Interruption of BTK inhibitor improves response to SARS-CoV-2 booster vaccination in patients with CLL

A 3-week pause versus continued Bruton tyrosine kinase inhibitor use during COVID-19 vaccination in individuals with chronic lymphocytic leukaemia (IMPROVE trial): a randomised, open-label, superiority trial

BACKGROUND

Chronic lymphocytic leukaemia is the commonest leukaemia and is associated with profound immunosuppression. Bruton tyrosine kinase inhibitors (BTKi) have revolutionised chronic lymphocytic leukaemia management; however, therapy impairs vaccine-induced immunity. We evaluated whether a 3-week pause of BTKi treatment improved spike protein receptor binding domain (RBD) immunity to SARS-CoV-2 booster vaccination while maintaining disease control.

METHODS

We performed an open-label, two-arm, parallel-group, randomised trial in secondary-care haematology clinics in 11 UK hospitals. Participants aged 18 years or older, diagnosed with chronic lymphocytic leukaemia, and currently taking BTKi therapy (frontline or relapsed setting) for at least 12 months were eligible. Participants were randomly allocated (1:1, by a centralised computer randomisation program, stratified by BTKi therapy line) to pause BTKi for 3 weeks, starting 6 days before their SARS-CoV-2 vaccination booster date, or to continue therapy as usual. Neither participants nor clinical staff were blinded but laboratory staff were. Intramuscular injection of either original BA.1 or original BA.4/5 bivalent mRNA vaccine (50 μg mRNA-1273 or 30 μg BNT162b2), or 5 μg protein-based Vidprevtyn Beta (Sanofi Pasteur, Lyon, France) were received according to the national vaccination programme schedule. The primary outcome measure was anti-spike-RBD-specific antibody titre 3 weeks after vaccination and analysis performed by intention to treat (as randomly allocated, irrespective of compliance) following trial completion. This trial is registered with ISRCTN, 14197181, and has been completed.

FINDINGS

Between Oct 10, 2022, and June 8, 2023, 99 individuals (71 [72%] male and 28 [28%] female, with 89 [90%] of White ethnicity) were randomly allocated to groups pausing (n=50 [51%]) or continuing (n=49 [49%]) their BTKi therapy, and followed up for 12 weeks. At 3 weeks after vaccination, the geometric mean anti-spike-RBD-specific antibody titre was 218·8 U/mL (SD 122·9) in the continue group and 153·4 U/mL (103·2) in the pause group, with geometric mean ratio 1·104 (95% CI 0·565-2·158, p=0·77) using a mixed-effects model. The only serious adverse event during the 12-week follow-up was the death of one participant in the pause group due to COVID-19 infection 2 months after randomisation.

INTERPRETATION

Although the study was slightly underpowered, the results suggest that pausing BTKi around the time of vaccination is not beneficial for immunity and should not be recommended in clinical practice.

FUNDING

National Institute for Health and Care Research.

Chronic Lymphocytic Leukemia Care and Beyond: Navigating the Needs of Long-Term Survivors

Chronic lymphocytic leukemia (CLL) treatment has undergone a significant evolution with a shift from historical chemotherapeutic regimens to targeted therapies such as Bruton tyrosine kinase (BTK) and BCL-2 inhibitors. These advancements have been associated with a notable improvement in survival rates with a transformation of CLL into a chronic and manageable condition for most persons with this disease. However, as a consequence of improved outcomes, long-term CLL survivors now face emergent challenges which include a risk of infections, cardiovascular complications, and secondary malignancies. In this changed scenario, holistic models of care are essential to address emergent health risks. Such models of care for CLL patients require a multidisciplinary approach that integrates CLL treatment with the proactive management of frailty, comorbidities, and psychosocial well-being to enhance both survival and quality of life (QoL). CLL predominantly affects older persons, many of whom present with concurrent frailty and comorbidities that may complicate CLL treatment and impact QoL. Comprehensive geriatric assessments (GA) may play a critical role in the identification of persons at a heightened risk of treatment-related toxicity and may help guide rational therapy selection, particularly in very frail persons. In addition to the assessment of hematological responses, the prospective assessment of patient-reported outcomes (PROs) and frailty metrics may offer a more nuanced understanding of the global treatment benefits. A survivorship-focused care model is crucial to address the multifaceted needs of CLL patients with the extension of patient care into the broader domain of long-term health maintenance with associated improvements in QoL.

Bruton's tyrosine kinase inhibition for the treatment of allergic disorders

IgE signaling through its high-affinity receptor FcεRI is central to the pathogenesis of numerous allergic disorders. Oral inhibitors of Bruton's tyrosine kinase (BTKis), which are currently Food and Drug Administration-approved for treating B cell malignancies, broadly inhibit the FcεRI pathway in human mast cells and basophils, and therefore may be effective allergen-independent therapies for a variety of allergic diseases. The application of these drugs to the allergy space was previously limited by the low kinase selectivity and subsequent toxicities of early-generation compounds. Fortunately, next-generation, highly selective BTKis in clinical development appear to have more favorable risk-benefit profiles, and their likelihood of being Food and Drug Administration-approved for an allergy indication is increasing. Recent clinical trials have indicated the remarkable and rapid efficacy of the second-generation BTKi acalabrutinib in preventing clinical reactivity to peanut ingestion in adults with peanut allergy. In addition, next-generation BTKis including remibrutinib effectively reduce disease activity in patients with antihistamine-refractory chronic spontaneous urticaria. Finally, several BTKis are currently under investigation in early clinical trials for atopic dermatitis and asthma. In this review, we summarize recent data supporting the use of these drugs as novel therapies in food allergy, anaphylaxis, urticaria, and other allergic disorders. We also discuss safety data derived from trials using both short-term and chronic dosing of BTKis.