The Role of Allograft in Acute Lymphoblastic Leukaemia, Including Alternate Donors

Abstract

The management of acute lymphoblastic leukaemia (ALL) remains challenging. The changing landscape of newer agents and combinations of chemotherapy are improving outcomes, and various conditioning regimens and possible donor sources for allogeneic transplant provide management options; allograft remains the most potent anti-leukaemia therapy available. With improvements in treatments and monitoring of disease response, allogeneic transplantation is becoming more refined as an important option for selective patients with difficult disease. Although the paediatric ALL protocols used for adolescents and young adults are now extended towards the middle-aged patients, and newer therapeutic agents may be incorporated, there is evolving data comparing short and long-term outcomes and deliverability of treatment. Reliance on registry transplant data is inadequate in guiding optimal therapy for the individual, who may have a variety of specific needs. With the limited clinical trials in this field, it is important to continue reviewing progress and outcomes with alternative stem cell sources, such as mismatched unrelated donors, haploidentical donors, and cord blood transplants, which may cure many patients, though carry risks of treatment-related mortality and morbidity. Conditioning regimens of reduced toxicity have enabled the older and higher risk patients to proceed to allograft, but it remains hazardous. It is important to understand the features of the malignant cells, response to therapies, individual patient factors, donor stem cells available, and patient’s wishes, to help craft the current management. Allogeneic transplantation remains a very important option for ALL, and patient selection and path to transplant are continuing to evolve and be guided by ongoing clinical and laboratory data, including minimal residual disease assessment.