Background | biologicdrugs

Pre clinical Phase: In order for a drug to be available to the public, it must undergo many tests, experiments, and observations. The process of developing a drug start with t years of studying. The preclinical Phase is the phase in which researchers use information already acquired about the drug to try and come up with a treatment. The first step, a preclinical phase, is to find a promising agent, which involves taking advantage of the advances made in understanding a disease, pharmacology, computer science, and chemistry. (Medscape) To do so, researchers break down their information and try to understand what is causing it. (Ex: mutation) After finding a promising agent, the researchers test that new drug on animals, particular rodents.

Scientists often use rodents to test new drugs during the preclinical stages of a drug.

If the drug is found safe enough on rodents, it is then tested on a small group of ill volunteers. For approximately every 5,000 to 10,000 compounds that enter preclinical testing, only one is approved for marketing. (Medscape). All these tests can come to the Benefit of the drug when the application to manufacture it is sent to the FDA (Food and Drug Administration). This IND application (Investigational New drug) requires much data about the new discovery. It must include the animal test results, clinical testing, chemical data, manufacturing data, etc.

The testing undergone on rodents and volunteers can influence the drug's IND application.

Phase 1: This phase is where patients are allowed to volunteer and be tested on. Generally, 20-100 patients are tested and are closely monitored. The testing begins with low doses that are gradually increased. Only patients that show optimistic signs of improvement are allowed to move on to Phase 2.

Phase 2: In this phase the testing continues but on a larger sample size. This phase also tests for the appropriate doses, method of delivery, etc. Typically, phase 2 studies involve 100 to 300 patients who suffer from the condition the new drug is intended to treat. During phase 2 studies, researchers seek to determine the effective dose, the method of delivery (ex, oral or intravenous), and the dosing interval, as well as to reconfirm product safety. (Medscape) Patients in this stage are continuously assessed. They are monitored for oncoming side effects.

This video provides a brief description about the Phases of developing a drug.

Phase 3: The final phase is phase 3. This is where final testing occurs. Patients across multiple sites are tested on the drug to seek the effectiveness. Phase III trials usually involve 1,000 to 3,000 patients in clinics and hospitals. Patients are usually asked a list of possible side effects, often derived from what was observed in phase II studies. (Medicine net). Even with all the experiments already done, 10% of medications still fail in Phase 3. After this phase is complete, the IND application is complete and is sent to the FDA for a result. Often times the answer is straightforward, accepted or rejected, but every once in a while the FDA requests further information or clarification before the official approval. Once a drug is approved, it can be marketed and prescribed by doctors.

The FDA reply to the application with either approval, or rejection.

Phase 4: This phase includes the feedback given by the public. This phase is just to ensure no side effects are found after its availability as a prescription. The main challenge to finally finish this process is to have the patience to wait years of studying, experimenting, and awaiting results from FDA. This is not to mention that after all that hard work; your drug could be rejected at an early phase. It's also vey expensive to make the drug. A 1993 report by the Congressional Office of Technology Assessment estimated the cost of developing a new drug to be $359 million. Newer figures place the cost at more than $500 million (Medscape).

Testing in Phase 2 continues until an ideal dosage is found.