From the lab to the pharmacy: Let's look at the drug development process

November 15, 2015

Previous issues of Follow the Script™ have touched on the drug approval process in Canada, but let’s take a step back and take a look at the research and development that’s involved before a drug is approved by Health Canada to enter the market. Pharmaceutical research is a large and growing business internationally, and drug manufacturers must follow a lengthy and complex process to study and test new drugs. Most drugs that start the development process drop off at various stages and never make it to the market.

Drug discovery

A new drug starts out with scientists developing a substance – either chemical or biological – that could be used to treat a specific disease or condition. Sounds simple, but scientists look at thousands of compounds before finding one that looks promising. This substance is tested in tissue cultures and a variety of small animals to determine its effects. If the substance, or drug, is doing what the scientists expect and want it to, additional studies are undertaken. This stage is called pre-clinical development and includes additional animal testing as the drug is given in different amounts over different periods of time to determine its effects – expected and unexpected – and the dosage responsible. If the drug isn’t causing any serious harm and is producing the desired effect, it can proceed to the next stage: clinical trials.1

Clinical trials

The purpose of clinical trials is to study the dosage, effectiveness, and safety of the drug in humans with the participants and the results closely monitored. Clinical trials are conducted by physicians along with a research team. All clinical trials are done in phases under controlled conditions with each phase designed to study a specific aspect of the drug.

Phase one:

In this phase, researchers are trying to find out whether the drug is safe and whether people can tolerate it. This can be the phase with the highest level of risk as the drug has never been administered to humans before. A small number of healthy participants is divided into groups taking different dosages of the drug at different times. The researchers are determining a safe dose of the drug to bring about the desired result, as well, they are collecting information on the side-effects the participants experience.

Phase two: 

In phase two the effectiveness of the drug for a particular disease or condition is studied based on the dosage and schedule determined in phase one. This phase usually involves a larger group of people who have the condition but are otherwise healthy. The researchers are continuing to gather information on the effects of the drug at different dosages and to identify common side-effects.

Phase three:

Phase three trials generally involve a much larger number of participants than the other phases, sometimes at many different locations. Sometimes the drug is assessed against other drugs or treatments currently in use. If this phase shows that the new drug is safe and effective, and its value outweighs any risks, a new drug submission can be made to Health Canada for approval to market the drug.

Phase four:

Sometimes a drug goes on to a phase four clinical trial after it’s approved and on the market. In this phase researchers are gathering additional information on possible risks and benefits of the drug over the long term.2

The role of Health Canada

To protect the public, all prescription and non-prescription drugs for sale in Canada have to be approved by Health Canada before they can go on the market. Health Canada’s role is to regulate, evaluate, and monitor the safety, efficacy, and quality of drugs (and other products). This includes both biologic and chemical-based drugs.4

For new drugs in development, Health Canada reviews:

  • Applications to conduct clinical trials. The applications include details about the research and pre-clinical studies, the dosage of the drug, and information about the researchers conducting the trial. Permission to conduct a clinical trial is granted once Health Canada is satisfied the drug is being used appropriately, any risks are minimized, and the objectives of the trial are likely to be met. Health Canada maintains a clinical trials database which provides an overview of many clinical trials taking place in Canada.5
  • New drug submissions from pharmaceutical manufacturers. These submissions include the results of the pre-clinical studies and clinical trials as well as other details about the drug’s packaging, labelling, side-effects and therapeutic claims. Even after approval is granted, Health Canada continues to monitor the drug. Manufacturers are required to provide updated information on adverse effects (i.e., side-effects), safety concerns, etc., that arise as the drug becomes more widely used.6

After the drug is approved…

Getting the new drug approved by Health Canada isn’t the last step. After receiving the approval, the pharmaceutical manufacturer conducts an educational and marketing campaign to doctors so they’ll prescribe the new drug. For example, if this drug treats a condition that has other options available, the manufacturer has to persuade doctors that this new treatment is better than existing treatments. As well, the pharmaceutical manufacturer promotes the drug to plan providers, like GSC and provincial drug plans, who will evaluate the drug for inclusion on their formularies for reimbursement.

Want to read more?

There’s also the continued reporting to Health Canada about adverse effects and what that can mean for a drug, even when it’s been on the market for a while. Read pages 4-6 of our Winter 2015 edition of Follow the Script, where we discuss Health Canada’s drug approval process in “Behind the Counter.”