Shares in Roche and Genentech have slipped after late-stage data from a trial of their oncology agent Avastin showed that both the standard dose and a lower dose of the drug, in combination with chemotherapy, improved progression-free survival in patients with non-small-cell lung cancer.

In the Phase III AVAiL trial, more than 1,000 patients with previously untreated advanced non-squamous NSCLC received either the standard 15mg/kg dose of Avastin (bevacizumab) or a 7.5mg/kg dose in addition to chemotherapy, or chemotherapy alone. The data revealed that both doses of the drug, plus chemotherapy, significantly prolonged progression-free survival, compared to chemotherapy alone and the companies noted that while the study was not designed to compare the two Avastin treatment doses, a similar treatment effect in progression-free survival was observed.

The shares in the two firms have fallen because analysts have picked up on the fact that the success of the low dose arm of the study will lead doctors to use the lower, and therefore less expensive, dose in the majority of lung cancer patients. However, it is also being suggested that any sales impact of the lower dose will be offset by increased use of the drug overall.

Avastin may extend survival in brain tumour patients

This news comes on the back of another study which suggests that Avastin can slow the growth of certain types of brain cancer. A pilot study conducted at Duke University Medical Center has tested the effectiveness of the drug in conjunction with a standard chemotherapy agent in patients with recurrent cancerous brain tumours called gliomas.

The researchers found that the two drugs together halted tumour growth up to twice as long as comparative therapies. Although gliomas remain incurable in nearly all cases, “the combined drug therapy may buy precious time and preserve physical and mental function longer for patients facing this grim diagnosis,” the researchers said.

"These results are exciting because of the possible implications for a patient population that currently has the poorest possible prognosis going into treatment, those with malignant brain tumours that have recurred after initial treatment," said Dr James Vredenburgh, lead researcher on the study, the findings of which are in the Clinical Cancer Research journal.