Astrazeneca's Iressa shows promise in non-small cell lung cancer

Preliminary data from the first pivotal Phase II trial of AstraZeneca'stargeted cancer drug Iressa (ZD1839) indicate that, when used as a second- or third-line treatment, it can achieve disease control in more than 50% of unselected patients with advanced non-small cell lung cancer who are refractory to prior platinum therapy.

Iressa is an orally-active agent that targets the epidermal growth factor receptor tyrosine kinase-mediated secondary messenger system and is among a new-generation of anticancer drugs, headed by Novartis' Glivec/ Gleevec (imatinib) for chronic myeloid leukemia, that are designed to address the underlying mechanisms behind tumor cell growth and leave healthy cells unscathed. Iressa's target is similar to that of antibody-based drug Erbitux (IMC-225) from ImClone and Bristol-Myers Squibb, which is being developed in the first instance for colorectal cancer (see adjacent story).

In the Iressa study, an overall tumor response rate of 18.7% was seen in the 210-patient study, which enrolled individuals who had not been selected for EGFR status. Two doses of Iressa were administered (250mg and 500mg/day), and the overall disease control rate was 52.9%, including 34% of patients who remained progression-free after four months. The median time to an improvement in disease-related symptoms was eight days, according to AstraZeneca, which noted that this level of efficacy was remarkable given the hard-to-treat patient population.