Iressa Receives TGA Approval

The Australian Therapeutic Goods Administration (TGA) has announced its approval of Iressa for the treatment of patients with locally advanced or metastatic non-small cell lung cancer (NSCLC) who have previously received chemotherapy. Gefitinib (IRESSA TM, ZD1839), produced by AstraZeneca, is the first in a new class of anti-cancer drugs known as Epidermal Growth Factor Receptor (EGFR) inhibitors. In Australia, lung cancer is the leading cause of cancer death in men, and is poised to overtake breast cancer as the leading cause of cancer death in women. Overall, lung cancer is responsible for more deaths than prostate cancer and breast cancer combined.

The outcome for lung cancer is poor. Overall, the five-year survival rate (the proportion of patients alive five years after diagnosis) for men and women respectively are 11% and 14%. Prognosis depends on how far the cancer has spread when it is first detected. If non-small cell lung cancer is found before it has spread to other organs, the five-year survival rate is about 50%. However, few lung cancers are found at this early stage due to absence of symptoms and it is normally diagnosed at the advanced stage, resulting in poor overall survival.Dr Mitchell said today that the targeted approach of Iressa offers patients with advanced lung cancer an important new treatment that could potentially shrink tumours, stabilise disease and relieve debilitating symptoms, without the toxic side effects of chemotherapy.’Targeted treatments are an exciting area of ongoing research as they hold the potential for more effective cancer therapy with minimal side effects,’ he said.’About 40 per cent of advanced non-small cell lung cancer patients who have previously had chemotherapy will benefit from Iressa in terms of improvement in their lung cancer symptoms, and avoid the side effects associated with chemotherapy.’ ‘And in up to 20 per cent of patients, their tumour will shrink.’One of the most important pathways involved in cancer cell growth is the epidermal growth factor receptor signalling system. Activation of this receptor triggers an enzyme inside the cell to start a cascade of chemical signals within the cell, which ultimately leads to the cancer cell dividing out of control. Dr Mitchell said that Iressa offered patients with advanced lung cancer the prospect of rapid relief of debilitating symptoms, enabling them to return to a more normal life.’The once-daily oral dose and rapid improvements in disease-related symptoms in about eight to 10 days – such as chest pain, shortness of breath and coughing – all provide important quality of life benefits to patients,’ he said.Associate Professor Michael Boyer, Head of the Department of Medical Oncology, Royal Prince Alfred Hospital, Sydney said until now only a select number of lung cancer patients were treated with a second line of chemotherapy after completing the first course.’The arrival of Iressa gives patients another choice of treatment after chemotherapy, with the potential for symptom improvement without the side effects of chemotherapy such as nausea and suppression of their immune system,’ Professor Boyer said.’For people with more advanced disease it is important for them to be informed of all the treatment options so they can make a decision about whether treatment is worthwhile or not.’There is already significant experience in Australia with Iressa as more than 400 patients have received the drug for advanced non-small cell lung cancer via clinical trials or under a compassionate use program at 50 registered sites in Australia.The approval of Iressa in Australia is based on two large, double blind, multicentre Phase II trials evaluating two oral doses of Iressa. These trials showed that once-a-day treatment with gefitinib produced clinically-significant anti-tumour activity in patients with previously treated advanced non-small cell lung cancer. Several Australian cancer centres were involved in one of these trials.Dr Paul Mitchell said up to 54 per cent of patients treated with Iressa – who had become unresponsive to conventional treatments available – experienced stabilisation of their disease (either tumour shrinkage or stable disease). ‘These responses were often associated with rapid relief (median time 8 to 10 days) of the debilitating symptoms associated with lung cancer,’ Dr Mitchell said.Iressa has just received approval this week from the United States Food and Drug Administration.