Cost-Effectiveness Analysis of Microscopic and Endoscopic Transsphenoidal Surgery Versus Medical Therapy in the Management of Microprolactinoma in the United States.

BACKGROUND: Although prolactinomas are treated effectively with dopamine agonists, some have proposed curative surgical resection for select cases of microprolactinomas to avoid life-long medical therapy. We performed a cost-effectiveness analysis comparing transsphenoidal surgery (either microsurgical or endoscopic) and medical therapy (either bromocriptine or cabergoline) with decision analysis modeling. METHODS: A 2-armed decision tree was created with TreeAge Pro Suite 2012 to compare upfront transsphenoidal surgery versus medical therapy. The economic perspective was that of the health care third-party payer. On the basis of a literature review, we assigned plausible distributions for costs and utilities to each potential outcome, taking into account medical and surgical costs and complications. Base-case analysis, sensitivity analysis, and Monte Carlo simulations were performed to determine the cost-effectiveness of each strategy at 5-year and 10-year time horizons. RESULTS: In the base-case scenario, microscopic transsphenoidal surgery was the most cost-effective option at 5 years from the time of diagnosis; however, by the 10-year time horizon, endoscopic transsphenoidal surgery became the most cost-effective option. At both time horizons, medical therapy (both bromocriptine and cabergoline) were found to be more costly and less effective than transsphenoidal surgery (i.e., the medical arm was dominated by the surgical arm in this model). Two-way sensitivity analysis demonstrated that endoscopic resection would be the most cost-effective strategy if the cure rate from endoscopic surgery was greater than 90% and the complication rate was less than 1%. Monte Carlo simulation was performed for endoscopic surgery versus microscopic surgery at both time horizons. This analysis produced an incremental cost-effectiveness ratio of $80,235 per quality-adjusted life years at 5 years and $40,737 per quality-adjusted life years at 10 years, implying that with increasing time intervals, endoscopic transsphenoidal surgery is the more cost-effective treatment strategy. CONCLUSIONS: On the basis of the results of our model, transsphenoidal surgical resection of microprolactinomas, either microsurgical or endoscopic, appears to be more cost-effective than life-long medical therapy in young patients with life expectancy greater than 10 years. We caution that surgical resection for microprolactinomas be performed only in select cases by experienced pituitary surgeons at high-volume centers with high biochemical cure rates and low complication rates.

The role of primary pharmacological therapy in acromegaly.

BACKGROUND AND OBJECTIVES: Primary pharmacological therapy may be the only viable treatment option for many patients with acromegaly, especially those presenting with advanced disease with large inoperable tumors. Long-acting somatostatin analogs are currently the first-line treatment of choice in this setting, where they provide biochemical control and reduce tumor size in a significant proportion of patients. We herein present a brief overview of the role of primary pharmacological therapy in the treatment of acromegaly within the context of Latin America and support this with a representative case study. CASE DESCRIPTION: A 20 year old male presented with clinical and biochemical evidence of acromegaly. The glucose-suppressed growth hormone (GH) was 5.3 µg/L, his insulin-like growth factor-1(IGF-1) was 3.5 times the ULN and serum prolactin greater than 4,000 µg/L. Pituitary MRI revealed a large and invasive mass, extending superiorly into the optic chiasm and laterally into the left cavernous sinus. He was treated with a combination of octreotide and cabergoline with remarkable clinical improvement, normalization of GH and IGF-1 values and striking shrinkage of the adenoma. CONCLUSION: This case illustrates how effective the pharmacological therapy of acromegaly can be and yet at the same time, raises several important issues such as the need for life-long treatment with costly medications such as the somatostatin analogs. Access to these agents may be limited in regions where resources are restricted and clinicians face challenges in order to make the most efficient use of available options.

The impact in Japan of regulatory action on prescribing of dopamine receptor agonists: analysis of a claims database between 2005 and 2008.

BACKGROUND: Use of the ergot-derived dopamine receptor agonists (cabergoline and pergolide) is associated with an increased risk of cardiac valvulopathy. Pergolide was withdrawn from the US market in 2007 because of the risk of valvular heart disease, while the European Medicines Agency (EMA) required a reduction in the maximum daily dosage of cabergoline and pergolide from 6 mg/day to 3 mg/day in 2008. In Japan, the package inserts of both drugs were revised in April 2007 to request that physicians conduct periodic ultrasonic cardiography (UCG) examinations for patients taking cabergoline or pergolide. Also, through face-to-face communication with medical representatives of drug companies, physicians were informed that use of cabergoline and pergolide has increased the risk of valvulopathy. However, cabergoline and pergolide have remained in wide use, even following the regulatory actions. OBJECTIVE: The objective of this study was to assess the impact of actions, including the package insert revision in April 2007, to encourage periodic UCG. METHODS: Data on monthly claims (January 2005-October 2008) covering 330 000 patients were obtained from a Japanese database vendor. We selected patients ≥40 years of age with Parkinson's disease. The impact of the regulatory action on the proportion of patients with Parkinson's disease prescribed cabergoline or pergolide was assessed by segmented regression analysis and by a statistical model of the rates of UCG examination in patients taking/not taking cabergoline or pergolide before and after the action. We also compared the use of cabergoline and pergolide before and after the action with that of other antiparkinson drugs. RESULTS: Of 574 patients with Parkinson's disease, the proportion of patients prescribed cabergoline or pergolide did not decrease but rather tended to increase after the action when analysed by segmented regression analysis (p = 0.13). Similarly, the proportion of the prevalent and incident users of cabergoline or pergolide did not change between two 19-month periods before and after the action. The adjusted rates of UCG examination per person-year before and after the action were both 0.02 in those not prescribed cabergoline or pergolide, but 0.02 before the action and 0.09 after the action in those taking either drug. The excess UCG examination rate of cabergoline or pergolide attributable to the action was 0.08 per person-year (95% CI 0.03, 0.11). While 1 of 49 (2%) patients taking cabergoline or pergolide had a UCG up to 19 months before the action, 9 of 36 (25%) patients taking cabergoline or pergolide had a UCG up to 19 months after the action. Annual sales from 2004 to 2008 were 195, 195, 170, 110 and 75 billion yen, respectively, and the number of valvulopathy events, including incompetence of aortic/mitral/tricuspid valves and cardiac valve disease, per annual sales from 2004 to 2008 were estimated at 0.23, 0.03, 0.08, 0.25 and 0.19 per billion yen, respectively. CONCLUSIONS: Following the actions in April 2007, no decrease in the use of cabergoline or pergolide occurred, although more patients administered the drug underwent a UCG. However, those undergoing a UCG represented one-quarter of the total number prescribed cabergoline or pergolide. To mitigate the risk, additional risk management tools such as patient registration may be needed to secure careful clinical examination (including UCG examination, if necessary) for cardiac function.

Assessment of cardiac valve dysfunction in patients receiving cabergoline treatment for hyperprolactinaemia.

OBJECTIVE: Cabergoline is a highly effective medical treatment for patients with hyperprolactinaemia. There is an increased risk of valvular heart disease in patients receiving cabergoline for Parkinson's disease. This study examined whether cabergoline treatment of hyperprolactinaemia is associated with a greater prevalence of valvulopathy. DESIGN: Cross-sectional, two-dimensional echocardiographic study performed by a single echocardiographer. PATIENTS: Seventy-two patients (median age 36 years, 19 men) receiving cabergoline for hyperprolactinaemia, and 72 controls prospectively matched for age, sex and cardiovascular risk factors. Measurements Assessment of valvular mobility, regurgitation and morphology. RESULTS: Median cumulative dose exposure for cabergoline was 126 (58-258) mg, and patients had received cabergoline for 53 (26-96) months. The frequency of mild mitral regurgitation was identical (5/72, 7%) in patient and control groups. Mild aortic regurgitation was not significantly different between groups (4/72 [controls] vs 2/72 [patients], P = 0.681). There was only one case of tricuspid regurgitation, which was mild and observed in a cabergoline-treated patient. Nodular thickening of the right coronary cusp, noncoronary cusp or left coronary cusp of the aortic valve was observed at a similar frequency in both groups. There were no cases of extensive thickening of any valvular leaflet. CONCLUSION: Our data demonstrates that there is no association between cabergoline treatment for hyperprolactinaemia and valvulopathy. This study therefore supports continued use of low-dose cabergoline for patients with hyperprolactinaemia.

Prevalence of valvular heart disease in a cohort of patients taking cabergoline for management of hyperprolactinemia.

OBJECTIVE: To determine the prevalence of valvular heart disease in a cohort of patients taking cabergoline for the management of hyperprolactinemia. METHODS: A retrospective review of medical records identified patients with hyperprolactinemia who underwent evaluation at Vanderbilt University Medical Center between January and June 2007. The medical records of those patients who were prescribed cabergoline and who underwent elective echocardiography were reviewed for details pertaining to cardiac valvular abnormalities and cabergoline use. RESULTS: Forty-five patients (mean age, 41 +/- 10 years [SD]) taking 0.91 +/- 0.96 mg of cabergoline per week for a mean duration of 39 +/- 29 months underwent echocardiography. Abnormalities of the cardiac valves were present in 3 patients (7%): 1 patient exhibited mild mitral regurgitation, 1 patient had focal aortic valve thickening, and 1 patient demonstrated mitral valve thickening. We found no significant difference in either the cumulative dose of cabergoline (P = .800) or the duration of cabergoline therapy (P = .745) between those patients with and those without these echocardiographic abnormalities. CONCLUSION: We found echocardiographic valve abnormalities in 3 of 45 patients (7%) who had been prescribed cabergoline for the management of hyperprolactinemia. This prevalence of valvular heart disease after approximately 3 years of cabergoline treatment is no different from that previously reported in normal populations as determined by echocardiography.

Assessment of valvulopathy in Parkinson's disease patients on pergolide and/or cabergoline.

OBJECTIVE: To assess the effect of ergot derivatives on cardiac valves in patients with Parkinson's disease (PD). MATERIALS AND METHODS: Echocardiography was performed on 46 PD patients who used either pergolide or cabergoline (MonoPD) or both (MixPD) for a minimum of 1 year and 49 age-matched healthy controls. Valvular regurgitation was graded as mild, moderate and severe. MonoPD and MixPD groups were compared with regard to demographic features, drug profile and valvulopathy. RESULTS: The PD group had a mean age of 63 years, agonist duration of 3.8 years and agonist equivalent dose of 3.5mg/day. Moderate regurgitation in all three valves was significantly more common in the PD group than the controls. Severe valvular regurgitation was not observed in either group, with the exception of one PD patient. The frequency of valvulopathy and doses of agonists did not differ between MixPD and MonoPD groups. CONCLUSION: PD patients on dopamine ergot agonists are prone to moderate valvular regurgitation more than age-matched controls. However, the frequency of valvulopathy was similar in patients who used either one or more agonists.

Cabergoline : a review of its use in the treatment of Parkinson's disease.

Cabergoline is a synthetic ergoline dopamine agonist with a high affinity for dopamine D2 receptors and a long elimination half-life. This agent provides continuous dopaminergic stimulation with once-daily administration. Adjuvant oral cabergoline is usually well tolerated and effective in controlling symptoms in patients with advanced Parkinson's disease experiencing response fluctuations to long-term levodopa therapy. In patients with early Parkinson's disease, cabergoline (with or without levodopa) is well tolerated and effective in controlling disease symptoms, and may reduce the risk of developing drug-induced motor complications. Data from two pharmacoeconomic analyses suggest that cabergoline may be a cost-effective treatment option versus levodopa in patients with early Parkinson's disease, and highlight the need for further evaluation of the drug in this indication.

Pharmacological approach to the treatment of acromegaly.

The treatment of patients with persistently active acromegaly has been facilitated over the past decade by the advent of highly specific and selective pharmacological agents. Somatostatin analogs, derived from the native inhibitory hormone somatostatin, are available in extended-duration preparations and are effective in reducing serum levels of growth hormone (GH) and insulin-like growth factor-I (IGF-I) as well as in improving the adverse clinical effects of acromegaly. Cabergoline, an agonist with a specificity for the dopamine D-2 receptor, has been shown to suppress IGF-I levels and induce tumor shrinkage in 35 and 50% of patients, respectively. The GH receptor antagonists compete with naturally occurring GH for binding with the GH receptor. As such, pegvisomant normalizes circulating IGF-I levels in 80 to 90% of patients with acromegaly. This last line of therapy should be considered for use in patients in whom surgery and medical therapy with somatostatin and/or dopamine agonists are either ineffective or poorly tolerated.

Cabergoline versus levodopa monotherapy: a decision analysis.

We evaluated the incremental cost-effectiveness of cabergoline compared with levodopa monotherapy in patients with early Parkinson's disease (PD) in the German healthcare system. The study design was based on cost-effectiveness analysis using a Markov model with a 10-year time horizon. Model input data was based on a clinical trial "Early Treatment of PD with Cabergoline" as well as on cost data of a German hospital/office-based PD network. Direct and indirect medical and nonmedical costs were included. Outcomes were costs, disease stage, cumulative complication incidence, and mortality. An annual discount rate of 5% was applied and the societal perspective was chosen. The target population included patients in Hoehn and Yahr Stages I to III. It was found that the occurrence of motor complications was significantly lower in patients on cabergoline monotherapy. For patients aged >/=60 years of age, cabergoline monotherapy was cost effective when considering costs per decreased UPDRS score. Each point decrease in the UPDRS (I-IV) resulted in costs of euro;1,031. Incremental costs per additional motor complication-free patient were euro;104,400 for patients <60 years of age and euro;57,900 for patients >/=60 years of age. In conclusion, this decision-analytic model calculation for PD was based almost entirely on clinical and observed data with a limited number of assumptions. Although costs were higher in patients on cabergoline, the corresponding cost-effectiveness ratio for cabergoline was at least as favourable as the ratios for many commonly accepted therapies.

The assessment of cabergoline efficacy and tolerability in patients with pituitary prolactinoma type.

Prolactinoma is the most frequent type of secreting pituitary tumours. In the treatment, pharmacotherapy with dopamine agonists is considered the first-line option. For many years bromocriptine, a D1 and D2 dopamine receptor agonist, has been the standard medicine for hyperprolactinemic patients. However, the treatment is frequently associated with intolerance or resistance. Recently cabergoline, a long acting, ergoline-derived, selective D2 agonist has become available and has been promoted as the initial treatment. Therefore the object of four studies was to assess the efficacy and tolerability of cabergoline in patients with prolactin-secreting pituitary adenomas. 17 patients, 13 women at the age of 21-55 years (average 37.1) and 4 men at the age of 29-45 years (average 36.3), with pathological hyperprolactinemia due to pituitary tumours were involved in the study. In all patients the increased pretreatment concentration of PRL was observed, ranging from 1047 to 1678 mlU/ml (mean 1369 mlU/ml). MRI scans revealed microprolactinomas in 11 (64.7%) cases and macroadenomas in 6 (35.3%) cases. None of the patients had previously undergone pituitary surgery and all of them were newly diagnosed, previously untreated. The patients were treated with cabergoline for 6 months. Cabergoline therapy was started at a dose of 0.5 mg twice a week for the first two months, then the dose was decreased to a 0.25 mg twice a week and finally maintained at 0.25 mg a week. After 6 months of the therapy, the normalization of serum PRL concentrations (from mean 1358 mlU/ml to mean 420 mlU/ml; p < 0.001) was achieved in 13 (76.5%) patients (8 with microprolactinoma and 5 with macroprolactinoma). In the remaining 4 patients PRL levels remained elevated but were decreased from mean 1403 mIU/ml to mean 812 mIU/ml. There were no differences, regarding CAB efficacy in lowering PRL levels, between patients with micro- and macroadenomas (p > 0.05). About 90% women resumed menstrual cycles in our study. All the other clinical pretreatment symptoms disappear in the course of the therapy. The tumour shrinkage, confirmed by control MRI was noted in 2 patients (33%) with macroprolactinoma. Cabergoline was tolerated satisfactorily by all our patients. The results have confirmed a high efficacy and a very good tolerability of CAB in the treatment of patients with pituitary adenomas. Together with a very convenient administration, such therapy can provide a very good patient compliance thus should be considered the first line option in patients with prolactinomas.

Detecting dose-response using contrasts: asymptotic power and sample size determination for binomial data.

Recently, Stewart and Ruberg proposed the use of contrast tests for detecting dose-response relationships. They considered in particular bivariate contrasts for healing rates and gave several possibilities of defining adequate sets of coefficients. This paper extends their work in several directions. First, asymptotic power expressions for both single and multiple contrast tests are derived. Secondly, well known trend tests are rewritten as multiple contrast tests, thus alleviating the inherent problem of choosing adequate contrast coefficients. Thirdly, recent results on the efficient calculation of multivariate normal probabilities overcome the traditional simulation-based methods for the numerical computations. Modifications of the power formulae allow the calculation of sample sizes for given type I and II errors, the spontaneous rate, and the dose-response shape. Some numerical results of a power study for small to moderate sample sizes show that the nominal power is a reasonably good approximation to the actual power. An example from a clinical trial illustrates the practical use of the results.

Resistance to cabergoline as compared with bromocriptine in hyperprolactinemia: prevalence, clinical definition, and therapeutic strategy.

To evaluate the prevalence of resistance to cabergoline treatment, we studied 120 consecutive de novo patients (56 macroadenoma, 60 microadenoma, 4 nontumoral hyperprolactinemia) treated with cabergoline (CAB) compared with 87 consecutive de novo patients (28 macroadenoma, 44 microadenoma, 15 nontumoral hyperprolactinemia) treated with bromocriptine (BRC) for 24 months. Resistance was evaluated as inability to normalize serum PRL levels (first end point) and to induce tumor shrinkage (second end point). After 24 months, PRL normalization and tumor shrinkage after CAB and BRC treatments, respectively, were obtained in 82.1% and 46.4% of macroprolactinomas (P < 0.001) and in 90% vs. 56.8% of microprolactinomas (P < 0.001). The median doses of CAB and BRC able to fulfill the two criteria of treatment success were 1 mg/wk and 7.5 mg/d in macroprolactinomas, 1 mg/wk and 5 mg/d in microprolactinomas, and 0.5 mg/wk and 3.75 mg/d in nontumoral hyperprolactinemia. Hyperprolactinemia persisted in 17.8% of macroprolactinomas, 10% of microprolactinomas, and after CAB at doses of 5-7 mg/wk and in 53.6% of macroprolactinomas, 43.2% of microprolactinomas, and 20% of nontumoral hyperprolactinemic patients, after BRC at doses of 15-20 mg/d. In these resistant macro- and microprolactinomas, the maximal tumor diameter was reduced by 43.7 +/- 3.6% and 22.1 +/- 3.7% and by 59.3 +/- 7.1% and 4.3 +/- 2.1% after CAB and BRC, respectively (P < 0.001). In conclusion, long-term CAB treatment induced the successful control of hyperprolactinemia associated with tumor shrinkage in a higher proportion of patients than did BRC treatment. In a small number of patients (i.e. 17.8% of macroprolactinomas and 10% of microprolactinomas), however, CAB treatment did not normalize serum PRL levels despite reducing tumor mass, even at very high doses. Therefore, an absence of tumor shrinkage cannot be considered as end point to indicate resistance to CAB, and increasing the dose of CAB higher than 3 mg/wk does not seem to be helpful in controlling PRL hypersecretion.

Adjunctive cabergoline therapy of Parkinson's disease: comparison with placebo and assessment of dose responses and duration of effect.

Adjunctive cabergoline or placebo, in doses up to 5 mg daily, were administered to Parkinson's disease patients with short-duration levodopa responses in a 6-month double-blind trial. The 13 patients randomized to cabergoline and completing the study had significantly improved Unified Parkinson's Disease Rating Scale (UPDRS) motor scores and timed hand-tapping test scores. Serial measurements on test days documented improved scores: (a) before the first levodopa (and cabergoline) dose of the day, (b) at the time of the peak levodopa effect, and (c) at the end of the levodopa response cycle, 5 h after test doses. Continued testing verified that these therapeutic responses were sustained for at least 48 h after the last cabergoline dose. Patients randomized to placebo failed to improve on any of these measures. In a subsequent open-label dose-escalation phase, further improvement was documented as the dosage was gradually raised to 10 mg daily. As in the double-blind phase, levodopa reduction allowed the improvement to occur in the absence of significantly increased dyskinesias. Other side effects were more substantial with higher doses, however, including two of 11 patients with hallucinations and confusion. In summary, adjunctive single-daily-dose cabergoline therapy resulted in long-lasting, dose-related improvement in parkinsonism not seen in patients receiving placebo.

Double-blind assessment of potential pergolide-induced cardiotoxicity.

Possible pergolide-induced cardiotoxicity has been reported in open trials. Over a 6-month period of observation, we prospectively analyzed ECGs and 24-hour ambulatory ECG in 23 patients with Parkinson's disease who were randomized in a double-blind fashion to pergolide or placebo treatments. Pergolide therapy was associated with a mild and transient bradycardiac effect, but no clinically significant cardiotoxicity.

Assessment of hypokinesia in Parkinsonism.

The measurement of movement time provides a satisfactory objective measure of hypokinesia in parkinsonism. It is relatively constant in normal subjects, and it is often greatly prolonged in parkinsonism and correlates with clinical disability. The reaction time is only of limited value, because of small difference from normal values and wide individual variations.