Outlook: Clinical Trials

Tiotropium Improved Lung Function in Asthma Patients

Recent data from a 3-way, double-blind clinical trial showed that tiotropium, when added to an inhaled glucocorticoid, improved symptoms as well as lung function in subjects with inadequately controlled asthma.¹ The study evaluated the addition of tiotropium bromide in 210 patients with asthma to an inhaled glucocorticoid compared with doubling the dose of the inhaled glucocorticoid or the addition of salmeterol. The primary end point of the trial was measurement of the morning peak expiratory flow (PEF).

When compared with doubling the dose of the inhaled corticosteroid, the addition of tiotropium demonstrated superiority in the primary outcome of PEF with a mean difference of 25.8 liters per minute (P <.001). Additionally, tiotropium was superior in improving evening PEF with a difference of 35.3 liters per minute (P <.001). Tiotropium also improved the proportion of asthma-controlled days (difference of 0.079; P = .01), forced expiratory volume in 1 second before bronchodilation (difference of 0.10 liter; P = .004), and daily symptom scores (difference of -0.11 point; P <.001). When compared with salmeterol, the addition of tiotropium was noninferior for all end points. Investigators concluded that the addition of tiotropium to an inhaled glucocorticoid improved symptoms and lung function in patients with asthma compared with doubling the dose of inhaled glucocorticoid.

Buprenorphine Implants Reduced Opioid Use

Recent data from a randomized, placebocontrolled clinical trial demonstrated that when compared with placebo, the use of buprenorphine implants resulted in less opioid use over 16 weeks.³

Investigators randomized 163 opioiddependent patients, aged 18 to 65 years, to receive either buprenorphine implants (n = 108) or placebo implants (n = 55). Patients went through an induction with sublingual buprenorphine—naloxone tablets followed by 4 buprenorphine implants (80 mg per implant) or 4 placebo implants. The primary end point was the percentage of urine samples negative for illicit opioids.

Results showed that the buprenorphine implant group had significantly more negative urine samples during weeks 1 through 16 (P = .04). Patients in the buprenorphine implant group had a 40.4% mean percentage of negative urine samples across weeks 1 through 16 (95% confidence interval [CI], 34.2%-46.7%) compared with 28.3% (95% CI, 20.3%-36.3%) in the placebo group. Patients in the buprenorphine group also had fewer withdrawal symptoms, lower patient ratings of craving, and experienced greater change on clinician global ratings of severity of dependence and improvement.

Home Testing of International Normalized Ratio Not Superior to Clinic Testing

In a recent clinical trial, the effect of home international normalized ratio (INR) testing was compared with clinic-based testing.² Investigators randomly assigned 2922 patients taking warfarin due to mechanical heart valves or atrial fibrillation to either weekly self-testing of INR at home or monthly testing in a clinic. The primary end point was timed to a first major event, defined as stroke, major bleeding episode, or death.

Patient follow up lasted 2 to 4.75 years, totaling 8730 patient-years. Patients in the self-testing group did not experience a significantly longer time to first primary event (hazard ratio, 0.88; 95% confidence interval, 0.75 to 1.04; P = .14). Clinical outcomes were similar between groups with the exception of minor bleeding episodes, which occurred more frequently in the selftesting group. Throughout the follow-up period, patients in the self-testing group had a significant improvement in the percentage of time that INR was within target range (absolute difference 3.8 percentage points; P <.001). Additionally, the self-testing group had a small improvement in patient satisfaction with anticoagulation therapy (P = .002) and quality of life (P <.001). Investigators concluded that weekly self-testing of INR did not delay time to a first stroke, major bleeding episode, or death compared with high-quality clinic testing.

Estrogen Therapy Increases Risk of Nephrolithiasis

The incidence of nephrolithiasis in the Women’s Health Initiative estrogen alone and estrogen plus progestin trials was recently reviewed. In the conjugated estrogens (CEE) trial, postmenopausal women with hysterectomy (n = 10,739) received either 0.625 mg per day of CEE or placebo. In the estrogen plus progesterone trial, a total of 16,608 participants received either placebo or CEE plus medroxyprogesterone acetate 2.5 mg per day.

Results showed that estrogen therapy significantly increased the risk of nephrolithiasis from 34 to 39 cases per 10,000 patient-years (hazard ratio, 1.21; 95% confidence interval, 1.03-1.44). Investigators found that the increased risk of nephrolithiasis was independent of concomitant progestin use. They concluded that estrogen therapy increases the risk of nephrolithiasis in healthy postmenopausal women. PT

Michele Reed, PharmD Dr. Reed received her Doctor of Pharmacy degree from the University of the Sciences in Philadelphia, Pennsylvania, and currently works as a medical editor in the greater Philadelphia area.