By Manas Mishra and Christy Santhosh
(Reuters) -Amgen shares headed for their best session since 2009 on Friday after the U.S. drugmaker hinted at encouraging interim trial data on its experimental obesity drug, denting rival stocks but leaving analysts frustrated with a lack of details.
Weight-loss drugmaker Eli Lilly (NYSE:LLY)'s shares fell 1.6% while Novo Nordisk (NYSE:NVO)'s Denmark-traded shares dropped 3.9%, on track for their biggest one-day fall since November 2022. Smaller peer Viking Therapeutics (NASDAQ:VKTX) fell 2.3%.
Amgen (NASDAQ:AMGN) is conducting mid-stage studies of the injectable drug and said that, based on an interim analysis, it was "confident in MariTide's differentiated profile" and believes it will "address important unmet medical needs".
The company provided no specifics on the actual data, but said it plans to start a late-stage study later this year.
Investors consider moving to a late-stage trial after an interim analysis as a big positive, BMO analyst Evan Seigerman said.
"The fact that ... the delivery dosing schedule is likely to be monthly or less frequent implies far fewer injection devices than competitors who, for example, are administering a weekly therapy," Amgen CEO Robert Bradway said on Thursday.
Mizuho analyst Salim Syed said he acknowledged Amgen's "seemingly more upbeat tone" on the drug franchise but added "we'd argue that a lot of questions remain unanswered".
Besides a lack of data, Syed said those questions also included manufacturing plans, given that rivals Lilly and Novo are racing to boost supply of their respective weight-loss drugs Zepbound and Wegovy.
Amgen's drug is designed to block the activity of a gut hormone, GIP, which has been linked to fat storage and metabolic regulation. Lilly's Zepbound works by activating the GIP hormone, while Novo's Wegovy does not target the hormone.
"The hurdles for a third competitor are very high. Zepbound and Wegovy have a large safety database, as both have already been used in diabetics for years," said Markus Manns, a portfolio manager at Union Investment in Germany and a Novo shareholder.
"The biggest hurdle for any competition is to show that their product is as safe," said Manns.
Amgen's shares, part of the bluechip Dow Jones index, rose 14.2% to $317.85 in early trading, on track to add about $21 billion to its market valuation.
The company's stock is trading 13.9 times its forward 12-month earnings estimates, compared with a forward price-to-earnings ratio of 34.2 for Novo Nordisk and 48.49 for Eli Lilly.