Immune checkpoint inhibitor related myasthenia gravis: single center experience and systematic review of the literature

Safa, Houssein; Johnson, Daniel H; Trinh, Van Anh; Rodgers, Theresa E; Lin, Heather; Suarez-Almazor, Maria E; Fa’ak, Faisal; Saberian, Chantal; Yee, Cassian; Davies, Michael A; Tummala, Sudhakar; Woodman, Karin; Abdel-Wahab, Noha; Diab, Adi

doi:10.1186/s40425-019-0774-y

Table 2 Clinical characteristics, diagnostic findings, management, and outcomes of ICI-related MG in patients with pre-existing MG (n = 13) and those with new onset disease (n = 52)^a

From: Immune checkpoint inhibitor related myasthenia gravis: single center experience and systematic review of the literature

Variable	New Onset (n = 52); n (%)	Pre-existing MG (n = 13); n (%)	p value
Median time from ICI initiation to onset of MG symptoms (weeks)			0.27
	4	4.7
MGFA classification			0.161
I	7 (14)	1 (8)
II	14 (27)	0
III	6 (12)	2 (15)
IV	2 (4)	2 (15)
V	23 (44)	6 (46)
Clinical presentation
Ptosis	43 (83)	6 (46)	0.01
Dyspnea	32 (62)	8 (62)	1
Limb weakness	30 (58)	6 (46)	0.54
Dysphagia	24 (46)	7 (54)	0.76
Diplopia	22 (42)	5 (39)	0.8
Neck weakness	20 (39)	2 (15)	0.19
Myalgias	13 (25)	0	0.06
Blurry vision	7 (14)	0	0.33
Dysarthria	6 (12)	2 (15)	0.65
Generalized weakness	6 (12)	0	0.34
Dysphonia	6 (12)	1 (8)	1
Facial weakness	5 (10)	3 (23)	0.19
Nasal speech/weakness of the palatal muscles	5 (10)	1 (8)	1
Incontinence	2 (4)	0	1
Diagnostic tools
Auto antibody panel positive titers
Anti-AChR	32/50 (64)	5/6 (83)	0.65
Anti-Striated muscle	12/18 (67)	0/0	N/A
Muscle enzymes elevation
CPK	37/44 (84)	4/5 (80)	1
Troponin	12/13 (92)	1/1 (100)	1
Edrophonium test positive	5/5 (100)	0	N/A
Ice pack test positive	2/4 (50)	0	N/A
Electrodiagnostic studies (skeletal muscle EMG, RNS, NCS)
MG	14/34^b (41)	2/3 (67)	0.56
Myopathy	6/34^c (18)	0/3	0.58
MG and myopathy	6/34^c (18)	0/3	0.33
Polyneuropathy	2/34 (6)	1/3 (33)	0.23
No pathologic findings	6/34 (18)	0/3	0.58
Treatment of MG
Corticosteroids	48 (92)	11/11^d (100)	1
Acetylcholinesterase inhibitors	25 (48)	7/11^d (64)	0.35
IVIG	25 (48)	5/11^d (46)	0.87
Plasmapheresis	22 (42)	6/11^d (55)	0.52
Other IST (MMF, rituximab, infliximab or tacrolimus)	7 (13)	3/11^d (27)	0.36
IA	3 (6)	0/11^d	1
ICI holding/discontinuation	51 (98)	10/11^d (91)	0.32
MG outcome
Complete resolution	8/51 (16)	4/11^d (36)^e	0.2
Improvement	30/51^e (59)	4/11^d (36)	0.2
Deterioration	13/51^e (26)	3/11^d (27)	1
Death	21 (40)	3 (23)	0.34
MG complications	13 (25)	2 (15)	0.72
Cancer progression	4 (8)	0	0.58
Other comorbidities	2 (4)	1 (8)	0.5
Unspecified	2 (4)	0	1

^aAbbreviations: MG myasthenia gravis, ICI immune checkpoint inhibitor, MGFA Myasthenia Gravis Foundation of America, Anti-AChR Anti-Acetylcholine receptor, CPK creatine phosphokinase, EMG electromyography, RNS repetitive nerve stimulation, NCS nerve conduction study, IVIG intravenous immunoglobulin, IST immunosuppressive therapy, MMF mycophenolic acid, IA immunoadsorption. Numbers are rounded to the nearest whole number
^bThree patients also had findings suggestive of polyneuropathy
^cTwo patients also had findings suggestive of polyneuropathy
^dTwo patients with pre-existing MG did not develop a flare of their disease after ICI initiation and were excluded from the analysis
^eData were not reported for one patient

Back to article page