Safety experience with continued exposure to ofatumumab in patients with relapsing forms of multiple sclerosis for up to 3.5 years.

BACKGROUND: Ofatumumab is approved for the treatment of relapsing multiple sclerosis (RMS). Ongoing safety reporting is crucial to understand its long-term benefit-risk profile. OBJECTIVE: Report the safety and tolerability of ofatumumab in RMS after extended treatment up to 3.5 years. METHODS: Patients completing ASCLEPIOS I/II (phase 3), APLIOS, or APOLITOS (phase 2) trials could enter ALITHIOS, a phase 3b, open-label, long-term safety study. We analyzed cumulative data of continuous ofatumumab treatment and of patients newly switched from teriflunomide. RESULTS: The safety population had 1969 patients: 1292 continuously treated with ofatumumab (median time-at-risk 35.5 months, 3253 patient-years) and 677 newly switched (median time-at-risk 18.3 months, 986 patient-years). A total of 1650 patients (83.8%) had ⩾1 adverse events and 191 (9.7%) had ⩾1 serious adverse events. No opportunistic infections or progressive multifocal leukoencephalopathy events were identified; the risk of malignancies was low. Mean serum immunoglobulin (Ig) G levels remained stable. Mean IgM levels decreased but remained above the lower limit of normal in most. Serious infection incidence was low; decreased Ig levels were not associated with serious infections. CONCLUSION: In patients with up to 3.5 years' exposure, ofatumumab was well tolerated, with no new safety risks identified. These findings, with its established effectiveness, support a favorable benefit-risk profile of ofatumumab in RMS.

Rapid and sustained B-cell depletion with subcutaneous ofatumumab in relapsing multiple sclerosis: APLIOS, a randomized phase-2 study.

BACKGROUND: Ofatumumab, the first fully human anti-CD20 monoclonal antibody, is approved in several countries for relapsing multiple sclerosis (RMS). OBJECTIVE: To demonstrate the bioequivalence of ofatumumab administered by an autoinjector versus a pre-filled syringe (PFS) and to explore the effect of ofatumumab on B-cell depletion. METHODS: APLIOS (NCT03560739) is a 12-week, open-label, parallel-group, phase-2 study in patients with RMS receiving subcutaneous ofatumumab 20 mg every 4 weeks (q4w) (from Week 4, after initial doses on Days 1, 7, and 14). Patients were randomized 10:10:1:1 to autoinjector or PFS in the abdomen, or autoinjector or PFS in the thigh, respectively. Bioequivalence was determined by area under the curve (AUCτ) and maximum plasma concentration (Cmax) for Weeks 8-12. B-cell depletion and safety/tolerability were assessed. RESULTS: A total of 256 patients contributed to the bioequivalence analyses (autoinjector-abdomen, n = 128; PFS-abdomen, n = 128). Abdominal ofatumumab pharmacokinetic exposure was bioequivalent for autoinjector and PFS (geometric mean AUCτ, 487.7 vs 474.1 h × µg/mL (ratio 1.03); Cmax, 1.409 vs 1.409 µg/mL (ratio 1.00)). B-cell counts (median cells/µL) depleted rapidly in all groups from 214.0 (baseline) to 2.0 (Day 14). Ofatumumab was well tolerated. CONCLUSION: Ofatumumab 20 mg q4w self-administered subcutaneously via autoinjector is bioequivalent to PFS administration and provides rapid B-cell depletion.

Statistical methodology for highly variable compounds: A novel design approach for the ofatumumab Phase 2 bioequivalence study.

This article describes a novel mixed-scaling testing strategy, in combination with an adaptive parallel-groups bioequivalence trial, to test pharmacokinetic equivalence of two formulations of a drug with highly variable pharmacokinetics. The methodology was applied to the Phase 2 APLIOS study in relapsing multiple sclerosis patients, where the bioequivalence of subcutaneous ofatumumab 20 mg administered via an autoinjector pen (test formulation) versus prefilled syringe (reference formulation) in the abdomen has been studied. Due to a high coefficient of variation (CV) of the relevant pharmacokinetic metrics (AUCtau and Cmax ) for the reference formulation (>30%), a reference-Scaled bioequivalence (RSABE) approach was applied but modified for a parallel-groups design. In the absence of regulatory guidance for applying RSABE in parallel-group designs, and in contrast to the available regulatory guidance for RSABE in cross-over trials, the suggested testing strategy uses the between-subject variability of the reference drug instead of the corresponding within-subject variability that would be available if a standard cross-over bioequivalence trial had been possible. Moreover, due to high uncertainty in the initial CV estimate for the sample size determination, a two-stage adaptive design was used, allowing for a sample size adjustment based on the pharmacokinetic variability observed at an interim analysis. The interim analysis timing was pre-specified based on simulations which included re-estimation of the final sample size at the end of the first stage to ensure sufficient power of the RSABE test at the end of the second stage. Using this approach, bioequivalence was shown between the test and reference formulations. The APLIOS trial is registered at ClinicalTrials.gov: NCT03560739.

Intravenous immunoglobulin significantly reduces exposure of concomitantly administered anti-C5 monoclonal antibody tesidolumab.

Awareness of drug-drug interactions is critical in organ transplant recipient management. However, biologic agents interfering with monoclonal antibodies is not widely considered. We report the effect of high-dose intravenous immunoglobulin (IVIg) on safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of the human anti-C5 monoclonal antibody tesidolumab (LFG316) in end-stage renal disease patients awaiting kidney transplant. In this single-center, phase 1, open-label, parallel-group study, 8 patients were assigned to receive either single-dose tesidolumab + IVIg or tesidolumab alone, with 56-day follow-up. Within-group PK parameters were consistent. Mean tesidolumab exposure decreased 34%, clearance increased 63%, and half-life decreased 41% comparing tesidolumab + IVIg to tesidolumab alone. IVIg influence on tesidolumab elimination was most evident in the first 3 weeks. Complete suppression of both total and alternative complement activities was maintained for 4 weeks in the tesidolumab alone group and for 2 weeks in the tesidolumab + IVIg group. Tesidolumab was well tolerated. IVIg infused before tesidolumab affected tesidolumab PK and PD, resulting in a shortened period of full complement activity inhibition. These findings suggest a clinically relevant impact of IVIg on monoclonal antibody clearance and indirectly hint at an IVIg mechanism of action in treating autoimmune diseases and allosensitization by accelerating pathogenic IgG antibody degradation. Trial registration number: NCT02878616.

Serum Neurofilament Light Trajectories and Their Relation to Subclinical Radiological Disease Activity in Relapsing Multiple Sclerosis Patients in the APLIOS Trial.

INTRODUCTION: Several studies have described prognostic value of serum neurofilament light chain (sNfL) at the group level in relapsing multiple sclerosis (RMS) patients. Here, we aimed to explore the temporal association between sNfL and development of subclinical disease activity as assessed by magnetic resonance imaging (MRI) at the group level and evaluate the potential of sNfL as a biomarker for capturing subclinical disease activity in individual RMS patients. METHODS: In the 12-week APLIOS study, patients (N = 284) received subcutaneous ofatumumab 20 mg. Frequent sNfL sampling (14 time points over 12 weeks) and monthly MRI scans enabled key analyses including assessment of the group-level temporal relationship of sNfL levels with on-study subclinical development of gadolinium-enhancing (Gd +)T1 lesions. Prognostic value of baseline sNfL ("high" vs. "low") level for subsequent on-study clinical relapse or Gd + T1 activity was assessed. Individual patient-level development of on-study Gd + T1 lesions was compared across three predictors: baseline Gd + T1 lesion number, baseline sNfL ("high" vs. "low"), and time-matched sNfL. RESULTS: In patients developing Gd + T1 lesions at week 4 (absent at baseline), sNfL levels increased during the month preceding the week-4 MRI scan and then gradually decreased back to baseline. High versus low baseline sNfL conferred increased risk of subsequent on-study clinical relapse or Gd + T1 activity (HR, 2.81; p < 0.0001) in the overall population and, notably, also in the patients without baseline Gd + T1 lesions (HR, 2.48; p = 0.0213). Individual patient trajectories revealed a marked difference in Gd + T1 lesions between patients with the ten highest vs. lowest baseline sNfL levels (119 vs. 19 lesions). Prognostic value of baseline or time-matched sNfL for on-study Gd + T1 lesions was comparable to that of the number of baseline MRI Gd + T1 lesions. CONCLUSIONS: sNfL measurement may have utility in capturing and monitoring subclinical disease activity in RMS patients. sNfL assessments could complement regular MRI scans and may provide an alternative when MRI assessment is not feasible. CLINICALTRIALS: GOV: NCT03560739. CLASSIFICATION OF EVIDENCE: This study provides class I evidence that serum neurofilament light may be used as a biomarker for monitoring subclinical disease activity in relapsing multiple sclerosis patients, as shown by its elevation in the weeks preceding the development of new gadolinium-enhancing T1 lesion activity.

Population Pharmacokinetic-B Cell Modeling for Ofatumumab in Patients with Relapsing Multiple Sclerosis.

BACKGROUND: Ofatumumab, a fully human anti-CD20 monoclonal antibody indicated for the treatment of relapsing forms of multiple sclerosis (RMS), binds to a unique conformational epitope, thereby depleting B cells very efficiently and allowing subcutaneous administration at lower doses. OBJECTIVES: The aims were to characterize the relationship between ofatumumab concentration and B cell levels, including the effect of covariates such as body weight, age, or baseline B cell count, and use simulations to confirm the chosen therapeutic dose. METHODS: Graphical and regression analyses previously performed based on data from a dose-range finding study provided the B cell depletion target used in the present work. All available adult phase 2/3 data for ofatumumab in RMS patients were pooled to develop a population pharmacokinetics (PK)-B cell count model, using nonlinear mixed-effects modeling. The population PK-B cell model was used to simulate B cell depletion and repletion times and the effect of covariates on PK and B cell metrics, as well as the dose response across a range of subcutaneous ofatumumab monthly doses. RESULTS: The final PK-B cell model was developed using data from 1486 patients. The predetermined B cell target was best achieved and sustained with the 20-mg dose regimen, with median B cell count reaching 8 cells/µL in 11 days and negligible repletion between doses. Only weight had a significant effect on PK, which did not translate into any clinically relevant effect on B cell levels. CONCLUSION: The PK-B cell modeling confirms the dose chosen for the licensed ofatumumab regimen and demonstrates no requirement for dose adjustment based on adult patient characteristics.

Effect of ofatumumab on pregnancy, parturition, and lactation in cynomolgus monkeys.

Knowledge of the impacts of the anti-CD20 monoclonal antibody ofatumumab on the developing immune system is limited. This study examined the effects of intravenous ofatumumab on pregnancy, parturition, and lactation, and on pre- and postnatal survival and development in cynomolgus monkeys, an established model for developmental toxicity assessment. Pregnant cynomolgus monkeys (n = 42) were randomized to receive vehicle only (control group; n = 14), low-dose ofatumumab (n = 14), or high-dose ofatumumab (n = 14). Survival, clinical outcomes, and clinical pathology investigations were evaluated regularly until lactation day (maternal animals) and postnatal day 180±1 (infants). Anatomic pathology was investigated in euthanized infants and unscheduled terminations of maternal animals and infants. Ofatumumab treatment was not associated with maternal toxicity or embryotoxicity and had no effect on the growth and development of offspring. As expected, B-cell depletion occurred in maternal animals and their offspring, with a reduced humoral immune response in infants of mothers on high-dose ofatumumab. Both effects were reversible. In the high-dose group, perinatal deaths of 3 infants were attributed to infections, potentially secondary to pharmacologically induced immunosuppression. The no-observed adverse-effect level for initial/maintenance ofatumumab doses was 100/20 mg, and 10/3 mg/kg for pharmacological effects in infant animals, which are associated with exposures significantly higher than those following therapeutic doses in humans. In this study with cynomolgus monkeys, ofatumumab treatment was not associated with maternal toxicity or embryotoxicity and had no effect on the growth and development of offspring.

Pharmacokinetics, tissue distribution and excretion of 40kDa PEG and PEGylated rFVIII (N8-GP) in rats.

The biologic fate of the [(3)H]PEG-moiety incorporated into N8-GP was evaluated based on single i.v. bolus doses to rats. Furthermore, the 40kDa [(3)H]PEG-moiety was given separately to rats by single i.v. bolus doses, to investigate if the pharmacokinetics were dose-dependent. For both compounds, plasma pharmacokinetics, distribution and excretion pathways were investigated, based on total radioactivity measurements ([(3)H]N8-GP: 0.17-4.1mg/kg;~1300-30,000U/kg, PEG load of ~0.03-0.7mg/kg); ([(3)H]PEG: 0.6, 1, 12, 100 and 200mg/kg). The plasma concentration of the intact N8-GP conjugate was also measured by ELISA. After single i.v. administration to rats, both [(3)H]N8-GP and [(3)H]PEG were shown to be widely distributed, mainly in highly vascularized tissues, with the lowest levels of radioactivity found in the CNS. Though a slow elimination of radioactivity was observed over the 12-week study period, approximately half of the radioactive dose of either compound was removed from the body 1week post-dose. The radioactivity was eliminated mainly via the kidney into urine but also via the liver into feces, with a larger fraction found in the feces for [(3)H]N8-GP. Elimination of the 40kDa PEG-moiety was shown to be dose-dependent with faster elimination at lower dose levels. The clinical dose of N8-GP provides a substantially lower PEG exposure (50-75U/kg; PEG load of <0.002mg/kg) when compared to the PEG doses investigated in this paper (0.03-200mg/kg). This may imply an even faster clearance of the PEG-moiety after N8-GP administration of clinically relevant doses.

The potential of nasal application for delivery to the central brain-a microdialysis study of fluorescein in rats.

Previous animal studies have shown that various types of nasally administered drugs and model substances can access the central nervous system (CNS) via direct transport across the olfactory epithelium, and thereby circumventing the blood-brain barrier (BBB). These compounds, however, have mainly been identified in the cerebrospinal fluid and the olfactory bulbs which are usually not pharmacologically relevant targets. The aim of the present study was to evaluate the potential of targeting the central brain by olfactory absorption by use of sodium fluorescein as a hydrophilic model substance with limited permeability across the blood-brain barrier. Microdialysis probes were implanted in blood and in right and left side of the brain (striatum) in rats. The pharmacokinetics of sodium fluorescein was studied from 0 to 180min following intravenous and unilateral nasal administration without occlusion of the oesophagus. Pharmacokinetic modelling showed a significantly higher absorption rate and lower T(max) in the ipsilateral striatum (0.097min(-1) and 41min) compared with the contralateral side (0.056min(-1) and 54min). The rate of elimination in brain was significantly lower after nasal administration (0.004min(-1)) compared with intravenous administration (0.012min(-1)). However, the brain to plasma area under the curve ratios of model substance were low (2-3%) and not significantly different between right and left side of the brain, regardless of the route of administration. The results obtained by microdialysis were supported by findings in whole brain homogenates where concentrations of fluorescein were approximately 40% higher in the right striatum compared with the left side initially after nasal administration to the right nostril of rats. Despite some indications of olfactory transport to the central rat brain it was concluded that the drug targeting potential of sodium fluorescein and most likely other hydrophilic compounds is limited.

Acyclovir prodrug for the intestinal di/tri-peptide transporter PEPT1: comparison of in vivo bioavailability in rats and transport in Caco-2 cells.

It has previously been shown that the prodrug Glu(acyclovir)-Sar has a high affinity for PEPT1 in Caco-2 cells. However, affinity does not necessarily lead to translocation by the transporter which is necessary for achieving an increased oral bioavailability. Therefore i.v. and p.o. doses of Glu(acyclovir)-Sar, acyclovir and valacyclovir were given to rats and the collected blood samples were analysed via LC-MS-MS. Furthermore, Caco-2 cell monolayers were exposed apically to Glu(acyclovir)-Sar, acyclovir, and valacyclovir and the concentration of drug and prodrugs in the cell extracts were determined and taken as a measure for intracellular accumulation. In addition, bi-directional transport studies of Glu(acyclovir)-Sar across Caco-2 cell monolayers and in vitro metabolism studies of Glu(acyclovir)-Sar in various media of rat origin were performed. For these purposes HPLC-UV analysis was applied. Oral administration of Glu(acyclovir)-Sar to rats resulted in low bioavailabilities of acyclovir (<2%) and intact prodrug (<5%). Studies performed on Caco-2 cell monolayers showed that in contrast to valacyclovir Glu(acyclovir)-Sar did not result in a detectable amount of acyclovir or Glu(acyclovir)-Sar in the cell extracts. Bi-directional flux across Caco-2 cell monolayers apical to basolateral (FluxA-->B) and basolateral to apical (FluxB-->A) was measured and the FluxB-->A/FluxA-->B ratios of approximately 0.8 indicate that apical efflux mechanisms may not explain this lack of intracellular accumulation. These data indicate that Glu(acyclovir)-Sar may not be translocated by PEPT1.

A microdialysis model to examine nasal drug delivery and olfactory absorption in rats using lidocaine hydrochloride as a model drug.

Targeting of the central nervous system by direct drug transport from the nose to the brain has gained increased attention through the last decade. In the present study, a model for olfactory drug absorption has been investigated using intravenous and unilateral nasal administration of lidocaine hydrochloride in rats. To investigate the possible drug delivery aspects of this route of transport to a central part of the brain a microdialysis model using in vivo recovery by calibrator was applied to the systemic blood and to right and left striatum. The integrity of the blood-brain barrier was evaluated following microdialysis probe implantation. The in vivo experiments were carried out as a cross-over study in rats. The drainage from the nasal cavity was not restricted by occlusion. It was found that true unbound lidocaine concentrations could be calculated from in vivo recovery measurements of retrodialysis of prilocaine hydrochloride. The relative in vivo recoveries in striatum (11.3%) and blood (24.0%) were significantly lower than in vitro (31.3 and 44.9%). The blood-brain barrier was found to retain its physical integrity when evaluated one hour after probe implantation. From pharmacokinetic modelling of the time-concentration curves it was found that the absorption rates and area under the curve (AUC) values of lidocaine in left and right striatum were not statistically different following nasal and intravenous administration, respectively. The average nasal bioavailabilities of lidocaine in blood, left and right striatum were 85, 103 and 129%, respectively. It was concluded that no significant olfactory absorption to striatum was evident in the present study. However, the method should be applicable to studies of drug delivery to blood and brain following nasal administration of other drugs.

Human glucagon receptor antagonists with thiazole cores. A novel series with superior pharmacokinetic properties.

The aim of the work presented here was to design and synthesize potent human glucagon receptor antagonists with improved pharmacokinetic (PK) properties for development of pharmaceuticals for the treatment of type 2 diabetes. We describe the preparation of compounds with cyclic cores (5-aminothiazoles), their binding affinities for the human glucagon and GIP receptors, as well as affinities for rat, mouse, pig, dog, and monkey glucagon receptors. Generally, the compounds had slightly less glucagon receptor affinity compared to compounds of the previous series, but this was compensated for by much improved PK profiles in both rats and dogs with high oral bioavailabilities and sustained high plasma exposures. The compounds generally showed species selectivity for glucagon receptor binding with poor affinities for the rat, mouse, rabbit, and pig receptors. However, dog and monkey glucagon receptor affinities seem to reflect the human situation. One compound of this series, 18, was tested intravenously in an anesthetized glucagon-challenged monkey model of hyperglucagonaemia and hyperglycaemia and was shown dose-dependently to decrease glycaemia. Further, high plasma exposures and a long plasma half-life (5.2 h) were obtained.