The COVID-19 coronavirus. Presidential campaigns. Uncertainty about what the Federal Reserve Board will do with interest rates. All of these factors have weighed on investors' minds as the stock market pulled back this week.

But some stocks zoomed higher instead of pulling back. Three biotech stocks that absolutely soared this week were Arcus Biosciences (NYSE:RCUS), Avadel Pharmaceuticals (NASDAQ:AVDL), and Abeona Therapeutics (NASDAQ:ABEO). Here's what fueled huge gains for these stocks -- and whether or not they're smart picks to buy now.

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1. Arcus Biosciences

Shares of Arcus Biosciences skyrocketed 51% higher this week. Most of this huge jump came after Mizuho Securities' analyst Mara Goldstein reiterated a buy rating on Arcus with a one-year price target of $22, twice as high as the biotech stock's closing price in the previous week.

Arcus boasts a robust pipeline for a clinical-stage biotech. Its lead candidate is AB928, which is being evaluated in several early- and mid-stage clinical studies for treating multiple types of cancer.

The biotech expects to announce results from some of those clinical studies featuring AB928 beginning in mid-2020. It also plans to start a phase 1b/2 study early this year combining the experimental drug with current standards of care in treating prostate cancer. In addition, Arcus anticipates reporting results from studies evaluating other pipeline candidates, including AB122 and AB154, later in 2020.

2. Avadel Pharmaceuticals

Shares of Avadel Pharmaceuticals soared nearly 32% this week. The drugmaker's big news came on Friday with the announcement that it had entered into a definitive agreement to sell new shares in a private placement with a group of institutional investors.

Stock offerings often cause biotech stocks to fall. In Avadel's case, though, investors appeared to be excited that the company was raising gross proceeds of close to $65 million to fund its development of experimental sleep disorder drug FT128.

Avadel completed enrollment in December for a late-stage study evaluating FT128 in treating excessive daytime sleepiness and cataplexy in patients with narcolepsy. The company expects to announce results from this study in the second quarter of 2020.

3. Abeona Therapeutics

Abeona Therapeutics stock jumped 30% higher this week. The company didn't have any news over the last five days, though. Its big gain this week appears to stem from continued momentum from a clinical trial update on Feb. 12.

That update actually didn't even come from Abeona. Researchers from the Abigail Wexner Research Institute (AWRI) presented interim data from a couple of clinical studies featuring Abeona's drugs at the WORLD Symposium. This data indicated promising potential for ABO-102 in treating mucopolysaccharidosis type IIIA (MPS IIIA) and ABO-101 in treating MPS IIIB.

AWRI initially developed the gene therapies for treating these two rare diseases. Abeona licensed the underlying technology from AWRI. The biotech's lead pipeline candidate, though, is EB-101, which the company recently advanced to a phase 3 clinical study for treating rare genetic disease recessive dystrophic epidermolysis bullosa (RDEB).

Are they buys?

Most investors are better off steering clear of clinical-stage biotech stocks. That rules out Arcus Biosciences and Abeona Therapeutics. 

Avadel, on the other hand, already markets four sterile injectable products, with its latest Food and Drug Administration approval coming in December 2019. However, the company's primary focus right now is on FT128. The experimental narcolepsy drug could have a significant opportunity if approved, especially with the appeal of its once-nightly dosing formulation.

I wouldn't go so far as to call Avadel a stock to buy right now. But it's definitely one for investors to keep on their radar.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.