Investors have been impressed at the rapid pace at which the stock market has clawed back its losses from early in 2022. The Nasdaq Composite (^IXIC -0.64%) in particular has rebounded sharply, and so it made sense for the index to take a brief break from its ascent early Wednesday. As of 7:45 a.m. ET, Nasdaq futures were down about a third of a percent.

Yet there's still plenty of excitement among individual Nasdaq stocks. Today, investors focused on the biotech stock arena, where a pair of companies saw their share prices rise sharply. Read on to learn why Adagio Therapeutics (IVVD -2.82%) and Vir Biotechnology (VIR -5.10%) made their way onto market participants' radar screens early Wednesday.

Medical professionals treating a patient with a respirator.

Image source: Getty Images.

Adagio announces a COVID-19 breakthrough

Shares of Adagio Therapeutics soared more than 67% in premarket trading Wednesday morning. The clinical-stage biopharmaceutical company announced success in trials studying its candidate drug adintrevimab as a prophylactic against or treatment for COVID-19.

Adagio's phase 2/3 trials met key primary endpoints, with the company claiming status as having found the first monoclonal antibody to reach statistical significance in providing protection to patients prior to being exposed to the virus causing COVID-19, after exposure but before infection, and after infection. Risks of becoming symptomatic with COVID for trial participants taking adintrevimab were down 71% compared to a placebo in patients who hadn't been exposed to the virus, while risks fell 75% among those who had been exposed.

Among patients already suffering from mild to moderate COVID-19, adintrevimab also showed promising results. Risks of hospitalization or death fell 66% compared to placebo generally, and those risks fell by an even steeper 77% for those who received the treatment within three days of first showing symptoms.

Adagio now plans to submit an Emergency Use Authorization application with the U.S. Food and Drug Administration in the second quarter of 2022 to use its drug for both preventing COVID-19 and treating patients who've already contracted it. At the same time, the company will keep working to keep its research updated for new variants as they emerge. Investors are hopeful that adding treatment options to supplement other companies' COVID-19 vaccines could boost Adagio's fortunes in the years to come.

Vir bounces on index invite

Elsewhere in biotech, shares of Vir Biotechnology were up more than 11% Wednesday morning. The company didn't have big news to announce about its treatment pipeline, but it did get some recognition from a key stock index manager that will increase awareness of the biotech stock among investors.

Vir Biotechnology will join the S&P SmallCap 600 index as of Monday, April 4. The move comes as the result of merger and acquisition activity in the banking sector, as regional banking leader M&T Bank is set to complete its acquisition of People's United Financial on or around that date. Both People's United and M&T are in the S&P 500, so the merger creates an opening that S&P Dow Indices decided to fill by making a series of promotions from its mid-cap and small-cap index ranks.

Interestingly, Vir's promotion doesn't come at the best possible time for the stock. Vir's share price has fallen by more than half just since December, as investors have seemed to conclude that COVID-19 treatments like the one Vir and profit-sharing partner GlaxoSmithKline have worked to promote will become less important over time.

In the long run, it's impossible to know how much permanent demand there could be for COVID-19 treatments. Nevertheless, as a proof of concept, both Vir and Adagio have opportunities to take their successes here and use them for advances in other diseases. That's a key element of the bullish argument for both stocks.