Evaluación del impacto de establecimiento de criterios de uso en la selección de medicamentos

Abstract

ABSTRACT The ongoing inclusion of new medications is a key factor explaining the increase in healthcare spending; however, new medications do not always result in better health outcomes, as very few actually offer significant advantages over existing therapies in terms of efficacy and safety. In the European Union, the procedure for authorizing the sale of new drugs does not require a comparison with standard treatments or include a review of a drug¿s cost- effectiveness. Drug used in hospitals are assessed and selected by Pharmacy and Therapeutics Committees. Of all the drugs assessed by Pharmacy and Therapeutics Committees, cancer drugs are particularly important because of their budgetary impact and the sometimes arguable added value with respect to existing alternatives, which is measured in terms of improved rates of survival or quality of life. OBJECTIVES The aims of this study were to evaluate the connection between the criteria for use and the outcomes in terms of health and economics of drugs selected by the Pharmacy and Therapeutics Committee .To assess the degree to which the cancer drugs included in the hospital¿s formulary were used in accordance with the criteria for use set out by the Pharmacy and Therapeutics Committee (compliance). To analyse the selection of new drugs by the Pharmacy and Therapeutics Committee of Cabueñes Hospital. MATERIALS AND METHODS Retrospective observational longitudinal study of a cohort of patients and drugs assessed by the Pharmacy and Therapeutics Committee. The study was carried out between 1 May 2007 and 30 April 2010. It included all patients who were treated with bevacizumab, cetuximab, trastuzumab and bortezomib and their use was assessed from the moment each one was approved by the Pharmacy and Therapeutics Committee, with a follow-up through 31 April 2011. In order to assess the degree to which prescriptions complied with the criteria for use stipulated by the Pharmacy and Therapeutics Committee, the real conditions under which each drug was being used were compared with the Pharmacy and Therapeutics Committee¿s criteria for use. Compliance was analysed based on a series of different variables for each drug: diagnosis, stage of the disease, life expectancy, treatment regimen, line of treatment, previous treatments, doses, frequency and number of cycles. For each of the four drugs and for each of the clinical indications, a score was calculated using previous criteria-for-use variables. Each criterion had the same weighting and ranged from 0 to 10. Clinical impact is assessed in terms of effectiveness, calculating in each drug-pathology the primary end point in the pivotal clinical trial, and security, listing the incidence of adverse reactions, the type and degree of toxicity. Costs are calculated for each drug evaluated, the medium cost per cycle and the medium cost of treatment per patient. The cost-effectiveness it is estimated. For each drug and pathology all these variables are compared between the group of patients who met all the criteria for use and those that did not comply. The following variables were collected in order to evaluate the Pharmacy and Therapeutics Committee¿s selection activities: number of drugs assessed/year, number of drugs included in any of these settings: without restrictions, with criteria for use and not included in formulary. These drugs where also analysed by therapeutic group. RESULTS Between May 2007 and April 2010, 272 patients in 293 episodes were included. For the two drugs where the sample was larger, bevacizumab in metastatic colorectal cancer and bevacizumab in non-small lung cell cancer, effectiveness was greater in patients who meet the criteria of use established by the Pharmacy and Therapeutics Committee than in those who do not comply. Adverse reactions appear in 87% of patients, but in none of the drugs evaluated were found statistically significant differences between the group of patients who met criteria for use and which failed. Only for bevacizumab in non-small cell lung cancer treatment of compliant patients were more economical, however the drugs were more cost-efficient in bevacizumab in lung cancer, bevacizumab colorectal cancer, and trastuzumab in early breast cancer. The Pharmacy and Therapeutics Committee received requests for inclusion of 40 drugs, of which 32 were included in the hospital formulary (80.0%). Criteria for use were established for 28 (87.5%) of the drugs included. 293 patients were treated with the 4 cancer drugs in 8 different therapeutic indications. The average prescription compliance scores were as follows: bevacizumab: 83% for metastatic colorectal cancer, 100% for metastatic breast cancer and 82.3% for non-small cell lung cancer; cetuximab: 62.0% for colorectal cancer and 50% for head and neck cancer; trastuzumab: 95.1% for early breast cancer and 82.4% for metastatic breast cancer; and bortezomib: 63.7% for multiple myeloma. CONCLUSIONS For bevacizumab in metastatic colorectal cancer and bevacizumab in non-small cell lung cancer, the ratio cost-effectiveness is lower in patients who meet the criteria for use set out by the Pharmacy and Therapeutics Committee, confirming the hypothesis that establishing criteria for use in the inclusion of new drugs reports clinical benefits in the patient and economic benefits for the institution. The degree of compliance with criteria for use of cancer drugs was high. Pharmacy and Therapeutic Committee functions need to be changed so that they carry out more innovative tasks such as monitoring conditions for drug use.