Shares of CRISPR Therapeutics (NASDAQ:CRSP) have gained 52% in 2019, but the stock is still 40% below the record high price it reached in 2018. If you've been holding onto shares of the gene-editing pioneer since their heyday last May, now is not the time to let go.

While reporting third-quarter earnings, management highlighted a few catalysts that could send the biotech stock through the roof. Here are three big ones to look out for.

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1. Incoming results for CTX001

This February, in partnership with Vertex Pharmaceuticals (NASDAQ:VRTX), CRISPR Therapeutics treated a patient for the first time with CTX001. This drug is essentially a bag of a patient's own stem cells that CRISPR has edited outside of the body to produce fetal hemoglobin.

Vertex and CRISPR are actually testing CTX001 in a pair of trials, one for patients with transfusion-dependent thalassemia (TDT) and another for patients with severe sickle cell disease (SCD). Both diseases are caused by faulty hemoglobin genes, and patients rely on frequent blood transfusions that are painful, inconvenient, and expensive, and which eventually lead to irreparable organ damage.

If the CRISPR-edited stem cells work as expected, they'll find a home in patients' bone marrow and produce red blood cells with enough fetal hemoglobin to do their job. To be considered successful, six months following treatment, TDT patients should be able to reduce or completely halt their need for frequent blood transfusions.

People born with SCD often experience painful, life-threatening blood vessel blockage caused by red blood cells that have folded into a sickle shape. Following a single infusion of CTX001, the red blood cells of patients with severe SCD should be able to retain their proper shape and in turn dramatically reduce the observed rate of vaso-occlusive crises. 

CRISPR Therapeutics will present initial CTX001 results before the end of the year, most likely at the American Society of Hematology's (ASH) annual meeting in December. If those results appear competitive with those we've seen from bluebird bio (NASDAQ:BLUE) and its LentiGlobin program, CRISPR Therapeutics could become one of the year's top-performing biotech stocks.

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2. A new way to treat cancer

CRISPR Therapeutics has already started treating cancer patients with an off-the-shelf solution made from donor cells called CTX110. This is a big deal because engineering a patient's own immune system cells to recognize proteins commonly found on cancer cells takes a lot of time that these patients don't have.

Yescarta from Gilead Sciences (NASDAQ:GILD) and CTX110 are both made of immune cells that target CD19, a protein often found on the surface of cancer cells. Sales of Yescarta, an autologous cellular therapy, have been fairly disappointing, but an allogenic solution that can be ready for infusion almost immediately is far more likely to generate blockbuster sales.

Positive results from the ongoing study with CTX110 could give CRISPR shares more lift than CTX001 for a couple of reasons. Unlike CTX001, CRISPR Therapeutics still owns its cancer programs outright and won't have to share any profits they generate with Vertex or anyone else. Also, the company intends to begin clinical trials with a BCMA targeting candidate called CTX120 in the first half of 2020, plus a third allogeneic cell therapy that targets CD70 isn't far behind.

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3. A new way to treat diabetes

Type 1 diabetes isn't nearly as common as type 2, but it still affects more than 20 million people worldwide. Type 1 patients require insulin throughout their lives because their immune system has destroyed cells in the pancreas that naturally produce the crucial hormone.

It is possible to transplant insulin-producing cells from a healthy person into the pancreas of someone with diabetes, but the procedure's rarely performed because patients need to suppress their immune systems to protect the transplanted cells.

In partnership with privately held ViaCyte, CRISPR is developing a line of off-the-shelf stem cells that produce insulin, and PD-L1, but lack a gene responsible for inciting an immune system attack.

You may recognize PD-L1 as the surface protein that cancer cells exploit to shut down an immune system attack. In a petri dish, these engineered stem cells appear to protect themselves. If they can do the same once transplanted into a live pancreas, CRISPR will have a functional cure for type 1 diabetes.

What could go wrong

Proving something works as expected in a lab is only the first step toward providing evidence it will do the same for real people. It's important to remember that every drug that reaches the human testing stage proved itself outside of a live organism, but the vast majority can't replicate the success where it matters most.

Investors also need to brace themselves for early disappointment from CVX001 and CVX110 because finding the right number of cells to infuse for experimental treatments is a process of trial and error. Moreover, researchers tend to err on the side of caution and it could take several attempts before we know if the company has a winner on its hands.

Although there are plenty of potential problems that could cause CRISPR Therapeutics stock to tank, any one of these incoming catalysts is significant enough to produce market-thrashing gains. If you're an adventurous investor with a diverse portfolio, it's worth the risk.