Amgen’s head of obesity on where its experimental GLP-1 stands

These days, it seems every pharma company wants a slice of the GLP-1 pie.

Amgen, a California-based biotech that brought in $36.8 billion in 2025, has for years been developing MariTide, a potential competitor to Eli Lilly and Novo’s blockbuster weight loss drugs. Results from a Phase 2 clinical trial released in June 2025 showed that MariTide led to participants with obesity and without Type 2 diabetes losing an average of around 20% of their body weight after a year.

The highest dose of semaglutide (Ozempic/Wegovy) was associated with trial participants losing an average of 15% of their body weight, and the highest dose of tirzepatide (Mounjaro/Zepbound) led to 21% weight loss in clinical trials.

Unlike semaglutide or tirzepatide, MariTide is an antibody-peptide conjugate. It acts as a GLP-1 agonist (meaning it boosts the effects of GLP-1 in the body) and gastric inhibitory polypeptide (GIP) antagonist (meaning it blocks GIP from being activated). Semaglutide doesn’t have a GIP component, and tirzepatide is a GLP-1/GIP agonist.

Another differentiator is the fact that MariTide is an injection given monthly instead of weekly. Amgen is also studying its effects when given once every few months.

Susan Sweeney, Amgen’s EVP of obesity and related conditions, recently gave Healthcare Brew a closer look at MariTide, where it stands in development, and what the company’s hopes are for its future.

This interview has been edited for length and clarity.

What does Amgen’s obesity treatment portfolio look like?

We have a number of products in development. Our flagship asset is MariTide, which is maridebart cafraglutide. MariTide is our nickname that we use for it, just to make it a little easier to say. We’re working on a brand name right now. It’s a really interesting molecule because it’s a long-acting antibody-peptide conjugate, which is unique in the market.

Why did you add an antibody component to it?

This is really a specialty of ours. We have developed many large antibodies that have made an impact on public health.…We knew that [obesity] treatment wasn’t just going to be short term. It’s a long-term process for patients that are living with obesity. One of the things that an antibody often confers is a longer-acting agent.

In the development of MariTide, we worked with our Amgen Reykjavik [Iceland] team, which has access to human genomics, and evaluated patients that were naturally thinner. We identified that there was a genetic variant in those patients in which they had lower GIP. We took together the knowledge and know-how of the role of GLP-1, added to it the GIP component—turning it off because they had a lower GIP—and put that together on an antibody backbone.

MariTide is being developed as a monthly agent for patients living with obesity. We also have trials going on for as little as four to six injections a year. What we know today is that the majority of patients aren’t staying on therapy…We see drop-off rates up to 50% at one year, and patients not being able to get the benefit of the weight loss, which affects their health.

You think that having fewer treatments—not having to take a weekly shot, for example—will help people stay on the medication longer?

Yeah, absolutely…When you’re taking dailies or you’re taking weeklies, that’s a constant reminder of your disease. Having an option in which you can go monthly, and then potentially once you reach your weight loss goal to go as little as four to six a year, is a bit of a release of burden from that ongoing reminder of your disease.

What stage of development is MariTide in?

MariTide is very far advanced in our Phase 3 programs. We have nine Phase 3 programs that are ongoing right now. We have the chronic weight management indications and are looking at patients living with and without Type 2 diabetes.

In addition to that, we’ve done a really extensive program of evaluating the health impact of MariTide. We have a cardiovascular outcome study that’s ongoing, a heart failure study, Type 2 diabetes studies are about to start, and we have sleep apnea as well. That’s going to be really important to understand the health benefits for patients. It’s also really important for payers. We’ve designed [the trials] to ensure that we’re looking at the health impact, and then we’ll look at the economic impact of being able to reduce that disease burden because access is so critically important.

Have you announced dates for reading out the Phase 3 data?

We have not. We fully recruited our two main pivotal programs. That’ll be the first launch that we move with. We’re just waiting for the patients to finish their treatment, and then we’ll go to launch.