The consequences of COVID-19 pandemic on patients with monoclonal gammopathy-associated systemic capillary leak syndrome (Clarkson disease)

The Role of the European Medicines Agency in the Safety Monitoring of COVID-19 Vaccines and Future Directions in Enhancing Vaccine Safety Globally

The European Union (EU) regulatory network was at the forefront of the safety monitoring of COVID-19 vaccines during the pandemic. An unprecedented number of case reports of suspected adverse reactions after vaccination called for huge efforts for the assessment of this safety information, to ensure that any possible risks were detected and managed as early as possible, while ruling out coincidental but temporally related adverse health outcomes. We describe the role of the European Medicines Agency alongside the EU regulatory network in the safety monitoring of the COVID-19 vaccines, and provide an insight into challenges, particularities and outcomes of the scientific assessment and regulatory decisions in the complex, dynamic international environment of the pandemic. We discuss the flexible procedural tools that were used to ensure an expedited scientific assessment of safety issues, and subsequent updates of the product information (i.e., labelling) when available evidence (e.g., spontaneous reports, findings from observational studies and/or scientific literature) suggested that causal association is at least a reasonable possibility. The safety monitoring was accompanied by enhanced transparency measures, proactive communication, and easy access to information, which played a key role in public reassurance. The pandemic has been a powerful booster for worldwide collaboration, exchange of information and work-sharing. The safety monitoring of COVID-19 vaccines continues, and the lessons learned will be applied in future safety reviews, as well as future health emergencies.

Two cases of systemic capillary leak syndrome associated with COVID-19 in Japan

Systemic Capillary Leak Syndrome (SCLS) is a rare disease that causes severe distributive shock provoked by infection or vaccination. SCLS is clinically diagnosed by a triad of distributive shock, paradoxical hemoconcentration, and hypoalbuminemia. SCLS associated with coronavirus disease (COVID-19) in adults has not been reported yet in Japan. Case 1: A 61-year-old woman with fever, sore throat, headache, and muscle pain was admitted to our emergency department with suspected COVID-19. She had been diagnosed with SCLS 3 years earlier. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigen and polymerase chain reaction (PCR) tests were negative at admission. She went into shock in the emergency department and was treated for septic shock. The following day, the SARS-CoV-2 PCR test was positive. She did not respond to fluid resuscitation and catecholamine and finally died. Case 2: A 58-year-old man was admitted to our hospital for de-saturation due to COVID-19. He got into shock on day 3. SCLS was suspected, and 5 g of intravenous immunoglobulin and 5% albumin were administered for sepsis treatment. He responded to the aggressive fluid therapy within 48 h and was finally discharged. COVID-19 can trigger SCLS, and early recognition of SCLS is crucial for survival. Primary care physicians should consider SCLS when they observe distributive shock and paradoxical hemoconcentration deviations from the natural course of COVID-19.

A ligand-independent Tie2-activating antibody reduces vascular leakage in models of Clarkson disease

Vascular dysfunction resulting from endothelial hyperpermeability is a common and important feature of critical illness due to sepsis, trauma, and other conditions associated with acute systemic inflammation. Clarkson disease [monoclonal gammopathy-associated idiopathic systemic capillary leak syndrome (ISCLS)] is a rare, orphan disorder marked by spontaneous and recurrent episodes of hypotensive shock and peripheral edema due to widespread vascular leakage in peripheral tissues. Mortality from acute flares approaches 30% due to lack of effective therapies. We evaluated a monoclonal antibody (4E2) specific for the endothelial receptor tyrosine kinase Tie2 in ISCLS models. 4E2 activated Tie2 in ISCLS patient-derived endothelial cells and reduced baseline and proinflammatory mediator-induced barrier dysfunction. 4E2 also reduced mortality and/or vascular leakage associated with systemic histamine challenge or influenza infection in the SJL/J mouse model of ISCLS. These findings support a critical role for Tie2 dysregulation in ISCLS and highlight a viable therapeutic approach to this catastrophic disorder.

Intravenous Immunoglobulins Tapering and Withdrawal in Systemic Capillary Leak Syndrome (Clarkson Disease)

BACKGROUND

The systemic capillary leak syndrome (SCLS), also known as Clarkson disease, is a very rare condition characterized by recurrent life-threatening episodes of vascular hyperpermeability in the presence of a monoclonal gammopathy. Extended intravenous immunoglobulin (IVIG) treatment is associated with fewer recurrences and improved survival, but the optimal treatment dosage and duration remain unknown.

OBJECTIVE

We aim to evaluate the safety of IVIG tapering and withdrawal in patients with SCLS.

METHODS

We conducted a retrospective multicenter study including all adult patients with monoclonal gammopathy-associated SCLS from the EurêClark registry who received at least 1 course of IVIG. The primary end point was overall survival according to IVIG withdrawal.

RESULTS

Fifty-nine patients of mean ± SD age 51 ± 13 years were included. Overall cumulative probabilities of 2-, 5-, 10- and 15-year survival were 100%, 85%, 72%, 44%, respectively. The IVIG was withdrawn at least once in 18 patients (31%; W+ group) and never in 41 patients (69%; W- group). Cumulative probabilities of 10-year survival in W+ versus W- groups were 50% and 83% (log rank test, P = .02), respectively. Relapse rate and the median number of relapses in the W+ versus the W- groups were 72% versus 58% (P = 0.3) and 2.5 (0.3-4) versus 1 (0-2) (P = .03), respectively. The IVIG tapering was not statistically associated with increased person-year incidence of attacks using a mixed linear model.

CONCLUSIONS

The IVIG withdrawal was associated with increased mortality and higher rate of recurrence in SCLS patients. The IVIG tapering might be cautiously considered in stable SCLS patients.

Management of Acute Episodes of Clarkson Disease (Monoclonal Gammopathy-Associated Systemic Capillary Leak Syndrome) With Intravenous Immunoglobulins

Monoclonal gammopathy-associated idiopathic systemic capillary leak syndrome (ISCLS, Clarkson disease) is a rare disorder defined by transient but recurrent bouts of hypotensive shock and anasarca resulting from plasma extravasation. Although prophylactic treatment with high-dose intravenous immunoglobulins (IVIG, 1–2 g/kg/mo) prevents most disease flares, its utility for acute episodes of ISCLS is unclear. Here, we report the results of a retrospective study of subjects with acute ISCLS treated at or near the onset of symptoms with IVIG. We found that administration of IVIG with minimal additional intravenous fluids was safe and associated with rapid clinical improvement. IVIG given close to the onset of ISCLS-related symptoms is associated with a favorable outcome.