We're less than two months into 2020, and a handful of biotech stocks have more than doubled their investors' money already. Shares of these drugmakers have gained attention for different reasons, but their shareholders and potential new investors all want to know if they can continue to impress for the rest of the year and beyond.

Let's look at three big biotech gainers in the early stages of 2020.

Company (Symbol) Year-to-Date Performance Market Cap
Anavex Life Sciences (AVXL -3.48%) 128% $346 million
BioXcel Therapeutics (BTAI 3.94%) 167% $521 million
AdaptImmune Therapeutics (ADAP -10.08%) 235% $703 million

Data source: Yahoo! Finance.

Anavex Life Sciences: No rush to finish

Earlier this year, shares of Anavex Life Sciences began climbing in response to a couple of developments regarding its lead candidate, 2-73, for the treatment of Alzheimer's disease and a handful of other neurological conditions. In January, the company finished enrolling 120 patients with Parkinson's-driven dementia into a phase 2 trial with 2-73.

Three scientists examine a test tube in a laboratory setting.

Image source: Getty Images.

In February, the 2-73 program took another step forward when the FDA granted the experimental treatment a fast-track designation for the treatment of Rett syndrome, a rare neurological disorder. This could speed up the review process once Anavex produces some phase 3 trial data.

Anavex shares could soar if 2-73 can show evidence of a benefit for patients with any of these neurological disorders, but a look at the company's track record says investors should watch this story develop from a safe distance. 

It's been almost four years since Anavex reported success from a mid-stage trial with 2-73 involving 32 early-stage Alzheimer's patients, but the company still hasn't completed enrollment of the subsequent phase 3 study needed to support a new drug application. In fact, the company's only halfway finished enrolling patients with mild to moderate Alzheimer's into a phase 3 trial meant for 450 patients. With roughly 44 million Alzheimer's patients worldwide, it hardly seems as if Anavex is in a hurry to produce any pivotal trial data for its lead candidate. 

2. BioXcel Therapeutics: Thanks for noticing, SunTrust

BioXcel has been soaring since an analyst from SunTrust cranked up her price target on the previously underappreciated biotech stock. In February, Robyn Karnauskas raised her price target on this stock to $150, which is 275% higher than its recent price. 

Seated outdoors, a healthcare provider speaks with a smiling older woman.

Image source: Getty Images.

BioXcel is developing a new delivery mechanism for dexmedetomidine, a powerful norepinephrine blocker that's been available for decades as an intravenously infused surgical sedative. Dexmedetomidine's also being used off-label to treat delirium, insomnia in intensive care units, and drug withdrawal symptoms.

BioXcel's lead candidate, BXCL501, is dexmedetomidine in the form of a sublingual film, and it's being rapidly developed for the acute treatment of agitation caused by schizophrenia, dementia, and opioid withdrawal.

It's been less than two years since BioXcel made its stock market debut, and the company's already started a pivotal phase 3 trial with BXCL501 involving agitated patients with schizophrenia. Bioxcel's also testing BXCL as a treatment for patients with dementia-driven agitation, and opioid withdrawal studies recently received a green light from the FDA.

The company expects to report phase 3 schizophrenic agitation data in the middle of 2020, and another strong showing could send the stock soaring much further. Given the well-understood profile of BXCL501's active ingredient, a slam dunk seems likely. 

3. Adaptimmune Therapeutics: Four responders

Using re-engineered T-cells to start a fight with cancer cells works wonderfully for blood-based malignancies, but patients with solid tumors haven't seen the same benefits. This is where Adaptimmune Therapeutics wants to make a difference, but since its public debut in 2015, Adaptimmune has struggled to show an appealing risk-to-benefit ratio for a handful of experimental T-cell therapies it's developing for the treatment of solid tumors.

A miniature shopping cart filled with a colorful array of pills sits atop a scattered pile of hundred dollar bills.

Image source: Getty Images.

Despite a relative lack of surface area that solid tumors leave exposed to Adaptimmune's re-engineered T-cells, the company reported partial responses from four patients treated with its experimental therapies. As a result, the stock rocketed past the clouds -- but investors probably shouldn't hold their breath for confirmations of the positive early signals.

The responses Adaptimmune reported weren't from the same study or even the same experimental therapy, and two of the four responses reported weren't officially confirmed. The company also neglected to mention the duration of the four observed responses, which probably means they weren't long enough yet to draw any meaningful conclusions about the benefit-to-risk ratio that Adaptimmune's candidates might provide.  

Four partial responses from patients with heavily pre-treated cancer is an encouraging step in the right direction, but investors want to watch this story develop further from a safe distance before risking a dime. 

The most likely climber

It's hard to predict what's in store for BioXcel and its sublingual sedative, but at least we know the main ingredient actually works as intended. That's a lot more than we can say for any new drug candidates from Anavex or Adaptimmune. If you feel compelled to bet on success for one of these drugmakers, BioXcel's the best option by a mile.