Phase III Data on PFE's Bosutinib - Analyst Blog

Pfizer Inc. (PFE) recently presented data on its chronic myeloid leukemia (CML) candidate, bosutinib. Results from an ongoing phase III study (BELA - Bosutinib Efficacy and safety in chronic myeloid LeukemiA) showed that bosutinib failed to achieve the primary endpoint of superior complete cytogenetic response (CCyR).

However, the candidate achieved a secondary endpoint in the study that was conducted in newly diagnosed patients with chronic phase Philadelphia chromosome positive (Ph+) CML. Results showed that a significantly higher proportion of patients in the bosutinib arm (39%) achieved a major molecular response (MMR) compared with patients treated with Novartis' (NVS) Gleevec (26%).

Fewer patients (1.6% versus 4%) in the bosutinib arm progressed to an advanced stage of the disease. While the death rate was lower in the bosutinib arm (1.2% versus 3.2%), the rate of serious adverse events was higher in the bosutinib arm (25.4% versus 13.5%) compared to the Gleevec arm.

Bosutinib is currently in another study that is being conducted in patients with previously treated chronic phase CML.

Earlier this week, Pfizer had announced that it intends to go ahead with its plans to file for the approval of bosutinib. The company said that it has started preparing for the filing of a marketing authorization application (MAA) with the European Medicine Agency (EMA).

Pfizer said that it intends to seek EU approval for the use of bosutinib in the treatment of patients with newly diagnosed Ph+ CML. As far as the US filing is concerned, Pfizer is looking to seek US Food and Drug Administration (FDA) approval for bosutinib for the treatment of previously treated Ph + CML patients. The US filing will be based on safety and efficacy data from a study that was conducted with patients resistant or intolerant to Gleevec, as well as patients not responding to Bristol-Myers Squibb's (BMY) Sprycel or Novartis' Tasigna.

Pfizer is currently in discussions with the regulatory agencies. The filings could take place in 2011.

CML is one of the four main types of leukemia. According to the National Cancer Institute, CML accounts for 15% of all leukemia worldwide. With no products available for CML patients who fail second-line treatment with Sprycel or Tasigna, Pfizer is looking to fill the gap with bosutinib.

Neutral on Pfizer

We currently have a 'Neutral' recommendation on Pfizer, which is supported by a Zacks #3 Rank (short-term “Hold” recommendation). While Wyeth brings with it an attractive biologics platform and some complementary products and businesses, we do not believe they are enough to sustain long-term top line growth. We see the merger as mostly an opportunity for Pfizer to cut additional costs. Longer term growth will be dependent on the success of drug development. Pfizer's recent track record with pipeline development has been poor.

The Lipitor patent expiration in 2011 remains a big concern. Lipitor contributed almost 23% to the top-line in 2009 with sales coming in at $11.4 billion. The entry of generic versions of the product will have a significant impact on the company's financials. The loss of patent exclusivity over the coming years will make it challenging for the company to drive top line growth.

 
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