Margetuximab with retifanlimab as first-line therapy in HER2+/PD-L1+ unresectable or metastatic gastroesophageal adenocarcinoma: MAHOGANY cohort A

Background

Human epidermal growth factor receptor 2 (HER2)-positive metastatic gastric and gastroesophageal adenocarcinoma (GEA) is globally treated with chemotherapy plus trastuzumab. Novel therapeutic strategies strive to not only optimize efficacy, but also limit toxicities. In MAHOGANY cohort A, margetuximab, an Fc-engineered, anti-HER2 monoclonal antibody (mAb) was combined with retifanlimab, an anti-programmed cell death protein 1 mAb, in the first-line HER2-positive/programmed death-ligand 1 (PD-L1)-positive GEA.

Patients and methods

MAHOGANY cohort A part 1 is a single-arm trial to evaluate margetuximab plus retifanlimab in patients with HER2 immunohistochemistry 3+, PD-L1-positive (combined positive score ≥1%), and non-microsatellite instability-high tumors. Primary objectives for cohort A were safety/tolerability and the confirmed objective response rate (ORR).

Results

As of 3 August 2021, 43 patients were enrolled and received margetuximab/retifanlimab. Nine grade 3 treatment-related adverse events (TRAEs) were reported in eight (18.6%) patients and eight serious TRAEs in seven (16.3%) patients. There were no grade 4/5 TRAEs. Three patients discontinued margetuximab/retifanlimab because of immune-related adverse events. The ORR by independent assessment was 53% [21/40 (95% confidence interval (CI) 36.1-68.5)], with a median duration of response of 10.3 months (95% CI 4.6-not evaluable); disease control rate was 73% [29/40 (95% CI 56.1-85.4)]. The study sponsor discontinued the study in advance of the planned enrollment when it became apparent that the study design would no longer meet the requirements for drug approval because of recent advances in the treatment of GEA.

Conclusions

The chemotherapy-free regimen of combined margetuximab/retifanlimab as first-line treatment in double biomarker-selected patients demonstrated a favorable toxicity profile compared with historical outcomes using chemotherapy plus trastuzumab. The ORR observed in this study compares favorably versus ORR observed with other chemotherapy-free approaches.

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The margetuximab/retifanlimab regimen has a favorable toxicity profile versus historical chemotherapy-based regimens in GEA.

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The margetuximab/retifanlimab regimen as first-line therapy for GEA met the prespecified boundary for antitumor activity.

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The 53% ORR [21/40 (95% CI 36.1-68.5)] in the combined regimen compared favorably with other chemotherapy-free approaches.

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Median duration of response was 10.3 months (95% CI 4.57-not evaluable) and disease control rate was 73% [29/40 (95% CI 56.1-85.4)].

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The study was discontinued for business reasons as chemotherapy-based regimens remain the dominant therapy for GEA.

Osteoclast-Like Giant Cell Tumors of the Pancreas: Clinical Characteristics, Genetic Testing, and Treatment Modalities

OBJECTIVES

This study sought to better characterize patient characteristics, treatment options, and outcomes for osteoclast-like giant cell carcinoma of the pancreas, a rare subtype of pancreatic adenocarcinoma.

METHODS

This is a retrospective study of all patients with osteoclast-like giant cell carcinoma of pancreatic origin treated at Mayo Clinic from 2000 to present. Baseline patient characteristics, treatment modalities utilized, and outcomes were compiled. Overall survival (OS) and progression-free survival were assessed using Kaplan-Meier analysis with a significance level of P ≤ 0.05.

RESULTS

Fifteen patients met criteria for inclusion. Four patients had distant metastases at diagnosis, the remaining 11 with locoregional disease. Median OS for the entire cohort was 11 months. Metastatic disease was associated with significantly shorter OS (3.5 vs 14.1 months; P = 0.005). Three patients had no evidence of disease at time of analysis; all 3 were treated with complete resection followed by adjuvant chemotherapy.

CONCLUSIONS

Osteoclast-like giant cell carcinoma of the pancreas is an aggressive malignancy with poor prognosis. For patients with locoregional disease, surgical resection followed by adjuvant chemoradiation may play a role in extended disease-free survival. Metastatic disease presents a challenging entity to treat with little data to support any effective chemotherapy regimens.

Neuroendocrine Carcinoma of the Anus and Rectum: Patient Characteristics and Treatment Options

INTRODUCTION

Anorectal neuroendocrine carcinomas (NECs) are uncommon malignancies with poor prognosis. Consensus guidelines exist for treating extrapulmonary NEC. However, limited data is available to guide treatment for anorectal NEC. In this study, we sought to review the clinical characteristics and outcomes of patients with NEC of the rectum and/or anus at Mayo Clinic.

PATIENTS AND METHODS

This is a retrospective study of all patients with the diagnosis of NEC of the anus and/or rectum treated across Mayo Clinic sites since 2000. Baseline patient characteristics, tumor pathology, imaging profiles, treatment strategies utilized, and survival outcomes were analyzed. Kaplan-Meier analysis was used with a significance level of P < .05.

RESULTS

The study included a total of 38 patients with primary NEC of the anus and/or rectum. The median age at diagnosis was 55.5 years. The median follow-up was 18.8 months. Fifteen patients had locoregional disease (LRD) at diagnosis. The remaining 23 had metastatic disease. Overall survival was significantly shorter in patients with LRD compared with those with metastatic disease at diagnosis (18.1 vs. 13.8 months; P = .039). The majority (n = 11) of patients with LRD were treated with concurrent chemoradiation therapy, and 10 underwent surgical resection of the primary tumor. The majority (13/15) of patients with LRD progressed, with the majority (11/15) of progressions being distant. The median progression-free survival for patients with LRD was 5.7 months (1-year progression-free survival, 26.7%).

CONCLUSION

Anorectal NEC is an aggressive malignancy with poor prognosis requiring multidisciplinary discussion. In addition, the systemic nature of anorectal NEC with distant recurrences in LRD and poor outcomes in metastatic disease emphasizes the need to further develop better systemic treatment options that can potentially improve outcomes in NEC.

Epidemiology of Cholangiocarcinoma; United States Incidence and Mortality Trends

BACKGROUND

Cholangiocarcinoma is an aggressive malignancy with few available studies assessing incidence and mortality. In this study, we aim to investigate trends of incidence and mortality in a large nation-wide epidemiologic study.

METHODS

We used SEER 18 database to study cholangiocarcinoma cases in the US during 2000-2015. Incidence and mortality rates of cholangiocarcinoma were calculated by race and were expressed by 1,000,000 person-years. Annual percent change (APC) was calculated using joinpoint regression software.

RESULTS

We reviewed 16,189 patients with cholangiocarcinoma, of which 64.4% were intrahepatic. Most patients were whites (78.4%), males (51.3%), and older than 65 years (63%). A total of 13,121 patients died of cholangiocarcinoma during the study period. Cholangiocarcinoma incidence and mortality were 11.977 and 10.295 and were both higher among Asians, males, and individuals older than 65 years. Incidence rates have significantly increased over the study period (APC=5.063%, P<.001), while mortality increased significantly over the study period (APC=5.964%, P<.001), but decreased after 2013 (APC=-25.029, P<.001).

CONCLUSION

The incidence and mortality of cholangiocarcinoma were increasing in the study period with significant observed disparities based on race and gender.

Clinical review: Drugs commonly associated with weight change: a systematic review and meta-analysis

CONTEXT

Various drugs affect body weight as a side effect.

OBJECTIVE

We conducted this systematic review and meta-analysis to summarize the evidence about commonly prescribed drugs and their association with weight change.

DATA SOURCES

MEDLINE, DARE, and the Cochrane Database of Systematic Reviews were searched to identify published systematic reviews as a source for trials.

STUDY SELECTION

We included randomized trials that compared an a priori selected list of drugs to placebo and measured weight change.

DATA EXTRACTION

We extracted data in duplicate and assessed the methodological quality using the Cochrane risk of bias tool.

RESULTS

We included 257 randomized trials (54 different drugs; 84 696 patients enrolled). Weight gain was associated with the use of amitriptyline (1.8 kg), mirtazapine (1.5 kg), olanzapine (2.4 kg), quetiapine (1.1 kg), risperidone (0.8 kg), gabapentin (2.2 kg), tolbutamide (2.8 kg), pioglitazone (2.6 kg), glimepiride (2.1 kg), gliclazide (1.8 kg), glyburide (2.6 kg), glipizide (2.2 kg), sitagliptin (0.55 kg), and nateglinide (0.3 kg). Weight loss was associated with the use of metformin (1.1 kg), acarbose (0.4 kg), miglitol (0.7 kg), pramlintide (2.3 kg), liraglutide (1.7 kg), exenatide (1.2 kg), zonisamide (7.7 kg), topiramate (3.8 kg), bupropion (1.3 kg), and fluoxetine (1.3 kg). For many other remaining drugs (including antihypertensives and antihistamines), the weight change was either statistically nonsignificant or supported by very low-quality evidence.

CONCLUSIONS

Several drugs are associated with weight change of varying magnitude. Data are provided to guide the choice of drug when several options exist and institute preemptive weight loss strategies when obesogenic drugs are prescribed.