What happened

Shares of the developmental biotech Heat Biologics (HTBX 0.96%) jumped by as much as 21% in pre-market trading Wednesday morning. The company's shares perked up in response to the release of a pre-print (a preliminary article that has yet to be peer-reviewed) discussing the animal data for its COVID-19 vaccine candidate. The pre-print is currently available on bioRxiv's website. 

Heat's COVID-19 vaccine candidate uses a cellular heat shock chaperone protein, glycoprotein 96 (gp96), to deliver the SARS-CoV-2 spike protein to the immune system. This novel vaccine reportedly triggered strong cell-mediated immune responses in the respiratory tissue of transgenic mice.

A doctor holding out a vial labeled as COVID-19 vaccine.

Image source: Getty Images.

So what

Although Heat won't have a vaccine ready for public consumption anytime soon, its vaccine candidate may end up playing a critical role in halting the ongoing pandemic. The key issue is that Heat's vaccine is designed to ramp up T-cell immunity -- not simply antibodies.

That's a big deal because recent studies have clearly shown that antibodies often do not confer long-term immunity to this particular virus. Heat, in short, may have a hidden gem on its hands with this T-cell targeting vaccine candidate.    

Now what

The bad news is that Heat doesn't expect to launch a phase 1 trial for this vaccine until early next year. By then, there could be multiple COVID-19 vaccines -- and therapies -- already on the market.

That doesn't mean that Heat's promising COVID-19 vaccine candidate won't find an audience if approved late next year or in 2022. But it certainly won't be part of the first wave of commercial-stage COVID-19 vaccines. Biotech investors, in turn, should probably keep this potentially lengthy timeline in mind before buying shares.