A new COVID-19 vaccine candidate is entering Phase 1 clinical human testing today, after the U.S. Food and Drug Administration (FDA) accepted an application from Inovio Pharmaceuticals under the regulator’s Investigational New Drug program. Inovio plans to inject its first volunteer test subject with the INO-4800 DNA vaccine candidate it has developed, following promising results from preclinical studies performed on animals that did indicate increased immune response.

The Inovio DNA vaccine candidate works by injecting a specifically engineered plasmid (a small, independent genetic structure) into a patient so that their cells can produce a desired, targeted antibody to fight off a specific infection. DNA vaccines, while available and approved for a variety of animal infections in veterinary medicine, have not yet been approved for human use.

That said, Inovio’s work isn’t starting from scratch: The company previously completed a Phase 1 study for a DNA vaccine candidate for Middle East Respiratory Syndrome (MERS), where it showed promising results and a high level of antibodies produced in subjects that persisted for an extended period of time.

Inovio has been able to scale up quickly, developing and producing “thousands of doses” of INO-4800 in just a few short weeks in order to support its Phase 1 and Phase 2 trials. The company has done so in part thanks to backing from the Bill and Melinda Gates Foundation, as well as funding from other nonprofits and organizations. If clinical trials are successful, Inovio says it will be able to have up to one million doses of the vaccine ready by the end of the year, for use both in additional trials and for potential emergency use pending authorization.

This is the second vaccine to undertake Phase 1 clinical testing on human subjects: Moderna began its trial in mid-March. Inovio’s trial will be made up of 40 volunteers, all healthy adults selected via screening conducted at either Philadelphia’s Perelman School of Medicine at the University of Pennsylvania, or the Center for Pharmaceutical Research in Kansas City. It’ll span the next several weeks, and the company expects data around the immune responses from test subjects, as well as info pertaining to the safety of the treatment for humans, to be available by late this summer.

Any broad clearance or approval for use is still likely at least a year to 18 months away, but the pace with which human trials are beginning is still exceptional, so hopefully we won’t have to wait too much longer than that.