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<h5 class="section-title" id="d7290510e383">Question</h5>
<p id="d7290510e385">What are the frequency and characteristics of neurological complications
from
anti–programmed death 1 (PD-1) antibody use?
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<h5 class="section-title" id="d7290510e388">Findings</h5>
<p id="d7290510e390">Among 347 patients treated with anti–programmed death 1 (PD-1)
antibody use
(pembrolizumab or nivolumab), this cohort study supports a low frequency (2.9%) of
neurological complications associated with anti–PD-1 therapy. The range and
severity of complications are diverse, including necrotizing myopathy, various
neuropathies, cerebellar ataxia, internuclear ophthalmoplegia, retinopathy, and
headache; the median modified Rankin Scale score of 2.5 indicates mild to moderate
disability.
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<h5 class="section-title" id="d7290510e393">Meaning</h5>
<p id="d7290510e395">Subacute presentation of neurological symptoms in a patient receiving
anti–PD-1
therapy should prompt consideration of an association and discontinuation of
anti–PD-1 antibody use and possible treatment with corticosteroids or other immune
treatment depending on the severity.
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<h5 class="section-title" id="d7290510e399">Importance</h5>
<p id="d7290510e401">Neurological complications are an increasingly recognized consequence
of the use of
anti–programmed death 1 (PD-1) antibodies in the treatment of solid-organ tumors,
with an estimated frequency of 4.2%. To date, the clinical spectrum and optimum
treatment approach are not established.
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<h5 class="section-title" id="d7290510e404">Objective</h5>
<p id="d7290510e406">To investigate the frequency, clinical spectrum, and optimum
treatment approach to
neurological complications associated with anti–PD-1 therapy.
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<h5 class="section-title" id="d7290510e409">Design, Setting, and Participants</h5>
<p id="d7290510e411">This single-center, retrospective cohort study was conducted
from either September
or
December 2014 (the approval dates of the study drugs by the US Food and Drug
Administration) to May 19, 2016. All patients receiving anti–PD-1 monoclonal
antibodies were identified using the Mayo Cancer Pharmacy Database. Patients with
development of neurological symptoms within 12 months of anti–PD-1 therapy were
included. Patients with neurological complications directly attributable to metastatic
disease or other concurrent cancer-related treatments were excluded.
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<h5 class="section-title" id="d7290510e414">Main Outcomes and Measures</h5>
<p id="d7290510e416">Clinical and pathological characteristics, time to development
of neurological
symptoms, and modified Rankin Scale (mRS) score.
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<h5 class="section-title" id="d7290510e419">Results</h5>
<p id="d7290510e421">Among 347 patients treated with anti–PD1 monoclonal antibodies
(pembrolizumab or
nivolumab), 10 (2.9%) developed subacute onset of neurological complications. Seven
patients were receiving pembrolizumab, and 3 patients were receiving nivolumab. The
patients included 8 men and 2 women. Their median age was 71 years (age range, 31-78
years). Neurological complications occurred after a median of 5.5 (range, 1-20) cycles
of anti–PD-1 inhibitors. Complications included myopathy (n = 2),
varied neuropathies (n = 4), cerebellar ataxia (n = 1),
autoimmune retinopathy (n = 1), bilateral internuclear ophthalmoplegia
(n = 1), and headache (n = 1). Peripheral neuropathies included
axonal and demyelinating polyradiculoneuropathies (n = 2), length-dependent
neuropathies (n = 1), and asymmetric vasculitic neuropathy
(n = 1). The time to maximum symptom severity varied from 1 day to more than
3 months. The median mRS score was 2.5 (range, 1-5), indicating mild to moderate
disability. Five patients experienced other systemic immune-mediated complications,
including hypothyroidism (n = 3), colitis (n = 2), and hepatitis
(n = 1). Treatment with anti–PD-1 antibodies was discontinued in 7
patients. Treatment included corticosteroids (n = 7), intravenous
immunoglobulin (n = 3), and plasma exchange (n = 1). Nine
patients improved, with a median mRS score of 2 (range, 0-6). One patient with severe
necrotizing myopathy died.
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<h5 class="section-title" id="d7290510e424">Conclusions and Relevance</h5>
<p id="d7290510e426">Neurological adverse events associated with anti–PD-1 therapy
have a diverse
phenotype, with more frequent neuromuscular complications. Although rare, they will
likely be encountered with increasing frequency as anti–PD-1 therapy expands to
other cancers. The time of onset is unpredictable, and evolution may be rapid and
life-threatening. Prompt recognition and discontinuation of anti–PD-1 therapy is
recommended. In some cases, immune rescue treatment may be required.
</p>
</div><p class="first" id="d7290510e429">This cohort study investigates the frequency,
clinical spectrum, and optimum treatment
approach to neurological complications associated with anti–PD-1 inhibitor use.
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