Dismal economic data that pressured the entire market at the end of July rolled right off the backs of some high-flying healthcare stocks. These three more than doubled, all for very different reasons.

Here's what sent their share prices screaming higher.

Company (Ticker) Price Change in July 2020 Market Cap
Altimmune (ALT -12.55%) 148% $851 million
Owens & Minor (OMI -1.35%) 111% $1.0 billion
Arbutus Biopharma (ABUS -2.38%) 109% $263 million

Data source: Yahoo! Finance.

Three test tubes containing different-colored liquids

Image source: Getty Images.

1. Altimmune: Through the nose

This clinical-stage biotechnology company doesn't have any products to sell yet, but Altimmune's attempt to develop a single-dose intranasal coronavirus vaccine is getting lots of attention. The stock soared last month after a subsidiary of General Dynamics agreed to coordinate government funding efforts for the Maryland-headquartered biotech and its vaccine candidate, AdCOVID.

Altimmune will need all the funding it can find, because the company plans to begin manufacturing AdCOVID before the end of October. The company still hasn't filed an investigational new drug application with the Food and Drug Administration; that would need to be approved before the company could begin a human proof-of-concept trial with its coronavirus vaccine candidate.

Altimmune ended March with just $11 million in cash after losing $3.9 million during the first three months of 2020. Despite the lack of progress thus far with AdCOVID, last month, the company used a value-diluting share offering to add $132 million to its cash cushion.

2. Owens & Minor: Personal protective equipment

This company connects healthcare providers with manufacturers of healthcare products. The stock soared last month after the company reported preliminary results for the second quarter that were much better than expected, thanks to unprecedented demand for personal protective equipment.

The average analyst following Owens & Minor expected the company to lose around $0.03 per share, but COVID-19-related demand was stronger than anyone expected. Instead of a slight loss, the company anticipates adjusted second-quarter earnings of between $0.18 and $0.20 per share.

Sales of gloves, masks, and gowns were so good that Owens & Minor raised its full-year earnings expectations from a range of $0.50 to $0.60 per share to between $1.00 and $1.20 per share.

A gloved hand holding a beaker with cash in it

Image source: Getty Images.

3. Arbutus Biopharma: Patent ruling

This clinical-stage biotechnology company is developing an antiviral treatment for hepatitis B, but that isn't what pushed up its stock price last month. The stock more than doubled because the U.S. Patent Trial and Appeal Board rejected a challenge to three patents that Arbutus has owned for years, regarding messenger RNA (mRNA) delivery technology.

The challenger to Arbutus' patents is Moderna (MRNA -2.21%), a company entirely reliant on mRNA drug development. The highest-profile candidate in Moderna's pipeline is a potential coronavirus vaccine called mRNA-1273, and it recently began a phase 3 trial expected to enroll around 30,000 patients.

Moderna argues that its proprietary delivery technology has advanced far beyond anything that appears in Arbutus' patents. If an appeal board doesn't agree, Arbutus could end up receiving royalties from Moderna.

Stocks to buy?

It's probably best to steer clear of all these recent highfliers.

Arbutus could be years from producing sales from an approved drug, and Moderna plans to appeal. Even if Moderna loses on appeal, Arbutus won't receive a dime unless mRNA-1273 or one of the company's other new drug candidates succeeds. Though it's operated for 10 years, mRNA-1273 is the first drug Moderna has advanced into a late-stage clinical trial.

While there's a chance that Altimmune will pick up more funding from the U.S. government to run clinical trials with its experimental coronavirus vaccine, it's far behind the competition. Without any data from human studies, it's much too early to expect success from the AdCOVID program.

And though exploding demand for personal protective equipment will push Owens & Minor into profitability in 2020, investors should know the company lost $62 million last year. Once spiking demand settles down, its stock could tumble.