Clinical efficacy studies design

The PRO ACT-11 trial was designed to assess the clinical efficacy and safety of lA r-pro-UK. In this study, 180 patients were enrolled in a 2 1 randomization scheme to receive either 9 mg lA r-pro-UK plus 4 hours of low-dose IV heparin, or low-dose IV heparin alone. The primary clinical outcome, the proportion of patients with slight or no disability at 90 days (mRS of < 2), was achieved in 40% of the 121 patients in the r-pro-UK treatment group, compared to 25% of the 59 patients in the control group (absolute benefit 15%, relative benefit 58%, number need to treat = 7 p = 0.04). The recanalization rate (TlMl 2 and 3) was 66% for the r-pro-UK group and 18% for the control group (p < 0.001). Symptomatic ICH within 24 hours occurred in 10% of r-pro-UK patients and 2% of control patients (p = 0.06). All symptomatic ICHs occurred in patients with a baseline NIHSS... 

Table 2A. Summary of clinical studies of the efficacy of rifaximin in the treatment of acute infectious diarrhea study design...

A good clinical trial is designed to take account of the variability in response (either efficacy or adverse event) that is expected when a new active drug is tested. This response depends on an individual s genetic make-up, and on a number of environmental factors, such as disease state, other drugs and age. The size of the trial and the selection of study subjects are carefully determined to reduce the variability in response to a minimum (i.e. to maximise the sensitivity of the trial) so that the trial endpoints can be determined with as much certainty as possible. 

We apply our classification of study designs throughout the text to help the clinician interpret the quality of results from clinical trials. Further, we give the critical reader a perspective on the depth and validity of the available data. Most studies in our analyses of drug efficacy are class I or II, and if not, we discuss the studies accordingly. 

As far as the direct comparison between SLIT and SCIT is concerned there is a single double-blind double-dummy study published as a full paper [37]. It showed that SLIT had a clinical efficacy superimposable to SCIT (symptoms and need for drugs), but that SLIT was better accepted and tolerated by the patients. Another well-designed rigorous double-dummy trial with birch pollen extract has recently been published in abstract form [38], The study showed that SLIT and injection IT had a similar efficacy, but only with SCIT did systemic side effects of grade III and IV appear, whereas SLIT was comparable to placebo. 

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