Building Robustness into Translational Research

Nonclinical studies form the basis for the decision whether to take a therapeutic candidate into the clinic. These studies need to exhibit translational robustness for both ethical and economic reasons. Key findings confirmed in multiple species have a greater chance to also occur in humans. Given the heterogeneity of patient populations, preclinical studies or at least programs comprising multiple studies need to reflect such heterogeneity, e.g., regarding strains, sex, age, and comorbidities of experimental animals. However, introducing such heterogeneity requires larger studies/programs to maintain statistical power in the face of greater variability. In addition to classic sources of bias, e.g., related to lack of randomization and concealment, translational studies face specific sources of potential bias such as that introduced by a model that may not reflect the full spectrum of underlying pathophysiology in patients, that defined by timing of treatment, or that implied in dosing decisions and interspecies differences in pharmacokinetic profiles. The balance of all these factors needs to be considered carefully for each study and program.

A prospective, randomized, placebo-controlled, double-blind trial about safety and efficacy of combined treatment with alteplase (rt-PA) and Cerebrolysin in acute ischaemic hemispheric stroke

BACKGROUND

The neurotrophic drug Cerebrolysin accelerated recovery and prevented acute neuronal damage in preclinical models of ischaemia. Previous clinical trials support therapeutic effects in stroke patients. The study investigated whether the combination with alteplase and Cerebrolysin is safe and can further reduce disability after acute ischaemic stroke.

METHODS

This placebo-controlled, double-blind trial involved 119 patients with acute ischaemic hemispheric stroke, randomly assigned to a combined treatment with alteplase plus Cerebrolysin or placebo (administered 1 h after thrombolytic treatment) starting within three-hours after onset of symptoms. A daily i.v. infusion of 30 ml Cerebrolysin or placebo was given for 10 consecutive days. Primary outcome was the modified Rankin Scale at day 90. A sequential design with interim analyses was applied.

RESULTS

The third interim analysis did not show a benefit in the modified Rankin Scale for Cerebrolysin on day 90 compared to placebo and the study was stopped. The National Institutes of Health Stroke Scale responder analysis (secondary outcome measure) showed significantly more patients with an improvement of 6 or more points (or a total score of 0 or 1) after two-, five-, 10, and 30 days in the Cerebrolysin group. Similar trends were observed for the modified Rankin Scale responder analysis without achieving statistical significance. There was no difference between treatment groups regarding adverse events.

CONCLUSIONS

The combination of Cerebrolysin with recombinant tissue-Plasminogen Activator is safe for treatment of acute ischaemic stroke but did not improve outcome at day 90. During the treatment period with Cerebrolysin (10 days), significantly more patients had a favourable response in neurological outcome measures (National Institutes of Health Stroke Scale) as compared to the placebo group.

An update on pharmacological approaches to neurodegenerative diseases

Neurodegenerative diseases are now generally considered as a group of disorders that seriously and progressively impair the functions of the nervous system through selective neuronal vulnerability of specific brain regions. Alzheimer's disease is the most common neurodegenerative disease, followed in incidence by Parkinson's disease; much less common are frontotemporal dementia, Huntington's disease, amyothrophic lateral sclerosis (Lou Gehrig's disease), progressive supranuclear palsy, spinocerebellar ataxia, Pick's disease and, lastly, prion disease. In this review, the authors intend to survey new drugs in different clinical phases but not in the preclinical or discovery stages nor already in the market, with new molecules aimed at interrupting or at attenuating different pathogenic pathways of neurodegeneration and/or at ameliorating symptoms. Drugs in different pharmacological phases are under study or are ready to be introduced into therapy for Alzheimer's disease, which display anti-beta-amyloid activity or nerve growth factor-like activity or anti-inflammatory properties. Other drugs possess mixed mechanisms of action, such as acetylcholinesterase inhibition and impairment of beta-amyloid formation through inhibition of beta-amyloid precursor protein synthesis and/or modulation of secretase activity. Other therapeutic approaches are based on immunotherapy, control of metal ions interactions with beta-amyloid and ensuing oxidative reactions as well as metabolic or hormonal regulation. The symptomatic therapy of motor behaviour in Parkinson's disease, based on l-DOPA, is registering adenosine A(2A) receptor antagonists, monoamine oxidase B inhibitors and ion channel modulators, as well as dopamine uptake inhibitors and glutamate AMPA receptor antagonists. There are also many other drugs involved, including astrocyte-modulating agents, 5-HT(1A) agonists and alpha(2)-adrenergic receptor antagonists, which are targeted at preventing or ameliorating Parkinson's disease-related or l-DOPA-induced dyskinesias. Huntington's disease therapy envisages a Phase III drug, LAX-101, which displays antiapoptotic properties by promoting membrane stabilisation and mitochondrial integrity. Other drugs with antioxidant and antiapoptotic steroid-like and neuroprotective activity are under investigation for the therapy of the less common neurodegenerative diseases.