Results
During the study period, the total prescriptions of tocilizumab was 362,
which included 170 (46.96%) on-label prescriptions and 192 (53.04%)
off-label prescriptions. The prescriptions were mainly from rheumatology
and immunology department, which occupied 98.9% of total prescriptions.
The median patients age is 36, ranging from 14 to 87. The number of
prescription physicians were 31 (chief physician 13; vice chief
physician 9; attending physician 9. vice chief physician was the
majority of the health care group whose ratio of prescribing off-label
use prescription is 56.52% and followed by attending physician
(52.97%) and chief physician (50.55%) . According to the analysis of
logistic regression, the off-label use of tocilizumab was similar among
physicians with different professional title(R=0.039, P=0.755).
The patient number of each off label indication was also analyzed. The
total patient number is 167. According to our standard, 16 out of 18
kinds of indications were judged as off-label indications. Takayasu
Arteritis(27, 16.2%) was the most frequently prescribed off-label
indication. Other off-label indications were Adult-onset Still’s
disease(13, 7.8%), Systemic Lupus Erythematosus(2, 1.2%), Systemic
Vasculitis(13, 7.8%), Giant Cell Arteritis(5, 3.0%), Relapsing
Polychondritis(4, 2.4%), Behcet’s Disease(8, 4.8%), Sjogren’s
Syndrome(4, 2.4%), Dermatomyositis(5, 3.0%), Systemic Scleroderma,(4,
2.4%) Neuromyelitis Optic Spectrum Disease(1, 0.6%), Castleman
Disease(1, 0.6%), Polymyalgia Rheumatica(1, 0.6%),
Immune-mediated necrotizing
myopathy(1, 0.6%), Ankylosing Spondylitis(1, 0.6%) and Psoriatic
Arthritis(1, 0.6%). The on-label indication is Rheumatoid arthritis
(74, 44.3%) and systemic juvenile idiopathic arthritis (2, 1.2%).
Additionally, most of the patients(163, 97.6%) prescribed tocilizumab
from the rheumatology and immunology department. Other patients were
from Pneumology Department (2, 1.2%), Department of Cardiology (1,
0.6%) and Vascular Surgery Department (1,0.6%). The details are
available at table 1.
According to our criterion of judging the evidence categories supporting
these off label indications.
Castleman’s disease and giant cell
arteritis has been approved by other countries like the US, the European
regulatory authorities and Japan so these two indications are classified
as category I. Takayasu Arteritis, adult-onset Still’s disease,
relapsing polychondritis, Behcet’s disease, systemic scleroderma,
neuromyelitis optic spectrum disease and polymyalgia rheumatica are
classified as category II. Besides all the category II indications have
systematic review, RCT or cohort study support. Ankylosing Spondylitis,
Sjögren’s Syndrome, Systemic Lupus Erythematosus are supported by
systemic review, RCT, cohort study, non-randomized controlled study, so
these indications are classified as category III. Dermatomyositis,
Psoriatic Arthritis, Systemic Vasculitis are supported by case series
report or case report, so these indications are classified as category
IV. Finally, immune-mediated necrotizing myopathy have no medical
evidences support so this indication is classified as category V. The
details are available at table 2 and table 3.