Pfizer will get a rapid review at the US FDA for its new breast cancer candidate palbociclib, meaning it could be approved in the first quarter of 2015.
The FDA has said it will deliver a verdict on palbociclib – one of the most anticipated drugs in Pfizer’s pipeline with peak sales potential of $3bn-$4bn according to analysts – by April 13 next year.
Pfizer is seeking approval of palbociclib in combination with Novartis’ Femara (letrozole) as a first-line treatment for postmenopausal women with oestrogen receptor positive (ER+), HER2-negative advanced breast cancer who have not received previous systemic treatment.
Around 60% of breast cancer patients in the US have this receptor profile and could be eligible for treatment with palbociclib, a first-in-class cyclin-dependent kinase (CDK) 4 and 6 inhibitor that has been granted breakthrough status by the FDA.
The marketing application is based on final results from the phase II PALOMA-1 trial, which compared palbociclib plus Femara to Novartis’ drug alone in this patient group and showed that adding Pfizer’s drug to treatment doubled progression-free survival (PFS).
Results presented at the American Association of Cancer Research (AACR) meeting in San Diego in April showed that the median PFS in the combination treatment arm was 20.2 months, versus 10.2 months for patients administered Femara alone.
Overall survival was also improved by around four months with palbociclib (37.5 months versus 33.3 months), but this trend did not reach statistical significance.
Pfizer is also conducting two phase III studies of palbociclib in ER+, HER2- advanced/metastatic breast cancer which recently completed enrolment and also has a third trial looking at preventing recurrence in patients with early breast cancer.
The priority review status could also give Pfizer a big lead in the market over other drugs developing CDK4/6-targeting drugs for cancer, which include Novartis’ LEE011 (due to start phase III later this year) and Eli Lilly’s bemaciclib which recently cleared a phase I trial.
The pharma company is also collaborating with other companies on a number of combination studies with palbociclib. For instance, it is working with Merck & Co to combine the drug with PD-1 inhibitor pembrolizumab in breast cancer and melanoma, and with GlaxoSmithKline (GSK) to look at its role alongside melanoma drug Mekinist (trametinib).