Immune checkpoint inhibitor-induced acquired haemophilia: A pharmacovigilance analysis of the FDA adverse event reporting system

PD-1/PD-L1 inhibitor-induced immune thrombocytopenia: A pharmacovigilance study and systematic review

INTRODUCTION

Programmed cell death-1 (PD-1) and programmed cell death ligand-1 (PD-L1) immune checkpoint inhibitors (ICIs) are used for a variety of cancers and are associated with a risk of developing immune-related adverse events, most commonly dermatitis, colitis, hepatitis, and pneumonitis. Immune-mediated hematologic toxicities have been reported, but are less well-described in the literature. Immune thrombocytopenia (ITP) is a rare autoimmune, hematologic adverse event that has been reported with PD-1/PD-L1 inhibitors.

METHODS

We performed a retrospective observational analysis of the United States Food and Drug Administration Adverse Event Reporting System (FAERS) data. We searched for cases of ITP reported with exposure to PD-1/PD-L1 inhibitors from initial FDA approval for each agent to September 30, 2022. Disproportionality signal analysis was done by calculating the reporting odds ratio (ROR). Oxaliplatin was used as a positive control for sensitivity analysis as it is an anticancer therapy that has been associated with drug-induced ITP. A systematic review of the PubMed database was also conducted to identify published cases of PD-1/PD-L1 inhibitor-induced ITP.

RESULTS

There were 329 reports of ITP with ICIs in the FAERS database that were reviewed for a disproportionality signal, including atezolizumab (n = 27), durvalumab (n = 17), nivolumab (n = 160), and pembrolizumab (n = 125). The ROR was significant for atezolizumab (ROR 5.39, 95 % CI 3.69-7.87), avelumab (ROR 10.32, 95 % CI 4.91-21.69), durvalumab (ROR 7.91, 95 % CI 4.91-12.75), nivolumab (ROR 9.76, 95 % CI 8.34-11.43), and pembrolizumab (ROR 12.6, 95 % CI 10.55-15.06). In our systematic review, we summated 57 cases of ICI-induced ITP. Nivolumab and pembrolizumab had the most reported cases of ITP in the literature. Most cases reported (53 %) included ITP-directed therapies beyond corticosteroids for the management of ICI-induced ITP.

CONCLUSION

There is a significant reporting signal of ITP with several ICI agents. Clinicians should be aware of and monitor for signs of this potentially serious adverse event.

Rare Immune-Related Adverse Events (irAEs): Approach to Diagnosis and Management

Immune checkpoint inhibitors (ICIs) have revolutionised the treatment landscape across many solid organ malignancies and form part of routine clinical practice in many tumours. As indications for monotherapy, doublet therapy and combination approaches with chemotherapy and targeted agents expand, clinicians must be aware of the wide range of possible immune-related adverse events (irAEs). Common toxicities, including rash, colitis, hepatitis and pneumonitis are well described in the literature, and have established diagnostic and management algorithms. Rarer toxicities, often with an incidence of less than 1%, are less defined. These syndromes can be poorly recognised, may take on a fulminant course and do not have established or evidence-based diagnostic and management strategies. As such, patients may experience increased morbidity, mortality and poorer outcomes, related both to these irAEs as well as how the treatment of these may affect the management of their underlying malignancy. In this review, we aim to explore the incidence, potential biomarkers, pathogenesis, diagnostic work-up and clinical sequelae of a selection of uncommon irAEs, with a focus on myocarditis, neurological and haematologic syndromes. Further prospective research is required to accurately define the incidence and pathogenesis of these conditions, with the aim of increasing clinician awareness of rare irAEs and to assist with a more personalised and mechanism-based approach to these syndromes.

Acquired bleeding disorders secondary to immune checkpoint inhibitors: a case report and systematic literature review

Acquired bleeding disorders because of an autoimmune phenomenon are rare events. Acquired von Willebrand disease (aVWD) has been estimated as having a prevalence of 400 per million in the general population. Acquired hemophilia A (AHA), the most common of the acquired hemophilias, has an estimated incidence of 1.3-1.5 cases per million per year. Immune checkpoint inhibitors (ICI) targeting PD-1, PD-L1, and CTLA-4 are being used with increasing frequency for hematologic and oncologic disorders. Acquired hemophilias and aVWD have been reported with the use of ICI therapy. We performed a systematic review of the literature to identify cases of acquired bleeding disorders with ICI therapy and contribute our own institution's experience with a case of AHA after pembrolizumab therapy. Six cases of AHA, one case of aVWD, and one case of factor V inhibitor were identified in the literature. Inhibitors were successfully eradicated in five of the eight cases identified. We propose that a centralized registry, possibly through the Scientific and Standardization Subcommittee on Plasma Coagulation Inhibitors through the International Society on Thrombosis and Hemostasis (ISTH), be developed to record treatment and outcomes of this rare ICI complication in order to prognosticate risk and better understand optimal treatment strategies.

Drug-associated acquired hemophilia A: an analysis based on 185 cases from the WHO pharmacovigilance database

INTRODUCTION

Acquired hemophilia A (AHA) is a rare autoimmune hemorrhagic disease occurring in several underlying conditions. Drug-associated AHA (D-AHA) is poorly addressed nowadays.

AIM

This work aims to identify and characterize which drugs are associated with AHA using the WHO global database of reported potential effects of medicinal products (VigiBase).

METHODS

First, we realized a disproportionality analysis using the information component (IC) to identify D-AHA in VigiBase. IC compares observed- and expected-values in order to find associations between drugs and adverse drug reactions (ADRs) using disproportionate Bayesian reporting. IC₀₂₅ is the lower end of a 95% credibility interval for the IC. Then, we collected cases of drugs significantly associated with AHA from July 2004 to November 2021.

RESULTS

14 drugs with IC₀₂₅ > 0 were identified representing a total of 185 cases. D-AHA occurred more frequently in men (59%) than women (41%). The median (min-max) age at onset was 75 years (8-98). The median [Q1-Q3] time to onset of D-AHA from the start of the suspected drug was 30 days [9.5-73.75] and 10% of cases resulted in a fatality. The drugs associated with the highest IC₀₂₅ (IC₀₂₅ > 2) were Clopidogrel, Alemtuzumab, Omalizumab. This study retrieved for the first time three usually used drugs (3/14) that exhibit a significant pharmacovigilance signal for D-AHA.

CONCLUSION

This worldwide pharmaco-epidemiologic study updates the list of the drugs associated with AHA. The clinician should be aware of these possible severe ADR, which might require larger epidemiological and pathophysiologic studies.