With the hammering they are taking in the courts over payouts to women who feel they were not warned of the dangers of HRT, Pfizer is being cautious, or sensible, depending on your point of view.
On 15 March, 2010 they announced that they have stopped a phase-III trial of their monoclonal antibody Figitumumab and two trials of Sunitinib in breast cancer after they failed to show significant improvement in survival rates.
Figitumumab targets the insulin growth factor-1 receptor (IGF-1R) pathway, which is thought to be one of the key signalling pathways leading to uncontrolled tumour growth.
Pfizer discontinued the trial that had Figitumumab in combination with Erlotinib against Erlotinib alone as a second or third-line treatment. Erlotinib is a small molecule drug that inhibits tyrosine kinase, an enzyme associated with the human Epidermal Growth Factor Receptor (EGFR). By inhibiting this enzyme, Erlotinib prevents EGFRs from stimulating the uncontrolled growth of cells that contributes to tumour growth. Erlotinib is FDA-approved as a treatment for patients with locally advanced or metastatic non-small cell lung cancer.
The company said that they found this particular drug combination seems unlikely to demonstrate a significant improvement in overall survival compared with using Erlotinib alone.
Nor is this the first time Pfizer have had to shut down a trial. They had to do so in December 2009 when a combination drug of Carboplatin and Paclitaxel was again shown not to improve survival rates.
The worrying part, for me, is that they are continuing with trials using Figitumumab for breast and prostate cancers. I know medical research can be hit and miss and I welcome the public statement of the discontinued trials as a sign that Pfizer are finally realising the impact of negative public opinion.