Cancer’s Magic Bullet

Br Dr Amarpreet S Dhiman, Research Analyst, Frost & Sullivan Healthcare Practice

A new magic bullet drug has been found to significantly boost survival hopes for patients with cancer. The drug, Tarceva, is a small molecule designed to target the human epidermal growth factor receptor 1 (HER1) pathway, which is one of the factors critical to cell growth in many cancers. HER1, also known as EGFR, is a key component of the HER signalling pathway, which plays a role in the formation and growth of numerous cancers. Tarceva is designed to inhibit the tyrosine kinase activity of the HER1 signaling pathway inside the cell, which may block tumour cell growth. Therefore, it is regarded as targeting a chemical that is critical to cell growth in many cancers. ACCORDING TO the World Health Organisation, there are more than 1.2 million cases worldwide of lung and bronchial cancer each year, causing approximately 1.1 million deaths annually. Non-small cell lung cancer (NSCLC) is the most common form of the disease and accounts for almost 80 per cent of all lung cancer cases. A recent study showed that Tarceva helped to extend survival of patients with NSCLC. Positive results were announced from a phase III study of Tarceva in relapsed NSCLC patients.

The study met its primary endpoint of improving overall survival with patients on Tarceva living longer than those in the placebo. The trial also met secondary endpoints including improving time to symptomatic deterioration, progression- free survival and response rate. Tarceva’s activity has not stopped there; it is being scheduled for use in clinical trials of other solid tumours, such as ovarian, colorectal, head and neck, kidney, brain and gastrointestinal cancers. One of the most deadly forms of cancer under trials is pancreatic cancer since it is widely recognised as a difficult disease to treat, and new therapeutic regimens are desperately needed. The pancreas is a large organ lying behind the stomach that is essential in the metabolism of sugar and fat. Pancreatic cancer affects 6,000 victims a year and is the fourth leading cause of all cancer deaths in Britain. Just five per cent of all sufferers are still alive five years after diagnosis. Those at the highest risk are in their 60s to 80s. Most pancreatic tumours originate in the cells of the pancreas that produce digestive enzymes (Acinar cells). These adenocarcinomas account for almost 95 per cent of pancreatic tumours. But now scientists have found a drug, which can increase life expectancy if taken alongside standard chemotherapy. The discovery offers vital hope to patients with the advanced form of the disease.

The study, which comprised sites in the U.S., Asia, Canada, Europe, Australia and South America, showed a 23.5 per cent improvement in overall survival for patients with locally advanced or metastatic pancreatic cancer receiving Tarceva as well as the chemotherapy drug Gemcitabine, compared with patients on Gemcitabine alone plus placebo. A hazard ratio of 0.81 and a p-value of 0.025 were observed (a hazard ratio of less than one indicates a reduction in the risk of death and a p-value of less than 0.05 indicates statistical significance). Median and one-year survival in the Tarceva plus Gemcitabine were 6.4 months and 25.6 per cent respectively compared to 5.9 months and 19.7 per cent in the Gemcitabine plus placebo. A statistically significant improvement in progression-free survival was also demonstrated, although no difference in tumour response was observed. A preliminary analysis of the safety data did not reveal any unexpected safety signal beyond that seen in prior use of Tarceva in both monotherapy and combination settings. Dr. Malcolm Moore, lead researcher of the Princess Margaret Hospital in Canada stated “The results so far represent “an important advancement in treating patients with pancreatic cancer”. Trials have been so successful that scientists are hopeful it will be available for use on patients within a couple of years.

Drugs giant Roche, which manufactures Tarceva, hails it as one of the new “magic bullet” drugs that work on cancer without harming other healthy cells and hopes it could also help to fight other forms of cancer. The Swiss healthcare group recently filed for EU marketing approval for its Tarceva drug to treat advanced NSCLC, boosting its shares. Within the last five years the Roche Group, including its partners Genentech in the U.S. and Chugai in Japan, has become the world’s leading provider of anticancer treatments, supportive care products and diagnostics. Analysts estimate that Tarceva, one of a new class of targeted therapies offering hope to cancer patients for whom more traditional treatments have failed, could generate annual sales of some $1.6 billion by 2009 for Roche and its partners.