Post-intervention Status in Patients With Refractory Myasthenia Gravis Treated With Eculizumab During REGAIN and Its Open-Label Extension

OBJECTIVE: To evaluate whether eculizumab helps patients with anti-acetylcholine receptor-positive (AChR+) refractory generalized myasthenia gravis (gMG) achieve the Myasthenia Gravis Foundation of America (MGFA) post-intervention status of minimal manifestations (MM), we assessed patients' status throughout REGAIN (Safety and Efficacy of Eculizumab in AChR+ Refractory Generalized Myasthenia Gravis) and its open-label extension. METHODS: Patients who completed the REGAIN randomized controlled trial and continued into the open-label extension were included in this tertiary endpoint analysis. Patients were assessed for the MGFA post-intervention status of improved, unchanged, worse, MM, and pharmacologic remission at defined time points during REGAIN and through week 130 of the open-label study. RESULTS: A total of 117 patients completed REGAIN and continued into the open-label study (eculizumab/eculizumab: 56; placebo/eculizumab: 61). At week 26 of REGAIN, more eculizumab-treated patients than placebo-treated patients achieved a status of improved (60.7% vs 41.7%) or MM (25.0% vs 13.3%; common OR: 2.3; 95% CI: 1.1-4.5). After 130 weeks of eculizumab treatment, 88.0% of patients achieved improved status and 57.3% of patients achieved MM status. The safety profile of eculizumab was consistent with its known profile and no new safety signals were detected. CONCLUSION: Eculizumab led to rapid and sustained achievement of MM in patients with AChR+ refractory gMG. These findings support the use of eculizumab in this previously difficult-to-treat patient population. CLINICALTRIALSGOV IDENTIFIER: REGAIN, NCT01997229; REGAIN open-label extension, NCT02301624. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that, after 26 weeks of eculizumab treatment, 25.0% of adults with AChR+ refractory gMG achieved MM, compared with 13.3% who received placebo

Minimal Symptom Expression' in Patients With Acetylcholine Receptor Antibody-Positive Refractory Generalized Myasthenia Gravis Treated With Eculizumab

The efficacy and tolerability of eculizumab were assessed in REGAIN, a 26-week, phase 3, randomized, double-blind, placebo-controlled study in anti-acetylcholine receptor antibody-positive (AChR+) refractory generalized myasthenia gravis (gMG), and its open-label extension

Surfactant Uptake Dynamics in Mammalian Cells Elucidated with Quantitative Coherent Anti-Stokes Raman Scattering Microspectroscopy

International audienceThe mechanism of surfactant-induced cell lysis has been studied with quantitative coherent anti-Stokes Raman scattering (CARS) microspectroscopy. The dynamics of surfactant molecules as well as intracellular biomolecules in living Chinese Hamster Lung (CHL) cells has been examined for a low surfactant concentration (0.01 w%). By using an isotope labeled surfactant having CD bonds, surfactant uptake dynamics in living cells has been traced in detail. The simultaneous CARS imaging of the cell itself and the internalized surfactant has shown that the surfactant molecules is first accumulated inside a CHL cell followed by a sudden leak of cytosolic components such as proteins to the outside of the cell. This finding indicates that surfactant uptake occurs prior to the cell lysis, contrary to what has been believed: surface adsorption of surfactant molecules has been thought to occur first with subsequent disruption of cell membranes. Quantitative CARS microspectroscopy enables us to determine the molecular concentration of the surfactant molecules accumulated in a cell. We have also investigated the effect of a drug, nocodazole, on the surfactant uptake dynamics. As a result of the inhibition of tubulin polymerization by nocodazole, the surfactant uptake rate is significantly lowered. This fact suggests that intracellular membrane trafficking contributes to the surfactant uptake mechanism

Surfactant uptake dynamics in mammalian cells elucidated with quantitative coherent anti-stokes Raman scattering microspectroscopy.

The mechanism of surfactant-induced cell lysis has been studied with quantitative coherent anti-Stokes Raman scattering (CARS) microspectroscopy. The dynamics of surfactant molecules as well as intracellular biomolecules in living Chinese Hamster Lung (CHL) cells has been examined for a low surfactant concentration (0.01 w%). By using an isotope labeled surfactant having CD bonds, surfactant uptake dynamics in living cells has been traced in detail. The simultaneous CARS imaging of the cell itself and the internalized surfactant has shown that the surfactant molecules is first accumulated inside a CHL cell followed by a sudden leak of cytosolic components such as proteins to the outside of the cell. This finding indicates that surfactant uptake occurs prior to the cell lysis, contrary to what has been believed: surface adsorption of surfactant molecules has been thought to occur first with subsequent disruption of cell membranes. Quantitative CARS microspectroscopy enables us to determine the molecular concentration of the surfactant molecules accumulated in a cell. We have also investigated the effect of a drug, nocodazole, on the surfactant uptake dynamics. As a result of the inhibition of tubulin polymerization by nocodazole, the surfactant uptake rate is significantly lowered. This fact suggests that intracellular membrane trafficking contributes to the surfactant uptake mechanism

Accumulation of SDS in a CHL cell and subsequent cellular death.

<p><b>A</b>. Time-resolved Im[χ⁽³⁾] spectra obtained with the summation over all the spectra in the cell shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0093401#pone-0093401-g003" target="_blank">Fig. 3</a>. Time-profiles of band amplitudes at 2100 cm⁻¹ (<b>B</b>), 2930 cm⁻¹ (<b>C</b>), 2850 cm⁻¹ (<b>D</b>), 1655 cm⁻¹ (<b>E</b>), 1446 cm⁻¹ (<b>F</b>) and 1003 cm⁻¹ (<b>G</b>).</p

SDS molecules are condensed in a CHL cell.

<p><b>A</b>. The molecular structure of d₂₅-SDS. <b>B</b>. Im[χ⁽³⁾] spectrum obtained from one point of a CHL cell indicated as the cross in the inset several minutes after the addition of d₂₅-SDS. <b>C</b>. The expanded spectrum of <b>B</b>. <b>D</b>. Im[χ⁽³⁾] spectrum of 1% d₂₅- SDS aqueous solution. The exposure time for <b>B</b>–<b>D</b> is 50 msec and <b>B</b>–<b>D</b> are measured under the same experimental condition.</p

Im[χ⁽³⁾] spectra and images from a CHL cell.

<p>Im[χ⁽³⁾] spectra from the two points of the CHL cell. <b>A</b> and <b>B</b> are obtained from the points indicated as × and + in <b>C</b>, respectively. The inset of each spectrum is the expanded spectrum in the fingerprint region. The exposure time is 50 msec. Im[χ⁽³⁾] images at 2930 cm⁻¹ (<b>C</b>), 2850 cm⁻¹ (<b>D</b>), 2655 cm⁻¹ (<b>E</b>), 2446 cm⁻¹ (<b>F</b>) and 1003 cm⁻¹ (<b>G</b>), respectively. The scale bar in the image is 10 µm. The image consists of 91×81 pixels and the exposure time for each pixel is 50 msec. Each image is normalized at the intensity maximal of each band.</p

The concentration dependence of d₂₅-SDS cell lysis efficiency; ++ corresponds to clear cell lysis, +: moderate cell lysis, −: remaining stable.

<p>The concentration dependence of d₂₅-SDS cell lysis efficiency; ++ corresponds to clear cell lysis, +: moderate cell lysis, −: remaining stable.</p

Time-resolved Im[χ⁽³⁾] images of the CHL cell with the surfactant.

<p>The scale bar in the image is 10 µm. The image consists of 71×51 pixels and the exposure time for each pixel is 50 msec. Each row of the CARS images is measured every 3.5 min. Each column is normalized at the intensity maximal of each band.</p