Afinitor (evelolimus), a Novartis kidney cancer drug, when combined with hormonal therapy doubled breast cancer patients’ progression-free survival, and reduced cancer progression risk by 57% compared to exemestane alone, researchers revealed during a Presidential Symposium at the 2011 European Multidisciplinary Cancer Congress in Stockholm, Sweden.

Hervé Hoppenot, President, Novartis Oncology, said:

Everolimus is the first drug to show significant efficacy when combined with hormonal therapy in women with ER+HER2- advanced breast cancer, where there continues to be a critical unmet need. The magnitude of benefit seen in these patients, despite their resistance to previous hormonal therapies, shows everolimus represents a potential important new treatment approach.”

The human studies, called BOLERO-2 compared the safety and efficacy of everolimus when given together with exemestane, versus exemestane alone in postmenopausal females with ER+HER2-advanced breast cancer – whose cancer recurred or progressed while they were on or after previous treatment with letrozole or anastrazole (hormonal therapies). BOLERO-2 stands for Breast cancer trials of OraL EveROlimus-2.

BOLERO-2 was a Phase 3, double-blind, randomized, placebo-controlled multicenter trial. It included 724 patients at 189 sites around the world. Patients were randomly selected to receive:

  • Everolimus 10 mg/day orally, plus oral exemestane 25 mg/day – 485 patients, . . . . or

  • A placebo, plus oral exemestane 25 mg/day – 239 patients

Progression-free survival (PFS) improved to 6.9 months for those on everolimus compared to 2.8 months for patients on exemestane alone. Novartis added that the considerable PFS improvements were “consistent across all subgroups including number of prior therapies, presence of visceral disease, bone metastases, and prior use of chemotherapy.”

The majority of females with metastatic disease to not respond properly to initial hormonal therapy, and most of those who do respond at first tend to develop resistance, the presenters explained. Life expectancy is significantly reduced as the disease progresses.

There is a protein in cancer cells called mTOR which plays a key role in regulating tumor cell division, the growth of blood vessels that feed the tumor, and cell metabolism. Everolimus tagets mTOR. Experts say that hormonal therapy resistance in breast cancer has been linked to over-activation of the mTOR pathway.

BOLERO-2 data will be submitted to regulatory agencies around the world by the end of this year, Novartis informs.