‘New cancer drugs have not led to substantial increase in lifespans’
80% of targeted therapy drugs have extended lives by only 2 months, say expertsmumbai Updated: Feb 27, 2016 01:15 IST
Though about 300 billion dollars have been spent worldwide over the last 15 years on development of cancer drugs, the medicines have not increased the lifespans of cancer patients substantially, said cancer experts who attended the conference to mark the platinum jubilee of Tata Memorial Centre, India’s premier cancer treatment facility.
Doctors debated the efficiency of targeted therapy – the most recent form of cancer treatment where the medicine blocks the growth of the cell molecule - like proteins - responsible for the development of cancer. To support the argument, Dr Antonio Fojo from Columbia University said that 20% of the 96 drugs developed for targeted therapies have not improved the survival outcomes and the rest only increased lifespan by an average of two months. “More than medical, it is an ethical issue,” said Fojo to an audience of about 800 doctors gathered at a scientific conference organised to mark Tata Memorial Centre’s landmark.
Later, speaking to HT, Fojo said, “There are a lot of bad bets we have made. We (medical community and pharmaceutical companies) did pursue a lot of very poor targets. Majority of these therapies are not going to benefit the patient and in many it may cause more harm and some gain nothing at all.”
At present, most cancers are treated with a cocktail of treatment options which include surgery, chemotherapy and targeted therapy. The latest entrant to these fields of treatment is immunotherapy where a person’s own immunity is used to attack the cancerous cells.
Disagreeing with Fojo, Dr Amit Oza practicing oncology at Toronto, Canada said that targeted therapy is used exclusively to treat five to 10% of all known cancers and that it was too early to label the treatment as a failure.
“We are making the same mistake we made with chemotherapy years ago. We are practicing chemotherapy for 100 years and we are still refining it. It is only15 years that targeted therapy has started developing,” said Oza. In chemotherapy, cancer cells are killed by the drug unlike targeted therapy where the molecule responsible for developing cancer is blocked.
Dr Oza said that targeted therapy is beneficial for patients having chronic myeloid leukaemia-a cancer that starts in a person’s bone marrow. “It is transforming the way we are treating some forms of cancer. We need to give it some time and design the right studies and ask the right questions,” said Dr Oza adding that the key lies in customising treatment as every individual’s diseases is also individual.
Experts said that targeted therapy can be made more efficient if, instead of offering it all patients, efforts are made to identify those who will benefit the most. As most research related to drug development is funded by pharmaceutical companies which look more at finance than science, said experts.
The biggest challenge in cancer treatment is in convincing patients the limits medicines have in curing diseases. “Patients don’t want to die. If a patient is told that 95% of who receive treatment will not benefit, they will have an optimistic view and see themselves in the 5% who are likely to benefit out of the treatment,” said Fojo.