New data showing an experimental AstraZeneca lung cancer drug shrank tumours in more than half of patients gives the British group fresh ammunition to argue that Pfizer's takeover offer undervalues it substantially.
Britain's second-biggest drugmaker has rejected a $106 billion approach from its US rival Pfizer, arguing that it has a bright future as an independent firm due to a promising pipeline of cancer and other drugs.
Its new lung cancer drug, known as AZD9291, targets a genetic mutation that helps tumours evade current treatments. AstraZeneca believes it could sell as much as $3 billion a year.
Results from an early-stage Phase I trial of the drug, released late on Wednesday, showed AZD9291 shrank tumors in 51% of patients. Tumours shrank in 64% of patients found to have the mutation, known as T790M, which develops in about half of lung cancers that become resistant to drugs known as epidermal growth factor receptor (EGFR) inhibitors.
Savvas Neophytou, an analyst at brokerage Panmure Gordon, said the results were impressive and “AstraZeneca's management is right to be excited by the pipeline”. AstraZeneca shares were 0.5% higher in a flat London market by 7:45 am GMT.
EGFR drugs, such as Roche's Tarceva and AstraZeneca's own Iressa, are used to treat various solid tumor cancers with mutated or overactive EGFR. Around 15% of patients with non-small cell lung cancer, the most common form of the disease, have mutations in the EGFR gene.
But most of them will eventually become resistant to available EGFR inhibitors, said Dr Pasi Janne, professor of medicine at Dana-Farber Cancer Institute and Harvard Medical School in Boston and the study's lead investigator.
AZD9291 is one of several new drugs flagged by AstraZeneca last week in a bid to convince investors of the strength of its experimental pipeline.
Chief executive Pascal Soriot told Reuters that data presented at this year's annual ASCO meeting would demonstrate how AstraZeneca was developing new therapy regimens that would change the way cancer was treated.
The British company forecasts that peak annual sales of the cancer drug could reach $3 billion, which is more than the $1 billion to $2 billion currently predicted by analysts.
The Phase I trial, featured ahead of the meeting of ASCO later this month, involved 199 patients with advanced non-small cell lung cancer with EGFR mutations whose disease worsened despite treatment with a current EGFR inhibitor.
The most common side effects seen in the trial included diarrhea and rash, but researchers said