Chapter 4: Clinical Trials for Weight Loss Drugs

The field of obesity pharmacotherapy is pretty busy these days, with scientists working hard to make treatments that work better and don’t cause as many side effects. There are several promising medications going through clinical trials right now that might really change how we handle weight loss in the future.

What Are Clinical Trials For Overweight And Obesity?

Clinical trials for overweight and obesity are research studies that aim to find new ways to prevent, detect, or treat these conditions and improve the quality of life for affected individuals. These trials involve volunteers who participate under the guidance of healthcare professionals and researchers.

Clinical trials for overweight and obesity follow these main steps:

Pre-clinical: Lab and animal testing to assess safety and potential.

Phase 1: Small group (20-100) to check safety and side effects.

Phase 2: Larger group (up to a few hundred) to test effectiveness and further assess safety.

Phase 3: Large, diverse group (up to thousands) to confirm effectiveness, monitor side effects, and compare to existing treatments. Successful Phase 3 leads to potential approval.

Phase 4: Post-market monitoring for long-term safety and effectiveness in real-world use.

Registered Clinical Trials for Weight Loss Drugs

Phase 3 Trials

Phase 3 trials are the final testing stage before medications can be approved. Your doctor might be excited about several drugs that are almost ready:

1. Cagrilintide and Semaglutide (CagriSema)

This is a combo treatment from Novo Nordisk that puts together semaglutide, which works on something called GLP-1 receptors, with cagrilintide, which mimics a hormone called amylin. You’d get it as a once-weekly shot under your skin. In Phase 3 testing, people lost around 22.7% of their weight on average. We might see CagriSema approved around late 2025.

2. Orforglipron (LY3502970)

Eli Lilly makes this one. It’s a daily pill that works on GLP-1 receptors, but it’s not a protein like other similar drugs – it’s a smaller molecule. Right now it’s in Phase 3 trials in what they call the ATTAIN program. Earlier studies showed people might lose up to 15% of their weight, and it could be approved in early 2026.

3. Retatrutide (LY3437943)

Another one from Eli Lilly, retatrutide is special because it works on three different receptors at once – GIP, GLP-1, and glucagon. You’d take it as a once-weekly shot, and it’s being tested in the TRIUMPH program. Earlier data showed people lost up to 24% of their weight over 48 weeks – that’s pretty significant. It might be approved by 2027.

4. Survodutide (BI 456906)

Two companies, Boehringer Ingelheim and Zealand Pharma, are working on this one together. It works on both GLP-1 and glucagon receptors. You’d get it once a week as a shot under your skin, and it’s in Phase 3 trials in the SYNCHRONIZE program. Earlier results showed nearly 19% weight loss after 46 weeks, and it might be available in 2027.

5. Mazdutide

This one’s made by Innovent Biologics, and like survodutide, it works on both GLP-1 and glucagon receptors. You’d get it as a shot under your skin, and it’s currently in Phase 3 trials.

6. Oral Semaglutide (higher doses)

Novo Nordisk is testing stronger versions (25mg and 50mg) of oral semaglutide, which is already approved as Rybelsus for type 2 diabetes. A Phase 3 study (they call it the OASIS program) showed weight loss of up to 15% with these higher doses, and it might be available in 2026.

Phase 2 Trials

There are other promising weight loss medications that aren’t quite as far along. They’re in Phase 2 clinical trials right now:

1. Amycretin (NN9487)

Novo Nordisk is making this drug that works on GLP-1 and amylin receptors. They’re developing it both as a daily pill and as a shot. Early trials of the pill showed about 13% weight loss over just 12 weeks. They’re also testing the shot version, and we’ll hear more about mid-stage trial results in early 2026.

2. MariTide (maridebart cafraglutide, AMG 133)

Amgen’s MariTide is a pretty special drug that both activates GLP-1 receptors and blocks GIP receptors. You’d get it as a shot, maybe just once a month or even less often. Phase 2 studies showed up to 20% average weight loss after a year, and they’re planning bigger Phase 3 trials now.

3. VK2735

Viking Therapeutics is working on VK2735, which targets both GLP-1 and GIP receptors. They’re making both a shot and a pill form. Phase 2 results for the shot showed up to 13.1% more weight loss than placebo, and early testing of the pill form also shows it helps with weight loss.

4. Pemvidutide

Altimmune’s pemvidutide works on both GLP-1 and Glucagon receptors and is given as a shot under your skin. Phase 2 trials should be wrapping up soon.

5. Bimagrumab

Eli Lilly’s bimagrumab is a different kind of treatment – it’s an antibody that attaches to activin receptors. You’d get it through an IV once a month. It’s in Phase 2 trials and might help improve your body composition while you’re losing weight.

6. ARD-101 (Denatonium Acetate)

Aardvark Therapeutics is studying ARD-101, which is interesting because it activates bitter taste receptors in your digestive tract. This makes your body produce hormones that help control appetite. Right now it’s in Phase 2 trials for a condition called Prader-Willi syndrome and is also being studied for obesity caused by hypothalamic problems.

7. GSBR-1290

Structure Therapeutics is testing GSBR-1290, which is a small molecule pill that works on GLP-1 receptors. It’s in Phase 2b studies right now, and we should hear results in late 2025.