Approval in US for Pfizer's renal cancer drug Inlyta

The US Food and Drug Administration (FDA) has approved Pfizer's Inlyta as a second-line treatment for patients with advanced renal cell carcinoma (RCC), a form of kidney cancer.

On the same day, the FDA also started its review of Pfizer's bosutinib for patients with previously-treated Philadelphia chromosome positive chronic myeloid leukaemia (CML).

The go-ahead for Inlyta comes after an FDA advisory panel gave its unanimous backing to Inlyta (axitinib) in this setting, despite earlier reservations by FDA reviewers about the patient population used in the pivotal trial filed in support of Pfizer's marketing application for the drug.

Pfizer said that Inlyta is the "first treatment to demonstrate superior benefit in a phase III study compared with another targeted agent in advanced RCC".

The approval is based on the results of a single efficacy study (AXIS) in 723 patients, which compared Pfizer's drug to Bayer's Nexavar (sorafenib). In that study Inlyta treatment significantly extended progression-free survival compared to Nexavar by two months to a median of 6.7 months.

Analysts have said they believe the drug could achieve sales of $500m within the next three years and more than $1bn at peak.

RCC is the most common form of kidney cancer, and five-year survival rates remain low at around 20 per cent, despite a series of new drugs entering the market in recent years.

Pfizer already markets one drug for RCC called Sutent (sunitinib) which achieved sales of $870m in the first nine months of 2011. Nexavar added €520m ($688m) to Bayer's coffers over the same period.

"Even with the advent of targeted therapies, the need remains for additional options for patients with advanced RCC whose disease has progressed following first-line medications," said Dr Mace Rothenberg, senior vice president of clinical development and medical affairs at Pfizer.

Meanwhile, the FDA's decision to accept Pfizer's dual tyrosine kinase inhibitor bosutinib dossier for review means the prospect of another line of treatment for CML patients.

According to Pfizer, there are no approved therapies beyond second-line treatments Sprycel (dasatinib), from Bristol-Myers Squibb, or Novartis' Tasigna (nilotinib).

In contrast to current first-line CML treatments such as Novartis' Glivec/Gleevec (imatinib), bosutinib inhibits both Abl and Src kinases and so may retain activity in CML patients who have developed resistance to therapy as a result of overexpression of Src kinases.