Context: Patients with progressive metastatic pheochromocytomas (PHEOs) or sympathetic paragangliomas (SPGLs) face a dismal prognosis. Current systemic therapies are limited. Objectives: The primary end point was progression-free survival determined by RECIST 1.1 criteria or positron emission tomography with [¹⁸F]fluorodeoxyglucose/computed tomography ([¹⁸F]FDG-PET/CT), in the absence of measurable soft tissue targets. Secondary endpoints were tumor response according to RECIST criteria version 1.1 or FDG uptake, blood pressure control, and safety. Design: We conducted a retrospective review of medical records of patients with metastatic PHEO/SPGL treated with sunitinib from December 2007 through December 2011. An intention-to-treat analysis was performed. Patients and Setting: Seventeen patients with progressive metastatic PHEO/SPGLs treated at the Institut Gustave-Roussy and MD Anderson Cancer Center. Interventions: Patients treated with sunitinib. Results: According to RECIST 1.1, eight patients experienced clinical benefit; three experienced partial response, and five had stable disease, including four with predominant skeletal metastases that showed a 30% or greater reduction in glucose uptake on [¹⁸F]FDG-PET/CT. Of 14 patients who had hypertension, six became normotensive and two discontinued antihypertensives. One patient treated with sunitinib and rapamycin experienced a durable benefit beyond 36 months. The median overall survival from the time sunitinib was initiated was 26.7 months with a progression-free survival of 4.1 months (95% confidence interval = 1.4–11.0). Most patients who experienced a clinical benefit were carriers of SDHB mutations. Conclusion: Sunitinib is associated with tumor size reduction, decreased [¹⁸F]FDG-PET/CT uptake, disease stabilization, and hypertension improvement in some patients with progressive metastatic PHEO/PGL. Prospective multi-institutional clinical trials are needed to determine the true benefits of sunitinib.

BACKGROUND: The objective of this study was to evaluate the clinical benefits of systemic chemotherapy for patients with metastatic pheochromocytomas or sympathetic paragangliomas by assessing reductions in tumor size and blood pressure and improvements in overall survival (OS).METHODS: The authors retrospectively reviewed the medical records of patients with metastatic pheochromocytomas‐sympathetic paragangliomas who had received chemotherapy at The University of Texas MD Anderson Cancer Center.RESULTS: Clinical benefit and OS were assessed. Of 54 patients who received chemotherapy, 52 patients were evaluable for response. Seventeen patients (33%) experienced a response, which was defined as decreased or normalized blood pressure/decreased number and dosage of antihypertensive medications and/or reduced tumor size after the first chemotherapy regimen. The median OS was 6.4 years (95% confidence interval [CI], 5.2‐16.4 years) for responders and 3.7 years (95% CI, 3.0‐7.5 years) for nonresponders. Among the patients who had synchronous metastatic disease, a positive response at 1 year after the start of chemotherapy was associated with a trend toward longer OS (log‐rank test; P = .095). In a multivariate Cox proportional hazards model, the effect of response to chemotherapy on OS was significant (hazard ratio, 0.22; 95% CI, interval: 0.05‐1.0; P = .05). All responders had received dacarbazine and cyclophosphamide. Vincristine was included for 14 responders, and doxorubicin was included for 12 responders. The clinical factors that predicted response to chemotherapy could not be identified.CONCLUSIONS: The current results indicted that chemotherapy may decrease tumor size and facilitate blood pressure control in approximately 33% of patients with metastatic pheochromocytoma‐sympathetic paraganglioma. These patients exhibited longer survival. Cancer 2011. © 2011 American Cancer Society.

Bone metastases (BM) can cause severe pain, spinal cord compression, pathological fractures, and/or hypercalcemia. These skeletal-related events (SREs) may cause immobilization, loss of independence, poor quality of life, and reduced survival. There is limited information on the clinical effects of BM and SREs in patients with malignant pheochromocytoma or sympathetic paraganglioma (PHEO/sPGL). We studied the prevalence and clinical characteristics of BM and SREs in patients with PHEO/sPGL and investigated the risk factors for SRE development. Using a large institutional database, we conducted a retrospective study of 128 patients with malignant PHEO/sPGL at The University of Texas MD Anderson Cancer Center from 1967 through 2011. Of the patients, 91 (71%) had BM, and 57 of these (63%) developed metachronous BM at a median time of 3.4 years (range, 5 months to 23 years) after the primary tumor diagnosis. Metastatic disease was confined exclusively to the skeleton in 26 of 128 (20%) patients. Sufficient information to assess SRE occurrence was available for 67 patients, and 48 of 67 (72%) patients had at least 1 SRE. The median overall survival for the 128 patients was 12 years for patients with only BM, 7.5 years for patients with nonosseous metastases, and 5 years for patients with both BM and nonosseous metastases (log rank test P value = .005). We were unable to identify factors predictive of SRE development, but the occurrence of a first SRE was associated with the development of subsequent SREs in 48% of subjects. In responsive patients, the use of systemic therapy was associated with fewer SREs (P < .0001). BM and SREs are frequent in patients with malignant PHEO/sPGL. SREs often develop shortly after the diagnosis of BM; severe pain is the most frequent SRE. These patients should be followed long-term by a multidisciplinary team to promptly identify the need for medical or surgical intervention.

Tumors driven by deficiency of the VHL gene product, which is involved in degradation of the hypoxia-inducible factor subunit 2 alpha (HIF2α), are natural candidates for targeted inhibition of this pathway. Belzutifan, a highly specific and well-tolerated HIF2α inhibitor, recently received FDA approval for the treatment of nonmetastatic renal cell carcinomas, pancreatic neuroendocrine tumors, and central nervous system hemangioblastomas from patients with von Hippel–Lindau disease, who carry VHL germline mutations. Such approval is a milestone in oncology; however, the full potential, and limitations, of HIF2α inhibition in the clinic are just starting to be explored. Here we briefly recapitulate the molecular rationale for HIF2α blockade in tumors and review available preclinical and clinical data, elaborating on mutations that might be particularly sensitive to this approach. We also outline some emerging mechanisms of intrinsic and acquired resistance to HIF2α inhibitors, including acquired mutations of the gatekeeper pocket of HIF2α and its interacting partner ARNT. Lastly, we propose that the high efficacy of belzutifan observed in tumors with genetically driven hypoxia caused by VHL mutations suggests that a focus on other mutations that similarly lead to HIF2α stabilization, such as those occurring in neuroendocrine tumors with disruptions in the tricarboxylic acid cycle (SDHA/B/C/D, FH, MDH2, IDH2), HIF hydroxylases (EGLN/PHDs), and the HIF2α-encoding gene, EPAS1, are warranted. Open in new tab Download slide

Context: von Hippel-Lindau disease is characterized by highly vascularized tumors of multiple organs. Evidence Acquisition: We present a patient with von Hippel-Lindau disease with multiple renal and pancreatic tumors and a malignant pheochromocytoma infiltrative of the sacrum and associated with lymph nodule metastases. The pheochromocytoma expressed high protein level of vascular endothelial growth factor and platelet-derived growth factor-β receptor. The patient presented with a poor performance status, severe pelvic pain, weight loss, and manifestations of catecholamine excess. Evidence Synthesis: Treatment against malignant pheochromocytoma with surgery, chemotherapy, or participation in clinical trials was not feasible because of the patient’s poor performance status, the presence of multiple tumors, and the extension of the pheochromocytoma into the bones. Patient was treated with sunitinib, a potent tyrosine kinase inhibitor of vascular endothelial growth factor, platelet-derived growth factor, RET, c-KIT, and FLT-3 receptors. Six months of treatment with sunitinib was associated with normalization of the patient’s performance status and blood pressure, absence of symptoms of catecholamine excess, weight gain, disappearance of pain, shrinkage of each of the tumors (50% in the largest renal tumor, 38% in the largest islet cell tumor, 21% in the pelvic malignant pheochromocytoma), and reduction of plasma normetanephrines and chromogranin A. Conclusion: This study provides evidence that targeting tyrosine kinase receptors such as the vascular endothelial growth factor pathway and the platelet-derived growth factor-β receptor may have value in the treatment of VHL-related tumors including pheochromocytoma.