Are you looking for high-flying stocks that still have some fuel in the tank? If so, you'll be happy to hear about three biotechs that have already been experiencing great runs over the past year, and that could rise a whole lot further.

All of these companies are working on new drugs that could be worth billions, and successes with them would push their stock prices through the roof. But it's still a little too early to be certain that those treatments will reach the market.

Company (Symbol) 12-Month Gain Market Cap
Affimed (AFMD -4.52%) 143% $786 million
BioCryst (BCRX -2.10%) 325% $2.9 billion
Rigel Pharmaceuticals (RIGL -4.17%) 69% $715 million

Data source: Yahoo! Finance.

Affimed

This company is working on new cancer therapies that bring a component of the immune system called natural killer cells (NKs) into close contact with cancer cells. The company's lead candidate, AFM13, is a bispecific antibody -- in other words, it has two elements that bind to different targets. One segment of AFM13 attracts NKs while the other end binds to CD30 proteins, which are found on the surface of tumor cells.

Scientists working in a laboratory.

Image source: Getty Images.

Relapsed and refractory cancer patients in Affimed's REDIRECT study have responded to AFM13 as a monotherapy, but not at a rate Affimed has been willing to explain in detail. However, a different clinical trial sponsored by M.D. Anderson Cancer Center that starts PTCT patients out with an infusion of NKs that are already bound to AFM13 produced dramatic results. Treatment with NKs plus AFM13 shrank tumors for two of the first four evaluable patients, and the other two achieved complete remission.

Exciting response-rate data that appears when just a few patients begin testing a new cancer treatment tends to taper off as more patients enroll in the trial. After reporting an initial response rate of 100%, AFM13 has nowhere to go but down. If it doesn't sink very far, though, Affimed could have a blockbuster cancer treatment ready for a commercial launch in a couple of years.

BioCryst Pharmaceuticals

This company is developing easy-to-swallow drugs that act on proteins that are responsible for the symptoms of severe genetic disorders. BioCryst's first drug to earn approval, Orladeyo, is a once-daily capsule that decreases the activity of an enzyme that's overactive among patients with hereditary angioedema (HAE) and related disorders.

During a pivotal study, painful HAE attacks dropped by 70% or more for 50% of patients who received Orladeyo compared to just 15% of those given a placebo. First-quarter sales that reached $10.9 million were stronger than expected for a new treatment with existing competition. 

If sales of BioCryst's first drug continue upward at their present trajectory, the stock will keep climbing too. Success in an upcoming pivotal trial with another candidate, BCX9930, though, could send the stock through the roof. This experimental treatment for paroxysmal nocturnal hemoglobinuria (PNH) already produced significant hemoglobin level improvements in a proof-of-concept trial, so confirmation of its efficacy seems likely.

Scientists at work together in a laboratory.

Image source: Getty Images.

Rigel Pharmaceuticals

This is another biotech with one drug in commercial stages and another potential blockbuster in early clinical-stage trials. The FDA approved Tavalisse in 2018 to treat patients with chronic immune thrombocytopenia; sales so far haven't been thrilling, but they are growing.

Tavalisse sales reached just $12.4 million in the first quarter, but the company reported a $21.2 million profit. Rigel has been adding to its cash cushion thanks to an important collaboration deal with Eli Lilly (LLY -0.12%). In February, the big pharmaceutical company agreed to give Rigel $125 million up front for rights to a potential new Alzheimer's disease program.

Right now, Eli Lilly and Rigel Pharmaceuticals are co-developing R552 as a treatment for autoimmune and inflammatory diseases outside of the brain. Soon, Lilly will take the lead on the development of a candidate similar to R552 that can cross the blood-brain barrier. 

Rigel Pharmaceuticals sports a $715 million market cap, which is modest for a company with a commercial-stage drug that's already producing a steadily growing revenue stream. The company also has a shot at earning up to $835 million in milestone payments from Eli Lilly for R552 and subsequent programs. If a phase 2 study set to begin this year reads out positively, this stock will explode higher.