US regulators have issued an accelerated approval for use of Amgen's immunotherapy Blincyto to treat paediatric patients with Philadelphia chromosome-negative (Ph-) relapsed or refractory B-cell precursor acute lymphoblastic leukaemia (ALL).

ALL is a rare and rapidly progressing cancer of the blood and bone marrow, and is the most common type of cancer in children. Of around 2,500 US children and adolescents diagnosed with B-cell precursor ALL each year, 15-20 percent will experience relapse or fail to achieve remission, highlighting the need for new treatment options.

Blincyto (blinatumomab) won conditional approval in the US back in 2014 for Ph- precursor B-cell ALL; the application to expand its treatment scope is based on data from a Phase I/II trial in 93 paediatric patients with relapsed or refractory forms of the disease, which met its primary endpoint of complete remission within the first two cycles of treatment.

No new safety concerns revealed by the study, and subjects are now being monitored for long-term efficacy.

"Children with relapsed or refractory ALL have very poor long-term outcomes and currently there are limited available therapies to induce remission," said Sean Harper, executive vice president of R&D at Amgen, earlier this year.

"We look forward to collaborating with regulatory authorities to make Blincyto available to this ultra-orphan patient population with a high unmet medical need."