Benefit of gefitinib limited to patient subgroup
Benefits of gefitinib (Iressa) as a second-line treatment for patients with non-small-cell lung cancer are limited to those of Asian origin and those who have never smoked, a post-marketing study published last month suggests (Lancet 2005;366:1527).
The phase III study, involving 1,692 patients, was designed to assess
the survival advantage of gefitinib, together with best supportive care,
in patients with advanced non-small-cell lung cancer who were refractory
to, or intolerant of, their more recent chemotherapy regimen. After 7.2
months of follow-up, median survival did not differ significantly between
patients treated with gefitinib and those given the placebo (hazard ratio
0.89, 95 per cent confidence interval 0.77–1.02; P=0.087).
However, subgroup analyses, planned before the study began, showed that
survival among patients of Asian origin and patients who had never smoked
was longer for those taking gefitinib than for those given placebo (median
survival was 9.5 months for patients of Asian origin, compared with 5.5
for non-Asians, and 8.9 months for patients who had never smoked, compared
with 6.1 for former or current smokers). Asian patients and never-smokers
also gained more benefit from gefitinib in time to treatment failure,
objective response rate, quality of life and improvement in disease-related
symptoms.
The researchers highlight methodological differences between their trial
and previous phase II trials demonstrating tumour shrinkage and survival
benefits, which may explain why they failed to find a survival benefit
for gefitinib. They also argue that prospective studies are needed to
clarify the relationship between underlying biology and response or survival. |
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