What happened

Shares of the gene therapy company uniQure N.V. (QURE 9.35%) are down by a noteworthy 16% as of 12:33 p.m. EST Monday. The biotech's shares are tanking today in response to a clinical hold by the Food and Drug Administration (FDA) on its late-stage hemophilia B gene therapy known as etranacogene dezaparvovec (aka AMT-061).

The hold stems from the submission of a safety report in mid-December over a suspected case of liver cancer in one patient enrolled in the therapy's pivotal trial dubbed "HOPE-B." The patient in question was reportedly dosed in October 2019.  

A man with a look of shock on his face standing in front of a downward trending chart.

Image source: Getty Images.

So what

uniQure noted in its press release that the patient has multiple risk factors for this particular form of liver cancer, including hepatitis C, hepatitis B, possible non-alcoholic fatty liver disease, and advanced age. Therefore, this malignancy may not be treatment-related. This may, instead, be a case of the FDA simply taking a cautious approach.

The agency's trepidation is certainly understandable, however. Gene therapy has a long history of troubling safety issues in general. Investors, though, may be overreacting to this clinical hiccup. After all, no other cases of liver cancer have been detected in the company's hemophilia B program, despite 100-plus patients being dosed to date. 

Now what

Is uniQure a bad news buy? Clinical holds are tricky from an investing perspective. It will take time to unravel any potential causal relationship between this gene therapy treatment and a singular case of liver cancer. Meanwhile, investors are sure to grow restless while this process plays out. Simply put, it might be best to take a wait-and-see approach with this beaten down biotech stock for the time being.