An experimental eye drug from Genentech Inc and Novartis AG, when used in combination with an established drug, helped forestall blindness in an early-stage study, but showed an increased risk of a serious side effect, Genentech said on Tuesday.
Researchers studied Lucentis, an injectable treatment for wet age-related macular degeneration, in combination with Visudyne, an established drug by QLT Inc and Swiss drugmaker Novartis.
Genentech said about 90 percent of patients maintained or improved vision when treated by the combination, compared with about 68 percent of those treated with Visudyne alone. The combination therapy also appeared to improve vision after one year.
But a preliminary analysis of the data showed an increased risk of serious uveitis in patients treated with the combination therapy versus those treated only with the Visudyne. Full one-year results of the Phase I/II study will be released in mid-July.
Uveitis is an inflammation in the pigmented inside lining of the eye, the uvea, that can rapidly damage the eye and produce long-term vision-threatening complications.
Wet form age-related macular degeneration or AMD, a leading cause of blindness in older adults, is a condition in which leaking blood vessels form in the eye and eventually block vision. Lucentis is an antibody designed to block formation of those blood vessels.
Patients in the combination therapy trial, dubbed Focus, had a sub type of wet AMD called predominately classic, which is based on the pattern the abnormal blood vessels take.
Merrill Lynch analyst Eric Ende, in a research note, said the safety profile of the two drugs used in combination "may temper use."
Ende said he does not expect the latest results of Lucentis in combination with Visudyne to pose a serious risk to the commercialisation of Lucentis. But he said more safety and efficacy data may be needed to drive sales of the combination therapy.
Earlier in May, Genentech and Novartis released preliminary results from a large-scale study of Lucentis alone that showed about 95 percent of patients maintained or improved their vision after a year. Patients in that trial had minimally classic or occult wet AMD, two other subgroups of the disease.
Genentech and marketing partner Novartis are conducting an additional late-stage study of Lucentis as a monotherapy in predominately classic wet AMD. The companies expect results of that trial, dubbed Anchor, in the fourth quarter of 2005.
The companies expect to file for regulatory approval in Europe and the United States early in 2006.
In a recent interview, a Novartis executive said the company expects the total market for drugs like Lucentis could eventually top $1 billion a year.
Pfizer Inc and Eyetech Pharmaceuticals Inc market Macugen, a competing drug. Last week, rival Alcon Inc received an approvable letter from US regulators, spelling out final conditions under which its wet AMD drug, Retaane, could be approved.