Shares of companies developing CRISPR-based therapies slid Monday after STAT News reported two new studies showed edited cells might cause cancer.
Gene editing tool CRISPR-Cas9 has been hailed as a breakthrough that could allow scientists to treat and possibly even cure genetic diseases. In two studies published Monday in the journal Nature Medicine, researchers found editing cells' genomes with the technique might increase the risk of cancer. Those edited cells are those ones that are intended to treat diseases.
The new research could pose a major setback to the treatment. STAT's report on the findings sent some biotech stocks tumbling Monday.
Shares of CRISPR Therapeutics tanked nearly 13 percent, shares of Editas Medicine dropped nearly 8 percent, shares of Intellia Therapeutics fell nearly 10 percent, while shares of Sangamo Therapeutics shed more than 5 percent.
"We do not believe the theoretical risks described in these papers apply to CRISPR Therapeutics' programs," the company said in a statement to CNBC. "We apply CRISPR for gene disruption or high-efficiency gene correction, neither of which are the focus of these reports. In any case, we seek to evaluate all potential risks carefully and assess thoroughly as we advance our programs to the clinic."
Intellia Therapeutics said in a statement it has "observed no signs of this type of toxicity or cells transforming into cancer or tumors in Intellia's in vivo and ex vivo programs."
Lukas Dow, a cancer researcher who uses CRISPR at Weill Cornell Medicine, told CNBC it's "definitely worth paying attention to these effects, but a long way from a deal-breaker."
The papers focused on a gene that encodes for a protein called p53 that's important for tumor suppression, and one of the studies, from the Karolinska Institutet in Sweden, suggested "p53 inhibition may improve the efficiency of genome editing" in certain cells, and that "p53 function should be monitored when developing cell-based therapies utilizing CRISPR-Cas9."
In response, a spokeswoman for Editas said in a statement that "p53 induction in response to DNA damage is a normal and expected response to DNA damage," and that inhibiting p53 could lead to "the accumulation of unwanted mutations from non-CRISPR mechanisms."
"Thus, for making medicines," the statement from Editas concluded, "we do not believe p53 suppression is appropriate or needed to achieve high levels of gene correction."
Editas didn't respond to additional questions.