London, Oct 6 (IANS): Nearly half of new cancer drugs approved in Europe show little evidence that they are helping extend or improve life, says a new study.

Even where drugs did show survival gains over existing treatments, these were often marginal, found the researchers based at King's College London and the London School of Economics.

The study published in the journal BMJ prompts calls to "raise the evidence bar" for approval of new cancer drugs.

Many of the drugs were approved on the basis of indirect ('surrogate') measures that do not always reliably predict whether a patient will live longer or feel better, raising serious questions about the current standards of drug regulation.

"When expensive drugs that lack clinically meaningful benefits are approved and paid for within publicly funded healthcare systems, individual patients can be harmed, important societal resources wasted, and the delivery of equitable and affordable care undermined," the researchers said.

The team analysed reports on cancer approvals by the European Medicines Agency (EMA) from 2009 to 2013.

Of 68 cancer indications approved during this period, 57 per cent (39) came onto the market on the basis of a surrogate endpoint and without evidence that they extended survival or improved the quality of patients' lives.

Out of 68 cancer indications approved by the EMA, and with a median five years follow-up, only 35 (51 per cent) had shown a survival or quality of life gain over existing treatments or placebo.

For the remaining 33 (49 per cent), uncertainty remains over whether the drugs extend survival or improve quality of life.

Taken together, these facts paint a sobering picture, Vinay Prasad, Assistant Professor at Oregon Health & Science University in the US said in a linked editorial.

"The expense and toxicity of cancer drugs means we have an obligation to expose patients to treatment only when they can reasonably expect an improvement in survival or quality of life," he said.

These findings suggest "we may be falling far short of this important benchmark", according to Prasad.