Clinical trial NCT01520363
Conditions: Rett Syndrome
Keywords: Rett syndrome RTT MECP2 dextromethorphan DM
Sponsor: Hugo W. Moser Research Institute at Kennedy Krieger, Inc.
Start date: 2012-03-01; Completion date: 2016-10-26
Enrollment: 57 participants; Allocation: RANDOMIZED; Intervention model: PARALLEL

Brief summary:
Dr. Sakkubai Naidu, Principal Investigator, is initiating a double blinded placebo controlled clinical drug trial using dextromethorphan (DM) in Rett Syndrome (RTT), at the Pediatric Clinical Research Unit (PCRU) of the Johns Hopkins Hospital/Kennedy Krieger Institute. Funding source , FDA-00PD

It has been shown that receptors for a certain brain chemical called glutamate, in particular the NMDA type, are increased in the brain of young RTT patients (\<10 years of age). This chemical and its receptors, when in excess, cause harmful over-stimulation of nerve cells in the brain, contributing in part to the seizures, behavioral problems, and learning disabilities in RTT.

The investigators propose to initiate a specific treatment using DM to counter/block the effects of this brain chemical and its excessive receptors to improve the ill effects of increased glutamate/NMDA receptors, because of DM's identified ability to block NMDA receptors. DM is available for human consumption. Infants and children with respiratory infections and cough, as well as non-ketotic hyperglycinemia, are treated with DM, which has been well tolerated.

Detailed description:
The study will last for 3 months and will be limited to MECP2 mutation-positive children, one year - 9.99 years of age. This clinical trial, which is a placebo-controlled study, will randomize patients to the drug or placebo to determine the benefits of DM vs placebo on cognition, behavior, or seizures if present.

Your child will stay twice in the Pediatric Clinical Research Unit (PCRU) at Johns Hopkins ICTR, for 3 days during each admission. The first hospital stay will be for 3 days, before she starts the DM or placebo. The follow-up 3-day hospital stay will be 3 months after she starts taking DM or placebo. There will also be two interim follow up evaluations at 2 weeks and 1 month after she starts taking the DM or placebo consisting of a neurological evaluation, EKG, and blood work, which can take place at your local doctor's office or at Johns Hopkins, and will be paid for by this study. Our research nurse or research associate will contact you at least weekly during the first month, and at least monthly thereafter until the end of the 3-month study.

Arms: arm 1: MECP2 mutation positive subjects randomized to receive DM arm 2: MECP2 positive subjects randomized to the placebo compound
Interventions: intervention 1: dextromethorphan intervention 2: placebo
Intervention descriptions: intervention 1: The DM group will take 5mg/kg/day orally in 2 divided doses 12 hours apart for the 3 month period of the study. The pharmacists will dispense the DM to the study participants. intervention 2: The placebo will be dispensed to equal the volume of DM of 5mg/kg/day. It is taken orally in 2 divided doses 12 hours apart during the study period of 3 months. The Research pharmacist will dispense the placebo to the participants.

Protocol documents:
Prot_SAP_000.pdf: 
Date:  April 12, 2013    
Principal Investigator:  Sakkubai Naidu 
Application Number:  NA_00064949 
 
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Version 3 Dated:   06/2007 
 
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Johns Hopkins Medicine - eForm A 
 
 
 
 Use the section headings to write the eForm A, inserting the appropriate material in each. If a 
section is not applicable, leave heading in and insert N/A. 
 When submitting eForm A (new or revised), enter the date submitted to the field at the top of 
eForm A. 
 
*************************************************************************************************** 
 
 
1. 
Abstract 
a. Provide no more than a one page research abstract briefly stating the problem, the research 
hypothesis, and the importance of the research. 
The overall goal of the study is to counter the effects of increased N-methyl-D-aspartate 
(NMDA)/glutamate receptors in MeCP2-mutation-positive Rett syndrome (RTT) subjects by 
use of a placebo-controlled trial of dextromethorphan (DM), an agent known to block the 
NMDA receptor channels. The drug dose of DM will be 5mg/kg/day as this dose showed 
optimal results in our previous dose-effect study. We anticipate improved cognition and 
temperament, and reduced seizure frequency.  
RTT is a neurodevelopmental disorder with devastating consequences to both brain and 
systemic neurons. Despite a prominent 50% reduction in the number of synapses, postmortem 
brain autoradiographic studies demonstrate a striking and disproportionate increase in the 
number of glutamate/NMDA (N-methyl-D-aspartate) subtype of receptors in the prefrontal 
cortex, especially in younger patients. DM blocks NMDA receptor channels, which improve 
some clinical manifestations of RTT (eg, cognitive and behavioral deficits, seizures) by 
reducing the excitotoxic damage and preventing the degree of intellectual disability over the 
long term. Presently, there is no effective therapy or definitive treatment for RTT, other than 
palliative care, therefore, our overall specific aim in this biologically-based study is to test the 
efficacy of DM vs placebo in RTT to block the disproportionate numbers of glutamate/NMDA 
receptors in the brain and alleviate symptoms. This study holds promise for improved quality of 
life for girls with RTT, by helping to reduce the degree of functional impairment in this 
population. Moreover, this study would lend itself to a mode of therapy for other epileptic 
conditions also associated with glutamatergic excitotoxicity. 
Measurement of cytokines and glutamate in serum and released from peripheral blood 
mononuclear cells (PBMC): Much of the experimental work has been conducted on the Mecp2 
null mouse.  Although the model has provided great insight into the disease, there are distinct 
differences between the murine model and the human disease.  For example, the human disease 
in many is caused by several mutations, and not only the absence of MECP2.  Many mutated 
forms of MECP2 display some functionality (Gonzales ML and LaSalle JM, The role of MeCP2 
in brain development and neurodevelopmental disorders. Current Psych Reports 2010:12:127-
34). Multiple mutations described in children with Rett display varying phenotypes in females.  
The disease phenotype is severe in the male mouse model, however, in the human disease, 
males carrying mutated MECP2 usually are few, not frequently recognized, are extremely ill, 
and therefore not well studied.  
Two studies have been recently published suggesting the involvement of the innate immune 
response in RTT.   In one, hippocampal neurons displayed abnormal dendritic morphology in 
the presence of conditioned media from cultures of Mecp2-null microglia. Glutamate was 


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identified as the mediator causing the damage [2]. (Maezawa, I. and Jin, L. W. (2010) Rett 
syndrome microglia damage dendrites and synapses by the elevated release of glutamate. J 
Neurosci 30, 5346-56).  In the second study, investigators found that Mecp2 null mice that 
received a graft of bone marrow cells from wild-type mice survived longer and displayed 
significant improvements in respiratory function and motor control.  Because the benefits of 
wild-type microglia were diminished by blocking their phagocytic ability, the importance of 
phagocytic activity in RTT was suggested [3] (Derecki, N. C., Cronk, J. C., Lu, Z., Xu, E., 
Abbott, S. B., Guyenet, P. G., Kipnis, J. (2012) Wild-type microglia arrest pathology in a mouse 
model of Rett syndrome. Nature 484, 105-9). To determine the relevance of these findings in 
human monocytes, we developed a model to study Mecp2 deficiency by transducing peripheral 
blood mononuclear cells (PBMC) with lentiviral shRNA against MECP2.   
 
2. 
Objectives (include all primary and secondary objectives)  
Primary outcome: Improve cognition. Cognitive skills will be measured by neuropsychological 
tests (Mullen Scales of Early Learning). 
Secondary outcome: Improvement in behavior will be measured by: a) Vineland Adaptive 
Behavior Scales (VABS); b) behavior and temperament dysregulation will be measured by the 
Ghuman-Folstein Screen for Social Interaction (SSI). 
Exploratory outcome measures:  a) Seizure frequency will be measured by a seizure diary and 
interim evaluations by neurologists. As commonly used anticonvulsants are not known to 
change EEG patterns in RTT patients, those on anticonvulsant medications prescribed by their 
neurologists will continue on the same medications and doses throughout the study;  b) Rett 
Syndrome Behavior Questionnaire (RSBQ); c) Pediatric Quality of Life Inventory (PedsQL 
version 4). d) Measure cytokines and glutamate in serum released from peripheral blood 
mononuclear cells (PBMC) in children with Rett Syndrome and determine whether treating 
children with dextromethorphan modifies the cytokine and glutamate levels.  Studies in Dr. 
Bressler’s laboratory have shown elevated responses in human PBMC made MECP2 deficient 
with lentiviral shRNA against MECP2.  We observed increased expression of glutaminase 
(GLS) mRNA and increased release of glutamate in MECP2 deficient PBMC compared to 
controls (fig 1). We also observed increased expression of TNFα and IL-6 mRNA (not shown).  
These responses were inhibited by drugs that block the NF-κB signaling pathway.   
 
3. 
Background (briefly describe pre-clinical and clinical data, current experience with procedures, 
drug or device, and any other relevant information to justify the research) 
Our investigations in RTT as well as that of others demonstrate elevated brain glutamate and its 
NMDA receptors in children below 10 yrs of age and in the RTT mouse model prior to 7 weeks of 
age. Additionally, our preliminary therapeutic trial shows that DM, which blocks NMDA 
receptors, benefits RTT patients by ameliorating some symptoms and improving quality of life.  In 
stage 2 of RTT (1- 4 years of age) acquired skills are lost, with onset of autistic-like features, 
stereotyped behaviors, and poor hand use accompanied by diffuse slowing and frontocentral spikes 
on EEG.  Mental retardation (MR) and respiratory irregularities in the wake period become evident 
in stages 2 and 3 (5-10 yrs).  In stage 3, patients appear to recover from the autistic tendencies but 
all other symptoms remain, with poor weight gain, gastrointestinal problems, vasomotor instability 
of extremities, and osteopenia, as concomitant findings.  Interventions to reduce some aspects of 
the morbidity and mortality in stages 2 and 3 that could be related to the neuroexcitotoxicity seen 
in Rett syndrome require early intervention.  Neuroexcitotoxic injury, as also shown in cultured 
neurons to elevated glutamate levels by Russell et al. and Maezawa and Jin, needs to be stabilized 


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to prevent progressive brain injury, thus reducing long term effects of mental retardation and 
ancillary deficits. 
The results in Dr Bressler’s experimental studies of PBMC shown in Fig below warrant evaluation 
of the effects of DM treatment as compared to those who are on placebo. 
 
 
 
               
 
Figure 1.  GLS mRNA levels and glutamate release in MeCP2 deficient leukocytes.   
Glutaminase (GLS) mRNA was measured from total RNA isolated from PBMC transduced with 
either the MECP2 shRNA lentiviral vector or control.  GLS mRNA was normalized to GAPDH 
mRNA (A).  Similarly, glutamate released into the media was measured in transduced and control 
cultures (B).  Some cultures were also treated with the NF-κB inhibitors Act and JSH .  The data are 
expressed as a mean of triplicates of a representative experiment ± S.E.M.   * p<0.05, ** p<0.01 
and ***p<0.001 using ANOVA with Dunnetts multiple comparisons post hoc test.     
 
 
4. 
Study Procedures 
a. Study design, including the sequence and timing of study procedures   
(distinguish research procedures from those that are part of routine care). 
Sixty subjects with clinical features of RTT, with a known mutation in the MECP2 gene, will be 
studied in this placebo controlled trial of DM in RTT. We will use a randomization scheme 
instituted by personnel not directly involved with the study subjects. The DM group will take 
5mg/kg/day orally in 2 divided doses 12 hours apart. The pharmacists will dispense the DM or 
placebo to both the in‐ and out‐patient study participants. The study population will consist of 30 
subjects in the placebo group and 30 subjects in the DM group.  We will randomize patients to 
dextromethorphan or placebo using a computer‐generated randomization sequence with varying 
block sizes that is stratified for age (2‐5 years vs. 6‐10 years). Given the moderate sample size, 
using pre‐stratification will further increase the probability for having balanced and comparable 
treatment groups. The statistician will generate the randomization list for the JHH Investigational 
Drug Service. By always keeping the randomization list separate and inaccessible to study 
investigators, we will ensure concealment of random allocation.   
Assessment of treatment efficacy: Subjects will be followed at regular intervals during the study by a 
series of evaluations, as indicated below. All subjects in the study will be followed until the last 
recruited subject has completed 3 months of the trial. In light of the large number of RTT patients 
<10 years of age available for study, we believe we can recruit 60 subjects within the 3-year study 
period.  
All procedures are for research purposes to assess the effectiveness of DM vs. placebo. 
A 
B


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Since DM may be slowly excreted in about 10-20% of the normal population, a pharmacokinetics 
(PK) study will be performed by administering one 2.5mg/kg oral dose of immediate release DM-to 
be given during the first hospital admission (after the baseline blood sample for PK testing is 
obtained) to determine the rate of metabolism of DM. Drug levels will be monitored twice by a 
blood test: a) at peak level (3 hours) and, b) at the lowest level (12 hours).  Should a subject be 
found to be an intermediate or slow metabolizer of DM, she would be excluded from this study 
because a safe dose of DM could not be determined.   The study drug or placebo would not be 
started until after results from the baseline visit PK testing are available to the study team about the 
DM’s PK status of the participant.  Following the PK study, the rapid metabolizers will be included 
in the 3-month trial, and will take DM at a dose of 5mg/kg/day or an equal volume of placebo, 
given in two divided doses, exactly 12 hours apart. At the end of the study the code is broken to 
determine whether DM shows more effectiveness than placebo. 
The test procedures/evaluations/assessments per the study protocol will be performed during two 3-
day inpatient admissions to the Johns Hopkins Pediatric Clinical Research Unit (PCRU). Subjects 
will be admitted as follows: 1) the initial admission will be prior to the initiation of the placebo-
controlled DM trial, and 2) the second admission will be at the end of 3 months of the study. Any 
test result done as part of the study protocol that shows a deviation from normal, is to be repeated, 
as a clinically indicated test.   In addition to the baseline and end of study admissions, all subjects 
will be required to have two interim evaluations at 2 weeks and at 1 month during this study (as 
noted below) either by us in our outpatient clinic or by their local physician, with no more than a 
two-week delay being permitted to obtain the required interim tests. 
Upon discharge from the initial (baseline) PCRU admission, all study participants will be closely 
followed by the research associate or research nurse by at least weekly telephone interviews during 
the first month, and then at least once/month telephone interviews through the end of the 3-month 
study.  
Study Protocol procedures: (all test results/performances will be compared to subjects' baseline 
values): 
1) We will request parents to provide us with medical records or release of information from 
appropriate sources; i.e, MeCp2 gene test report, birth and developmental history, and 
neurological reports. 
2) a)   General physical/neurological examinations; (approximate time allotted is 1 hour);  
b) EKG (due to reports of prolonged QTC interval); (time allotted is ~20 minutes); 
c) Orthostatic blood pressure assessment (due to autonomic dysfunction); (time allotted is ~10 
minutes).  
These tests will be performed before initiation of DM or placebo during the baseline inpatient 
admission, and are to be repeated at the required two interim evaluations at 2 weeks and 1 
month during the trial, and again during the 3-month end of study admission. 
3) Blood tests: 
Initial, baseline admission: a) Routine CBC with differential (2cc); b) comprehensive 
metabolic panel (CMP) and liver function tests (LFTs) (3 cc); c) DM pharmacokinetic assay 
(12cc divided for 3 draws at baseline, peak and lowest level);  d)  For those already getting 
blood drawn for CBC, CMP and DM level, we will collect an additional one cc of blood to 
obtain serum and peripheral blood mononuclear cells in pre treated children. The blood will be 
immediately transferred to Dr. Bressler’s laboratory and processed.  Serum and cells will be 
frozen and assays will be performed when sufficient numbers of samples are collected.  
Cytokines will be measured by ELISA and cellular responses will be examined by flow 
cytometry. 


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Interim evaluations at 2 weeks and 1 month: a) Routine CBC with differential (2cc); b) CMP 
and LFT (3cc); c) DM level (6cc). 
4) End of study (3-month) admission: a) Routine CBC with differential (2cc); b) CMP and LFT 
(3cc); c) DM level (6cc).  d)  For those already getting blood drawn for CBC, CMP and DM 
level, we will collect an additional one cc of blood to obtain serum and peripheral blood 
mononuclear cells in post treated children. The blood will be immediately transferred to Dr. 
Bressler’s laboratory and processed.  Serum and cells will be frozen and assays will be 
performed when sufficient numbers of samples are collected.  Cytokines will be measured by 
ELISA and cellular responses will be examined by flow cytometry.Approximately 2cc blood for 
a serum pregnancy test will be obtained on the first day of admission (takes about 5 minutes) in 
those who are post-menarchal, which will be very few given the younger age of this study 
population (to be obtained before initiation of DM during the baseline admission and again 
during the end of study admission after 3 months).  Parents will be informed about the need and 
rationale (ie, drug effect) for the pregnancy test. If they decline the pregnancy test because of 
any concerns, they will be unable to participate in this study. 
 
5) Neuropsychological testing (approximately 2 - 2 1/2 hours) by a neuropsychologist to assess 
cognitive status (Mullen Scales of Early Learning (MULLEN), Vineland Adaptive Behavior 
Scales (VABS), will be performed during the baseline admission and at the 3-month end of 
study admission. 
6) Neurobehavioral evaluation (approximately 1 hour) by a child psychiatrist to assess behavioral 
abnormalities. Parent will complete behavioral checklists/questionnaires: Ghuman-Folstein 
Screen for Social Interaction (SSI), Rett Syndrome Behavior Questionnaire (RSBQ) upon 
baseline admission and at the 3-month end of study admission. 
7) Nutritional assessment (approximately 45 minutes) for monitoring growth indices (height, 
weight, head circumference, body mass index) and nutritional intake. A 3-day food record will 
be sent to families prior to admission (see Oral Consent form). 
8) Quality of Life questionnaire, the Pediatric Quality of Life Inventory (Peds QL version 4) to 
assess the child's physical, emotional, and social well-being from the perspective of a parent or 
guardian, to be obtained at the baseline and 3-month end of study admissions. 
9) We will assess compliance including drug and/or placebo intake or compliance with the study 
protocol including the two required interim evaluations by at least weekly telephone intake 
phone calls by our research nurse or research associate during the first month of the study, and 
by at least monthly telephone intake phone calls until the end of the 3-month study.  
10) After hours pediatric resident coverage in the PCRU will be provided by the Neill team, the 
hospital’s standard procedure. 
11) De-identified information will be shared with our research collaborators. 
 
  
 
b. Study duration and number of study visits required of research participants. 
We anticipate to complete the study within 3 years. The test procedures as part of the study 
protocol will be performed during two 3-day inpatient admissions to the pediatric clinical 
research unit (PCRU) in the Johns Hopkins Institute for Clinical and Translations Research 
(ICTR). Subjects will be admitted to the PCRU twice to assess changes in primary, secondary, 
and exploratory outcome variables. The baseline admission will be prior to initiation of the 3-
month study and the second admission will be after 3 months of the trial.  


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In addition, subjects will have two interim evaluations required at 2 weeks and 1 month during 
this study to be done either in our outpatient Clinic or by their local physician. The neurological 
evaluation will take about one half hour, the EKG will take about 20 minutes, and the blood 
draw will take about 15 minutes. 
 
c. Blinding, including justification for blinding or not blinding the trial, if applicable. 
The study is a double blind placebo-controlled drug trial to determine the effect of DM 
(5mg/kg/day) versus placebo. 
 
d. Justification of why participants will not receive routine care or will have current therapy 
stopped.  N/A 
 
e. Justification for inclusion of a placebo or non-treatment group. 
The previous dose response study was considered by the FDA to be biased as all participants 
knew the dose of the medication; therefore, the FDA suggested a placebo controlled trial. Also 
the previous study has shown no side effects on any of the doses including the highest dose of 
5mg/kg/day in 2 divided doses of DM in RTT subjects of similar ages. 
 
f. Definition of treatment failure or participant removal criteria. 
The drug or placebo will be discontinued and the subject will be removed from the study if 
severe side effects occur, such as type-1 diabetes, allergic skin rash, agitation, nystagmus, 
persistent nausea, vomiting, increased liver enzymes, slurred speech, ataxia, drowsiness, fatigue, 
dystonia, or urinary retention; or, if any of the blood parameters or EKG being assessed are 
found to be abnormal.  Subjects would be removed from the study if parent shows poor 
compliance including drug and/or placebo intake or compliance with the study protocol 
including the two required interim evaluations. 
Following discontinuation for reasons unrelated to DM/placebo such as severe intercurrent 
illness that is not uncommon in RTT, we would consider restarting the trial of DM/placebo once 
the subject fully recovers and returns to baseline. Our plan would entail establishing a 3-month 
limit wherein no baseline evaluations would be repeated when restarting any subject on DM 
following discontinuation.  However, if the time of recovery and return to baseline is more than 
3 months, then we would repeat baseline evaluations, except the pharmacokinetics of DM-
which would remain unchanged. 
 
g. Description of what happens to participants receiving therapy when study ends or if a 
participant’s participation in the study ends prematurely. 
Clinical follow up will continue until the last subject has completed the 3-month study. Subjects 
will be followed clinically until the entire study period ends, even if a subject's participation in 
the study is ended prematurely for reasons such as: 1) If the family decides to withdraw from the 
study; 2) emergence of other diseases that may interfere with interpretation of test results; 3) 
severe intercurrent illness that is not uncommon in RTT; 4) if severe side effects occur, such as 
those noted below; 5) having more than a 2-week lapse in obtaining the required interim 
evaluations/labs; 6) not following the study protocol. 
 
 
5. 
Inclusion/Exclusion Criteria 


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Inclusion criteria: 1) those with classic or atypical RTT who have a proven mutation in the MECP2 
gene; 2) subjects must be between 2 years - 9.99 years of age.  
Exclusion criteria: 1) those without an established mutation in the MECP2 gene; 2) those with 
mutations in the MECP2 gene but who have had brain resection or surgical intervention; for 
example, tumor, hydrocephalus, severe head trauma; or, an associated severe medical illnesses 
such as vasculopathies, malignancies, diabetes, thyroid dysfunction, etc; 3) those on medications 
that could  interact with DM, e.g. MAO inhibitors, SSRI, sibutramine etc. to avoid a serotonin 
syndrome; quinidine and drugs metabolized by the CYP450 isoform CYP2D6 (e.g. amiodarone, 
haloperidol, propfenone, thioridazine); 4) those proven to be intermediate or slow metabolizers of 
DM; 5) those with reported adverse reactions to DM; 6) those whose pregnancy test is positive; 7) 
those showing poor compliance with any aspect of the study; 8) foster children. 
 
6. 
Drugs/ Substances/ Devices 
a. The rationale for choosing the drug and dose or for choosing the device to be used. 
DM blocks NMDA/glutamate receptors, which are markedly increased in younger RTT patients 
and are hypothesized to cause excitotoxic epileptic encephalopathy. 
b. Justification and safety information if FDA approved drugs will be administered for non-FDA 
approved indications or if doses or routes of administration or participant populations are 
changed.  
Blocking NMDA receptors will prevent neuroexcitotoxic injury to brains, as in non-ketotic 
hyperglycinemia, where it has been given to neonates in a fairly high dose (5-35mg/kg), which 
was well-tolerated. 
c. Justification and safety information if non-FDA approved drugs without an IND will be 
administered. N/A 
 
7.  
Study Statistics 
a. Primary outcome variable. Improvement in cognition. 
b. Secondary outcome variables. Improvement in behavior. 
Exploratory outcome variables: Reduced seizure frequency; improvement in the Quality of Life 
and Rett Syndrome Behavior questionnaires. 
c. Statistical plan including sample size justification and interim data analysis. 
 
The data will be analyzed when all 60 participants (30 subjects in the placebo group and 30 
subjects in the DM group) have completed the 3-month the trial.  
Neuropsychological measures for Mullen and VABS: Subjects will be assigned to intervention 
in a randomized manner as described in randomization. The neuropsychological measures to 
establish relative cognitive and adaptive competence of the 2 groups to be comparable, age 
equivalent scores on the Mullen and VABS measures will be compared between groups using 
2x2 repeated measures analysis of variance (ANOVA) with the between subjects factor being 
drug or placebo and within subjects factor being time. Changes in cognitive measures (Mullen 
and VABS) will be correlated with the behavior measures and seizure frequency.  
 
We based our sample size on the primary outcome, which are the receptive language age 
equivalent scores on the Mullen scale. There is no established minimal important difference for 
the Mullen score that is widely accepted and would provide a reasonable effect estimate for 
sample size calculation. However, a distribution-based estimate of the minimal important 
difference can be derived from the standard errors of measurement (SEM) that have been 


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reported for the Mullen subscales (chapter 6 of the Mullen scale) and 1 SEM provides an 
accepted approximation of the minimal important difference. To detect a 4 point difference (1 
SEM) in the receptive language age equivalent scores on the Mullen scale between the groups 
and assuming a standard deviation of 5 points (based on our pilot data) we need a total sample 
size (both groups) of 50 patients at a significance level of 0.05 (two-sided) and a power of 80%. 
Assuming a dropout rate of around 15% the required sample size increases to 60 patients.  
 
Sample size calculation.  Measurement of cytokines and glutamate in serum and released from 
peripheral blood mononuclear cells: We estimate that 12 children in each group (placebo and 
drug treated) will be needed using an alpha=0.05 and a power=0.8.     
 
 
We will randomize patients to dextromethorphan or placebo using a computer-generated 
randomization sequence with varying block sizes that is stratified for age (2-5 years vs. 6-10 
years). Given the moderate sample size, using pre-stratification will further increase the 
probability for having balanced and comparable treatment groups. A Johns Hopkins statistician 
will generate the randomization lists. By always keeping the randomization list separate and 
inaccessible for study investigators, we will ensure concealment of random allocation. 
 
d. Early stopping rules. None. 
 
8. Risks 
a. Medical risks, listing all procedures, their major and minor risks and expected frequency. 
Dextromethorphan:  Potential major risks include reversible type-1 diabetes, and allergic skin 
rash. Potential minor risks include lightheadedness, nystagmus, agitation, persistent nausea 
and/or vomiting, increased liver enzymes, and slurred speech. Dextromethorphan may be 
associated with mild and infrequent occurrence of dizziness, drowsiness, urinary retention, 
ataxia, fatigue, and dystonia.   
Infrequently, patients on other medications including antipsychotics, lithium, SSRI’s, MAO 
inhibitors may experience psychosis, serotonin syndrome, and hyperthermia. Long-term studies 
have not been performed with DM, and there may be unknown long-term side effects. 
Blood draw: The health risk of venipuncture (blood draw) is negligible.  There is minimal 
discomfort from the needle during insertion, with a slight risk of bleeding, bruising, or infection 
following the blood draw. Subjects may be fearful and have discomfort during the blood draw.  
Blood pressure monitor:  Minimal discomfort may be experienced when the cuff is in place 
around the child’s arm. 
Pregnancy Test and Result: In post-menarchal subjects (which would be very few given the 
younger age of this study population), a serum pregnancy test will be performed on the first day 
of admission. Parents will be informed about the need and rationale (ie, drug effect) for the 
pregnancy test. If they decline the pregnancy test because of any concerns, they will be unable 
to participate in this study. If they agree, the risk of learning that their child’s test is positive and 
subsequent removal from the study may cause emotional distress to the parents and family. A 
positive result will be discussed with the family with the necessary level of sensitivity. 
EKG: Rarely, there may be a topical skin reaction to the electrode paste or slight discomfort 
during placement of electrodes. 
Behavioral and Psychological evaluations: During the intake interviews used to gather 
information for the questionnaires or scales during these evaluations, parents may choose not to 


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answer any question(s) that may cause them discomfort, which will be handled empathetically 
and compassionately. 
Nutrition Assessment: During the interview with the nutritionist to gather information about the 
subjects’ diet, food preferences, food allergies, etc., some question(s) may cause parents 
discomfort. Slight discomfort may occur when measuring body mass, head, weight, height. 
Interview Discomfort: During interviews to obtain information for the intake/clinical 
questionnaires, the parent(s) may decline to answer any question that may cause them 
discomfort, which will be handled empathetically and compassionately. 
Risk of Disclosure of Information/Loss of Privacy:  There is a risk of disclosure of 
information/loss of privacy; however, many steps are taken to minimize this risk as described 
below.  
Disruption to work or school schedules: Parents or participants may undergo disruption to their 
work and/or school schedules when committing the necessary time to undergo the two 3-day 
inpatient admissions and the  two required outpatient interim evaluations during the 3-month 
drug trial. 
 
b. Steps taken to minimize the risks. 
All subjects will be by handled by experienced staff at both Johns Hopkins and the Kennedy 
Krieger Institute, who are well qualified to handle and address any discomfort or concerns. 
Subjects are carefully screened and monitored before and after all study procedures. Also, 
during the interim period between the initial and 3-month follow-up admissions, subject status is 
assessed by at least weekly telephone calls by the PI, research associate, or research nurse, 
during the first month, and at least once/month thereafter until the end of this 3-month drug trial. 
Moreover, interim evaluations performed by us or by subjects’ local physicians at 2 weeks and 1 
month will identify any abnormality(ies) during the drug trial, and any test showing a deviation 
from normal will be repeated as a clinically-indicated test that is not paid for by this study.   
In addition, the following additional steps will be taken to minimize the risks:  
Dextromethorphan (DM):  Patients on known drugs that could interact with dextromethorphan, 
including those listed above, are excluded from participating in this study (see Exclusion 
Criteria). Withholding DM or placebo reverses the symptoms without residual effects.  In 
addition, our research pharmacist provides each participant a Dextromethorphan Patient 
Information Sheet, explains to parents the administration and dosage at discharge when provided 
with the DM or placebo, and provides a contact phone number if they have any questions about 
DM.   
Blood draw: Experienced personnel will draw the blood. Bleeding, bruising, or infection from 
needle insertion can be readily treated. Our staff is well qualified to address possible fear or 
discomfort during the blood draw. 
Blood pressure monitor: Experienced personnel will place the cuff around the arm. 
Pregnancy Precautions: In those very few post-menarchal subjects, a serum pregnancy test will 
be performed on the first day of admission; if positive, the subject will be removed from the 
study.  
EKG: Any topical skin reaction can be readily treated. 
Behavioral and Psychological evaluations: Parents are informed prior to the interviews that they 
can choose not to answer any questions that may make them feel uncomfortable or upset. The 
psychiatrist and the psychologist are well experienced, empathetic, and compassionate during 
the interviews. 


Date:  April 12, 2013    
Principal Investigator:  Sakkubai Naidu 
Application Number:  NA_00064949 
 
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Version 3 Dated:   06/2007 
 
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Nutrition Assessment: During the interview, parents can choose not to answer any question(s) 
that may make them feel uncomfortable or upset. An experienced nutritionist in the PCRU will 
perform the body measurements.   
Interview discomfort: Parents are informed prior to the interviews that they can choose not to 
answer any questions that may make them feel uncomfortable or upset. The interviewers are 
well experienced, empathetic and compassionate during the interviews. 
Risk of disclosure of information/loss of privacy:  Many steps are taken to prevent the risk of 
disclosure of information/loss of privacy, such as deidentifying/coding information and samples; 
storing identifying data separate from deidentified data in locked offices with limited/restricted 
access; password-protected and access-restricted databases.  Release of information is provided 
only with appropriate signed authorization by parent. The blood samples are for research 
purposes only, and not for distribution for sale or for selling any products derived from the 
blood. 
Time commitment:  We will be as flexible as possible with scheduling the inpatient admissions 
to accommodate the family’s schedule. 
 
c. Plan for reporting unanticipated problems or study deviations. 
The DSMB, IRB, KKI’s RCO, JHH-ICTR, and the FDA, will be immediately notified of 
adverse effects by a Problem/Event Report Form completed by the PI. 
The Data Safety Monitoring Board (DSMB), IRB, KKI’s Research Compliance Office, JHH-
ICTR, and the FDA, will be immediately notified of protocol events by an Problem/ Event 
Report Form completed by the PI.  
The DSMB, which is updated every 2 months by the PI with a progress report, will be chaired 
by Dr. Bruce Shapiro, Professor, Department of Pediatrics, JHMI and Vice President of KKI 
Training Program; and will include Dr.  Ali Fatemi, Asst. Professor of Neurology, JHMI; Dr. 
Harvey Singer, Professor of Neurology, Johns Hopkins University School of Medicine. They 
will meet with the PI and Research staff at least annually to discuss progress and averse events. 
The DSMB will assess "reasonable safety" and make changes if and when appropriate upon 
notification of adverse effects by the PI. The DSMB will make recommendations for protocol 
and/or consent modifications, suspension, or early termination of the trial. The PI will then 
inform the IRB and FDA of any recommended changes or suggestions.  The DSMB will not 
have contact with patients or families. 
 
d. Legal risks such as the risks that would be associated with breach of confidentiality. 
There are very few to no legal risks associated with breach of confidentiality, as all information 
is shared only between researchers participating in this study, parent(s), and those authorized by 
them. Information is deidentified when shared with other research collaborators. 
 
e. Financial risks to the participants. 
This study has sponsorship from the FDA # 004247-01 and by the JHH-ICTR. Monies are given 
to the Institute and not to investigators.   
Both the initial and follow-up 3-day hospital admissions to the PCRU, the subject’s meals, 
including all proposed test procedures/evaluations performed during those two inpatient 
admissions as part of the study protocol are paid for by this research study.  In addition, the 
costs of the required two interim maintenance evaluations (ie, neurological eval, EKG, DM 
levels, CBC, CMP (electrolytes/ LFTs) to be done at 2 weeks and 1 month are paid for by this 
research study.  


Date:  April 12, 2013    
Principal Investigator:  Sakkubai Naidu 
Application Number:  NA_00064949 
 
JHMIRB eFormA  01 
Version 3 Dated:   06/2007 
 
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If particpants live more than 5 hours driving distance fr Johns Hopkins, the study will reimburse 
round trip travel costs (up to $500 for the subject and up to $500 for one parent  (up to a total of 
$1,000 per visit)).  
For those driving, reimbursment will be processed after discharge from the study, per Federal 
reimbursement rate for round trip mileage. 
Not paid for by us: Any clinical/laboratory assessments required outside of this study’s 
protocol, or those tests to be repeated as clinically-indicated tests.   
 
 
9. 
Benefits 
a. 
Description of the probable benefits for the participant and for society. 
Participant: There are no individual medical benefits for participating in this study.  
Dextromethorphan may improve cognition and behavior or lessen or diminish seizures. The 
measurement of cytokines and glutamate in serum and released from peripheral blood 
mononuclear cells will determine whether treating children with dextromethorphan modifies 
the cytokine and glutamate levels, and reflect this process in brain.   In addition, since the 
subject will be evaluated and followed  by a multidisciplinary team who will address the 
associated neurological deficits that occur in RTT, the family will be advised on current 
treatment(s) available for such impairments, and would be informed in the future should 
new therapeutic interventions become available.  All tests and evaluations as part of the 
research protocol are performed free of charge by experienced professionals involved in the 
study.  
Society: Results of diagnostic test procedures/evaluations may provide understanding of the 
biological basis of RTT. Understanding the neurobiology of RTT will be valuable to other 
mental retardation syndromes such as autism and Fragile-X and, thus, help individuals 
suffering with these disorders as well. We are expected to publish results of this study in the 
medical literature to be available to the general public, so that larger populations of RTT 
patients may benefit if favorable results are noted, or avoid DM use in future if no efficacy 
is proven. 
 
10. Payment and Remuneration 
a. 
Detail compensation for participants including possible total compensation, proposed bonus, 
and any proposed reductions or penalties for not completing the protocol.  
None 
11. Costs 
a. 
Detail costs of study procedure(s) or drug (s) or substance(s) to participants and identify 
who will pay for them. 
The study pays for the cost of all test procedures/consultations/evaluations per the Study 
Protocol performed during the initial and follow-up 3-day inpatient admissions to JHH-
PCRU (required prior to initiating the drug trial and after 3 months of the study), as well as 
the cost of staying in the hospital during the study.  
The cost of  two required interim maintenance evaluations (ie, neurological eval, EKG, DM 
levels, CBC/CMP (electrolytes/ LFTs) at 2 weeks and 1  month  will be covered by this 
study.   
Dextromethorphan or placebo, in the assigned dosage, is provided to the subjects at no cost 
during this 3-month trial.   


Date:  April 12, 2013    
Principal Investigator:  Sakkubai Naidu 
Application Number:  NA_00064949 
 
JHMIRB eFormA  01 
Version 3 Dated:   06/2007 
 
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Travel expenses for the subject (up to $500 maximum) and one parent (up to $500 
maximum) for up to a total of $1000 per visit to the JHH-PCRU is also reimbursed by this 
study.   
Not paid for by this study:  Any test result showing  a deviation from normal will be 
repeated as a clinically indicated test, the cost of which is not covered by this study.   
Any fee-for-service costs of clinical consultations performed outside of this research study 
are the financial responsibility of the subject’s parent. Before additional charges are 
incurred, the parent will be informed of the approximate fee-for-service cost.