Efficacy of ravulizumab in patients with generalized myasthenia gravis by time from diagnosis: A post hoc subgroup analysis of the CHAMPION MG study.

INTRODUCTION/AIMS: The CHAMPION MG study demonstrated that ravulizumab significantly improved Myasthenia Gravis-Activities of Daily Living (MG-ADL) and Quantitative Myasthenia Gravis (QMG) total scores versus placebo in adults with acetylcholine receptor antibody-positive generalized myasthenia gravis (AChR+ gMG). This post hoc analysis aimed to assess these outcomes by time from MG diagnosis. METHODS: Changes from baseline to week 26 in MG-ADL and QMG total scores were analyzed by time from MG diagnosis to study entry (≤2 vs. >2 years). Within each subgroup, least-squares (LS) mean changes for ravulizumab and placebo were compared using mixed models for repeated measures. RESULTS: In ravulizumab-treated patients, differences in LS mean (standard error of the mean) changes from baseline to week 26 were not statistically significant in the ≤2-years subgroup versus the >2-years subgroup for MG-ADL (-4.3 [0.70] vs. -2.9 [0.37]; p = .0511) or QMG (-4.3 [0.94] vs. -2.5 [0.50]; p = .0822) scores. No clear trends were observed in the placebo group. LS mean changes from baseline were significantly greater for ravulizumab versus placebo in both the ≤2 and >2 years from diagnosis subgroups for MG-ADL and QMG scores (all p < .05). The difference in treatment effect between the ≤2-years and >2-years subgroups was not statistically significant. No clinically meaningful between-subgroup differences in treatment-emergent adverse events were observed in ravulizumab-treated patients. DISCUSSION: Ravulizumab treatment improved clinical outcomes for patients with AChR+ gMG regardless of time from diagnosis. A numerical trend was observed favoring greater treatment effect with earlier versus later treatment after diagnosis. Further studies are required for confirmation.

Summary of Research: Terminal Complement Inhibitor Ravulizumab in Generalized Myasthenia Gravis.

This article provides a summary of a previously published paper: Terminal Complement Inhibitor Ravulizumab in Generalized Myasthenia Gravis. The paper reported the results of the CHAMPION-MG trial which investigated the drug ravulizumab in the rare disease, myasthenia gravis. Terminal Complement Inhibitor Ravulizumab in Generalized Myasthenia Gravis (MP4 594600 KB).

Ravulizumab pharmacokinetics and pharmacodynamics in patients with generalized myasthenia gravis.

INTRODUCTION: The terminal complement C5 inhibitor ravulizumab has a long elimination half-life, allowing maintenance dosing every 8 weeks. In the 26-week, double-blind, randomized, placebo-controlled period (RCP) of the CHAMPION MG study, ravulizumab provided rapid and sustained efficacy and was well tolerated in adults with anti-acetylcholine receptor antibody-positive (AChR Ab+) generalized myasthenia gravis (gMG). This analysis evaluated the pharmacokinetics (PK), pharmacodynamics (PD), and potential immunogenicity of ravulizumab in adults with AChR Ab+ gMG. METHODS: Data were analyzed from 86 patients who received ravulizumab in the CHAMPION MG RCP. Ravulizumab dosing was weight-based: initial loading dose of 2400/2700/3000 mg on Day 1 and maintenance doses of 3000/3300/3600 mg on Day 15 and then every 8 weeks. PK parameters were estimated from serum ravulizumab concentrations determined pre- and post-dose; PD effects of ravulizumab on serum free C5 concentrations were measured; and immunogenicity was assessed using anti-drug antibody and neutralizing-antibody assays. RESULTS: Target serum ravulizumab concentrations (> 175 µg/mL) were achieved immediately after the first ravulizumab dose (within 30 min of infusion completion) and maintained throughout the 26-week treatment period irrespective of patient body weight. Following the final maintenance dose, mean Cmax was 1548 µg/mL and Ctrough 587 µg/mL; no meaningful differences were noted among body-weight categories. Inhibition of serum free C5 was immediate, complete (< 0.5 µg/mL), and sustained throughout treatment in all patients. No treatment-emergent anti-drug antibodies were observed. CONCLUSIONS: PK/PD evidence supports the use of ravulizumab every 8 weeks for immediate, complete, and sustained inhibition of terminal complement C5 in adults with AChR Ab+ gMG. TRIAL REGISTRATION: ClinicalTrials.gov ID: NCT03920293 (April 18, 2019).

Terminal Complement Inhibitor Ravulizumab in Generalized Myasthenia Gravis.

BACKGROUND: Generalized myasthenia gravis (gMG) is a rare, chronic, and debilitating autoimmune disease. Activation of the complement system by autoantibodies against the postsynaptic acetylcholine receptor (AChR) leads to destruction of the postsynaptic membrane and disruption of neuromuscular transmission. This trial evaluated ravulizumab, a long-acting inhibitor of terminal complement protein C5, as a treatment for gMG. METHODS: In this randomized, double-blind, placebo-controlled, multinational trial, we randomly assigned (1:1) patients with anti-AChR antibody-positive gMG to intravenous ravulizumab or placebo for 26 weeks. Patients received a loading dose on day 1, followed by maintenance doses on day 15 and every 8 weeks thereafter. The primary end point and first secondary end point (change from baseline to week 26 in patient-reported Myasthenia Gravis­Activities of Daily Living [MG-ADL] scale and clinician-reported Quantitative Myasthenia Gravis [QMG] total scores, respectively) were compared between the ravulizumab- and placebo-treated groups. RESULTS: In total, 175 patients were enrolled. Ravulizumab significantly increased the magnitude of mean changes from baseline to week 26 versus placebo in MG-ADL (−3.1 vs. −1.4; P<0.001) and QMG (−2.8 vs. −0.8; P<0.001) total scores. Improvements in both measures occurred within 1 week of ravulizumab initiation and were sustained through week 26. QMG total scores improved by 5 points or more in a significantly greater proportion of ravulizumab-treated patients than of those receiving placebo (30.0% vs. 11.3%; P=0.005). No notable differences in adverse events were observed. CONCLUSIONS: Ravulizumab demonstrated rapid and sustained improvements in both patient- and clinician-reported outcomes and had a side effect and adverse-event profile that did not limit treatment in adults with anti-AChR antibody-positive gMG. (Funded by Alexion, AstraZeneca Rare Disease; ClinicalTrials.gov number, NCT03920293; EudraCT number, 2018-003243-39.)

Prospective Evaluation of Patients With X-Linked Retinoschisis During 18 Months.

Purpose: Prospective evaluation of patients with X-linked retinoschisis (XLRS). Methods: Fifty-six males XLRS patients, age ≥7 years, had retinal structure and function tests performed every 6 months during an 18-month period. Results: Best corrected visual acuity (BCVA) was abnormal (mean ± SD logMAR 0.57 ± 0.32 OD and 0.50 ± 0.27 OS), with weak correlation between visual acuity and age (R = -0.24, P = 0.0095). Mean cyst cavity volume (CCV) determined on optical coherence tomography showed weak correlation with age (R = -0.33, P = 0.0009) and no correlation with visual acuity. Subjects had modest reduction in mean kinetic and static perimetry results, reduced b-wave amplitude on electroretinography, abnormal reading speed results, and decreased visual function quality of life scores. Contrast sensitivity results were normal in 85 of 99 eyes tested. Most subjects had no meaningful change in BCVA during follow-up. Subjects who started carbonic anhydrase inhibitor (CAI) treatment at enrollment had improved BCVA (mean ± SD change 3.15 ± 7.8 ETDRS letters, with increase of ≥15 ETDRS letters at 8 of 110 visits [in 3 subjects]). There were no significant changes in other parameters tested. Conclusions: Structural and functional results were stable during the 18-month follow-up period. Some patients starting CAI treatment at the baseline visit showed improvement in BCVA that was not correlated with changes in CCV. Natural history data such as these will be important for comparisons to the changes in measures of retinal structure and function following gene replacement therapy in patients with XLRS.

Results at 5 Years After Gene Therapy for RPE65-Deficient Retinal Dystrophy.

Previously, results at 2 years after subretinal injection of a recombinant adeno-associated virus vector expressing RPE65 (rAAV2-CB-hRPE65) in eight adults and four children with retinal degeneration caused by RPE65 mutations were reported. Now, results at 5 years after treatment in 11 of these subjects are reported. Subjects received a subretinal injection of rAAV2-CB-hRPE65 in the poorer-seeing eye, at either of two dose levels, and were followed for 5 years after treatment. The primary safety outcomes were ocular and non-ocular adverse events. Efficacy outcomes included changes in best corrected visual acuity, static perimetry hill of vision measurements for the central 30° (V30), and total (VTOT) visual field and kinetic perimetry visual field area. The only adverse events reported during years 3, 4, and 5 were minor intercurrent illnesses. Pediatric subjects had improvement in visual acuity and static perimetry in the treated eye, sometimes with a smaller improvement in the untreated eye, during the first 2 years of the study that persisted during years 3-5, with no consistent changes in kinetic perimetry during the study. Most adult subjects had no consistent changes in visual acuity or static perimetry during the study. Three adult subjects with markedly abnormal baseline kinetic visual field area had improvement in the treated eye during the first 1-2 years after treatment, but the absolute magnitude of the improvement was small and was not sustained at subsequent visits. There were no clinically significant adverse events. Visual acuity and static perimetry testing results suggest that treating patients at a younger age is associated with better visual function outcomes during 5 years after treatment.

Computer Modeling of Spin Labels: NASNOX, PRONOX, and ALLNOX.

Measurement of distances between spin labels using electron paramagnetic resonance with the double electron-electron resonance (DEER) technique is an important method for evaluation of biomolecular structures. Computation of interlabel distances is of value for experimental planning, validation of known structures using DEER-measured distances, and determination of theoretical data for comparison with experiment. This requires steps of building labels at two defined sites on proteins, DNA or RNA; calculation of allowable label conformers based on rotation around torsional angles; computation of pairwise interlabel distances on a per conformer basis; and calculation of an average distance between the two label ensembles. We have described and validated two programs for this purpose: NASNOX, which permits computation of distances between R5 labels on DNA or RNA; and PRONOX, which similarly computes distances between R1 labels on proteins. However, these programs are limited to a specific single label and single target types. Therefore, we have developed a program, which we refer to as ALLNOX (Addition of Labels and Linkers), which permits addition of any label to any site on any target. The main principle in the program is to break the molecular system into a "label," a "linker," and a "target." The user can upload a "label" with any chemistry, define a "linker" based on a SMILES-like string, and then define the "target" site. The flexibility of ALLNOX facilitates theoretical evaluation of labels prior to synthesis and accommodates evaluation of experimental data in biochemical complexes containing multiple molecular types.

Cardiorespiratory fitness does not alter plasma pentraxin 3 and cortisol reactivity to acute psychological stress and exercise.

Pentraxin 3 (PTX3) has been recently identified as a biomarker of vascular inflammation in predicting cardiovascular events. The purpose of this study was to examine the effect of cardiorespiratory fitness on plasma PTX3 and cortisol responses to stress, utilizing a dual-stress model. Fourteen male subjects were classified into high-fit (HF) and low-fit (LF) groups and completed 2 counterbalanced experimental conditions. The exercise-alone condition (EAC) consisted of cycling at 60% maximal oxygen uptake for 37 min, while the dual-stress condition (DSC) included 20 min of a mental stress while cycling for 37 min. Plasma PTX3 revealed significant increases over time with a significant elevation at 37 min in both HF and LF groups in response to EAC and DSC. No difference in plasma PTX3 levels was observed between EAC and DSC. In addition, plasma cortisol revealed a significant condition by time interaction with greater levels during DSC at 37 min, whereas cardiorespiratory fitness level did not reveal different plasma cortisol responses in either the EAC or DSC. Aerobic exercise induces plasma PTX3 release, while additional acute mental stress, in a dual-stress condition, does not exacerbate or further modulate the PTX3 response. Furthermore, cardiorespiratory fitness may not affect the stress reactivity of plasma PTX3 to physical and combined physical and psychological stressors. Finally, the exacerbated cortisol responses to combined stress may provide the potential link to biological pathways that explain changes in physiological homeostasis that may be associated with an increase in the risk of cardiovascular disease.

Chitin enhances obese inflammation ex vivo.

Infection has been implicated as a co-risk factor for obesity, but the mechanism remains uncertain. Elevated levels of plasma chitinase 3-like 1 (CHI3L1) are found in obese individuals. Since CHI3L1 is produced by activated immune cells including macrophages and recognizes microbial N-acetylglucosamine polymer (chitin), we asked whether the plasma CHI3L1 protein change in obese individuals might alter their innate immune response to chitin. Thirty-six subjects (15 obese and 21 non-obese), ages 18-30 years, were recruited. Peripheral blood mononuclear cells (PBMCs) were cultured with chitin microparticles (CMP; 1-10 µm) for 24h; tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), and CHI3L1 in the culture supernatants were measured. We chose CMP, since neither large chitin beads (40-100 µm), chitosan microparticles (1-10 µm), nor soluble chitin induced the cytokine/CHI3L1 production by PBMCs isolated from non-obese PBMCs ex vivo. We found that the quantity of IL-6, but not TNF-α or CHI3L1, induced by CMP was significantly correlated with plasma IL-6, BMI, waist/hip circumferences, fasting plasma insulin, and insulin resistance. These findings suggest that chitin, a substrate of CHI3L1, further promotes obese inflammation in a size- and chemical composition- dependent manner.

The influence of rehydration mode after exercise dehydration on cardiovascular function.

Our purpose was to compare the common modes of rehydration (REHY) on cardiovascular and fluid regulation recovery after exercise dehydration (EXDE). Twelve nonheat-acclimatized trained subjects (age: 23 ± 4 years, weight: 81.3 ± 3.7 kg, height: 180 ± 6 cm, V[Combining Dot Above]O2max: 56.9 ± 4.4 ml·min·kg , and body fat: 7.8 ± 3.0%) completed 20-hour fluid restriction and 2-hour EXDE to -4% body mass, and then were rehydrated to -2% body mass in a randomized, crossover design. The REHY methods included no fluid (NF), ad libitum, oral (OR), intravenous (IV), and a combination of IV and OR (IV + OR) of 1/2-normal saline (0.45% NaCl). The REHY occurred for 30 minutes, and the subjects were observed during rest for 30 minutes. Seated, standing, and mean arterial pressure (MAP) and blood pressure (BP) were measured every 15 minutes throughout REHY. Heart rate (HR), plasma arginine vasopressin concentration [AVP], and thirst perception were measured throughout REHY. The EXDE resulted in a body mass loss of 4.32 ± 0.22%. The REHY returned the subjects to -2.13 ± 0.47% body mass for controlled trials. Seated systolic BP was greater for IV + OR compared with that for OR (p = 0.015). Seated systolic BP and MAP during REHY showed that IV + OR was greater than OR, independent of time (p ≤ 0.011). Upon standing, IV + OR demonstrated a greater BP than both NF (p = 0.012) and OR (p = 0.031) did. The HR was reduced by IV and IV + OR to a greater extent than NF at REHY30 and REHY60 (p < 0.05). The IV + OR [AVP] demonstrated a strong trend for decreasing over time (p = 0.054) and was significantly less than NF at REHY60 (p = 0.003). Practical application seeking to restore cardiovascular function after EXDE, the combined use of IV + OR rather than a single REHY method seems to be most expedient.

IGF-I measurement across blood, interstitial fluid, and muscle biocompartments following explosive, high-power exercise.

Insulin-like growth factor-I (IGF-I) resides across different biocompartments [blood, interstitial fluid (ISF), and muscle]. Whether circulating IGF-I responses to exercise reflect local events remains uncertain. We measured the IGF-I response to plyometric exercise across blood, ISF, and muscle biopsy from the vastus lateralis. Twenty volunteers (8 men, 12 women, 22 ± 1 yr) performed 10 sets of 10 plyometric jump repetitions at a 40% 1-repetition maximum. Blood, ISF, and muscle samples were taken pre- and postexercise. Circulating IGF-I increased postexercise: total IGF-I (preexercise = 546 ± 42, midexercise = 585 ± 43, postexercise = 597 ± 45, +30 = 557 ± 42, +60 = 536 ± 40, +120 = 567 ± 42 ng/ml; midexercise, postexercise, and +120 greater than preexercise, P < 0.05); Free IGF-I (preexercise = 0.83 ± 0.09, midexercise = 0.78 ± 0.10, postexercise = 0.79 ± 0.11, +30 = 0.93 ± 0.10, +60 = 0.88 ± 0.10, + 120 = 0.91 ± 0.11 ng/ml; +30 greater than all other preceding time points, P < 0.05). No exercise-induced changes were observed for ISF IGF-I (preexercise = 2.35 ± 0.29, postexercise = 2.46 ± 0.35 ng/ml). No changes were observed for skeletal muscle IGF-I protein, although IGF-I mRNA content increased ∼40% postexercise. The increase in circulating total and free IGF-I was not correlated with increases in ISF IGF-I or muscle IGF-I protein content. Our data indicate that exercise-induced increases in circulating IGF-I are not reflective of local IGF-I signaling.

Changes in serum collagen markers, IGF-I, and knee joint laxity across the menstrual cycle.

Variations in serum markers of collagen production (CICP) and degradation (ICTP), insulin-like growth factor I (IGF-I) and anterior knee laxity (AKL) were measured in 20 women [10 with spontaneous cycles (eumenorrheic), 10 using oral contraceptives] over 5 consecutive days at menses (M1-M5, 1st pill week), the initial estrogen rise near ovulation (O1-O5, 2nd pill week), the initial progesterone rise of the early luteal phase (EL1-EL5, 3rd pill week) and post-progesterone peak of the late luteal phase (LL1-LL5, 4th pill week). ICTP was higher in oral contraceptive women (5.3 ± 1.7 vs. 3.7 ± 1.3 µg/L; p = 0.030), primarily during days near ovulation and the early luteal phase when concentrations decreased in eumenorrheic women (p = 0.04). IGF-I concentrations increased during menses then decreased and remained lower during the early and late luteal phase in oral contraceptive women, resulting in lower concentrations compared to eumenorrheic women at EL2 and LL1 (p = 0.03). CICP decreased in early and late luteal days (p <0.01), and there was a trend toward lower concentrations in eumenorrheic versus oral contraceptive women (85.7 ± 35.7 ng/ml vs. 123.2 ± 49.8 ng/ml; p = 0.07). Lower CICP and greater IGF-I concentrations predicted greater AKL across the 20 cycle days in both groups (R(2) = 0.310 and 0.400). Sex hormone concentration changes across the menstrual cycle are of sufficient magnitude to influence collagen metabolism, and may indirectly influence knee structure and function.

Appearance of D2O in sweat after oral and oral-intravenous rehydration in men.

Intravenous (IV) rehydration is common in athletics, but its thermoregulatory benefits and ergogenicity have not been elucidated. Availability of orally ingested fluid is dependent on gastric emptying and intestinal absorption rate. Deuterium oxide (D2O) has been used to demonstrate that fluid ingested during exercise appears in sweat within 10 minutes. The purpose of this study was to determine the effect of concurrent IV rehydration on D2O appearance in sweat samples after per ora rehydration with D2O labeled fluid. We hypothesized that the combination method would not be superior to the oral method. Ten fit men (age 23 ± 4, VO2max 59.49 ± 4.09 L·min(-1)) underwent 20 hours of fluid restriction resulting in 1.95 ± 0.25% body weight loss before beginning treadmill exercise and cycling. Exercise was performed in an environmental chamber (35.6 ± 0.2° C, 35.0 ± 1.8% relative humidity) for 2 hours at 55% VO2max, and the participants exhibited a mean body weight deficit of 4.50 ± 0.04%. Thermoregulatory measures were recorded while subjects were rehydrated with oral (OR) or oral combined with intravenous (IVO) fluid traced with D2O. After 30 minutes of rehydration and 30 minutes of seated recovery, the subjects began treadmill exercise at 55-60% VO2max. Forehead sweat samples were collected 0, 5, 10, 20, and 75 minutes from the start of rehydration. The samples were analyzed for D2O via isotope ratio mass spectrometry. D2O did not appear in the sweat within 20 minutes of rehydration; however, it did appear during the subsequent exercise bout. There was no significant difference between rehydration modes. Plasma volume increases and decreased volume of orally ingested fluid did not significantly alter transit time from ingestion to appearance in excreted sweat. The IVO method does not appear to be superior to the traditional OR method of rehydration.

The effect of oral vs. Intravenous rehydration on circulating myoglobin and creatine kinase.

Physical activity of significant intensity and duration may cause varying degrees of skeletal muscle damage, but it is unclear whether mode of rehydration will attenuate muscle tissue disruption caused by exercise in the heat. To examine the effects of the mode of rehydration on markers of muscle damage (myoglobin and creatine kinase [CK]), 11 healthy active men (age = 23 +/- 4 years, body mass = 80.9 +/- 3.9 kg, height = 180.5 +/- 5.4 cm) completed 4 experimental trials consisting of an exercise dehydration protocol (to -4% of baseline body mass), followed by a rehydration period (oral, intravenous [IV], oral and IV combined, and ad libitum), and finishing with an intense exercise challenge that included treadmill running and sprinting and a box lifting protocol. During rehydration, subjects returned to -2% of baseline body mass unless completing the ad libitum trial during which they consumed fluids as thirst dictated. Myoglobin (Mb) and CK were measured during euhydrated rest. Post-exercise blood was drawn at 1 and 24 hours post exercise challenge for Mb and CK, respectively. Urine was collected during euhydrated rest and 1-hour post exercise challenge for measurement of Mb clearance. Mb concentrations increased significantly from pre (1.06 +/- 0.20, 0.88 +/- 0.07, 1.15 +/- 0.25 and 0.92 +/- 0.06 nmol.L) to post (1.52 +/- 0.28, 1.44 +/- 0.11, 1.71 +/- 0.45 and 1.58 +/- 0.39) for IV, oral, oral and IV combined, and ad libitum, respectively, but were not significantly different among trials. Serum CK concentrations remained within the normal physiological range for all trials. Thus, despite previous research that clearly indicates the benefit of ingesting fluids during exercise to attenuate muscle damage, there were no significant differences between the modes of rehydration on circulating Mb and CK.