Efficient Distribution of a Novel Zirconium-89 Labeled Anti-cd20 Antibody Following Subcutaneous and Intravenous Administration in Control and Experimental Autoimmune Encephalomyelitis-Variant Mice

Dental Adverse Effects of Anti-CD20 Therapies

INTRODUCTION

Over the past few years, anti-CD20 therapies like rituximab, ocrelizumab or ofatumumab have seen an increase in interest in the treatment of neurological autoimmune disorders such as multiple sclerosis (MS), neuromyelitis optica spectrum disorders (NMOSD), or resistant forms of generalized myasthenia gravis (MG). They are generally well-tolerated, but recent reports have highlighted severe dental disorders in patients undergoing anti-CD20 therapies. The aim was to describe a series of cases and to compare with the available scientific literature.

METHODS

We reviewed 6 patient cases with dental disorders during anti-CD20 therapy that were reported to the pharmacovigilance center. A disproportionality analysis was also conducted on Vigibase® for each anti-CD20 and each adverse effect described in the cases.

RESULTS

Six cases of dental and gingival conditions in relatively young patients were reported (median age: 40.5 years old [min: 34; max: 79]). Oral conditions were developed in four patients with MS treated with ocrelizumab and in two patients receiving rituximab (one patient with MG and one with NMOSD). The onset of oral conditions ranged from 10 days to 2 years after treatment initiation. Notably, all patients treated with ocrelizumab experienced gingival recession. Various dental pathologies were observed, including tooth loss, dental pain, caries, brittle teeth, dental fractures, dental abscesses, and periodontitis. Analysis of Vigibase® revealed 284 worldwide cases of dental and gingival conditions under ocrelizumab, 386 cases under rituximab, and 80 under ofatumumab. Significant associations were found between these therapies and dental pathologies, particularly tooth abscesses and infections.

CONCLUSION

To our knowledge, this is the first case series reporting dental conditions developed in patients long-term treated with anti-CD20 treatments. This issue, literature data, and Vigilyze® analysis might be considered a safety signal that necessitates being confirmed with more robust data, such as a retrospective study with a control group. Meanwhile, proactive measures are essential like frequent dental checkups and dental hygienic measures to prevent oral health problems associated with anti-CD20 therapies.

Different lymphocyte counts of multiple sclerosis patients treated with ofatumumab and ocrelizumab: A retrospective observational study

Introduction

Patients with Multiple Sclerosis (pwMS) treated with anti-CD20 (cluster of differentiation) monoclonal antibodies (mAbs) such as ocrelizumab (OCR) and ofatumumab (OFA) show a reduction mainly of B-lymphocytes, but also other lymphocyte subsets can be affected by these treatments. There is limited data on differences between lymphocyte subset counts of pwMS after treatment initiation with OCR or OFA.

Objective

To compare lymphocyte subset counts after treatment initiation in pwMS treated with OCR and OFA.

Methods

We analyzed 22 pwMS initiated on OFA and 56 sex-, age- and MS course matched pwMS initiated on OCR from 2 prospectively collected observational MS databases (Bern [n: OFA 14, OCR 44] and Vienna [n: OFA 8, OCR 12]) statistically comparing lymphocyte subset counts (Mann Whitney Test).

Results

We found that pwMS treated with OCR showed a stronger reduction of CD20 B-lymphocytes (P = .001), and a trend towards lower counts of CD8+ T cells (P = .056) compared to pwMS treated with OFA, whereas reduction of total lymphocyte, CD4+ lymphocyte and NK cell count was equally distributed between both treatments.

Conclusion

Different effects on lymphocyte subpopulations appear to be present in pwMS after treatment initiation with different anti-CD20 mAbs. Further studies are needed to determine potential effects on anti-CD20 treatment efficacy as well as treatment associated risks such as failed vaccinations and infections.

Key characteristics of anti-CD20 monoclonal antibodies and clinical implications for multiple sclerosis treatment

The recent success of anti-CD20 monoclonal antibody therapies in the treatment of multiple sclerosis (MS) has highlighted the role of B cells in the pathogenesis of MS. In people with MS, the inflammatory characteristics of B-cell activity are elevated, leading to increased pro-inflammatory cytokine release, diminished anti-inflammatory cytokine production and an accumulation of pathogenic B cells in the cerebrospinal fluid. Rituximab, ocrelizumab, ofatumumab, ublituximab and BCD-132 are anti-CD20 therapies that are either undergoing clinical development, or have been approved, for the treatment of MS. Despite CD20 being a common target for these therapies, differences have been reported in their mechanistic, pharmacological and clinical characteristics, which may have substantial clinical implications. This narrative review explores key characteristics of these therapies. By using clinical trial data and real-world evidence, we discuss their mechanisms of action, routes of administration, efficacy (in relation to B-cell kinetics), safety, tolerability and convenience of use. Clinicians, alongside patients and their families, should consider the aspects discussed in this review as part of shared decision-making discussions to improve outcomes and health-related quality of life for people living with MS.

Preclinical Pharmacokinetics and Biodistribution of LR004, a Novel Antiepidermal Growth Factor Receptor Monoclonal Antibody

LR004 is a novel chimeric (human/mouse) monoclonal antibody developed for the treatment of advanced colorectal carcinoma with detectable epidermal growth factor receptor (EGFR) expression. We aimed to investigate the preclinical pharmacokinetics (PK) and in vivo biodistribution of LR004. The PK profiles of LR004 were initially established in rhesus monkeys. Subsequently, 125I radionuclide-labeled LR004 was developed and the biodistribution, autoradiography, and NanoSPECT/CT of 125I-LR004 in xenograft mice bearing A431 tumors were examined. The PK data revealed a prolonged half-life and nonlinear PK characteristics of LR004 within the dose range of 6-54 mg/kg. The radiochemical purity of 125I-LR004 was approximately 98.54%, and iodination of LR004 did not affect its specific binding activity to the EGFR antigen. In a classical biodistribution study, 125I-LR004 exhibited higher uptake in highly perfused organs than in poorly perfused organs. Prolonged retention properties of 125I-LR004 in tumors were observed at 4 and 10 days. Autoradiography and NanoSPECT/CT confirmed the sustained retention of 125I-LR004 at the tumor site in xenograft mice. These findings demonstrated the adequate tumor targeting capabilities of 125I-LR004 in EGFR-positive tumors, which may improve dosing strategies and future drug development.

New Long-Acting [89Zr]Zr-DFO GLP-1 PET Tracers with Increased Molar Activity and Reduced Kidney Accumulation

Positron emission tomography (PET) imaging is used in drug development to noninvasively measure biodistribution and receptor occupancy. Ideally, PET tracers retain target binding and biodistribution properties of the investigated drug. Previously, we developed a zirconium-89 PET tracer based on a long-circulating glucagon-like peptide 1 receptor agonist (GLP-1RA) using desferrioxamine (DFO) as a chelator. Here, we aimed to develop an improved zirconium-89-labeled GLP-1RA with increased molar activity to increase the uptake in low receptor density tissues, such as brain. Furthermore, we aimed at reducing tracer accumulation in the kidneys. Introducing up to four additional Zr-DFOs resulted in higher molar activity and stability, while retaining potency. Branched placement of DFOs was especially beneficial. Tracers with either two or four DFOs had similar biodistribution as the tracer with one DFO in vivo, albeit increased kidney and liver uptake. Reduced kidney accumulation was achieved by introducing an enzymatically cleavable Met-Val-Lys (MVK) linker motif between the chelator and the peptide.

Assessment of the treating physicians' first-hand experience with handling and satisfaction of ofatumumab therapy: findings from the PERITIA survey conducted in Europe

BACKGROUND

Real-world evidence on experience and satisfaction of ofatumumab as a treatment option for relapsing multiple sclerosis (RMS) is limited.

OBJECTIVE

To present cumulative responses from a questionnaire related to first-hand experience of treating physicians on handling and convenience of ofatumumab therapy along with concerns related to COVID-19.

METHODS

PERITIA was a multicentre survey conducted to collect responses from the ASCLEPIOS I/II trial investigators from Europe via an online questionnaire.

RESULTS

Forty-six physicians (Germany, n = 14; Spain, n = 12; Portugal, n = 10; Italy, n = 10) completed the survey. Overall, 43% of the physicians considered the benefit-risk ratio of ofatumumab as very good. Over 93% were in favour of ofatumumab self-administration at home and the majority (83%) believed it to be completely true that self-administration of ofatumumab eases the burden for patients in terms of time. All investigators would like to potentially use anti-CD20 therapy as a long-term strategy. Even during the COVID-19 pandemic, physicians were in favour of a self-administration of MS therapy at home over other anti-CD20 therapy infusions.

CONCLUSION

European neurologists who were part of this survey considered the benefit-risk-ratio of ofatumumab as favourable and the monthly self-administered subcutaneous injections offering convenience for patients in the clinical practice.

ImmunoPET Directed to the Brain: A New Tool for Preclinical and Clinical Neuroscience

Immuno-positron emission tomography (immunoPET) is a non-invasive in vivo imaging method based on tracking and quantifying radiolabeled monoclonal antibodies (mAbs) and other related molecules, such as antibody fragments, nanobodies, or affibodies. However, the success of immunoPET in neuroimaging is limited because intact antibodies cannot penetrate the blood-brain barrier (BBB). In neuro-oncology, immunoPET has been successfully applied to brain tumors because of the compromised BBB. Different strategies, such as changes in antibody properties, use of physiological mechanisms in the BBB, or induced changes to BBB permeability, have been developed to deliver antibodies to the brain. These approaches have recently started to be applied in preclinical central nervous system PET studies. Therefore, immunoPET could be a new approach for developing more specific PET probes directed to different brain targets.