Conversion to IPX066 from Standard Levodopa Formulations in Advanced Parkinson's Disease: Experience in Clinical Trials

Background:

Due to the short half-life of levodopa, immediate-release carbidopa-levodopa (IR CD-LD) produces fluctuating LD concentrations, contributing to a risk of eventual motor complications. IPX066 was designed to rapidly attain therapeutic LD concentrations and maintain them to allow a dosing interval of ∼6 hours.

Objective:

To extensively analyze the dosing data collected in IPX066 studies during open-label conversions from IR CD-LD alone or with entacapone (CLE) and identify patterns relevant for managing conversion in the clinical setting.

Methods:

Patients had ≥2.5 hours/day of “off” time despite a stable IR or CLE regimen. Suggested initial dosing conversion tables based on prior LD daily dosage were provided.

Results:

Of 450 patients previously treated with IR CD-LD and 110 with CLE, 87.3% and 82.7% completed conversion to IPX066, respectively. At the end of conversion, average IPX066 LD daily dosages were higher than pre-conversion dosages, with a mean conversion ratio of 2.1±0.6 for IR CD-LD and 2.8±0.8 for CLE; >90% of patients took IPX066 3 or 4 times/day, compared with a median of 5 times/day at baseline in both studies. After conversion, daily “off” time significantly decreased, with no significant increase in troublesome dyskinesia. The most common adverse event reported during conversion was nausea, with an incidence of 5.3% for conversion from IR and 7.3% from CLE.

Conclusions:

Among PD patients with substantial “off” time, a majority were safely converted to IPX066. The sustained LD profile from the IPX066 formulation allowed an increase in LD dose accompanied by improved motor functions, without increased troublesome dyskinesia.

Long-Term Treatment with Extended-Release Carbidopa-Levodopa (IPX066) in Early and Advanced Parkinson's Disease: A 9-Month Open-Label Extension Trial

BACKGROUND AND OBJECTIVE

IPX066 is a multiparticulate extended-release formulation of carbidopa-levodopa, designed to produce prolonged therapeutic levodopa plasma concentrations. This 9-month open-label extension study assessed its long-term safety and clinical utility in early and advanced Parkinson's disease (PD).

METHODS

Participants were enrolled from two phase III IPX066 studies and one open-label phase II study. Early PD patients were titrated to an appropriate dosing regimen while advanced patients started with regimens established in the antecedent studies. Adjustment was allowed throughout the extension. Clinical utility measures included the Unified Parkinson's Disease Rating Scale (UPDRS) and Patient Global Impression (PGI) ratings.

RESULTS

Among 268 early PD patients, 53.4 % reported adverse events (AEs) and 1.1 % (three patients) discontinued due to AEs; the most frequent AEs were nausea (5.6 %) and insomnia (5.6 %). Among 349 advanced patients, 60.2 % reported AEs and 3.7 % (13 patients) discontinued due to AEs; the most frequent AEs were dyskinesia (6.9 %) and fall (6.6 %). At month 9 (or early termination), 78.3 % of early patients were taking IPX066 three times daily (median: 720 mg/day) and 87.7 % of advanced patients were taking IPX066 three or four times daily (median: 1450 mg/day). Adjusting for 70 % bioavailability relative to immediate-release (IR) carbidopa-levodopa, the median dosages correspond to ~500 and ~1015 mg/day of IR levodopa in early and advanced PD, respectively. Based on the plasma profiles previously observed in PD patients, the IPX066 regimens in the extension can be estimated to provide a levodopa Cmax (maximum plasma drug concentration) similar to or lower than that provided by IR regimens during the antecedent trials. UPDRS and PGI findings showed sustained treatment effects throughout the extension.

CONCLUSION

During 9 months of extended use, IPX066 exhibited a safety/tolerability profile consistent with dopaminergic PD therapy.

Pharmacokinetics and Pharmacodynamics of Warfarin When Coadministered With Pentosan Polysulfate Sodium

The effect of pentosan polysulfate sodium on warfarin pharmacokinetics and pharmacodynamics was investigated in healthy subjects. Warfarin was titrated to an international normalized ratio between 1.4 and 1.8. Subjects continued their titrated dose of warfarin and received pentosan polysulfate sodium 100 mg or placebo every 8 hours for 7 days. The Cmax of R- and S-warfarin was approximately 840 to 890 ng/mL and 680 to 730 ng/mL, respectively, and was similar in the absence and presence of pentosan polysulfate sodium. The half-life for R- and S-warfarin was 52 to 56 hours and 36 to 40 hours, respectively. Prothrombin time, partial thromboplastin time, and the international normalized ratio for warfarin + placebo and warfarin + pentosan polysulfate sodium were comparable. The AUC(INR) indicated no treatment effect (P = .772); however, there was a period effect. Analysis of variance for the treatments by period indicated no treatment effect (P > .1). Adverse events were mild and included headache, epistaxis, and rash. Most adverse events were unrelated to treatment and were seen during warfarin titration. Pentosan polysulfate sodium did not affect warfarin pharmacokinetics or pharmacodynamics.

Effect of a kappa-opioid agonist, i.v. JNJ-38488502, on sensation of colonic distensions in healthy male volunteers

Kappa-opioid receptors are located on visceral pain fibres. JNJ-38488502 is a highly selective tetrapeptide kappa-opioid agonist with little access to the central nervous system and low risk of central nervous system side effects. The aim of the study was to evaluate the effects of i.v. JNJ-38488502 on sensations, including pain, during colonic distension. In a single-centre study, 23 healthy adult males underwent a single-dose, randomized, double-blind crossover study of JNJ-38488502 (0.42 mg kg(-1) i.v. infusion) vs placebo on left colon compliance, sensory thresholds and ratings during standard distensions. One participant could not undergo sensation studies. In the other 22, JNJ-38488502 increased colonic compliance (pressure at half-maximum volume 17.9 +/- 0.8 mmHg) compared to placebo (21.6 +/- 0.9 mmHg, P = 0.007). There was no significant effect on sensory thresholds which, however, were not reached by 44 mmHg in >50% of participants in both treatment phases. There were no significant treatment effects on sensory ratings to distensions at 8, 16, 24, 32 and 36 mmHg above baseline operating pressure. JNJ-38488502 was associated with increased urine output and plasma prolactin, consistent with kappa-opioid receptor activation. This study concluded that i.v. JNJ-38488502 induced kappa-opioid effects, but did not attenuate colonic sensations following random order colonic distension. Further studies of effects on pain sensations in health and disease are required.

Effect of dapoxetine on the pharmacokinetics and hemodynamic effects of tamsulosin in men on a stable dose of tamsulosin

The tolerability of dapoxetine, a short-acting selective serotonin reuptake inhibitor being developed for premature ejaculation, was evaluated when coadministered with tamsulosin. Adult men on a stable dose of tamsulosin were randomized to also receive dapoxetine 30 or 60 mg, or placebo, in a crossover design. Supine and standing vital signs were measured on days 1 and 7. Plasma samples were collected for measurement of tamsulosin, dapoxetine, and dapoxetine metabolites. Coadministration of dapoxetine with tamsulosin did not alter orthostatic profiles or affect the incidence of orthostatic hypotension. Tamsulosin and dapoxetine pharmacokinetics were not altered. Adverse events were reported by 5.4%, 10.9%, and 23.2% of participants receiving tamsulosin with placebo, dapoxetine 30 mg, and dapoxetine 60 mg, respectively. The most common adverse events were diarrhea, dizziness, headache, and nausea. Therefore, dapoxetine had no clinically important effects on the pharmacokinetics or orthostatic profile of tamsulosin in men on a stable tamsulosin regimen.

Efficacy and tolerability of dapoxetine in treatment of premature ejaculation: an integrated analysis of two double-blind, randomised controlled trials

BACKGROUND

No drugs are approved for treatment of premature ejaculation. Our aim was to determine the efficacy and tolerability of on-demand dapoxetine in patients with severe premature ejaculation.

METHODS

We determined the efficacy of dapoxetine in a prospectively predefined integrated analysis of two 12-week randomised, double-blind, placebo-controlled, phase III trials of identical design done independently, in parallel, at 121 sites in the USA. Men with moderate-to-severe premature ejaculation in stable, heterosexual relationships took placebo (n=870), 30 mg dapoxetine (874), or 60 mg dapoxetine (870) on-demand (as needed, 1-3 h before anticipated sexual activity). The primary endpoint was intravaginal ejaculatory latency time (IELT) measured by stopwatch. Safety and tolerability were assessed. All analyses were done on an intention-to-treat basis. The trials are registered at ClinicalTrials.gov, numbers NCT00211107 and NCT00211094.

FINDINGS

672, 676, and 610 patients completed in the placebo, 30 mg dapoxetine, and 60 mg dapoxetine groups, respectively. Dapoxetine significantly prolonged IELT (p<0.0001, all doses vs placebo). Mean IELT at baseline was 0.90 (SD 0.47) minute, 0.92 (0.50) minute, and 0.91 (0.48) minute, and at study endpoint (week 12 or final visit) was 1.75 (2.21) minutes for placebo, 2.78 (3.48) minutes for 30 mg dapoxetine, and 3.32 (3.68) minutes for 60 mg dapoxetine. Both dapoxetine doses were effective on the first dose. Common adverse events (30 mg and 60 mg dapoxetine, respectively) were nausea (8.7%, 20.1%), diarrhoea (3.9%, 6.8%), headache (5.9%, 6.8%), and dizziness (3.0%, 6.2%).

INTERPRETATION

On-demand dapoxetine is an effective and generally well tolerated treatment for men with moderate-to-severe premature ejaculation.

Effectiveness and tolerability of extended-release oxybutynin vs extended-release tolterodine in women with or without prior anticholinergic treatment for overactive bladder

The efficacy and the tolerability of extended-release oxybutynin chloride, 10 mg daily, and extended-release tolterodine tartrate, 4 mg daily, in women with or without prior anticholinergic treatment for overactive bladder (OAB) were compared in a post-hoc analysis of data from the Overactive Bladder: Performance of Extended Release Agents (OPERA) trial. The patient population and study methods have been described previously (Diokno et al., for the OPERA Study Group, Mayo Clin Proc 78:687-695, 2003). Among the group with anticholinergic experience, extended-release oxybutynin was significantly more effective than extended-release tolterodine in reducing micturition frequency at last observation (p=0.052). Complete freedom from urge incontinence was reported by significantly more patients taking oxybutynin than tolterodine at last observation (23.6 vs 15.1%, p=0.038). In addition, among patients completing a full 12 weeks of oxybutynin treatment, significantly greater reductions were observed compared with those taking tolterodine on the primary efficacy variable, number of urge incontinence episodes (p=0.049), and the combined total of urge and non-urge episodes (p=0.012), although the differences between treatment groups were not significant at last observation. In the anticholinergic-naïve group, efficacy and tolerability outcomes were similar across treatments, except that oxybutynin was associated with a significantly lower frequency of micturition at last observation (p=0.035). No efficacy differences favoring tolterodine were observed, and tolerability of the treatments was comparable. Dry mouth (mostly mild to moderate in severity) was reported significantly more often among participants taking extended-release oxybutynin than extended-release tolterodine (32.2 vs 19.2%, p=0.004), but only among those with previous anticholinergic experience. Discontinuation rates were comparably low across groups. The results demonstrate the appropriateness of initiating treatment for OAB with extended-release oxybutynin, particularly in women presenting with incontinence.

Oxybutynin chloride: alterations in drug delivery and improved therapeutic index

Oxybutynin chloride (Ditropan, Alza) is widely regarded as the most efficient antimuscarinic agent for the treatment of bladder detrusor dysfunction resulting in urinary urgency, frequency and urge incontinence. Oxybutynin metabolism occurs primarily in the proximal gastrointestinal tract and the hepatic circulation and is mediated by the cytochrome P450 3A4 isozyme. The major degradation products are desethyloxybutynin, which possesses pharmacological activity, and phenylcyclohexylglycolic acid, which is metabolically inert. A major limitation to long-term compliance with immediate-release oxybutynin remains the necessity for twice- or thrice-daily dosing regimens to provide sustained pharmacological efficacy. Side effects induced by cytochrome P450 metabolism of oxybutynin into the primary metabolite desethyloxybutynin within the gut wall substantially affect the tolerability of the compound within the individual. The oral osmotic delivery system provides unique advantages for drug delivery and substantially alters the tolerability profile of the oxybutynin chloride compound. This extended-release formulation consists of a two component core encapsulated by a semi-permeable membrane. The osmotic gradient between the surrounding environment and the inner core of the delivery system remains constant and water absorption within the capsule is controlled by the semipermeable membrane causing a controlled release of drug, which is sustained over 24 h. Herein are reviewed the various pre- and post-approval trials which have documented the overall therapeutic index of the oral osmotic oxybutynin (Ortho-McNeil Pharmaceuticals). Subsequent post-market surveillance issues are reviewed as are new developments in oxybutynin delivery.

Effect of pravastatin on cardiovascular events in older patients with myocardial infarction and cholesterol levels in the average range. Results of the Cholesterol and Recurrent Events (CARE) trial

BACKGROUND

A majority of all myocardial infarctions occur in patients who are 65 years of age or older and have average cholesterol levels, but little information is available on whether cholesterol lowering in such patients reduces the rate of recurrent cardiovascular disease.

OBJECTIVE

To determine whether pravastatin reduces the rate of recurrent cardiovascular events in older patients.

DESIGN

Subset analysis of a randomized, controlled trial.

SETTING

80 hospitals and affiliates in the United States and Canada.

PATIENTS

1283 patients aged 65 to 75 years who had had myocardial infarction and had a plasma total cholesterol level less than 6.2 mmol/L (240 mg/dL) and a low-density lipoprotein cholesterol level of 3.0 to 4.5 mmol/L (115 to 174 mg/dL).

INTERVENTION

Pravastatin, 40 mg/d, or placebo.

MEASUREMENTS

Five-year event rates of major coronary events (coronary death, nonfatal myocardial infarction, angioplasty, or bypass surgery) and stroke.

RESULTS

Major coronary events occurred in 28.1% of placebo recipients and 19.7% of pravastatin recipients (difference, 9.0 percentage points [95% CI, 4 to 13 percentage points]; relative risk reduction, 32%; P < 0.001). Coronary death occurred in 10.3% of the placebo group and in 5.8% of the pravastatin group (difference, 4.6 percentage points [CI, 1.9 to 6.5 percentage points]; relative risk reduction, 45%; P = 0.004). Stroke incidence was 7.3% in the placebo group and 4.5% in the pravastatin group (absolute reduction, 2.9 percentage points [CI, 0.3 to 4.5 percentage points]; relative reduction, 40%; P = 0.03). The numbers of older patients needed to treat for 5 years were 11 (CI, 8 to 24) to prevent a major coronary event and 22 (CI, 15 to 53) to prevent a coronary death. For every 1000 older patients treated, 225 cardiovascular hospitalizations would be prevented compared with 121 hospitalizations in 1000 younger patients.

CONCLUSIONS

In older patients with myocardial infarction and cholesterol levels in the average range, pravastatin is associated with a clinically important reduction in risk for major coronary events and stroke. Given the high cardiovascular event rate in older patients, the potential for absolute benefit in this age group is substantial.

Diabetes care for Medicare beneficiaries. Attitudes and behaviors of primary care physicians

OBJECTIVE

To obtain information related to primary care physician (PCP) attitudes, knowledge, and practice patterns, as well as perceptions about barriers to care and the use of materials to assist in the delivery of diabetes care for elderly patients in the office setting.

RESEARCH DESIGN AND METHODS

A survey was mailed to a random sample (n = 900) of PCPs (internal medicine, family practice, and general practice physicians and endocrinologists) from the states of Alabama, Iowa, and Maryland who met selection criteria and provided diabetes care to > or = 25 Medicare beneficiaries during calendar year 1993.

RESULTS

Respondents provided self-reported information regarding diabetes care for elderly patients. PCP respondents (n = 370) considered blood glucose control to be the most important treatment goal. Most respondents (92%) considered acceptable GHb values to be those < 8%. Blood pressure measurement and foot inspections for the detection of ulcers and infection were the most commonly reported routine procedures performed as part of an office visit. Laboratory tests reported to be frequently ordered included GHb, serum creatinine, and proteinuria tests. Patient nonadherence to the treatment regimen was reported to be the most common barrier to care. The majority of respondents reported using two treatment aids in caring for patients with diabetes.

CONCLUSIONS

The results of this study provide some evidence that PCP self-reported attitudes, knowledge, and practice patterns in delivering diabetes care for elderly patients in the office setting more closely reflect current recommended practice than reported in previous physician surveys. Opportunities for improvement still exist.

Effect of pravastatin on cardiovascular events in women after myocardial infarction: the cholesterol and recurrent events (CARE) trial

OBJECTIVES

We sought to determine the effect of pravastatin on recurrent cardiovascular events in women with average cholesterol levels after myocardial infarction (MI).

BACKGROUND

Little information is available on the effectiveness of lipid lowering in secondary prevention of coronary heart disease (CHD) in women; in particular, those with CHD and average cholesterol levels.

METHODS

In the Cholesterol and Recurrent Events (CARE) trial, 576 postmenopausal women, between 3 and 20 months after MI, with a total cholesterol level <240 mg/dl and a low density lipoprotein cholesterol level 115 to 174 mg/dl, were randomized to receive pravastatin 40 mg/day or matching placebo for a median follow-up period of 5 years. The main outcome measures were combined coronary events (coronary death, nonfatal MI, percutaneous transluminal coronary angioplasty [PTCA] or coronary artery bypass graft surgery [CABG]), the primary trial end point (coronary death or nonfatal MI) and stroke.

RESULTS

Women treated with pravastatin had a risk reduction of 43% for the primary end point (p = 0.035), 46% for combined coronary events (p = 0.001), 48% for PTCA (p = 0.025), 40% for CABG (p = 0.14) and 56% for stroke (p = 0.07). The 3,583 men in the CARE trial also showed a reduction in risk, but the magnitude tended to be less. Pravastatin improved plasma lipids similarly in men and women. There were no differences in risk of coronary events in the placebo group between men and women. Minor differences between men and women were present in baseline characteristics and treatment for MI, in general, conferring a higher risk status and a lower incidence of CABG in the women.

CONCLUSIONS

Pravastatin led to significant early reduction of a wide range of cardiovascular events in post-MI women with average cholesterol levels.

Comparison of different strategies of molecular genetic monitoring following autologous stem cell transplantation in patients with follicular lymphoma

Two different molecular genetic methods were compared for their suitability for monitoring minimal residual disease in patients with follicular lymphoma (FL) treated with high-dose therapy and autologous stem cell transplantation. Fifteen patients were selected because of a specific PCR-amplifiable t(14;18) mbr translocation. PCR amplification of rearrangements of the complementary region III (CDRIII) of the immunoglobulin heavy chain gene was also carried out. After autologous stem cell transplantation, patients were prospectively monitored with both molecular genetic methods. Seven of the 15 patients with detectable t(14;18) prior to transplantation were persistently negative during follow-up to 32 months post transplant. None of these patients relapsed, whereas four of eight patients with positive PCR signals post transplant relapsed. Comparing t(14;18) and PAGE results, we observed six patients showing clonal signals in CDRIII PAGE in spite of persistent negativity of t(14;18) PCR. We concluded that in patients with FL, t(14;18) PCR is superior to CDRIII PCR in terms of sensitivity and specificity. A positive t(14;18) PCR during the first year post transplant is highly predictive for disease recurrence. CDRIII PCR may be used for monitoring in t(14;18) negative lymphomas. However, due to the poor specificity of conventional gel electrophoresis PCR, the use of clone-specific probes is highly desirable.