New slimming drug reduces weight by up to 22.5%, study shows

An experimental drug, undergoing clinical investigation for its effects on obese or overweight people, has provided record weight loss results for study participants – along with surgical options, as assured by the responsible pharmacist.

Tirzepatide, developed by the American pharmaceutical company Eli Lilly and Company (Lilly), is a weekly injection that promotes weight loss by mimicking the effects of natural hormones known as incretins. These hormones can reduce blood sugar after a meal, as well as regulate metabolic processes related to digestion.

The new drug is not yet available on the market, as it awaits further clinical studies, but it results from a synthetic combination of two specific incretins, called GLP-1 (glucagon-like peptide-1) and GIP (gastric inhibitory peptide).

GLP-1 is the basis of the antidiabetic drug ‘semaglutide’, which was approved in the US for weight loss in 2021, the first time the FDA has given the OK to a new weight loss treatment. This approval was granted based on results described as “game changers” for weight loss but it appears that the tirzepatide formula could change the game again.

In the results of the phase 3 clinical trial, the investigators enrolled 2,539 overweight or obese participants (with a weight-related comorbidity but without type 2 diabetes). Participants received either tirzepatide or a placebo for 72 weeks, along with support to follow a low-calorie diet and increase their physical activity levels. The drug was given in three different doses — 5, 10 or 15 milligrams in the weekly injection — but all three groups had significant levels of weight loss over the course of the study.

At the highest dose (15 mg), participants saw average weight reductions of 22.5% of body weight (24 kg), while the 10 mg dose achieved 21.4% weight loss (22 kg); at 5 mg, there was a reduction in body weight of 16% (16 kg).

In comparison, the placebo group lost only 2.4% of their body weight (2 kg). Weight loss trials with semaglutide had an average weight loss of approximately 17%.

“Tirzepatide is the first investigational drug to show more than 20% weight loss on average in a phase 3 study,” said clinical research physician Jeff Emmick, vice president of product development at the drugmaker, which is expected to announce the study results in 2023.