CRISPR Therapeutics (CRSP -3.62%) made news recently after unveiling some impressive results for its signature gene-editing drug, CTX001. Coupled with an earlier analyst upgrade from Oppenheimer, the news caused shares of CRISPR to surge by more than 25% on Nov. 19. Since then, however, CRISPR's stock has given back most of those gains.

Is this recent dip a good buying opportunity for investors? Let's go over some of the details surrounding CRISPR Therapeutics' recent results, how it compares to its competitors, and whether now's a good time to add this company to your portfolio.

Abstract image of a strand of DNA getting a piece removed via a pair of tweezers.

Image source: Getty Images.

A brief look at the results

CRISPR's first clinical update for its signature drug candidate, CTX001, was considered a definite success. The announcement included results from the first two patients who were treated with the gene-editing drug, with one patient having sickle cell disease and the other diagnosed with infusion-dependent beta thalassemia. Both patients reported that after being enrolled in the study for a length of time, key symptoms disappeared entirely.

For the patient with sickle cell disease, the main symptom being evaluated was the number of blockages that occurred due to the sickle-shaped nature of the blood cells. Whereas previously the patient had on average seven of these blockages (also known as vaso-occlusive crises) per year, during the nine-month treatment period, the patient had a complete absence of any blockages whatsoever.

A similar result was found in the patient with beta thalassemia, who required on average 16.5 blood transfusions each year historically. After two years of taking CTX001, however, this figure dropped down to zero, with the patient requiring no blood transfusions at all. While there are plenty more details that could be discussed, the key takeaway is that the early results have been excellent.

Potential competitors

While CTX001 has shown promising results thus far, it's not that far ahead of other competitor drugs being developed. Blood disorders, in particular, are a popular condition for gene-editing companies to tackle, with Editas Medicine (EDIT -4.03%) and Sangamo Therapeutics (SGMO -5.13%) both developing their own sickle cell disease and beta thalassemia treatments.

Editas' own sickle cell drug, EDIT-301, showed some promising preclinical results earlier this year at the European Hematology Association and is expected to provide a further update by the end of the year. However, unlike CRISPR, Editas' flagship drug doesn't target blood disorders but instead tackles a rare form of blindness in children, Leber congenital amaurosis. EDIT-101 targets babies with protein deficiencies in their retinas, preventing what would become an inevitable case of blindness.

As for Sangamo, the company has a fairly broad pipeline, with separate drugs for beta thalassemia and sickle cell disease, ST-400 and BIVV-003, in development. However, both of these drugs are still at a very early stage of clinical testing; one study enrolled two patients to be treated with ST-400 for beta-thalassemia. Early data is expected to come in before the end of the year, something that biotech investors should keep an eye out for.

Similarly to Editas, however, Sangamo's beta thalassemia and sickle cell treatments aren't its main drug candidates. Instead, the company's flagship treatment is SB-525, which targets patients with hemophilia A, a rare bleeding disease that's caused by a lack of blood plasma required to produce a crucial protein known as clotting factor VIII.

Is CRISPR the best gene-editing stock right now?

Whether CRISPR is the absolute best gene-editing stock at the moment is questionable. CRISPR does seem to be a front-runner in the sickle cell and beta thalassemia markets at the moment, which are estimated to become worth $3.5 billion and $5.5 billion, respectively, in the next few years. However, other gene-editing companies have an edge in treating other conditions where CRISPR doesn't have an edge. Sangamo's hemophilia treatment is a perfect example: This is an area that is expected to turn into a $14.8 billion market by 2025.

At the same time, some pharmaceutical companies that are venturing into the gene-editing world are moving away from using the popular CRISPR/Cas9 gene-editing tool developed by CRISPR Therapeutics. Novo Nordisk announced recently that instead of using CRISPR/Cas9 technology, it would opt for another mRNA-based technology developed by bluebird bio referred to as megaTALs. There's some research that indicates that this newer mechanism of gene editing is more precise than the older CRISPR/Cas9 system.

Although it's hard to say which gene-editing stock is the single best investment to choose from at the moment, there's definitely a strong case to be made for CRISPR Therapeutics, if only on its sickle cell/beta thalassemia results. However, I'd argue that investors would do better by taking a shotgun approach and holding a small basket of the top gene-editing stocks, including CRISPR, Editas, and Sangamo, among others.