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What Happens During Each Phase Of A Clinical Trial?

Posted on April 6, 2023 by Elizabeth Swanson

Clinical trials are voluntary research studies that bring safe, effective medical treatments to the public. Those who participate in clinical trials have the opportunity to try new treatments up to a decade before they’re widely available and approved by the Food and Drug Administration (FDA). This may be life lengthening and occasionally lifesaving. 

“Participating in a clinical trial can be an important part of cancer care. It increases someone’s treatment options,” says Amy M. Weise, D.O., a medical oncologist at Henry Ford Health. “Cancer clinical trials often include standard-of-care drugs in combination with experimental drugs. The goal is to improve upon drugs that are already available or create new combinations of drugs that might be even more effective.” 

Phases Of Clinical Trials

To ensure safety and efficacy, clinical trials undergo several phases before the FDA approves them for widespread public use. Each phase has a different goal, and your diagnosis and state of health determine which phase you qualify to participate in. Here’s what happens during each phase of a clinical trial. 

Phase 0

Phase 0 clinical trials are pre-human studies. Researchers will determine whether the drug hits the target (or tumor) that it’s meant to hit. “They’ll also do safety data collection and ensure the drug isn’t negatively affecting blood cell count or organ function,” says Dr. Weise.    

Phase 1 

This is the first phase that involves humans. It determines the safety of the drug and plays a large role in deciding whether the drug will move forward into development. 

“Almost everyone who has cancer is a candidate for phase 1, but you have to have a life expectancy of at least three months,” says Dr. Weise. “You also have to have adequate kidney and liver function. And if you’ve had a major medical illness, such as a recent heart attack or stroke, you won’t qualify.”

Depending upon the treatment being investigated, there’s always a possibility that phase 1 clinical trials will offer benefits to the patient. “That said, the primary point of phase 1 is safety, so phase 1 studies start with low doses, which are gradually increased,” says Dr. Weise. “We call higher doses MTD, or the maximum tolerated dose. Once you reach that level, the trial is expanded to include more patients to gather more safety and efficacy data. The drug then moves into phase 2.”

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Phase 2

Many studies are now designed to combine both phase 1 and phase 2, which includes an escalation phase to find the recommended dose, followed by an expansion phase. 

Once the recommended dose is identified, about 20 to 30 participants are added to determine the effectiveness of the treatment. During phase 1, people with all types of tumors are included, but in phase 2, participants are narrowed down to those with one type of tumor. All participants are also getting the same dose level, which is the level that is supposed to be a biologically effective dose. 

Phase 2 studies that do not include a phase 1 portion often involve a larger patient population and they are disease specific. The primary goal of phase 2 studies is to determine if the drug works in a specific patient population. If it does, it then moves on to phase 3.

Phase 3

A traditional phase 3 trial is known as a randomized control trial, where patients receive either one of two treatments. (For example, treatment A or treatment B.) “Treatment A might be the experimental treatment and treatment B might be the current standard-of-care drug,” says Dr. Weise. “You compare the treatments to see if the experimental drug outperforms the standard-of-care drug. If it does, it may become the new standard-of-care drug.” 

Phase 3 trials are typically the largest studies—many include thousands of patients—and FDA approval comes after phase 3. 

“Having phase 1, phase 2 and phase 3 trials available for patients really broadens their opportunities and treatment options,” says Dr. Weise. “If you’re interested in participating in a clinical trial, talk to your oncologist. You can also visit a website called clinicaltrials.gov. It allows you to search clinical trials based upon tumor type. Each trial also includes inclusion and exclusion criteria, which tells you whether you qualify for a particular trial.

“I think it’s important for patients to know what clinical trials are and how they can fit into their cancer care. I’m passionate about clinical trials. Clinical trials represent our greatest hope for moving cancer treatment forward.” 

Amy M. Weise, D.O., is a medical oncologist at Henry Ford Health. She sees patients at Henry Ford – Cancer in Detroit and Henry Ford Medical Center – Columbus.

Categories : FeelWell

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