The fund was set up in 2010 to improve access to cancer drugs that are not routinely available on the NHS and was initially expected to run until March 2014, with a total budget of £650m. In 2013, the government extended the fund until March 2016 and it now has a total lifetime budget of £1.27bn.
Publishing the findings from its investigation into the fund, the National Audit Office said NHS England spent £416m on the fund in 2014/15, 48% more than planned.
Due to a lack of data, the NAO said it was not possible to evaluate the impact the fund has had on patient outcomes such as survival.
In March, NHS England took action to control the rapid growth in the cost of the fund, including removing drugs on the grounds of cost for the first time. It estimated this action would save £80m over the next year, but actual savings are likely to be lower and overall the fund will be £70m over budget in 2015/16.
NHS England proposed this month that it would to remove more drugs from the national list to save more money.
The NAO stated that “the fund is not sustainable in its current form,” and NHS England should develop proposals for reform.
NHS England has proposed that the fund become a “managed access” fund that pays new drugs for a set period before the National Institute for Health and Care Excellence decides whether the drugs should be routinely available on the NHS.
This means that the fund would no longer support the provision of drugs that have been appraised but not recommended by NICE.
NHS England plans to consult on its proposals in autumn 2015, with the aim of implementing the new arrangements from April 2016, the NAO said.
Public Accounts Committee chair Meg Hillier said there needed to be much better control of costs and proper assessments of whether these drugs are making a difference to the health of patients.
“Neither the Department of Health nor NHS England knows what impact the Cancer Drugs Fund has had in extending the lives of the patients treated,” she said.
“Given the need to make informed choices about how to spend finite resources wisely, it makes no sense that the department and NHS England lack the data needed to assess the effectiveness of the Cancer Drugs Fund and whether it is the best way to care for patients.”
In response to the report, a Department of Health spokeswoman said: "We want to lead the world in fighting cancer. Survival rates have never been higher, but we need to go further.
"So we are absolutely committed to the Cancer Drugs Fund which has already helped more than 72,000 people access drugs. This government is increasing the NHS budget as part of our long term economic plan – which allows important initiatives like the Cancer Drugs Fund to exist."