Association between treatment effects on disease progression (DP) endpoints and overall survival (OS) in patients with metastatic renal cell carcinoma (mRCC)

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Background: Access to safe and effective novel therapies may be expedited if DP endpoints (progression-free survival [PFS], time to progression [TTP], or event-free survival) are established as valid surrogates for OS in pivotal studies in mRCC. While the association between DP endpoints and OS has been established in other cancers, it has not been rigorously examined in patients with mRCC. We assessed the association between treatment effects on DP endpoints and treatment effects on OS in controlled trials of patients with mRCC. Methods: A systematic literature search was conducted (Medline, conference abstracts, references of retrieved studies/ reviews) to identify studies meeting the following criteria: controlled trials in mRCC of IL-2, IFN-α, sunitinib, sorafenib, pazopanib, bevacizumab, temsirolimus, or everolimus; English language; publication date≥1997; median time to DP and OS reported for 2 or more treatment groups. For each treatment group comparison, we calculated the differences in median time to DP and median OS and analyzed the association between the differences in median time to DP and differences in median OS using weighted ordinary least-squares (OLS) regression. Results: A total of 21 studies representing 6182 patients, 52 treatment groups, and 35 comparisons were identified. The median difference between treatment groups in time to DP averaged 1.3 months; the median difference between treatment groups in OS averaged 2.8 months. The correlation between differences in median time to DP and differences in median OS was 0.69 (p < 0.0001). In weighted OLS regression, a 1 month difference in DP was associated with a 1.4 month difference in OS (p < 0.0001, adjusted R-sq = 0.46). Conclusions: In patients receiving treatment for mRCC, treatment effects on DP endpoints are predictive of treatment effects on OS.

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Economic analysis of basiliximab in renal transplantation

BACKGROUND

Basiliximab is a chimeric monoclonal directed against the alpha-chain of the interleukin-2 receptor. International studies have shown that it is highly effective in preventing acute rejection in patients receiving Neoral, and causes no measurable incremental toxicity, but its economic value remains unknown.

METHODS

This study employed an economic model to examine the potential economic benefit of basiliximab. Parameter estimates were derived from a randomized, prospective, double-blind study conducted in 21 renal transplant centers in seven countries in which 380 adult primary allograft recipients were randomized within center to receive basiliximab (20 mg i.v.) on days 0 and 4 or placebo in addition to dual immunosuppression with Neoral and steroids. Key clinical events included primary hospitalization, immunosuppressive drug use, patient and graft survival, graft rejection, treatment of rejection, dialysis, and repeat hospitalization. Health resources were valued via a comprehensive electronic cost dictionary, based upon a detailed economic evaluation of renal transplantation in Canada. Medication costs were calculated from hospital pharmacy acquisition costs; basiliximab was assessed a zero cost.

RESULTS

The average estimated cost per patient for the first year after transplant was $55,393 (Canadian dollars) for placebo and $50,839 for basiliximab, rising to $141,690 and $130,592, respectively, after 5 years. A principal component of the cost in both groups was accrued during the initial transplant hospitalization ($14,663 for standard therapy and $14,099 for basiliximab). An additional $15,852 and $14,130 was attributable to continued care, graft loss, and dialysis in the two groups, whereas follow-up hospitalization consumed an additional $15,538 for placebo and $13,916 for basiliximab. The mean incremental cost of dialysis was $5,397 for placebo compared with $3,821 for basiliximab, whereas incremental costs of graft loss were $2,548 compared with $2,295 in the two treatment groups. The principal costs associated with repeat admission to the transplant ward and the general ward were marginally higher for placebo ($7,395 vs. $6,300 and $5,986 vs. $4,625). Treatment of acute rejection and maintenance immunosuppressive drug use were associated with only limited savings as a result of basiliximab (savings <$200 each). Sensitivity analysis indicated that the most influential parameters affecting the savings as a result of using basiliximab were a reduction in the duration of initial and repeat hospitalization followed by the reduced risks of acute rejection and graft loss.

CONCLUSIONS

Before accounting for the cost of the therapy itself, basiliximab produces an estimated economic saving of $4,554 during the first year after transplant, of which $3,344 is attributable to the reduced costs of graft dysfunction, including graft loss and dialysis ($1,722) and follow-up hospitalizations ($1,622). When marketed, basiliximab is expected to cost approximately $3,000 per course (two doses of 20 mg), resulting in a net first-year saving of $1,554. Under these circumstances, basiliximab can be considered a dominant therapy in renal transplantation.

Rivastigmine for Alzheimer's disease: Canadian interpretation of intermediate outcome measures and cost implications

BACKGROUND

Clinical studies have shown that patients with Alzheimer's disease (AD) who are treated with rivastigmine have statistically significantly better scores on 5 scales used to assess AD than control patients receiving placebo. However, the clinical meaning and cost implications of these differences are not clear.

OBJECTIVE

The purpose of this study was to assess the clinical meaning and cost implications of statistically significant results obtained in clinical trials of rivastigmine for the treatment of AD. Potential cost implications for the health care system, caregivers, and society are considered.

METHODS

Data on clinical effects of rivastigmine were obtained from published North American and European clinical studies of patients with mild to moderately severe AD receiving rivastigmine 6 to 12 mg/d (n = 828) or placebo (n = 647). Differences in scores on the Alzheimer's Disease Assessment Scale-Cognitive Function, Clinician's Interview-Based Impression of Change with both clinical and caregiver information considered, Progressive Deterioration Scale, Mini-Mental State Examination (MMSE), and Global Deterioration Scale were assessed. A convenience panel of 9 Canadian specialists experienced in the treatment of AD provided their opinions on the clinical importance of the trial results. Chart review was performed to identify specific behaviors that improved, and cost implications of improvements were assessed.

RESULTS

The panel determined that statistically significant differences in scores on all scales except the MMSE were likely associated with functional or cognitive differences that were clinically relevant for patients, reflecting stabilization that would have beneficial consequences for caregivers and health care resource use. Subsequent chart review showed that improvement on specific scale items confirmed the physician panel's opinion. Analysis of possible cost implications to society indicated that medication expenditures would be offset largely by delays in the need for paid home care and institutionalization, positive effects on caregiver health, and less time lost from work for the caregiver.

CONCLUSIONS

From the perspective of a Canadian specialist panel, rivastigmine treatment for AD produces clinically relevant effects for patients that are beneficial to caregivers. These effects suggest decreased use of caregiver resources and delays in the need for institutionalization, both of which reduce societal costs.

The revised Canadian Guidelines for the Economic Evaluation of Pharmaceuticals

The first edition of the Guidelines for Economic Evaluation of Pharmaceuticals: Canada was published in November 1994. At that time, the Canadian Coordinating Office for Health Technology Assessment (CCOHTA) was assigned the task of maintaining and regularly updating the Canadian Guidelines. Since their introduction, a great deal of experience has been gained with the practical application of the guidelines. Their role has also evolved over time, from being a framework for pharmacoeconomic research to the point where a wide variety of decision-makers use economic evaluations based on the principles set out in the guidelines as a means of facilitating their formulary decisions. In addition, methodologies in certain areas (and the body of related research literature in general) have developed considerably over time. Given these changes in the science and the experience gained, CCOHTA convened a multi-disciplinary committee to address the need for revisions to the guidelines. The underlying principles of the review process were to keep the guidance nature of the document, to focus on the needs of 'doers' (so as to meet the information needs of 'users') and to provide information and advice in areas of controversy, with sound direction in areas of general agreement. The purpose of this review is three-fold: (i) to outline the process which lead to the revision of the Canadian Guidelines; (ii) to describe the major changes made to the second edition of this document; and (iii) to consider the 'next steps' as they relate to the impact of such guidelines and the measurement of outcomes related to economic assessments of pharmaceuticals in general.

Use of economic evaluation guidelines: 2 years' experience in Canada

Considerable effort has been expended in recent years in the development of methodology guidelines for economic evaluation of pharmaceutical products, driven in part by the desire to improve the rigour and quality of economic evaluations and to help decision making. Canada was one of the first countries to develop such guidelines and to encourage their use. This paper examines the extent to which the economic evaluations that were submitted to the Canadian Coordinating Office for Health Technology Assessment in the last two years adhered to Canadian guidelines. The analytic technique employed by twelve studies as well as the comparator used, the perspective taken, the outcome measure selected, the cost items that were taken into consideration and the extent of sensitivity analyses that were performed are reviewed in this paper. It can be concluded that although studies have been of variable quality, the majority of them were well presented, complete and transparent, due in part to the guidelines. Except for the perspective of the analysis, guidelines were, in many respects, adhered to and did not restrict investigators to specific methodologies or specific techniques. They were also instrumental in ensuring a minimum set of standards.

Biases in cost measurement for economic evaluation studies in health care

This paper addresses the issue of biases in cost measures which used in economic evaluation studies. The basic measure of hospital costs which is used by most investigators is unit cost. Focusing on this measure, a set of criteria which the basic measures must fulfil in order to approximate the marginal cost (MC) of a service for the relevant product, in the representative site, was identified. Then four distinct biases--a scale bias, a case mix bias, a methods bias and a site selection bias--each of which reflects the divergence of the unit cost measure from the desired MC measure, were identified. Measures are proposed for several of these biases and it is suggested how they can be corrected.

An economic evaluation of finasteride for treatment of benign prostatic hyperplasia

This evaluation was conducted at the request of a Canadian provincial government considering finasteride for formulary inclusion. The comparator therapies, in accordance with Canadian pharmacoeconomic guidelines, were the most prevalent treatment [transurethral resection of the prostate (TURP)] and the lowest cost treatment (watchful waiting). All costs were measured in 1994 Canadian dollars ($Can), and both costs and outcomes were discounted at 5% per annum. Cost-effectiveness and cost-utility ratios were calculated, and were found to be dependent on initial symptom severity and the anticipated duration of treatment with finasteride. The drug was shown to be the dominant alternative compared with both TURP and watchful waiting for patients with moderate symptoms, when the duration of drug therapy is 3 years or less. However, finasteride is a weak alternative for patients with severe symptoms who are treated for 4 years or more. For other groups of patients (i.e. moderate symptoms and on finasteride for 4 years or more; severe symptoms and on treatment for 3 years or less), the drug can improve health-related quality of life, but at a cost of between $Can3000 and $Can97,000 per incremental quality-adjusted life year (1994 dollars). Our study also indicated that it would cost between $Can2.7 million and $Can5.6 million, depending on the severity mix of the patients, to treat cohort of 10,000 men aged 60 years or older with finasteride.

A comparative review of pharmacoeconomic guidelines

We have reviewed 4 international sets of guidelines for the economic evaluation of pharmaceutical products-those of the Australian Pharmaceutical Benefits Advisory Committee, the Canadian Coordinating Office for Health Technology Assessment, the Ontario Ministry of Health, and the England and Wales Department of Health. Comparison of these guidelines reveals that there are a number of differences between them, including disparities in outcome selection, costs and perspectives. These observations were attributed to differences in study purpose, conceptual approach, measurement techniques and value judgements. Uniformity can be achieved only in conceptual approach and measurement technique. Guidelines should be flexible to accommodate differences in the study purposes and value judgements of the analysts.