Gene Therapy AMT-060 for Hemophilia B Gains PRIME Designation in Europe

Margarida Azevedo, MSc avatar

by Margarida Azevedo, MSc |

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UniQure‘s investigational gene therapy AMT-060 for severe hemophilia B has received PRIME designation by the European Medicines Agency (EMA).

The EMA designation was based on the results of a Phase 1/2 open-label, dose-escalating study of AMT-060 (NCT02396342). The study included 10 patients, each receiving AMT-060 intravenously for 30 minutes. One group of five patients received a lower dose of AMT-060 and another five participants received a higher dose. The study is expected to be completed in December 2020.

Initial results show the treatment resulted in sustained improvement for all patients in the lower dose groups, with stable levels of factor IX (FIX) gene activity at up to 12 months of follow-up. Patients’ spontaneous bleeding episodes nearly stopped, the study found.

“We are very pleased to have AMT-060 for hemophilia B accepted into the PRIME program,” Matthew Kapusta, CEO of uniQure, said in a press release. “Similar to the Breakthrough Therapy designation that AMT-060 received from the U.S. Food and Drug Administration earlier this year, we look forward to this enhanced collaboration with the EMA to advance the clinical development of  this potentially transformative therapy for hemophilia B patients.”

PRIME is designed to aid and expedite the regulatory process for investigational drugs that target an unmet medical need and may offer a major therapeutic advantage over existing medicines.

In December, the company presented the study results at the 58th American Society of Hematology Annual Meeting (ASH 2016) in San Diego. The data included the results of up to 52 weeks of follow-up in the lower-dose patient group, and of up to 31 weeks of follow-up in the higher-dose group.

The five patients in the low-dose group continued to maintain good levels of FIX activity 52 weeks following the treatment. These patients had been unable to control their bleeding episodes despite being treated with preventive therapies. In the last 14 weeks of follow-up, they had no more spontaneous bleedings, the company reported.

Results from the five patients in the higher-dose group showed that treatment with AMT-060 caused a significant improvement in their disease. Four of these patients, who previously needed chronic replacement therapy, were discontinued from their preventive FIX infusions. So far, only one patient experienced a spontaneous bleed after discontinuation of prophylactic FIX replacement therapy.

In terms of safety, treatment with AMT-060 is being well-tolerated in this clinical trial, with no patients experiencing adverse events, the company said. Two patients in the higher-dose group and one patient in the low-dose group experienced elevations of alanine aminotransferase (ALT, a liver enzyme), but these were mild and were successfully treated with corticosteroids. These elevations in ALT were not related to loss of treatment effectiveness.

AMT-060 was granted breakthrough therapy designation by the U.S. Food and Drug Administration (FDA) in January for patients with severe hemophilia B.