Clinical Hold - Hemophilia B

uniQure's hemophilia B program has been placed on clinical hold by the U.S. FDA

In December 2020 we announced that our hemophilia B gene therapy program, including the pivotal, Phase III HOPE-B study, has been placed on clinical hold by the U.S. Food and Drug Administration (FDA). Patient dosing is complete in each of uniQure’s three hemophilia B gene therapy studies, and there is no plan to enroll or treat additional patients. In March 2021 we announced findings from the investigation.

The clinical hold was initiated following the submission of a safety report in mid-December relating to a possibly related serious adverse event associated with a preliminary diagnosis of hepatocellular carcinoma (HCC), a form of liver cancer, in one patient in the HOPE-B trial that was treated with etranacogene dezaparvovec (AMT-061). The patient has multiple risk factors associated with HCC, including a twenty-five-year history of hepatitis C (HCV), hepatitis B virus (HBV), evidence of non-alcoholic fatty liver disease and advanced age. Chronic infections with hepatitis B and C have been associated with approximately 80% of HCC cases.

On March 29, 2021, we announced the results of a comprehensive investigation that found that it is highly unlikely the HCC was caused by etranacogene dezaparvovec (AMT-061) (view press release).  The investigation included multiple analyses conducted by an independent laboratory and reviewed by external experts.  These studies have shown no evidence to suggest that the AAV vector delivered to this patient has played a pathogenic role in the patient’s HCC.

Data from the investigation were submitted to the FDA on March 26.  We are prepared to discuss with the FDA the recently submitted analyses and the status of the clinical hold as expeditiously as possible. 

Patient safety will always be our top priority.  All patients in uniQure’s hemophilia B gene therapy program, including the 54 patients in the HOPE-B trial, have now had abdominal ultrasounds performed one year after dosing, and each will continue to be monitored by their care teams.  No other cases of HCC have been reported in uniQure clinical trials conducted in more than 100 patients in hemophilia B and other indications, with some patients dosed more than 10 years ago.


If you are a healthcare professional outside of the U.S. interested in more information on uniQure’s clinical trials, please visit our Clinical Trial Information page or contact us at 

> HOPE-B Trial of AMT-061 in Severe or Moderately Severe Hemophilia B Patients