Biological drugs for the treatment of rheumatoid arthritis by the subcutaneous route: interpreting efficacy data to assess statistical equivalence

BACKGROUND

No equivalence analysis has yet been conducted on the effectiveness of biologics in rheumatoid arthritis. Equivalence testing has a specific scientific interest, but can also be useful for deciding whether acquisition tenders are feasible for the pharmacological agents being compared.

METHODS

Our search covered the literature up to August 2014. Our methodology was a combination of standard pairwise meta-analysis, Bayesian network meta-analysis and equivalence testing. The agents examined for their potential equivalence were etanercept, adalimumab, golimumab, certolizumab, and tocilizumab, each in combination with methotrexate (MTX). The reference treatment was MTX monotherapy. The endpoint was ACR50 achievement at 12 months. Odds ratio was the outcome measure. The equivalence margins were established by analyzing the statistical power data of the trials.

RESULTS

Our search identified seven randomized controlled trials (2846 patients). No study was retrieved for tocilizumab, and so only four biologics were evaluable. The equivalence range was set at odds ratio from 0.56 to 1.78. There were 10 head-to-head comparisons (4 direct, 6 indirect). Bayesian network meta-analysis estimated the odds ratio (with 90% credible intervals) for each of these comparisons. Between-trial heterogeneity was marked. According to our results, all credible intervals of the 10 comparisons were wide and none of them satisfied the equivalence criterion. A superiority finding was confirmed for the treatment with MTX plus adalimumab or certolizumab in comparison with MTX monotherapy, but not for the other two biologics.

CONCLUSION

Our results indicate that these four biologics improved the rates of ACR50 achievement, but there was an evident between-study heterogeneity. The head-to-head indirect comparisons between individual biologics showed no significant difference, but failed to demonstrate the proof of no difference (i.e. equivalence). This body of evidence presently precludes any option of undertaking competitive tenderings for the procurement of these agents.

New oral anticoagulants in acute coronary syndrome: is there any advantage over existing treatments?

BACKGROUND

After an acute coronary syndrome, dual antiplatelet therapy with clopidogrel plus aspirin is still a standard of care, but several new approaches have been investigated.

OBJECTIVES

The present study re-examined the studies published thus far on this topic to evaluate the effectiveness of dual antiplatelet therapy in comparison to some of these new approaches (mainly, ticagrelor + aspirin and dual therapy plus a new oral anticoagulant [NOAC]; i.e., "triple therapy").

MATERIALS AND METHODS

The clinical material was directly derived from that reported in recent meta-analyses. Our re-analysis relied on standard equivalence methods in which interpretation is based on Relative Risks (RRs) along with their 95% Confidence Intervals (CI). The equivalence margins employed in our statistical testing were directly derived from those reported in randomized studies.

RESULTS

The equivalence margins were initially set at RR ranging from 0.775 to 1.29. According to these margins, triple therapy based on any NOAC proved to be superior to dual therapy alone, but at the same time demonstrated its equivalence with dual therapy. The results for apixaban-based triple therapy were inconclusive (not superior, not not-inferior, not equivalent and, of course, not inferior to the controls). Those for rivaroxaban-based triple therapy showed that this combination treatment was superior to dual therapy alone and failed to meet the criterion of equivalence. In the comparison between rivaroxaban-based triple therapy and ticagrelor + aspirin, the RR was 1 and its 95% CI remained within a post-hoc margin of ± 15%.

CONCLUSIONS

Even if one considers the most effective NOAC in combination with clopidogrel + ticagrelor, this triple therapy is not more effective than ticagrelor + aspirin. On the other hand, the increased risk of bleeding with triple regimens is well demonstrated. We therefore conclude that these triple regimens did not play any important roles in the patients experiencing an acute coronary syndrome.

Anti-reabsorptive agents in women with osteoporosis: determining statistical equivalence according to evidence-based methods

BACKGROUND

In the present study, we undertook an equivalence analysis on the effectiveness of the main anti-reabsorptive agents indicated for women with osteoporosis.

METHODS

Our methodology was a combination of meta-analysis (both pair-wise meta-analysis and network meta-analysis) and equivalence testing. The end-point was the incidence on new vertebral fractures. The anti-reabsorptive agents examined included alendronate, zoledronate, ibandronate, risedronate, and denosumab.

RESULTS

Our analysis involved nine randomized trials. Ten head-to-head indirect comparisons were examined through network meta-analysis and the respective values of RR were estimated. The 95 % confidence intervals for RR remained within the interval of a relative ±40 % variation for all comparisons that involved alendronate, risedronate, ibandronate, and denosumab. In contrast, the comparisons involving zoledronate satisfied a post hoc margin up to ±67 %.

CONCLUSION

Our results confirm that most of these anti-reabsorptive drugs (namely, alendronate, risedronate, ibandronate, and denosumab) are equivalent according to reasonable equivalence margins.

Testing the therapeutic equivalence of alogliptin, linagliptin, saxagliptin, sitagliptin or vildagliptin as monotherapy or in combination with metformin in patients with type 2 diabetes

BACKGROUND

In studying the therapeutic evidence of innovative drug treatments, increasing attention is being devoted to differentiating between results that indicate no significant differences among the treatments under examination ("no proof of difference") and results that demonstrate the therapeutic equivalence among the treatments ("proof of no difference").

AIM

Our analysis was aimed at evaluating the degree of therapeutic equivalence for dipeptidylpeptidase-4 (DPP-4) inhibitors given in type 2 diabetes as monotherapy or in combination with metformin.

METHODS

Equivalence was determined by developing a standard Forest plot that incorporated the information on margins previously reported in randomized trials on these agents. The end point was HbA1c change from baseline; the equivalence margin was set at ±0.25% change in HbA1c. The clinical material was obtained from a systematic review on this topic.

RESULTS

Given as monotherapy, linagliptin, sitagliptin, and vildagliptin (but not saxagliptin) met the equivalence criterion when compared with one another. Given in combination with metformin, linagliptin, saxagliptin, sitagliptin, and vildagliptin showed an equivalent effect whereas alogliptin did not satisfy the equivalence criterion.

CONCLUSIONS

Considering the most recent therapeutic guidelines, our results are of interest particularly as regards the information on DPP-4 inhibitors in combination with metformin. Four of the five DPP-4 inhibitors under examination clearly showed to have the same effectiveness; the fifth agent-alogliptin-failed to meet the equivalence criterion, but only because its superiority could not be excluded.

Meta-regression of treatments for metastatic colorectal cancer: Quantifying incremental benefit from 2000 to 2012

To evaluate the overall effectiveness of treatments for metastatic colorectal cancer, a meta-regression was undertaken in which randomized studies from 2000 to 2012 were evaluated and the temporal trend for both overall survival (OS) and progression-free survival (PFS) was determined. Our literature search was essentially based on PubMed but information sources were scanned. Trials were included if a fluoropyrimidine regimen was given to at least one arm and information on PFS and OS was available. Medians for OS and PFS were our end-points. Covariates included temporal trend, arm allocation and Kirsten rat sarcoma status. In analyzing 130 treatment arms identified through our literature search, meta-regression showed an improvement with time for both OS (P < 0.001) and PFS (P < 0.001). The increase in median OS was from 14.9 mo in 2000 to 18.8 mo in 2012. Likewise, the improvement in PFS was from 5.7 to 8.1 mo. Multivariate analysis confirmed these findings. A post-hoc multivariate analysis was focused on patient arms treated with bevacizumab (n = 17) or without bevacizumab (n = 113); the multivariate-adjusted improvement attributable to bevacizumab was 1.66 mo for OS (P = 0.071) and 1.59 mo for PFS (P = 0.002). Overall, our results indicate that OS and PFS have improved from 2000 to 2012 but the extent of this improvement is small and seems to have quite a questionable clinical relevance.

Dexmedetomidine vs propofol in intensive care unit patients

Dexmedetomidine is indicated as a sedative agent in intensive care units (ICUs). While several clinical trials and two meta-analyses have compared this agent with propofol or midazolam, the results were variable depending on the specific end-point (e.g., duration of mechanical ventilation, ICU mortality, maintaining a target depth of sedation, incidence of delirium episodes, length of hospital stay). Hence, the effectiveness of this new agent vs the comparators seems to be controversial. Trial sequential analysis (TSA) is a statistical technique that can estimate the optimal, cumulative number of patients that would be needed to generate a conclusive result. We therefore applied a TSA model to the most recent meta-analysis evaluating dexmedetomidine. A total of 10 randomized controlled trials were included in our analysis. According to our results, the comparison of dexmedetomidine vs propofol showed no proof of incremental effectiveness for the end-points of length of ICUs stay and incidence of delirium episodes. In contrast, futility (i.e., proof of no incremental effectiveness) was demonstrated for the end-point of mechanical ventilation. Hence, the results for the comparison of dexmedetomidine vs propofol were inconclusive for the first two end-points; on the other hand, conclusiveness was reached for the third end-point. We conclude that the place of dexmedetomidine in therapy of critically ill patients is very uncertain and further controlled trials are still needed.

Acute lymphoblastic leukemia in first complete remission: temporal trend of outcomes in studies comparing allogeneic transplant with autologous transplant or chemotherapy

In patients with acute lymphoblastic leukemia in first complete remission, several studies have compared allogeneic transplant with autologous transplant or chemotherapy. This material can be the basis for analyzing the temporal trend of outcomes. Our study was designed as a meta-regression focused on temporal trends and based on the endpoint of 5-year leukemia-free survival (5yLFS). Studies in which 5yLFS was determined in a patient group subjected to allogeneic transplant and in a control group (treated with autologous transplant and/or chemotherapy) were eligible for our meta-analysis. A standard literature search was carried out to identify pertinent studies. The results of included studies were submitted to an observational meta-analysis and to a meta-regression focused on two covariates (calendar year in which the study was conducted; percentage of high-risk patients). The endpoint of 5yLFS was separately assessed between allogeneic transplant and autologous transplant or chemotherapy. Our analysis included 14 studies that covered a period (1983 to 1999) in which patients were conditioned only with myeloablative conditioning and not with non-myeloablative ones. In the risk ratio (RR) analysis, the pooled outcome showed a significantly better profile for allogeneic transplantation (RR = 1.42; 95 % confidence interval (CI), 1.22 to 1.65). Separate analysis of the two treatment options found a pooled 5yLFS of 45 % (95 % CI, 38 to 51 %) for allogeneic transplant vs 30 % (95 % CI, 23 to 37 %) for the controls. In meta-regression, the temporal trend analysis revealed that, in patients subjected to allogeneic transplant, the values of 5yLFS showed no significant change over the 16-year interval (p = 0.720); the same stability over time was found in the control group (p = 0.489). On the other hand, the percentage of high-risk patients influenced outcomes in both patient groups at levels of statistical significance (p = 0.014 and p = 0.045 in the allotransplant group and in the controls, respectively). Our results can represent a reference point for future analyses focused on patients treated in more recent years.

Early and intermediate survival after transcatheter aortic valve implantation: systematic review and meta-analysis of 14 studies

BACKGROUND

Transcatheter aortic valve implants (TAVIs) is indicated as an alternative to surgical valve replacement for patients unfit for surgery. No systematic review has studied survival after 2 years and limited information is available on between-study heterogeneity.

OBJECTIVES

A systematic review and meta-analysis on intermediate survival after TAVI.

DATA SOURCES

PubMed, EMBASE, Scopus and references of selected articles.

STUDY ELIGIBILITY CRITERIA

Clinical studies evaluating TAVI, published between 2010 and 2012, reporting survival at 2 or more years.

PARTICIPANTS

About 3500 patients from 14 studies.

STUDY APPRAISAL AND SYNTHESIS METHODS

Proportion meta-analysis with 95% CI and heterogeneity assessment (I(2) and Cochran's Q). Meta-regression analysis was performed as well.

RESULTS

Pooled immediate postoperative death rate was 7.8% (95% CI 6.2% to 9.8%, I(2)=40.8%; Cochran's Q=97.7 with 92.9 df, p<0.0001) and stroke rate was 3.8% (95% CI 2.8% to 5.0%, I(2)=34.3%; Cochran's Q=96.5 with 92.9 df, p<0.0001). Pooled death rates at 1, 2 and 3 years were 23.2%, 31.0% and 38.6%, respectively. Among studies reporting on concomitant percutaneous coronary intervention, pooled death rates at 30 days, 1 year and 2 years were 6.3%, 17.8% and 25.8%, respectively.

LIMITATIONS

Although our analysis examined a total of about 3500 patients, only a minority of these were actually followed up after 2 years.

CONCLUSIONS

Pooled survival rates after TAVI (at 2 years: 69.0%; at 3 years: 61.4%) can be considered excellent, particularly in the light of the high-risk profile of this patient population. IMPLICATIONS OF KEY FINDINGS: The favourable intermediate outcome in patients subjected to TAVI seems to justify its use in patients unfit for surgery. Such pooled results indicate that TAVI is a valid alternative to surgical valve replacement, but lack of data on late durability after TAVI prevents its use in low-risk patients with long expectancy of life.