Response rates to cytotoxics in gastro-entero-pancreatic neuroendocrine tumors (GEP-NETs) vary; recent trials demonstrated lack of objective response rates in up to 70% of patients. Identification of predictive therapeutic biomarkers would be beneficial in the treatment of GEP. Selected markers with known or suspected capability of predicting response to cytotoxics or prognosis (Ki-67, p53, multidrug resistance protein-1 (MDR1), Akt, thymidylate synthase (TS), phosphatase and tensin homolog (PTEN), CA9, cluster of differentiation 34 (CD34), vascular endothelial growth factor (VEGF), hypoxia-inducible factor (HIF)-1, mismatch repair gene – human mutL homolog 1 (hLMH1), and Bcl-2) were analyzed using immunohistochemisrtry in 60 treatment-naive patients receiving chemotherapy (n=46) or chemoembolization (n=14) for inoperable advanced and/or metastatic GEP and correlated with prognosis (survival and response rates). Therapy included systemic chemotherapy with streptozotocin (n=28), doxorubicin (n=14), 5-fluorouracil (n=18), and etoposide/cisplatinum (n=16), or chemoembolization (streptozotocin, 9; doxorubicin, 5). Factors associated with overall survival in the entire cohort were Ki-67, P<0.001; tumor grade, P<0.001; tumor differentiation, P<0.001; CA9, P=0.004; Akt, P=0.01; HIF-1, P<0.001; p53, P<0.0001; and hMLH1, P=0.005. Markers associated with treatment response included overall group: Akt and PTEN (P=0.05 and 0.05 respectively); streptozotocin: Akt (P=0.07), TS (P=0.02), and PTEN (P=0.017); doxorubicin: Ki-67 (P=0.05), Akt (P=0.06), and CA9 (P=0.02). At multivariate analysis, Akt was significantly associated with a nonresponse to therapy (objective response (OR): 0.2 (0.05–0.8)). For patients receiving only systemic chemotherapy (n=46), PTEN (0.04) and hLMH1 (0.03) were correlated with treatment response and for individual molecules were streptozotocin: PTEN (P=0.008) and hLMH1 (0.07); doxorubicin: Akt (P=0.09), CA9 (P=0.09), and hLMH1 (P=0.09). These results demonstrate a number of new prognostic biomarkers in GEP-NET, and in addition, response to chemotherapy was correlated with a simple panel of selected markers (such as CA9, Akt, PTEN, TS, and hLMH1).
Dermot O'Toole, Anne Couvelard, Vinciane Rebours, Magali Zappa, Olivia Hentic, Pascal Hammel, Philippe Levy, Pierre Bedossa, Eric Raymond, and Philippe Ruszniewski
Bertrand Brieau, Olivia Hentic, Rachida Lebtahi, Maxime Palazzo, Makrem Ben Reguiga, Vinciane Rebours, Frederique Maire, Pascal Hammel, Philippe Ruszniewski, and Pierre Fenaux
Jonathan R Strosberg, James C Yao, Emilio Bajetta, Mounir Aout, Bert Bakker, John D Hainsworth, Philippe B Ruszniewski, Eric Van Cutsem, Kjell Öberg, and Marianne E Pavel
Somatostatin analogues (SSA) have demonstrated antiproliferative activity in addition to efficacy for carcinoid symptom control in functional neuroendocrine tumors (NET). A post hoc analysis of the placebo arm of the RAD001 In Advanced Neuroendocrine Tumors-2 (RADIANT-2) study was conducted to assess the efficacy of octreotide long-acting repeatable (LAR) on progression-free survival (PFS) and overall survival (OS) estimated using the Kaplan–Meier method. Out of 213 patients randomized to placebo plus octreotide LAR in RADIANT-2, 196 patients with foregut, midgut, or hindgut NET were considered for present analysis. Of these, 41 patients were SSA-treatment naïve and 155 had received SSA therapy before study entry. For SSA-naïve patients, median PFS by adjudicated central review was 13.6 (95% CI 8.2–22.7) months. For SSA-naïve patients with midgut NET (n=24), median PFS was 22.2 (95% CI 8.3–29.5) months. For patients who had received SSA previously, the median PFS was 11.1 (95% CI 8.4–14.3) months. Among the SSA-pretreated patients who had midgut NET (n=119), the median PFS was 12.0 (95% CI 8.4–19.3) months. Median OS was 35.8 (95% CI 32.5–48.9) months for patients in the placebo plus octreotide LAR arm; 50.6 (36.4 – not reached) months for SSA-naïve patients and 33.5 (95% CI 27.5–44.7) months for those who had received prior SSA. This post hoc analysis of the placebo arm of the large phase 3 RADIANT-2 study provides data on PFS and OS among patients with progressive NET treated with octreotide therapy.
Louis de Mestier, Anne Couvelard, Anela Blazevic, Olivia Hentic, Wouter W de Herder, Vinciane Rebours, Valérie Paradis, Philippe Ruszniewski, Leo J Hofland, and Jérôme Cros
The efficacy of alkylating agents (temozolomide, dacarbazine, streptozotocin) in patients with advanced neuroendocrine tumors (NETs) has been well documented, especially in pancreatic NETs. Alkylating agents transfer methyl adducts on DNA bases. Among them, O6-methylguanine accounts for many of their cytotoxic effects and can be repaired by the O6-methylguanine-methyltransferase (MGMT). However, whether the tumor MGMT status could be a reliable biomarker of efficacy of alkylating agents in NETs is still a matter of debate. Herein, we sought to provide a critical appraisal of the role of the MGMT status in NETs. After reviewing the molecular mechanisms of repair of DNA damage induced by alkylating agents, we aimed to comprehensively review the methods of determination of the MGMT status and its impact on prognosis, prediction of objective response and progression-free survival in patients with advanced digestive NETs treated by alkylating agents. About half of pancreatic NETs are MGMT-deficient, as determined by impaired tumor MGMT expression or by MGMT promoter methylation. Overall, while published studies are heterogeneous and mostly limited in size, they advocate that MGMT deficiency may be a relevant biomarker for increased objective response rate, prolonged progression-fee survival and overall survival in patients with advanced NETs treated by alkylating agents. While these data require confirmation in prospective controlled studies, future research should focus on the standardization of MGMT status assessment. Additional mechanisms of repair of DNA damages induced by alkylating agents should be explored in order to identify biomarkers complementary to MGMT and targets for potential antitumor synergy, such as PARP.
Martyn E Caplin, Marianne Pavel, Jarosław B Ćwikła, Alexandria T Phan, Markus Raderer, Eva Sedláčková, Guillaume Cadiot, Edward M Wolin, Jaume Capdevila, Lucy Wall, Guido Rindi, Alison Langley, Séverine Martinez, Edda Gomez-Panzani, Philippe Ruszniewski, and on behalf of the CLARINET Investigators
In the CLARINET study, lanreotide Autogel (depot in USA) significantly prolonged progression-free survival (PFS) in patients with metastatic pancreatic/intestinal neuroendocrine tumours (NETs). We report long-term safety and additional efficacy data from the open-label extension (OLE). Patients with metastatic grade 1/2 (Ki-67 ≤10%) non-functioning NET and documented baseline tumour-progression status received lanreotide Autogel 120 mg (n=101) or placebo (n=103) for 96 weeks or until death/progressive disease (PD) in CLARINET study. Patients with stable disease (SD) at core study end (lanreotide/placebo) or PD (placebo only) continued or switched to lanreotide in the OLE. In total, 88 patients (previously: lanreotide, n=41; placebo, n=47) participated: 38% had pancreatic, 39% midgut and 23% other/unknown primary tumours. Patients continuing lanreotide reported fewer adverse events (AEs) (all and treatment-related) during OLE than core study. Placebo-to-lanreotide switch patients reported similar AE rates in OLE and core studies, except more diarrhoea was considered treatment-related in OLE (overall diarrhoea unchanged). Median lanreotide PFS (core study randomisation to PD in core/OLE; n=101) was 32.8 months (95% CI: 30.9, 68.0). A sensitivity analysis, addressing potential selection bias by assuming that patients with SD on lanreotide in the core study and not entering the OLE (n=13) had PD 24 weeks after last core assessment, found median PFS remaining consistent: 30.8 months (95% CI: 30.0, 31.3). Median time to further PD after placebo-to-lanreotide switch (n=32) was 14.0 months (10.1; not reached). This OLE study suggests long-term treatment with lanreotide Autogel 120 mg maintained favourable safety/tolerability. CLARINET OLE data also provide new evidence of lanreotide anti-tumour benefits in indolent and progressive pancreatic/intestinal NETs.