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Iressa added to ASCO Clinical Practice Guidelines

WILMINGTON, DEL., February 2, 2004 -- An expert panel of the American Society of Clinical Oncology (ASCO) has updated the society's Clinical Practice Guidelines for the treatment of non-small-cell lung cancer. For the first time the panel has recommended Iressa (gefitinib) for the treatment of patients with locally advanced or metastatic non-small-cell lung cancer (NSCLC) after failure of both platinum-based and docetaxel chemotherapies.

The new guidelines were recently provided to the society's membership and published in the Journal of Clinical Oncology. Iressa is the first treatment for NSCLC other than surgery, radiation or chemotherapy to be included in the ASCO guidelines.
The ASCO guidelines also state that while the FDA indication allows Iressa to be used for any patient with NSCLC who is intolerant of or resistant to both platinum-based and docetaxel chemotherapy, preliminary data suggest that the population best suited for treatment with Iressa remains to be defined, and that similar to other chemotherapies used as salvage therapy, benefits may only be seen in a small percentage of patients.

The FDA approved Iressa in May 2003, based upon data from a U.S. Phase II trial that studied two doses of Iressa in a total of 216 patients who received both platinum-based and docetaxel chemotherapies. Included in the FDA analysis were 142 of the 216 patients. In the group receiving the recommended dose of 250 mg/day, 13.6% (95% CI: 6.4-24.3) of the patients had their tumor shrink by at least 50%. Higher doses did not give a better response and more side effects were observed. The overall response rate for both doses combined in all 142 patients was 10.6% (95% CI: 6.0-16.8). Median duration of response was 7 months (range 4.4 to 18.6+ months). The response rates appeared to be highly variable in subgroups of the treated population (gender, smoking history and histology) varying from 4.6-29.4%.

Iressa is approved in the United States for use as monotherapy for the treatment of patients with locally advanced or metastatic non-small-cell lung cancer (NSCLC) after failure of both platinum-based and docetaxel chemotherapies. The effectiveness of Iressa is based on objective response rates. There are no controlled trials demonstrating a clinical benefit, such as improvement in disease-related symptoms or increased survival. Results from two large (N = 2,130), controlled, randomized trials in first-line treatment of NSCLC (INTACT 1 & 2) showed no benefit from adding Iressa to a doublet, platinum-based chemotherapy. Therefore, Iressa is not indicated for use in this setting.

The most frequent drug-related adverse events associated with Iressa were diarrhea (48%) sometimes associated with dehydration, rash (43%), acne (25%), dry skin (13%), nausea (13%), and vomiting (12%). These events generally occurred within the first month of therapy and usually were mild to moderate. 2% of patients stopped taking Iressa due to an adverse drug reaction. Infrequent cases (about 1%) of interstitial lung disease (ILD-described as interstitial pneumonia, pneumonitis, and alveolitis) have been observed in patients receiving Iressa. Approximately 1/3 of the ILD cases were fatal. When ILD occurred, it was often accompanied by acute onset of breathing difficulty with cough or low-grade fever requiring hospitalization. The reported incidences of ILD in the 23,000 patient US expanded access program was about 0.3%. In Japanese post-marketing experience the reported rate of ILD was about 2%. In the phase III controlled studies in combination with chemotherapy, there were similar rates of ILD (about 1%) reported in both the placebo and Iressa arms of the study. Iressa may cause fetal harm if administered to a pregnant woman. Asymptomatic increases in liver enzymes and eye irritation have also been observed in patients receiving Iressa. Increases in bleeding events have been observed in cancer patients taking warfarin and Iressa.

Source: AstraZeneca

Posted: February 2004

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