uniQure presented new hemophilia B clinical trial data on May 19, 2018 at the American Society of Gene and Cell Therapy (ASGCT) Annual Meeting in Chicago, IL. The data showed its hemophilia B investigational gene therapy candidate AMT-060 could be successfully delivered to patients with certain pre-existing antibodies. Individuals testing positive for “anti AAV5 neutralizing antibodies” (NABs), are often excluded from trials, as they were thought to impede the delivery of some gene therapies. AAV5 is a variant of the type of the adeno-associated virus (AAVs) vectors that are being investigated in multiple gene therapy trials.
uniQure’s proprietary, variant AAV5 are very small viruses that do not actually cause disease, nor do they typically produce mild immune responses. Instead, AAV5 delivers functioning genes into the liver cells, in this case the factor IX (FIX) gene for patients with hemophilia B. The goal of the trial is to prompt long-term FIX protein production through a single administration of the therapy. This could dramatically reduce the frequency of bleeding episodes in people with hemophilia B.
Study investigators re-analyzed pre-treatment blood serum samples of the ten patients in the phase I/II clinical trial of AMT-060 and found that no relationship was detected between the presence NABs and clinical outcomes of AMT-060 in patients with hemophilia B.
“These important data presented at ASGCT bolster our confidence that AAV5 gene therapies can provide successful liver transduction in all or nearly all patients,” stated Sander van Deventer, MD, PhD, chief scientific officer of uniQure. “The study suggests that, in contrast to experience with other AAV vectors, detectable pre-existing neutralizing antibodies do not prevent successful gene transfer using AAV5 at clinical doses. In patients pre-exposed to AAV5 who tested positive for anti-AAV5 antibodies, therapeutic transgene expression was established with no cellular immune response observed after systemic administration of AAV5."
Source: uniQure press release dated May 21, 2018