Femara heralded as breakthrough in breast cancer

Compelling new evidence showing Novartis' Femara reduces the risk of breast cancer recurring in patients has been heralded as a breakthrough in treating the disease.

An international clinical trial of Femara (Letrozole) in post-menopausal survivors of early-stage breast cancer after completing a five year course of tamoxifen showed a significantly reduced risk of the cancer returning compared to women taking the placebo.

The results have been so significant the trial has been unblinded, allowing women taking the placebo to start taking Femara, one of the aromatase inhibitor class of cancer drugs.

No drug until now has demonstrated the ability to reduce the risk of recurrent breast cancer after five years of tamoxifen treatment, after which time tamoxifen has been shown to actually increase risks of endometrial cancer, pulmonary embolism and stroke. Researchers say that women will now have the option of taking Femara for a further five years.

"This is one of the most important advances in the treatment of postmenopausal women with breast cancer, and is a valuable step in preventing disease recurrence," said Professor Ian Smith, an investigator and Head of the Breast Unit at the Royal Marsden NHS Trust.

Letrozole has demonstrated its superiority to tamoxifen at treating advanced breast cancer and early breast cancer before surgery, and the researchers hoped the drug would benefit patients after surgery and five years of tamoxifen therapy for early breast cancer.

"The data revealed today surpassed our expectations with Letrozole more than doubling the improvement in disease-free survival and nearly halving the risk of breast cancer recurring or spreading to the other breast," added Professor Smith.

"We can now offer women who complete five years of tamoxifen therapy another drug which can reduce the risk of their cancer returning."

Novartis intend extending Femara's licence to allow doctors to prescribe the drug after five years of tamoxifen therapy. Femara is competing with two other aromastase inhibitors, AstraZeneca's Arimidex and Pfizer's Aromasin to become the natural successor to the current gold standard treatment tamoxifen. Cancer Research UK is now overseeing the British arm of an international phase III trial of Arimidex as a preventative measure in healthy post-menopausal women at high risk of developing breast cancer.

Commenting on the findings from the Femara study, Cancer Research Professor Jack Cuzick said: "The new findings are further evidence that aromatase inhibitors look like becoming the most effective hormone treatments for breast cancer in post-menopausal women."

In the UK, Arimidex is licensed only as an alternative to tamoxifen for the treatment of early breast cancer in women for whom tamoxifen is contraindicated, while Aromasin is licensed only for advanced breast cancer. Femara is licensed only as a pre-operative therapy to allow subsequent breast conserving surgery in women not originally considered candidates for the operation.

An extension to Arimidex's UK licence last November led Novartis to query the evidence for the decision. Data from AstraZeneca's phase III ATAC trial, comparing Arimidex to tamoxifen persuaded the UK and US authorities to extend the drug licence, even though it did not demonstrate improved chances of survival for patients.

Meanwhile, NICE recently took the unprecedented step of delaying its appraisal of the aromatase inhibitors by two years to await clinical trial results from the competing drugs.