A closer look at conditioning
Conditioning is an essential step to optimize treatment. It’s used to prepare the patient’s body to receive the gene therapy. Conditioning helps the stem cells carrying the therapeutic gene to engraft in the patient’s bone marrow, where they will divide and proliferate into trillions of daughter cells. Each of those cells is expected to carry the therapeutic gene and be capable of expressing the active protein the patient needs throughout the body and brain. This engraftment is crucial for the gene therapy to be successful.
We currently use a medication called busulfan to enable a personalized conditioning regime with precision dosing. Busulfan is a clinically validated conditioning agent that has been used, both in academia and industry, as a single agent in a single cycle for hundreds of patients treated with investigational lentiviral gene therapies.
The conditioning process is associated with known side effects and does have risks. For instance, patients are more vulnerable to infection and bleeding for several weeks after conditioning. They may experience transient side effects such as fatigue, nausea, hair loss and mouth sores. There may be long-term risks to fertility; individuals undergoing conditioning may be advised to freeze their eggs or sperm in advance of the treatment.
We deploy a personalized medicine approach involving daily blood monitoring to assess the rate of busulfan metabolism and precisely adjust the next day’s dose accordingly. This process potentially allows us to maximize the effectiveness of conditioning — and the likelihood of successful engraftment — while minimizing the side effects.
At AVROBIO, we are committed to a process where each patient receives a personalized therapeutic approach and we are excited to have the opportunity to be a leader in this next frontier for lentiviral gene therapy.
Learn more about our commitment to individuals living with genetic disorders.