MariTide Phase 3 trials fill up as Amgen pitches as few as four doses a year

Amgen's MariTide Phase 3 program moved forward in the third quarter, with enrollment now complete in its heart outcomes study and both sleep apnea studies. A new Phase 3 trial that compares the drug with semaglutide in type 2 diabetes is also enrolling, the company said on 3 November. No new efficacy data came with the update. The pitch is still the schedule: Amgen says patients can start on monthly dosing and stay on treatment with as few as four or six doses a year, against 52 for a weekly shot.

What Amgen reported for MariTide

Maridebart cafraglutide, also known as AMG 133, is the molecule behind the MariTide name. Amgen describes it as an antibody peptide conjugate that switches on the GLP 1 receptor while blocking the GIP receptor, and it credits a long acting design for the monthly starting schedule. In the pipeline section of its third quarter results release, the company listed the status of each study in the MariTide Phase 3 program. The two core weight trials, MARITIME-1 in adults without diabetes and MARITIME-2 in adults with type 2 diabetes, are ongoing. Amgen gave no new weight, safety or dropout figures for any of these studies. The update is therefore a progress report on enrollment and trial starts, and it leaves the clinical picture where the Phase 2 data put it.

Three outcome studies have now finished enrolling. MARITIME-CV recruited adults with established atherosclerotic heart disease plus obesity or overweight, and the two sleep apnea trials split patients by whether they already use positive airway pressure therapy. A Phase 2b study of liver fat and weight loss in adults with elevated liver fat has also completed enrollment. MARITIME-HF, which targets heart failure with preserved or mildly reduced ejection fraction, is still enrolling. Full enrollment is a real step, because it fixes the size of each trial and starts the countdown to results. The release did not say how many people each study holds or how long follow-up lasts, so the gap between full enrollment and the first readout cannot be estimated from this report alone.

MariTide vs semaglutide in type 2 diabetes

The new head to head trial is MARITIME-T2D-3, which Amgen says was started and is enrolling adults with type 2 diabetes to compare efficacy with semaglutide, the active ingredient in Ozempic and Wegovy. Some news coverage counted a head to head start and a diabetes comparison as two separate studies. Amgen's release lists the semaglutide comparison only in type 2 diabetes, so a direct obesity trial against Wegovy is not on its published study list. The release also leaves out the primary endpoint, the trial size, the semaglutide form used as comparator and the planned length of treatment. Amgen added that two more Phase 3 studies in people with type 2 diabetes will start in the fourth quarter of 2026, which would widen the diabetes arm of the program.

Amgen's release lists the semaglutide comparison only in type 2 diabetes, so a direct obesity trial against Wegovy is not on its published study list.

A direct trial matters because cross trial comparisons in this class are weak. Populations, doses and trial lengths differ, so a percentage from one study rarely lines up with another. MariTide's Phase 2 work showed about 20 percent weight loss at one year in adults with obesity, and investors focused on tolerability at the time. Rivals have already tested themselves against semaglutide in diabetes. Lilly's weekly triple agonist retatrutide lowered blood sugar more than the top Ozempic dose in a topline Phase 3 readout, as we reported in our story on retatrutide against Ozempic. For Amgen, MariTide vs semaglutide will show whether a less frequent injection can match or beat the weekly standard on sugar control and weight together.

Fewer doses as the Amgen obesity drug pitch

The core of the Amgen obesity drug case is dosing frequency rather than peak weight loss. The company says the long acting design supports a monthly start and maintenance with as few as four or six doses a year. Two studies test that claim directly. MARITIME-SWITCH is enrolling adults who will move from weekly tirzepatide or weekly semaglutide to MariTide given every eight weeks or every quarter. Extension studies will follow people who finish the main trials. The MARITIME-1 extension tests weight maintenance with monthly, every eight week or quarterly dosing in adults without diabetes. The MARITIME-2 extension tests only monthly and every eight week dosing in adults with diabetes, so quarterly use has not been put forward for that group.

Fewer injections could help people who stop weekly drugs early. A US claims study we covered found that adults who began injectable semaglutide on a high dose had a higher risk of quitting within the year, and lower persistence over time is a known problem for the class. A monthly obesity injection might ease some of that burden, but no trial has yet shown that spacing doses out keeps the weight off. Truist Securities analysts wrote earlier this year that MariTide "remains the focal point" for Amgen, the report notes, while warning that its value depends on whether less frequent dosing holds up over long term use. That question sits with the switch and extension studies, not with this quarter's update.

What remains unknown before the 2027 readouts

Amgen's release gives no date for the first MariTide Phase 3 results, but Phase 3 readouts are expected in 2027, according to the BigGo Finance report on the quarter. Until then the efficacy picture rests on Phase 2. The same report says that roughly 20 percent average weight loss over a year trails Zepbound and sits well below the figure reported for Lilly's retatrutide. That gap may narrow or widen in larger trials with longer follow up and different dose steps; nobody can tell yet. Tolerability also remains open. Amgen has not published dropout rates from its Phase 3 studies, and the share of people who stay on treatment long enough to benefit will matter as much as average weight loss.

The financial backdrop gives Amgen time. The company reported third quarter revenue up 8 percent to $10.4 billion and non GAAP earnings per share up 14 percent to $6.45. It now guides to full year non GAAP earnings per share of $22.90 to $23.70, and it said seventeen products are annualizing at more than $1 billion in sales. MariTide is not needed to hold up current revenue, but analysts treat it as the program that matters most for the stock. Meanwhile the field keeps moving. Novo Nordisk's CagriSema is under FDA review, and oral GLP 1 pills from Novo and Lilly are already on the US market. A monthly or quarterly injection will be judged against all of these options when MARITIME data arrive.

Conclusion

The MariTide Phase 3 program is now larger and further along, with three outcome studies fully enrolled and a semaglutide comparison under way in type 2 diabetes. None of that changes what is known about efficacy, which still rests on Phase 2. The next real test is whether MARITIME-1 and MARITIME-2 show weight loss close to the weekly leaders, and whether the switch and extension studies prove that four or six doses a year can hold it. Research context only, not medical advice.