The stock market bounced back on Monday from its losses late last week, as the initial news of President Donald Trump testing positive for COVID-19 gave way to positive comments about his ongoing recovery. It's not uncommon for stocks to fall going into a weekend during which there's considerable uncertainty, only to see a rebound once facts are known and worst-case scenarios haven't played out. Just after 11 a.m. EDT, the Dow Jones Industrial Average (^DJI 0.06%) was up 381 points to 28,064. The S&P 500 (^GSPC -0.22%) gained 46 points to 3,395, and the Nasdaq Composite (^IXIC -0.52%) picked up 176 points to 11,251.

With the White House going through a coronavirus crisis, it's not surprising to see coronavirus-fighting stocks in the spotlight. In particular, Regeneron Pharmaceuticals (REGN -0.80%) and Gilead Sciences (GILD -1.15%) saw their stocks climb on Monday following news that their treatments had been used in the president's care. Elsewhere in healthcare, a big deal boosted shares of MyoKardia (MYOK).

Hand wearing blue glove holding dropper putting liquid into test tubes, with box labeled COVID-19 nearby.

Image source: Getty Images.

Looking for a proven COVID-19 treatment

Shares of coronavirus stocks Regeneron and Gilead were up 6% and 3% respectively. Investors in the two companies seemed pleased that the doctors treating the president had chosen their candidate treatments rather than those of rivals.

Regeneron has been working on a combination of two antibodies that together are intended to help the body's immune system attack COVID-19. Initial results from a study of the antibody cocktail had been encouraging, showing reduced viral loads, alleviated symptoms, and few side effects.

In addition, Gilead's remdesivir has been used in the president's care. The wide-spectrum anti-viral treatment is authorized for emergency treatment of patients who have been hospitalized due to COVID-19. Although remdesivir didn't show significantly increased survival rates among patients in a study, it did reduce the amount of time it took for coronavirus patients to recover from the disease.

Obviously, Gilead and Regeneron could hardly ask for a higher-profile patient to try out their proposed treatments. Whether that plays any role in the approval process for the two companies remains to be seen, but if the eventual results of the course of treatment are positive, then it should be a boost to the two companies' prospects.

Bristol-Myers hearts MyoKardia

Shares of MyoKardia soared 58% on Monday morning. The heart therapy specialist got a buyout bid valuing the company at $13 billion.

Bristol-Myers Squibb (BMY 0.96%) will pay $225 per share in cash for MyoKardia. The deal is expected to close by the end of the year.

Bristol-Myers cited the value of adding the cardiovascular disease treatment mavacamten to its portfolio of heart medicines. Mavacamten treats a chronic disease called obstructive hypertrophic cardiomyopathy, and the two companies expect to file a new drug application to the U.S. Food and Drug Administration in the first quarter of 2021.

Bristol-Myers is optimistic that mavacamten can fight other types of heart disease. It also played up the value of other pipeline candidates that MyoKardia has worked on, including a couple of clinical-stage therapeutic treatments, danicamtiv and MYK-224.

Some investors believe Bristol is paying too high a price for MyoKardia. Yet with pharmaceutical companies looking for growth prospects anywhere they can find them, paying up for the heart disease specialist is consistent with what investors have seen from healthcare stocks repeatedly in the recent past.