Herpes Zoster Following Pembrolizumab in Metastatic NSCLC: A Case Report

Medical literature has documented cases of herpes zoster and other severe mucocutaneous reactions in patients with metastatic non-small cell lung cancer receiving immunotherapy, specifically with the PD-1 inhibitor pembrolizumab.

A case report published in Cureus details an instance of herpes zoster occurring following chemo-immunotherapy with pembrolizumab in a patient with metastatic non-small cell lung cancer.

Understanding PD-1 Inhibitors and Immune Response

Pembrolizumab is a targeted cancer therapy approved for the treatment of various metastatic malignancies, including lung cancer. As a PD-1 inhibitor, it works by blocking the programmed cell death protein 1 (PD-1) receptor, which helps the immune system recognize and attack cancer cells.

While these therapies can be effective in treating advanced cancers, they can also trigger immune-related adverse events. These toxicities can manifest in various organ systems, including the skin.

Herpes Zoster and Immunotherapy

Herpes zoster, commonly known as shingles, is a reactivation of the varicella-zoster virus. Research indicates that patients treated with PD-1/PD-L1 inhibitors may be susceptible to this condition.

A study published in Translational Cancer Research in March 2022 specifically examined herpes zoster in lung cancer patients treated with PD-1/PD-L1 inhibitors. The authors noted that because the study was a retrospective small study, further prospective observational studies are required to better understand the phenomenon.

Severe Skin Toxicities and SJS-Like Reactions

Beyond viral reactivations, pembrolizumab has been linked to more severe and rare blistering disorders. One documented case involved an 80-year-old woman with metastatic non-small cell lung cancer who experienced a Stevens-Johnson Syndrome (SJS)-like reaction.

According to a report in the Journal of Investigative Medicine High Impact Case Reports, this patient developed an eruption involving the oral mucosa. The reaction occurred after 15 weeks of exposure to pembrolizumab, consisting of six doses.

The report further specifies that this SJS-like reaction appeared seven days after the patient received one dose of a recombinant zoster vaccine.

Stevens-Johnson Syndrome is described as a rare blistering disorder characterized by significant morbidity and a high mortality rate.

Clinical Context and Implications

The occurrence of these reactions highlights the complexity of managing patients on immune checkpoint inhibitors. The interaction between the drug, the patient’s underlying malignancy, and other medical interventions—such as vaccinations—can contribute to rare but severe skin toxicities.

Medical professionals monitor these patients closely for immune-related adverse events, as these reactions can be inconsistently reported and vary widely in severity.

• Pembrolizumab is used for metastatic non-small cell lung cancer.
• Herpes zoster has been observed in patients receiving PD-1/PD-L1 inhibitors.
• SJS-like reactions are rare but can occur, potentially involving the oral mucosa.
• The timing of these reactions may correlate with the number of doses received or the administration of other medical treatments, such as vaccines.