Key decisions must be taken urgently - by no later than end-March - to ensure a smooth changeover to the new system of pricing for drugs used by the NHS, the House of Commons Health Committee has said today.

The MPs are highly critical of the delay in setting out precisely what a value-based pricing (VBP) system for drugs will entail, reporting today on their recent inquiry into the work of the National Institute for Health and Clinical Excellence (NICE). Given that the government opened its consultation on the issue in December 2010, it is unacceptable that the arrangements for VBP have still not been settled and that those who will have to work with those arrangements are still unclear about what VBP will mean in practice, they say.

Industry, patient groups and clinicians all need clarity about how a new system will work and how they can make their views heard, say the MPs, who call for decisions to be taken no later than the end of March this year.

The Committee also notes that there is uncertainty about the implications of changes proposed for the Cancer Drugs Fund, which is set to be superseded by the VBP system. The panel is calling for: - an assessment of the outcomes for those patients whose treatment has been paid for by the Cancer Drugs Fund; - evidence of beneficial outcomes which should inform the new VBP scheme and applied to treatments for conditions other than cancer; and - clarity about how drugs which have been paid for by the Fund will continue to be available to individual patients.

The MPs' report also expresses concern about implications for the effectiveness of NICE of recent evidence about access to information from clinical trials. There needs to be both a professional and legal obligation to ensure that all regulators, including NICE, have access to all available research data about the efficacy and safety of drug products in use in the UK, and all information arising from trials concerning drugs that are in clinical use should be in the public domain, and in an accessible form, they say.

The Committee urges the pharmaceutical industry to introduce a new code of practice to make this commitment effective, and calls on the General Medical Council (GMC) to reiterate its guidance to doctors on the conduct of clinical trials.

It should be neither legal nor ethical to withhold research data about drug products which are in clinical use, say the MPs; the fact that this principle is not universally applied in practice undermines NICE's effectiveness. They welcome the current review of these issues by the House of Commons Science and Technology Committee, and call for that panel to examine the nature of both the legal and ethical principles which should cover these issues and how to make those principles enforceable in practice.

The Committee report emphasises the importance for the credibility of NICE that the patient voice is effectively and openly represented in all its work. It also recommends that NICE guidance should continue to be guidance rather than instruction and that the NHS should continue to allow local discretion and individual judgements by doctors and patients, but that variations from NICE guidance should be open, transparent and accountable.

Launching the report, Committee chair Stephen Dorrell MP said that what the panel had been told during its inquiry indicates that the move to VBP will be a more modest change than has been suggested. However, "there is a lack of clarity around the whole issue that has persisted for too long," he said.

"Decisions need to be taken, and the details of the scheme made public to avoid problems with the transition to the new system at the beginning of 2014. We hope the government will respond positively to our suggestion that this situation should be clarified before the end of March this year," he added.

Similarly, there needs to be a proper assessment of what benefits the Cancer Drugs Fund has brought, with those benefits being applied to the treatment of other conditions, as well as providing a clear mechanism for the future funding of treatment for patients whose drugs have been paid for from the Fund, said Mr Dorrell, who is Conservative MP for Charnwood.

The MPs are also concerned about the evidence they received that some of the data supplied from clinical trials has been selective and incomplete. "This situation cannot be allowed to continue, and we set out a number of practical steps that could be taken now to increase transparency about the results of clinical drug trials and which would benefit everyone - patients, clinicians and the pharmaceutical industry," he said.