Amgen's experimental injection leads to 20% average weight loss in key trial

Amgen has announced that its experimental weight loss injection, MariTide, helped patients with obesity lose up to 20% of their body weight on average after a year in a critical mid-stage trial. For those with both obesity and Type 2 diabetes, the drug led to weight loss of up to 17%. The company reported no plateau in weight loss, suggesting potential for further reductions beyond the 52-week trial period.

MariTide was administered monthly or less frequently, which could provide an edge over the popular weekly injections currently on the market. However, Amgen’s shares fell by 10% following the announcement, as the results were seen as falling short of Wall Street’s expectations. Analysts had hoped for a weight loss of at least 20%, with some predicting up to 25%.

The trial, which tested various dosing schedules and regimens, indicated that patients who received the highest dose every other month experienced similar weight loss results to those who took it monthly. The trial also assessed how long participants could go between injections while still achieving weight loss, suggesting that less frequent dosing might be feasible.

Amgen CEO Robert Bradway emphasized the drug’s "unique differentiated and competitive profile" and said the company plans to explore this further in Phase 3 development. Chief Scientific Officer Jay Bradner revealed that the company is already planning its late-stage study, using the data from this trial to fine-tune its approach.

Although promising, Amgen's MariTide faces tough competition from existing weight loss drugs like Novo Nordisk's Wegovy and Eli Lilly’s Zepbound, which have already proven effective in the market. Wegovy, for instance, helps users lose 15% of their weight over 68 weeks, while Zepbound results in more than 22% weight loss over 72 weeks.

MariTide, which employs a new approach using a peptide antibody conjugate, could set itself apart due to its potentially fewer injections and devices compared to current weekly injectables. Unlike Zepbound, which activates both GIP and GLP-1 hormones, MariTide targets GLP-1 and blocks GIP receptors, offering a different mechanism of action.

Amgen is also testing the durability of weight loss after a year of treatment, with some patients continuing the trial on lower doses or a placebo. The second part of the trial will assess how long-lasting the weight loss is and whether further reductions in weight are possible.

Despite the mixed market reaction, Amgen’s efforts to carve a niche in the expanding weight loss drug market, which analysts predict could be worth $150 billion by the 2030s, are underway.