June 12 (Reuters) - Biogen's Alzheimer's drug, Leqembi, will do well in the market whether a competitor comes or not, a company executive said at the Goldman Sachs Global Healthcare Conference on Wednesday.

Leqembi, co-developed by Biogen and its Japanese partner Eisai, had won standard approval from the U.S. Food and Drug Administration last July. It sees a potential rival in Eli Lilly's experimental Alzheimer's treatment donanemab.

"Competition or another option is always a good thing," said Biogen's North America head Alisha Alaimo.

"But more importantly, the market will develop faster with Lilly in play," Alaimo said, adding that she cannot speculate what will happen with donanemab's label.

Outside advisers to the FDA unanimously backed the use of donanemab for the treatment of early Alzheimer's disease on Monday, clearing the way for a final regulatory decision on the treatment.

While the U.S. health regulator is not obligated to follow the panel's recommendations, it usually does so.

Leqembi's launch has so far been lackluster, with bottlenecks due to its requirements such as additional diagnostic tests, twice-monthly infusions and regular brain scans, which have contributed to a slower adoption of the drug than markets were expecting.

Analysts expect donanemab to ultimately be approved. Some have said having two players on the Alzheimer's drug market would help with its growth.

Leerink Partners analyst David Risinger, however, said assuming the FDA approves donanemab, its commercial adoption is expected to be limited relative to leqembi because Lilly's treatment has more safety liabilities and is less convenient with intravenous administration.

According to HSBC analysts, the two candidates — Biogen and Lilly — could start shaping a potential $100 billion market for the Alzheimer's treatments.

"While it is expensive to enter the space, once in, competition should be limited," the brokerage said in a report on Wednesday. (Reporting by Sriparna Roy in Bengaluru; Editing by Shilpi Majumdar)