patient in ongoing trials of the company's experimental Alzheimer's disease drug solanezumab temporarily developed brain swelling, although it is not yet known whether the patient was taking the Lilly drug or a placebo.
Potentially dangerous brain swelling has been seen with high doses of a rival experimental drug being developed by Pfizer Inc and Johnson & Johnson, called bapineuzumab, and raised some doubts whether that drug will eventually be approved.
Lilly CEO John Lechleiter, speaking to investors on Tuesday at the annual JPMorgan Healthcare Conference in San Francisco, said enrollment of about 2,000 patients had been completed in two late-stage trials of solanezumab and that its overall safety so far "appears to be very good."
The two ongoing Lilly trials are still blinded -- meaning investigators have not yet been told which patients are taking solanezumab and which ones are taking placebos.
Lechleiter, whose presentation was webcast, said one patient developed asymptomatic vasogenic edema, or buildup of fluid in the brain that did not cause symptoms. But he said the problem was not seen in a followup brain scan, allowing the patient to resume treatment.
"A data monitoring committee meets on a quarterly basis and so far has suggested no changes to these trials," Lechleiter added. Such committees typically halt studies when serious safety concerns arise, or once data clearly suggest a drug is effective or ineffective.
Lilly officials could not immediately be reached for further comment about the swelling issue.
Lechleiter said his company remains enthusiastic about the infused medicine even though a different Lilly treatment for the progressive brain disease, an oral drug called semagacestat, was scrapped last summer after it was shown to worsen patient symptoms in late-stage studies.
The failure of semagacestat left solanezumab as Lilly's best hope for attacking the memory-destroying disease, although the company is testing other treatments in earlier-stage trials.
Both drugs are designed, but through different mechanisms, to block formation of amyloid plaque -- a suspected cause of Alzheimer's disease.
The company is counting on solanezumab and other experimental drugs to be approved and generate revenue to offset plunging sales of its biggest medicines, which face generic competition over the next three years.
Lilly is slated to lose U.S. patent protection on its biggest product, the $5 billion-a-year Zyprexa schizophrenia treatment, in October. Its No. 2 product, $3.5 billion-a-year antidepressant Cymbalta, faces generics in mid-2013 and its Evista osteoporosis treatment will also face generics in coming years.