Amgen opens enrollment in MARITIME-2 extension testing less frequent MariTide dosing

Amgen has opened the long-term extension of its MARITIME-2 trial to enrollment, moving the Phase 3 study from "not yet recruiting" to "recruiting" on Aug. 24, 2026. The extension tests whether MariTide can maintain weight loss with monthly and every-eight-week dosing in adults with obesity or overweight who also have type 2 diabetes.

A second extension, for MARITIME-1, is running in parallel. It tests monthly, every-eight-week and quarterly MariTide dosing in participants who do not have diabetes. Both are long-term extensions, which means participants are already being treated with the drug and the question is whether the weight loss holds as doses are spread further apart.

The two extensions are where Amgen's four-to-six-doses-a-year goal for maintenance will be tested. The intervals under study run from about one month to about three months. For comparison, tirzepatide (Mounjaro, Zepbound) is described as a once-weekly medicine in a trial listing tracked by a registry monitor that follows GLP-1 studies ^[1]. Whether less frequent MariTide dosing maintains weight loss as well as dosing every month has not been reported.

Several basics about the extensions have not been disclosed. No enrollment target, completion date or expected date for results has been reported for either study. It is also not yet known whether the extensions include a placebo or another comparison group, or how long each participant will be followed.

Registry records can move before a company says anything publicly. A monitor that snapshots ClinicalTrials.gov six times a day and keeps the previous values has recorded 147 changes since tracking began on Aug. 21, 2026, including trials switching from "not yet recruiting" to "recruiting" ^[1]. ClinicalTrials.gov itself overwrites a record when it changes and keeps no public history of what it used to say ^[1].

Amgen's most recent quarterly report, released Aug. 4, 2026, put total revenue at $10.1 billion, up 10% from the second quarter of 2025. Chief executive Robert Bradway said the company is "advanc[ing] the next wave of pipeline molecules through Phase 3" ^[2]. That report covers Amgen's marketed products.

Why it matters for patients

For people on a GLP-1 medicine, the practical question is not only how much weight comes off but how often a drug has to be given to keep it off. A maintenance regimen given every eight weeks or every three months would mean fewer injections over a year than a weekly schedule. That could matter for travel, refrigeration, refills and time away from work — though cost and insurance coverage for a less frequent schedule have not been described.

None of this is established yet. The extensions are designed to measure maintenance, not initial weight loss, and no outcome data from them have been released. A result from a maintenance extension would also not, by itself, change what doctors can prescribe today. MariTide is still an investigational drug in Phase 3 testing; semaglutide (Ozempic, Wegovy, Rybelsus) and tirzepatide (Mounjaro, Zepbound) are the GLP-1 and dual-agonist medicines currently on the market, and orforglipron is an oral candidate still in trials ^[1].

What happens next

The MARITIME-2 extension is listed as recruiting as of Aug. 24, 2026, alongside the MARITIME-1 extension. Amgen has not announced enrollment targets, a completion date or a timeline for releasing results from either study, and no regulatory filing date for MariTide has been reported. Until those figures appear, how often a maintenance dose would actually be given in practice, and whether the weight loss holds at those intervals, remains unknown.