Clinical observation of hypofibrinogenemia induced by the treatment of tocilizumab in rheumatic diseases and exploration of risk factor for hypofibrinogenemia

Pharmacovigilance analysis of drug-induced hypofibrinogenemia using the FDA Adverse Event Reporting System

BACKGROUND

Drug-induced hypofibrinogenemia has received increasing scrutiny; however, the specific drugs involved remain poorly characterized. Hypofibrinogenemia can have significant clinical implications, including increased bleeding risks.

AIM

This study aimed to utilize the FDA Adverse Event Reporting System (FAERS) to identify and analyze drugs frequently implicated in drug-induced hypofibrinogenemia.

METHOD

A disproportionality analysis was conducted using FAERS data from January 2004 to March 2024. Various statistical tools were used, including the Reporting Odds Ratio (ROR), Proportional Reporting Ratio, Medicines and Healthcare Products Regulatory Agency metrics, and Bayesian confidence propagation neural network.

RESULTS

The analysis included 17,627,340 cases involving 52,373,206 adverse events, with 1,661 cases identified as hypofibrinogenemia. The top five drugs associated with hypofibrinogenemia by case number were methotrexate (124 cases), tigecycline (119 cases), tocilizumab (100 cases), pegaspargase (83 cases), and alteplase (57 cases). The drugs ranked by signal strength based on ROR included eravacycline (ROR 2173.84, 95% CI 1208.80-3909.30), tigecycline (ROR 747.34, 95% CI 619.03-902.24), crotalidae polyvalent immune Fab (ROR 407.67, 95% CI 291.07-570.99), pegaspargase (ROR 216.06, 95% CI 173.15-269.61), and asparaginase (ROR 184.93, 95% CI 132.18-258.72).

CONCLUSION

This analysis of FAERS data identified 52 drugs associated with hypofibrinogenemia, most (88.5%) of which do not mention this risk in their prescribing information. These findings demonstrate the need for the monitoring of blood fibrinogen and may serve as a reference for the explore of the characteristics and underlying mechanism of drug-induced hypofibrinogenemia in the real world.

Characteristics, risk factors and a risk prediction model of tocilizumab-induced hypofibrinogenemia: a retrospective real-world study of inpatients

OBJECTIVE

The occurrence of hypofibrinogenemia after tocilizumab treatment has attracted increasing attention, which may cause bleeding and even life-threatening. This study aims to explore the risk factors for tocilizumab-induced hypofibrinogenemia (T-HFIB) and construct a risk prediction model.

METHODS

A total of 221 inpatients that received tocilizumab from 2015 to 2023 were retrospectively collected and divided into T-HFIB group or control group. The risk factors for T-HFIB were obtained by logistic regression equation and used to establish the nomogram.

RESULTS

T-HFIB was observed in 121 of 221 patients (54.75%). Multifactorial logistic regression analysis revealed that infection (OR = 2.002, 95%CI:1.018 ~ 3.935), COVID-19 (OR = 3.752, 95%CI:1.264 ~ 11.139), CAR-T therapy (OR = 4.409, 95%CI:2.017 ~ 0.894), and concomitant glucocorticoids (OR = 5.303, 95%CI:0.227 ~ 0.894) were identified as independent risk factors for T-HFIB, while high baseline fibrinogen level (OR = 0.813, 95%CI:0.670 ~ 0.988) and concomitant antirheumatic drugs (OR = 0.451, 95%CI:0.227 ~ 0.894) were identified as protective factors. A nomogram was established, and area under the curve (AUC) of prediction model was 0.772 (95%CI:0.709 ~ 0.836). Calibration curve showed a good prediction accuracy for the occurrence of T-HFIB.

CONCLUSION

The infection, COVID-19, CAR-T therapy, and concomitant glucocorticoids were independent risk factors for T-HFIB, while high baseline fibrinogen and concomitant antirheumatic drugs were protective factors. This nomogram can help early identify the patients at potential high risk of developing T-HFIB.

Evaluation of tocilizumab-induced hypofibrinogenemia in rheumatology practice: a retrospective, real-life, single-center experience

Tocilizumab (TCZ) which is a humanized interleukin (IL)-6 receptor antibody has been increasingly widespread used in rheumatology practice. TCZ-related hypofibrinogenemia is a not well-described side effect, but awareness seems to be incresing as publications on this topic are also becoming more frequent. Our aim in this study was to determine the frequency, timing, and approach to TCZ-related hypofibrinogenemia in rheumatic diseases. We retrospectively screened our patients who received TCZ for inflammatory rheumatic diseases and studied serum fibrinogen at least once before and/or after drug administration. We recorded and analyzed demographic features (age, gender, diagnosis), comorbidities, laboratory parameters, management, and outcome data. 30 patients who received TCZ due to rheumatological diseases and had at least one fibrinogen level were included in this study. 73.3% were female and median age was found to be 65 (42-82) years, with median disease duration of 148 (36-500) months. 90% of the patients received TCZ for RA and 10% for GCA. We examined the fibrogen levels at an average of 24 months (min 1 max 108) following the start of TCZ treatment. The study group was divided into those with normal fibrinogen levels (normal fibrinogen group) and those with low fibrinogen levels (lowfibrinogen group). In total, hypofibrinogenemia was found in 14 (46.6%) patients. Median serum fibrinogen level in the low fibrinogen group after TCZ was calculated to be 151.5 mg/dl (min 92 max 171). Most patients were asymptomatic (71.4%). Ecchymoses were in seen 4 (28,6%) patients. No major bleeding were seen. TCZ was discontinued in 5 out of 14 patients (35.7%), while 9 out of 14 patients (64.3%) were closely followed. Outcomes regarding fibrinogen levels (11 out of 14) were as follows: increase in 4 and not checked in one after cessation of the drug, 3 spontaneous increases under the drug, and 3 persistently low levels on TCZ treatment. We found no difference in terms of gender (p = 0.417), platelets (p = 0.343), ESR (p = 0.448), and CRP (p = 0.660) at the time of TCZ initiation between groups. TCZ-related hypofibrinogenemia is more frequent than expected with occurence in both the early and late stages of treatment. Further research is required to determine whether to regularly measure fibrinogen levels in patients using TCZ and how to treat patients with hypofibrinogenemia.