Patients with neuroendocrine neoplasms (NENs) often require systemic treatment, which is frequently limited by the emergence of drug resistance. mTOR inhibitors (mTORi), such as RAD001 (everolimus), have been shown to inhibit neoplasm progression. mTORi stimulates autophagy, a degradation pathway that might promote the survival of neoplasm cells that are exposed to anti-cancer therapy. Chloroquine (CQ), a well-known anti-malarial and anti-rheumatic drug, suppresses autophagy. Based on our previous results, we hypothesized that CQ may enhance the anti-tumorigenic effects of mTORi by inhibiting autophagy and we aimed to examine the anti-tumorigenic effect of CQ, alone or in combination with RAD001. We established a NEN subcutaneous xenograft mouse model and evaluated the effect of the drugs on tumor growth, mTOR pathway, autophagy and apoptosis. CQ alone and in combination with RAD001 significantly decreased neoplasm volume. Histopathological analysis revealed that the combination of CQ and RAD001 markedly inhibited mTOR activity and neoplasm cell growth, along with accumulation of autophagosomes and increased apoptosis. In conclusion, CQ enhances the anti-tumorigenic effect of RAD001 in vivo by inhibiting autophagy. Clinical trials addressing the effects of CQ therapy on neoplasm progression in patients with NENs, mainly in those treated with mTORi, are warranted.

Imatinib mesylate (IM), a small molecule that is a selective inhibitor of the ABL, platelet derived growth factor receptor (PDGFR-R) and stem cell ligand receptor (c-kit) tyrosine kinases (TK). IM was also found to inhibit the TK activity of BCR/ABL fusion protein produced in chronic myelogenous leukemia, with marked clinical activity against the disease. Since both PDGF-R and c-kit both having a putative role in tumorigenesis, we investigated the efficacy and safety of the use of IM in patients with endocrine tumors unresponsive to conventional therapies that expressed c-kit and/or PDGF-R (within the framework of a comprehensive phase II multi-center study of IM in patients with solid tumors). IM was initiated at a dose of 400 mg/day, with possible dose escalation within 1 week to 600 mg/day and an option to raise the dose to 800 mg/day in the event of progression and in the absence of safety concerns for a period of up to 12 months. Between September 2002 and July 2003, 15 adult patients with disseminated endocrine tumors were recruited as follows: medullary thyroid carcinoma (MTC, n = 6); adrenocortical carcinoma (ACC, n = 4); malignant pheochromocytoma (pheo, n = 2); carcinoid (non-secreting, n = 2), neuroendocrine tumor (NET, n = 1). No objective responses were observed. MTC – disease progression in 4 patients, and treatment discontinuation in 2 patients due to adverse events; ACC – disease progression in 3 patients, and treatment discontinuation in 1 patient due to severe psychiatric adverse event; Pheo – disease progression in 2 patients; Carcinoid – stable disease in 1 patient (6.5 months), and disease progression in 1 patient; NET – disease progression in 1 patient. IM does not appear to be useful for treatment of malignant endocrine tumors, also causing significant toxicity in this patient population.

To investigate the activity of etoposide, doxorubicin, and cisplatin plus mitotane in the management of advanced adrenocortical carcinoma (ACC) patients, 72 patients with measurable disease not amenable to radical surgery were enrolled in a prospective, multicenter phase II trial. EDP schedule (etoposide 100 mg/m² on days 5–7, doxorubicin 20 mg/m² on days 1 and 8, and cisplatin 40 mg/m² on days 1 and 9) was administered intravenously every 4 weeks. Concomitantly, patients were given up to 4 g/day of oral mitotane. Five patients achieved a complete response and 30 a partial response, for an overall response rate of 48.6% (95% CI: 37.1–60.3). Median time to progression in responding patients was 18 months. The EDP regimen was well tolerated, leukopenia being the dose limiting toxicity. One toxic related death due to septic shock, however, was registered. Radical surgical resection of residual disease after chemotherapy was performed in 10 patients. The overall survival of patients attaining a disease free status (clinical complete responders+radically resected) was significantly higher than that of patients with partial response or no response (P<0.002). Androgen secretion was associated with long survival, while glucocorticoid secretion was associated with poor prognosis both in univariate and multivariate analysis. In conclusion, EDP plus mitotane is an active and manageable combination scheme for ACC patients. Surgical resection of residual disease subsequent to chemotherapy leads to a more favourable outcome. The natural history of the disease is significantly influenced by the secretory status of the tumor.

Telotristat ethyl, a tryptophan hydroxylase inhibitor, was efficacious and well tolerated in the phase 3 TELESTAR study in patients with carcinoid syndrome (CS) experiencing ≥4 bowel movements per day (BMs/day) while on somatostatin analogs (SSAs). TELECAST, a phase 3 companion study, assessed the safety and efficacy of telotristat ethyl in patients with CS (diarrhea, flushing, abdominal pain, nausea or elevated urinary 5-hydroxyindoleacetic acid (u5-HIAA)) with <4 BMs/day on SSAs (or ≥1 symptom or ≥4 BMs/day if not on SSAs) during a 12-week double-blind treatment period followed by a 36-week open-label extension (OLE). The primary safety and efficacy endpoints were incidence of treatment-emergent adverse events (TEAEs) and percent change from baseline in 24-h u5-HIAA at week 12. Patients (N = 76) were randomly assigned (1:1:1) to receive placebo or telotristat ethyl 250 mg or 500 mg 3 times per day (tid); 67 continued receiving telotristat ethyl 500 mg tid during the OLE. Through week 12, TEAEs were generally mild to moderate in severity; 5 (placebo), 1 (telotristat ethyl 250 mg) and 3 (telotristat ethyl 500 mg) patients experienced serious events, and the rate of TEAEs in the OLE was comparable. At week 12, significant reductions in u5-HIAA from baseline were observed, with Hodges–Lehmann estimators of median treatment differences from placebo of −54.0% (95% confidence limits, −85.0%, −25.1%, P < 0.001) and −89.7% (95% confidence limits, −113.1%, −63.9%, P < 0.001) for telotristat ethyl 250 mg and 500 mg. These results support the safety and efficacy of telotristat ethyl when added to SSAs in patients with CS diarrhea (ClinicalTrials.gov identifier: Nbib2063659).

We conducted a retrospective/prospective worldwide study on patients with neuroendocrine neoplasms (NENs) and a molecularly proven SARS-CoV-2 positivity. Preliminary results regarding 85 patients of the INTENSIVE study have been published in 2021. Now we are reporting the 2-year analysis.Here, we are reporting data from consecutive patients enrolled between 1 June 2020, and 31 May 2022. Among the 118 contacted centers, 25 were active to enroll and 19 actively recruiting at the time of data cut-off for a total of 280 patients enrolled. SARS-CoV-2 positivity occurred in 47.5% of patients in 2020, 35.1% in 2021, and 17.4% in 2022. The median age for COVID-19 diagnosis was 60 years. Well-differentiated tumors, non-functioning, metastatic stage, and gastroenteropancreatic (GEP) primary sites represented most of the NENs. COVID-19-related pneumonia occurred in 22.8% of the total, with 61.3% of them requiring hospitalization; 11 patients (3.9%) needed sub-intensive or intensive care unit therapies and 14 patients died (5%), in 11 cases (3.9%) directly related to COVID-19. Diabetes mellitus and age at COVID-19 diagnosis > 70 years were significantly associated with COVID-19 mortality, whereas thoracic primary site with COVID-19 morbidity. A significant decrease in both hospitalization and pneumonia occurred in 2022 vs 2020. In our largest series of NEN patients with COVID-19, the NEN population is similar to the general population of patients with NEN regardless of COVID-19. However, older age, non-GEP primary sites and diabetes mellitus should be carefully considered for increased COVID-19 morbidity and mortality. Relevant information could be derived by integrating our results with NENs patients included in other cancer patients with COVID-19 registries.