Sparks (III)

A Spark of New Life for Bimagrumab in Obesity

It was an exciting possibility. At ObesityWeek 2019, Novartis scientist Laura Coleman presented fascinating results for an experimental drug, bimagumide, in obesity. In a phase 2 study, it yielded impressive improvements in body composition for people with obesity. It wasn’t just making people lose body fat. It helped them also gain muscle mass. Then, it went quiet. Novartis would only say it was “reviewing the program strategy and evaluating next steps,” so it seemed that this exciting possibility might be dead. But now, there’s a spark of new life for bimagrumab in obesity.

Late in August, Versanis Bio emerged as a new biotech startup with $70 million in funding to develop bimagrumab for obesity and metabolic disease.

Why Is This Important?

Until now, anti-obesity medicines have tended to be all about weight loss. But weight loss is not the whole story of obesity care. Of course, excess weight is a key symptom of obesity. But the real problem is excess adipose tissue that harms health. It does this by promoting inflammation and sparking the development of other diseases – diabetes, heart disease, liver disease, cancer, and more.

Weight loss helps, of course, when it serves to reduce adiposity. But adequate lean muscle mass is also important for good health. This is why the clinical results with bimagrumab are so intriguing.

Phase 2 Results

These are early phase 2 results, so we still have much to learn. But in January, Steven Heymsfield and colleagues published detailed data from this research in JAMA Network Open. It was a study of 75 patients, randomized to placebo or bimagrumide. These were patients with a BMI that ranged from 28 to 40 who also had type 2 diabetes.

Researchers found both a increase in lean muscle mass and a profound decrease in body fat. In fact, patients lost almost 21 percent of their fat mass. They gained about four percent in lean body mass. In addition, HbA1c improved by 0.76 percentage points in this 48-week study.

These results differ from a typical study of weight loss. In most all of those studies, about 25 percent of the weight loss comes from lean body mass – not fat mass. So with bimagrumab, the eight percent total weight loss seems unremarkable until you consider that all of that weight loss is fat mass. This fact means these results may be better than results that are more typical with diet, exercise, and meds. They certainly point to more improvement in body composition.

Forget the Weight, What About Health Outcomes?

No doubt about it, bimagrumab is a fascinating new possibility for obesity treatment. But it is very different. It works on a target – the activin type II receptor – that is totally different from other anti-obesity meds. That target regulates skeletal muscle growth. But if these results are reproducible, it can also have an effect on adipose tissue.

The real story on bimagrumab is yet to be told. What will really matter is health outcomes. Drug development is a risky business, so bimagrumab might yet fail to meet expectations for a valuable advance in obesity treatment.

But at least the odds have gone up dramatically that we will learn the full story. Maybe we’ll even get an important new option for obesity care.

Click here and here for more on the spark of new life for bimagrumab in obesity. For the publication by Heymsfield et al, click here.

Sparks (III), painting by Mikalojus Konstantinas Čiurlionis / WikiArt

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September 27, 2021