Cabozantinib in patients with unresectable and progressive metastatic phaeochromocytoma or paraganglioma (the Natalie Trial): a single-arm, phase 2 trial.

BACKGROUND: Metastatic phaeochromocytomas and paragangliomas (MPPGs) are orphan diseases. Up to 50% of MPPGs are associated with germline pathogenic variants of the SDHB gene. These tumours and many non-familial MPPGs exhibit a phenotype that is characterised by abnormal angiogenesis. We aimed to assess the activity and safety of cabozantinib, an antiangiogenic multi-tyrosine kinase inhibitor, in patients with MPPGs. METHODS: The Natalie Trial is a single-arm, phase 2 clinical trial being conducted at The University of Texas MD Anderson Cancer Center (Houston, TX, USA). Patients aged 18 years or older with histologically confirmed, progressive, and unresectable MPPGs, with an Eastern Cooperative Oncology Group performance status of 0-2, were treated with oral cabozantinib 60 mg/day. The primary endpoint was the investigator-assessed overall response rate per the Response Evaluation Criteria in Solid Tumours version 1.1 criteria. All outcomes were assessed in all evaluable participants who received any amount of study treatment. The trial is registered with ClinicalTrials.gov (NCT02302833) and is active but not recruiting. FINDINGS: From March 10, 2015, to May 11, 2021, 17 patients (13 male participants and four female participants) were enrolled. The median follow-up was 25 months (IQR 18-49). The overall response rate was 25·0% (95% CI 7·3-52·4; four of 16 patients). Seven grade 3 adverse events were reported in six patients, including single cases of hand-and-foot syndrome, hypertension, rectal fistula, QT prolongation, and asymptomatic hypomagnesaemia, and two cases of asymptomatic elevations of amylase and lipase. There were no grade 4 adverse events and no patient died on-study. INTERPRETATION: Cabozantinib shows promising activity in patients with MPPGs. FUNDING: Team NAT Foundation, Margaret Cazalot, and Clarence P Cazalot.

Belzutifan, a Potent HIF2α Inhibitor, in the Pacak-Zhuang Syndrome.

The integration of genomic testing into clinical care enables the use of individualized approaches to the management of rare diseases. We describe the use of belzutifan, a potent and selective small-molecule inhibitor of the protein hypoxia-inducible factor 2α (HIF2α), in a patient with polycythemia and multiple paragangliomas (the Pacak-Zhuang syndrome). The syndrome was caused in this patient by somatic mosaicism for an activating mutation in EPAS1. Treatment with belzutifan led to a rapid and sustained tumor response along with resolution of hypertension, headaches, and long-standing polycythemia. This case shows the application of a targeted therapy for the treatment of a patient with a rare tumor-predisposition syndrome. (Funded by the Morin Family Fund for Pediatric Cancer and Alex's Lemonade Stand Foundation.).

NDUFA4 promotes the progression of head and neck paraganglioma by inhibiting ferroptosis.

NDUFA4 is a component of respiratory chain-oxidative phosphorylation pathway. NDUFA4 is highly expressed in tumor tissues, but little is known about the function of NDUFA4 in head and neck paraganglioma (HNPGL). We examined NDUFA4 expression in tissues from 10 HNPGL patients and 6 controls using qRT-PCR and Western blotting. NDUFA4 knockdown PGL-626 cells were established by using lentivirus infection and puromycin screening. Cell viability, ATP production, lipid reactive oxygen species, and mitochondrial membrane potential assays were performed to investigate the ferroptotic effects in NDUFA4 deficiency HNPGL cancer cells. Xenograft mouse model was created to detect the synergetic antitumor action between NDUFA4 deficiency and Metformin. NDUFA4 was upregulated in tumor tissues of HNPGL patients. NDUFA4 knockdown impaired the assembly of mitochondrial respiratory chain complexes and decreased the production of ATP and reduced cancer cell viability. Mechanistically, NDUFA4 knockdown increased cell ferroptosis, which further promoted Metformin-induced ferroptosis in PGL-626 cells. Therefore, NDUFA4 deficiency enhanced Metformin-mediated inhibition of the HNPGL progression in mice. In conclusion, NDUFA4 promotes the progression of HNPGL, and NDUFA4 knockdown enhances Metformin-mediated inhibition of the HNPGL progression in a mouse model.

New Directions in Treatment of Metastatic or Advanced Pheochromocytomas and Sympathetic Paragangliomas: an American, Contemporary, Pragmatic Approach.

PURPOSE OF REVIEW: Multiple therapies with novel mechanisms have been explored in clinical trials for the treatment of metastatic pheochromocytomas and paragangliomas. We review current and future therapies for this disease and provide guidance on how and when to prescribe them based on tumor progression, clinical manifestations, molecular features, and social factors. RECENT FINDINGS: Approximately 60-70% of metastatic pheochromocytomas and paragangliomas express the noradrenaline transporter in their cell membranes. High specific activity iodine-131 metaiodobenzylguanidine has been recently approved by the US Food and Drug Administration for the treatment of metastatic pheochromocytomas and paragangliomas that express the noradrenaline transporter, in patients aged ≥ 12 years. More than 90% of patients treated with this medication exhibit clinical benefits. However, other therapies with novel mechanisms of action are needed to help all patients with this disease. Treatment of metastatic pheochromocytomas and paragangliomas is recommended based on the severity of symptoms, the progression of the disease, and the patient's performance status. Currently available therapies include surgery; systemic chemotherapy with cyclophosphamide, vincristine, and dacarbazine, or with temozolomide; high specific activity iodine-131 metaiodobenzylguanidine; peptide receptor radionuclide therapy; immunotherapy; tyrosine kinase inhibitors; and hypoxia-inducible factor 2 alpha inhibitors. Financial and social factors such as health insurance coverage and disparities also impact current clinical practice in the USA.

Predictors of prolonged hypotension requiring vasopressor support after resection of pheochromocytoma and paraganglioma.

OBJECTIVE: Prolonged hypotension is a common complication after resection of pheochromocytoma (PCC) or paraganglioma (PGL). The objective of our study was to identify preoperative or intraoperative clinical factors that can predict prolonged hypotension after PCC/PGL resection. PATIENTS AND METHODS: A total of 414 patients who underwent resection of PCC or PGL at our institution between January 2013 and January 2020 were included. Patients were divided into two groups according to whether or not vasopressor support was required postoperatively. Associations between preoperative and intraoperative variables and prolonged hypotension were evaluated. RESULTS: Two hundred and one (48.6%) patients had postoperative hypotension that required vasopressor support with a median duration of 20 h. Multivariable analysis demonstrated that increased 24-h urinary norepinephrine (NE) levels (odds ratio [OR] = 1.091, 95% confidence interval [CI]: 1.052-1.132, p < .001), longer operative time (OR = 1.008, CI: 1.004-1.011, p < .001) and lower preoperative phenoxybenzamine dose (OR = 0.336, CI: 0.150-0.753, p = .008) were predictors of prolonged hypotension. Moreover, operative time, body mass index, 24-h urinary level of NE and preoperative phenoxybenzamine dose were significantly correlated with the duration of postoperative vasopressor support. CONCLUSIONS: Increased urine NE level, longer operative time and lower preoperative phenoxybenzamine dose were predictors of prolonged hypotension requiring vasopressor support. Clinicians can identify these factors to manage their patients better and prevent severe complications.

Management and outcome of metastatic pheochromocytomas/paragangliomas: an overview.

BACKGROUND: Metastatic pheochromocytomas and paragangliomas (PPGLs) occur in about 5-26% of cases and are characterized by a heterogeneous prognosis. Metastases can be synchronous at the initial diagnosis, but they can occur also many years after surgery for the primary tumor. To date, the treatment of patients affected by metastatic PPGLs represents a clinical challenge because of the lack of guidelines. AIM: The aim of this article is to review the available management options and their impact on the outcomes of patients with metastatic PPGLs. RESULTS: Generally, treatments are not curative. Surgery, when possible, can be used to reduce hormonal symptoms and cardiovascular morbidity. Chemotherapy plays a role in patients with high burden tumor and rapid disease progression. Tyrosine kinases inhibitors (TKIs) might be considered for their ability to block the angiogenesis and cell growth. Radiation therapy and interventional radiology techniques can help in the management of local metastases to control symptoms and avoid tumor progression. On the other hand, peptide receptor radionuclide therapy (PRRT), using 90Y or 177Lu-DOTATATE, could be a promising therapy. In addition, high specific 131I-MIBG was approved by the Food and Drug Administration (FDA) in the US for the treatment of patients affected by metastatic and unresectable 131I-MIBG positive PPGLs. Considering the different pathways involved in the pathogenesis of PPGLs, several target therapies have been proposed and are under evaluation in clinical trials. CONCLUSIONS: The choice of the appropriate treatment should be based on multidisciplinary and personalized approach taking into account the rarity and the variability of these tumors.

Clinical features and outcomes of metastatic pheochromocytoma treated by cytotoxic chemotherapy.

Cytotoxic chemotherapy, including cyclophosphamide, vincristine, and dacarbazine (CVD) therapy, is widely used to treat metastatic pheochromocytoma and paraganglioma. Because these diseases are rare, studies are needed to establish treatment strategies. This was a single-center and retrospective study to analyze the efficacy of chemotherapy for patients with metastatic pheochromocytoma and paraganglioma diagnosed in 1983-2020. Clinical characteristics, tumor volume response, biochemical response based on catecholamine level, overall survival, and progression-free survival were evaluated. Patients with a complete response or partial response in tumor volume or catecholamine level were classified as responders. Sixteen patients were administered chemotherapy for a median of 16.5 cycles (interquartile range, 10-42). The tumor volume response was classified as follows: partial response (N = 4), stable disease (N = 9), and progressive disease (N = 3) (disease control rate = 81%). The biochemical responses were as follows: complete response (N = 2), partial response (N = 5), no change (N = 3), and progressive disease (N = 1) (disease control rate = 91%). The 5-year survival rate was 50% (95% confidence interval [CI], 21-74%) and median overall survival was 4.4 years (95% CI, 2.4 years-not reached). Overall survival and progression-free survival between responders and nonresponders were not statistically different. One patient developed myelodysplastic syndrome during CVD therapy. In conclusion, chemotherapy achieved disease control among more than half of patients, although survival did not differ between responders and nonresponders. Further fundamental research and prospective trials are needed to analyze the efficacy of CVD therapy.

A phase 2 trial of sunitinib in patients with progressive paraganglioma or pheochromocytoma: the SNIPP trial.

BACKGROUND: Pheochromocytoma (PCC) and paraganglioma (PGL) are uncommon neoplasms with high morbidity in advanced stages. Effective systemic treatments are limited. METHODS: A multisite phase 2 trial evaluated sunitinib in patients with progressive PCC/PGL. Patients received 50 mg orally for 4-6 weeks. RESULTS: Between May 2009 and May 2016, 25 patients were enroled. The median age was 50 years and 56% were male. Three patients (12%) received prior chemotherapy and 16 (64%) prior surgery. The DCR was 83% (95% CI: 61-95%) and median PFS 13.4 (95% CI: 5.3-24.6) months. Of 23 evaluable patients, 3 (13%) with germline mutations (SDHA, SDHB, RET) achieved a PR. The patient with mutated RET and MEN2A remains on treatment after 64 cycles. The median time on treatment was 12.4 (1-88.0) months. Grade 3 or 4 toxicities were as expected and manageable; fatigue (16%) and thrombocytopenia (16%) were most common. One patient with grade 3 hypertension and 2 with grade 3 cardiac events discontinued treatment. CONCLUSION: Although the primary endpoint of disease control was met, the overall response rate of sunitinib was low in unselected patients with progressive PCC/PGL. Patients with germline variants in RET or in the subunits of SDH may derive greatest benefit.

Association Between Urinary Catecholamine Excretion and Urine Volume.

Several confounders must be considered in the evaluation of urinary catecholamine excretion. However, literature is contradictory about potential confounders. The aim of the present study was to assess correlations between catecholamine excretion and anthropometric or clinical parameters with special attention to urine volume. A total of 967 24-h urinary catecholamine measurements were performed in 593 patients for diagnostic purposes. The indication for urine examination was suspicion of secondary hypertension, phaeochromocytoma, or paraganglioma. From the patients examined, 57% were females and 43% were males. The patients' age ranged between 15 and 87 years with a median [Q1; Q3] of 51 [39; 62] years. Seventy-eight percent of the patients suffered from hypertension. Seventy percent of patients took one or more antihypertensive drugs. The most commonly used drugs were ACE inhibitors (43%), while α-blockers (15%) were the least used drugs. Urinary excretion was between 500 and 11 950 ml/24 h with a median of 2200 [1600; 2685] ml/24 h. The median body mass index (BMI) was 26.7 [24.0; 30.4] kg/m2. The excretion of all catecholamines was greater in men than in women (all p<0.0001). Epinephrine (p=0.0026), dopamine (p<0.0001), and metanephrine (p=0.0106) excretion decreased with age. BMI was associated with urinary excretion of dopamine (p<0.0001), norepinephrine (p=0.0026), normetanephrine (p<0.0001), and homovanillylmandelic acid (HVMA; p=0.0251). Urine volume correlated with urinary dopamine (p=0.0127), metanephrine (p<0.0001), normetanephrine (p=0.0070), and HVMA (p<0.0028) excretion. In addition to the established associations between urinary catecholamine excretion and age, gender, and BMI in the present study, urinary catecholamine excretion correlated also with urine volume.

Correlation between urinary fractionated metanephrines in 24-hour and spot urine samples for evaluating the therapeutic effect of metyrosine: a subanalysis of a multicenter, open-label phase I/II study.

We recently conducted an open-label phase I/II study to evaluate the efficacy and safety of preoperative and chronic treatment with metyrosine (an inhibitor of catecholamine synthesis) in pheochromocytoma/paraganglioma (PPGL) in Japan. We compared creatinine-corrected metanephrine fractions in spot urine and 24-hour urine samples (the current standard for the screening and diagnosis of PPGLs) from 16 patients to assess the therapeutic effect of metyrosine. Percent changes from baseline in urinary metanephrine (uMN) or normetanephrine (uNMN) were compared between spot and 24-hour urine samples. Mean percent changes in uMN or uNMN in spot and 24-hour urine were -26.36% and -29.27%, respectively. The difference in the percent change from baseline between uMN or uNMN in spot and 24-hour urine was small (-2.90%). The correlation coefficient was 0.87 for percent changes from baseline between uMN or uNMN measured in spot and 24-hour urine. The area under the receiver operator characteristic (ROC) curve of uMN or uNMN measured in spot urine vs. 24-hour urine (reference standard) to assess the efficacy of metyrosine treatment was 0.93. Correlations and ROCs between 24-hour urinary vanillylmandelic acid, adrenaline, and noradrenaline and 24-hour uMN or uNMN were similar to those between spot uMN or uNMN and 24-hour uMN or uNMN. No large difference was observed between spot and 24-hour urine for the assessment of metyrosine treatment by quantifying uMN or uNMN in Japanese patients with PPGLs. These results suggest that spot urine samples may be useful in assessing the therapeutic effect of metyrosine.

Paragangliomas arise through an autonomous vasculo-angio-neurogenic program inhibited by imatinib.

Tumours can be viewed as aberrant tissues or organs sustained by tumorigenic stem-like cells that engage into dysregulated histo/organogenetic processes. Paragangliomas, prototypical organoid tumours constituted by dysmorphic variants of the vascular and neural tissues found in normal paraganglia, provide a model to test this hypothesis. To understand the origin of paragangliomas, we built a biobank comprising 77 cases, 18 primary cultures, 4 derived cell lines, 80 patient-derived xenografts and 11 cell-derived xenografts. We comparatively investigated these unique complementary materials using morphofunctional, ultrastructural and flow cytometric assays accompanied by microRNA studies. We found that paragangliomas contain stem-like cells with hybrid mesenchymal/vasculoneural phenotype, stabilized and expanded in the derived cultures. The viability and growth of such cultures depended on the downregulation of the miR-200 and miR-34 families, which allowed high PDGFRA and ZEB1 protein expression levels. Both tumour tissue- and cell culture-derived xenografts recapitulated the vasculoneural paraganglioma structure and arose from mesenchymal-like cells through a fixed developmental sequence. First, vasculoangiogenesis organized the microenvironment, building a perivascular niche which in turn supported neurogenesis. Neuroepithelial differentiation was associated with severe mitochondrial dysfunction, not present in cultured paraganglioma cells, but acquired in vivo during xenograft formation. Vasculogenesis was the Achilles' heel of xenograft development. In fact, imatinib, that targets endothelial-mural signalling, blocked paraganglioma xenograft formation (11 xenografts from 12 cell transplants in the control group versus 2 out of 10 in the treated group, P = 0.0015). Overall our key results were unaffected by the SDHx gene carrier status of the patient, characterized for 70 out of 77 cases. In conclusion, we explain the biphasic vasculoneural structure of paragangliomas and identify an early and pharmacologically actionable phase of paraganglioma organization.

Continued Tumor Reduction of Metastatic Pheochromocytoma/Paraganglioma Harboring Succinate Dehydrogenase Subunit B Mutations with Cyclical Chemotherapy.

Patients harboring germline mutations in the succinate dehydrogenase complex subunit B (SDHB) gene present with pheochromocytomas and paragangliomas (PPGL) that are more likely malignant and clinically aggressive. The combination chemotherapy cyclophosphamide, vincristine, and dacarbazine (CVD) was retrospectively evaluated in patients with SDHB-associated metastatic PPGL.Query Twelve metastatic PPGL patients harboring SDHB mutations/polymorphisms with undetectable SDHB immunostaining were treated with CVD. CVD therapy consisted of 750 mg/m2 cyclophosphamide with 1.4 mg/m2 vincristine on day 1 and 600 mg/m2 dacarbazine on days 1 and 2, every 21-28 days. Treatment outcome was determined by RECIST criteria as well as determination of response duration and progression-free and overall survivals. A median of 20.5 cycles (range 4-41) was administered. All patients had tumor reduction (12-100% by RECIST). Complete response was seen in two patients, while partial response was observed in 8. The median number of cycles to response was 5.5. Median duration of response was 478 days, with progression-free and overall survivals of 930 and 1190 days, respectively. Serial [18F]-fluorodeoxyglucose positron emission tomography and computed tomography imaging demonstrated continued incremental reduction in maximal standardized uptake values (SUVmax) values in 26/30 lesions. During treatment administration, the median SUV decreased from > 25 to < 6, indicating the efficacy of chemotherapy over a prolonged period of time. Prolonged therapy results in continued incremental tumor reduction, and is consistent with persistent drug sensitivity. CVD chemotherapy is recommended to be considered part of the initial management in patients with metastatic SDHB-related PPGL.

Temozolomide treatment of a malignant pheochromocytoma and an unresectable MAX-related paraganglioma.

Pheochromocytomas (PCCs) and paragangliomas (PGLs) are neuroendocrine tumors with a strong genetic background. The mainstay of treatment for PCC/PGLs is surgery. However, for unresectable lesions, no curative treatment is currently available. Temozolomide (TMZ) has been shown to determine radiological and biochemical response in malignant PCC/PGLs. We report two cases of PCC/PGLs treated with TMZ. Case 1 is a 51-year-old man with local and distant recurrence (liver and bone metastases) of right adrenal PCC. Case 2 is a 54-year-old woman with a PCC/PGL syndrome caused by a mutation in MAX gene (c.171+1G>A), operated on for bilateral adrenal PCC and presenting with a large unresectable abdominal PGL. Both patients presented hypertension due to catecholamine hypersecretion. TMZ determined radiological response according to RECIST criteria, reduction of urinary catecholamine levels, and controlled hypertension in both patients. Furthermore, the current study demonstrates, for the first time, that MAX-related PGLs are responsive to TMZ.

Efficacy and safety of metyrosine in pheochromocytoma/paraganglioma: a multi-center trial in Japan.

To assess the efficacy, safety, and pharmacokinetics of metyrosine (an inhibitor of catecholamine synthesis) in patients with pheochromocytoma/paraganglioma (PPGL), we conducted a prospective, multi-center, open-label study at 11 sites in Japan. We recruited PPGL patients aged ≥12 years requiring preoperative or chronic treatment, receiving α-blocker treatment, having baseline urinary metanephrine (uMN) or normetanephrine (uNMN) levels ≥3 times the upper limit of normal values, and having symptoms associated with excess catecholamine. Metyrosine treatment was started at 500 mg/day and modified according to dose-adjustment criteria up to 4,000 mg/day. The main outcome measure was the proportion of patients who achieved at least 50% reduction in uMN or uNMN levels from baseline. Sixteen patients (11 males/5 females) aged 12-86 years participated. After 12 weeks of treatment and at the last evaluation of efficacy, the primary endpoint was achieved in 31.3% of all patients, including 66.7% of those under preoperative treatment and 23.1% of those under chronic treatment. Sedation, anemia, and death were reported in 1 patient each as serious adverse drug reactions during the 24-week treatment. Metyrosine was shown to be tolerated and to relieve symptoms by reducing excess catecholamine in PPGL patients under both preoperative and chronic treatment.

Preoperative alpha-blockade in phaeochromocytoma and paraganglioma: is it always necessary?

Resection of phaeochromocytoma and paraganglioma (PPGL) is traditionally preceded by alpha-blockade to prevent complications of haemodynamic instability intraoperatively. While there is general agreement on preoperative alpha-blockade for classic PPGLs presenting with hypertension, it is less clear whether alpha-blockade is necessary in predominantly dopamine-secreting tumours, normotensive PPGLs, as well as tumours that appear to be biochemically 'silent'. Preoperative management of these 'atypical' PPGLs is challenging and the treatment approach must be individualized, carefully weighing the risk of intraoperative hypertension against the possibility of orthostatic and prolonged postoperative hypotension. Consideration of antihypertensive medication pharmacology in the light of catecholamine physiology and PPGL secretory profile will facilitate the formulation of individualized preoperative preparatory strategies.

Acute myeloid leukemia therapy elicits durable complete response in chemoradio-resistant metastatic paraganglioma.

Few effective therapeutic options exist for patients with metastatic paraganglioma (PGL). We report the case of a 16-year-old male who developed acute myeloid leukemia (AML) 30 months following the treatment for metastatic PGL. PGL had been refractory to 131 I-meta-iodobenzylguanidine and temozolomide therapy. However, there was a major reduction in primary tumor allowing its gross total resection, and complete resolution of metastatic disease following AML-directed therapy that included daunorubicin, cytarabine, and etoposide. He remains in remission for both AML and PGL, 48 months post AML chemotherapy. Alternative chemotherapeutic agents should be considered for metastatic PGL resistant to conventional therapy.

Treatment for Malignant Pheochromocytomas and Paragangliomas: 5 Years of Progress.

PURPOSE OF REVIEW: The purpose of this manuscript is to review the progress in the field of therapeutics for malignant pheochromocytomas and sympathetic paraganglioma (MPPG) over the past 5 years. RECENT FINDINGS: The manuscript will describe the clinical predictors of survivorship and their influence on the first TNM staging classification for pheochromocytomas and sympathetic paragangliomas, the treatment of hormonal complications, and the rationale that supports the resection of the primary tumor and metastases in patients with otherwise incurable disease. Therapeutic options for patients with bone metastasis to the spine will be presented. The manuscript will also review chemotherapy and propose a maintenance regimen with dacarbazine for patients initially treated with cyclophosphamide, vincristine, and dacarbazine. Finally, the manuscript will review preliminary results of several phase 2 clinical trials of novel radiopharmaceutical agents and tyrosine kinase inhibitors. MPPGs are very rare neuroendocrine tumors. MPPGs are usually characterized by a large tumor burden, excessive secretion of catecholamines, and decreased overall survival. Recent discoveries have enhanced our knowledge of the pathogenesis and phenotypes of MPPG. This knowledge is leading to a better understanding of the indications and limitations of the currently available localized and systemic therapies as well as the development of phase 2 clinical trials for novel medications.