ACUTE Lymphoblastic Leukemia (ALL) and COVID-19 Infection. a Campus ALL Report

Introduction. The recent spread of the COVID-19 infection has represented an important challenge in the management of acute lymphoblastic leukemia (ALL) patients.

Aims and methods. To investigate the incidence, features, source of contagion and outcome of patients with ALL who developed a COVID-19 infection, a survey was conducted among 34 hematology centers throughout Italy within the Campus ALL network. The period covered by the survey spanned from February 2020 to April 2021 and included 756 adult ALL patients actively followed during this time period.

Results. Sixty-three of the 756 ALL patients (8.3%) developed a COVID-19 infection, with an equal distribution among the various regions. The majority of cases (90.5%) was recorded during the second wave of the pandemic, between September 2020 and April 2021. The source of the infection was nosocomial in 26 cases (41.3%), familial in 23 (36.5%), unknown in 13 (20.6%) and work-related in 1 (1.6%).

The infected patients were prevalently male (n=43, 68.2%) with a similar distribution among age groups: 21 patients aged 18-35 years, 17 35-50, 15 50-65 and 10 older than 65. Seventeen patients (27%) had a diagnosis of T-ALL, 28 (44.4%) of Ph- B-ALL and 18 (28.6%) of Ph+ ALL. Thirty-six (57.1%) of the infected patients had no concomitant comorbidities, whereas 27 (42.9%) had one or more comorbidities.

The infection was documented at the onset of the disease in 4 patients (6.3%), during induction in 10 (15.9%), consolidation in 13 (20.6%), chemotherapy maintenance in 11 (17.5%), after allogenic transplant in 15 (23.8%), during maintenance with tyrosine kinase inhibitors (TKI) treatment or off-treatment in 8 (12.7%) and at relapse in 2 (3.2%). Of the infected patients, 9 were asymptomatic, 10 had only isolated fever, 36 had respiratory symptoms and 8 presented other symptoms, including - but not limited to - ageusia and anosmia. As a consequence, management of the infection was variable: 29 (46%) patients did not require hospitalization, 28 (44.4%) were hospitalized in a COVID ward and 13 of them required respiratory assistance; finally, 6 (9.5%) patients were transferred to an ICU. Importantly, in 54 patients (85.7%) there were no sequelae, in 1 patient a pulmonary fibrosis was documented and in 1 patient the delay in treatment led to a relapse of the disease, while 7 (11.1%) succumbed to the infection. Finally, in 6 cases (9.5%) the infection was still ongoing at the time of the survey, and at the last update (July 2021) it had resolved in all. Since a key aspect in the management of ALL is the adherence to the timing of treatment, we also investigated if COVID-19+ patients stopped treatment during the infection. Out of the 42 evaluable patients (patients who had undergone an allogeneic transplant or were off-treatment were excluded from this analysis), ALL treatment was suspended in 28 (66.6%). Importantly, while in Ph+ ALL only very few patients stopped treatment (3/12), in Ph- B-ALL the majority did interrupt it (18/22, p<0.001); likewise, also in T-ALL most patients suspended treatment (7/8).

Conclusions. The incidence of SARS-CoV-2 infection in adult ALL patients in Italy over a 15 month period has been similar to that observed in the general population and has been recorded mostly during the second wave of the pandemic. The contagion was mainly nosocomial, suggesting that outward care should be pursued as much as possible in ALL. The infection was manageable, with 46% of patients not requiring any medical intervention and an overall death rate of 11%. Strikingly, in line with previous reports ¹, it appears that Ph+ ALL patients were more manageable, with less treatment interruptions. These findings underline the advantage of the TKI-based induction/consolidation strategy without systemic chemotherapy in Ph+ ALL used in the GIMEMA (Gruppo Italiano Malattie EMatologiche dell'Adulto) protocols and further point to a possible protective role of TKIs in COVID-19-infected patients.

1. Foà R et al, Br J Haematol. 2020;190(1):e3-e5