Shares of the gene-editing titan CRISPR Therapeutics (CRSP -2.26%) are seemingly in for a bad day. The biotech's stock dropped by nearly 10% in premarket trading today in response to an early look at phase 1 trial results for its blood cancer candidate CTX110.
CRISPR Therapeutics announced that this off-the-shelf CAR-T cell therapy produced a 58% overall response rate and a 38% complete response rate (no detectable signs of cancer) in a cohort of patients with large B-cell lymphoma treated with a single dose of CTX110. Equally important, the company noted that the observed side effects from the therapy were generally mild in nature.
Most importantly, CRISPR Therapeutics said there were no grade 3 or higher cytokine release syndrome events in the trial. This serious and potentially life-threatening safety issue has plagued autologous CAR-T therapies such as Novartis' Kymriah and Gilead Sciences' Yescarta.
The biotech's stock has rebounded to some degree since the official start of today's trading session. But the company's shares are still down by a noteworthy 7% as of 9:58 a.m. EDT Wednesday morning.
CRISPR Therapeutics, for its part, said that these initial results were encouraging enough to potentially advance the therapy into a registrational trial. That trial could kick off as soon as the first quarter of next year, according to the company's press release.
So why is the biotech's stock sinking today in the wake of this clinical update? Investors apparently aren't thrilled about CTX110's durability. The company reported that 21% of patients in this early-stage trial were cancer-free at the six-month mark. Unfortunately, patients in trials for autologous CAR-T therapies from Novartis and Gilead exhibited durability rates (cancer-free after six months) of between 29% and 40%.
So, at this way too early juncture, CRISPR Therapeutics' off-the-shelf CAR-T therapy looks to be safer than the approved treatments from Novartis and Gilead Sciences, but it might be less effective overall. At least that seems to be the message some investors are walking away with today, given the biotech stock's poor reaction to this news.
The company, though, thinks changes to the dosing regimen in the upcoming pivotal trial could dramatically boost the therapy's durability. If true, CRISPR Therapeutics' could have a game changer on its hands in the realm of genetically modified cell therapies for cancer. CTX110, after all, might turn out to be safer and far easier to manufacture than the current generation of CAR-T therapies. Aggressive investors, in turn, might want to take advantage of this dip.