Balancing Potential Benefits and Risks of Bruton Tyrosine Kinase Inhibitor Therapies in Multiple Sclerosis During the COVID-19 Pandemic

The Chimera of TPGS and Nanoscale Lipid Carriers as Lymphatic Drug Delivery Vehicles to Fight Metastatic Cancers

The lymphatic system (LS) plays a crucial role in fluid balance, transportation of macromolecules, and immune response. Moreover, LS is a channel for microbial invasion and cancer metastasis. Particularly, solid tumors, including lung, breast, melanoma, and prostate cancers, are metastasized across highways of LS. Subsequently, the fabrication of chimeric lymphatic drug delivery systems (LDDS) is a promising strategy to fight cancer metastasis and control microbial pandemics. In this regard, LDDS, in terms of PEG-nanoscaled lipid carriers, elicited a revolution during the COVID-19 pandemic as cargoes for mRNA vaccines. The drug delivered by the lymphatic pathway escapes first-pass metabolism and enhances the drug's bioavailability. Ample approaches, including synthesis of prodrugs, trigging of chylomicron biosynthesis, and fabrication of nanocarriers, facilitate lymphatic drug delivery. Specifically, nanoscales lipid cargoes have the propensity to lymphatic trafficking. Interestingly, TPGSengineered nanoscale lipid cargoes enhance lymphatic trafficking, increase tissue permeation, and, specifically, uptake. Moreover, they overcome biological barriers, control biodistribution, and enhance organelles localization. Most anticancer agents are non-specific, have low bioavailability, and induced drug resistance. Therefore, TPGS-engineered nanoscale lipid chimeras improve the therapeutic impact of anticancer agents. This review highlights lymphatic cancer metastasis, nanoscales lipid cargoes as LDDS, and their influence on lymphatic trafficking, besides the methods of LDD studies.

Mitigating Serious Adverse Events in Gene Therapy with AAV Vectors: Vector Dose and Immunosuppression

Gene transfer with high doses of adeno-associated viral (AAV) vectors has resulted in serious adverse events and even death of the recipients. Toxicity could most likely be circumvented by repeated injections of lower and less toxic doses of vectors. This has not been pursued as AAV vectors induce potent neutralizing antibodies, which prevent cell transduction upon reinjection of the same vector. This review discusses different types of immune responses against AAV vectors and how they offer targets for the elimination or inhibition of vector-specific neutralizing antibodies. Such antibodies can be circumvented by using different virus serotypes for sequential injections, they can be removed by plasmapheresis, or they can be destroyed by enzymatic degradation. Antibody producing cells can be eliminated by proteasome inhibitors. Drugs that inhibit T-cell responses, B-cell signaling, or presentation of the vector's antigens to B cells can prevent or reduce induction of AAV-specific antibodies. Combinations of different approaches and drugs are likely needed to suppress or eliminate neutralizing antibodies, which would then allow for repeated dosing. Alternatively, novel AAV vectors with higher transduction efficacy are being developed and may allow for a dose reduction, although it remains unknown if this will completely address the problem of high-dose adverse events.

Targeting B Cells and Microglia in Multiple Sclerosis With Bruton Tyrosine Kinase Inhibitors: A Review

Importance

Currently, disease-modifying therapies for multiple sclerosis (MS) use 4 mechanisms of action: immune modulation, suppressing immune cell proliferation, inhibiting immune cell migration, or cellular depletion. Over the last decades, the repertoire substantially increased because of the conceptual progress that not only T cells but also B cells play an important pathogenic role in MS, fostered by the empirical success of B cell-depleting antibodies against the surface molecule CD20. Notwithstanding this advance, a continuous absence of B cells may harbor safety risks, such as a decline in the endogenous production of immunoglobulins. Accordingly, novel B cell-directed MS therapies are in development, such as inhibitors targeting Bruton tyrosine kinase (BTK).

Observations

BTK is centrally involved in the B cell receptor-mediated activation of B cells, one key requirement in the development of autoreactive B cells, but also in the activation of myeloid cells, such as macrophages and microglia. Various compounds in development differ in their binding mode, selectivity and specificity, relative inhibitory concentration, and potential to enter the central nervous system. The latter may be important in assessing whether BTK inhibition is a promising strategy to control inflammatory circuits within the brain, the key process that is assumed to drive MS progression. Accordingly, clinical trials using BTK inhibitors are currently conducted in patients with relapsing-remitting MS as well as progressive MS, so far generating encouraging data regarding efficacy and safety.

Conclusions and Relevance

While the novel approach of targeting BTK is highly promising, several questions remain unanswered, such as the long-term effects of using BTK inhibitors in the treatment of inflammatory CNS disease. Potential changes in circulating antibody levels should be evaluated and compared with B cell depletion. Also important is the potential of BTK inhibitors to enter the CNS, which depends on the given compound. Remaining questions involve where BTK inhibitors fit in the landscape of MS therapeutics. A comparative analysis of their distinct properties is necessary to identify which inhibitors may be used in relapsing vs progressive forms of MS as well as to clarify which agent may be most suitable for sequential use after anti-CD20 treatment.

The late onset of emotional distress in people with progressive multiple sclerosis during the Covid-19 pandemic: longitudinal findings from the CogEx study

OBJECTIVE

An earlier follow-up study from the CogEx rehabilitation trial showed little change in symptoms of depression, anxiety and psychological distress during the first COVID-19 lockdown compared to pre-pandemic measurements. Here, we provide a second follow-up set of behavioral data on the CogEx sample.

METHODS

This was an ancillary, longitudinal follow-up study in CogEx, a randomized controlled trial of exercise and cognitive rehabilitation in people with progressive MS involving 11 centres in North America and Europe. Only individuals impaired on the Symbol Digit Modalities Test (SDMT) were included. Participants repeated the COVID Impact survey administered approximately a year later and completed self-report measures of depression, anxiety and MS symptoms that had been obtained at the trial baseline and during the first COVID Impact survey. Participants who completed the second COVID Impact follow-up were included. To identify predictors of the participants' ratings of their mental and physical well-being, step-wise linear regression was conducted.

RESULTS

Of the 131 participants who completed the first COVID impact survey, 74 participants completed the second follow-up survey (mean age 52 (SD = 6.4) years, 62.2% female, mean disease duration 16.4 (SD = 9.0) years, median EDSS 6.0). Pandemic restrictions prevented data collection from sites in Denmark and England (n = 57). The average time between measurements was 11.4 (SD = 5.56) months. There were no significant differences in age, sex, EDSS, disease course and duration between those who participated in the current follow-up study (n = 74) and the group that could not (n = 57). One participant had COVID in the time between assessments. Participants now took a more negative view of their mental/psychological well-being (p = 0.0001), physical well-being (p = 0.0009) and disease course (p = 0.005) compared to their last assessment. Depression scores increased on the HADS-depression scale (p = 0.01) and now exceeded the clinically significant threshold of ≥ 8.0 for the first time. Anxiety scores on the HADS remained unchanged. Poorer mental well-being was predicted by HADS depression scores (p = 0.012) and a secondary-progressive disease course (p = 0.0004).

CONCLUSIONS

A longer follow-up period revealed the later onset of clinically significant depressive symptoms on the HADS and a decline in self-perceptions of mental and physical well-being associated with the COVID-19 pandemic relative to the first follow-up data point.

TRIAL REGISTRATION

The trial was registered on September 20th 2018 at www.

CLINICALTRIALS

gov having identifier NCT03679468. Registration was performed before recruitment was initiated.

Bruton's Kinase Inhibitors for the Treatment of Immunological Diseases: Current Status and Perspectives

The use of Bruton’s tyrosine kinase (BTK) inhibitors has changed the management of patients with B-cell lymphoid malignancies. BTK is an important molecule that interconnects B-cell antigen receptor (BCR) signaling. BTK inhibitors (BTKis) are classified into three categories, namely covalent irreversible inhibitors, covalent reversible inhibitors, and non-covalent reversible inhibitors. Ibrutinib is the first covalent, irreversible BTK inhibitor approved in 2013 as a breakthrough therapy for chronic lymphocytic leukemia patients. Subsequently, two other covalent, irreversible, second-generation BTKis, acalabrutinib and zanubrutinib, have been developed for lymphoid malignancies to reduce the ibrutinib-mediated adverse effects. More recently, irreversible and reversible BTKis have been under development for immune-mediated diseases, including autoimmune hemolytic anemia, immune thrombocytopenia, multiple sclerosis, pemphigus vulgaris, atopic dermatitis, rheumatoid arthritis, systemic lupus erythematosus, Sjögren’s disease, and chronic spontaneous urticaria, among others. This review article summarizes the preclinical and clinical evidence supporting the role of BTKis in various autoimmune, allergic, and inflammatory conditions.

Impact of immunotherapies on COVID-19 outcomes in multiple sclerosis patients

INTRODUCTION

SARS-CoV-2 pandemic has led the scientific community to maximize efforts to prevent infections and disease severity in patients with multiple sclerosis (pwMS). We analyze the impact of immunotherapies on COVID-19 outcomes in pwMS, providing our interpretation of data.

AREAS COVERED

Infections, hospitalizations, intensive care unit admissions and death rates in COVID-19 pwMS are comparable to general population. Severity of disability, MS clinical phenotype, age and comorbidities, along with the use of intravenous methylprednisolone and anti-CD20 treatments, are risk factors for COVID-19 severity. Disease modifying treatments (DMTs) can be safely started and continued during the pandemic. Benefit-risk evaluation is mandatory when managing second-line therapies, to balance risk of worse COVID-19 outcomes and MS reactivation. COVID-19 vaccination is safe in MS and its efficacy could be reduced in fingolimod and ocrelizumab-treated patients.

EXPERT OPINION

Rate of (re)-infection and outcomes with SARS-CoV-2 variants in pwMS and antiviral properties of DMTs need to be further explored. Data on COVID-19 in pregnant MS women, children and elderly pwMS are limited. Evidence on long-term effects of infection is needed. Impact of emerging DMTs on COVID-19 should be investigated. More data and longer follow-up are needed to characterize long-term efficacy and safety profile of vaccinations in pwMS.

Bruton's Tyrosine Kinase Inhibitors in Multiple Sclerosis: Pioneering the Path Towards Treatment of Progression?

In multiple sclerosis (MS) persisting disability can derive from acute relapses or, alternatively, from slow and steady deterioration, termed chronic progression. Emerging data suggest that the latter process occurs largely independent from relapse activity or development of new central nervous system (CNS) inflammatory lesions. Pathophysiologically, acute relapses develop as a consequence of de novo CNS infiltration of immune cells, while MS progression appears to be driven by a CNS-trapped inflammatory circuit between CNS-established hematopoietic cells as well as CNS-resident cells, such as microglia, astrocytes, and oligodendrocytes. Within the last decades, powerful therapies have been developed to control relapse activity in MS. All of these agents were primarily designed to systemically target the peripheral immune system and/or to prevent CNS infiltration of immune cells. Based on the above described dichotomy of MS pathophysiology, it is understandable that these agents only exert minor effects on progression and that novel targets within the CNS have to be utilized to control MS progression independent of relapse activity. In this regard, one promising strategy may be the inhibition of the enzyme Bruton's tyrosine kinase (BTK), which is centrally involved in the activation of B cells as well as myeloid cells, such as macrophages and microglia. In this review, we discuss where and to what extent BTK is involved in the immunological and molecular cascades driving MS progression. We furthermore summarize all mechanistic, preclinical, and clinical data on the various BTK inhibitors (evobrutinib, tolebrutinib, fenebrutinib, remibrutinib, orelabrutinib, BIIB091) that are currently in development for treatment of MS, with a particular focus on the potential ability of either drug to control MS progression.

The impact of the COVID-19 pandemic on an international rehabilitation study in MS: the CogEx experience

Pandemic restrictions have led to changes in therapy plans and disrupted rehabilitation services for people with multiple sclerosis. CogEx is an international, multicentre MS dual-intervention (cognitive rehabilitation, aerobic exercise) randomized, controlled rehabilitation trial confined to people with progressive disease. The primary outcome is cognition (processing speed).There are 11 treatment sites in six countries with participants required to make 27 site visits over 12 weeks. Collectively, the large, in-person demands of the trial, and the varying international policies for the containment of COVID-19, might disproportionately impact the administration of CogEx. During the first lockdown, all centres closed on average for 82.9 (SD = 24.3) days. One site was required to lockdown on two further occasions. One site remained closed for 16 months. Ten staff (19.2%) were required to quarantine and eight staff (15.4%) tested positive for COVID. 10 of 264 (3.8%) participants acquired COVID-19. All survived. The mean duration of enrollment delay has been [236.7 (SD = 214.5) days]. Restarting participants whose interventions were interrupted by the pandemic meant recalculating the intervention prescriptions for these individuals. While the impact of the pandemic on CogEx has been considerable, all study sites are again open. Participants and staff have shown considerable flexibility and resilience in keeping a complex, international endeavour running. The future in general remains uncertain in the midst of a pandemic, but there is cautious optimism the study will be completed with sufficient sample size to robustly evaluate our hypothesis and provide meaningful results to the MS community on the impact of these interventions on people with progressive MS.Trial registration: The trial was registered on September 20th 2018 at www.clinicaltrials.gov having identifier NCT03679468. Registration was performed before recruitment was initiated.