Nowadays due to modern risk-adapted treatment protocols high survival rates have been achieved in patients with aggressive B-cell lymphomas, even at stages III–IV these indicators overrun 90 %. Mainly these successes were associated with the inclusion of rituximab in the standard chemotherapy regimens. As the follow up period of the patients is lengthened, it has become clear that ongoing treatment is associated with the development of immediate and long-term adverse effects of chemoimmunotherapy. In Russia and the world, there are multicenter studies aimed at studying prognostic factors that make it possible to reduce single and/or total doses of chemotherapy drugs, and therefore, to reduce chemotherapy toxicity. The obtained data allow considering the early complete antitumor effect (after 2 courses of therapy) as an advantage factor, so it is possible to reduce program chemoimmunotherapy intensity without reducing high patients survival rates.

The history of asparaginase clinical use is inextricably linked to the improvement of treatment programs for acute lymphoblastic leukaemia (ALL). Asparaginase, obtained from E. coli, has become the crucial part in the protocols for the treatment of ALL in children and adults since the 1960s-1970s due to its antitumor effect on lymphoid leukemia cells. Despite the evolution of therapeutic approaches in ALL management, changes in used chemotherapeutic agents, their administration regimens and doses, the asparaginase remains one of the leading therapeutic agents in ALL patients. With time ideas about the asparaginase mechanisms have expanded, new data have been accumulated on adverse effects (allergic reactions, thrombotic complications, pancreatitis, hepatic dysfunction, etc.). The asparaginase obtained from Erwinia chrysanthemi and PEGylated forms of the drug were used to reduce the frequency of any of such adverse effects. This literature review provides current concepts on the mechanism of L-asparaginase dosage forms action, describes side effects associated with the use of this medication. We also present our own clinical case of L-asparaginase (obtained from Erwinia chrysanthemi) administration in ALL patient with allergic reaction to PEG-L-asparaginase.

Introduction. So far there has been no clear protocol on the treatment of bacterial infections in hematopoietic cancer patients undergoing polychemotherapy (PCT) and hematopoietic stem cell transplantation (HSCT). Guidelines available from antibiotic therapy panels such as EMBT, NCCN, ECIL, Sepsis-3 often fail to cover the entire spectrum of clinical risk factors of severe complications caused specifically by multiresistant Klebsiella pneumoniae.The aim of the study — is to showcase the clinical experience of demonstration of the experience of the Research Institute of Pediatric Oncology and Hematology at N.N. Blokhin Russian Cancer Research Center with respect to adjusting antibacterial therapy for the spectrum of microorganisms found in the patient before the onset of antitumor therapy, and for the multiresistant microorganism findings in patients with blood cancers and febrile neutropenia (FN) undergoing PCT and HSCT.Materials and methods. The study involved five patients undergoing either PCT or HSCT for hematopoietic cancers at Research Institute of Pediatric Oncology and Hematology in October 2019 — October 2020, multiresistant Klebsiella pneumonia colonies found in each case. Results. Five patients with hematopoietic cancers and induced bone marrow aplasia were found to have multiresistant Klebsiella pneumoniae colonies on top of post-PCT/HSCT immunosuppression. Given high risk of death, these patients need early antibacterial therapy with reserve antibiotics outside standard empirical antibacterial treatment protocols should they develop FN. The Center's practices have shown that baseline protocols are often inadequate to the severity of these patients' conditions in a certain timeframe.Conclusions. To sum up the Center's limited experience, the finding is that additional research is required into the factors of risk of severe multiresistant Klebsiella pneumoniae infections in patients undergoing PCT and HSCT; algorithms must be developed for the treatment of patients in such a critical condition.