Clinical Activity of Selpercatinib in RET-mutant Pheochromocytoma

INTRODUCTION

Activating RET alterations have been reported in a variety of solid tumors, including pheochromocytoma where they occur both sporadically and as part of familial multiple endocrine neoplasia type 2 (MEN2) syndromes. Selpercatinib is a first-in-class, highly selective, and potent small molecule RET kinase inhibitor that has demonstrated marked and durable anti-tumor activity in diverse RET-activated solid tumors in the LIBRETTO-001 study (NCT03157128).

METHODS

We describe the first six pheochromocytoma cases treated with selpercatinib in the LIBRETTO-001 study.

RESULTS

Of the six patients (one sporadic and five reported as part of MEN2 syndromes) in this case report, four had a partial response/complete response and two had stable disease per independent review committee. Treatment duration ranged from 9.2 months to more than 56.4 months. The safety profile of treatment was consistent with selpercatinib in other indications.

CONCLUSION

These data support selpercatinib as an effective therapy against RET-mutant pheochromocytoma, adding to the diversity of RET-activated tumor types that may benefit from targeted RET inhibition.

Neoadjuvant dabrafenib and trametinib for functional organ preservation in recurrent BRAF V600E-mutated papillary thyroid cancer

OBJECTIVES

To describe the first reported use of neoadjuvant dabrafenib and trametinib specifically to permit organ conservation surgery in locally advanced recurrent differentiated thyroid carcinoma.

PATIENTS AND METHODS

A patient presented with locally recurrent, radioiodide-resistant DTC with a BRAF V600E mutation invading the laryngotrachea. Definitive treatment would require a total laryngectomy. She was offered neoadjuvant dabrafenib and trametinib prior to surgery.

RESULTS

A significant radiographic response permitted partial laryngectomy, enabling preservation of voice, early resumption of oral feeding, and avoidance of permanent tracheostomy. At 9 months, she remained free of disease.

CONCLUSION

Neoadjuvant tyrosine kinase inhibitor treatment prior to definitive surgery for locally-invasive recurrent DTC is a potential approach that may limit the degree of surgery and associated morbidity.

Coronary Artery and Peripheral Vascular Disease in a Patient with Poorly Differentiated Thyroid Cancer Treated with the Tyrosine Kinase Inhibitor Lenvatinib

A subset of patients with differentiated thyroid carcinoma develop radioiodine refractory (RAIR) incurable disease, which typically has a poor prognosis. The multitargeted tyrosine kinase inhibitor lenvatinib has demonstrated significant improvements in progression-free survival in RAIR thyroid cancers compared to placebos. However, in the phase III SELECT trial of the drug in thyroid cancer, 5.4% of patients on lenvatinib experienced arterial thromboembolic events, with 2.7% experiencing severe grade ≥3 toxicities associated with arterial vascular events. This case study reports a patient with metastatic poorly differentiated follicular thyroid cancer who developed significant obstructive coronary artery disease following initiation of lenvatinib treatment, despite no predisposing cardiovascular risk factors apart from a remote smoking history. The possibility of developing coronary or peripheral artery disease should be considered in patients who are on targeted therapies, such as lenvatinib, even in the absence of traditional cardiovascular risk factors. In addition, baseline cardiac risk assessment and early treatment should be pursued to minimize interruptions to potentially lifesaving cancer therapy.

Clinical Outcomes of DEB-TACE in Hepatic Metastatic Neuroendocrine Tumors: A 5-Year Single-Institutional Experience

RATIONALE AND OBJECTIVES

To evaluate single-institution outcomes of drug-eluting bead transarterial chemoembolization (DEB-TACE) in the treatment of locally advanced neuroendocrine tumor (NET) hepatic metastases with a focus on safety and efficacy of treatment.

MATERIALS AND METHODS

A single-center retrospective cohort study of the outcomes of consecutive patients with NELM who underwent DEB-TACE between 2014 and 2019 was performed. Clinicopathologic characteristics, radiologic response (modified Response Evaluation Criteria in Solid Tumors) at 1-month follow-up, adverse events, progression-free survival (PFS), and overall survival were calculated.

RESULTS

Among 287 patients (mean age of 62 years; 39% male: 61% female), disease burden was bilobar (90.2%) with mean largest tumor diameter measuring 4.9 ± 2.8 cm. Of these patients, 14.6% had no evidence of tumor in other organs or lymph nodes. Complete response occurred in 60 (20.9%) patients while 133 (46.3%) had partial responses. Major complication occurred in 2.4%. Liver function tests including total bilirubin and AST were overall stable at the 1-month follow-up, with only a small increase in the ALT at +8.9% (p < 0.01). Overall survival was 80.1% at 1 year, 49.1% at 3 years, and 12.3% at 5 years with a mean PFS of 14.4 ± 12.5 months.

CONCLUSION

Based on this institutional experience, DEB-TACE is an acceptable locoregional therapy choice for hepatic metastases of NET due to its tolerable safety profile and relative efficacy.

Selpercatinib for adult patients with locally advanced or metastatic RET-altered solid tumors

INTRODUCTION

The rearranged during transfection (RET) mutation is an oncogene driver for the development of cancer. Selpercatinib is a highly selective RET inhibitor that has demonstrated anti-tumor activity in RET-mutated cancers. Selpercatinib is approved for use in RET fusion-positive non-small-cell lung cancer (NSCLC), RET-mutated medullary thyroid cancer, RET fusion-positive thyroid cancer, and RET fusion-positive solid tumors.

AREAS COVERED

This review summarizes the pharmacology, efficacy, safety, and resistance mechanism of selpercatinib.

EXPERT OPINION

Selpercatinib has demonstrated durable responses with a favorable safety profile making it an excellent treatment option for RET-mutated cancers. Clinical trials are currently underway to determine the optimal sequencing of selpercatinib in RET fusion-positive lung and RET-mutated medullary thyroid cancer in the first-line setting compared to the current standard of care. Selpercatinib has shown promising anti-tumor activity in various RET-altered solid tumors opening a new treatment option for these patients.

A Phase II Clinical Trial of Nivolumab and Temozolomide for Neuroendocrine Neoplasms

PURPOSE

Treatment options are limited in patients with metastatic neuroendocrine neoplasms (NEN). We present the results for a phase II trial of combination nivolumab and temozolomide in patients with advanced NEN along with results of immune changes in peripheral blood.

PATIENTS AND METHODS

NCT03728361 is a nonrandomized, phase II study of nivolumab and temozolomide in patients with NEN. The primary endpoint was response rate using RECIST 1.1. Secondary endpoints included progression-free survival (PFS), overall survival (OS), and safety. Immune profiling was performed by mass cytometry to evaluate the effect on peripheral blood immune cell subsets.

RESULTS

Among all 28 patients with NEN, the confirmed response rate was 9/28 [32.1%, 95% confidence interval (CI): 15.9-52.4]. Of 11 patients with lung NEN, the response rate was 64% (n = 7); there was a significant difference in responses by primary tumor location (lung vs. others, P = 0.020). The median PFS was 8.8 months (95% CI: 3.9-11.1 months), and median OS was 32.3 months (95% CI: 20.7-not reached months). Exploratory blood immune cell profiling revealed an increase in circulating CD8+ T cells (27.9% ± 13.4% vs. 31.7% ± 14.6%, P = 0.03) and a decrease in CD4+ T cells (59.6% ± 13.1% vs. 56.5% ± 13.0%, P = 0.001) after 2 weeks of treatment. LAG-3-expressing total T cells were lower in patients experiencing a partial response (0.18% ± 0.24% vs. 0.83% ± 0.55%, P = 0.028). Myeloid-derived suppressor cell levels increased during the study and did not correlate with response.

CONCLUSIONS

Combination nivolumab and temozolomide demonstrated promising activity in NEN. See related commentary by Velez and Garon, p. 691.

Health-related quality-of-life analyses from a multicenter, randomized, double-blind phase 2 study of patients with differentiated thyroid cancer treated with lenvatinib 18 or 24 mg/day

BACKGROUND

In the phase 2 double-blind Study 211, a starting dose of lenvatinib 18 mg/day was compared with the approved starting dose of 24 mg/day in patients with radioiodine-refractory differentiated thyroid cancer (RR-DTC). Predefined criteria for noninferiority for efficacy in the 18 mg arm were not met; safety was similar in both arms. Impact of lenvatinib treatment on health-related quality-of-life (HRQoL) was a secondary endpoint of Study 211.

METHODS

Patients with RR-DTC were randomly assigned to a blinded starting dose of lenvatinib 18 mg/day or 24 mg/day. HRQoL was assessed at baseline, every 8 weeks until Week 24, then every 16 weeks, and at the off-treatment visit, using the EQ-5D-3L and FACT-G instruments. Completion and compliance rates, mean change from baseline, and times to first and definitive deterioration were evaluated.

RESULTS

Baseline EQ-5D and FACT-G scores, and overall changes from baseline, were comparable between patients in the lenvatinib 18 mg/day (n = 77) and 24 mg/day arms (n = 75). For the 18 mg versus 24 mg arms, least squares mean differences were -0.42 (95% CI -4.88, 4.03) for EQ-5D-VAS and 0.47 (95% CI -3.45, 4.39) for FACT-G total. Time to first deterioration did not significantly favor either arm; EQ-5D-VAS HR [18 mg/24 mg] 0.93 (95% CI 0.61-1.40), EQ-5D-HUI HR [18 mg/24 mg] 0.68 (95% CI 0.44-1.05), FACT-G total HR [18 mg/24 mg] 0.73 (95% CI 0.48-1.12). Time to definitive deterioration did not significantly favor either arm, though EQ-5D-VAS showed a trend in favor of the 24 mg arm (HR [18 mg/24 mg] 1.72; 95% CI 0.99-3.01); EQ-5D-HUI HR [18 mg/24 mg] was 0.96 (95% CI 0.57-1.63), FACT-G total HR [18 mg/24 mg] was 0.72 (95% CI 0.43-1.21).

CONCLUSIONS

In Study 211, HRQoL for patients in the lenvatinib 18 mg/day arm was not statistically different from that of patients in the 24 mg/day arm. These data further support the use of the approved lenvatinib starting dose of 24 mg/day in patients with RR-DTC.

CLINICALTRIALS

GOV NUMBER

NCT02702388.

Pharmacokinetics and RP2D analysis from ETCTN 10388: A phase I trial of triapine and lutetium Lu-177 dotatate in well-differentiated somatostatin receptor–positive gastroenteropancreatic neuroendocrine tumors (GEP-NETs)

648

Background: Radiation is a potent inducer of DNA double-strand breaks, and ribonucleotide reductase (RNR) is the rate-limiting enzyme for conversion of ribonucleoside diphosphate to deoxyribonucleotide diphosphate, and thus repair of DNA in this setting. ETCTN 10388 evaluated safety of combination Lu-177 DOTATATE, a beta-emitting radionuclide in combination with triapine, a ribonucleotide reductase (RNR) inhibitor. Methods: This investigator initiated, NCI sponsored, multicenter phase 1 trial, enrolled a total of 31 patients in the dose escalation [using the Bayesian optimal interval design (BOIN)] and dose expansion cohorts. Oral triapine was administered on days 1-14 and Lu-177 DOTATATE [200 mCi] intravenously on day 1 of every 56-day cycle. A total of 4 cycles were administered. All enrolled patients had blood samples collected for triapine pharmacokinetic (PK) analysis in EDTA tubes prior to and at 0.5, 1, 1.5, 2, 3, 4, 6, and 8 h after oral administration during cycle 1. Results: Five patients were enrolled in triapine Dose Level 1 (100 mg/day), twenty-five to dose level two (150 mg/day), and one patient to dose level three (200 mg/day). PK data were available for 12 patients enrolled in the dose escalation cohort. The geometric mean (SD) AUC0-inf was 1159 (1.22) µg/L•h for the 100mg dose level and 1862 (1.76) µg/L•h for the 150 mg dose level, suggesting that exposure increased with dose, and inter-patient variability was as expected for an oral agent. Triapine PK parameter values observed in this trial, were comparable to previous reports that used a previous formulation [ 1 ]. While exposure was similar, variability appeared smaller with the current oral formulation. Adverse events (AE) were assessed in all 31 patients per CTCAE 5.0. A total of one DLT in dose level 1, seven DLTs (Transient cytopenia; primarily neutropenia and rarely thrombocytopenia) in dose level 2, and one grade 5 DLT (Death probably from progressive cancer and carcinoid heart disease but possibly from trial drugs) in dose level 3 were observed. Detailed AE profile will be presented at the meeting. Conclusions: The RP2D of triapine is 150 mg QD on days 1-14 in combination with Lu-177 DOTATATE on day 1 of every 56-day cycle. Clinical trial information: 04234568 .

ETCTN 10450: A phase I trial of peposertib and lutetium 177 DOTATATE in well-differentiated somatostatin receptor-positive gastroenteropancreatic neuroendocrine tumors (GEP-NETs)

TPS658

Background: Radiolabeled somatostatin analogues provide a means of delivering targeted radiation with a high therapeutic index to NETs that express somatostatin receptors (SSTRs). Radiolabeled somatostatin analogue Lutetium 177 DOTATATE (Lutathera) is a beta-emitting radionuclide, FDA approved for use in SSTR positive gastroenteropancreatic neuroendocrine tumors (GEPNETS) in the US based on the NETTER-1 Phase III trial. Despite favorable PFS and safety profile, the drug has limited cytoreductive capability with a 17% ORR. Peptide receptor radionuclide therapy (PRRT) also doesn’t seem to be very effective in treating peritoneal disease. We hypothesize that addition of an effective radiation sensitizer could help improve antitumor activity of Lutathera. Radiation is a potent inducer of DNA double-strand break (DSB); targeting signaling networks involved in DSB repair is a promising approach for enhancing cellular radiosensitivity. The primary repair mechanism of radiation-induced DSBs is nonhomologous end-joining (NHEJ) pathway, in which the DNA-PK (Deoxyribonucleic acid protein kinase) complex plays a pivotal role. Upregulation of DNA-PK promotes repair of DSBs leading to tumor radio-resistance preclinically and clinically. Thus, DNA-PK is an important molecular target for inhibiting DSB repair and enhancing the cytotoxicity of radiation. Peposertib is a selective inhibitor of DNA-PK that targets tumor cell DNA damage repair and survival by blocking NHEJ. We previously reported strong anti-tumor activity when Peposertib was used as radiation sensitizer in pre-clinical NET models. Methods: This study is an investigator initiated, NCI sponsored, multicenter phase 1 trial of peposertib and Lutetium Lu 177 DOTATATE in well-differentiated somatostatin receptor-positive gastroenteropancreatic neuroendocrine tumor (GEP-NETs) after the failure of at least one line of prior systemic cancer treatment. A total of 29 patients will be enrolled in the dose escalation with help of Bayesian optimal interval design (BOIN) and dose expansion cohorts. The study will be open through the NCI ETCTN (National Cancer Institute Experimental Therapeutics Clinical Trials Network) program. Patients will be treated with 177 lutetium dotatate in combination with peposertib. Peposertib will be administered orally from D1-21 with each dose of PRRT [200 mCi]. Primary endpoint is to evaluate recommended phase II dose (RP2D). Secondary endpoints are to evaluate safety, pharmacokinetics, and clinical activity (ORR and PFS). We are also evaluating Lu-177 DOTATATE dosimetry in collaboration with NIH IROC and plasma hPG80, a novel blood based diagnostic biomarker. In addition, the study will correlate clinical outcome with somatic tumor mutations and germline mutations. Clinical trial information: 04750954 .

Kinase inhibitors in thyroid cancers

Objective

The treatment landscape for thyroid cancers has changed rapidly with the availability of kinase inhibitors against VEGFR, BRAF, MEK, NTRK, and RET. We provide an up-to-date review of the role of kinase inhibitors in thyroid cancer and discuss upcoming trials.

Design & Methods

A comprehensive review of the available literature describing kinase inhibitors in thyroid cancer was performed.

Results and Conclusions

Kinase inhibitors have become the standard of care for patients with metastatic radioactive iodine-refractory thyroid cancer. Short-term treatment can re-sensitize differentiated thyroid cancer to radioactive iodine, thereby potentially improving outcomes and sparing toxicities associated with the long-term use of kinase inhibitors. The approval of cabozantinib as salvage therapy for progressive radioactive iodine-refractory differentiated thyroid cancer following failure with sorafenib or lenvatinib adds to the available armamentarium of active agents. Vandetanib and cabozantinib have become mainstay treatments for metastatic medullary thyroid cancer regardless of RET mutation status. Selpercatinib and pralsetinib, potent and selective receptor kinase inhibitors with activity against RET, have revolutionized the treatment paradigm for medullary thyroid cancers and other cancers with driver mutations in RET. Dabrafenib plus trametinib for BRAF mutated anaplastic thyroid cancer provides an effective treatment option for this aggressive cancer with a dismal prognosis. In order to design the next generation of agents for thyroid cancer, future efforts will need to focus on developing a better understanding of the mechanisms of resistance to kinase inhibition including bypass signaling and escape mutations.

Dabrafenib Versus Dabrafenib + Trametinib in BRAF-Mutated Radioactive Iodine Refractory Differentiated Thyroid Cancer: Results of a Randomized, Phase 2, Open-Label Multicenter Trial

Background: Oncogenic BRAF mutations are commonly found in advanced differentiated thyroid cancer (DTC), and reports have shown efficacy of BRAF inhibitors in these tumors. We investigated the difference in response between dabrafenib monotherapy and dabrafenib + trametinib therapy in patients with BRAF-mutated radioactive iodine refractory DTC. Methods: In this open-label randomized phase 2 multicenter trial, patients aged ≥18 years with BRAF-mutated radioactive iodine refractory DTC with progressive disease by Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 within 13 months before enrollment were eligible. Patients were randomly assigned to receive dabrafenib alone or dabrafenib + trametinib. The primary endpoint was objective response rate by modified RECIST (minor response of -20% to -29%, partial and complete response) within the first 24 weeks of therapy. Trial Registration Number: NCT01723202. Results: A total of 53 patients were enrolled. The objective response rate (modified RECIST) was 42% (11/26 [95% confidence interval {CI} 23-63%]) with dabrafenib versus 48% (13/27 [CI 29-68%]) with dabrafenib + trametinib (p = 0.67). Objective response rate (RECIST 1.1) was 35% (9/26 [CI 17-56%]) with dabrafenib and 30% (8/27 [CI 14-51%]) with dabrafenib + trametinib. Most common treatment-related adverse events included skin and subcutaneous tissue disorders (17/26, 65%), fever (13/26, 50%), hyperglycemia (12/26, 46%) with dabrafenib alone and fever (16/27, 59%), nausea, chills, fatigue (14/27, 52% each) with dabrafenib + trametinib. There were no treatment-related deaths. Conclusions: Combination dabrafenib + trametinib was not superior in efficacy compared to dabrafenib monotherapy in patients with BRAF-mutated radioiodine refractory progressive DTC.

An Evaluation of Clinical Efficacy of Immune Checkpoint Inhibitors for Patients with Anaplastic Thyroid Carcinoma

Background: Anaplastic thyroid carcinoma (ATC) is an aggressive thyroid malignancy that is associated with poor prognosis. Current treatment options include surgery, radiation, cytotoxic chemotherapy, and multikinase inhibitor therapy. The role of immunotherapy in ATC is an area of active interest and recent evidence suggests that it may be a potentially effective treatment option. Methods: We report a case series of 13 patients with locally advanced or metastatic unresectable ATC who received immune checkpoint inhibitor therapy (pembrolizumab or nivolumab) at a single institution. Results: The patients' median age was 70 years, 54% (7/13) were male, and 85% (11/13) had stage IVC disease with lungs and lymph nodes being the most common sites of metastases. Ten patients had tumor tissue available for programmed death-ligand 1 (PD-L1) expression testing, all of which were positive for PD-L1, and seven of these patients also had a BRAF^V600E mutation. The median progression-free survival was 1.9 months and median overall survival (OS) was 4.4 months. The objective response rate was 16% (2/13). Two patients had partial response (PR), and three patients had durable stable disease. Among patients with a clinical benefit, after a median follow-up of 13.5 months, median OS had not been reached (range 4+ to 29+ months). Responses were ongoing in four subjects. The one-year survival rate was 38% (5/13). Six patients (46%) experienced an immune-related adverse event, and 15% (2/13) experienced a grade 3 or higher adverse event, including one patient with grade 5 immune checkpoint-related thyroiditis. Conclusions: Immune checkpoint blockade was well tolerated with a toxicity profile consistent with published literature on PD-1/PD-L1-targeting therapies. For ATC patients, immune checkpoint inhibition may represent an effective treatment option with robust sustained responses seen in a subset of patients.

Tumor agnostic efficacy of selpercatinib in patients with RET fusion+ solid tumors: A global, multicenter, registrational trial update (LIBRETTO-001)

3094

Background: Selpercatinib, a first-in-class highly selective and potent RET kinase inhibitor, is approved in multiple countries for the treatment of lung and thyroid cancer with RET fusions and medullary thyroid cancer with RET mutations. We provide an efficacy and safety update with more patients (pts) and longer follow-up (data cut-off: 24Sep2021) in RET fusion+ solid tumors with histologies other than lung/thyroid. Methods: The phase 1/2 LIBRETTO-001 trial (NCT03157128) enrolled pts with locally advanced/metastatic RET fusion+ solid tumors. Following dose escalation, pts received the recommended dose of 160 mg orally twice daily. The efficacy analysis set consisted of pts enrolled ≥6 months (mo) prior to the cut-off date. If a pt achieved response, an additional ≥6 mo follow-up from the initial response was required. There was no additional follow-up required for non-responders. Response was assessed per RECIST 1.1. Primary endpoint was objective response rate (ORR) by independent review committee (IRC). Secondary endpoints included ORR by investigator (INV), duration of response (DoR), progression-free survival (PFS), time to response (TTR), and safety. Results: Forty-five pts with 14 unique RET fusion+ tumor types received ≥1 dose of selpercatinib: 12 pancreatic, 10 colon, 4 salivary, 3 unknown primary, 3 sarcoma, 2 each of breast, carcinoma of the skin, xanthogranuloma, and cholangiocarcinoma, and 1 each of lung carcinoid, rectal neuroendocrine, small intestine, ovarian, and pulmonary carcinosarcoma. Median age was 53 years (range 21-85). Forty-one pts received prior systemic therapy (median prior lines: 2, range 0-9); 31% received ≥3 lines. In 41 efficacy-evaluable pts, confirmed ORR by IRC was 44% (18/41, 95% CI: 29-60). Clinical benefit was observed in 63% (26/41) of pts: 2 complete responses (breast, small intestine), 16 partial responses, and stable disease ≥16 weeks in 8 pts by IRC. Responses were observed across a variety of fusion partners. Median TTR was 1.9 mo by IRC. Median DoR was 24.5 mo (95% CI: 9.2-NE) with 50% (9/18) of responses ongoing at a median follow-up of 14.9 mo by IRC. Median PFS by IRC was 13.2 mo (95% CI: 7.4-26.2), with 34.1% alive and progression-free at a median follow-up of 16.4 mo. No new safety signals were identified in this cohort compared to broader safety database. Three grade 5 AEs were observed (unrelated to treatment by INV), and 4 pts discontinued treatment due to AEs (1 deemed related to treatment by INV). Conclusions: Selpercatinib continued to demonstrate durable antitumor activity in pts with RET fusion+ cancers across multiple tumor types. No new safety signals were identified. These results emphasize the importance of comprehensive genomic profiling to identify actionable oncogenic drivers, including RET fusions. The LIBRETTO-001 study continues to enroll pts. Clinical trial information: NCT03157128.

Randomized phase II study of platinum and etoposide (EP) versus temozolomide and capecitabine (CAPTEM) in patients (pts) with advanced G3 non-small cell gastroenteropancreatic neuroendocrine neoplasms (GEPNENs): ECOG-ACRIN EA2142

4020

Background: High grade (G3) GEPNENs are a rare and heterogeneous disease entity for which there is little prospective treatment data. EP chemotherapy is the treatment standard but this may not be appropriate for all G3 GEPNEN pts. CAPTEM has demonstrated activity in G3 GEPNENs and may be a promising alternative. EA2142 aimed to determine if CAPTEM was superior to EP in pts with G3 GEPNENs. Methods: This was a multicenter, randomized (1:1) phase II trial for pts with a locally advanced and unresectable or metastatic well differentiated G3 neuroendocrine tumor (NET) or a poorly differentiated, non-small cell G3 neuroendocrine carcinoma (NEC) of suspected gastrointestinal origin and an ECOG PS of 0-2. Pathology must have demonstrated a Ki-67 of 20-100% or at least 10 mitoses/10 high powered field. Pts were randomized to receive capecitabine 750 mg/m2 orally every 12 hours on days 1-14 and temozolomide 200 mg/m2 orally once daily on days 10-14 of a 28-day treatment cycle (Arm A) or etoposide 100 mg/m2 daily on days 1-3 with either cisplatin 25 mg/m2 daily on days 1-3 or carboplatin AUC 5 on day 1 of a 21-day treatment cycle (Arm B). Restaging scans were performed every 8 weeks and toxicity monitored per CTCAEv4. Final statistical plan was to accrue 80 pts to detect a 67% improvement in progression free survival (PFS) (primary endpoint) with CAPTEM as compared to EP, 80% power and one-sided significance level of 0.10. A planned interim analysis for efficacy and futility was conducted. Results: A total of 67 pts were enrolled (Arm A, n=32; Arm B, n=35). Male 58%, African American 4%, Asian 3%. Mean age 61. Among 63 eligible pts, primary tumor site pancreatic 56%, non-pancreatic 43%. Poorly differentiated 57%, well differentiated 33%, unknown 10%. Mean Ki-67 48% (Arm A), 60% (Arm B). The study was closed prior to full accrual due to futility at 57.7% information time. In the interim analysis, among 62 eligible pts, PFS, overall survival and response rate with CAPTEM were 2.43 months (mos) (95% CI 2.04, 7.72), 12.6 mos, 9% respectively vs 5.36 mos (95% CI 2.14, 7.23), 13.6 mos and 10% with EP. Toxicity was evaluable in 57 pts with Grade (G) 3/4 events occurring in 29% of pts on Arm A, 66% of pts on Arm B. G3/4 events occurring in more than 5% of pts on Arm A—febrile neutropenia (n=2); abdominal pain (n=2); diarrhea (n=2); nausea (n=2); neutropenia (n=2); dehydration (n=2) and on Arm B—anemia (n=8); febrile neutropenia (n=2); fatigue (n=2); lymphopenia (n=2); neutropenia (n=12); thrombocytopenia (n=4); leukopenia (n=6). There was one G5 event on Arm A due to sepsis. Conclusions: CAPTEM does not appear to be superior to EP chemotherapy as front-line treatment for pts with G3 NENs but does demonstrate a more favorable toxicity profile. Studies assessing G3 NET independently of G3 NEC are needed. Clinical trial information: NCT02595424.

Efficacy of nivolumab and temozolomide in advanced neuroendocrine neoplasms (NENs) in a phase 2 clinical trial

4121

Background: Treatment options are limited in patients with metastatic NEN. Temozolomide (TEM) alone and in combination with capecitabine is active in NEN and has been shown to have immunomodulatory impact. Here we present the final results for the NEN cohort of a phase 2 trial of combination nivolumab and TEM in patients with advanced NEN along with observed peripheral immune changes. Methods: NCT03728361 is a non-randomized, two-cohort, open-label phase 2 trial of nivolumab and TEM in patients with metastatic NEN and small cell lung cancer. The NEN cohort enrolled patients with tumors of any WHO grade, location, and line of therapy; all patients had evidence of progression prior to study. Prior immunotherapy was not allowed. Treatment consisted of nivolumab 480 mg IV on day 1 and TEM 150 mg/m2 on days 1-5 of a 28-day cycle. The primary objective was efficacy measured as response rate (RR) by RECIST v1.1. Secondary objectives were progression free survival (PFS) and overall survival (OS), by the method of Kaplan–Meier. The translational objective was to analyze peripheral blood mononuclear cells (PBMCs) collected at screening (baseline) and on cycle 1, day 15 (C1D15) via mass cytometry. Results: The RR was 36% (n=10/28, 95% CI: 18.6%-55.9%), including 10 patients (36%) with PR, 16 (57%) with SD, and 2 (7%) with PD (Table). The disease control rate was 93%. Responses occurred across all WHO grades; 44% of patients with tumors with Ki-67 >20% had PR. There was a significant difference in ORR by primary tumor location (bronchial vs pancreas vs other, p=0.004). There was no significant difference in response by Ki-67% (p=0.872), or in patients treated as first line (31%) or beyond (40%, p=0.706). The median PFS was 8.9 months (95% CI: 3.9 – 11.1 months), and median OS was not reached (95% CI: 20.7 – NR months). Two immune related SAE’s occurred: myocarditis and diarrhea in one patient each; gr4 toxicities included neutropenia (10%) and thrombocytopenia (7%). Profiling of PBMCs revealed no correlation of baseline MDSC levels with clinical benefit, however significant changes within the T cell landscape, including a decrease in CD4+ T cells (59.6% ±13.08 vs. 56.5% ±13.01, p=0.001) and increase in CD8+ T cells (27.9% ±13.36 vs. 31.7% ±14.57, p=0.03) were observed. Conclusions: Combination nivolumab and TEM demonstrated promising efficacy in patients with NENs; median OS has not been reached. Clinical trial information: NCT03728361. [Table: see text]

Association of LAG-3 expression in circulating T cells and response to combination temozolomide (TMZ) and nivolumab (NIVO) in advanced neuroendocrine neoplasms (NENs): Results from an investigator-initiated phase 2 trial

4123

Background: LAG-3 is an immune checkpoint present on NK cells, activated T cells and myeloid cells that inhibit T cell responses. Recent evidence demonstrating the safety and efficacy of LAG-3 inhibition has increased interest in this pathway for the treatment of multiple malignancies but the role in NEN is unclear. We present results from correlative peripheral blood mass cytometry (CyTOF) performed in a phase 2 trial (NCT03728361) of the combination of NIVO and TMZ in pts with advanced NEN. Methods: Patients (pts) with progressive NEN of any grade or primary location and any line of therapy were eligible. Small cell lung cancer was excluded. Clinical results from NCT03728361 will be presented in a separate abstract. Study treatment consisted of NIVO 480 mg IV every 4 weeks and TMZ 150 mg/m2 for 5 consecutive days out of a 28-day cycle. Peripheral blood mononuclear cells (PBMCs) were available from 16 out of 28 patients at screening (baseline) and cycle 1, day 15 (C1D15) and analyzed via CyTOF. Antibody labelling was performed using a 37 marker Maxpar Direct Immune Profiling Assay (Fluidigm). Immune cell populations were compared using two sample t-tests between pts with partial response (PR) and non-partial response (non-PR). Results: At screening, no differences were observed in PD-1, TIM3, or KLRG1 positive T-cell populations between pts with PR or non-PR. Patients with a PR had a significantly lower % of LAG-3 expressing T cells (p=0.029). There was a trend towards a lower % CD8+LAG-3+ T cells in pts with PR (p=0.086). At C1D15: The % of CD8+ LAG-3+ T cells were significantly higher in PRs vs. non-PR (p = 0.015). In matched samples comparing T cell populations at screening to C1D15, LAG-3+ CD8+ T cells increased significantly in PRs when compared to non-PRs (p=0.021). Conclusions: The % of LAG-3+ T cell population at baseline associates with non-response to TMZ/NIVO in NENs. Among responders, there was a significant increase in CD8+ LAG-3+ T cells by Day 15 compared to baseline indicating a potential mechanism of immune escape and eventual resistance. Clinical trial information: NCT03728361. [Table: see text]

A Randomized Study of Lenvatinib 18 mg vs 24 mg in Patients With Radioiodine-Refractory Differentiated Thyroid Cancer

BACKGROUND

Lenvatinib is a multikinase inhibitor approved to treat radioiodine-refractory differentiated thyroid cancer (RR-DTC) at a starting dose of 24 mg/day. This study explored, in a double-blinded fashion, whether a starting dose of 18 mg/day would provide comparable efficacy with reduced toxicity.

METHODS

Patients with RR-DTC were randomized to lenvatinib 24 mg/day or 18 mg/day. The primary efficacy endpoint was objective response rate as of week 24 (ORRwk24); the odds ratio noninferiority margin was 0.4. The primary safety endpoint was frequency of grade ≥3 treatment-emergent adverse events (TEAEs) as of week 24. Tumors were assessed using RECIST v1.1. TEAEs were monitored and recorded.

RESULTS

The ORRwk24 was 57.3% (95% CI 46.1, 68.5) in the lenvatinib 24-mg arm and 40.3% (95% CI 29.3, 51.2) in the lenvatinib 18-mg arm, with an odds ratio (18/24 mg) of 0.50 (95% CI 0.26, 0.96). As of week 24, the rates of TEAEs grade ≥3 were 61.3% in the lenvatinib 24-mg arm and 57.1% in the lenvatinib 18-mg arm, a difference of -4.2% (95% CI -19.8, 11.4).

CONCLUSION

A starting dose of lenvatinib 18 mg/day did not demonstrate noninferiority compared to a starting dose of 24 mg/day as assessed by ORRwk24 in patients with RR-DTC. The results represent a clinically meaningful difference in ORRwk24. The safety profile was comparable, with no clinically relevant difference between arms. These results support the continued use of the approved starting dose of lenvatinib 24 mg/day in patients with RR-DTC and adjusting the dose as necessary.

Abstract CT011: Efficacy and safety of selpercatinib in RET fusion-positive cancers other than lung or thyroid cancers

Introduction: Selpercatinib, a first-in-class highly selective and potent RET kinase inhibitor, is approved in multiple countries for the treatment of RET fusion-positive lung or thyroid cancers. RET fusions are also implicated in the pathogenesis of other cancers. Selpercatinib's efficacy and safety were thus explored in patients (pts) with RET fusion-positive non-lung/non-thyroid cancers in a global, multicenter, registrational trial. Methods: Adults with locally advanced or metastatic RET fusion-positive non-lung/non-thyroid solid tumors enrolled in the phase 1/2 LIBRETTO-001 trial (NCT03157128) were included in this analysis (data cut-off: 19 March 2021). Following dose escalation, pts received the recommended dose of 160 mg orally, twice daily. Pts enrolled long enough to allow 6-month follow-up from their first dose comprised the efficacy-evaluable population. Response was assessed (RECIST 1.1) by investigators. The primary endpoint was objective response rate (ORR). Secondary endpoints included duration of response (DoR), time to response, and safety. Results: Thirty-two pts with RET fusion-positive non-lung/non-thyroid cancers included 12 unique tumor types: 9 pancreatic, 9 colon, 2 each of breast, salivary, sarcoma, and unknown primary, and 1 each of carcinoid, rectal neuroendocrine, small intestine, xanthogranuloma, ovarian, and pulmonary carcinosarcoma. The median age was 48 years (range 22-85). Twenty-nine pts received prior systemic therapy (median prior lines: 2, range 0-9). The ORR was 47% (N=15/32, 95% CI: 29-65). Objective responses were observed in 9 unique cancer types including colon, pancreatic, carcinoid, small intestine, salivary, xanthogranuloma, breast, ovarian, and sarcoma, and 5 additional patients had stable disease lasting ≥ 16 weeks. Median time to response was 1.9 months (range 0.7-7.3). Median DoR was not reached (median follow-up time of 13 months). Responses were ongoing in 73% (11/15) of pts. Safety among this population was consistent with the overall selpercatinib safety database. No patients in this cohort discontinued due to treatment-related AEs. Conclusion: Selpercatinib demonstrated promising antitumor activity in RET fusion-positive non-lung/non-thyroid cancers, including multiple treatment-refractory GI malignancies. Broad-based genomic profiling is essential to identify actionable oncogenic drivers, including RET fusions. The safety and efficacy of selpercatinib will continue to be explored in pts with these cancers in the ongoing LIBRETTO-001 study.

Citation Format: Vivek Subbiah, Bhavana Konda, Todd Bauer, Caroline McCoach, Gerald Falchook, Masayuki Takeda, Jyoti Patel, Jared Weiss, Nir Peled, Lyudmila Bazhenova, Victoria Soldatenkova, Pearl French, Nora Drove, Oliver Gautschi, Alexander Drilon. Efficacy and safety of selpercatinib in RET fusion-positive cancers other than lung or thyroid cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT011.

Randomized phase II study of sorafenib with or without everolimus in patients with radioactive iodine refractory Hürthle cell thyroid cancer (HCC) (Alliance A091302/ ITOG 1706)

6076

Background: HCC is a rare subtype of follicular cell thyroid cancer that has been poorly studied in the past. Recent genomic studies have shown the PI3K/Akt/mTOR pathway is frequently altered in HCC. In addition, a phase II study of sorafenib (S) and everolimus (E) showed promising data in HCC. A study to evaluate this was initiated through Alliance and the International Thyroid Oncology Group. Methods: Patients (pts) were randomized to either sorafenib and everolimus (SE) vs. sorafenib alone (S). Inclusion criteria included; (1) diagnosis of HCC (confirmed through central review), no prior S or E, refractory to radioactive iodine, progressive disease by RECIST over prior 14 months. Primary endpoint was a comparison of progression-free survival (PFS) between SE and S using a stratified 1-sided log-rank test with 0.20 significance level and a power of 80%. 28 events were needed at final analysis. Secondary endpoints consisted of overall survival (OS), confirmed response rate (RR), and adverse events. Results: 35 pts were randomized from 10/2014 to 9/2019, 34 of which were evaluable for analysis (17-SE; 17-S) because 1 patient cancelled prior to receiving treatment. Median age was 66.5 years and 74% were male. ECOG performance status (PS) was 0 (47%) and PS 1 (53%). 41% had prior systemic treatment for HCC. No significant differences in baseline characteristics were observed between treatment arms. Median follow-up in 22 alive patients was 39.2 months (range: 15.1-64.9). Seven (21%) patients remain on treatment. PFS was significantly improved in the SE arm as compared to the S arm (HR=0.65 (95% CI: 0.26, 1.57); median PFS: SE=24.7 months (95% CI: 6.1-no upper), S=10.9 months (95% CI: 5.5-no upper); stratified 1-sided p=0.1662). OS was similar between the arms (2-sided p=0.4138). Confirmed response rate was similar between arms as well (SE: 18% (3 partial response (PR) vs. S: 24% (3 PR, 1 complete response)); Fisher’s exact p=1.00). Grade 3 adverse event (AE) rates (regardless of attribution) were similar between arms (SE: 77% vs. S: 77%; p=1.00). Each arm had 1 patient with at least one grade 4 AE (SE patient: cardiac arrest, tracheal obstruction, encephalopathy; S patient: mucositis oral) and no grade 5 AEs. Conclusions: PFS was improved with the addition of E to S in this small randomized multi-institutional phase II study done. Accrual was difficult, but these promising results suggest that this combination should be further studied. Support: U10CA180821, U10CA180882, U24CA196171; https://acknowledgments.alliancefound.org ; Novartis/GSK; ClinicalTrials.gov Identifier: NCT02143726. Clinical trial information: NCT02143726.

Clinical Activity of Selpercatinib in RET Mutant Pheochromocytoma-Case Reports

Activating RET gene alterations have been reported in solid tumors including the rare cancer, pheochromocytoma (PHEO) found sporadically and in familial multiple endocrine neoplasia type 2 (MEN2) syndromes. Selpercatinib is a highly selective and potent small molecule RET kinase inhibitor that has demonstrated marked and durable anti-tumor activity in diverse RET-altered solid tumors. Described are the initial 3 PHEO patients treated with selpercatinib (LIBRETTO-001/NCT03157128). Case 1: 70-year-old white male with MEN2A and a history of medullary thyroid cancer (MTC) and PHEO s/p thyroidectomy and adrenalectomy, received MIBG in 1991 and 2016 due to symptom reoccurrence. Progressive metastatic disease associated with severe hypertension was treated with Lutate in 2017 and germline RET mutation p.Cys634Phe was confirmed. After developing severe back pain due to a T6 vertebral metastasis, he began selpercatinib treatment. As of Mar 2020, he has a partial response (PR) as assessed by investigator; his back pain resolved, normetanephrine and metanephrine levels decreased, and has ceased alpha and beta blockers. He remains on treatment with only grade 1-2 adverse events, none requiring interruption or dose modification. Case 2: 51-year-old white female with MEN2A and history of MTC and PHEO s/p thyroidectomy and adrenalectomy in 2010. She developed metastatic PHEO in 2013, with multiple bone, omentum, lung, liver, and spleen metastases. Between 2013 and 2018 she was treated with multiple courses of radiation and, additional surgical resections; a PR with sunitinib lasted 13 months followed by temozolomide/capecitabine treatment. A bone lesion biopsy in 2018 confirmed RET C618S mutation and with her disease progression and uncontrolled bone pain, she began selpercatinib treatment, experiencing a PR. After 5.5 months in the study, she discontinued treatment due to disease progression. Case 3: 45-year-old African American female diagnosed with sporadic PHEO in 1996, s/p multiple surgical resections. She received 2 cycles of cyclophosphamide/vincristine/dacarbazine without clinical benefit. I-131-MIBG therapy with autologous stem cell rescue in 2017 improved blood pressure, palpitations, and flushing but without tumor shrinkage while abdominal pain persisted. Somatic M918T RET-mutation was confirmed, and she began selpercatinib treatment in 2018 with symptom resolution and improved plasma metanephrine levels. She required dose reduction for grade 3 palmar-plantar erthrodysesthesia and had stable disease for 22 months until a new bone metastasis was identified. Due to ongoing clinical benefit, she remains on treatment despite disease progression. Conclusion: These are the initial reports of RET-mutant PHEO patients treated with selpercatinib adding to the diversity of RET-altered tumor types that may benefit from a selective RET inhibitor.

Emerging drugs for the treatment of adrenocortical carcinoma

Introduction: Adrenocortical cancer (ACC) is a rare and aggressive disease with a median survival of 14-17 months and 5-year survival of around 20% for advanced disease. Emerging evidence of sub-groups of ACC with specific molecular drivers indicate ACC may be amenable to inhibition of receptor tyrosine kinases involved in growth and angiogenic signaling. A significant subset of patients may also be responsive to immune strategies.Areas covered: This review outlines approaches of targeting upregulated growth pathways including Insulin-like Growth Factor, Vascular Endothelial Growth Factor, Fibroblast Growth Factor and Epidermal Growth Factor Receptor in ACC. Data of immune checkpoint blockade with nivolumab, ipilimumab, pembrolizumab and avelumab is explored in detail. Genomic studies indicate that up to 40% of ACC are driven by dysregulated WNT and glucocorticoid signaling, special focus is placed on emerging drugs in these pathways.Expert opinion: Progress in the treatment of ACC has faced challenges stemming from the rarity of the disease. Given recent advances in the understanding of the molecular pathogenesis of ACC, a window of opportunity has now opened to make significant progress in developing therapeutic options that target key pathways such as excessive glucocorticoid signaling, WNT signaling, cell cycle and immune checkpoints.

A phase II basket trial of Dual Anti-CTLA-4 and Anti-PD-1 Blockade in Rare Tumors (DART) SWOG S1609: High-grade neuroendocrine neoplasm cohort

BACKGROUND

The authors previously reported the results of the nonpancreatic neuroendocrine neoplasm cohort of the SWOG S1609 DART (Dual Anti-CTLA-4 and Anti-PD-1 Blockade in Rare Tumors) trial, which permitted all histologic grades and had a 44% overall response rate (ORR) among patients with high-grade disease. Here they sought to validate their findings in a dedicated prospective cohort of high-grade neuroendocrine neoplasms within S1609.

METHODS

A prospective, open-label, multicenter, phase 2 clinical trial of ipilimumab plus nivolumab was conducted across multiple rare tumor cohorts. The dedicated, high-grade neuroendocrine neoplasm cohort was examined here. The primary end point was the ORR according to version 1.1 of the Response Evaluation Criteria in Solid Tumors. Secondary end points included progression-free survival (PFS), overall survival (OS), and toxicity.

RESULTS

Nineteen patients with high-grade neuroendocrine neoplasms (defined by local pathology review) were enrolled in this cohort of S1609. The most common primary sites were unknown primaries (21%), which were followed by the rectum, gastroesophageal junction, cervix, and pancreas (11%). The median number of lines of prior therapy was 1 (range, 0-3). All patients were microsatellite-stable. The median Ki-67 value was 80%. The ORR was 26% (95% confidence interval [CI], 11%-45%), and the clinical benefit rate (stable disease for ≥6 months plus partial responses plus complete responses) was 32% (95% CI, 13%-57%). The 6-month PFS rate was 32% (95% CI, 16%-61%) with a median PFS of 2.0 months (95% CI, 1.8 months to ∞) and a median OS of 8.7 months (95% CI, 6.1 months to ∞). The most common toxicities were fatigue (32%) and rash (26%), and the most common grade 3/4 immune-related adverse event was rash (15%); there were no events that required treatment discontinuation and no grade 5 events.

CONCLUSIONS

Ipilimumab plus nivolumab demonstrated a 26% ORR in patients with high-grade neuroendocrine neoplasms, with durable responses seen in patients with refractory disease.

Co-occurrence of multiple endocrine neoplasia type 4 and spinal neurofibromatosis: a case report

Multiple Endocrine Neoplasia (MEN) type 4 is a rare genetic condition that results from variants of the CDKN1B gene and predisposes individuals to develop endocrine tumors. Spinal neurofibromatosis (SNF) is an uncommon subtype of neurofibromatosis type 1 (NF1) characterized by bilateral neurofibromas of all spinal roots. Here we report a case of the co-occurrence of these syndromes, which has not yet been described in the literature. A male in his 60s presented with Gleason 5 + 4 localized prostate adenocarcinoma treated with radical prostatectomy. Two years later, he developed liver and bone metastasis consistent with trans-differentiation into small cell carcinoma. He developed hypercalcemia due to primary hyperparathyroidism from a parathyroid adenoma treated surgically. His family history was significant for a first-degree relative with a clinical diagnosis of NF1 and several second-degree relatives with multiple café-au-lait macules. Spine MRI showed multiple bilateral neurofibromas. Germline genetic testing showed a pathogenic variant in the CDKN1B gene, a variant in the NF1 gene, and a normal MEN1 gene. In this rare case of MEN4 and SNF, the patient was asymptomatic for much of his life. In addition to parathyroid adenoma and spinal neurofibromas, he had prostate adenocarcinoma with trans-differentiation into metastatic small cell cancer. Whether this diagnosis was coincidental or related to an emerging phenotype remains to be elucidated.

KRAS G12V Mutation in Acquired Resistance to Combined BRAF and MEK Inhibition in Papillary Thyroid Cancer

BRAF V600E mutations occur in approximately 40% of all patients with papillary thyroid cancer (PTC) and are associated with a worse prognosis in population studies. Treatment with single-agent BRAF inhibitors can result in nondurable partial responses (PRs) in clinical trials, but resistance inevitably develops. The mechanisms of resistance are not completely understood, but in non-thyroid tumors harboring BRAF V600E mutations, resistance has been ascribed to concurrent or acquired mutations in MEK1/2, RAC1, KRAS, and NRAS. This case report describes a patient with radioactive iodine-refractory metastatic PTC treated in a clinical trial with combination BRAF and MEK inhibition who achieved a durable PR. At time of progression, biopsy revealed an acquired KRAS G12V-activating mutation. The patient subsequently went on to have a PR to cabozantinib therapy in the clinical trial. This is the first reported case of an acquired KRAS-activating mutation that developed during treatment with BRAF and MEK inhibition in a patient with BRAF-mutated PTC. The KRAS mutation was also detected in peripheral blood samples taken as part of the trial, indicating that resistant mutations may be identified through noninvasive means. The identification of resistant mutations in patients at time of progression is necessary to identify possible therapeutic options including potential clinical trials.ClinicalTrials.gov identifier: NCT01723202.

Neuroendocrine liver metastases: a contemporary review of treatment strategies

Well-differentiated neuroendocrine tumors (NETs) are globally increasing in prevalence and the liver is the most common site of metastasis. Neuroendocrine liver metastases (NELM) are heterogeneous in clinical presentation and prognosis. Fortunately, recent advances in diagnostic techniques and therapeutic strategies have improved the multidisciplinary management of this challenging condition. When feasible, surgical resection of NELM offers the best long-term outcomes. General indications for hepatic resection include performance status acceptable for major liver surgery, grade 1 or 2 tumors, absence of extrahepatic disease, adequate size and function of future liver remnant, and feasibility of resecting >90% of metastases. Adjunct therapies including concomitant liver ablation are generally safe when used appropriately and may expand the number of patients eligible for surgery. Among patients with synchronous resectable NELM, resection of the primary either in a staged or combined fashion is recommended. For patients who are not surgical candidates, liver-directed therapies such as transarterial embolization, chemoembolization, and radioembolization can provide locoregional control and improve symptoms of carcinoid syndrome. Multiple systemic therapy options also exist for patients with advanced or progressive disease. Ongoing research efforts are needed to identify novel biomarkers that will define the optimal indications for and sequencing of treatments to be delivered in a personalized fashion.

Direct exposure to SARS-CoV-2 and cigarette smoke increases infection severity and alters the stem cell-derived airway repair response

Most demographic studies are now associating current smoking status with increased risk of severe COVID-19 and mortality from the disease but there remain many questions about how direct cigarette smoke exposure affects SARS-CoV-2 airway cell infection. We directly exposed mucociliary air-liquid interface (ALI) cultures derived from primary human nonsmoker airway basal stem cells (ABSCs) to short term cigarette smoke and infected them with live SARS-CoV-2. We found an increase in the number of infected airway cells after cigarette smoke exposure as well as an increased number of apoptotic cells. Cigarette smoke exposure alone caused airway injury that resulted in an increased number of ABSCs, which proliferate to repair the airway. But we found that acute SARS-CoV-2 infection or the combination of exposure to cigarette smoke and SARS-CoV-2 did not induce ABSC proliferation. We set out to examine the underlying mechanism governing the increased susceptibility of cigarette smoke exposed ALI to SARS-CoV-2 infection. Single cell profiling of the cultures showed that infected airway cells displayed a global reduction in gene expression across all airway cell types. Interestingly, interferon response genes were induced in SARS-CoV-2 infected airway epithelial cells in the ALI cultures but smoking exposure together with SARS-CoV-2 infection reduced the interferon response. Treatment of cigarette smoke-exposed ALI cultures with Interferon β-1 abrogated the viral infection, suggesting that the lack of interferon response in the cigarette smoke-exposed ALI cultures allows for more severe viral infection and cell death. In summary, our data show that acute smoke exposure allows for more severe proximal airway epithelial disease from SARS-CoV-2 by reducing the mucosal innate immune response and ABSC proliferation and has implications for disease spread and severity in people exposed to cigarette smoke.

SARS-CoV-2 infection of primary human lung epithelium for COVID-19 modeling and drug discovery

Coronavirus disease 2019 (COVID-19) is the latest respiratory pandemic resulting from zoonotic transmission of severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2). Severe symptoms include viral pneumonia secondary to infection and inflammation of the lower respiratory tract, in some cases causing death. We developed primary human lung epithelial infection models to understand responses of proximal and distal lung epithelium to SARS-CoV-2 infection. Differentiated air-liquid interface cultures of proximal airway epithelium and 3D organoid cultures of alveolar epithelium were readily infected by SARS-CoV-2 leading to an epithelial cell-autonomous proinflammatory response. We validated the efficacy of selected candidate COVID-19 drugs confirming that Remdesivir strongly suppressed viral infection/replication. We provide a relevant platform for studying COVID-19 pathobiology and for rapid drug screening against SARS-CoV-2 and future emergent respiratory pathogens.

ONE SENTENCE SUMMARY

A novel infection model of the adult human lung epithelium serves as a platform for COVID-19 studies and drug discovery.

SARS-CoV-2 infection of primary human lung epithelium for COVID-19 modeling and drug discovery

Coronavirus disease 2019 (COVID-19) is the latest respiratory pandemic resulting from zoonotic transmission of severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2). Severe symptoms include viral pneumonia secondary to infection and inflammation of the lower respiratory tract, in some cases causing death. We developed primary human lung epithelial infection models to understand responses of proximal and distal lung epithelium to SARS-CoV-2 infection. Differentiated air-liquid interface cultures of proximal airway epithelium and 3D organoid cultures of alveolar epithelium were readily infected by SARS-CoV-2 leading to an epithelial cell-autonomous proinflammatory response. We validated the efficacy of selected candidate COVID-19 drugs confirming that Remdesivir strongly suppressed viral infection/replication. We provide a relevant platform for studying COVID-19 pathobiology and for rapid drug screening against SARS-CoV-2 and future emergent respiratory pathogens.

One Sentence Summary

A novel infection model of the adult human lung epithelium serves as a platform for COVID-19 studies and drug discovery.

Multicenter phase 2 trial of nintedanib in advanced nonpancreatic neuroendocrine tumors

BACKGROUND

Antiangiogenic-targeting agents have low response rates in patients with nonpancreatic neuroendocrine tumors (NETs). Nintedanib is an oral antiangiogenic agent that has inhibitory effects on the fibroblast growth factor receptor, which is highly expressed in NETs. The authors hypothesized that nintedanib would be active in patients with nonpancreatic NETs.

METHODS

Patients with advanced, grade 1 or 2, nonpancreatic NETs who were receiving a stable dose of somatostatin analogue were enrolled. Nintedanib was administered at a dose of 200 mg twice daily in 28-day cycles. The primary endpoint was progression-free survival (PFS) at 16 weeks.

RESULTS

Thirty-two patients were enrolled, and 30 were evaluable for the primary outcome. Most had radiographic disease progression within 12 months before enrollment. The 16-week PFS rate was 83%, and the median PFS and overall survival were 11.0 months and 32.7 months, respectively. Nintedanib was well tolerated and delayed deterioration in quality of life. The baseline serotonin level had a strong, positive correlation with activated but exhausted T cells.

CONCLUSIONS

Nintedanib is active in nonpancreatic NETs. The immunosuppressive effect of serotonin should be targeted in future clinical trials.

A pilot study of Bruton’s tyrosine kinase inhibitor ibrutinib alone and in combination with PD-1 inhibitor nivolumab in patients with metastatic solid tumors

3111

Background: Myeloid-derived suppressor cells (MDSC) are expanded in cancer and promote immune suppression. We have shown that ibrutinib inhibits migration and immunosuppressive function of MDSC. Moreover, the combination of ibrutinib and a PD-L1 inhibitor has been found to have synergistic anti-tumor effects in a multiple solid tumor mouse models. Therefore, we conducted a pilot study testing the combination of ibrutinib and nivolumab in patients with metastatic solid tumors. Methods: Sixteen patients with advanced solid tumors were recruited to this trial. Ibrutinib was dosed as an oral single agent, starting 7 days prior to cycle 1 of nivolumab and given until cycle 1, day 8 of nivolumab. Nivolumab was administered intravenously on days 1 and 15 on 28-day cycles. Patients had blood samples collected prior to initiation of ibrutinib, day 1 of cycle 1, day 8 of cycle 1, day 1 of cycle 2, and at the time of disease progression. From these specimens, we measured circulating MDSC levels, other circulating immune subsets, T cell proliferation, and cytokines/chemokines levels. Circulating MDSC levels were measured by mass spectrometry. T cell function was evaluated by CFSE to monitor proliferating cells by dye dilution and cytokine/chemokine levels were measured with a U-PLEX assay. Data were analyzed using two-tailed, paired Student's t-tests to assess statistical significance. Results: An increase in circulating MDSC (22% to 28%; SD 9.158) levels was observed following 7 days of single-agent ibrutinib compared to baseline. However, in combination therapy, MDSC levels decreased (19%; SD 13.17) prior to cycle 2. Despite increasing levels of circulating MDSC, T cell function improved throughout the study. Furthermore, plasma levels of chemokines associated with MDSC recruitment and migration significantly decreased with ibrutinib treatment (IL-12, CCL2, CCL3, and CCL4). Of the 16 patients, four achieved a partial response and four achieved stable disease. Median progression free survival was 3.5 months and median overall survival was 11.5 months. Conclusions: The combination of ibrutinib and nivolumab was well tolerated, demonstrated early signs of immune modulation, and showed preliminary signs of promising clinical activity in patients with metastatic solid tumors. Clinical trial information: NCT03525925 .

Lenvatinib plus pembrolizumab combination therapy in patients with radioiodine-refractory (RAIR), progressive differentiated thyroid cancer (DTC): Results of a multicenter phase II international thyroid oncology group trial

6512

Background: Lenvatinib is an approved therapy for patients with RAIR DTC. While the overall response rate (ORR) is high, few patients achieve a complete response (CR) and most patients eventually have progressive disease (PD). Combination lenvatinib and pembrolizumab is being explored in many different cancers, and this combination has been approved for advanced endometrial carcinoma. Methods: Patients with RAIR DTC with Response Evaluation Criteria in Solid Tumor (RECIST v1.1) measurable PD (<14 months (mo) prior to registration) were enrolled in this single-arm multicenter phase II study. Patients were excluded if they had received previous VEGFR-directed multikinase therapy. The lenvatinib starting dose was 20 mg/day orally and pembrolizumab was 200mg IV every 3 weeks. The primary endpoint was CR. ORR, progression-free survival (PFS) and safety graded by Common Terminology Criteria for Adverse Events v4.0 were secondary endpoints. Results: Thirty patients were enrolled. The median age was 62.5 years, and 53% of the patients were women. Seventy percent of patients had grade 3 adverse events (AEs) and 10 percent had grade 4 AEs. There were no treatment-related deaths. The most common > grade 3 AEs were hypertension (47%), weight loss (13%), maculopapular rash (13%), leukopenia (7%), diarrhea (7%) and oral mucositis (7%). Twenty-one patients (70%) required lenvatinib dose reduction. Of 29 evaluable patients, 18 (62%) had a partial response (PR) and 10 (35%) had stable disease (SD). The clinical benefit rate (ORR +SD) was 97%. Median time to tumor nadir was 7.4 mo (1.6-17.8 mo). Median PFS was not yet reached. The PFS at 12 months was 74%. Median time on therapy was 9.9 mo (3.2-18.9 mo). Fourteen patients are continuing therapy (7.6-18.9 mo). Six of these patients (43%) have not yet reached tumor size nadir. Three patients (10%) had > 80% target tumor shrinkage. Conclusions: Lenvatinib plus pembrolizumab is reasonably tolerated in patients with RAIR DTC. To date, there have been no documented complete responses. Combination lenvatinib plus pembrolizumab therapy has a high ORR in patients with RAIR DTC. Continuation of this study will help determine the depth and length of the responses. Clinical trial information: NCT02973997 .

TTF-1 Positive Primary Small Cell Carcinoma of the Breast: A Case Report and Review of the Literature

Primary small cell carcinoma of the breast (SCCB) is a rare tumor subtype comprising <0.1% of all breast carcinomas. Here we present a case of thyroid transcription factor-1 (TTF-1) positive SCCB that recurred within 3 years of diagnosis in the lung and lymph nodes. Given the small number of cases, no clear guidelines exist on the appropriate management of patients with these aggressive tumors. We present a case study and review the current literature to highlight the knowledge gaps and needs of patients with these rare tumors. A 50-year-old premenopausal woman with no family history, presented with a palpable right breast mass. Biopsy was consistent with primary SCCB that was poorly differentiated, positive for synaptophysin and chromogranin and TTF-1 and presence of ductal carcinoma in situ component showing neuroendocrine differentiation. Imaging with PET, CT, and MRI brain excluded any other sites of primary disease. She underwent a right lumpectomy with axillary lymph node dissection and was treated with adjuvant cisplatin-based chemotherapy and concurrent radiation therapy. Thirty-four months later, routine scans showed a new right lower-lobe lung nodule and an enlarged sub-carinal node that was proven to be poorly differentiated neuroendocrine cancer. This case report sheds light on a rarely described disease and provides a comprehensive approach to diagnosis and management. Primary SCCB is an extremely rare, aggressive form of breast cancer that is molecularly and histologically similar to SCLC. However, a review of the literature highlights recent mutational analyses that show important differences between these two cancer types, including an increase in PIK3CA mutations in primary SCCB. Further studies, including genomic analyses are needed to better define this malignancy and to develop a standard treatment.

Transarterial Chemoembolization vs Radioembolization for Neuroendocrine Liver Metastases: A Multi-Institutional Analysis

BACKGROUND

Liver-directed hepatic arterial therapies are associated with improved survival and effective symptom control for patients with unresectable neuroendocrine liver metastases (NELM). Whether transarterial chemoembolization (TACE) or transarterial radioembolization (TARE) with yttrium-90 (y-90) are associated with improved short- or long-term outcomes is unknown.

STUDY DESIGN

A retrospective review was performed of all patients with NELM undergoing transarterial therapies, from 2000 to 2018, at 2 academic medical centers. Postoperative morbidity, radiographic response according to response evaluation criteria in solid tumors (RECIST) criteria, and long-term outcomes were compared between patients who underwent TACE vs TARE.

RESULTS

Among 248 patients with NELM, 197 (79%) received TACE and 51 (21%) received TARE. While patients who underwent TACE were more likely to have carcinoid syndrome, larger tumors, and higher chromogranin A levels, there was no difference in tumor differentiation, primary site, bilobar disease, or synchronous presentation. Nearly all TARE treatments (92%) were performed as outpatient procedures, while 99% of TACE patients spent at least 1 night in the hospital. There were no differences in overall morbidity (TARE 13.7% vs TACE 22.6%, p = 0.17), grade III/IV complication (5.9% vs 9.2%, p = 0.58), or 90-day mortality. The disease control rate (DCR) on first post-treatment imaging (RECIST partial/complete response or stable disease) was greater for TACE compared with TARE (96% vs 83%, p < 0.01). However, there was no difference in median overall survival (OS, 35.9 months vs 50.1 months, p = 0.3) or progression-free survival (PFS, 15.9 months vs 19.9 months, p = 0.37).

CONCLUSIONS

In this retrospective multi-institutional analysis, both TACE and TARE with Y-90 were safe and effective liver-directed therapies for unresectable NELM. Although TARE was associated with a shorter length of hospital stay, TACE demonstrated improved short-term DCR, and both resulted in comparable long term outcomes.

Radiographic characteristics of neuroendocrine liver metastases do not predict clinical outcomes following liver resection

Background

Previous research has demonstrated that specific radiographic criteria, including the presence of calcifications and the enhancement pattern on computed tomography (CT) imaging, correlates with clinicopathologic features and outcomes of patients with gastroenteropancreatic neuroendocrine tumors (NET). We sought to investigate whether these radiographic characteristics were prognostic among patients with neuroendocrine liver metastases (NELM) undergoing surgical resection.

Methods

The preoperative contrast-enhanced CT scans of all patients who underwent resection of NELM at a single institution between 2000-2015 were retrospectively reviewed. The presence of calcifications was determined on non-contrast phase imaging. Enhancement on the arterial phase scan was categorized as hyperenhancing, hypoenhancing, or mixed. Relevant clinicopathologic characteristics as well as recurrence-free survival (RFS) and overall survival (OS) were compared between groups.

Results

Among 82 patients who underwent resection of NELM, 57 had available data on calcifications while 51 had data available on arterial enhancement patterns. Among all patients, median age was 58 (IQR: 47-63) and the majority were female (N=48, 59.5%). The most common primary tumor locations were pancreas (N=25, 30.5%) and small bowel (N=27, 32.9%). The most commonly performed operations were right hepatectomy (N=29, 35.4%), bisegmentectomy (N=15, 18.3%), and segmentectomy (N=14, 17.1%). Median tumor number was 4 (IQR: 2-9), median Ki-67 was 5% (IQR: 2-10%), and median size of the largest liver metastasis was 4.5 (IQR: 2.8-7.7) cm. Twelve (21%) patients had tumor calcifications. Among patients with and without calcifications there were no differences in demographics, clinicopathologic characteristics, RFS (P=0.772) or OS (P=0.095). Arterial enhancement was hypoenhancing in 23 (45.1%), hyperenhancing in 10 (19.6%), and mixed in 18 (35.3%). Similarly, there were no differences between arterial enhancement groups in demographics, clinicopathologic characteristics, RFS (P=0.618) or OS (P=0.268).

Conclusions

Radiographic characteristics on contrast-enhanced CT are not associated with the outcomes of patients undergoing resection of NELM. Future investigations should evaluate the prognostic impact of functional neuroendocrine imaging.

Nivolumab in Metastatic Adrenocortical Carcinoma: Results of a Phase 2 Trial

CONTEXT

Systemic treatment of metastatic adrenocortical carcinoma (ACC) remains limited to chemotherapy and mitotane. Preliminary evidence suggesting that antitumor immune responses can be elicited in ACC has fostered interest in checkpoint inhibitors such as anti-PD-1 nivolumab.

OBJECTIVE

The primary endpoint was objective response rate according to the response evaluation criteria in solid tumors. Secondary endpoints were progression-free survival (PFS), overall survival, and safety.

DESIGN

Single-arm, multicenter, phase 2 clinical trial with two-stage design.

SETTING

Comprehensive cancer center.

PATIENTS

Ten adult patients with metastatic ACC previously treated with platinum-based chemotherapy and/or mitotane as well as patients who declined front-line chemotherapy.

INTERVENTION

Nivolumab (240 mg) IV every 2 weeks.

RESULTS

Ten patients with metastatic ACC were enrolled between March and December 2016. The median number of doses of nivolumab administered was two. Three patients only received one treatment [one died of disease progression, one discontinued due to adverse events (AEs), one withdrew after beginning treatment]. The median PFS was 1.8 months. The median follow-up was 4.5 months (range, 0.1 to 25.6 months). Two patients had stable disease for a duration of 48 and 11 weeks, respectively. One patient had an unconfirmed partial response but discontinued the study due to an AE. Most AEs were grade 1/2. The most common grade 3/4 treatment-related AEs were aspartate aminotransferase and alanine aminotransferase elevations, mucositis, and odynophagia.

CONCLUSION

Nivolumab demonstrated modest antitumor activity in patients with advanced ACC. The nivolumab safety profile was consistent with previous clinical experience without any unexpected AEs in this population.

Targeting BRAF Mutations in High-Grade Neuroendocrine Carcinoma of the Colon

Mutations in the RAS/RAF/MEK/ERK pathway leading to constitutive activation and uncontrolled cellular growth have been identified in various human malignancies, making this pathway a target for potential therapeutics. The activating BRAF^V600E mutation is one well-characterized oncogenic mutation that has been described and targeted with clinical success in various malignancies, including melanoma and hairy cell leukemia. Although BRAF-directed treatments have yielded clinical benefit in a subset of tumor types, such as melanoma, thyroid cancer, and lung cancer, BRAF inhibition fails to confer a clinical benefit in colon cancer. Identification of patients for whom BRAF inhibition may produce clinically meaningful outcomes is imperative. The incidence of BRAF mutations in neuroendocrine carcinoma (NEC) is estimated to be 5% to 10%. A recent case series demonstrated benefit in targeting the BRAF^V600E mutation in metastatic high-grade rectal NECs. Combination BRAF and MEK inhibition is known to yield improved outcomes compared with BRAF inhibition alone in melanoma. This report presents 2 patients with high-grade colorectal NECs who had different responses to treatment with combined BRAF/MEK inhibition after experiencing disease progression through first-line platinum-based chemotherapy. One patient experienced an excellent initial response to therapy before ultimately experiencing progression, and in the other patient initially had stable disease before eventually experiencing progression. These cases highlight the complicated role BRAF mutations play in gastrointestinal NECs, and the need for further research to identify not only patients who may benefit from BRAF-directed therapies but also strategies to avoid development of resistance.

Vandetanib-induced Phototoxic Drug Eruption Treated with Polypodium Leucotomos Extract: A Case Report and Review of the Literature

Vandetanib is a tyrosine kinase inhibitor approved by the United States Food and Drug Administration for the treatment of metastatic medullary thyroid cancer. It has been linked to a variety of dermatologic reactions, including photosensitivity. We describe the case of a 55-year-old man who developed a severe, painful, erythematous, bullous eruption in sun-exposed areas one month after the initiation of vandetanib. The eruption was initially refractory to treatment with steroids and did not resolve with strict sun avoidance, but finally cleared after a few weeks of oral supplementation with Polypodium leucotomos (P. leucotomos) extract. P. leucotomos is an extract derived from a tropical fern, with antioxidant effects that mitigate ultraviolet-induced cutaneous erythema via inflammatory interference and the promotion of other cytotoxic responses. This case illustrates the potential for P. leucotomos to be used as a safe and effective photoprotective agent for refractory phototoxic reactions. Further randomized, controlled trials are needed to better understand the mechanism of action and photoprotective properties of P. leucotomos in the treatment of tyrosine kinase-induced phototoxicity and other dermatoses.

Abstract CT169: Pilot study testing the effects of BTK inhibitor ibrutinib and nivolumab on levels and function of myeloid-derived suppressor cells and other immune subsets in patients with metastatic solid tumors (NCT03525925)

Background: Myeloid-derived suppressor cells (MDSC) are a naturally occurring population of immature myeloid cells with immune suppressive function that curtail inflammatory processes. In cancer, these cells abnormally expand and migrate to tumor/lymphoid regions where they negatively impact antigen specific and innate immune effector cells. Circulating MDSC levels have also been associated with the higher tumor burden and decreased survival of patients with solid tumors. Preclinical studies performed by our group demonstrated that ibrutinib (PCI-32765), an irreversible inhibitor of Bruton’s tyrosine kinase, is capable of inhibiting MDSC generation and their immunosuppressive function (A. Stiff, CA Res, 2016). We also found that the combination of ibrutinib and a PD-L1 inhibitor worked synergistically in a mouse model of mammary carcinoma. Based on these results, targeting MDSC with ibrutinib has the potential to enhance the efficacy of immune checkpoint inhibitors such as nivolumab in patients with advanced solid tumors.

Materials and Methods: This pilot study will assess the effect of single agent ibrutinib and ibrutinib in combination with nivolumab on levels and function of circulating myeloid-derived suppressor cells in 15 patients with advanced solid tumors. Eligible patients are required to have metastatic malignancy and be eligible for treatment with nivolumab as determined by the treating physician. Study subjects will be treated with ibrutinib at 420 mg given orally once daily. Nivolumab will be given at a standard dose of 240 mg IV over 30 minutes on days 1 and 15 on 28-day cycles. Ibrutinib dosing will be started 7 (+/-2) days prior to cycle 1 of nivolumab therapy and will be given until cycle 1, day 8 of nivolumab or total of 15 days (whichever comes first). Peripheral blood will be collected just prior to initiation of ibrutinib (at day -7), prior to day 1 of cycle 1, prior to day 8 of cycle 1, prior to day 1 of cycle 2 and at the time of disease progression. The primary objective is to evaluate the effect of the ibrutinib therapy on circulating levels of myeloid-derived suppressor cells (MDSC). The safety of the study combination, effect of ibrutinib/nivolumab on immune cell subsets and the length of progression-free survival will also be assessed.

Conclusion: The study opened to accrual on August 10, 2018 and is currently enrolling the target 15 patients. To date 9 patients are on study.

Citation Format: Brooke Benner, Megan Duggan, Andrew Stiff, Bhavana Konda, Robert D. Rupert, Paul Monk, Claire Verschraegen, Hiral Shah, Anne Noonan, William E. Carson, Robert Wesolowski. Pilot study testing the effects of BTK inhibitor ibrutinib and nivolumab on levels and function of myeloid-derived suppressor cells and other immune subsets in patients with metastatic solid tumors (NCT03525925) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT169.

First real-world experience of peptide receptor radionuclide therapy (PRRT) in neuroendocrine tumors (NET) since US FDA approval

e15691

Background: PRRT using 177Lu-DOTATATE was US FDA approved in Jan 2018, and real world data in the US is lacking. Methods: We retrospectively reviewed medical records of patients who began PRRT 03/14/18 - 10/01/18 at our institution. 177Lu-DOTATATE was administered at a dose of 200mCi over 20-30 min every 8 weeks for 4 doses. Infusion of arginine-lysine 25gm/25gm in 1-liter normal saline was given over 4 hours starting 30 min prior to treatment, in addition to intravenous palonosetron 0.25mg. Results: 51 patients received at least 1 of 4 doses and 40/51 were no longer on active therapy. 28/40 received all 4 doses and 12/40 discontinued treatment after < 4 doses. 25/40 were evaluable for response per RECIST v1.1. 16/25 (64%) had GI NET, 3/25 (12%) pancreatic NET, 4/25 (16%) atypical lung carcinoid, 1/25 (4%) multifocal NET, and 1/25 (4%) had paraganglioma. 28% had grade 1, 56% grade 2, and 8% (2/25) had grade 3 (Ki 67: 25% and 40%) NET. 12/25 (48%) had received ≥2 prior systemic therapies not including somatostatin analogs, and 10/25 (40%) had ≥1 prior liver-directed therapy. Median follow-up from date of last PRRT was 61.5 days. Objective response (partial response) rate was 16% (4/25; table). 18/25 (72%) had stable disease and 3/25 (12%) had progressive disease. Most adverse events (AEs) were grade 1-2 and included fatigue, nausea, abdominal pain, and cytopenias. ≥Grade 3 AEs requiring treatment discontinuation included symptomatic gastric outlet obstruction (2/51), small bowel obstruction (1/51), ischemic enteritis (1/51), confusion/bone pains (1/51), liver failure (1/51), and severe neutropenia (1/51). All patients with ≥grade 3 AEs had a high tumor burden at baseline. Conclusions: 177Lu-DOTATATE is an effective and safe treatment in advanced NET, and our results are consistent with NETTER 1 data.[Table: see text]

The emerging role of targeted therapies for advanced well-differentiated gastroenteropancreatic neuroendocrine tumors

INTRODUCTION

Gastroenteropancreatic (GEP) neuroendocrine tumors (NETs) are unique and complex neoplasms, exhibiting a wide spectrum of diverse clinical behaviors. The contemporary management of well-differentiated GEP-NETs is marked by the availability of a wide range of targeted therapies. Areas Covered: For patients with localized or oligometastatic disease, surgical resection remains the preferred approach and is associated with excellent long-term outcomes. For patients with unresectable but isolated liver metastases, multiple liver-directed therapies, including hepatic arterial based therapies and ablative techniques, exist. For patients with metastatic and progressive disease, a number of systemic therapies exist: molecular targeted agents, peptide receptor radionuclide therapy (PRRT), and systemic chemotherapy. Furthermore, somatostatin analogs (SSA) are an important component of therapy, both effectively controlling symptoms of hormonal overproduction and contributing to slowing tumor progression. Expert Opinion: In the near future, advances in our understanding of tumor biology, genetics, immunology, nanotechnology, and radiation pharmacology should only continue to expand the availability of targeted therapies, improving the outcomes of patients with GEP-NETs. We herein review the management of advanced well-differentiated GEP-NETS with a particular emphasis on the role of targeted therapies.