AB0756 IMMUNE-MEDIATED BASIS FOR A PHASE 2A CLINICAL STUDY COMPARING RILZABRUTINIB VS GLUCOCORTICOIDS IN RITUXIMAB-REFRACTORY PATIENTS WITH IGG4-RELATED DISEASE

Background:

IgG4-related disease (IgG4-RD) is an immune-mediated disorder causing fibro-inflammatory lesions. Although the cause remains unknown, it may be driven by interactions between B lymphocytes and CD4+ cytotoxic and regulatory T cells and is characterized by an increase in short-lived plasmablasts, circulating antibodies, and macrophages. Standard therapy mainly includes glucocorticoids (GC), limited by toxicity with long-term use (> 6 mo), and to a lesser extent, immunosuppressives (eg, rituximab). Bruton tyrosine kinase (BTK) plays an important role in the activation of multiple immune effector cells such as B cells, mast cells, eosinophils, basophils, monocytes/macrophages, and neutrophils. Dysregulation of the activation of these immune cells results in autoimmune inflammation, tissue damage, and development of fibrosis. Rilzabrutinib is a highly selective oral BTK inhibitor that targets multiple pathways of innate and adaptive immunity (with direct effects on B-cell and FcR pathways) and has the potential to inhibit antigen presentation to autoreactive T cells.

Objectives:

To provide the biological rationale for rilzabrutinib in IgG4-RD.

Methods:

Rilzabrutinib has been evaluated in biochemical, in vitro studies, and in vivo models of inflammatory diseases. Additional support is provided by the phase 2 trial for oral rilzabrutinib in patients with pemphigus vulgaris and the phase 2 trial for oral rilzabrutinib in patients with immune thrombocytopenia (ITP).

Results:

Rilzabrutinib inhibited the activity of BTK and B-cell receptor in B cells (IC50 5-123 nM) and Fc gamma receptor in IgG/Fc gamma receptor-stimulated monocytes (IC50 56 nM) and blocked IgG- and IgM-mediated antibody production in enriched B cells when stimulated in T-cell dependent (anti-CD40+IL-21) and T-cell independent (TLR-9/CpG and TNP-LPS) pathways. The impact of rilzabrutinib on innate cell pathways was further confirmed by significant dose-dependent inhibition of macrophage and neutrophil-driven passive rat Arthus reaction (P < 0.01 vs vehicle) and antibody-induced murine ITP (P < 0.05 vs vehicle). In a 12-week phase 2 pemphigus vulgaris trial, 54% of patients achieved the primary endpoint, control of disease activity (CDA) on low-dose corticosteroids by week 4, and 73% achieved it by week 12. In the phase 2 trial of ITP patients (median 6 prior therapies), rilzabrutinib 400 mg bid showed rapid and sustained improvement in platelet counts and only grade 1/2-related adverse events1. In responders, platelet counts increased as early as day 8, potentially due to innate immune mechanisms. Collectively, results in both B and innate immune cells provide an initial basis for evaluating rilzabrutinib in IgG4-RD. The ongoing phase 2a study (NCT04520451) is investigating rilzabrutinib 400 mg bid (+tapered GC) vs GC control (3:1) for 12 weeks in IgG4-RD patients refractory to rituximab. The primary objective is to evaluate the safety and ability of rilzabrutinib to induce GC-free remission at week 12. Coupled with known preclinical/clinical findings, mechanistic analyses in this ongoing IgG4-RD study will profile B and other immune cell effects pre-/post-rilzabrutinib dosing to enhance the clinical understanding of rilzabrutinib in IgG4-RD.

Conclusion:

Studies of rilzabrutinib that show beneficial effects on both B-cell and innate cell pathways provide support for its therapeutic role in immune-mediated diseases and for targeting the underlying pathophysiological effects of IgG4-RD. Effective and safe therapies that rapidly induce and maintain clinical responses, while minimizing the need for continuous GC treatment, remain an unmet need for patients with IgG4-RD.

References:

[1]Kuter et al. Res Pract Thromb Haemost. 2020;4(suppl 1): PB1318.

Disclosure of Interests:

Li Long Employee of: Principia Biopharma, a Sanofi Company, Matthew Baker: None declared, Mollie Carruthers: None declared, Alireza Meysami: None declared, Robert Spiera Consultant of: research funding and personal fees for consulting from Chemocentryx, Formation Biologics, Roche-Genentech, and Sanofi, Grant/research support from: research funding fees from BMS, Boehringer Ingelheim, Corbus, GSK, and Inflarx; personal fees from AbbVie, CSL Behring, GSK, and Janssen, Mamatha Reddy Employee of: Principia Biopharma, a Sanofi Company, Marianne Kavanagh Employee of: Principia Biopharma, a Sanofi Company, Michelle Francesco Employee of: Principia Biopharma, a Sanofi Company, Claire Langrish Employee of: Principia Biopharma, a Sanofi Company, Ann Neale Employee of: Principia Biopharma, a Sanofi Company, Puneet Arora Employee of: Principia Biopharma, a Sanofi Company, John H. Stone Consultant of: research funding and personal fees for consulting from Principia and Sanofi

A survey on the practices and capabilities in the management of respiratory failure in South East England

Introduction

The variability of acute respiratory distress syndrome management may affect the referral practice to severe respiratory failure centres. We described the management of acute respiratory distress syndrome in our catchment area.

Methods

An electronic survey was administered to 42 intensive care units in South-East England.

Results

Response rate was 71.4%. High-flow nasal oxygen and non-invasive ventilation were used 'often' in moderate-acute respiratory distress syndrome by 46.7% and 60%. During invasive ventilation, 90% preferred pressure control, targeting tidal volumes of 6-8 ml/kg (53.3%) or 4-6 ml/kg (46.7%). Positive end-expiratory pressure was selected by positive end-expiratory pressure/inspiratory fraction of oxygen tables (50%) or decremental positive end-expiratory pressure trials (20%). Neuro-muscular blockers were widely used, although routinely by only 3.3%. High-frequency oscillatory ventilation (10%) and inhaled nitric oxide (13.3%) were rarely used. None used oesophageal manometry. Recruitment manoeuvres were used 'often' by 26.7%. Equipment (90%) and protocols (80%) for prone position were common, with sessions mostly lasting 12-18 h.

Conclusions

Although variable, practice well reflected the available evidence. Proning was widely practiced with good availability of educational resources and protocolised care.

International survey on the management of mechanical ventilation during ECMO in adults with severe respiratory failure

BACKGROUND

No consensus exists on the optimal settings of mechanical ventilation during veno-venous extracorporeal membrane oxygenation (ECMO). Our aim was to describe how mechanical ventilation and related interventions are managed by adult ECMO centres.

METHODS

A cross-sectional, multi-centre, international survey of 173 adult respiratory ECMO centres. The survey was generated through an iterative process and assessed for clarity, content and face validity.

RESULTS

One hundred thirty-three centres responded (76.8%). Pressure control was the most commonly used mechanical ventilation mode (64.4%). Although the median PEEP was 10 cmH2O, 22.6% set PEEP <10 cmH2O and 15.5% used 15-20 cmH2O. In 63% of centres PEEP was fixed and not titrated. Recruitment maneuvres, were never used in 34.1% of centres, or used daily in 13.2%. Centres reported using either a "lung rest" (45.7%), or an "open lung" strategy (44.2%). Only 24.8% used chest CT to guide mechanical ventilation. Adjunctive treatments were never or occasionally used. Only 10% of centres extubated patients on ECMO, mainly in more experienced centres. 71.3% of centres performed tracheostomy on ECMO, with large variability in timing (most frequent on days 6-10). Only 27.1% of ECMO centres had a protocol for mechanical ventilation on ECMO.

CONCLUSION

We found large variability in ventilatory practices during ECMO. The clinicians' training background and the centres' experience had no influence on the approach to ventilation. This survey shows that well conducted studies are necessary to determine the best practice of mechanical ventilation during ECMO and its impact on patient outcome.

Capabilities of a mobile extracorporeal membrane oxygenation service for severe respiratory failure delivered by intensive care specialists

We conducted a single-centre observational study of retrievals for severe respiratory failure over 12 months. Our intensivist-delivered retrieval service has mobile extracorporeal membrane oxygenation capabilities. Sixty patients were analysed: 34 (57%) were female and the mean (SD) age was 44.1 (13.6) years. The mean (SD) PaO2 /FI O2 ratio at referral was 10.2 (4.1) kPa and median (IQR [range]) Murray score was 3.25 (3.0-3.5 [1.5-4.0]). Forty-eight patients (80%) required veno-venous extracorporeal membrane oxygenation at the referring centre. There were no cannulation or extracorporeal membrane oxygenation-related complications. The median (IQR [range]) retrieval distance was 47.2 (14.9-77.0 [2.3-342.0]) miles. There were no major adverse events during retrieval. Thirty-seven patients (77%) who received extracorporeal membrane oxygenation survived to discharge from the intensive care unit and 36 patients (75%) were alive after six months. Senior intensivist-initiated and delivered mobile extracorporeal membrane oxygenation is safe and associated with a high incidence of survival.

Individualising Management of Severe Respiratory Failure and the Specialist Commissioned Severe Respiratory Failure Service for England

Despite the improvement in the survival rate in patients with acute respiratory distress syndrome, there is a cohort of patients with severe hypoxaemia and hypercapnia who offer a significant therapeutic challenge and may require some of the more contentious rescue therapies, including prone positioning, high-frequency oscillatory ventilation and extracorporeal support. It is essential to implement a protocolised pathway for diagnosis and individualised treatment for these patients. In 2011, the English National Specialist Commissioning Service established a number of severe respiratory centres for England including the provision of extracorporeal membrane oxygenation. Early referral is essential for the successful use of rescue therapy as the evidence indicates that the time of mechanical ventilation prior to rescue therapy is a key predictor of mortality. Guy's and St Thomas' NHS Foundation Trust has been commissioned as one of the severe respiratory failure services and we describe the process of assessment and management that we have instituted to manage patients with severe respiratory failure.

Severe respiratory illness caused by a novel coronavirus, in a patient transferred to the United Kingdom from the Middle East, September 2012

Coronaviruses have the potential to cause severe transmissible human disease, as demonstrated by the severe acute respiratory syndrome (SARS) outbreak of 2003. We describe here the clinical and virological features of a novel coronavirus infection causing severe respiratory illness in a patient transferred to London, United Kingdom, from the Gulf region of the Middle East.

The United Kingdom public health response to an imported laboratory confirmed case of a novel coronavirus in September 2012

On 22 September 2012, a novel coronavirus, very closely related to that from a fatal case in Saudi Arabia three months previously, was detected in a previously well adult transferred to intensive care in London from Qatar with severe respiratory illness. Strict respiratory isolation was instituted. Ten days after last exposure, none of 64 close contacts had developed severe disease, with 13 of 64 reporting mild respiratory symptoms. The novel coronavirus was not detected in 10 of 10 symptomatic contacts tested.

The United Kingdom public health response to an imported laboratory confirmed case of a novel coronavirus in September 2012

On 22 September 2012, a novel coronavirus, very closely related to that from a fatal case in Saudi Arabia three months previously, was detected in a previously well adult transferred to intensive care in London from Qatar with severe respiratory illness. Strict respiratory isolation was instituted. Ten days after last exposure, none of 64 close contacts had developed severe disease, with 13 of 64 reporting mild respiratory symptoms. The novel coronavirus was not detected in 10 of 10 symptomatic contacts tested.

Severe respiratory illness caused by a novel coronavirus, in a patient transferred to the United Kingdom from the Middle East, September 2012

Coronaviruses have the potential to cause severe transmissible human disease, as demonstrated by the severe acute respiratory syndrome (SARS) outbreak of 2003. We describe here the clinical and virological features of a novel coronavirus infection causing severe respiratory illness in a patient transferred to London, United Kingdom, from the Gulf region of the Middle East.

Cerebral infarction following thrombolysis for massive pulmonary embolism

A 29-year-old male developed a fatal stroke 6 h after successful thrombolysis for massive pulmonary embolism. Autopsy showed thrombus protruding through a patent foramen ovale (PFO). A strand of thrombus extended from the aortic arch into the left common carotid artery. The brain showed extensive infarction of the left fronto-parietal area. Thrombolysis caused initial disintegration of the embolism. It is likely that thrombolysis caused fragments of clot to later break lose and embolise into the cerebral circulation. We discuss the need for risk stratification in patients who present with massive pulmonary embolism and PFO.