Tumour response to TRK inhibition in a patient with pancreatic adenocarcinoma harbouring an NTRK gene fusion
ANNALS OF ONCOLOGY
Authors: O'Reilly, E. M.; Hechtman, J. F.
Abstract
Background: Although rare, NTRK gene fusions are known to be oncogenic drivers in pancreatic ductal adenocarcinoma (PDAC). We report the response of a metastatic CTRC-NTRK1 gene fusion-positive PDAC to targeted treatment with the oral tropomyosin receptor kinase (TRK) inhibitor larotrectinib and the eventual development of resistance to treatment. Patient, methods and results: A 61-year-old woman presented with a 2.5-cm mass in the body of the pancreas and a 1.2-cm liver lesion on routine follow-up for endometrial cancer that was in complete remission. Liver biopsy confirmed a primary PDAC unrelated to the endometrial cancer. The patient was treated with gemcitabine, nab-paclitaxel and ADI-PEG 20 for 12 months until disease progression and toxicity emerged [best overall response (BOR): partial response (PR)]. The patient switched to a modified regimen of folinic acid, fluorouracil, irinotecan and oxaliplatin for 4 months until neuropathy occurred. Oxaliplatin was withheld until disease progression 6 months later (BOR: stable disease). Despite recommencing oxaliplatin, the disease continued to progress. At this time, somatic profiling of the liver lesion revealed a CTRC-NTRK1 gene fusion. Treatment with larotrectinib 100 mg twice daily was commenced with BOR of PR at 2 months. The patient progressed after 6 months and was re-biopsied. Treatment was switched to the investigational next-generation TRK inhibitor selitrectinib (BAY 2731954, LOXO-195) 100 mg twice daily. After 2 months, the disease progressed and dabrafenibtrametinib combination therapy was initiated due to existence of a BRAF-V600E mutation. However, the cancer continued to progress and the patient died 2 months later. Conclusions: Targeted TRK inhibition with larotrectinib in PDAC harbouring a CTRC-NTRK1 gene fusion is well tolerated and can improve quality of life for the patient. However, acquired resistance to therapy can emerge in some patients. Next-generation TRK inhibitors such as selitrectinib are currently in development to overcome this resistance.
Known genetic susceptibility factors for chronic pancreatitis in patients of European ancestry are rare in patients of African ancestry
PANCREATOLOGY
Authors: Phillips, Anna Evans; LaRusch, Jessica; Greer, Phil; Abberbock, Judah; Alkaade, Samer; Amann, Stephen T.; Anderson, Michelle A.; Baillie, John; Abanks, Peter; Brand, Randall E.; Conwell, Darwin; Cote, Gregory A.; Forsmark, Christopher E.; Gardner, Timothy B.; Gelrud, Andres; Guda, Nalini; Lewis, Michele; Money, Mary E.; Muniraj, Thiruvengadam; Sandhu, Bimaljit S.; Sherman, Stuart; Singh, Vikesh K.; Slivka, Adam; Tang, Gong; Wilcox, C. Mel; Whitcomb, David C.; Yadav, Dhiraj
Abstract
Background: Multiple pathogenic genetic variants are associated with pancreatitis in patients of European (EA) and Asian ancestries, but studies on patients of African ancestry (AA) are lacking. We evaluated the prevalence of known genetic variations in African-American subjects in the US. Methods: We studied prospectively enrolled controls (n = 238) and patients with chronic (CP) (n = 232) or recurrent acute pancreatitis (RAP) (n = 45) in the NAPS2 studies from 2000-2014 of self-identified AA. Demographic and phenotypic information was obtained from structured questionnaires. Ancestry and admixture were evaluated by principal component analysis (PCA). Genotyping was performed for pathogenic genetic variants in PRSS1, SPINK1, CFTR and CTRC. Prevalence of disease-associated variants in NAPS2 subjects of AA and EA was compared. Results: When compared with CP subjects of EA (n = 862), prevalence of established pathogenic genetic variants was infrequent in AA patients with CP, overall (29 vs. 8.19%, OR 4.60, 95% CI 2.74-7.74, p < 0.001), and after stratification by alcohol etiology (p < 0.001). On PCA, AA cases were more heterogeneous but distinct from EA subjects; no difference was observed between AA subjects with and without CP-associated variants. Of 19 A A patients with CP who had pathogenic genetic variants, 2 had variants in PRSS1 (R122H, R122C), 4 in SPINK1 (all N34S heterozygotes), 12 in CFTR (2 CFTRsev, 9 CFTRBD, 1 compound heterozygote with CFTRsev and CFTRBD), and 1 in CTRC (R254W). Conclusion: Pathogenic genetic variants reported in EA patients are significantly less common in AA patients. Further studies are needed to determine the complex risk factors for AA subjects with pancreatitis. (C) 2018 Published by Elsevier B.V. on behalf of IAP and EPC.