Developing biomarker assays to accelerate tuberculosis drug development: defining target product profiles.

Drug development for tuberculosis is hindered by the methodological limitations in the definitions of patient outcomes, particularly the slow organism growth and difficulty in obtaining suitable and representative samples throughout the treatment. We developed target product profiles for biomarker assays suitable for early-phase and late-phase clinical drug trials by consulting subject-matter experts on the desirable performance and operational characteristics of such assays for monitoring of tuberculosis treatment in drug trials. Minimal and optimal criteria were defined for scope, intended use, pricing, performance, and operational characteristics of the biomarkers. Early-stage trial assays should accurately quantify the number of viable bacilli, whereas late-stage trial assays should match the number, predict relapse-free cure, and replace culture conversion endpoints. The operational criteria reflect the infrastructure and resources available for drug trials. The effective tools should define the sterilising activity of the drug and lower the probability of treatment failure or relapse in people with tuberculosis. The target product profiles outlined in this Review should guide and de-risk the development of biomarker-based assays suitable for phase 2 and 3 clinical drug trials.

Point-of-Care COVID-19 Antigen Testing in Exposed German Healthcare Workers-A Cost Model.

BACKGROUND: Hospital staffing shortages are again (mid-year 2021) becoming a significant problem as the number of positive COVID-19 cases continues to increase worldwide. OBJECTIVE: To assess the costs of sending HCW into quarantine (Scenario 1) from the hospital's and the taxpayer's perspective versus the costs arising from implementing point-of-care COVID-19 antigen testing (POCT) for those staff members who, despite learning that they have been exposed to hospital patients later found to be infected with COVID-19, continue to report to work (Scenario 2). METHODS: A mathematical model was built to calculate the costs of a sample-and-stay strategy for exposed healthcare workers (HCW) in Germany by utilizing a high-quality antigen fluorescent immunoassay (FIA), compared to the costs of quarantine. Direct costs and wage costs were evaluated from the hospital as well as from the taxpayer perspective assuming a SARS-CoV-2 infection prevalence of 10%. RESULTS: Serial POCT testing of exposed HCW in Germany (Scenario 2) who do not go into quarantine but continue to work during a post-exposure period of 14 days at their working place raises costs of EUR 289 (±20%: EUR 231 to EUR 346, rounded) per HCW at the expense of the employing hospital while the extra-costs to the taxpayer per exposed HCW are limited to EUR 16 (±20%: EUR 13 to EUR 19). In contrast, sending HCW into quarantine (Scenario 1) would result in costs of EUR 111 (±20%: EUR 89 to EUR 133) per exposed HCW for the hospital but EUR 2235 (±20%: EUR 1744 to EUR 2727) per HCW at the expense of the taxpayer. CONCLUSIONS: Monitoring exposed HCW who continued working by sequential POCT may considerably reduce costs from the perspective of the taxpayer and help mitigate personnel shortages in hospitals during pandemic COVID-19 waves.

Compassionate use of delamanid in adults and children for drug-resistant tuberculosis: 5-year update.

BACKGROUND: Although delamanid has been approved for the treatment of multidrug-resistant TB (MDR-TB) in numerous regions, in areas where it is not yet registered it can be accessed as part of salvage therapy (in particular for those patients with limited treatment options) via the Otsuka compassionate use programme. Here we present the analysis of interim treatment outcomes by 24 weeks of more than 200 MDR-TB patients globally who received delamanid under this programme. METHODS: We evaluated treatment efficacy with respect to culture negativity at 24 weeks, as well as the safety profile of delamanid, in an MDR-TB patient cohort treated under compassionate use between 2014 and 2019. RESULTS: Among patients who received delamanid as part of a multidrug regimen, 123 (61%) out of 202 had extensively drug-resistant TB (XDR-TB), 66 (33%) out of 202 had HIV co-infection and 34 (17%) out of 202 were children aged between 6 and 17 years. Of those patients who were culture positive at delamanid treatment initiation and who completed 24 weeks of delamanid treatment in combination with other anti-tuberculosis (TB) drugs, culture negativity was achieved in 116 (79%) out of 147 cases. The corresponding rates of culture negativity for patients with XDR-TB and HIV co-infection, as well as the paediatric subgroup were 69 (77%) out of 90, 44 (92%) out of 48 and 20 (80%) out of 25, respectively. QT interval prolongation was the most frequently observed serious adverse event and was reported in 8% of patients receiving delamanid. Overall, treatment safety outcomes did not reveal any new or unidentified risks. CONCLUSIONS: The use of delamanid combined with other active drugs has the potential to achieve high rates of culture negativity in difficult-to-treat drug-resistant TB cases, with a favourable safety profile.

Efficacy and safety of delamanid in combination with an optimised background regimen for treatment of multidrug-resistant tuberculosis: a multicentre, randomised, double-blind, placebo-controlled, parallel group phase 3 trial.

BACKGROUND: Delamanid is one of two recently approved drugs for the treatment of multidrug-resistant tuberculosis. We aimed to evaluate the safety and efficacy of delamanid in the first 6 months of treatment. METHODS: This randomised, double-blind, placebo-controlled, phase 3 trial was done at 17 sites in seven countries (Estonia, Latvia, Lithuania, Moldova, Peru, the Philippines, and South Africa). We enrolled eligible adults (>18 years) with pulmonary multidrug-resistant tuberculosis to receive, in combination with an optimised background regimen developed according to WHO and national guidelines, either oral delamanid (100 mg twice daily) for 2 months followed by 200 mg once daily for 4 months or placebo (same regimen). Patients were centrally randomised (2:1) and stratified by risk category for delayed sputum culture conversion. Primary outcomes were the time to sputum culture conversion over 6 months and the difference in the distribution of time to sputum culture conversion over 6 months between the two groups, as assessed in the modified intention-to-treat population. The trial is registered at ClinicalTrials.gov, number NCT01424670. FINDINGS: Between Sept 2, 2011, and Nov 27, 2013, we screened 714 patients, of whom 511 were randomly assigned (341 to delamanid plus optimised background regimen [delamanid group] and 170 to placebo plus optimised background regimen [placebo group]) and formed the safety analysis population. 327 patients were culture-positive for multidrug-resistant tuberculosis at baseline and comprised the efficacy analysis population (226 in the delamanid group and 101 in the placebo group). Median time to sputum culture conversion did not differ between the two groups (p=0·0562; modified Peto-Peto), with 51 days (IQR 29-98) in the delamanid group and 57 days (43-85) in the placebo group; the hazard ratio was 1·17 (95% CI 0·91-1·51, p=0·2157). 501 (98·0%) of 511 patients had at least one treatment-emergent adverse event. 136 (26·6%) of 511 patients had at least one serious treatment-emergent adverse event; the incidence was similar between treatment groups (89 [26·1%] of 341 patients for delamanid and 47 [27·6%] of 170 for placebo). Deaths related to treatment-emergent adverse events were similar between groups (15 [4·4%] of 341 for delamanid and six [3·5%] of 170 for placebo). No deaths were considered to be related to delamanid. INTERPRETATION: The reduction in median time to sputum culture conversion over 6 months was not significant in the primary analysis. Delamanid was well tolerated with a highly characterised safety profile. Further evaluation of delamanid is needed to determine its role in a rapidly evolving standard of care. FUNDING: Otsuka Pharmaceutical.

Cost effectiveness of treating multi-drug resistant tuberculosis by adding Deltyba™ to background regimens in Germany.

OBJECTIVE: To assess the cost-effectiveness of adding delamanid (Deltyba™) to a background regimen (BR) for treating multidrug-resistant tuberculosis (MDR-TB) in Germany. METHODS: The incremental cost-effectiveness of treating a cohort of MDR-TB patients, 38-years old on average, with Deltyba™ plus BR versus a five drug- BR regimen alone was compared in a Markov model over a period of 10 years. Cost per quality-adjusted life year (QALY) and disability-adjusted life years (DALY) were determined from a societal perspective. Recent data from a German cost calculation on MDR-TB were applied to the 24-month outcome results of patients participating in the placebo-controlled, phase II Otsuka's Trial 204. Costs and effectiveness were discounted at a rate of 3% and subjected to deterministic as well as probabilistic sensitivity analysis in a Monte Carlo simulation. RESULTS: Based on the current market prices the total discounted cost per patient on BR plus Deltyba™ was €142,732 compared to €150,909 for BR alone. The total discounted QALYs per patient were 8.47 for Deltyba™ versus 6.13 for BR alone. Accordingly, the addition of Deltyba™ proved to be dominant over the BR alone-strategy by simultaneously saving €8177 and gaining 2.34 QALYs. Deltyba™ was cost saving in 73% of probabilistic sensitivity analyses compared to BR alone and 100% cost effective at a willingness-to-pay (WTP) threshold of €10,000. CONCLUSIONS: Under conditions prevalent in Germany, Deltyba™ added to a five drug BR regimen is likely to be cost-saving compared to BR alone under a wide range of assumptions. Adding delamanid remained cost-effective when costs due to loss of productivity were excluded as the QALYs gained by lower lethality and a higher proportion of successfully treated patients outweighed the delamanid drug costs. These results strongly support the application of Deltyba™ in treating MDR-TB patients.

A pooled analysis of the durability and predictors of treatment response of cilostazol in patients with intermittent claudication.

Pharmacologic therapy for intermittent claudication in patients with peripheral artery disease (PAD) is limited. We aimed to determine the durability of cilostazol treatment response over time, treatment effects in various subpopulations, and long-term safety. This analysis pooled original data from nine randomized, controlled trials evaluating cilostazol in intermittent claudication, including 1258 subjects treated with cilostazol 100 mg bid. Analysis of covariance was used to compare differences in walking distance, and a pooled random-effects weighted mean difference in maximal walking distance (MWD) was determined. Temporal effects were analyzed by compiling data at 4-week intervals in studies of 24 weeks in duration. Cilostazol was associated with a 50.7% improvement from baseline in MWD compared with placebo (24.3%), with an absolute improvement of 42.1 meters greater than the improvement with placebo (p < 0.001) over a mean follow-up period of 20.4 weeks. Continued increases were demonstrated over the 24-week treatment period. These benefits were seen in all subgroups, after stratifying by age, sex, smoking status, duration of PAD, diabetes, hypertension, prior myocardial infarction, or beta-blocker use. Cilostazol did not increase the risk of all-cause mortality (RR 0.95 [0.68-1.35]). In conclusion, treatment with cilostazol achieves benefits in walking distance that are sustained at 24 weeks and observed irrespective of baseline clinical characteristics. Cilostazol demonstrated no increased risk of all-cause mortality.

Treating peripheral arterial disease in patients with diabetes.

Diabetes is associated with considerably higher risks of developing peripheral arterial disease (PAD) which, when it occurs, is more severe and progresses more rapidly than in nondiabetics. Early detection of PAD in the diabetic patient is therefore important, but may be complicated by the presence of neuropathy and calcification of the arteries such that ischaemic symptoms are not felt by the patient and ankle pressures are not reduced. Toe pressures are an alternative diagnostic tool in these patients. Good glycaemic control, while an essential part of diabetes management, does not appear to bring more than modest benefits in preventing the peripheral vascular complications of diabetes. Therefore, attention to other risk factors is needed. Treatment with the phosphodiesterase III inhibitor, cilostazol, has been shown to improve walking distances significantly in diabetes patients with intermittent claudication and also appears to improve plasma lipid profiles. Further, cilostazol has an antiplatelet action, which may prove to be of benefit in diabetes because hyperglycaemia is associated with increased platelet aggregability. Revascularization in diabetes patients with critical leg ischaemia is complex and associated with poorer outcomes than in non-diabetes patients. While surgical revascularization has better patency rates, in patients at high risk of surgical complications, percutaneous transluminal angioplasty may be a better option.

Cilostazol treatment of claudication in diabetic patients.

OBJECTIVE: To compare the efficacy and safety of cilostazol in diabetic and non-diabetic patients from eight (six placebo- and two active-controlled) randomised, double-blind phase III trials. DESIGN: We only included patients from the trial data set receiving cilostazol 100 mg twice daily (216 diabetic/599 non-diabetic) or placebo (220/616). Efficacy was measured by absolute claudication distance (ACD), using standard treadmill exercise protocols. RESULTS: Among diabetic and non-diabetic patients, cilostazol was superior to placebo (estimated treatment effect 1.15, 95% confidence interval, 1.05-1.25, p = 0.001; and 1.24, 1.18-1.31, p < 0.0001, respectively). There was no statistical difference in response between diabetic and non-diabetic subjects. In the efficacy analysis, cilostazol-treated diabetic subjects with the lowest baseline ACD (but not those with greater baseline ACD) walked approximately 34% farther than at baseline, whereas their non-diabetic counterparts walked 23% farther. There was no significant difference in the adverse event profile of the diabetic and non-diabetic patients on cilostazol. No excess haemorrhagic events occurred in cilostazol-treated diabetic patients. Trial duration varied from 12 to 24 weeks. CONCLUSIONS: Diabetic and non-diabetic patients with intermittent claudication respond favourably to cilostazol, with no significant difference in their overall response. Diabetic individuals with the most severe claudication respond better than those less affected, but the response of non-diabetic patients increases as baseline ACD increases. Adverse event incidence was comparable in the two populations, although diabetic patients might be expected to experience greater morbidity. Cilostazol is a safe and effective treatment for claudication in diabetic and non-diabetic populations.