Lack of clear information in first human data raises questions!
The first major readout of data from Inovio’s coronavirus vaccine programme seems to have fallen well short of investor expectations, sending the company’s shares into a slump.
Inovio says the DNA-based vaccine candidate INO-4800 stimulated an “immunological response” in 34 of 36 (94%) patients enrolled in its phase 1 trial, but didn’t define the nature of that response.
In particular, it did not disclose what proportion of the volunteers in the trial produced neutralising antibodies to SARS-CoV-2, the virus that causes COVID-19, saying its 94% response rate referred to “humoral (binding and neutralising) and T cell immune responses” without providing any details on their magnitude and duration.
The biotech has previously shown that INO-4800 generated neutralising antibodies and T cell responses against SARS-CoV-2 in preclinical studies, but the lack of clear information in the first human data seems to have given shareholders the jitters as its stock closed down 15% yesterday.
Stifel analyst Stephen Wiley said the company’s first statement on the results “is likely to raise more questions on the competitive immunogenicity front”.
The vaccine was found to be “generally safe” and well-tolerated, according to Inovio, which also revealed that it would advance into a larger phase 2/3 trial later this month or in August.
Inovio has repeatedly said that its DNA vaccines generate “balanced antibody and T cell immune responses” that will be important in the development of COVID-19 vaccines that are effective in both mild and serious infections.
In its press release, the company said that studies suggest around a third of patients who recover from COVID019 have low levels of neutralising antibodies in their blood.
That goes against conventional thinking in vaccine development, and could explain the fall-off in its share price, although may also reflect new FDA guidance that has been interpreted as raising the bar for efficacy in coronavirus vaccine studies.
It says that the “primary efficacy endpoint point estimate for a placebo-controlled efficacy trial should be at least 50%”, which some analysts think may be challenging to meet for the first generation of COVID-19 vaccine candidates.
Inovio chief executive Dr Joseph Kim also pointed out that INO-4800 “is the only nucleic-acid based vaccine that is stable at room temperature for more than a year and does not require to be frozen in transport or for years of storage, which are important factors when implementing mass immunisations to battle the current pandemic”.
The company also said that INO-4800 has been selected to participate in a non-human primate challenge study as part of the US government’s Operation Warp Speed, which is aiming to make a vaccine available by the end of the year.
