Pfizer files for FDA approval of palbociclib in advanced breast cancer

Pfizer announced the completion Monday of its FDA filing seeking approval of palbociclib, in combination with Novartis' Femara (letrozole), for postmenopausal women with oestrogen receptor positive (ER+), HER2-negative advanced breast cancer who have not received previous systemic treatment for their disease. The drugmaker disclosed plans in May to submit the experimental inhibitor of cyclin-dependent kinases 4 and 6 for US regulatory approval.

The submission for the oral drug is based on final results from the mid-stage PALOMA-1 study. The drugmaker said the combination therapy met the primary endpoint of improved progression-free survival (PFS) over Femara alone. Specifically, median PFS in the combination treatment arm was 20.2 months, versus 10.2 months for patients administered Femara alone.

Palbociclib received FDA breakthrough therapy status last year based on interim PALOMA-1 data for the first-line systemic treatment of women with advanced or metastatic ER+, HER2- breast cancer. Pfizer indicated that it is also testing palbociclib plus Femara, versus Femara monotherapy, in the Phase III PALOMA-2 study involving the same patient population, while the late-stage PALOMA-3 trial is evaluating palbociclib in combination with AstraZeneca's Faslodex (fulvestrant), compared with Faslodex alone, in women with hormone receptor-positive, HER2- metastatic breast cancer whose disease progressed after prior endocrine therapy.

For related analysis, see ViewPoints: 'We have a pipeline too'...Pfizer confirms early US filing for blockbuster breast cancer hopeful.

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