What happened

Shares of Radius Health (RDUS -0.61%), a commercial-stage biopharma primarily focused on diseases of the bone, were up 10% as of 3:15 p.m. EDT on Monday after the company reported data from a phase 1 clinical trial.

So what

Radius provided investors with an update from its 40-patient ongoing phase 1 study of its pipeline candidate elacestrant, or RAD1901. This drug is being studied as a potential treatment for estrogen-receptor-positive breast cancer.

Here's a look at the key data that was released today at the American Society of Clinical Oncology annual meeting:

  • Elacestrant demonstrated a 23% objective response rate in patients who were heavily pre-treated as of the cut-off date of April 28. 
  • The 400 mg patient group with mature data demonstrated a median progression-free survival rate of 4.5 months and a clinical benefit rate of 42% after 24 weeks.
  • Fifteen of the 40 patients remained on treatment as of the cut-off date.

This data was impressive given that all of the patients in the study had received a median of three prior lines of treatment. In addition, elacestrant was well-tolerated by patients.

Dr. Aditya Bardia, a director at Mass General, said, "While still early, the single-agent clinical activity and safety profile demonstrated with elacestrant in this heavily pretreated advanced hormone receptor positive breast cancer patient population is encouraging when compared to the results shown for other agents in a similar setting."

The upbeat clinical news caused traders to cheer.

Doctor giving thumbs-up

Image source: Getty Images.

Now what

While there's no doubt that elacestrant is an intriguing compound, Radius Health's immediate future hinges on a successful rollout of Tymlos. This drug just won FDA approval on April 28 as a treatment for osteoporosis in postmenopausal woman and was recently launched. Shareholders have their fingers crossed that the drug can live up to its full potential.

That might not be easy given that Tymlos comes with a black-box warning of an increased risk of developing osteosarcoma, a type of bone tumor. On the flip side, Radius just reported data from a 3.5-year-long study of Tymlos that showed patients who used the drug had an 84% relative risk reduction in the incidence rate of new vertebral fractures when compared to placebo. That could be a strong enough argument to convince patients and providers alike to give the drug a try.