How Should Functionally Equivalent Drugs be Reimbursed?

Statutory reimbursement agencies as well as private insurers throughout member states of the Organization for Economic Cooperation and Development (OECD) reimburse the cost of medicines on the basis of criteria that include robust clinical evidence, budget impact analysis, and incremental cost effectiveness. The Centers for Medicare and Medicaid Services (CMS) in the US are no exception to this rule and are, in principle, seeking to maximize benefit for their Medicare enrollees, whilst ensuring reasonable drug outlays for the small number of drugs that they reimburse. This paper provides a retrospective analysis of the way two functionally equivalent drugs are treated for reimbursement purposes by the CMS; the period under consideration was 2001–3. The two drugs, epoetin-α and darbepoetin-α, are used for the treatment of anemia in renal failure and in patients receiving chemotherapy. By reviewing the publicly available pharmacological and clinical data of epoetin-α and darbepoetin-α, the paper confirms the two drugs’ functional equivalence, despite their structural differences. The implications of dose conversion ratios and costs to Medicare are subsequently explored. It is argued that the issue of dose equivalence between epoetin-α and darbepoetin-α has significant implications for patients, practitioners, and payors. A payor’s perspective is adopted in this respect, whereby clinical evidence and pricing data are used simultaneously. Based on the clinical evidence, a dose conversion ratio for epoetin-α:darbepoetin-α is established, which achieves a comparable clinical effect for the two drugs and this is set to be <254IU:1μg. The incremental costs to Medicare are calculated subsequently. The Average Wholesale Price and the Outpatient Prospective Payment System rule that Medicare uses to reimburse providers are used and suggest that treatment of cancer patients with chemotherapy-related anemia with epoetin-α would save Medicare an estimated $US600 million each year. Patients would also benefit significantly in terms of lower co-payments for epoetin-α. The evidence is supportive of the decision made by the CMS to reimburse the two drugs at the rate reflecting the achievement of comparable clinical effects and therefore reducing the pass-through payments for darbepoetin-α to zero for the 2002–3 fiscal year.     

Liver histology, blood biochemistry and RNA, DNA and subcellular protein composition of various skeletal muscles of rats with experimental cirrhosis: implications for alcoholic muscle disease.

(1) Liver cirrhosis was induced in male rats by treatment with carbon tetrachloride and phenobarbitone for 130-142 days. Detailed histological examination showed all livers from rats treated with carbon tetrachloride had annular fibrosis, necrosis, loss of normal hepatic architecture and other features that were consistent with an established micronodular cirrhosis. (2) Plasma biochemical analysis showed a significant reduction in total protein concentration (13%), which was due entirely to a reduction in plasma albumin (29%). There were also large increases in the plasma activities of alkaline phosphatase (110%) and aspartate aminotransferase (159%), when compared to phenobarbitone-treated controls. Plasma cholesterol was also increased (67%), but other plasma analytes were not significantly altered. (3) The soleus (Type I), plantaris (Type II) and gastrocnemius (Types I and II) muscles were dissected and examined for possible differential effects. There were minor reductions in all three muscle weights, but these changes did not reach statistical significance. The protein, RNA and DNA concentrations, total muscle content and content relative to body weight in cirrhotic rats were also not significantly altered in any of the muscles. Cirrhosis did not cause any perturbations in derived parameters, i.e. amount of synthetic apparatus per cell, RNA/DNA ratio, apparent cell size, protein/DNA ratio and the capacity for protein synthesis or RNA/protein ratio. (4) The gastrocnemius was fractionated into soluble, stromal and myofibrillar proteins. The concentrations and contents of all three proteins were unaltered in cirrhotic animals, compared to controls. (5) It is concluded that in this experimental model of cirrhosis there were no effects on those skeletal muscle variables which are strikingly altered by chronic alcohol feeding.(ABSTRACT TRUNCATED AT 250 WORDS)     

The path to care in autism: Is it better now?

Parents of children with autism often report problems associated with obtaining a diagnosis of their child's condition, family support, information, and appropriate services. To evaluate any changes in the situation over the last two decades, the families of all members of the West Midlands Autistic Society, age 19 years and below, were asked to fill in a questionnaire that covered aspects of detection, diagnosis, help and information received, and educational provision. Responses were obtained from 127 families, the children of whom formed an older group ages 10 years and above (n=67) and a younger group ages 9 years and below (n=61). Findings show that there have been improvements for the younger group in some areas, such as earlier referral, diagnosis, and statementing. However, the situation with respect to advice given by professionals and the support and provision available after referral is still much the same as that experienced by families of the older group of children. Many difficulties and hurdles remain which hinder parents and children on the path to care in autism.     

Late left ventricular diastolic flow propagation velocity determined by color M-mode Doppler in the assessment of diastolic dysfunction.

BACKGROUND: Early color M-mode Doppler flow propagation (Ep) through the left ventricle (LV) has been proposed as a useful noninvasive index for assessing LV relaxation, whereas data concerning late velocity propagation (Ap) is lacking. METHODS: We studied 51 patients with delayed relaxation (group I) and 50 with pseudonormal filling pattern (group II). Another 51 aged-matched healthy persons served as the control group. RESULTS: Patients showed increased left atrial dimensions, atrial wave of the pulmonary vein flow, and Ap, and reduced LV ejection fraction, Ep, and Ep/Ap ratio compared with the control group. Patients in group II revealed increased left atrial dimensions (P =.001), atrial wave of the pulmonary vein flow (P <.001), and Ep/Ap ratio (P <.001), and reduced LV ejection fraction and Ap (P <.001) compared with group I. Regression analysis showed that the strongest independent variable distinguishing normal from pseudonormal filling pattern was the Ep/Ap ratio. CONCLUSION: Ap evaluation offers a new diagnostic diastolic index, especially in the field of the pseudonormal pattern where the separation from normal is difficult.     

Plasma atrial natriuretic peptide and renin-aldosterone in patients with cirrhosis and ascites: basal levels, changes during daily activity and nocturnal diuresis.

Measurements of plasma atrial natriuretic peptide concentrations at 8 AM showed raised levels in 21 patients with cirrhosis and ascites (10.5 +/- 0.8 pmol/L) compared with levels in 10 age-matched controls (4.1 +/- 0.64 pmol/L; p less than 0.0001). In eight patients and 10 controls, atrial natriuretic peptide, plasma renin activity, plasma aldosterone and urinary sodium excretion were measured every 4 hr for 24 hr. Subjects were mobile between 8 AM and 11 PM and supine from 11 PM to 8 AM. In controls, urinary sodium excretion was highest between 4 PM and 11 PM (19.34 +/- 3.74 mumol/min) and lowest between midnight and 8 AM (7.06 +/- 1.23 mumol/min; p less than 0.001). In patients, urinary sodium excretion was 0.63 +/- 0.14 mumol/min between 4 PM and midnight and 1.85 +/- 0.71 mumol/min (p less than 0.08) between midnight and 8 AM. In patients during the day, mean plasma atrial natriuretic peptide concentration did not change despite large individual variation, but large, sustained rises in plasma renin activity and plasma aldosterone were seen. Correlations were noted between atrial natriuretic peptide and urinary sodium excretion between midnight and 8 AM (r = 0.65; p less than 0.02) and 4 PM and midnight (r = 0.54; p less than 0.05) but not between 8 AM and 4 PM. Plasma renin activity dropped from 12.54 +/- 2.49 at midnight to 7.41 +/- 0.88 pmol/hr/ml at 8 AM (p less than 0.05); plasma aldosterone decreased from 1,032 +/- 101 to 798 +/- 56 pmol/L (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of L-form Streptococcus pyogenes and of lipoteichoic acid on human cells in tissue culture.

These studies showed the destruction of growing primary and established human cell lines with a predilection for the group A streptococci by an L-form of Streptococcus pyogenes adapted to grow in isotonic media. Also, this L-form was detected by fluorescent antibody for longer periods of time than by viable count in infected but recovered tissue culture monolayers. Additional studies with human heart cells showed changes in their protein profile and fatty acid content (but not composition) after L-form infection. This report is the first to show that the morphological changes and death of human kidney cells by this viable L-form were mimicked by the structurally different lipoteichoic acids from this organism and its parental streptococcus. These lipoteichoic acids were also equally effective in preventing attachment of S. pyogenes to human cell monolayers, but their deacylation obviated these two activities. Finally, the attachment of the isotonic L-form, as well as the parental streptococcus, to growing human kidney cells suggested that a rigid cell wall is not a prerequisite for host attachment in vitro.     

A Model for Transport and Dispersion in the Circulatory System Based on the Vascular Fractal Tree

Materials are distributed throughout the body of mammals by fractal networks of branching tubes. Based on the scaling laws of the fractal structure, the vascular tree is reduced to an equivalent one-dimensional, tube model. A dispersion–convection partial differential equation with constant coefficients describes the heterogeneous concentration profile of an intravascular tracer in the vascular tree. A simple model for the mammalian circulatory system is built in entirely physiological terms consisting of a ring shaped, one-dimensional tube which corresponds to the arterial, venular, and pulmonary trees, successively. The model incorporates the blood flow heterogeneity of the mammalian circulatory system. Model predictions are fitted to published concentration-time data of indocyanine green injected in humans and dogs. Close agreement was found with parameter values within the expected physiological range. © 2003 Biomedical Engineering Society. PAC2003: 8710+e, 8719Hh, 8719Uv     

Pharmacodynamic considerations in bioequivalence assessment: comparison of novel and existing metrics.

This study addresses the utility of pharmacodynamic considerations to the assessment of bioequivalence (BE) studies. A novel methodology was developed and the performance of classic, nonclassic and novel BE indices was evaluated using extensive simulations of BE trials generated from a classic pharmacokinetic (PK)/pharmacodynamic (PD) model. Three novel indices based on drug's pharmacodynamics were developed and served as criteria for the assessment of all BE indices. Modified power curves were constructed and used for the analysis of BE trials from a PD point of view. All BE indices of either purely PK or PD nature were classified in a semiquantitative manner according to their strictness in declaring BE. The partial area until the peak concentration followed by the two newly proposed metrics (MARD, MARD(w1)) exhibited the most strict performance in declaring BE irrespective of the PK scenarios examined. The study opens new avenues in BE assessment since it places more emphasis on the PD aspects of the formulations.