Improved outcomes of large B-cell lymphoma patients treated with CD19 CAR T in the UK over time

The success of CD19 Chimeric antigen receptor (CAR) T-cell therapy in large B-cell lymphoma (LBCL) has been partially offset by toxicity and logistical challenges, which off-the-shelf agents like CD20xCD3 bispecific antibodies might potentially overcome. However, when using CAR T outcomes as the 'standard-of-care comparator̕ for relapsed/refractory (r/r) LBCL, a potential learning curve with implementing a novel, complex therapy like CAR T needs to be considered. To address this, we analysed 726 UK patients intended to be treated with CD19 CAR T for r/r LBCL and compared outcomes between the first year of the national CAR T programme (Era 1; 2019) and the more recent treatment era (Era 2; 2020-2022). We identified significant improvements for Era 2 versus Era 1 in dropout rate (17% vs. 27%, p = 0.001), progression-free survival (1-year PFS 50% vs. 32%, p < 0.001) and overall survival (1-year OS 60% vs. 40%, p < 0.001). We also observed increased use of bridging therapy, improvement in bridging outcomes, more tocilizumab/corticosteroid use, reduced high-grade cytokine release syndrome (4% vs. 9%, p = 0.01) and intensive care unit admissions (20% vs. 32%, p = 0.001). Our results demonstrate significant improvement in CAR T outcomes over time, highlighting the importance of using up-to-date clinical data when comparing CAR T against new treatment options for r/r LBCL.

Haemotoxicity of chloramphenicol succinate in the CD-1 mouse and Wistar Hanover rat

1. Chloramphenicol has been widely used in the treatment of serious infections including typhoid fever and meningitis. However, the drug is haemotoxic in man inducing firstly, a reversible, dose-dependent anaemia which develops during treatment, secondly, an often fatal aplastic anaemia with pancytopenia and acellular marrow, and thirdly, leukaemia. 2. We investigated the haemotoxicity of chloramphenicol succinate (CAPS) in female CD-1 mice in repeat dose studies, to compare the response with the reversible anaemia reported in man. Studies in male Wistar Hanover rats were also carried out. 3. CAPS was gavaged daily to mice at dose levels from 800 - 2000 mg/kg for seven days. Values were significantly reduced for reticulocytes at 1700 and 2000 mg/kg, and for erythrocytes (RBC), haematocrit (HCT), and haemoglobin (Hb) at 2000 mg/kg. Platelet and white blood cell (WBC) counts were unaffected. 4. Mice were dosed with CAPS at 1400 mg/kg for 10 days and sampled at 1, 4 and 15 days after the last dose. At day 1 post dosing, RBC, HCT and Hb values were significantly reduced, but returned to normal (or above normal) by day 4 or 15. 5. CAPS from 2000 - 4000 mg/kg was gavaged to rats daily for 19 days. Hb values were significantly lower at 3600 and 4000 mg/kg; reticulocytes were not reduced. WBC and platelet counts, in general, were unaffected. 6. Levels of apoptosis in marrow mononuclear cells were increased in CAPS-treated mice, but not in CAPS-treated rats. Serum biochemistry parameters, in general, showed few changes of toxicological significance. 7. We conclude that the administration of CAPS to CD-1 mice induced haematological changes showing close parallels with the chloramphenicol-induced reversible anaemia seen in man.