Toxicities associated with chemotherapy regimens containing a fluoropyrimidine: A real-life evaluation in France.

AIMS: Despite fluoropyrimidines (FPs) constituting the main component of the chemotherapy combination protocols in 50% of chemotherapies for solid tumour treatments, incidence data for FP-related toxicity are poorly documented in real life. This study evaluated the number of patients receiving FP-based chemotherapies in France, along with the true incidence of FP-related serious adverse effects (SAEs) before the recent mandatory dihydropyrimidine dehydrogenase (DPD)-screening was introduced by French health authorities, DPD being the rate-limiting enzyme of 5-fluorouracil (5-FU) catabolism. METHODS: Exhaustive data on the number of patients treated with FP-based chemotherapy in 2013-2014 were collected in the Centre-Val de Loire region of France. True incidence of SAEs was extracted from a cohort of 513 patients with incident solid tumours receiving first-line FP-based chemotherapy. RESULTS: After extrapolation at national level, we estimated that 76,200 patients are currently treated annually with 5FU (53,100 patients, 62% digestive system-related versus 26% breast cancers versus 12% head and neck cancers) or capecitabine (23,100 patients, 45% digestive system-related versus 37% breast cancers versus 18% non-documented). Earlier (in the first two cycles) the SAE incidence rate was 19.3% (95% confidence interval (CI) 16-23%) including one toxic death (0.2%, 95%CI 0-1%). SAE incidence rate was 32.2% (95%CI 28-36%) over the first 6 months of treatment. Incidence of death, life-threatening prognosis or incapacity/disability was 1.4% (95%CI 0.4-2.4%) and 1.6% (95%CI 0.5-2.6%) during first two cycles and first 6 months, respectively. CONCLUSION: These data highlight the significant public health issue related to FP toxicity, with around 1200 patients developing FP-related life-threatening prognosis or incapacity/disability annually in France, including 150 toxic deaths. It is hoped that DPD-deficiency screening will reduce such iatrogenic events and eradicate toxic deaths.

Rituximab-induced serum sickness is more frequent in autoimmune diseases as compared to hematological malignancies: A French nationwide study.

INTRODUCTION: Rituximab induced serum sickness (RISS) is a rare delayed hypersensitivity reaction. The aim of this study was to describe the epidemiological and clinical characteristics of the RISS cases reported in France. METHOD: Serum sickness cases involving rituximab were identified from the French PharmacoVigilance Database from 1998 to 2016. RESULTS: We analyzed 37 cases of RISS. Rituximab was prescribed for an autoimmune disease in 78% of cases. Serum sickness occurred mainly after the first injection (54%) with a median time to onset of 12 days. The most frequent manifestations were rheumatologic symptoms (92%), fever (87%), and skin lesions (78%). The incidence was significantly higher when rituximab was used for autoimmune diseases than for a hematological malignancies. Taking into account the existence of a Systemic Lupus Erythematosus (SLE) as the indication of rituximab or as a comorbidity, the incidence of RISS in patients with SLE was even higher. DISCUSSION: We report on the largest series of RISS studied to date and confirm that this reaction preferentially occurs in patients with autoimmune disease, especially SLE. This may be due to B-cell lysis, leading to the release of intracellular antigens into the serum and subsequent antigen-antibody complex formation, especially in patients with elevated autoantibody production. This could also explain why RISS often occurred after a single injection. CONCLUSION: Patients generally recovered from RISS rapidly without obvious benefit from corticosteroid therapy. The risk of recurrence should prompt clinicians to question the use of rituximab after an episode of RISS.