Daclizumab

We conducted a systematic review of immunomodulatory DMTs for MS. The PubMed search filter “clinical trial” and the key words “multiple sclerosis,” in combination with “interferon” (n = 842), “glatiramer acetate” (n = 192), “fingolimod” (n = 67), “dimethyl fumarate” (n = 18), “teriflunomide” (n = 15), “mitoxantrone” (n = 52), “daclizumab” (n = 29), “natalizumab” (n = 86), “alemtuzumab” (n = 23), “rituximab” (n = 15), “ocrelizumab” (n = 3), “laquinimod” (n = 10), and “siponimod” (n = 1) were used for screening relevant studies. In addition, we searched the public domain (including Clinicaltrials.gov) for non-PubMed sources with complete efficacy data on drugs currently under development. The inclusion criteria for selecting the trials were (1) randomized clinical trial in any MS subtype, (2) double-blinded or rater-blinded trial, (3) trial duration of at least a year (when counted in weeks, at least 48 weeks), (4) comparison between drug and placebo or between a drug and an active comparator (interferon beta), (5) the proportion of patients with confirmed disability progression (CDP; a change in EDSS confirmed in a subsequent follow-up visit after 3 or 6 months) measured in both groups as an outcome in the study, and (6) in trials with two arms, at least one arm of the trial used the FDA-approved dose of the drug (this arm was chosen for the analyses). The PRISMA flowchart (21 (link)) (Figure 1) provides details regarding the disposition of screened studies.
The following information was extracted from each study: author, trial name, year, drug, dose, control group (placebo or active comparator), MS subtype, sample sizes, trial duration, baseline patient characteristics, CDP in each group by the end of the trial, and p-values (Table 1, also see Supplementary Material for an Excel spreadsheet containing all trial data and accompanying calculations). For trials that did not list a hazard ratio, we calculated the percent inhibition of disability progression (%IDP) as follows:
$\%\text{IDP}=\left(1-\frac{{\hat{p}}_{\text{drug}}}{{\hat{p}}_{\text{placebo}}}\right)\times 100\%$
where ${\hat{p}}_{\text{drug}}$ represents the proportion of patients from the drug group with CDP, and ${\hat{p}}_{\mathrm{placebo}}$ represents the proportion of patients from the comparator group with CDP by the end of the trial. This formula is equivalent to a relative risk reduction, where the ratio between ${\hat{p}}_{\mathrm{drug}}$ and ${\hat{p}}_{\mathrm{placebo}}$ represents the relative risk of disability progression.

We conducted a retrospective cohort study using prospectively collected clinical information from the Swedish MS Registry (SMSreg). All 64 neurology clinics in Sweden contribute MS-specific clinical information to this resource, which is estimated to capture 80% of all cases of MS in the country.^{6 (link)} Registered cases of definite MS with an onset of disease between January 1, 1975, and December 31, 2014, were included, to allow sufficient follow-up time before the study end date of April 15, 2018. Persons with fewer than 2 Expanded Disability Status Scale (EDSS) measurements on record were excluded. Pediatric-onset cases were defined as those whose MS onset occurred before the age of 18 years, in accordance with the definition proposed by the International Pediatric MS Study Group.^{7 (link)}Information in the SMSreg includes sex, date of birth, date of MS onset and diagnosis, date and reason for withdrawal from registry (i.e., emigration or death), clinical course (relapsing-onset or primary progressive), and geographical region of residence.^{6 (link)} The date of MS onset was defined as the date of first recorded clinical manifestation of MS, and the diagnosis was performed by a neurologist based on the prevailing diagnostic criteria at the time of diagnosis.^{8 (link)– (link)11 (link)} The SMSreg is a Quality Register that is routinely assessed for accuracy, such that if a person is found to be misdiagnosed, they are removed from the Registry. Detailed information on disease-modifying therapy (DMT) use (product name, start and stop dates), relapses (date of onset and complete remission [complete clinical recovery within 6 months] or incomplete remission), and EDSS scores were prospectively recorded by the treating neurologist. Three distinct endpoints were analyzed: time to EDSS 3 (moderate disability, though fully ambulatory), EDSS 4 (limited walking ability, but able to walk more than 500 m without aid or rest), and EDSS 6 (ability to walk with unilateral support no more than 100 meters without rest). The local Multiple Sclerosis Severity Score (MSSS)^{12 (link)} was also calculated to compare disease severity at the first recorded EDSS between groups. DMTs were categorized as first- or second-line based on the prescribing guidelines in Sweden. First-line therapies included interferon-β, glatiramer acetate, teriflunomide, and dimethyl fumarate. Second-line therapies included fingolimod, daclizumab, rituximab, mitoxantrone, and natalizumab. Average annualized relapse rates were calculated for individuals in the first 5 years of disease (from MS onset). CSF results are recorded prospectively in the SMSreg, and were assessed for the cases of pediatric-onset MS who were identified as progressive from onset. Follow-up extended from birth or MS onset until the last available EDSS score prior to emigration, death, or the study end date, whichever came first.

We calculated the needed sample size using G*Power 3.1 software [66 (link)]. Experiment 1 investigated whether anti-phase alpha-tACS and in-phase alpha-tACS would induce different behavioral and electrophysiological effects. Based on the medium or large effect sizes reported in previous studies that used NIBS to modulate parietal alpha oscillations and WM [48 (link),50 (link)], a medium effect size (Cohen’s d = 0.5) was assumed. Thus, a sample size of 34 participants was needed to detect a reliable effect with a statistical power of 80% and an alpha probability of 0.05 in a two-tailed paired t-test.
A total of 48 healthy participants between the ages of 18 and 40 completed Experiment 1. All participants were right-handed and reported no metal implants in the brain, no implanted electronic devices, no history of neurological problems or head injury, no current use of psychoactive medication, no history of craniotomy, and no skin sensitivity; the participants were nonpregnant, had normal or corrected-to-normal visual acuity, and were not enrolled in any other NIBS research within 3 months of their study participation. Participants who failed to follow directions or did not understand instructions were removed from the study. All participants were recruited in Hefei, China through advertisements or posters. Eight participants were excluded from the analyses due to poor EEG signals or malfunctions of the tACS stimulator to trigger the intended electrical stimulation. One participant whose alpha activity was too weak for detection and who therefore had to repeat the Baseline Sternberg task 3 times per session was also excluded. The remaining 39 participants (19 females, mean age ± SD:21.1 ± 2.2 years, mean education ± SD:14.7 ± 1.8 years) were included for behavioral and EEG analyses, which meets the sample size requirement.

In Experiment 1, participants attended 3 sessions, 1 for each of the 3 distinct tACS conditions (in-phase tACS, random-phase tACS, or anti-phase tACS) were applied (Fig 3D). The order of tACS conditions was counterbalanced across participants (Fig 3B). The 3 sessions of each participant were all separated by at least 3 days and performed at approximately the same time of the day. The experimental procedures for each session are as follows (Fig 3C).
At the start of each session, participants first completed 32 practice trials of the Sternberg task (Fig 3A). Following this practice, participants performed a total of 300 trials of the Sternberg task divided into 5 sets.
In the first 60 trials (“Baseline”), spontaneous EEG signals were recorded for 2.5 s in each trial, starting from the beginning of a retention subprocess. Following the Baseline trials, the IAF and the threshold were calculated from the Baseline EEG data at the Pz electrode (see more details in S1 Text: “1.2. IAF and threshold determination”). The IAF was used as the subsequent tACS frequency for this session. The threshold was set to restrict the application of tACS to when parietal alpha activity is prevailing to be detected.
Then, participants performed 180 tACS-EEG trials (“Online tACS”) while performing the Sternberg task. In each trial, EEG data at the Pz electrode was monitored continuously once the retention subprocess began. The online phase-corrected tACS was triggered when the amplitude of endogenous alpha oscillations exceeded the threshold twice in a row (see more details in S1 Text: “1.1. The details of online phase-corrected tACS system”). Each tACS application lasted for 0.8 s. Once stimulation was triggered, the EEG recordings stopped to avoid tACS artifacts. When the retention subprocess of the next trial began, EEG recordings restarted and the aforementioned process was again used to determine whether and when tACS was triggered. After Online tACS, participants filled out a tACS sensation questionnaire to assess tACS-induced discomfort (see more details in Blinding section).
Following Online tACS, participants completed the final 60 trials of the Sternberg task, while EEG data were recorded during the retention subprocesses (“Offline tACS”).