In the United States, new pharmaceutical products must be approved by the Food and Drug Administration (FDA) as being both safe and effective. This process generally involves submission of an Investigational New Drug filing with sufficient pre-clinical data to support proceeding with human trials. Following IND approval, three phases of progressively larger human clinical trials may be conducted. Phase I generally studies toxicity using healthy volunteers. Phase II can include pharmacokinetics and dosing in patients, and Phase III is a very large study of efficacy in the intended patient population. Following the successful completion of phase III testing, a New Drug Application is submitted to the FDA. The FDA review the data and if the product is seen as having a positive benefit-risk assessment, approval to market the product in the US is granted.
A fourth phase of post-approval surveillance is also often required due to the fact that even the largest clinical trials cannot effectively predict the prevalence of rare side-effects. Postmarketing surveillance ensures that after marketing the safety of a drug is monitored closely. In certain instances, its indication may need to be limited to particular patient groups, and in others the substance is withdrawn from the market completely.
The FDA provides information about approved drugs at the Orange Book site.
In the UK, the Medicines and Healthcare Products Regulatory Agency approves drugs for use, though the evaluation is done by the European Medicines Agency, an agency of the European Union based in London. Normally an approval in the UK and other European countries comes later than one in the USA. Then it is the National Institute for Health and Care Excellence (NICE), for England and Wales, who decides if and how the National Health Service (NHS) will allow (in the sense of paying for) their use. The British National Formulary is the core guide for pharmacists and clinicians.
In many non-US western countries a 'fourth hurdle' of cost effectiveness analysis has developed before new technologies can be provided. This focuses on the efficiency (in terms of the cost per QALY) of the technologies in question rather than their efficacy. In England and Wales NICE decides whether and in what circumstances drugs and technologies will be made available by the NHS, whilst similar arrangements exist with the Scottish Medicines Consortium in Scotland, and the Pharmaceutical Benefits Advisory Committee in Australia. A product must pass the threshold for cost-effectiveness if it is to be approved. Treatments must represent 'value for money' and a net benefit to society.
There are special rules for certain rare diseases ("orphan diseases") in several major drug regulatory territories. For example, diseases involving fewer than 200,000 patients in the United States, or larger populations in certain circumstances are subject to the Orphan Drug Act. Because medical research and development of drugs to treat such diseases is financially disadvantageous, companies that do so are rewarded with tax reductions, fee waivers, and market exclusivity on that drug for a limited time (seven years), regardless of whether the drug is protected by patents.