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The gulf between theory and practice: why medicines do not always work as expected

(Vienna, 14th July 2011) Medicines don't work. Or they cause undesirable side effects. An article created with the support of the MedUni Vienna in the current edition of the scientific journal "Nature Reviews Drug Discovery" now offers solutions for this common medical problem.

The effect and possible side-effects of medicines are stringently tested before they are approved. During these in-depth tests, the drug regulatory authorities ensure that the benefits of a drug outweigh the risks. However there are more and more cases in which medicines do not achieve the results stated during the approval process and expected from the studies. Often, the effect of drugs in everyday medical situations is less than expected, or undesirable side effects - sometimes severe ones - can occur. This doesn't need to be the case, as an international publication which appeared recently in "Nature Reviews Drug Discovery" and which also involved the MedUni Vienna's University Department of Clinical Pharmacology, shows.

Medicines don't always deliver what they promise
The scientists investigated the "efficacy-effectiveness gap", or the gulf between theory and practice, in the use of medicines. Brigitte Blöchl-Daum, Deputy Head of the University Department of Clinical Pharmacology at the MedUni Vienna and corresponding author of the study, explains what the study is about: "First of all, we wanted to show why medicines don't always deliver what they promise in everyday clinical situations, and secondly, how we can resolve this problem."
Numerous causes responsible for different effects of medicines

The authors of the study were able to determine multiple causes for the different effects of medicines. The bottom line, as it were, is each person's unique biology and individual genes.  Says Blöchl-Daum: "To put it simply, every one of us is different, and this is why we can respond differently to a particular drug." Added to this are further factors that are directly associated with the individual. These include in particular concomitant illnesses, factors such as body mass index or age and the taking of other - including herbal - remedies. "Another problem might seem inconsequential, but it is an important one - namely taking the wrong dose. Medications cannot work if they're not taken. Or they work differently if they're taken to excess. And ultimately, the wrong drugs are simply being prescribed time and time again", says Blöchl-Daum.
Two ways of closing the "efficacy-effectiveness gap"

If the expectations (efficacy) do not match reality (effectiveness), there are two ways of closing this gap: Either the expectations are reduced to a realistic level, i.e. the drug regulatory authorities demand effectiveness trials before approval - i.e. studies that correspond to clinical reality. Or they take reality to the level of expectations. This would mean that medicines can only be prescribed and taken by the patient in a manner that corresponds exactly to the requirements of the approval. 

Recommendation by the study: The right drug, at the right dose, at the right time, to the right patient

If the scientific validity of the studies is confirmed, and yet a significant "efficacy-effectiveness gap" still remains, the study claims that there is a medical care problem. For Blöchl-Daum, two questions are crucial in this context: "Who is suitable for a particular medicine? And at what time, and in what dose? From our perspective, there is a range of solutions for this. Biomarkers can help to create an individual benefits/risk profile. A medicine should also be given first to those people who are deemed most likely to benefit from it. Ideally, there would be close collaboration between the approval authorities, the organisations funding the drugs and the individuals prescribing them, along with a tiered approval process for medicines."

Accordingly, the drug regulatory authorities could help to improve the quality of prescribing. Possible measures might include risk management plans and rapid access to all of the essential information, e.g. through an effectiveness label, i.e. a clear indicator of the drug's effectiveness. In order to ensure that the medicines are taken correctly, the scientists also recommend new approaches. For example, reminders to take medication by a SMS text message, the use of medicine packaging, reminding patients with light or sound, or edible sensors that trigger a signal on contact with gastric acid that is stored and transmitted to allow an appropriate response to be triggered.

Simple opportunity to improve public health
Blöchl-Daum explains the logic of such innovations as follows: "The development of a new medicine is an expensive and time-consuming process. This is why all measures that improve effectiveness and take it to the level of efficacy are a thoroughly worthwhile investment. Public health can therefore be improved relatively easily.

“Bridging the efficacy-effectiveness gap: a regulator's perspective on addressing variability of drug response." Eichler HG, Abadie E, Breckenridge A, Flamion B, Gustafsson LL, Leufkens H, Rowland M, Schneider CK, Bloechl-Daum B. Nat Rev Drug Discov. 2011 Jul 1;10(7):495-506.