Effect of 3, 2-Drug Combinations of Antihypertensive Therapies on Blood Pressure Variability in Black African Patients: Secondary Analyses of the CREOLE Trial

Background:

The effect of 3 commonly recommended combinations of anti-hypertensive agents—amlodipine plus hydrochlorothiazide (calcium channel blocker [CCB]+thiazide), amlodipine plus perindopril (CCB+ACE [angiotensin-converting enzyme]-inhibitor), and perindopril plus hydrochlorothiazide (ACE-inhibitor+thiazide) on blood pressure variability (V) are unknown.

Methods:

We calculated the blood pressure variability (BPV) in 405 patients (130, 146, and 129 randomized to ACE-inhibitor+thiazide, CCB+thiazide, and CCB+ACE-inhibitor, respectively) who underwent ambulatory blood pressure monitoring after 6 months of treatment in the Comparisons of Three Combinations Therapies in Lowering Blood Pressure in Black Africans trial (CREOLE) of Black African patients. BPV was calculated using the SD of 30-minute interval values for 24-hour ambulatory BPs and for confirmation using the coefficient of variation. Linear mixed model regression was used to calculate mean differences in BPV between treatment arms. Within-clinic BPV was also calculated from the mean SD and coefficient of variation of 3 readings at clinic visits.

Results:

Baseline distributions of age, sex, and blood pressure parameters were similar across treatment groups. Participants were predominately male (62.2%) with mean age 50.4 years. Those taking CCB+thiazide had significantly reduced ambulatory systolic and diastolic BPV compared with those taking ACE-inhibitor+thiazide. The CCB+thiazide and CCB+ACE-inhibitor groups showed similar BPV. Similar patterns of BPV were apparent among groups using within-clinic blood pressures and when assessed by coefficient of variation.

Conclusions:

Compared with CCB-containing combinations, ACE-inhibitor plus thiazide was associated with higher levels, generally significant, of ambulatory and within-clinic systolic and diastolic BPV. These results supplement the differential ambulatory blood pressure–lowering effects of these therapies in the CREOLE trial.

A Differential Response to Antihypertensive Therapy in African Men and Women: Insights From the CREOLE Trial

BACKGROUND

We sought to address the paucity of data to support the evidence-based management of hypertension to achieve optimal blood pressure (BP) control on a sex-specific basis in Africa.

METHODS

We undertook a post hoc analysis of the multicenter, randomized CREOLE (Comparison of Three Combination Therapies in Lowering Blood Pressure in Black Africans) Trial to test the hypothesis that there would be clinically important differences in office BP control between African men and women. We compared the BP levels of 397 and 238 hypertensive women (63%, 50.9 ± 10.5 years) and men (51.2 ± 11.3 years) from 10 sites across sub-Saharan Africa who completed baseline and 6-month profiling according to their randomly allocated antihypertensive treatment.

RESULTS

Overall, 442/635 (69.6%) participants achieved an office BP target of <140/90 mm Hg at 6 months; comprising more women (286/72.0%) than men (156/65.5%) (adjusted odds ratio [OR] 1.59, 95% confidence interval [CI] 1.07-2.39; P = 0.023). Women randomized to amlodipine-hydrochlorothiazide (HCTZ) (adjusted OR 3.03, 95% CI 1.71-5.35; P < 0.001) or amlodipine-perindopril (adjusted OR 2.62, 95% CI 1.49-4.58; P = 0.01) were more likely to achieve this target compared with perindopril-HCTZ. Among men, there were no equivalent treatment differences-amlodipine-HCTZ (OR 1.54, 95% CI 0.76-3.12; P = 0.23) or amlodipine-perindopril (OR 1.32, 95% CI 0.65-2.67; P = 0.44) vs. perindopril-HCTZ. Among the 613 participants (97%) with 24-hour ambulatory BP monitoring, women had significantly lower systolic (124.1 ± 18.1 vs. 127.3 ± 16.9; P = 0.028) and diastolic (72.7 ± 10.4 vs. 75.1 ± 10.5; P = 0.007) BP levels at 6 months compared with men.

CONCLUSIONS

These data suggest clinically important differences in the therapeutic response to antihypertensive combination therapy among African women compared with African men.

Pharmacokinetic profile and safety of adjusted doses of darunavir/ritonavir with rifampicin in people living with HIV

BACKGROUND

Darunavir/ritonavir is better tolerated than lopinavir/ritonavir and has a higher genetic barrier to resistance. Co-administration with rifampicin has been contraindicated as a significant reduction in darunavir exposure is expected. This is a barrier to darunavir/ritonavir use where TB is endemic.

OBJECTIVES

To evaluate the safety and pharmacokinetic profile of adjusted doses of darunavir/ritonavir with rifampicin.

METHODS

Virally suppressed participants on second-line lopinavir/ritonavir-based ART were switched to darunavir/ritonavir 800/100 mg q24h. In sequence: rifampicin was added; the dose of ritonavir was escalated; and darunavir was increased (darunavir/ritonavir 1600/200 mg q24h and 800/100 mg q12h were given in randomized sequence with rifampicin). Darunavir plasma concentrations were measured on the seventh/last day of each treatment period. To prevent viral rebound, dolutegravir (50 mg q12h) was added during rifampicin administration and for 1 week thereafter. Clinical events, ALT and bilirubin were monitored every 2-3 days during rifampicin administration.

RESULTS

A total of 17/28 participants started study treatment. Six (35.3%) were withdrawn for symptomatic hepatitis with severe ALT elevations, developing after 9-11 days of rifampicin and 2-4 days of ritonavir 200 mg. The study was stopped prematurely due to this high rate of hepatotoxicity. Only four participants completed the study. All hepatotoxicity resolved on withdrawal of study treatment. All participants were successfully re-established on their lopinavir/ritonavir-based regimen. After doubling the darunavir/ritonavir doses on rifampicin, darunavir pre-dose concentrations approached those on standard doses without rifampicin for q12h doses, but not for q24h doses.

CONCLUSIONS

Adjusted doses of darunavir/ritonavir with rifampicin had unacceptable risk of hepatotoxicity. Darunavir trough concentrations were markedly reduced with the daily adjusted dose.

Artificial intelligence-derived 3-Way Concentration-dependent Antagonism of Gatifloxacin, Pyrazinamide, and Rifampicin During Treatment of Pulmonary Tuberculosis

Background

In the experimental arm of the OFLOTUB trial, gatifloxacin replaced ethambutol in the standard 4-month regimen for drug-susceptible pulmonary tuberculosis. The study included a nested pharmacokinetic (PK) study. We sought to determine if PK variability played a role in patient outcomes.

Methods

Patients recruited in the trial were followed for 24 months, and relapse ascertained using spoligotyping. Blood was drawn for drug concentrations on 2 separate days during the first 2 months of therapy, and compartmental PK analyses was performed. Failure to attain sustained sputum culture conversion at the end of treatment, relapse, or death during follow-up defined therapy failure. In addition to standard statistical analyses, we utilized an ensemble of machine-learning methods to identify patterns and predictors of therapy failure from among 27 clinical and laboratory features.

Results

Of 126 patients, 95 (75%) had favorable outcomes and 19 (15%) failed therapy, relapsed, or died. Pyrazinamide and rifampicin peak concentrations and area under the concentration-time curves (AUCs) were ranked higher (more important) than gatifloxacin AUCs. The distribution of individual drug concentrations and their ranking varied significantly between South African and West African trial sites; however, drug concentrations still accounted for 31% and 75% of variance of outcomes, respectively. We identified a 3-way antagonistic interaction of pyrazinamide, gatifloxacin, and rifampicin concentrations. These negative interactions disappeared if rifampicin peak concentration was above 7 mg/L.

Conclusions

Concentration-dependent antagonism contributed to death, relapse, and therapy failure but was abrogated by high rifampicin concentrations. Therefore, increasing both rifampin and gatifloxacin doses could improve outcomes.

Clinical Trials Registration

NCT00216385.

Gatifloxacin Pharmacokinetics/Pharmacodynamics-based Optimal Dosing for Pulmonary and Meningeal Multidrug-resistant Tuberculosis

Background

Gatifloxacin is used for the treatment of multidrug-resistant tuberculosis (MDR-TB). The optimal dose is unknown.

Methods

We performed a 28-day gatifloxacin hollow-fiber system model of tuberculosis (HFS-TB) study in order to identify the target exposures associated with optimal kill rates and resistance suppression. Monte Carlo experiments (MCE) were used to identify the dose that would achieve the target exposure in 10000 adult patients with meningeal or pulmonary MDR-TB. The optimal doses identified were validated using probit analyses of clinical data from 2 prospective clinical trials of patients with pulmonary and meningeal tuberculosis. Classification and regression-tree (CART) analyses were used to identify the gatifloxacin minimum inhibitory concentration (MIC) below which patients failed or relapsed on combination therapy.

Results

The target exposure associated with optimal microbial kill rates and resistance suppression in the HFS-TB was a 0-24 hour area under the concentration-time curve-to-MIC of 184. MCE identified an optimal gatifloxacin dose of 800 mg/day for pulmonary and 1200 mg/day for meningeal MDR-TB, and a clinical susceptibility breakpoint of MIC ≤ 0.5 mg/L. In clinical trials, CART identified that 79% patients failed therapy if MIC was >2 mg/L, but 98% were cured if MIC was ≤0.5 mg/L. Probit analysis of clinical data demonstrated a >90% probability of a cure in patients if treated with 800 mg/day for pulmonary tuberculosis and 1200 mg/day for meningeal tuberculosis. Doses ≤400 mg/day were suboptimal.

Conclusions

Gatifloxacin doses of 800 mg/day and 1200 mg/day are recommended for pulmonary and meningeal MDR-TB treatment, respectively. Gatifloxacin has a susceptible dose-dependent zone at MICs 0.5-2 mg/L.

Quality assurance of rifampicin-containing fixed-drug combinations in South Africa: dosing implications

SETTING:

Rifampicin (RMP) drives treatment response in drug-susceptible tuberculosis. Low RMP concentrations increase the risk of poor outcomes, and drug quality needs to be excluded as a contributor to low RMP exposure.

OBJECTIVES AND DESIGN:

We performed an open-label, three-way cross-over study of three licensed RMP-containing formulations widely used in South Africa to evaluate the bioavailability of RMP in a two-drug fixed-dose combination tablet (2FDC) and a four-drug FDC (4FDC) against a single-drug reference. RMP dosed at 600 mg was administered 2 weeks apart in random sequence. Plasma RMP concentrations were measured pre-dose and 1, 2, 3, 4, 6, 8 and 12 h post-dose. The area under the concentration-time curve (AUC_0–12) of the FDCs was compared to the single drug reference. Simulations were used to predict the impact of our findings.

RESULTS:

Twenty healthy volunteers (median age 22.8 years, body mass index 24.2 kg/m²) completed the study. The AUC_0–12 of the 4FDC/reference (geometric mean ratio [GMR] 78%, 90%CI 69–89) indicated an average 20% reduction in RMP bioavailability in the 4FDC. The 2FDC/reference (GMR 104%, 90%CI 97–111) was bioequivalent. Simulations suggested dose adjustments to compensate for the poor bioavailability of RMP with the 4FDC, and revised weight-band doses to prevent systematic underdosing of low-weight patients.

CONCLUSION:

Post-marketing surveillance of in vivo bioavailability of RMP and improved weight band-based dosing are recommended.

Comparison of Dual Therapies for Lowering Blood Pressure in Black Africans

BACKGROUND

The prevalence of hypertension among black African patients is high, and these patients usually need two or more medications for blood-pressure control. However, the most effective two-drug combination that is currently available for blood-pressure control in these patients has not been established.

METHODS

In this randomized, single-blind, three-group trial conducted in six countries in sub-Saharan Africa, we randomly assigned 728 black patients with uncontrolled hypertension (≥140/90 mm Hg while the patient was not being treated or was taking only one antihypertensive drug) to receive a daily regimen of 5 mg of amlodipine plus 12.5 mg of hydrochlorothiazide, 5 mg of amlodipine plus 4 mg of perindopril, or 4 mg of perindopril plus 12.5 mg of hydrochlorothiazide for 2 months. Doses were then doubled (10 and 25 mg, 10 and 8 mg, and 8 and 25 mg, respectively) for an additional 4 months. The primary end point was the change in the 24-hour ambulatory systolic blood pressure between baseline and 6 months.

RESULTS

The mean age of the patients was 51 years, and 63% were women. Among the 621 patients who underwent 24-hour blood-pressure monitoring at baseline and at 6 months, those receiving amlodipine plus hydrochlorothiazide and those receiving amlodipine plus perindopril had a lower 24-hour ambulatory systolic blood pressure than those receiving perindopril plus hydrochlorothiazide (between-group difference in the change from baseline, -3.14 mm Hg; 95% confidence interval [CI], -5.90 to -0.38; P = 0.03; and -3.00 mm Hg; 95% CI, -5.8 to -0.20; P = 0.04, respectively). The difference between the group receiving amlodipine plus hydrochlorothiazide and the group receiving amlodipine plus perindopril was -0.14 mm Hg (95% CI, -2.90 to 2.61; P=0.92). Similar differential effects on office and ambulatory diastolic blood pressures, along with blood-pressure control and response rates, were apparent among the three groups.

CONCLUSIONS

These findings suggest that in black patients in sub-Saharan Africa, amlodipine plus either hydrochlorothiazide or perindopril was more effective than perindopril plus hydrochlorothiazide at lowering blood pressure at 6 months. (Funded by GlaxoSmithKline Africa Noncommunicable Disease Open Lab; CREOLE ClinicalTrials.gov number, NCT02742467.).

Rationale and design of the comparison of 3 combination therapies in lowering blood pressure in black Africans (CREOLE study): 2 × 3 factorial randomized single-blind multicenter trial

BACKGROUND

Current hypertension guidelines recommend the use of combination therapy as first-line treatment or early in the management of hypertensive patients. Although there are many possible combinations of blood pressure(BP)-lowering therapies, the best combination for the black population is still a subject of debate because no large randomized controlled trials have been conducted in this group to compare the efficacy of different combination therapies to address this issue.

METHODS

The comparison of 3 combination therapies in lowering BP in the black Africans (CREOLE) study is a randomized single-blind trial that will compare the efficacy of amlodipine plus hydrochlorothiazide versus amlodipine plus perindopril and versus perindopril plus hydrochlorothiazide in blacks residing in sub-Saharan Africa (SSA). Seven hundred two patients aged 30-79 years with a sitting systolic BP of 140 mm Hg and above, and less than 160 mm Hg on antihypertensive monotherapy, or sitting systolic BP of 150 mm Hg and above, and less than 180 mm Hg on no treatment, will be centrally randomized into any of the 3 arms (234 into each arm). The CREOLE study is taking place in 10 sites in SSA, and the primary outcome measure is change in ambulatory systolic BP from baseline to 6 months. The first patient was randomized in June 2017, and the trial will be concluded by 2019.

CONCLUSIONS

The CREOLE trial will provide unique information as to the most efficacious 2-drug combination in blacks residing in SSA and thereby inform the development of clinical guidelines for the treatment of hypertension in this subregion.

Bioavailability of two licensed paediatric rifampicin suspensions: implications for quality control programmes

SETTING

To assess the revised World Health Organization-recommended dose of 10-20 mg/kg rifampicin (RMP), we studied the steady state pharmacokinetics of RMP in South African children who received standard treatment for drug-susceptible tuberculosis (TB).

OBJECTIVE

To determine the formulation effect on the pharmacokinetics of RMP.

DESIGN

RMP plasma concentrations were characterised in 146 children (median age 1.4 years, range 0.2-10.2). The morning dose on the day of the pharmacokinetic evaluation was administered as one of two RMP single-drug oral suspensions.

RESULTS

While one formulation achieved 2 h concentrations in the range of those observed in adults (median 6.54 mg/l, interquartile range [IQR] 4.47-8.84), the other attained a median bioavailability of only 25% of this, with a median 2 h concentration of 1.59 mg/l (IQR 0.89-2.38).

CONCLUSION

RMP is a key drug for the treatment of TB. It is critical that the quality of RMP suspensions used to treat childhood TB is ensured.

Grain sizes, surface areas, and porosities of vapor-deposited H2O ices used to simulate planetary icy surfaces

Mean grain sizes and specific surface areas (SSAs) of ice substrates formed by vapor deposition at low temperatures are of importance in simulating external surfaces of icy satellites in the solar system. Environmental scanning electron microscopy (ESEM) was used to obtain granule sizes and to observe the phase of ice granules prepared on borosilicate, silicon, and metallic plates. Ices prepared at a temperature lower than 140 K appear to be amorphous, and their granule sizes are typically submicrometer. At slightly warmer temperatures, near 180-200 K, ice films are composed of either hexagonal or cubic granules with sizes up to a few micrometers. When briefly annealed to even warmer temperatures, ice granule sizes approach approximately 10 microm. SSAs of ice substrates were determined from BET (Brunauer, Emmett, and Teller) analysis of gas adsorption isotherms in the temperature range from 83.5 to 261 K. SSAs decrease drastically from 102 m2/g at 83.5 K to 0.87 m2/g at 150 K and further decrease slowly to 0.22 m2/g at 261 K, suggesting that the transition from amorphous to crystalline forms occurs at approximately 150 K. The overall decrease in SSAs is primarily due to metamorphism and sintering. These results are comparable to recent field and laboratory measurements. Possible implications for theoretical models of icy satellites of outer planets using remote sensing techniques are also discussed.

Prometheus: Io's wandering plume

Unlike any volcanic behavior ever observed on Earth, the plume from Prometheus on Io has wandered 75 to 95 kilometers west over the last 20 years since it was first discovered by Voyager and more recently observed by Galileo. Despite the source motion, the geometric and optical properties of the plume have remained constant. We propose that this can be explained by vaporization of a sulfur dioxide and/or sulfur "snowfield" over which a lava flow is moving. Eruption of a boundary-layer slurry through a rootless conduit with sonic conditions at the intake of the melted snow can account for the constancy of plume properties.

Near-infrared spectroscopy and spectral mapping of Jupiter and the Galilean satellites: results from Galileo's initial orbit

The Near Infrared Mapping Spectrometer performed spectral studies of Jupiter and the Galilean satellites during the June 1996 perijove pass of the Galileo spacecraft. Spectra for a 5-micrometer hot spot on Jupiter are consistent with the absence of a significant water cloud above 8 bars and with a depletion of water compared to that predicted for solar composition, corroborating results from the Galileo probe. Great Red Spot (GRS) spectral images show that parts of this feature extend upward to 240 millibars, although considerable altitude-dependent structure is found within it. A ring of dense clouds surrounds the GRS and is lower than it by 3 to 7 kilometers. Spectra of Callisto and Ganymede reveal a feature at 4. 25 micrometers, attributed to the presence of hydrated minerals or possibly carbon dioxide on their surfaces. Spectra of Europa's high latitudes imply that fine-grained water frost overlies larger grains. Several active volcanic regions were found on Io, with temperatures of 420 to 620 kelvin and projected areas of 5 to 70 square kilometers.