• Question: Why is it so long to find new treatments against the multidrug resistant bacteria ?

    Asked by Bap06 to Ceri, Marikka, Matt, Rob, Sally on 18 Nov 2014.
    • Photo: Ceri Dare

      Ceri Dare answered on 18 Nov 2014:

      Because new medicines have to go through a lot of testing. First we have to find a molecule which may be useful, then test it in a test tube, then animal testing, then human testing for safety, then human testing to find out if it works in people. All these tests are very careful and take a very long time. Most molecules will fail at some stage – it is quite easy to kill bacteria in a test tube, but much more difficult to make a medicine which can be safely taken by humans.

    • Photo: Sally Cutler

      Sally Cutler answered on 18 Nov 2014:

      It takes years of safety and efficacy testing to get new antibiotics to the marketplace and many fall by the wayside. Multidrug resistant organisms give us far more of a challenge as the usual targets often will not work.

    • Photo: Robert Hampson

      Robert Hampson answered on 19 Nov 2014:

      If we start off with me finding a promising molecule (called a hit). We have to do a lot of development on this hit. Firstly we have to verify how it produces the results it is getting, we have to try to ascertain its mechanism of action, and we try to find out as much about it as possible. Then we develop biological tools to allow us to easily assess any given molecules action on this target. Once we have reached this stage we can really begin developing the molecules.

      While developing the hit we have to make it a stronger molecule (hits are often fairly weak), we have to improve its solubility (hits are often quite oily and don’t dissolve very well), we have to try to avoid weak chemical groups which may fall apart in biological systems and any groups known to be toxic, we should also generally try to make the hit more stable (many hits fall apart quickly over time). If we manage all these things using chemistry and biology then we have what is called a lead.

      This lead molecule is then forwarded to further tests to make sure it is not toxic to mammalian cells, that it still actually kills bacteria, and that it has no strange side affects in multiple different mammalian cell lines.

      Once all these have been confirmed, the the molecule can go to what is called pre-clinical testing. This is essentially a load of different animal testing to test lots of different things. Testing that it actually kills the bacteria, that it has a suitable break down time (i.e. you don’t have to take the drug every 10 minutes or it doesn’t stay inside you for 20 years), that it doesn’t have weird side affects, and that it isn’t toxic to animals. At this stage, the drug must also be more effective than anything else on the market. If it is not, why would anyone buy it.

      Once all this has happened, the molecule can move to clinical testing, which is testing in humans. This part of the process alone can take 5-7 years and contains multiple phases. From initial small screening for toxicity to final large scale testing for minor side effects and efficacy.

      Basically, it takes so long because the initial science is difficult and takes a long time and also to make sure everything is right and safe before loads of people start taking the final product!

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