BHUBANESWAR: In a significant medical breakthrough, India's first human gene therapy with a lentiviral vector for severe haemophilia-A has been found to be successful with zero bleeding rate in a group of patients.
Haemophilia is a serious bleeding disorder caused by blood deficiency of clotting factors (factor VIII and factor IX proteins). It can lead to spontaneous bleeding episodes, joint damage and a reduced quality of life for patients and their families.
The newly designed gene therapy has shown promising results during the first phase trial on five patients, aged between 22 and 41. The annualised bleeding rate has been observed to be zero for all five patients over a cumulative follow-up of 81 months.
As part of the human gene therapy, stem cells were extracted from the blood of the patients and after certain gene corrections, the cells were again transplanted with a lentiviral vector in the respective patients.
A distinctively prepared lentiviral vector having no capacity for new infection and self-replication was used in the gene therapy. The therapy provided the body with the ability to produce factor VIII, ensuring that there is no need for repeated infusions.
Supported by the Department of Biotechnology, this first-in-human gene therapy for haemophilia-A patients has been developed by the Centre for Stem Cell research (CSCR) at CMC, Vellore. Results of a study conducted on the patients, who had undergone the therapy, have been published in the recent edition of the prestigious peer-reviewed New England Journal of Medicine.
Lead author of the study and head of the haematology research unit at St Johns Research Institute, Bengaluru Dr Alok Srivastava said excellent outcomes were observed in median factor-VIII levels, which were assessed during the treatment, and follow-up for a period of around two years.
"No spontaneous bleeding events occurred in any patient during or after the gene therapy. Before the therapy, all patients had reported an annualised bleeding rate of at least 20 events. The results of this clinical study reveal a new opportunity for gene therapy for haemophilia A that can be offered to all patients, possibly at an early age," Dr Srivastava said.
Even though haemophilia is a rare disorder, India has the world's second largest burden with a case load of 1.36 lakh. Severe haemophilia-A is usually managed with factor-VIII protein replacement or hemostatic products that prevent bleeding.
A senior scientist at Bhubaneswar-based Institute of Life Sciences (ILS) Dr Rajeeb Swain said the available procedures have few takers due to the high cost of treatment and difficulty in gaining access to a patient's bloodstream through their veins, especially in children. "The gene therapy will be very useful against some blood disorders that were incurable earlier," he said.
The study was conducted at CMC and the Centre for Stem Cell Research, a unit of inStem in Bengaluru. The therapy will soon go under a second phase human trial at selected centres.