Experimental cancer drug may strengthen bones in postmenopausal mice

After eight weeks of treatment, postmenopausal mice in a University of East Anglia experiment had more bone volume and better-preserved internal structure than untreated animals. They also weighed less and carried less body fat, even though both groups ate the same amount.

The compound, CADD522, was originally designed to block RUNX2, a protein involved in the growth and spread of several cancers. To model menopause-related hormonal changes, the researchers used mice that had undergone surgery. Scans showed that the treatment preserved the delicate, honeycomb-like architecture inside bones, while blood tests suggested it encouraged new bone growth without interfering with normal bone renewal.

The effect reached beyond the skeleton. Treated mice had fewer fat deposits building up inside their bone marrow, and analysis of brain tissue found that beneficial omega-3 fats, including DHA, remained largely intact. Several other lipid changes associated with menopause shifted toward healthier patterns. The team did not test memory or thinking, so any effect on those functions remains an open question.

Early safety results offer a reason to continue, not a reason to prescribe. In experiments involving mice, rats and dogs, CADD522 appeared to be taken orally and well tolerated. The researchers also reported that the compound seemed to be metabolized more slowly in human tissue than in rodents, which could potentially improve its performance in people. Those findings do not replace human trials: the treatment has so far been tested only in animals.

So what, concretely? If later studies reproduce the result in people, one medicine could potentially address two problems associated with menopause: weaker bones and increased body fat. That matters because osteoporosis affects around one in three women over the age of 50, according to lead researcher Darrell Green. For now, the practical gain is a promising direction for drug development, not a new treatment; Green says the team hopes it may ultimately reduce fracture rates.