Clinical utility of plasma cell-free DNA in pancreatic neuroendocrine neoplasms.

In advanced pancreatic neuroendocrine neoplasms (PanNEN), there are little data detailing the frequency of genetic alterations identified in cell free DNA (cfDNA), plasma-tissue concordance of detected alterations, and clinical utility of cfDNA. Patients with metastatic PanNENs underwent cfDNA collection in routine practice. Next-generation sequencing (NGS) of cfDNA and matched tissue when available was performed. Clinical actionability of variants was annotated by OncoKB. Thirty-two cfDNA samples were analyzed from 25 patients, the majority who had well-differentiated intermediate grade disease (13/25; 52%). Genomic alterations were detected in 68% of patients and in 66% of all cfDNA samples. The most frequently altered genes were DAXX (28%), TSC2 (24%), MEN1 (24%), ARID1B (20%), ARID1A (12%), and ATRX (12%). Twenty-three out of 25 (92%) patients underwent tumor tissue NGS. Tissue-plasma concordance for select genes was as follows:DAXX (95.7%), ARID1A (91.1%), ATRX (87%), TSC2 (82.6%), MEN1 (69.6%). Potentially actionable alterations were identified in cfDNA of 8 patients, including TSC2 (4; level 3b), ATM (1; level 3b), ARID1A (2; level 4), and KRAS (1; level 4). An ETV6:NTRK fusion detected in tumor tissue was treated with larotrectinib; at progression, sequencing of cfDNA identified an NTRK3 G623R alteration as the acquired mechanism of resistance; the patient enrolled in a clinical trial of a second-generation TRK inhibitor with clinical benefit. In metastatic PanNENs, cfDNA-based NGS identified tumor-associated mutations in 66% of plasma samples with a high level of plasma-tissue agreement in PanNEN-associated genes. Clonal evolution, actionable alterations, and resistance mechanisms were detected through circulating cfDNA genotyping.

Pembrolizumab alone and pembrolizumab plus chemotherapy in previously treated, extrapulmonary poorly differentiated neuroendocrine carcinomas.

BACKGROUND: To date, single-agent immune checkpoint inhibitor (CPI) therapy has proven to be ineffective against biomarker-unselected extrapulmonary poorly differentiated neuroendocrine carcinomas (EP-PDNECs). The efficacy of CPI in combination with chemotherapy remains under investigation. METHODS: Patients with advanced, progressive EP-PDNECs were enrolled in a two-part study of pembrolizumab-based therapy. In Part A, patients received pembrolizumab alone. In Part B, patients received pembrolizumab plus chemotherapy. PRIMARY ENDPOINT: objective response rate (ORR). Secondary endpoints: safety, progression-free survival (PFS) and overall survival (OS). Tumours were profiled for programmed death-ligand 1 expression, microsatellite-high/mismatch repair deficient status, mutational burden (TMB), genomic correlates. Tumour growth rate was evaluated. RESULTS: Part A (N = 14): ORR (pembrolizumab alone) 7% (95% CI, 0.2-33.9%), median PFS 1.8 months (95% CI, 1.7-21.4), median OS 7.8 months (95% CI, 3.1-not reached); 14% of patients (N = 2) had grade 3/4 treatment-related adverse events (TRAEs). Part B (N = 22): ORR (pembrolizumab plus chemotherapy) 5% (95% CI, 0-22.8%), median PFS 2.0 months (95% CI, 1.9-3.4), median OS 4.8 months (95% CI, 4.1-8.2); 45% of patients (N = 10) had grade 3/4 TRAEs. The two patients with objective response had high-TMB tumours. DISCUSSION: Treatment with pembrolizumab alone and pembrolizumab plus chemotherapy was ineffective in advanced, progressive EP-PDNECs. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov NCT03136055.

A Randomized Trial Evaluating Patient Experience and Preference Between Octreotide Long-Acting Release and Lanreotide for Treatment of Well-Differentiated Neuroendocrine Tumors.

PURPOSE: Somatostatin analogs octreotide long-acting release (octLAR) and lanreotide are equally acceptable in National Comprehensive Cancer Network guidelines for neuroendocrine tumors (NETs). Lanreotide is more expensive and given by deep subcutaneous injection, whereas octLAR is given intramuscularly. We evaluated patient preference between these agents in terms of injection site pain. MATERIALS AND METHODS: Randomized, single-blinded study. Patients with NETs received injections every 4 weeks. Arm 1: octLAR × 3, then lanreotide × 3; arm 2: reverse order. Self-reported injection site pain scores (range, 0-10) were obtained after each of the first three injections. Primary end point was comparison of mean pain scores over the first three injections. Secondary end points included patient-reported preference. RESULTS: Fifty-one patients enrolled (26 in arm 1 and 25 arm 2), all evaluable for primary end point. No significant difference was identified in the mean pain score over the first three injections (2.4 ± 1.9 v 1.9 ± 1.5, P = .5). Thirty-four of 51 (67%) patients (15 in arm 1 and 19 in arm 2) completed post-therapy questionnaires and were evaluable for secondary end points. Seven patients (47%) in arm 1 and eight patients (42%) in arm 2 indicated no drug preference at the end of treatment. In the other 19 patients, more patients indicated mild or strong preference for octLAR over lanreotide. CONCLUSION: We found minimal pain with octLAR and lanreotide and no significant pain score differences between the two. Patients indicating a drug preference trended toward favoring octLAR.