Glaxo, Novartis drug combo delays breast cancer

LONDON (Reuters) - Combining GlaxoSmithKline's Tykerb drug with Novartis's Femara can delay significantly the progression of breast cancer in some women, researchers said on Thursday.

Persuading doctors to use Tykerb, known chemically as lapatinib, with Femara, or letrozole, could open up hundreds of millions of dollars in extra sales for Glaxo's drug, but the scale of any uplift hinges on just how many patients benefit.

A 1,286-patient study found a sub-set of women with aggressive HER2-positive metastatic breast cancer -- so called because the tumors overproduce a protein known as HER2 -- gained substantially from taking the two drugs together.

On average, the 219 patients studied in this category went 8.2 months before their disease progressed when given both drugs, while those on Femara alone had a median progression-free survival (PFS) of 3.0 months.

Femara is an established hormone-based drug for women with hormone receptor-positive cancer, while Tykerb is a newer medicine targeting HER2 and a second protein called EGFR.

Both drugs are given by mouth rather than injection.

However, when the combination was given to patients irrespective of HER2 status the benefit seen was only small, with PFS extended by just one month to a median 11.9 months.

Glaxo said the clinical results presented at the San Antonio Breast Cancer Symposium in Texas were positive and encouraging for women with hormone receptor- and HER2-positive tumors.

"We plan to discuss these data with regulators in the near future," said Paolo Paoletti, senior vice president for oncology research and development.

But whether there is sufficient evidence to convince oncologists to use both drugs across a wider population group, regardless of HER2 status, was unclear.

Tykerb -- a rival to Roche and Genentech's blockbuster injectable drug Herceptin -- is currently only a minor seller for Glaxo, with third-quarter revenue of just 26 million pounds ($38.8 million).

But the British-based company expects to ramp up sales substantially in the years ahead as the drug is used more widely and at an earlier stage in cancer.

($1=.6699 pounds)

(Editing by Greg Mahlich)