Critical updates in neuroendocrine tumors: Version 9 American Joint Committee on Cancer staging system for gastroenteropancreatic neuroendocrine tumors

The American Joint Committee on Cancer (AJCC) staging system for all cancer sites, including gastroenteropancreatic neuroendocrine tumors (GEP-NETs), is meant to be dynamic, requiring periodic updates to optimize AJCC staging definitions. This entails the collaboration of experts charged with evaluating new evidence that supports changes to each staging system. GEP-NETs are the second most prevalent neoplasm of gastrointestinal origin after colorectal cancer. Since publication of the AJCC eighth edition, the World Health Organization has updated the classification and separates grade 3 GEP-NETs from poorly differentiated neuroendocrine carcinoma. In addition, because of major advancements in diagnostic and therapeutic technologies for GEP-NETs, AJCC version 9 advocates against the use of serum chromogranin A for the diagnosis and monitoring of GEP-NETs. Furthermore, AJCC version 9 recognizes the increasing role of endoscopy and endoscopic resection in the diagnosis and management of NETs, particularly in the stomach, duodenum, and colorectum. Finally, T1NXM0 has been added to stage I in these disease sites as well as in the appendix.

The effect of hormonal secretion on survival in adrenocortical carcinoma: A multi-center study

BACKGROUND

Current evidence suggests that cortisol secreting adrenocortical carcinoma has worse prognosis compared to non-secreting adrenocortical carcinoma. However, the effect of other secretory subtypes is unknown.

METHODS

This multicenter study within the American-Australian-Asian Adrenal Alliance included adults with adrenocortical carcinoma (1997-2020). We compared overall survival and disease-free survival among cortisol secreting, mixed cortisol/androgen secreting, androgen secreting, and non-secreting adrenocortical carcinoma.

RESULTS

Of the 807 patients (mean age 50), 719 included in the secretory subtype analysis: 24.5% were cortisol secreting, 13% androgen secreting, 28% mixed cortisol/androgen, 32.5% non-secreting, and 2% were mineralocorticoid secreting. Median overall survival and disease-free survival for the entire cohort were 60 and 9 months, respectively. Median overall survival was 36 months for cortisol, 30 for mixed, 60 for androgen secreting, and 115 for non-secreting adrenocortical carcinoma, P < .01. Median disease-free survival was 7 months for cortisol, 8 for mixed, 10 for androgen, and 12 for non-secreting adrenocortical carcinoma, P = .06. On multivariable analysis of age, sex, Ki67%, secretory subtype, stage, resection, and adjuvant therapy, predictors of worse overall survival were older age, higher Ki67%, stage IV, mixed secreting, R1, and no adjuvant therapy, P < .05. On subgroup analysis of R0 resection, predictors of worse overall survival included older age and higher Ki67%. Ki67% ≥40, stage III and cortisol secretion were associated with worse disease-free survival.

CONCLUSION

Mixed cortisol/androgen secreting adrenocortical carcinoma was associated with worse overall survival, while cortisol or androgen secreting alone were not. Notably, among patients after R0 resection, secretory subtype did not affect overall survival. Cortisol secreting adrenocortical carcinoma demonstrated worse disease-free survival. Ki67% remained a strong predictor of worse overall survival and disease-free survival independent of stage.

The Careers and Professional Well-Being of Women Oncologists During the COVID-19 Pandemic: Responding for Tomorrow

The COVID-19 pandemic exacerbated gender inequity in medicine, with women physicians reporting greater household responsibilities than their men counterparts and steeper barriers to career advancement. The pandemic highlighted the systemic assumptions and challenges faced by women physicians, which we anticipate is also true in our field of oncology. Prior literature suggests that women physicians were tasked with increased personal and professional responsibilities without compensation for their additional work, as well as derailments in career progression and significant burnout. Our aims are to highlight areas of opportunity to optimize the workplace experience of the oncology workforce and to invest in the professional well-being and sustainability of women oncologists as a step toward global workplace equity and future pandemic preparedness.

Grade Progression and Intrapatient Tumor Heterogeneity as Potential Contributors to Resistance in Gastroenteropancreatic Neuroendocrine Tumors

Gastroenteropancreatic neuroendocrine neoplasms (NENs) are a heterogenous group of tumors that are incurable when metastatic, regardless of grade. The aim of this article is to understand tumor heterogeneity and grade progression as possible contributors to drug resistance in gastroentropancreatic neuroendocrine tumors (GEP-NETs). Heterogeneity has been observed in the genetic, pathological, and imaging features of these tumors at baseline. Diagnostic challenges related to tumor sampling and the potential for changes in grade over time further confound our ability to optimize therapy for patients. A better understanding of NEN biology and tumor heterogeneity at baseline and over time could lead to the development of new therapeutic avenues.

Efficacy and toxicity of anti-vascular endothelial growth receptor tyrosine kinase inhibitors in patients with neuroendocrine tumours - A systematic review and meta-analysis

AIM

Although anti-vascular endothelial growth factor (VEGF) receptor tyrosine kinase inhibitors (RTKIs) have been tested in patients with neuroendocrine tumours (NETs) over the last two decades, no study to date has benchmarked efficacy and toxicity of these drugs in this patient population.

METHODS

All phase II and phase III studies of anti-VEGF RTKIs in patients with NETs, published between January 1, 2000 andJuly 31, 2021, across major trial databases, were searched in August 2021 for relevant studies. The primary objectives of the meta-analysis were to compare objective response rate (ORR) and progression-free survival (PFS) between patients with pancreatic NETs (pNETs) and extra-pancreatic NETs (epNETs), and the incidence rate ratio (IRR) of adverse events between patients receiving anti-VEGF RTKIs and control.

RESULTS

1611 patients were available for the meta-analysis; 1194 received anti-VEGF RTKIs. ORR in pNETs was 18% (95% confidence interval (CI) 13-25%), while ORR in epNETs was 8% (95% CI 5-12%); test for differences between pNETs and epNETs (x12 = 8.38, p < .01). Median PFS in pNETs was 13.9 months (95% CI 11.43-16.38 months), while median PFS in epNETs was 12.71 months (95% CI 9.37-16.05 months); test for differences between pNETs and epNETs (x12 = .35, p = .55). With regards to common grade 3/4 adverse events , patients who received anti-VEGF RTKIs were more likely to experience hypertension (IRR 3.04, 95% CI 1.63-5.65) and proteinuria (IRR 5.79, 95% CI 1.09-30.74) in comparison to those who received control.

CONCLUSIONS

Anti-VEGF RTKIs demonstrate anti-tumour effect in both pNETs and epNETs, supporting their development in both populations. These agents also appear to be safe in patients with NETs.

Integrated Genomic and Clinicopathologic Approach Distinguishes Pancreatic Grade 3 Neuroendocrine Tumor From Neuroendocrine Carcinoma and Identifies a Subset With Molecular Overlap

Distinguishing grade 3 pancreatic neuroendocrine tumor (G3 PanNET) from neuroendocrine carcinoma (PanNEC) is a known diagnostic challenge, and accurate classification is critical because clinical behavior and therapies differ. Although current recommendations suggest that immunohistochemistry for p53, Rb, ATRX, and DAXX can distinguish most cases, some cases remain difficult to classify using this approach. In this study, we reviewed 47 high-grade neoplasms originally diagnosed as pancreatic neuroendocrine neoplasms. In addition to the currently recommended stains, we performed capture-based sequencing of approximately 500 cancer genes and immunohistochemistry for p16 and trypsin or chymotrypsin. Using an integrated molecular and clinicopathologic approach, 42 (89%) of 47 cases had a clear final diagnosis of either G3 PanNET (n = 17), PanNEC (n = 17), or mixed acinar-NEC (n = 8). The 17 G3 PanNETs demonstrated frequent alterations in MEN1 (71%), DAXX (47%), ATRX (24%), TSC2 (35%), SETD2 (42%), and CDKN2A (41%). Contrary to prior reports, TP53 alterations were also common in G3 PanNETs (35%) but were always mutually exclusive with CDKN2A alterations in this group. The 17 PanNECs demonstrated frequent alterations in TP53 (88%), cell cycle genes RB1 (47%), CCNE1/CCND1 (12%), CDKN2A (29%), and in KRAS (53%) and SMAD4 (41%); TP53 was coaltered with a cell cycle gene in 76% of PanNECs. Diffuse strong p16 staining was observed in 69% of PanNECs in contrast to 0% of G3 PanNETs. The 8 acinar-NECs had recurrent alterations in ATM (25%), APC (25%), and STK11 (25%). Five cases remained difficult to classify, 3 of which exhibited overlapping molecular features with alterations in MEN1 with or without ATRX, and RB1 with or without TP53, making it unclear whether to classify as PanNET or PanNEC. Our data demonstrate that molecular profiling and immunohistochemistry for p16 greatly improve the diagnostic accuracy of high-grade pancreatic neuroendocrine neoplasms and identify a subset of rare cases with overlapping features of both PanNET and PanNEC.

Pancreatic neuroendocrine neoplasms: a 2022 update for radiologists

Pancreatic neuroendocrine neoplasms (PaNENs) are a unique group of pancreatic neoplasms with a wide range of clinical presentations and behaviors. Given their heterogeneous appearance and increasing detection on cross-sectional imaging, it is essential that radiologists understand the variable presentation and distinctions PaNENs display compared to other pancreatic neoplasms. Additionally, some of these neoplasms may be hormonally functional, and it is imperative that radiologists be aware of the common clinical presentations of hormonally active PaNENs. Knowledge of PaNEN pathology and treatments may influence which imaging modality is optimal for each patient. Each imaging modality used for PaNENs has distinct advantages and disadvantages, particularly in different treatment settings. Thus, the focus of this manuscript is to provide an update for the radiologist on PaNEN pathology, imaging, and treatments.

DLL3 as an Emerging Target for the Treatment of Neuroendocrine Neoplasms

INTRODUCTION

Neuroendocrine neoplasms (NEN) are heterogeneous malignancies that can arise at almost any anatomical site and are classified as biologically distinct well-differentiated neuroendocrine tumors (NET) and poorly differentiated neuroendocrine carcinomas (NEC). Current systemic therapies for advanced disease, including targeted therapies, chemotherapy, and immunotherapy, are associated with limited duration of response. New therapeutic targets are needed. One promising target is delta-like ligand 3 (DLL3), an inhibitory ligand of the Notch receptor whose overexpression on the surface of NEN is associated with tumorigenesis.

METHODS

This article is a narrative review that highlights the role of DLL3 in NEN progression and prognosis, the potential for therapeutic targeting of DLL3, and ongoing studies of DLL3-targeting therapies. Classification, incidence, pathogenesis, and current management of NEN are reviewed to provide biological context and illustrate the unmet clinical needs.

DISCUSSION

DLL3 is overexpressed in many NENs, implicated in tumor progression, and is typically associated with poor clinical outcomes, particularly in patients with NEC. Targeted therapies using DLL3 as a homing beacon for cytotoxic activity mediated via several different mechanisms (eg, antibody-drug conjugates, T-cell engager molecules, CAR-Ts) have shown promising clinical activity in small-cell lung cancer (SCLC). DLL3 may be a clinically actionable target across NEN.

CONCLUSIONS

Current treatment options for NEN do not provide sustained responses. DLL3 is expressed on the cell surface of many NEN types and is associated with poor clinical outcomes. Initial clinical studies targeting DLL3 therapeutically in SCLC have been promising, and additional studies are expanding this approach to the broader group of NEN.

Long-Term Treatment with Telotristat Ethyl in Patients with Carcinoid Syndrome Symptoms: Results from the TELEPATH Study

INTRODUCTION

Telotristat ethyl is indicated for use in combination with somatostatin analogs (SSAs) to treat carcinoid syndrome (CS) diarrhea uncontrolled by SSAs alone in adults, but long-term safety and efficacy data beyond 48 weeks are needed.

OBJECTIVES

The aims of the study were to evaluate the long-term safety and tolerability of telotristat ethyl and its effect on quality of life (QOL) in patients with CS.

METHODS

In this phase 3, nonrandomized, multicenter, open-label, long-term extension study (TELEPATH), patients who participated in phase 2 or 3 trials of telotristat ethyl continued treatment at their present dose level (250 or 500 mg thrice daily) for 84 weeks. Safety and tolerability, the primary endpoint, were assessed by monitoring adverse events (AEs), serious AEs, AEs of special interest (AESIs; including liver-related AEs, depression, and gastrointestinal AEs), and deaths. The secondary objective was to evaluate changes in patients' QOL using validated cancer questionnaires and a subjective global assessment of CS symptoms.

RESULTS

In 124 patients exposed to telotristat ethyl for a mean of 102.6 ± 53.2 weeks, the type and frequency of AEs were consistent with those reported in previous trials. The occurrence of AESIs was not related to dosage or duration of therapy. Most AEs were mild to moderate in severity, and no deaths were related to telotristat ethyl. QOL scores remained stable, and the majority of patients reported adequate symptom relief throughout the study.

CONCLUSIONS

Safety results of TELEPATH support the long-term use of telotristat ethyl in patients with CS diarrhea. Telotristat ethyl was well-tolerated and associated with sustained improvement in QOL scores (NCT02026063).

Adjuvant Therapy for Stage II Colon Cancer: ASCO Guideline Update

PURPOSE

To develop recommendations for adjuvant therapy for patients with resected stage II colon cancer.

METHODS

ASCO convened an Expert Panel to conduct a systematic review of relevant studies and develop recommendations for clinical practice.

RESULTS

Twenty-one observational studies and six randomized controlled trials met the systematic review inclusion criteria.

RECOMMENDATIONS

Adjuvant chemotherapy (ACT) is not routinely recommended for patients with stage II colon cancer who are not in a high-risk subgroup. Patients with T4 tumors are at higher risk of recurrence and should be offered ACT, whereas patients with other high-risk factors, including sampling of fewer than 12 lymph nodes in the surgical specimen, perineural or lymphatic invasion, poorly or undifferentiated tumor grade, intestinal obstruction, tumor perforation, or grade BD3 tumor budding, may be offered ACT. The addition of oxaliplatin to fluoropyrimidine-based ACT is not routinely recommended, but may be offered as a result of shared decision making. Patients with mismatch repair deficiency/microsatellite instability tumors should not be routinely offered ACT; if the combination of mismatch repair deficiency/microsatellite instability and high-risk factors results in a decision to offer ACT, oxaliplatin-containing chemotherapy is recommended. Duration of oxaliplatin-containing chemotherapy is also addressed, with recommendations for 3 or 6 months of treatment with capecitabine and oxaliplatin or fluorouracil, leucovorin, and oxaliplatin, with decision making informed by key evidence of 5-year disease-free survival in each treatment subgroup and the rate of adverse events, including peripheral neuropathy.Additional information is available at www.asco.org/gastrointestinal-cancer-guidelines.

Neuroendocrine and Adrenal Tumors, Version 2.2021, NCCN Clinical Practice Guidelines in Oncology

The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Neuroendocrine and Adrenal Gland Tumors focus on the diagnosis, treatment, and management of patients with neuroendocrine tumors (NETs), adrenal tumors, pheochromocytomas, paragangliomas, and multiple endocrine neoplasia. NETs are generally subclassified by site of origin, stage, and histologic characteristics. Appropriate diagnosis and treatment of NETs often involves collaboration between specialists in multiple disciplines, using specific biochemical, radiologic, and surgical methods. Specialists include pathologists, endocrinologists, radiologists (including nuclear medicine specialists), and medical, radiation, and surgical oncologists. These guidelines discuss the diagnosis and management of both sporadic and hereditary neuroendocrine and adrenal tumors and are intended to assist with clinical decision-making. This article is focused on the 2021 NCCN Guidelines principles of genetic risk assessment and counseling and recommendations for well-differentiated grade 3 NETs, poorly differentiated neuroendocrine carcinomas, adrenal tumors, pheochromocytomas, and paragangliomas.

Spartalizumab in metastatic, well/poorly-differentiated neuroendocrine neoplasms

Spartalizumab, a humanized anti-programmed death protein 1 (PD-1) monoclonal antibody, was evaluated in patients with well-differentiated metastatic grade 1/2 neuroendocrine tumors (NET) and poorly-differentiated gastroenteropancreatic neuroendocrine carcinomas (GEP-NEC). In this phase II, multicenter, single-arm study, patients received spartalizumab 400 mg every 4 weeks until confirmed disease progression or unacceptable toxicity. The primary endpoint was confirmed overall response rate (ORR) according to blinded independent review committee using response evaluation criteria in solid tumors 1.1. The study enrolled 95 patients in the NET group (30, 32 and 33 in the thoracic, gastrointestinal, and pancreatic cohorts, respectively), and 21 patients in the GEP-NEC group. The ORR was 7.4% (95% confidence interval [CI]: 3.0, 14.6) in the NET group (thoracic, 16.7%; gastrointestinal, 3.1%; pancreatic, 3.0%), which was below the predefined success criterion of ≥10%, and 4.8% (95% CI: 0.1, 23.8) in the GEP-NEC group. In the NET and GEP-NEC groups, the 12-month progression-free survival was 19.5% and 0%, respectively, and the 12-month overall survival was 73.5% and 19.1%, respectively. The ORR was higher in patients with ≥1% PD-L1 expression in immune/tumor cells or ≥1% CD8+ cells at baseline. The most common adverse events considered as spartalizumab-related included fatigue (29.5%) and nausea (10.5%) in the NET group, and increased aspartate and alanine aminotransferases (each 14.3%) in the GEP-NEC group. The efficacy of spartalizumab was limited in this heterogeneous and heavily pre-treated population; however, the results in the thoracic cohort is encouraging and warrants further investigation. Adverse events were manageable and consistent with previous experience.

Abstract A108: Differences in incidence by sex and race/ethnicity of adrenocortical carcinomas and malignant pheochromocytomas and paragangliomas in California

Background: Malignant pheochromocytomas (PHEO), paragangliomas (PGL), and adrenocortical carcinomas (ACC) are rare endocrine malignancies with limited data regarding risk factors. To further elucidate their epidemiology, we sought to characterize the burden of malignant PHEO, PGL, and ACC in California. Methods: Using the population-based California Cancer Registry, we identified all new diagnoses of malignant PHEO, PGL, and ACC in California from 1992-2016 (ICD-O-3 codes 8700/3, 8680/3, and 8393/3). We calculated age-adjusted incidence rates (AIR) standardized to the 2000 United States census. We compared AIRs by sex, race/ethnicity (non-Hispanic White, non-Hispanic Black, Hispanic, and Asian/Pacific Islander), and county of residence (categorized as urban versus suburban/rural) using SEER*Stat and generated IR ratios (IRR). Results: Between 1992-2016, there were 261 incident cases of malignant PHEO, 271 of malignant PGL, and 866 of ACC in California. Overall AIR per 100,000 person-years were 0.03 for PHEO, 0.03 for PGL, and 0.10 for ACC. Incidence differed by both sex and race/ethnicity. Men had a higher incidence of PGL than women (IRR 1.49, 95% confidence interval [CI] 1.13-1.98; p&lt;0.05) and tended towards higher incidence of PHEO (IRR 1.24, 95% CI 0.97-1.60; p=0.09), while men had a lower incidence of ACC than women (IRR 0.80, 95% CI 0.69-0.92; p&lt;0.05). Compared with non-Hispanic White Californians, non-Hispanic Black Californians had higher PHEO incidence (IRR 1.65, 95% CI 1.05-2.51; p&lt;0.05), whereas PGL incidence was lower for Hispanic (IRR 0.60, 95% CI 0.41-0.87; p&lt;0.05) and Asian/Pacific Islander Californians (IRR 0.60, 95% CI 0.35-0.97; p&lt;0.05). Compared with non-Hispanic White Californians, ACC incidence was lower in non-Hispanic Black (IRR 0.58, 95% CI 0.40-0.82; p&lt;0.05), Hispanic (IRR 0.65, 95% CI 0.54-0.78; p&lt;0.05), and Asian/Pacific Islander Californians (IRR 0.60, 95% CI 0.46-0.76; p&lt;0.05). There were no differences in IRRs according to county of residence for either PHEO, PGL, or ACC. Conclusions: Malignant PHEO, PGL, and ACC remain rare cancers in California, with disease-specific differences in IRR’s by sex and race/ethnicity but not by urban versus suburban/rural county of residence. We report novel findings of a higher incidence of malignant PHEO in non-Hispanic Black Californians and a lower incidence of malignant PGL in Hispanic and Asian/Pacific Islander Californians. We also confirm higher incidence of ACC in women and non-Hispanic White Californians. Additional research is needed to clarify whether these differences reflect disparities in access to care.

Citation Format: Claire K. Mulvey, Alan Paciorek, Brandon Shih, Meg McKinley, Dawn Pearson, Iona Cheng, Li Zhang, Ann Griffin, Quan-Yang Duh, Sanziana Roman, Julie Ann Sosa, Insoo Suh, Chienying Liu, Katherine Van Loon, Emily Bergsland. Differences in incidence by sex and race/ethnicity of adrenocortical carcinomas and malignant pheochromocytomas and paragangliomas in California [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr A108.

Abstract D111: Incidence and survival patterns of gastroenteropancreatic neuroendocrine neoplasms in California

Background. Neuroendocrine neoplasms (NEN) are a heterogeneous group of rare tumors. There is a paucity of epidemiologic data regarding risk factors. We aimed to characterize the burden of NEN in California with its diverse racial/ethnic populations. Methods Using California Cancer Registry, we identified all newly diagnosed NEN from gastroenteropancreatic (GEP) sites 1992-2015. Annual age-adjusted incidence rates (AIR) per 100,000 person-years were compared, and average annual percent change (APC) in rates were compared according to sex, race-ethnicity (non-Hispanic (NH) white, NH black, Asian/Pacific Islander, American Indian, Hispanic), primary tumor site (stomach, small intestine, colon or rectum, appendix, pancreas), stage, and type of county of residence (urban, suburban, rural) using incidence rate ratios (IRR). Overall survival from diagnosis to death by any cause was estimated by Kaplan-Meier method and compared using log-rank tests. Results There were 23,983 GEP NEN incident cases and 9,910 deaths 1992-2015. All AIRs increased over the 24 years, with the greatest increase in Hispanics with pancreatic NEN (APC 8.9). Rates for the period 2011-2015 varied according to primary tumor site: colorectal (AIR 1.41); small intestinal (AIR 0.97); pancreatic (AIR 0.92); stomach (AIR 0.44); and appendiceal (AIR 0.36). Comparing rates by populations the greatest disparities were for NH blacks vs. Asians with small intestinal NEN (IRR 7.01 95% confidence interval (CI) [5.37-9.21]) or appendiceal NEN (IRR 3.74 95% CI [2.34-6.08]), for NH whites vs. Asians with small intestinal NEN (IRR 4.34 95% CI [3.44-5.53]) or appendiceal NEN (IRR 5.10 95% CI [3.54-7.59]), for NH blacks vs. NH whites with colorectal NEN (IRR 2.59 95% CI [2.27-2.94]), and for NH whites vs. Hispanics with appendiceal NEN (IRR 2.54 95% CI [2.08-3.12]). Statistically significantly longer survival estimates were observed in women (median 13.1 years) vs. men (11.6 years), and in Asians/Pacific Islanders (20.7 years) and Hispanics (16.7 years) vs. NH blacks (12.3 years) and NH whites (9.6 years). No significant survival differences were detected across county types. Survival estimates were significantly different across primary tumor sites: colorectal (median 19.9 years); appendiceal (16.0 years); small intestinal (10.1 years); stomach (9.7 years); and pancreatic (4.4 years). Conclusions Incidence rates of GEP NEN in California steadily increase from 1992 through 2015 for all populations. Recent AIRs for particular race-ethnicities and primary tumor sites are more than double others, exposing large disparities. Survival estimates differ significantly by primary tumor site, sex, race-ethnicity, and stage, but not by county. These findings show some higher incidence rates and longer survival than in previously published estimates nationwide and add information about GEP NEN in Hispanic and Asian/Pacific Islander populations in California. Additional research is needed to clarify reasons for the disparities.

Citation Format: Alan Paciorek, Brandon Shih, Meg McKinley, Iona Cheng, Li Zhang, Claire Mulvey, Ann Griffin, Eric Nakakura, Quan-Yang Duh, Insoo Suh, Katherine Van Loon, Emily Bergsland. Incidence and survival patterns of gastroenteropancreatic neuroendocrine neoplasms in California [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr D111.

Pembrolizumab for the treatment of programmed death-ligand 1-positive advanced carcinoid or pancreatic neuroendocrine tumors: Results from the KEYNOTE-028 study

BACKGROUND

Despite a protracted disease course and multiple available therapies, patients with well-differentiated neuroendocrine tumors (NETs) inevitably experience disease progression. Programmed death-ligand 1 (PD-L1) has been associated with NET progression and prognosis. The multicohort, phase 1 KEYNOTE-028 study (ClinicalTrials.gov identifier NCT02054806) evaluated the activity and safety of the anti-programmed cell death protein 1 immunotherapy pembrolizumab in patients with well-differentiated or moderately-differentiated NETs.

METHODS

Patients with PD-L1-positive, locally advanced or metastatic carcinoid or well-differentiated or moderately-differentiated pancreatic NETs (pNETs) were enrolled into separate cohorts and received pembrolizumab at a dose of 10 mg/kg every 2 weeks for up to 2 years. The objective response rate was the primary endpoint (as per Response Evaluation Criteria in Solid Tumors version 1.1, by investigator review). Safety was a secondary endpoint.

RESULTS

Of 170 and 106 patients, respectively, who had evaluable samples among those screened for the carcinoid and pNET cohorts, 21% and 25%, respectively, had PD-L1-positive tumors; of these, 25 and 16 patients, respectively, were eligible and treated. The median follow-up was 20 months (range, 2-35 months) and 21 months (range, 5-32 months), respectively. The objective response rate was 12.0% (95% CI, 2.5%-31.2%) and 6.3% (95% CI, 0.2%-30.2%), respectively; 3 partial responses occurred among the carcinoid cohort and 1 among the pNET cohort. The median duration of response in the carcinoid cohort was 9.2 months (range, 6.9-11.1 months), and was not reached in the pNET cohort. No complete responses occurred. Treatment-related adverse events occurred in 68% and 69% of patients, respectively, most often diarrhea (7 patients in the carcinoid cohort and 4 patients in the pNET cohort) and fatigue (6 patients in each cohort). Hypothyroidism was the most common immune-mediated adverse event (5 patients in the carcinoid cohort and 2 patients in the pNET cohort).

CONCLUSIONS

Pembrolizumab demonstrated antitumor activity in a subset of patients with NETs and was well-tolerated.

Efficacy and Safety of Pembrolizumab in Previously Treated Advanced Neuroendocrine Tumors: Results From the Phase II KEYNOTE-158 Study

PURPOSE

KEYNOTE-158 (ClinicalTrials.gov identifier: NCT02628067) investigated the efficacy and safety of pembrolizumab across multiple cancers. We present results from patients with previously treated advanced well-differentiated neuroendocrine tumors (NET).

PATIENTS AND METHODS

Pembrolizumab 200 mg was administered every 3 weeks for 2 years or until progression, intolerable toxicity, or physician/patient decision. Tumor imaging was performed every 9 weeks for the first year and then every 12 weeks. Endpoints included objective response rate (ORR) per RECIST v1.1 by independent central radiologic review (primary) and duration of response (DOR), progression-free survival (PFS), overall survival (OS), and safety (secondary).

RESULTS

A total of 107 patients with NETs of the lung, appendix, small intestine, colon, rectum, or pancreas were treated. Median age was 59.0 years (range, 29-80), 44.9% had ECOG performance status 1, 40.2% had received ≥3 prior therapies for advanced disease, and 15.9% had PD-L1-positive tumors (combined positive score ≥1). Median follow-up was 24.2 months (range, 0.6-33.4). ORR was 3.7% (95% CI, 1.0-9.3), with zero complete responses and four partial responses (three pancreatic and one rectal) all in patients with PD-L1-negative tumors. Median DOR was not reached, with one of four responses ongoing after ≥21 months follow-up. Median PFS was 4.1 months (95% CI, 3.5-5.4); the 6-month PFS rate was 39.3%. Median OS was 24.2 months (95% CI, 15.8-32.5). Treatment-related adverse events (AE) occurred in 75.7% of patients, 21.5% of whom had grade 3-5 AEs.

CONCLUSIONS

Pembrolizumab monotherapy showed limited antitumor activity and manageable safety in patients with previously treated advanced well-differentiated NETs.

Evaluation of meaningful change in bowel movement frequency for patients with carcinoid syndrome

Background

Carcinoid syndrome is associated with a reduced quality of life that can be attributed to symptoms such as diarrhea and fatigue as well as social and financial issues. This study was conducted to psychometrically assess meaningful change in bowel movement frequency among carcinoid syndrome patients using data from the TELESTAR clinical study.

Methods

An anchor-based approach for deriving meaningful change thresholds consisted of mapping change from baseline bowel movement frequency to other patient-reported assessments of change. These included the European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire - Core Questionnaire (QLQ-C30) Diarrhea Symptom responders, the EORTC Gastrointestinal NET questionnaire (GI.NET21) GI Symptom responders, and reported adequate relief at Week 12 (≥ 10-point score decrease from Day 1 to Week 12). Parameters included within-group mean change from baseline to Week 12, t-tests of the change (Wilcoxon rank sum for adequate relief), and effect size.

Results

There were 135 carcinoid syndrome patients with a mean baseline frequency of 5.7 bowel movements a day. A distribution-based method yielded meaningful change estimates of 0.62 bowel movements a day for overall frequency and 0.83 bowel movements a day at Week 12. Anchor-based analysis indicated a large effect size among patients who reported adequate relief at Week 12 (− 1.58; n = 18; P = 0.014), the QLQ-C30 Diarrhea domain responders (− 1.24; n = 40; P < 0.001), and the GI.NET21 GI Symptoms Domain responders (− 1.49; n = 25; P = 0.005). Exit interview data for meaningful change yielded effect size estimates of − 1.57 for overall change during the Double-blind Treatment Period and − 1.97 for change between Baseline and Week 12.

Conclusions

Meaningful change derivation is critical to interpret patient outcomes for evaluating treatment efficacy. In this study, carcinoid syndrome patients experienced clinically meaningful reductions in bowel movement frequency of ≥30% over 12 weeks with telotristat ethyl treatment.

Trial registration

NCT01677910.

NCCN Guidelines Insights: Neuroendocrine and Adrenal Tumors, Version 2.2018

The NCCN Guidelines for Neuroendocrine and Adrenal Tumors provide recommendations for the management of adult patients with neuroendocrine tumors (NETs), adrenal gland tumors, pheochromocytomas, and paragangliomas. Management of NETs relies heavily on the site of the primary NET. These NCCN Guidelines Insights summarize the management options and the 2018 updates to the guidelines for locoregional advanced disease, and/or distant metastasis originating from gastrointestinal tract, bronchopulmonary, and thymus primary NETs.

Follow-up Recommendations for Completely Resected Gastroenteropancreatic Neuroendocrine Tumors

There is no consensus on optimal follow-up for completely resected gastroenteropancreatic neuroendocrine tumors. Published guidelines for follow-up are complex and emphasize closer surveillance in the first 3 years after resection. Neuroendocrine tumors have a different pattern and timescale of recurrence, and thus require more practical and tailored follow-up. The Commonwealth Neuroendocrine Tumour Collaboration convened an international multidisciplinary expert panel, in collaboration with the North American Neuroendocrine Tumor Society, to create patient-centered follow-up recommendations for completely resected gastroenteropancreatic neuroendocrine tumors. This panel used the RAND/UCLA (University of California, Los Angeles) Appropriateness Method to generate recommendations. A large international survey was conducted outlining current the surveillance practice of neuroendocrine tumor practitioners and shortcomings of the current guidelines. A systematic review of available data to date was supplemented by recurrence data from 2 large patient series. The resultant guidelines suggest follow-up for at least 10 years for fully resected small-bowel and pancreatic neuroendocrine tumors and also identify clinical situations in which no follow-up is required. These recommendations stratify follow-up strategies based on evidence-based prognostic factors that allow for a more individualized patient-centered approach to this complex and heterogeneous malignant neoplasm.

Long-Term Safety Experience with Telotristat Ethyl Across Five Clinical Studies in Patients with Carcinoid Syndrome

BACKGROUND

Patients with neuroendocrine tumors (NETs) and carcinoid syndrome experience considerable morbidity and mortality; carcinoid syndrome may be associated with shorter survival. Carcinoid syndrome is linked to tumoral secretion of serotonin and other bioactive substances. The subsequent debilitating diarrhea and urgency to defecate pose significant health risks. In previous studies, telotristat ethyl, a tryptophan hydroxylase inhibitor, was effective and well tolerated in treating carcinoid syndrome diarrhea. We present pooled safety data from five clinical trials with telotristat ethyl in patients with carcinoid syndrome.

SUBJECTS, MATERIALS, AND METHODS

Adverse events reported during telotristat ethyl treatment were pooled from two phase II and three phase III clinical trials in 239 patients with carcinoid syndrome. Long-term safety of telotristat ethyl and causes of hospitalization and death were reviewed; overall survival was estimated.

RESULTS

Mean (median; range) duration of exposure and follow-up was 1.3 years (1.1 years; 1 week to 5.7 years), with 309 total patient-years of exposure. Leading causes of hospitalization were gastrointestinal disorders or were related to the underlying tumor and related treatment. Survival estimates at 1, 2, and 3 years were 93%, 88%, and 77%. Nearly all deaths were due to progression or complication of the underlying disease; none were attributable to telotristat ethyl. There was one death in year 4.

CONCLUSION

Based on long-term safety data, telotristat ethyl is well tolerated and has a favorable long-term safety profile in patients with carcinoid syndrome.

IMPLICATIONS FOR PRACTICE

Carcinoid syndrome can cause persistent diarrhea, even in patients treated with somatostatin analogs. Across five clinical trials in patients with carcinoid syndrome, telotristat ethyl has been well tolerated and efficacious, providing clinicians with a new approach to help control carcinoid syndrome diarrhea, in addition to somatostatin analog therapy. By reducing the stool frequency in patients with carcinoid syndrome whose diarrhea is refractory to anticholinergics, such as loperamide and atropine/diphenoxylate, and somatostatin analog dose escalation, improvement in quality of life becomes an achievable goal.

Duration of Oxaliplatin-Containing Adjuvant Therapy for Stage III Colon Cancer: ASCO Clinical Practice Guideline

PURPOSE

To develop recommendations for duration of adjuvant chemotherapy with a fluoropyrimidine and oxaliplatin for patients with completely resected stage III colon cancer based on the results of trials of 3 months compared with 6 months of treatment.

METHODS

ASCO convened an Expert Panel and conducted a systematic review of relevant studies. The guideline recommendations were based on the review of evidence by the Expert Panel.

RESULTS

Pooled data from the six International Duration Evaluation of Adjuvant Chemotherapy (IDEA) Collaboration randomized controlled trials comprise the evidence base for these guideline recommendations.

RECOMMENDATIONS

The recommendations for therapy duration apply to patients with completely resected stage III colon cancer who are being offered adjuvant chemotherapy with oxaliplatin and a fluoropyrimidine. Recommendations are informed by the findings of a recent pooled analysis of clinical trials that compared 6 months versus 3 months of oxaliplatin-based chemotherapy. For patients at a high risk of recurrence (T4 and/or N2), adjuvant chemotherapy should be offered for a duration of 6 months. For patients at a low risk of recurrence (T1, T2, or T3 and N1), either 6 months of adjuvant chemotherapy or a shorter duration of 3 months may be offered on the basis of a potential reduction in adverse events and no significant difference in disease-free survival with the 3-month regimen. In determining duration of therapy, the Expert Panel recommends a shared decision-making approach, taking into account patient characteristics, values and preferences, and other factors and including a discussion of the potential for benefit and risks of harm associated with treatment duration. Additional information is available at www.asco.org/gastrointestinal-cancer-guidelines .

Identification of high-risk human papillomavirus and Rb/E2F pathway genomic alterations in mutually exclusive subsets of colorectal neuroendocrine carcinoma

Colorectal neuroendocrine carcinomas, both small cell and large cell types, are highly aggressive tumors with poor prognosis compared with colorectal adenocarcinoma. The molecular drivers of neuroendocrine carcinoma are best defined in small cell lung cancer, which shows near-universal genomic alterations in TP53 and RB1. The genetics of colorectal neuroendocrine carcinoma remain poorly understood; recent studies demonstrated infrequent RB1 alterations and genetics closely resembling colorectal adenocarcinoma. To better define the molecular pathogenesis of colorectal neuroendocrine carcinoma, we performed capture-based next-generation sequencing on 25 cases and evaluated for expression of p53, Rb, p16, and high-risk human papillomavirus (HR-HPV) subtypes using immunohistochemistry, in situ hybridization, and polymerase chain reaction. Rb/E2F pathway dysregulation was identified in nearly all cases (23/25, 92%) and occurred via three distinct mechanisms. First, RB1 genomic alteration was present in 56% (14/25) of cases and was accompanied by Rb protein loss, high p16 expression, and absence of HR-HPV; these cases also had frequent genomic alterations in TP53, the PI3K/Ras and Wnt pathways, as well as in DNA repair genes, with 4/14 cases being hypermutated. Second, 16% (4/25) of cases, all left-sided, had TP53 alteration without RB1 alteration; half of these harbored high-level amplifications in CCNE1 and MYC or MYCN and arose in patients with ulcerative colitis. Finally, 28% (7/25) of cases, all rectal or anal, lacked genomic alterations in RB1 or TP53 but were positive for HR-HPV. Our data demonstrate that Rb/E2F pathway dysregulation is essential in the pathogenesis of colorectal neuroendocrine carcinoma, akin to neuroendocrine carcinomas in other anatomic sites. Moreover, colorectal neuroendocrine carcinomas stratify into three distinct molecular subgroups, which can be differentiated based on Rb protein and HR-HPV status. HR-HPV infection represents a distinct mechanism for Rb and p53 inactivation in cases lacking genomic alterations in either gene. Differential treatment strategies for hypermutated and HPV-driven cases could improve patient outcomes.

Emerging value of multigene panels for germline testing in patients with neuroendocrine tumors

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Background: Neuroendocrine tumors (NETs) are known to be associated with hereditary syndromes stemming from MEN1, VHL, SDH or TSC mutations. Recent data suggest that additional germline mutations may be relevant, implying a role of germline testing with multigene panels. We examined genetic counseling (GC) referral and testing patterns, test results, and their changes over time in NET patients (pts). Methods: Retrospective chart review was conducted in 236 NET pts referred to UCSF Cancer Genetics and Prevention Program 2004-2017. Univariate logistic models were used to assess relationship between binary outcome and covariate. STATA was used for analysis and statistical significance was based on p < 0.05. Results: 139 referred pts (59%) followed up with GC. Pts with >1 family members diagnosed with cancer were more likely to attend GC [OR=2.75, p=0.010]. Among 107 pts tested, small bowel NETs were less associated with testing than pancreatic NETs [OR=0.15, p=0.001]. Single-gene tests were routine until 2015, when panels up to 130 genes became standard. Overall, 31 pts (29% of 107 tested) had a pathogenic/likely pathogenic (P/LP) result. There was no significant difference between single and multi-gene tests in identifying P/LP mutations (likely due to changes in threshold for testing over time), but greater diversity in P/LP mutations was noted with larger panels. Functional tumors showed lower rate of P/LP mutations than non-functional [OR=0.17, p=0.037]. Conclusions: Only 59% of referred pts followed up with GC, suggesting significant barriers to testing exist. Of those tested, 29% harbored a P/LP mutation. Germline mutations not traditionally associated with NETs were identified, highlighting the potential importance of larger panels to detect rare mutations. [Table: see text]

Understanding the Patient Experience with Carcinoid Syndrome: Exit Interviews from a Randomized, Placebo-controlled Study of Telotristat Ethyl

PURPOSE

Telotristat ethyl, an oral tryptophan hydroxylase inhibitor, is intended to treat carcinoid syndrome by reducing serotonin production. Telotristat ethyl was evaluated in TELESTAR, a Phase III study for patients who had carcinoid syndrome with at least 4 bowel movements (BMs) per day and who were receiving somatostatin analogue therapy. This interview substudy was conducted to provide insight into the patient experience in TELESTAR and to help understand whether reductions in BM frequency (the primary end point) and other symptoms were clinically meaningful.

METHODS

Participating sites were asked to invite (before randomization) all eligible patients to telephone interviews scheduled at the end of the double-blind treatment period. Patients and interviewers were blinded to treatment.

FINDINGS

All 35 interviewed participants reported diarrhea and/or excessive BMs at baseline. Patients reported that these symptoms negatively affected emotional, social, physical, and occupational well-being. Prespecified criteria for treatment response (achieving ≥30% reduction in BM frequency for at least 50% of the days) were met by 8 of 26 patients taking telotristat ethyl and 1 of 9 patients taking placebo. All 8 patients taking telotristat ethyl described clinically meaningful reductions in BM frequency and were very satisfied with the ability of the study drug to control their carcinoid syndrome symptoms. Overall, reports of being very satisfied were observed in 12 patients taking telotristat ethyl and 0 taking placebo.

IMPLICATIONS

Patient interviews revealed that TELESTAR patients, at baseline, were significantly affected by their high BM frequency. Patient reports of their clinical trial experience supported the significance of the primary end point and clinical responder analysis in TELESTAR, helping identify and understand clinically meaningful change produced by telotristat ethyl.

Evaluation of meaningful change in bowel movement frequency for patients with carcinoid syndrome

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Background: Telotristat ethyl is a tryptophan hydroxylase inhibitor in development for the treatment of carcinoid syndrome (CS) in patients who receive somatostatin analog (SSA) therapy. In TELESTAR, a pivotal Phase 3 study, telotristat ethyl significantly reduced bowel movement (BM) frequency compared to placebo. The objective of this study was to psychometrically assess meaningful change in BM frequency using data collected within the TELESTAR study. Methods: An anchor-based approach consisted of mapping change from baseline in BM frequency to other patient reported assessments of change. These included the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire - Core Questionnaire (EORTC QLQ-C30) Diarrhea Symptom responders, the EORTC GI.NET21 GI Symptom responders, and patient reported adequate relief at Week 12 (responders had a ≥ 10-point decrease in scores from Day 1 to Week 12). Parameters included within group mean change from baseline to Week 12, t-tests of the change (Wilcoxon Rank Sum for adequate relief), effect size (ES: calculated as the difference between mean on-treatment and baseline BM frequency, divided by the standard deviation of the baseline), and related confidence intervals. Results: There were 135 patients with CS, with a mean age of 63.6 years and mean baseline BM frequency of 5.7 BM/day. Anchor-based analyses indicated significant differences in BM frequency between adequate relief groups at Week 12 (ES: −1.58 vs. −0.79; p = 0.014), responders and non-responders on the EORTC QLQ-C30 Diarrhea Symptoms domain (ES: −1.24 vs. −0.59; p < 0.0001), and responders and non-responders on the EORTC GI.NET21 GI Symptoms Domain (ES: −1.49 vs. −0.75; p = 0.0053). These corresponded to BM frequency reductions of 1.7–1.9 BM/day, or ≥ 30%. Conclusions: Results of this study indicated that patients with CS experienced clinically meaningful reductions in BM frequency of ≥ 30% over the course of 12 weeks. Clinical trial information: NCT01677910.

Evaluation of meaningful change in bowel move frequency for patients with carcinoid syndrome

583

Background: Telotristat ethyl is a tryptophan hydroxylase inhibitor in development for the treatment of carcinoid syndrome (CS) in patients who receive somatostatin analog (SSA) therapy. In TELESTAR, a pivotal Phase 3 study, telotristat ethyl significantly reduced bowel movement (BM) frequency compared to placebo. Objective: The objective of this study was to psychometrically assess meaningful change in BM frequency using data collected within the TELESTAR study. Methods: An anchor-based approach consisted of mapping change from baseline in BM frequency to other patient reported assessments of change. These included the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire - Core Questionnaire (EORTC QLQ-C30) Diarrhea Symptom responders, the EORTC GI.NET21 GI Symptom responders, and patient reported adequate relief at Week 12 (responders had a ≥ 10-point decrease in scores from Day 1 to Week 12). Parameters included within group mean change from baseline to Week 12, t-tests of the change (Wilcoxon Rank Sum for adequate relief), effect size (ES: calculated as the difference between mean on-treatment and baseline BM frequency, divided by the standard deviation of the baseline), and related confidence intervals. Results: There were 135 patients with CS, with a mean age of 63.6 years and mean baseline BM frequency of 5.7 BM/day. Anchor-based analyses indicated significant differences in BM frequency between adequate relief groups at Week 12 (ES: -1.58 vs. -0.79; p = 0.014), responders and non-responders on the EORTC QLQ-C30 Diarrhea Symptoms domain (ES: -1.24 vs. -0.59; p < 0.0001), and responders and non-responders on the EORTC GI.NET21 GI Symptoms Domain (ES: -1.49 vs. -0.75; p = 0.0053). These corresponded to BM frequency reductions of 1.7-1.9 BM/day, or ≥ 30%. Conclusions: Results of this study indicated that patients with CS experienced clinically meaningful reductions in BM frequency of ≥ 30% over the course of 12 weeks.

Telotristat Ethyl, a Tryptophan Hydroxylase Inhibitor for the Treatment of Carcinoid Syndrome

Purpose

Preliminary studies suggested that telotristat ethyl, a tryptophan hydroxylase inhibitor, reduces bowel movement (BM) frequency in patients with carcinoid syndrome. This placebo-controlled phase III study evaluated telotristat ethyl in this setting.

Patients and Methods

Patients (N = 135) experiencing four or more BMs per day despite stable-dose somatostatin analog therapy received (1:1:1) placebo, telotristat ethyl 250 mg, or telotristat ethyl 500 mg three times per day orally during a 12-week double-blind treatment period. The primary end point was change from baseline in BM frequency. In an open-label extension, 115 patients subsequently received telotristat ethyl 500 mg.

Results

Estimated differences in BM frequency per day versus placebo averaged over 12 weeks were –0.81 for telotristat ethyl 250 mg ( P < .001) and ‒0.69 for telotristat ethyl 500 mg ( P < .001). At week 12, mean BM frequency reductions per day for placebo, telotristat ethyl 250 mg, and telotristat ethyl 500 mg were –0.9, –1.7, and –2.1, respectively. Responses, predefined as a BM frequency reduction ≥ 30% from baseline for ≥ 50% of the double-blind treatment period, were observed in 20%, 44%, and 42% of patients given placebo, telotristat ethyl 250 mg, and telotristat ethyl 500 mg, respectively. Both telotristat ethyl dosages significantly reduced mean urinary 5-hydroxyindole acetic acid versus placebo at week 12 ( P < .001). Mild nausea and asymptomatic increases in gamma-glutamyl transferase were observed in some patients receiving telotristat ethyl. Follow-up of patients during the open-label extension revealed no new safety signals and suggested sustained BM responses to treatment.

Conclusion

Among patients with carcinoid syndrome not adequately controlled by somatostatin analogs, treatment with telotristat ethyl was generally safe and well tolerated and resulted in significant reductions in BM frequency and urinary 5-hydroxyindole acetic acid.

KRAS and Combined KRAS/TP53 Mutations in Locally Advanced Rectal Cancer are Independently Associated with Decreased Response to Neoadjuvant Therapy

BACKGROUND

The response of rectal cancers to neoadjuvant chemoradiation (CRT) is variable, but tools to predict response remain lacking. We evaluated whether KRAS and TP53 mutations are associated with pathologic complete response (pCR) and lymph node metastasis after adjusting for neoadjuvant regimen.

METHODS

Retrospective analysis of 229 pretreatment biopsies from patients with stage II/III rectal cancer was performed. All patients received CRT. Patients received 0-8 cycles of FOLFOX either before or after CRT, but prior to surgical excision. A subset was analyzed to assess concordance between mutation calls by Sanger Sequencing and a next-generation assay.

RESULTS

A total of 96 tumors (42 %) had KRAS mutation, 150 had TP53 mutation (66 %), and 59 (26 %) had both. Following neoadjuvant therapy, 59 patients (26 %) achieved pCR. Of 133 KRAS wild-type tumors, 45 (34 %) had pCR, compared with 14 of 96 (15 %) KRAS mutant tumors (p = .001). KRAS mutation remained independently associated with a lower pCR rate on multivariable analysis after adjusting for clinical stage, CRT-to-surgery interval and cycles of FOLFOX (OR 0.34; 95 % CI 0.17-0.66, p < .01). Of 29 patients with KRAS G12V or G13D, only 2 (7 %) achieved pCR. Tumors with both KRAS and TP53 mutation were associated with lymph node metastasis. The concordance between platforms was high for KRAS (40 of 43, 93 %).

CONCLUSIONS

KRAS mutation is independently associated with a lower pCR rate in locally advanced rectal cancer after adjusting for variations in neoadjuvant regimen. Genomic data can potentially be used to select patients for "watch and wait" strategies.

The spectrum of neuroendocrine tumors: histologic classification, unique features and areas of overlap

Neuroendocrine neoplasms are diverse in terms of sites of origin, functional status, and degrees of aggressiveness. This review will introduce some of the common features of neuroendocrine neoplasms and will explore the differences in pathology, classification, biology, and clinical management between tumors of different anatomic sites, specifically, the lung, pancreas, and prostate. Despite sharing neuroendocrine differentiation and histologic evidence of the neuroendocrine phenotype in most organs, well-differentiated neuroendocrine tumors (WD-NETs) and poorly differentiated neuroendocrine carcinomas (PD-NECs) are two very different families of neoplasms. WD-NETs (grade 1 and 2) are relatively indolent (with a natural history that can evolve over many years or decades), closely resemble non-neoplastic neuroendocrine cells, and demonstrate production of neurosecretory proteins, such as chromogranin A. They arise in the lungs and throughout the gastrointestinal tract and pancreas, but WD-NETs of the prostate gland are uncommon. Surgical resection is the mainstay of therapy, but treatment of unresectable disease depends on the site of origin. In contrast, PD-NECs (grade 3, small cell or large cell) of all sites often demonstrate alterations in P53 and Rb, exhibit an aggressive clinical course, and are treated with platinum-based chemotherapy. Only WD-NETs arise in patients with inherited neuroendocrine neoplasia syndromes (e.g., multiple endocrine neoplasia type 1), and some common genetic alterations are site-specific (e.g., TMPRSS2-ERG gene rearrangement in PD-NECs arising in the prostate gland). Advances in our understanding of the molecular basis of NETs should lead to new diagnostic and therapeutic strategies and is an area of active investigation.

First-in-Human Phase I Study of GSK2126458, an Oral Pan-Class I Phosphatidylinositol-3-Kinase Inhibitor, in Patients with Advanced Solid Tumor Malignancies

PURPOSE

GSK2126458 (GSK458) is a potent inhibitor of PI3K (α, β, γ, and δ), with preclinical studies demonstrating broad antitumor activity. We performed a first-in-human phase I study in patients with advanced solid tumors.

MATERIALS AND METHODS

Patients received oral GSK458 once or twice daily in a dose-escalation design to define the maximum tolerated dose (MTD). Expansion cohorts evaluated pharmacodynamics, pharmacokinetics, and clinical activity in histologically and molecularly defined cohorts.

RESULTS

One hundred and seventy patients received doses ranging from 0.1 to 3 mg once or twice daily. Dose-limiting toxicities (grade 3 diarrhea,n= 4; fatigue and rash,n= 1) occurred in 5 patients (n= 3 at 3 mg/day). The MTD was 2.5 mg/day (MTD with twice daily dosing undefined). The most common grade ≥3 treatment-related adverse events included diarrhea (8%) and skin rash (5%). Pharmacokinetic analyses demonstrated increased duration of drug exposure above target level with twice daily dosing. Fasting insulin and glucose levels increased with dose and exposure of GSK458. Durable objective responses (ORs) were observed across multiple tumor types (sarcoma, kidney, breast, endometrial, oropharyngeal, and bladder cancer). Responses were not associated withPIK3CAmutations (OR rate: 5% wild-type vs. 6% mutant).

CONCLUSIONS

Although the MTD of GSK458 was 2.5 mg once daily, twice-daily dosing may increase duration of target inhibition. Fasting insulin and glucose levels served as pharmacodynamic markers of drug exposure. Select patients achieved durable responses; however,PIK3CAmutations were neither necessary nor predictive of response. Combination treatment strategies and novel biomarkers may be needed to optimally target PI3K.

Neuroendocrine tumors, version 1.2015

Neuroendocrine tumors (NETs) comprise a broad family of tumors that may or may not be associated with symptoms attributable to hormonal hypersecretion. The NCCN Clinical Practice Guidelines in Oncology for Neuroendocrine Tumors discuss the diagnosis and management of both sporadic and hereditary NETs. This selection from the guidelines focuses on sporadic NETs of the pancreas, gastrointestinal tract, lung, and thymus.

A phase I dose-escalation study to assess safety, tolerability, pharmacokinetics, and preliminary efficacy of the dual mTORC1/mTORC2 kinase inhibitor CC-223 in patients with advanced solid tumors or multiple myeloma

BACKGROUND

The mammalian target of rapamycin (mTOR) pathway is essential for tumor development, yet mTOR inhibitors have yielded modest results. This phase 1 study investigated the mTORC1/mTORC2 inhibitor CC-223 in patients with advanced cancer.

METHODS

Patients with advanced solid tumors or multiple myeloma received an initial dose of 7.5-60 mg of CC-223, followed by oral daily dosing in 28-day cycles until disease progression. The primary objective was to determine the safety, tolerability, nontolerated dosage, maximum tolerated dosage (MTD), and preliminary pharmacokinetic profile. Secondary objectives were to evaluate pharmacodynamic effects and to describe preliminary efficacy.

RESULTS

Twenty-eight patients were enrolled and received ≥1 dose of CC-223. The most common treatment-related grade 3 adverse events were hyperglycemia, fatigue, and rash. Four patients had dose-limiting toxicities, including hyperglycemia, rash, fatigue, and mucositis. Therefore, 45 mg/d was determined to be the MTD. The pharmacokinetics of CC-223 demonstrated a mean terminal half-life ranging from 4.86 to 5.64 hours and maximum observed plasma concentration ranging from 269 to 480 ng/mL in patients who received CC-223 ≥45 mg/d. Phosphorylation of mTORC1/mTORC2 pathway biomarkers in blood cells was inhibited by CC-223 ≥30 mg/d with an exposure-response relationship. Best responses included 1 partial response (breast cancer; response duration 220 days; 30-mg/d cohort), stable disease (8 patients across ≥15 mg/d cohorts; response duration range, 36-168 days), and progressive disease (12 patients). The disease control rate was 32%.

CONCLUSIONS

CC-223 was tolerable, with manageable toxicities. Preliminary antitumor activity, including tumor regression, and evidence of mTORC1/mTORC2 pathway inhibition were observed.

Intratumoral myeloid cells regulate responsiveness and resistance to antiangiogenic therapy

Antiangiogenic therapy is commonly used in the clinic, but its beneficial effects are short-lived, leading to tumor relapse within months. Here, we found that the efficacy of angiogenic inhibitors targeting the VEGF/VEGFR pathway was dependent on induction of the angiostatic and immune-stimulatory chemokine CXCL14 in mouse models of pancreatic neuroendocrine and mammary tumors. In response, tumors reinitiated angiogenesis and immune suppression by activating PI3K signaling in all CD11b+ cells, rendering tumors nonresponsive to VEGF/VEGFR inhibition. Adaptive resistance was also associated with an increase in Gr1+CD11b+ cells, but targeting Gr1+ cells was not sufficient to further sensitize angiogenic blockade because tumor-associated macrophages (TAMs) would compensate for the lack of such cells and vice versa, leading to an oscillating pattern of distinct immune-cell populations. However, PI3K inhibition in CD11b+ myeloid cells generated an enduring angiostatic and immune-stimulatory environment in which antiangiogenic therapy remained efficient.

Telotristat etiprate, a novel serotonin synthesis inhibitor, in patients with carcinoid syndrome and diarrhea not adequately controlled by octreotide

Serotonin produced by neuroendocrine tumors is believed to be a principal cause of the diarrhea in carcinoid syndrome. We assessed the safety and efficacy of telotristat etiprate, an oral serotonin synthesis inhibitor, in patients with diarrhea associated with carcinoid syndrome. In this prospective, randomized study, patients with evidence of carcinoid tumor and ≥4 bowel movements (BMs)/day despite stable-dose octreotide LAR depot therapy were enrolled in sequential, escalating, cohorts of four patients per cohort. In each cohort, one patient was randomly assigned to placebo and three patients to telotristat etiprate, at 150, 250, 350, or 500 mg three times a day (tid). In a subsequent cohort, one patient was assigned to placebo and six patients to telotristat etiprate 500 mg tid. Patients were assessed for safety, BM frequency (daily diary), 24 h urinary 5-hydroxyindoleacetic acid (u5-HIAA), and adequate relief of carcinoid gastrointestinal symptoms (using a weekly questionnaire). Twenty-three patients were treated: 18 received telotristat etiprate and five received placebo. Adverse events were generally mild. Among evaluable telotristat etiprate-treated patients, 5/18 (28%) experienced a ≥30% reduction in BM frequency for ≥2 weeks, 9/16 (56%) experienced biochemical response (≥50% reduction or normalization in 24-h u5-HIAA) at week 2 or 4, and 10/18 (56%) reported adequate relief during at least 1 of the first 4 weeks of treatment. Similar activity was not observed in placebo-treated patients. Telotristat etiprate was well tolerated. Our observations suggest that telotristat etiprate has activity in controlling diarrhea associated with carcinoid syndrome. Further studies confirming these findings are warranted.

B cells regulate macrophage phenotype and response to chemotherapy in squamous carcinomas

B cells foster squamous cell carcinoma (SCC) development through deposition of immunoglobulin-containing immune complexes in premalignant tissue and Fcγ receptor-dependent activation of myeloid cells. Because human SCCs of the vulva and head and neck exhibited hallmarks of B cell infiltration, we examined B cell-deficient mice and found reduced support for SCC growth. Although ineffective as a single agent, treatment of mice bearing preexisting SCCs with B cell-depleting αCD20 monoclonal antibodies improved response to platinum- and Taxol-based chemotherapy. Improved chemoresponsiveness was dependent on altered chemokine expression by macrophages that promoted tumor infiltration of activated CD8(+) lymphocytes via CCR5-dependent mechanisms. These data reveal that B cells, and the downstream myeloid-based pathways they regulate, represent tractable targets for anticancer therapy in select tumors.

Neuroendocrine tumors

Neuroendocrine tumors comprise a broad family of tumors, the most common of which are carcinoid and pancreatic neuroendocrine tumors. The NCCN Neuroendocrine Tumors Guidelines discuss the diagnosis and management of both sporadic and hereditary neuroendocrine tumors. Most of the recommendations pertain to well-differentiated, low- to intermediate-grade tumors. This updated version of the NCCN Guidelines includes a new section on pathology for diagnosis and reporting and revised recommendations for the surgical management of neuroendocrine tumors of the pancreas.

Abstract 4391: CD20 as a target for therapy in solid tumors

Using the K14-HPV16 mouse model of squamous carcinogenesis (SCC), we previously reported that B cells foster neoplastic progression through deposition of immunoglobulin complexes in premalignant tissue via Fcα receptor-dependent activation of recruited myeloid cells. Here we evaluated therapeutic interventions targeting these pathways in preclinical trials through administration of depleting αCD20 antibody and small molecule inhibitor of Syk kinase. Both approaches harbored efficacy in preventing premalignant progression to the dysplastic/carcinoma in situ state. Screening a diverse spectrum of human solid tumors revealed SCCs of the vulva, head and neck, as well as pancreatic ductal adenocarcinomas (PDAC) as scoring positively for “signatures” of B cell or plasma cell infiltration, i.e. Ig or CD20 mRNA expression, thereby identifying carcinomas potentially amenable to anti-B cell therapies. Accordingly, B cell-deficient mice failed to support growth of either transplantable orthotopic SCC or PDAC. While administration of αCD20 mAB as a single agent was inefficient in impeding growth of preexisting SCCs, when delivered in combination with cytotoxic chemotherapy, e.g., paclitaxel, carboplatin or cisplatin, αCD20 mAb significantly improved chemotherapeutic response and improved survival by a mechanism dependent on CD8+ T cells. These data reveal that blocking protumorigenic programs regulating by humoral immunity, in combination with chemotherapy, effectively reprograms the tumor immune microenvironment and improves outcome. The authors acknowledge generous support from the NIH/NCI (R01CA130980, R01CA13256, R01CA140943, R01CA15531), the Department of Defense (W81XWH-09-1-0342, W81XWH-10-BCRP-EOHS-EXP) and the Susan G Komen Foundation (KG111084)

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4391. doi:1538-7445.AM2012-4391