Susana Rives
Specialist doctor in charge of the Leukaemia and Lymphoma Unit at the Paediatric Oncology Department of the Hospital Sant Joan de Déu Barcelona.
The study is of good quality and very important.
80-90% of children with acute lymphoblastic leukaemia can be cured with chemotherapy. However, the prognosis in infants (babies under 12 months) is much worse, with a chance of cure of less than 60%. Over the past 20 years, these results have not improved.
This international study shows that adding blinatumomab (a type of immunotherapy) to chemotherapy is safe and is associated, at least in the short term, with a large improvement in survival in infants (babies under 12 months) with acute lymphoblastic leukaemia.
When comparing the results of this study with those obtained in previous studies that did not use blinatumomab, the probability of disease-free survival at two years increases from 49.4% to 81.6%. Although more follow-up time is needed to speak of cure, it should be noted that among infants who relapsed, the vast majority (90%) did so within the first two years.
Blinatumomab had already been shown to be a safe and effective drug in children older than 1 year and adults with relapsed or poorly responsive acute lymphoblastic leukaemia (persistence of minimal residual disease). It was not known whether it would be effective and tolerated in infants. One of the possible side effects of blinatumomab is nervous system toxicity (such as tremor, seizures). In infants, it was important to rule out that it might be worse tolerated. In 30 patients, none have had to discontinue treatment due to neurological toxicity or otherwise.
The implication is great, as it makes it advisable to use blinatumomab in the treatment of infants with ALL.
The limitations are that it is a study with a small number of patients (30 infants) and that there has not been a randomised comparison of treatment with chemotherapy alone versus chemotherapy + blinatumomab. However, given the poor prognosis of these children with chemotherapy and the data on blinatumomab in children older than 1 year and adults, it was very difficult (ethically) to randomise whether or not to give blinatumomab. On the other hand, even though 30 is a small number, leukaemia in children under 1 year is a very rare type of leukaemia and makes it difficult to have high numbers in a short time.
It will be able to benefit 80% of infants with acute lymphoblastic leukaemia. In absolute numbers this is a very low number, because the incidence of ALL in infants is very small. But among patients with this minority disease, it will benefit most of them.
The follow-up time is short and it is true that it will have to be confirmed with results at longer follow-up. However, it is a very aggressive type of leukaemia and most relapses and deaths due to toxicity occur in the first two years, so it is a result that deserves to be taken into account and this treatment should be included in the first line of treatment. However, it will be necessary to re-evaluate, with further follow-up, whether these promising results are maintained.