Luke O'Neill says an oral drug from Pfizer against coronavirus is "our big hope next year".
The company says final results from an analysis of 2,246 adults testing its Paxlovid drug show it "significantly reduced" the risk of hospitalisation or death by 89%.
It says this data has been shared with the US Food and Drug Administration (FDA) as part of an "ongoing rolling submission for Emergency Use Authorisation".
Albert Bourla, Pfizer's CEO, says: "This news provides further corroboration that our oral antiviral candidate, if authorised or approved, could have a meaningful impact on the lives of many.
"This underscores the treatment candidate's potential to save the lives of patients around the world.
"Emerging variants of concern, like Omicron, have exacerbated the need for accessible treatment options for those who contract the virus, and we are confident that, if authorised or approved, this potential treatment could be a critical tool to help quell the pandemic."
Prof O'Neill told Pat Kenny things are looking very positive.
"For me, this is our big hope next year when this drug becomes available - it will really repress the virus.
"As we saw from the first round of information, there was an 89% decrease risk of hospitalisation.
"That held up, and they've given us a bit more.
"If you take the tablets within three days of symptoms starting, it's an 89% decrease risk of hospitalisation.
"If you take them five days after it's 88%, which is pretty good.
"Even five days after symptoms there's a big protection against hospitalisation."
And he says this is even higher in older age groups.
"There's a 94% protection in the over-65s... and then there was a 10-fold decrease in viral load once you started taking them.
"So it really does kill the virus, which was superb to see.
"And then the last part, which is really important, it worked against Omicron.
"You can see now how we're so looking forward to that drug being made available".
'I could see an army of immune troops'
Prof O'Neill, who is recovering from COVID-19 infection himself, says his vaccine did its job.
"Back to normal Pat, much better - the vaccine did its job.
"In my mind I could see an army of immune troops protecting my lungs.
"But luckily it was very mild; the symptoms were just like a cold - a few sniffles, a little bit of coughing.
"But about two days ago actually I felt back to my old self".
He says an antigen test which he took came up as positive almost immediately.
"The antigen tests are really holding up, it's amazing how accurate they are.
"In my case... it came up immediately - that the band was in the window within three seconds.
"And it's a really good way to show if you're positive or not.
He adds: "I know there's a cost implication of course - and they should be free really, shouldn't they, in my view to make them more readily available".
On Christmas, he suggests people have to live their lives.
"People have to enjoy Christmas, haven't they? I think all this fear doesn't help anybody.
"The great phrase I saw is we have to learn how to wait and not to panic with Omicron.
"People should be able to mix, and again just follow the guidelines.
"You need to be sensible and restrict your socialising - but you should plan for something of an enjoyable Christmas".