Worsening of anti-Hu paraneoplastic neurological syndrome related to anti-PD-1 treatment: Case report and review of literature

We present an illustrative case of a 62-year-old woman with small cell lung cancer who developed progressive worsening of pre-existing anti-Hu antibody associated sensory neuronopathy after treatment with programmed cell death-1 (PD-1) inhibitor, nivolumab. We review the literature and identify 6 reported cases to understand the clinical outcomes of patients with anti-Hu paraneoplastic neurologic syndrome (PNS) treated with anti-PD-1 treatment. The PNS clinical spectrum comprised of encephalitis, a combination of sensory neuronopathy and anti-NMDAR encephalitis, isolated sensory neuronopathy, and encephalomyelitis. Immune checkpoint inhibitor have the potential to worsen pre-existing anti-Hu PNS and may promote the development of anti-Hu PNS. [Display omitted] •Immune checkpoint inhibitors (ICI) have the potential to worsen pre-existing anti-Hu paraneoplastic neurologic syndrome (PNS).•Two of the three patients with known anti-Hu antibody prior to introduction of anti-PD-1 inhibitor died and the other one had severe disability.•The decision to start ICI in patients with pre-existing PNS should be carefully evaluated after having a risks and benefits discussion.