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Disease is an inseparable part of life. We have advanced a long way in identifying and neutralising pathogens around us, but new ones crop up almost daily. Luckily, we have well developed processes and tools to help us fight diseases, new and old. Using biotechnology and its various branches, we can pinpoint the defining characteristics of every sickness and develop a cure which strikes at the right place with the right force.
Engineering new drugs is one way to do that, but a growing number of biotechnologists are turning to nature’s untapped resources. Indeed, more than half of the new medicines in the past decade were built around active components readily available on Earth; extracts from plants, oceanic invertebrates, and other species with the ability to cure. This is truly inspirational and an invitation for future exploration and testing.
Disease study models
Once a disease is discovered, there are many ways to go about pulling it apart and homing in on its weak spot. Cell cultures are a common first step: growing parallel cultures of healthy and diseased cells helps us observe how the pathogen affects the cell’s internal workings and protein expressions (which is also known as proteomics). Bioinformatics contains an ever-growing body of bio-data which can be used for cross-verification and hypothesis building when we deal with a new disease which bears similarities to other known conditions.
The different methods above help us identify the therapeutic target: the specific molecule in the human body which directly relates to the disease and which we want to manipulate in order to provide relief. Among the estimated 8,000 possible targets in the human body, most are proteins of various size and function. They are usually over or under-represented when a disease manifests itself, so the goal is to restore them to their normal number and function. In this, biotechnology mimics the large molecules our own bodies produce to maintain health – another testament to nature’s supreme mechanism. The downside of this process is that it is lengthy and complex. Pinpointing a good therapeutic target can take years of experimentation.
Once the target is acquired, we need a drug which produces the desired effect on it. The first choice is between a small-molecule compound (chemically engineered or natural) or a large-molecule biologic (genetically engineered). Each has particular strengths and weaknesses, and the choice depends on the nature of the target. For instance, compounds can easily pass through cell walls but require higher dosage, while biologics are better suited for extracellular targets and can be administered in less frequent dosings.
New drugs with auspicious effects on the therapeutic target are put through rigorous testing before human trials begin. clinical trials begin in the laboratory, where human cell lines are used to assess the compounds toxicity. First in human trials (Phase 1 trials) assess the treatments safety, and establish the ideal dosage range. At this stage in the trials, efficacy is not under scrutiny since healthy volunteers are used. Pharmacokinetics (how metabolization affects the treatment) and Pharmacodynamics (how the treatment affects the body) are monitored closely. Phase 1 trials are generally carried out with 20 – 80 volunteers. Before a new treatment is licensed and made available for prescription, it must pass through three phases of clinical trials. Each subsequent phase of the study is conducted with a larger number of volunteers than the one before.
Phase 2 trials require between 100 and 300 volunteers. Phase 3 studies the efficacy of the treatment and are carried out with volunteers who suffer with the ailment the treatment is intended to alleviate. Sample sizes for Phase 3 vary depending on the prevalence of the condition or ailment being targeted. Once the treatment is licensed and made available for doctors to prescribe, it will continue to be monitored on an ongoing basis by collating patient info. This occurs for as long as the treatment remains in use.
From drug to treatment
The complex process above sums up the long journey from test drug to treatment. It takes anywhere between 10 to 15 years to complete, but if a drug finally becomes a treatment, no time investment has been too large.
This guest post was authored by Nick Davison, Nick is passionate about environmental issues and medical advancement.