PD-L1 expression and CD8+ infiltration shows heterogeneity in juvenile recurrent respiratory papillomatosis

Pharmacotherapy for recurrent respiratory papillomatosis (RRP): a treatment update

Introduction: Recurrent respiratory papillomatosis is a rare human papillomavirus (HPV)-induced condition where warts grow within the airway and especially the larynx to effect voice and restrict breathing.Areas covered: A PubMed search using the following search terms was performed: respiratory papillomatosis and cidofovir, alpha-interferon, bevacizumab, PD1, and HPV vaccines. Surgery remains the mainstay of treatment. There has been a change in options available for adjuvant therapies with systemic bevacizumab and the potential benefits of prophylactic HPV vaccine. Despite efforts to identify a drug therapy to control RRP, no therapy yet remains which is predictable and effective in all. The current status of therapeutic vaccines and immunotherapy is discussed.Expert opinion: The current adjuvant therapies do offer a reasonable expectation of control but the effect for the individual is unpredictable despite the therapies being based on good science. The current therapies would allow an escalating treatment strategy to be formulated, however a single therapy is unlikely to be curative. Multi-center trials are required such that adequate numbers to show an effect are achieved.

Biologics for the Treatment of Recurrent Respiratory Papillomatosis

This article aims to educate readers on adjuvant therapies for recurrent respiratory papillomatosis (RRP). Although antivirals are injected locally into papillomas as an adjuvant treatment, new biologics targeting vascular endothelial growth factor or induction of human papillomavirus (HPV)-specific immunity are gaining traction with demonstration of clinical benefit and mechanism of action in retrospective case series and prospective clinical trials. The future of RRP treatment, alone or in combination with surgery, lies in the careful clinical study of vascular and immune targeting agents that balance the risk of adverse events with the chance for elimination of HPV-infected cells.

How Enhancing Immunity to Low-Risk HPV Could Cure Recurrent Respiratory Papillomatosis

Recurrent respiratory papillomatosis (RRP) is currently treated with repeat surgical resection of papillomatous disease that does not address the fundamental underlying issue of chronic infection with low-risk human papillomavirus. Here, we review the biology and immunology of low-risk human papillomavirus (HPV) infections. Antiviral or antiangiogenic adjuvant treatments similarly address the papillomatous disease itself but do not activate HPV immunity. It is likely that only through immune-mediated clearance of low-risk HPV infection can patients with RRP be cured. In some patients, this occurs spontaneously. In others with more aggressive disease, adjuvant immunotherapy to activate immunity may be needed. Based on current understanding of antiviral immune responses, the only rational strategy to clear HPV-infected epithelial cells is through activation of the T-lymphocyte arm of the adaptive immune response. Translation of immunotherapies that are Food and Drug Administration-approved or under clinical study for cancer, such as immune checkpoint blockade or engineered therapeutic vaccines, may provide a path toward tolerable and efficacious adjuvant immunotherapy for RRP. LEVEL OF EVIDENCE: NA Laryngoscope, 131:2041-2047, 2021.

Fit-For-Purpose PD-L1 Biomarker Testing For Patient Selection in Immuno-Oncology: Guidelines For Clinical Laboratories From the Canadian Association of Pathologists-Association Canadienne Des Pathologistes (CAP-ACP)

Since 2014, programmed cell death protein 1 (PD-1)/programmed cell death ligand 1 (PD-L1) checkpoint inhibitors have been approved by various regulatory agencies for the treatment of multiple cancers including melanoma, lung cancer, urothelial carcinoma, renal cell carcinoma, head and neck cancer, classical Hodgkin lymphoma, colorectal cancer, gastroesophageal cancer, hepatocellular cancer, and other solid tumors. Of these approved drug/disease combinations, a subset also has regulatory agency-approved, commercially available companion/complementary diagnostic assays that were clinically validated using data from their corresponding clinical trials. The objective of this document is to provide evidence-based guidance to assist clinical laboratories in establishing fit-for-purpose PD-L1 biomarker assays that can accurately identify patients with specific tumor types who may respond to specific approved immuno-oncology therapies targeting the PD-1/PD-L1 checkpoint. These recommendations are issued as 38 Guideline Statements that address (i) assay development for surgical pathology and cytopathology specimens, (ii) reporting elements, and (iii) quality assurance (including validation/verification, internal quality assurance, and external quality assurance). The intent of this work is to provide recommendations that are relevant to any tumor type, are universally applicable and can be implemented by any clinical immunohistochemistry laboratory performing predictive PD-L1 immunohistochemistry testing.

Clinical Activity of Nivolumab for Human Papilloma Virus-Related Juvenile-Onset Recurrent Respiratory Papillomatosis

BACKGROUND

Juvenile-onset recurrent respiratory papillomatosis (JO-RRP) is a human papilloma virus-mediated progressive benign neoplasm that affects children and young adults. Primary management consists of regular surgical debulking to maintain airway patency and vocal function. Like condyloma acuminata, JO-RRP is associated with immune dysregulation, and T cells isolated from papillomas express an anergic phenotype. Therefore, we hypothesized that programmed death protein 1 axis inhibition could stabilize tumor growth.

MATERIALS AND METHODS

We treated two patients with refractory JO-RRP using nivolumab, with the primary objective of assessing clinical activity. We explored baseline papilloma features using immunohistochemistry and comprehensive genomic profiling.

RESULTS

Both patients experienced symptomatic improvement, and interval laryngoscopies revealed a reduction in papillomatosis burden. One patient has not required subsequent surgical debridement for almost 2 years. On pathologic examination of pretreatment papillomas from both cases, infiltrating T cells were evident in the papilloma stroma, and papilloma programmed death ligand 1 expression was absent. Papilloma mutational load ranged between three and six mutations per megabase for each case. From on-treatment biopsy tissue, a higher amount of intraepithelial T cells and programmed death ligand 1 expression were detected in the papilloma.

CONCLUSION

Nivolumab appears to have promising activity in JO-RRP, and further clinical investigation with more patients in clinical trials is warranted.

IMPLICATIONS FOR PRACTICE

To the authors' knowledge, this article is the first report describing clinical activity with a programed cell death-1 (PD-1) inhibitor to treat a rare but detrimental type of respiratory tract epithelial neoplasm that afflicts young adults. Two patients were treated, and tumor features, such as mutational load, were examined with the intent to stimulate future hypotheses for translational research. The safety and activity of PD-1 inhibitors in this population still need to be corroborated in clinical trials and should not yet be adopted into clinical practice.

Squamous Cell Papillomatosis in the Setting of Recurrent Respiratory Papillomatosis

A 23 year old male presented to the Otolaryngology clinic with 6 months of hoarseness and poor voice projection without improvement from speech therapy or medical anti-reflux medication. Upon examination he was found to have multiple polypoid lesions emanating from bilateral false vocal folds, left true vocal fold, and the anterior commissure. Biopsy and potassium titanyl phosphate (KTP) laser ablation with bevacizumab injection provided treatment and confirmed the clinical suspicion of squamous cell papilloma. Despite 3 years of treatment, the papillomatosis proved difficult to control, requiring a procedure approximately every 3 months. In an attempt to control the course of the disease the patient received a series of three bevacizumab and three cidofovir injections. Serial biopsies showed mild atypia within the squamous cell papillomas. Two separate biopsies confirmed presence of human papillomavirus (HPV) 6/11 via in situ hybridization with appropriate controls. There is promising research that the quadrivalent HPV (types 6, 11, 16, and 18) vaccine both reduces the disease burden in patients with active disease and reduces the incidence of recurrent respiratory papillomatosis (RRP). Other studies have shown that local immunologic dysregulation may play a role in RRP pathogenesis. Therefore new treatment options, to include PDL-1 blockade, offer hope in treating this benign condition with high morbidity and rare mortality.