Global challenges Study Guide

The process of bringing a new medicine to market is long, complex, and highly regulated, typically taking many years and costing vast sums of money. It begins with the initial discovery phase, where scientists identify potential new drug compounds, often from natural sources like plants or microbes, or through synthesis in laboratories. This involves understanding disease mechanisms and looking for molecules that might interact with specific targets in the body to treat a condition. Once a promising compound is identified, it enters preclinical testing. This stage involves laboratory (in vitro) tests on cells and tissues, followed by tests on live animals (in vivo) to assess the drug's efficacy, toxicity, and safe dosage. Animal testing is crucial for understanding how the drug behaves in a whole living system before it can be given to humans.

If a drug shows promise in preclinical trials, it moves to clinical trials, which are conducted on human volunteers. Clinical trials are carefully phased. Phase 1 trials involve a small group of healthy volunteers to determine the drug's safety, effective dosage range, and how the body absorbs, distributes, metabolises, and excretes it. Phase 2 trials involve a larger group of patients with the target condition to assess the drug's effectiveness and further monitor side effects. Phase 3 trials are even larger, involving hundreds or thousands of patients, often comparing the new drug to existing treatments or a placebo to confirm its effectiveness, monitor long-term side effects, and gather data on different patient populations. Before a drug can be made available to the public, all the data from these trials are thoroughly reviewed by regulatory bodies to ensure the medicine is safe and effective for its intended use. Even after approval, drugs are continually monitored for any new or rare side effects once they are widely used by the public.

Non-communicable diseases (NCDs) are illnesses that cannot be spread from person to person. Unlike infectious diseases caused by pathogens, NCDs result from a combination of different factors. Most NCDs are not caused by a single, isolated factor, but rather by the interaction of several factors working together. These factors can broadly be categorised into genetic predispositions, lifestyle choices, and environmental influences.

Genetic factors include inherited traits that may make an individual more susceptible to certain conditions, such as some forms of diabetes or heart disease. While genes can increase risk, they rarely act alone. Lifestyle factors are choices an individual makes, such as diet, exercise levels, smoking habits, and alcohol consumption. A diet high in saturated fats and sugars, for example, can contribute to obesity, type 2 diabetes, and cardiovascular disease. Lack of physical activity further exacerbates these risks. Smoking is a significant risk factor for various cancers, respiratory diseases, and heart conditions. Environmental factors encompass external influences like exposure to pollution, harmful chemicals, or even socioeconomic conditions that affect access to healthy food or safe environments for exercise.

For instance, the development of heart disease typically involves a genetic predisposition alongside lifestyle factors like a sedentary lifestyle, a diet high in processed foods, and smoking. Environmental stress could also play a role. Type 2 diabetes is another example, often linked to genetic susceptibility combined with obesity, poor diet, and insufficient physical activity. Cancer can be influenced by inherited genes, exposure to carcinogens in the environment (e.g., asbestos, UV radiation), and lifestyle choices like smoking and excessive alcohol intake. The interaction of these factors means that individuals with certain genetic risks can often mitigate their chances of developing NCDs through healthy lifestyle choices, while those without strong genetic risks can still develop NCDs if their lifestyle and environment are detrimental to their health. Understanding this multifactorial nature is crucial for prevention and effective management strategies.