A new drug which destroys blood supply to fatty tissue could help people lose a tenth of their body weight in just one month, a study indicates. Obese rhesus monkeys lost on average 11 per cent of their body weight after four weeks of the experimental treatment.
Body mass index (BMI) and waistline also were reduced, while all three measures were unchanged in untreated control monkeys.
Imaging studies also showed a substantial decrease in body fat among treated animals.
A research team led by scientists at The University of Texas MD Anderson Cancer Centre carried out the study.
Co-senior author Professor Renata Pasqualini, at the David H. Koch Centre for Applied Research of Genitourinary Cancers, said: “Development of this compound for human use would provide a non-surgical way to actually reduce accumulated white fat, in contrast to current weight-loss drugs that attempt to control appetite or prevent absorption of dietary fat.”
She said previous attempts to treat obesity have predominantly focused on drugs aimed at suppressing appetite or increasing metabolism, but these efforts have been hampered by their toxic side-effects.
The MD Anderson group designed a new drug, which includes a homing agent that binds to a protein on the surface of fat-supporting blood vessels and a synthetic peptide that triggers cell death.
Their blood supply gone, fat cells are reabsorbed and metabolised.
Co-senior author Professor Wadih Arap, said: “Obesity is a major risk factor for developing cancer, roughly the equivalent of tobacco use, and both are potentially reversible.”
In earlier preclinical research, obese mice lost about 30 per cent of their body weight with the drug, now called Adipotide.
The drug acts on white adipose tissue, the scientific name for the unhealthy type of fat that accumulates under the skin and around the abdomen, and is a disease and mortality predictor.
Prof Pasqualini said: “Most drugs against obesity fail in transition between rodents and primates. We’re greatly encouraged to see substantial weight loss in a primate model of obesity that closely matches the human condition.”
The primate model also shares other physiological features associated with human obesity, such as metabolic syndrome, characterised by an increased resistance to insulin, which can lead to the development of type 2 diabetes and cardiovascular disease.
Adipotide-treated monkeys showed marked improvements in insulin resistance – using about 50 per cent less insulin after treatment.
Now the research team are preparing for a clinical trial in which obese prostate cancer patients would receive daily injections of Adipotide for 28 consecutive days.
Prof Arap said: “The question is, will their prostate cancer become better if we can reduce their body weight and the associated health risks?”
He said some prostate cancer treatments, such as hormone therapy, cause weight gain.
Greater weight can lead to arthritis, which in turn causes inactivity that leads to more weight gain.
Fat cells also secrete growth hormones that cancer cells thrive on.
Weight, BMI and abdominal circumference all continued to drop for three weeks after treatment ended before turning back up during the eighth week of the study.
Treated monkeys’ abdominal fat levels fell by 27 per cent during the study. Fat levels increased slightly in the control group.
Lean monkeys did not lose weight in a separate study to test for potential effects of the drug in non-obese animals, indicating that the drug’s effect may be selective for obese subjects.
Monkeys in the studies remained bright and alert throughout, interacting with caretakers and demonstrating no signs of nausea or food avoidance.
This is potentially an important finding since unpleasant side-effects have limited the use of approved drugs that reduce fat absorption in the intestines.
The principal side effects were noted in the kidneys.
Study first author Dr Kirstin Barnhart, a veterinary clinical pathologist said: “The renal effect was dose-dependent, predictable and reversible.”