MONTGOMERY COUNTY, Pa. (CBS) — On Tuesday, Plymouth Meeting-based company Inovio Pharmaceuticals announced positive results from early-stage testing of its COVID-19 vaccine. But officials with the biotechnology company did not disclose complete data.

This sent shares of the company’s stock tumbling on Wall Street.

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Inovio’s CEO explains the vaccine testing results.

Six weeks ago, 36 people received two injections of the COVID-19 vaccine.

“Early phase 1 clinical trials on the COVID-19 vaccine that Inovio is developing demonstrated a very strong safety and very early but very promising immune responses from the trial,” Dr. J. Joseph Kim said.

Inovio says 94% of the trial participants demonstrated overall immune responses.

The company says it hopes to get data supporting the effectiveness of its COVID-19 vaccine early next year.