Shares of Atossa Therapeutics (ATOS 0.25%) continued their recent ascent on Thursday following promising announcements related to its breast cancer drug earlier this week. As of 2:50 p.m. EST, the biopharmaceutical company's stock price was up 40%.
Atossa Therapeutics said on Tuesday that "substantially positive results" from its Australian phase 2 clinical trial of Endoxifen prompted it to end the study early and accelerate the drug's development in the U.S. "It is a welcome event to halt an ongoing clinical trial because the results are so overwhelmingly positive," CEO Steven Quay said in a press release.
The first six participants in Atossa's Australian study saw an average reduction of 74% in tumor cell activity. Moreover, the patients' tumor cell activity levels dropped below a threshold that studies have shown to improve long-term survival rates.
On Wednesday, Atossa's shareholders received more good news. The biotech released 26 months of data from a single-patient compassionate-use study of Endoxifen. Atossa said the patient has not had a recurrence of breast cancer and has tolerated the treatment well. Notably, the patient did not experience side effects commonly associated with tamoxifen, a commonly prescribed treatment for breast cancer.
More than 276,000 women were diagnosed with breast cancer in the U.S. in 2020, according to The American Cancer Society. It's a far too common and often deadly disease -- one that's projected to claim the lives of more than 42,000 Americans every year.
If Endoxifen continues to demonstrate promising results in clinical trials and earns FDA approval, Atossa will likely see tremendous demand for the drug.