Here’s what you need to know about clinical trials as drug makers push forward with coronavirus vaccine studies

Whether you’re new to investing in pharmaceutical or biotechnology companies or simply paying close attention to the race to develop a COVID-19 vaccine, questions may have occurred about how clinical trials work — here’s what you need to know to understand the process.

The first thing is that we’ve never seen vaccines developed as quickly as what is happening right now. It took a year and a half to develop a Zika vaccine, four years for a mumps vaccine, and 10 years for a flu vaccine.

The COVID-19 vaccines being developed by AstraZeneca AZN, 3.13% AZN, 2.77%  and the University of Oxford, BioNTech BNTX, 1.97%  and Pfizer Inc. PFE, 0.51%, and Moderna Inc. MRNA, 2.34%  are well into Phase 3 clinical trials in the U.S., with the makers of all three claiming it’s possible to have clinical data from the late-stage studies for their vaccine candidates during this calendar year.

It’s been nine months since Chinese authorities first notified world health officials about the presence of the virus.

What each clinical-trial phase means

Preclinical studies: These are studies that test how a drug or vaccine fares in animals, often macaques, a kind of monkey, or mice. These studies are traditionally performed before a therapy or vaccine moves into clinical trials with humans; however, in the pandemic, some preclinical trials for COVID-19 vaccines have been conducted concurrently with Phase 1 trials. “I don’t think proving this in an animal model is on the critical path to getting this to a clinical trial,” Dr. Tal Zaks, Moderna’s chief medical officer, told Stat News in March.

Phase 1 clinical trial: These are small studies designed to evaluate the safety and efficacy of a drug or vaccine in healthy adults. In the case of the COVID-19 vaccine candidates, this means fewer than 200 people were enrolled in the early-stage studies in the U.S., including ones conducted by BioNTech and Pfizer, Inovio Pharmaceuticals Inc. INO, 7.95%, and Moderna Inc. Inovio’s early-stage study enrolled 40 people.

These trials focus on safety; assess immunogenicity, which is the ability to generate an immune response; and help researchers better understand the correct dosing amount. (Based on the Phase 1 findings, for example, BioNTech and Pfizer plan to advance a two-dose regimen of 30 micrograms of their candidate, BNT162b2, into the Phase 2/3 trial.)

Phase 2 clinical trial: The midstage studies also assess dosing amounts and enroll hundreds of participants. In some cases, the trials overlap, such as Novavax Inc.’s NVAX, 3.60%  Phase 1/2 study for its experimental COVID-19 vaccine, which has enrolled 131 healthy adults between the ages of 18 and 59. (The first two phases of the study are being conducted in Australia, but the late-stage trial is expected to be conducted in the U.S.) “This phase includes studies that may provide additional information on common short-term side effects and how the size of the dose relates to immune response,” the Food and Drug Administration has stated in public documents.

It’s common for phases to overlap, said Dr. Henry Miller, a former FDA official. “Phase 1 merges almost imperceptibly into Phase 2 very often,” he said.

Phase 3 clinical trial: This is the crucial phase. The goal is to enroll thousands of people, to better evaluate how a vaccine candidate performs in a significantly larger patient population. AstraZeneca, BioNTech, Pfizer and Moderna have all committed to enrolling up to 30,000 participants in their late-stage trials. “Phase 3 is the final and most important phase where the vaccine candidate is tested in the field, if you will,” said Dr. Howard Koh, professor of public health leadership at the Harvard T.H. Chan School of Public Health and a former U.S. health official.

These trials focus on safety; assess immunogenicity, which is the ability to generate an immune response; and help researchers better understand the correct dosing amount. (Based on the Phase 1 findings, for example, BioNTech and Pfizer plan to advance a two-dose regimen of 30 micrograms of their candidate, BNT162b2, into the Phase 2/3 trial.)

Phase 2 clinical trial: The midstage studies also assess dosing amounts and enroll hundreds of participants. In some cases, the trials overlap, such as Novavax Inc.’s NVAX, 3.60%  Phase 1/2 study for its experimental COVID-19 vaccine, which has enrolled 131 healthy adults between the ages of 18 and 59. (The first two phases of the study are being conducted in Australia, but the late-stage trial is expected to be conducted in the U.S.) “This phase includes studies that may provide additional information on common short-term side effects and how the size of the dose relates to immune response,” the Food and Drug Administration has stated in public documents.

It’s common for phases to overlap, said Dr. Henry Miller, a former FDA official. “Phase 1 merges almost imperceptibly into Phase 2 very often,” he said.

Phase 3 clinical trial: This is the crucial phase. The goal is to enroll thousands of people, to better evaluate how a vaccine candidate performs in a significantly larger patient population. AstraZeneca, BioNTech, Pfizer and Moderna have all committed to enrolling up to 30,000 participants in their late-stage trials. “Phase 3 is the final and most important phase where the vaccine candidate is tested in the field, if you will,” said Dr. Howard Koh, professor of public health leadership at the Harvard T.H. Chan School of Public Health and a former U.S. health official.

This article was originally posted by MarketWatch.