Breast cancer remains the most prevalent cancer among women worldwide, with 2.3 million diagnoses and 670,000 deaths reported in 2022.

Standard treatments for breast cancer often involve surgery followed by long-term hormone therapy, which can lead to significant side effects and does not eliminate the risk of cancer recurrence or resistance.

Approximately 70% of breast cancer cases are estrogen receptor-positive (ER+), highlighting the need for more effective therapies that specifically target this type.

Researchers at the University of Illinois at Urbana-Champaign have developed a new drug, ErSO-TFPy, which specifically targets ER+ breast cancers, aiming to minimize side effects and enhance patient outcomes.

In 2022, the research team synthesized new derivatives of ErSO, demonstrating improved potency and selectivity for ER+ cancer cells compared to the original compound.

Professor Paul Hergenrother, the study's lead, remarked on the rarity of such effective results from a single dose, noting that it's unusual for a compound to completely eliminate tumors in this manner.

The breakthrough treatment, ErSO-TFPy, has shown promise in eliminating small breast tumors and significantly shrinking larger tumors in mice with just a single dose.

In experiments, ErSO-TFPy not only shrank transplanted human breast tumors in mice but also showed no significant adverse effects during treatment.

The study, which received funding from the National Cancer Institute and the Cancer Center at Illinois, was published on January 22, 2025, in ACS Central Science.

The researchers propose that the reduced circulation time of ErSO-TFPy could lower the risk of side effects and long-term complications associated with cancer treatment.

The research team believes that a treatment regimen involving just one or a few doses of ErSO-TFPy could revolutionize breast cancer care and significantly improve patient quality of life.

This novel drug is derived from a previously developed compound called ErSO, which targets the estrogen receptor-positive breast cancer cells that most breast cancers depend on for growth.