1. Update on Treatment of Myasthenia Gravis
Update on Treatment of Myasthenia Gravis KUMC Neurology Grand Rounds 07/29/2016
Richard J. Barohn, M.D.
Chair, Department of Neurology Gertrude and Dewey Ziegler Professor of Neurology
University Distinguished Professor
Vice Chancellor for Research
University of Kansas Medical Center
Kansas City, KS
Dr. Barohn has received consulting fees from NuFactor and Grifols. He has received research grants from ALSA, Biomarin, Eli Lilly, FDA/OPD, MDA, NIH, Novartis, PCORI, PTC, Sanofi/Genzyme, and Sarepta

2. Treatments for Myasthenia Gravis
DECADES INTRODUCED
1930s: Physostigmine & neostigmine
1930s & 40s: Thymectomy
1950s: Mechanical ventilation, edrophonium chloride & pyridostigmine
1960s: Corticosteroids, plasmapheresis
1960s & 70s: Azathioprine
1980s: Cyclosporine
1980s & 90s: Intravenous immune globulin
1990s & 2000s: Mycophenolate mofetil

3. Myasthenia Gravis Mortality: Prior to 1960: >30%-very grave!
Now: < 1%
Due to Mech Vent and Steroids & other Rx
We now expect most patients to improve and some to go into remission

4. Treatment of Myasthenia Gravis Typical Time to Clinical Effect After Initiating Therapy
Edrophonium
1-2 minutes
Pyridostigmine
10-15 minutes
Plasmapheresis
1-14 days
IVIg
1-4 weeks
Prednisone
2-8 weeks
Mycophenolate
2-6 months
Methotrexate
Cyclosporine
Azathioprine
3-18 months
Thymectomy
Several months to several years

5. Annual Cost of Therapy
Intervention
Regimen
Cost
Pyridostigmine
60 mg tid
$1,000
Prednisone
20 mg qod
$25*
Azathioprine
150 mg qd
$2,200
Mycophenolate
1000 mg bid
$6,500
Cyclosporine
150 mg bid
$6,800
Methotrexate
20 mg/week
$400
IVIg
12 gm/kg total dose
$83,000-$98,000
Plasma exchange
36 exchanges
$40,000
* $1,200 annual cost of calcium/Vit D/GI prophylaxis/bisphosphonate

6. Published Studies on Therapy for MG
Most have been non-controlled,
non-randomized, non-blinded
Many simply observational/anecdotal
Rare controlled, randomized, blinded trials
Note: All Rx meds for MG are “off- label” re FDA except pyridostigmine

7. MG Rx: Controlled, Randomized Trials
1. Mount 1964 – ACTH vs. placebo
2. Howard 1976 – Alt day pred vs. placebo*
3. Tindall 1987 – CSA vs. placebo/virgin pts*
4. Tindall 1993 – CSA vs. placebo/IS pts*
5. Gajdos 1997 – PE vs. IVIg
6. Lindberg 1998 – Pulse methylpred vs. placebo*
7. Palace 1998 – Aza/pred vs. aza/placebo*
8. Wolfe 2002 – IVIg vs. placebo*
9. Meriggioli 2003 – MM vs. placebo*
10. Gajdos 2005 – IVIg-2 doses*
11. Nagane 2005 – Tacrolimus vs. placebo
12. Sanders/MSG 2007 – MM vs. placebo*
13. Aspreva-unpublished – MM vs. placebo*
Zinman 2007 – IVIg vs. placebo*
Soliven 2008 – Terbutaline vs. placebo*
Barth 2011: IVIg vs. PE*
Heckmann 2011: MTX vs. Aza*
Howard 2013: Eculizumab vs placebo
Pasnoor 2016: MTX vs. placebo*
Wolfe 2016 – Thymectomy
Howard 2016 – Eculizamab vs placebo Phase 3* (? Pos or Neg)
* Blinded
Black Bold-Positive trials

8. Quantitative MG Score
TEST ITEMS WEAKNESS
NONE
MILD
MODERATE
SEVERE
SCORE
Grade 1 2 3
Double vision (lateral gaze) Sec.
>60
11-60
1-20
Spontaneous
Ptosis (upward gaze) Sec.
1-10
Facial Muscles
Normal lid closure
Complete, weak, some resistance
Complete, without resistance
Incomplete
Swallowing 4oz water (1/2 cup)
Normal
Minimal coughing or throat clearing
Severe coughing/choking or nasal regurgitation
Cannot swallow (test not attempted)
Head, lifted (45◦, supine) Sec.
>120
>30-120
>0-30
Right arm outstretched (90◦ sitting) Sec.
>240
>90-240
>10-90
0-10
Left arm outstretched (90◦ sitting) Sec.
Speech following counting aloud from 1-50 (onset of dysarthria)
None at #50
Dysarthria at #30-49
Dysarthria at #10-29
Dysarthria at #9
Right leg outstretched (45◦ supine) Sec.
>100
31-100
1-30
Left leg outstretched (45◦ supine) Sec.
Vital capacity (1): male
female
>3.5
>2.5
>
>
>
>
<1.5
<1.2
Rt hand grip (KgW): male
Female
>45
>31
>15-45
>10-30
5-15
5-10
<5
Left hand grip (KgW): male
>35
>25
>15-35
>10-25
Total QMG Score: ____________________
Barohn RJ, McIntire D, Herbelin L, Wolfe GI, Nations S, Bryan WW. Ann NY Acad Sci 1998;841:769-72

9. MG-ADL
Grade 1 2 3
Score
Talking
Normal
Intermittent slurring or nasal speech
Constant slurring or nasal, but can be understood
Difficult to understand speech
Chewing
Fatigue with solid food
Fatigue with soft food
Gastric tube
Swallowing
Rare episode of choking
Frequent choking necessitating changes in diet
Breathing
Shortness of breath with exertion
Shortness of breath at rest
Ventilator dependence
Impairment of ability to brush teeth or comb hair
None
Extra effort, but no rest periods needed
Rest periods needed
Cannot do one of these functions
Impairment of ability to arise from a chair
Mild, sometimes uses arms
Moderate, always uses arms
Severe, requires assistance
Double vision
Occurs, but not daily
Daily, but not constant
Constant
Eyelid droop
Total Score:
Wolfe GI, Herbelin L, Nations SP, Foster B, Bryan WW, Barohn RJ. Neurology 1999;52(7):1487-9

10. Pyridostigmine (Mestinon)
1st line Rx for MG
Don’t expect or use too much
60 mg TID - QID
If need more than this, immunosuppressive Rx needed
Generic now available
Avoid time-release form
Anticholinergic meds useful for GI side effects:
Hyoscyamine sulfate mg (Levsin/Anaspaz)
No RCT of pyridostigmine in MG!

11. Corticosteroid Treatment for MG
Mechanism: inhibition NF-κB, Dec cytokines
Immune supp
1st line Rx for MG since 1970s
Improvement begins in 2-4 weeks
Maximum benefit in ~ 6 months
Transient worsening occurs in 50% of pts during first week
“Remission” is often steroid dependent
No RCT of prednisone in MG!

12. Prednisone Rx for MG High Dose 60 to 100 mg/day x 2 weeks
Then 60 to 100 mg qod until much better
Then taper 5 mg q 2 wks
Requires initial inpatient admission
Low / Slow Approach
Seybold & Drachman 1974
Gradual increase to avoid initial worsening
10 mg/day; increase by 10 mg q 5-7 days
Then switch to qod
In-between Approach
Mycophenolate trial protocol
Pred 20 mg/day

13. Azathioprine (Imuran) Rx for MG
Purine analog - blocks DNA/RNA synthesis and cell proliferation
Response is slow - up to 18 months
Dose: Begin 50 mg/day x 1 week, Then, 2-3 mg/kg/day
Typical dose 150 mg/day (single dose)
Toxicity
Systemic “flu-like” reaction
Leukopenia
Hepatotoxicity
? √ for TPMP def
Monthly CBC/LFT’s
Palace et al 1998
p =0.02 at 24 mo
placebo
√ pt after
AZA
High dropout (34 to 16)) takes at least a year to have an effect

14. Cyclosporine in MG Selective/reversible on T-cells
Inhibit IL-2 and interferon γ
Inhibits cytotoxic/express supp Ts
CSA Effective in non-immunosuppressed MG
20 patients
CSA Effective in Steroid-Dep MG
39 patients
QMG - Primary End-Point
In 1993 Study:
Mean Dec QMG 3.5 in CSA
Mean Dec QMG 0 in Placebo
Sandoz industry study: results never released
Tindall et al 1987 & 1993

15. Cyclosporine
Dose: 3-6 mg/kg/day in divided dose - b.i.d. Gelatin capsules (25 or 100 mg) or solution (100 mg/ml) Precautions: Monitor CSA levels - maintain trough level < 300 ng/ml Monitor creatinine/BUN/LFTs, BP. Maintain serum creat no more than 30% above baseline; do not exceed 50% Patients with renal impairment or hypertension require careful monitoring

16. Mycophenolate Mofetil Rand/Control Trials in MG
Sanders & colleagues (MSG Neurology 2008;71:394)
Investigator initiated funded by FDA-ODG
Must be AChR-Ab pos
No prior IS Rx
2.5 gm MM vs. plac
All placed on pred 20
1o – QMG 3 mos
2o – MMT, MG-ADL
AChR-Ab, SFEMG
80 subjects
Aspreva sponsored-138 subjects (Sanders et al Neurol 2008;71:400)
Can already be on prednisone
9 month trial
RESULTS FOR BOTH:
NO SIGNIFICANT DIFFERENCE!

17. Mycophenolate Mofetil Rand/Control Trials Why Negative?
Drug does not work
Prednisone improved all pts and masked MM effect
Studies were not long enough
Endpoints were not good enough
Non-homogenous populations enrolled

18. Mycophenolate Mofetil
Dosing:
500 mg bid; increase to 2.5 to 3.0 gm per day (bid dosing).
Comes in 250 mg and 500 mg pills
Monitor CBC

19. Intravenous Immunoglobulin (IVIg)
Polyvalent antibody from pooled plasma from donors.
Possible mechanisms of action:
Fc receptor blockade
Block autoantibody binding in target tissues
Anti-idiotypic antibody effect
Suppresses formation of autoantibodies
Complement absorption
Enhancement of suppressor T cells

20. Lessons: Make lemonade out of lemons – publish neg data – use outcome
Some things you have no control over

21. IV Immunoglobulin in Patients with Myasthenia Gravis
51 pts IVIg vs. placebo
QMG: Sig dif at day 14 (p=0.047)
Persisted at day 28
Change in
IVIg: -2.54
Placebo: -0.89
Post intervention status at day 14
IVIg imp 25%
Placebo imp 6%
RNS/SFEMG-no sig diff
Meriggioli editorial:
Getting enough “bang for the buck”
Zinman, Eduardo, Bril Neurology 2007; 68:

22. IVIg Rx in Neuromuscular Disease Dosing
Induction Dose: 2 gm/kg
Either: 0.4 gm/kg x 5 days or
0.6 / 0.7 / 0.7 gm/kg over 3 days or
1.0 gm/kg x 2 days
Maintenance Dose (For Chronic Diseases)
0.4 to 1.0 gm/kg every 3 to 4 weeks
But may need infusion q 2 weeks or only q 8 weeks

23. Comparison of IVIg & Plex in MG Barth, et al Neurology 2011;76
84 pts to IVIg 1g/kg/d x 2 days
Or PE x 5
QMG > 10.5 and “worsening”
Improved: 69% IVIg and 65% PE
Conc: IVIg & PE both effective Rx

24. Level of evidence for IVlg in MG:
IVig is probably effective for MG and should be considered; Level B.
Patwa HS, Chaudhry V, et al. Neurology 2012; 78:

25. Plasmapheresis
Directly removes humoral factors such as autoantibodies, immune complexes, complement and other nonspecific inflammatory mediators
Remove 3-6 liters of plasma over several hours. Replace with albumin or purified protein fraction (PPF).
Indications for MG:
crises
pre-thymectomy
severe MG (not in crises) when initiating or increasing oral immunosuppressive drugs
chronic Rx

26. Neurology 2011;76:294-300 Pheresis for MG: Recommendation:
Level U (Unknown)
Neurology 2011;76:

27. MG Crises Rx Caveats Begin plasmapheresis ASAP Minimum of 5 exchanges
Increase steroids to high dose
Solumedrol 60 to 100 mg/IV/Day
Stop pyridostigmine
Usually on ventilation at least 5 to 7 days

28. Thymectomy Rx for MG Perlo, et al 1971
Thymectomy – 267 pts
Complete remission – 34%
Improvement – 41%
Non-thymectomy – 417 pts
Complete remission – 17%
Improvement – 11%
Time to remission in thymectomy pts
25% 1st yr
40% 2nd yr
55% 3rd yr

29. A Treatment Carol: Thymectomy Revisited
Michael P. McQuillen, M.D. and Mary G. Leone, M.D. Neurology 1977; 12:1103
Remission Rate:
Nonsurgical Therapy
Author n
Percent
Kennedy and Moersch 87 31
Grob
202 23
Simpson 99 16
Oosterhuis
180
Perlo and Associates
417 17
Overall
985 24
Remission Rate:
Surgical Therapy
Author n
Percent
Kennedy and Moersch
258 21
Perlo and Associates 73 23
Mulder and Associates 99 16
Emeryk and Strugalska
180 31
Patatestas and Associates
417 17
Overall
985 24 .

30. Guest editorial A Treatment Carol; Thymectomy Revisited
Random allocation to surgery or not, in a population homogeneous for variables presumed to be important - age, sex, and duration and severity of disease – should be the most valid way to frame that answer. Such a method would not prevent participating physicians from treating their patients with their best possible judgement in all respects save surgery. If the group denied thymectony then begins to number in its ranks many patients needing corticosteroids for advancing disease, the effect of thymectomy in precluding serous disease will have become obvious. If not, it may be time to cook a different therapeutic goose for myasthenia. Michael P. McQuillen, M.D. and Mary G. Leone, M.D. Neurology 1977; 12:1103 – 1106.

31. Indication for the thymectomy in myasthenia gravis. Douglas J
Indication for the thymectomy in myasthenia gravis Douglas J. Lanska, MD, MS
Article abstract- Fifty-six board-certified neurologists with interest and expertise in myasthenia completed a survey of indications for thymectomy in myasthenia gravis. Thymectomy was advocated for virtually all patients with thymoma, for a variable subset of patients with generalized myasthenia without thymoma, and occasionally for selected patients with disabling ocular myasthenia. Neurology 1990;40:

32. .
11 of 56 Neurologist on the MGF Medical Advisory Board expressed “severe reservation about the efficacy of the procedure” Only 3 individuals advocated thymectomy without reservation” (for generalized MG without thymoma) Lanska DJ, Neurology 1990;40:1828

33. MY GRANTS
MYasthenia Gravis RaNdomized Thymectomy Study Richard Barohn M.D. Presented at MGFA scientific session Chicago 1991

34. MY GRANTS Patient Selection Generalized or bulbar MG
Diagnosed within 6 mos
Ages 18-50
Elevated ACHR-AB
Patients randomized to:
Medical therapy alone
Thymectomy – pts may also be on medical therapy as needed
MY GRANTS

35. MY GRANTS Randomization and Follow-up
Randomization will occur for 3 years Follow-up will be for 5 years Therefore, study could take as long as 8 years.

36. MY GRANTS Blinded Investigator
Not from institute where patient is enrolled
Will be an investigator from a nearby study center
Will have two visits per year to evaluate all enrolled patients
Turtle-neck tops required

37. MY GRANTS Outcome Primary outcome:
Number of patients in clinical remission
(grade 0)
Secondary outcomes:
Number of patients who have improved on
MG grade
Quantitative MRC/QMG/ADL scores

38. MY GRANTS Sample Size/Statistics
If: medical remission = 25% Surgical remission = 40% If p = 0.05 and power = 90% Then: 175 patients in each group

40. Thymectomy Practice Parameter Gronseth and Barohn, Neurology 2000
27 Class II studies
non-random, non-prospective
Surg vs. no-surg
RESULTS: THY pts more likely to do better
RR med free rem 2.1 higher for THY
RR asymp 1.6 higher for THY
RR imp 1.7 higher for THY
PROB: confounding variables:
THYM pts younger, female, more severe
non-random and non-std outcomes
REC – RC trial

41. Randomized Blinded Trial of Thymectomy for MG
Newsom-Davis, Wolfe, Cutter, Kaminski
Randomized/controlled NIH trial
REQ – gen, AChR Ab+
All pts go on prednisone
All get transternal thymectomy
Blinded evaluations
OUTCOME: Pred dose and QMG at 3 yrs complicated combined area under cure endpoints!
QUESTION: Do THY pts do better than pred alone?
Difficult/slow enrollment but enrollment complete (> 100 patients)
Most subjects outside USA
Wolfe G, et al. NEJM in press

42. QMG Score (Mean±SE) by Treatment Group
QMG difference: 2.85 pts (99.5% CI ; p<0.001)

43. Time-Weighted Average AD Prednisone Dose (Mean±SE) by Treatment Group
Prednisone dose difference: 44 mg vs 60 mg (95% CI 7-25 mg; p<0.001)

44. Primary and Subgroup Analyses
Treatment Group
Mean±SD
Estimated
Difference
(95% CI†)
P Valuea
Prednisone
alone
Thymectomy+
prednisone
Primary Analyses
Time-weighted average
Quantitative MG score
8.99 ± 4.93 (N=56)
6.15 ± 4.09 (N=62)
2.85 ( )
< 0.001
alternate-day prednisone dose (mg)
59.8 ± 27.4 (N=56)
43.6 ± 21.2 (N=61)
16.2 ( )
Subgroup Analyses
Time-weighted average Quantitative MG score
Prednisone use at enrollment (interaction with treatment P valueb=0.86)
Not prednisone naїve
9.10 ± 5.06 (N=46)
6.30 ± 3.89 (N=47)
2.80 ( )
0.004
Prednisone naїve
8.84 ± 4.60 (N=9)
5.66 ± 4.79 (N=15)
3.18 ( )
0.12
Gender (interaction with treatment P valueb=0.57)
Female
9.73 ± 5.16 (N=38)
6.47 ± 4.13 (N=46)
3.26 ( )
0.002
Male
7.45 ± 4.11 (N=18)
5.23 ± 3.95 (N=16)
2.22 ( )
Age (years) at disease onset (interaction with treatment P valueb=0.74)
< 40
9.60 ± 5.32 (N=34)
6.50 ± 4.41 (N=42)
3.10 ( )
0.007
≥ 40
7.85 ± 3.50 (N=18)
5.33 ± 2.79 (N=18)
2.52 ( )
0.02
Time-weighted average alternate-day prednisone dose (mg)
Prednisone use at enrollment (interaction with treatment P valueb=0.37)
61.5 ± 28.5 (N=46)
44.3 ± 21.9 (N=46)
17.2 ( )
48.5 ± 19.0 (N=9)
41.5 ± (N=15)
7.0 ( )
0.40
Gender (interaction with treatment P valueb =0.32)
59.19 ± (N=37)
45.76 ± (N=45)
13.43 ( )
0.01
61.08 ± (N=19)
37.70 ± (N=16)
23.38 ( )
0.009
Age (years) at disease onset (interaction with treatment P valueb=0.94)
60.79 ± 27.11(N=33)
44.92 ± (N=41)
15.87 ( )
56.08 ± (N=19)
40.93 ± (N=18)
15.16 ( )
0.07

45. Secondary Analyses Method 1 = maximum dose
Treatment Group
Mean±SD or no./N (%)
Estimated
Difference
(95% CI)
P Value
Prednisone
Alone
Thymectomy
+prednisone
Time-weighted average prescribed AD prednisone dose (mg)a
59.3 ± 28.4
(N=56)
43.4 ± 23.1
(N=62)
16.0 ( )
0.001
Penalized time-weighted average AD prednisone dose (mg; max dose)a,b
72.9 ± 37.4
46.7 ± 24.9
(N=61)
26.3 ( )
< 0.001
Penalized time-weighted AD average prednisone dose (mg; dose at start)a,c
68.1 ± 38.3
45.6 ± 24.3
22.5 ( )
Time-weighted average MG
Activities of Daily Livinga,d
3.41 ± 2.58
(N=55)
2.24 ± 2.09
1.17 ( )
0.008
MG ADL at month 12
3.33 ± 3.40 (N=54)
1.92 ± 2.73 (N=61)
1.42 ( )
0.01
MG ADL at month 24
3.11 ± 2.93 (N=53)
2.02 ± 2.78 (N=59)
1.10 ( )
0.04
MG ADL at month 36
2.69 ± 2.80 (N=51)
2.14 ± 2.92 (N=59)
0.55 ( )
0.32
Azathioprine usee
28/58 (48)
11/65 (17)
31.4% (15.6%,47.1%)
Plasma exchange usee
9/58 (16)
10/65 (15)
0.1% (-12.7%,12.9%) ~1
Intravenous immunoglobulin usee
23/58 (40)
22.7% (7%,38.3%)
0.005
Minimal Manifestation Statuse
at month 12f
20/54 (37)
41/61 (67)
30.2% (12.7%-47.6%)
at month 24f
20/53 (38)
39/59 (66)
28.4% (10.6%-46.2%)
0.003
at month 36f
24/51 (47)
39/58 (67)
20.2% (1.9%-38.5%)
0.03
Hospitalization for MG exacerbation
Months 0-24: # of patientsg
17/60 (28)
6/66 (9)
19.2% (5.9%, 32.6%)
0.006
Cumulative daysh
26.4 ± 28.9
5.5 ± 2.9
0.004
Months 0-36: # of patientsg
22/60 (37)
27.6% (13.6%, 41.6%)
<0.001
22.5± 27.1
8.7 ± 7.7
0.21
Method 1 = maximum dose
Method 2 = Last dose prior to initiation of Prednison

46. Thymectomy Summary Thymectomy study seems to support benefit
But no guarantee of improvement & not Lazarus effect
Multiple procedures
Thymoma is an Absolute Indication
Not Recommended for:
Ocular
Very young children
Mature > 60 yrs old, or ? > 70, or ? > 80
Depends on how old the Rx neurologist is

47. Thymectomy Procedures
Type
Year
Sternal splitting
Early 1900s
Maximally invasive
1980s
Transcervical
1988
Video-assisted thoracoscopic surgery
Late 1990s
Robotics (DaVinci)
Early 2000s

48. Emerging Therapies for MG
Eculizumab – complement inhibitor (Alexion)
Rituximab – monoclonal Ab to B-cells
Belimumab (GSK) – monoclonal to BLS
Subcutaneous immune globulin (Dimachkie)
Grifols – 2 studies using IVIg
Tirasemtiv (Cytokinetics) – inc muscle contraction
Methotrexate
EN101 Antisense oligodeoxynucleotide (Monarsen)
Reduces mRNA that encodes AchE
Phase 1 study completed
Ester Neurosciences/Sussman 2003

49. 86% on ecluz met QMG DOI (3 pt imp) (57% placebo)
Muscle Nerve 2013;48:76-84
14 MG pts – 4 mo RTC crossover
Results:
86% on ecluz met QMG DOI (3 pt imp) (57% placebo)
QMG score sig less after ecluz (p < )
MGADL: eculizumab 9/13 imp 2 pts placebo 3/13
Plan – phase 3 just completed

51. Eculizumab Phase 3 Trial MG Study REGAIN
62 eculizumab pts/63 placebo
Rx: weekly IV x 4 weeks then every 2 weeks x 26 weeks
Primary outcome measure – MGADL change from baseline
Secondary outcome measures – QMG, MG Composite, MG QOL

52. Eculizumab Phase 3 Trial Results

53. Rituximab For AChR-Ab Positive Myasthenia Gravis
PI – R. Nowack
CoPIs – J. Goldstein, M. Dimachkie, R. Barohn
Funded by NeuroNext/NIH
50 pts; 1:1 randomization
Enrolling since mid 2014 – now fully enrolled
Last patient finishes April 2017
Rituximab dose for trial: 375 mg/m2 IV weekly x 4 Repeat in 6 months

54. Open Label Study of Subcutaneous Immunoglobulin (SCIg) in Myasthenia Gravis
M Dimachkie PI
Funded by CSL Bering
Phase 2 multi-center study
25 participants in the IVIg screening phase (ISP)
Primary outcome: % subjects ETP experiencing ≤ 3 points increase in QMG from Week 0 to Week 12
Secondary Outcomes:
MG-ADL, MG-QOL-15, MGC & Treatment Satisfaction Questionnaire (TSQM)
Screening visit
[Week -10]
IVIg Screening phase
[Week -9, -5, -1]
Baseline Visit
[Week 0]
Experimental Treatment Phase
[Week 0.1 – 12]
End of Study visit & follow-up calls
[Week 13, 14, 16]

55. Phase II Trial of Methotrexate in MG Barohn and Muscle Study Group FDA OPD R01 FD003538/IND #101,306
A randomized, double-blind, placebo-controlled study
50 patients
25 receiving MTX; 20mg/week
25 receiving placebo/12 mo study
Hypothesis – adding MTX therapy will improve the MG manifestations so that prednisone dose can be reduced and clinical measures of MG severity will improve
The primary measure of efficacy will be the 9-month prednisone area under the curve (AUC)
Secondary: QMG, MG ADL, MG Comp, MG QOL15
20 sites – KUMC, UTSW, UTSCSA, UC-Irvine, OSU, U. North Carolina, U. Virginia, UCSF – Fresno, U. Miami, U. Indiana, MGH, CPMC, U. Iowa, Toronto, Phoenix, Methodist, NM Center Houston, Penn State, U. Florida, U. Toronto
Conclusion: NEGATIVE STUDY
Pasnoor M, He J, Herbelin L, Burns TM, Nations S, Bril V, Wang AK, Elsheikh BH, Kissel JT, Saperstein D, Shaibani JA, Jackson C, Swenson A, Howard JF, Goyal N, David W, Wichkund M, Pulley M, Becker M, Mozaffar T, Benatar M, Pazcuzzi R, Simpson E, Rosenfeld J, Dimachkie MM, Statland JM, Barohn RJ, The Methotrexate in MG Investigators of the Muscle Study Group. A Randomized controlled trial of methotrexate for patients with generalized myasthenia gravis. Neurology. 2016; 87: PMCID:PMC

56. .

57. MG MTX trial: Baseline Data
Started with 6 sites, expanded to 20 sites due to slow enrollment
Screened: 58, Enrolled: 50 over 2 years
Methotrexate
Placebo
P value
Age of patients
65 ± 10
66 ± 15.8
Gender M/F
19/6
16/9
MGFA Class
Class 2 23 20
Class 3 2 5
Mean Prednisone dose at baseline
22.2
24.6
> 0.05
Mean QMG at baseline
10.5 ± 4.1
10.4 ± 4.2
0.83
MG composite
10 ± 4.7
8.2 ± 4.1
0.39
MMT
9.9 ± 6.62
8.9 ± 6.1
0.24
ADL
4.8 ± 2.71
4.3 ± 2.98
0.41
QOL
± 10.2
21.8 ± 16.7
<0.05

58. Methotrexate vs placebo
MG MTX trial: Results
No significant difference in adverse events
Withdrew at various stages: 8
Methotrexate vs placebo
Visit number (month)
1 Parkinson disease
Placebo
5 (mo 2)
1 Travel problem
Methotrexate
1 Death due to stroke
9 (mo 6)
1 ALT
11 (mo 8)
1 Myalgia
1Worsening MG
1 Worsening MG
14 (mo 11)

59. MG MTX trial: Primary outcome Prednisone area under the curve
Intent-to-treat analysis using multiple imputation method
Mean Prednisone dose in :
Methotrexate group: ±
Placebo : ±
P-value : 0.14
Average daily prednisone dose
Methotrexate group: ± 9.54
Placebo group: ± 7.82

60. MG MTX Trial: Secondary Outcome Measures
Methotrexate Mean change
Placebo mean change
Difference between Placebo and MTX
P value
QMG
-1.6 ±3.5
.28 ± 4.5
1.88
0.08
MGMMT
-5.6 ± 4.6
-3.7 ± 7.7
1.9
0.14
MGQOL
-4.3 ±9.2
-4.8 ± 11.4
0.5
0.38
MGADL
-1.4± 2.3
-0.26± 2.9
1.14
0.059
MG Composite
-4.8 ±4.4
-2.5± 5.4
2.3
0.052
*Intent-to-treat analysis using multiple imputation

61. Post Hoc Analysis
Using the last observation carried forward for missing data
Methotrexate vs placebo
Prednisone: p 0.332
P value
QMG
0.01
MGMMT
0.15
MGQOL
0.18
MGADL
0.02
MG Composite

62. Polyglutamation Assay – with Children’s Mercy Hospital Mara Becker, MD (PI) and Steve Leeder, PharmD, PhD
MTX bioactivated to the polyglutamated form of methotrexate (MTXglun) by folylpolyglutamyl synthase (FPGS)
Polyglutamation determines the biologic activity of methotrexate
Amount of polyglutamation is variable from patient to patient
Rheumatoid arthritis lit suggests patients with highly polyglutamated methotrexate respond better
Additional blood draw at month 12
Personalized medicine approach

63. MG, Methotrexate & Polyglutamation Methods
Analysis of blood drawn from patients enrolled in the 12 month randomized, placebo controlled study of MTX in MG
Red blood cell MTXPGs were measured via ultra performance liquid chromatography and tandem mass spectrometry.
Correlated MTXPGs to MG outcome measures using Spearman Correlation Coefficient

64. Phase II Trial of Methotrexate in MG Results
Polyglutamation analysis performed: 33/50 patients
If on placebo – Below Level Quantified (BLQ)
Of the 25 patients on methotrexate, analyzed 21
Excluded 4
2: no blood draw
1: last visit several months after study ended
1: technical problem
Median age : 64 ± 11.3
Male : female ratio : 16:5

65. Prednisone dose area under the curve (mg) (SD)
Phase II Trial of Methotrexate in MG Results from 21 patients on MTX who had Polyglutamation Testing
MG Outcome
Mean
Baseline
End of study
Difference
Mean QMG (SD)
10.7 (4.2)
9.2 (4.4)
1.6 (3.0)
MG Composite (SD)
10.7 (4.3)
5.2 (5.1)
5.7 (4.8)
MG ADL (SD)
4.9 (2.7)
3.6 (3.2)
1.3 (2.6)
Mean Prednisone dose (mg) (SD)
21.9 (11.9)
8.79 (11.2)
13.1 (9.3)
Prednisone dose area under the curve (mg) (SD)
(2574.7)

66. Correlation with MG outcomes (rho)
Phase II Trial of Methotrexate in MG Results Patients on MTX who had Polyglutamation Testing
Polyglutamates
Correlation with MG outcomes (rho)
MGADL
QMG
MGC
Prednisone dose
Monglutamates
0.20
0.08
0.17
Diglutamates
0.60
0.02
0.39
0.14
Triglutamate
0.38
0.19
0.76
0.36
Tetraglutamate
0.71
0.54
0.30
Pentaglutamate
0.99
0.53
0.15
-0.18
Both coefficients always lie between -1 and +1. The more the correlation coefficient comes closer to -1 or 1, the more there is a correlation between two variables.
r interpretation of strength of correlation
< 0,15 very weak
0,15 - 0,25 weak
0,25 - 0,40 moderate
0,40 - 0,75 strong
>0,75 very strong

67. Phase II Trial of Methotrexate in MG Conclusions Regarding Polglutamation Biomarker
Variable correlations between MTXPG1-5 & MG outcomes (rho range: 0.08 to 0.99)
Strong correlations were seen between:
MTXPG2,4,5 and MGADL
MTXPG4,5 with QMG
MTXPG3 with MGC
Long chain polyglutamates correlate better with MG outcomes
Weak correlations were seen with prednisone dose under the curve
Polyglutamates may be useful biomarker to assess clinical outcomes in MG

68. My Rx Recommendations - prior to 2007 My Rx Recommendations – 2016
Myasthenia Gravis
My Rx Recommendations - prior to 2007
1st Line: Tensilon
Mestinon
Prednisone
Thymectomy
2nd Line: Azathioprine
Mycophenolate Mofetil
Cyclosporine
3rd Line: IVIg
Plasmapheresis
My Rx Recommendations – 2016
1st Line: Enlon
Pyridostigmine
Prednisone
Thymectomy !
2nd Line: Azathioprine
Cyclosporine
IVIg
3rd Line: Plasmapheresis
Mycophenolate Mofetil
Methotrexate
4th Line: Rituximab
? 5th Line: ? Cyclophosphamide
? Tacrolimus

69. MG Rx AND CLINICAL RESEARCH: How Far Have We Come?
Summary
Most MG pts improve
Numerous emerging and encouraging therapies
MGFA guidelines for trials
Improved & standardized classification & measures
Without a home-run Rx, controlled trials are necessary (even for established Rx!) but there may be exceptions
Need adequately powered & well designed studies
MG trials are very hard, especially recruitment (? Why)
Even in a controlled trial, placebo pts can improve
and most pts respond to prednisone
therefor difficult to do
Some things in clinical research we have no control over!
Fertile territory for clinical investigation