Central Nervous System Hemangioblastomas Research Articles

Somatostatin receptor 2A expression in von Hippel-Lindau-related hemangioblastomas.

Central nervous system hemangioblastomas are the most prevalent manifestation of von Hippel-Lindau (VHL) disease and remain the main cause of mortality. Surgical resection is the primary treatment strategy, but is not always possible, and should be used as restrictively as possible. There is an unmet need for less invasive treatment strategies, such as targeted therapy. Expression of somatostatin receptor 2A (SSTR2A) in VHL-related hemangioblastomas has been described earlier, but the extent of expression in a larger population has yet to be determined. The authors hypothesize that a substantial subset of VHL-related hemangioblastomas show SSTR2A expression, which may serve as a potential new treatment target. Patients who were surgically treated for a VHL-related hemangioblastoma from 1990 until 2021 at the UMC Utrecht were included. Clinical data was derived from a clinical database. Tissue samples were histopathologically examined with use of hematoxylin and eosin staining, and immunohistochemical analysis of SSTR2A expression was performed. Forty-three tissue samples were obtained from 26 patients. Nine showed strong positivity for SSTR2A expression, whereas 13 showed moderate and 15 sparse expression. Three samples showed no expression of SSTR2A. The distribution showed right-skewedness favoring a strong expression. SSTR2A expression colocalized with endothelial markers and not with stromal cells. Additionally, within-patient variability for SSTR2A expression was described in 14 patients. SSTR2A is expressed in varying degrees in the majority of VHL-related hemangioblastomas. Future treatment with somatostatin analogues or even peptide receptor radionuclide treatment may be considered for SSTR2A-positive cases.

39 Safety profile of belzutifan monotherapy in patients with renal cell carcinoma: A pooled analysis of 4 clinical trials

Abstract Background The first-in-class hypoxia-inducible factor-2α inhibitor, belzutifan, is indicated in the United States for the treatment of certain patients with von Hippel-Lindau (VHL) disease–associated renal cell carcinoma (RCC), central nervous system hemangioblastomas, or pancreatic neuroendocrine tumors not requiring immediate surgery and for patients with advanced RCC previously treated with a PD-(L)1 inhibitor and a vascular endothelial growth factor tyrosine kinase inhibitor. Due to its unique mechanism of action, belzutifan has a distinct safety profile. We characterized the safety profile of belzutifan monotherapy in a post hoc pooled analysis of patients with previously treated advanced clear cell RCC in the phase 1 LITESPARK-001 (NCT02974738), phase 3 LITESPARK-005 (NCT04195750), and phase 2 LITESPARK-013 (NCT04489771) studies and patients with RCC associated with VHL disease in the phase 2 LITESPARK-004 study (NCT03401788). Methods All patients who received ≥1 dose of belzutifan 120 mg orally once daily across the 4 studies were included. Severity of adverse events (AEs) were graded per the National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.03 or 5.0, and were descriptively summarized. Results A total of 576 patients were included (n = 58 [including 3 patients with advanced solid tumors other than RCC], LITESPARK-001; n = 381, LITESPARK-005; n = 76, LITESPARK-013; and n = 61, LITESPARK-004). Overall, 572 patients (99.3%) had ≥1 all-cause AE and 355 patients (61.6%) had ≥1 grade 3-5 AE. AEs led to dose modification (reduction, interruption, or discontinuation) in 288 patients (50.0%), although treatment discontinuation for AEs occurred in 37 patients (6.4%). The most common all-grade AEs were anemia (including patients with decreased hemoglobin; n = 485 [84.2%]; grade 3 or 4, n = 166 [28.8%]), fatigue (n = 246 [42.7%]; grade 3, n = 16 [2.8%]), nausea (n = 139 [24.1%]; grade 3, n = 5 [0.9%]), and dyspnea (n = 123 [21.4%]; grade 3 or 4, n = 10 [1.7%]). Hypoxia was reported in 94 patients (16.3%); grade 3 or 4 hypoxia occurred in 57 patients (9.9%). Summary and time to first onset of adverse drug reactions (AEs considered associated with belzutifan), including anemia and hypoxia, are reported in the table. Among 485 patients with anemia or decreased hemoglobin, 111 (22.9%) were treated with erythropoiesis-stimulating agent (ESA) only, 85 (17.5%) were treated with blood transfusions only, and 62 (12.8%) were treated with ESA and blood transfusions. Among 94 patients with hypoxia, 66 (70.2%) were treated with oxygen therapy. Treatment-related AEs occurred in 526 patients (91.3%) and 217 (37.7%) experienced a grade 3-5 treatment-related AE. One grade 5 adverse event (multiple organ dysfunction syndrome) was considered related to treatment. Conclusions To date, this is the largest pooled safety dataset for belzutifan monotherapy in patients with RCC. The results provide an in-depth characterization of the safety profile for belzutifan and the associated AE management strategies.

Trigeminal nerve hemangioblastoma in the setting of undiagnosed von Hippel-Lindau disease: illustrative case.

Von Hippel-Lindau disease (VHL) is an autosomal dominant tumor predisposition syndrome caused by mutations in the VHL gene. Patients with VHL are predisposed to developing numerous neoplasms, including central nervous system hemangioblastomas that typically arise within the cerebellum, brainstem, or spinal cord. The authors present the unusual case of a 69-year-old patient with a hemangioblastoma of the trigeminal nerve as his initial presentation of VHL. A 69-year-old male presented with progressive right-sided V3 paresthesias, gait disturbance, and diplopia. Magnetic resonance imaging demonstrated an enhancing 0.5-cm nodule within the right trigeminal nerve and an associated peritumoral cyst exerting mass effect on the cerebral peduncle. Neural axis imaging demonstrated pia-based enhancing lesions concerning for multiple spinal hemangioblastomas. The patient underwent an uncomplicated retrosigmoid craniotomy for trigeminal nerve hemangioblastoma resection. The patient had postoperative improvement in his gait, diplopia, and facial paresthesias. Genetic testing revealed that the patient was heterozygous for a pathological mutation in the VHL gene. Hemangioblastomas in adults over 50 years of age should prompt a workup for VHL. Recognizing that cranial nerves are a possible site of hemangioblastoma occurrence is important for neurosurgeons and radiologists alike. Resection of cranial nerve hemangioblastomas is technically challenging but can lead to symptom improvement for patients. https://thejns.org/doi/10.3171/CASE24149.

Real-world monitoring and treatment patterns in von Hippel-Lindau (VHL) disease-associated central nervous system hemangioblastomas (CNS-Hb).

2086 Background: VHL disease is an inherited tumor syndrome that causes multiple benign and malignant tumors to develop; CNS-Hb is often the first VHL disease manifestation, occurring in 70-80% of patients with VHL. Patients often need many tumor treatments to manage the disease. This study evaluated disease monitoring and treatment patterns among patients with VHL-CNS-Hb. Methods: Using an algorithm based on VHL manifestations, patients with VHL were identified from Optum’s de-identified Clinformatics Data Mart Database. Patients with a CNS-Hb diagnosis were then selected. Treatment patterns were assessed among patients with VHL after their initial diagnosis of CNS-Hb. Incidence rates (IR) of the following treatments for managing CNS-Hb or other VHL-associated tumors were assessed: surgery for removal of VHL-associated tumors, renal ablation, radiotherapy, targeted therapy for RCC, and retinal laser therapy. Rates for tumor treatments were reported as events per 10-person years. Generalized linear models estimated IRs of analgesic use, VHL disease monitoring procedures, and visits to VHL-related medical specialists in the patient and control cohorts, adjusting for age, sex, the number of outpatient visits at baseline, and health plan type. Results: 220 patients with VHL-CNS-Hb were identified. Reflecting the multifaceted nature of VHL disease, the tumor treatments with the highest unadjusted IRs during the study period among these patients were targeted RCC therapies (2.15 per 10-person years), surgical removal of cerebellar and spinal hemangioblastomas (0.52 per 10-person years), and radiotherapy (0.42 per 10-person years). The tablecontains estimated adjusted IRs and IRRs for the use of select analgesics, monitoring procedures, and medical specialist visits for the VHL-CNS-Hb and comparator cohorts. Conclusions: VHL-CNS-Hb presents a multifaceted burden, involving treatments for various VHL-related tumors. Patients with VHL-CNS-Hb use more analgesics, undergo frequent monitoring, and have increased specialist visits compared with the control group. Successful tumor control holds the potential to reduce morbidity and long-term medical management associated with the disease. [Table: see text]

Belzutifan in Individuals with von Hippel-Lindau Retinal Hemangioblastomas: Institutional Experience and Review of the Literature

Introduction: The systemic HIF-2 alpha inhibitor, belzutifan, has been approved for use in patients with von Hippel-Lindau disease (VHL)-associated renal cell carcinoma, central nervous system (CNS) hemangioblastomas, and pancreatic neuroendocrine tumors. This drug has also shown promise in controlling VHL retinal hemangioblastomas (RHs), but little work has been published on the use of the drug in this setting. Methods: We conducted a retrospective review of patients with VHL-associated RHs followed by the retina service at our institution who were treated with systemic belzutifan. Patient age, gender, genotype, presence of systemic tumors, indication for the drug, initial dose, adjusted dose, side effects, and tumor response were recorded. We also conducted a literature search for all manuscripts describing the effect of belzutifan on VHL-associated ocular tumors. Results: We identified 12 eyes of 7 patients with VHL-associated ocular tumors who were treated with belzutifan at our institution. Of these, 5 eyes of 3 patients had progressing ocular tumors when belzutifan was started. Of the 7 total patients, 2 were treated for renal cell carcinoma, 2 for CNS hemangioblastomas, 2 for RHs, and one for pancreatic neuroendocrine tumors. Initial dose was 120 mg PO daily in 6 patients and 80 mg PO daily in 1 patient. The dose was reduced in all but 1 patient due to side effects. The ocular tumors were controlled in all patients with an average follow-up of 13 months (range 4–24 months). Literature review identified 7 manuscripts that described belzutifan-mediated control of ocular tumors in patients with VHL-associated RHs in 21 patients. Conclusion: The drug belzutifan shows great promise for controlling RHs and preventing vision loss in patients with VHL. Further work needs to address the optimal dose, role of the drug as a neoadjuvant therapy, and long-term efficacy and tolerability of the drug in a larger cohort of patients with ocular tumors.

Screening and surveillance recommendations for central nervous system hemangioblastomas in pediatric patients with Von Hippel-Lindau disease

PurposeVon Hippel-Lindau (VHL) disease is an autosomal-dominantly inherited tumor predisposition syndrome. One of the most common tumors are central nervous system (CNS) hemangioblastomas. Recommendations on the initiation and continuation of the screening and surveillance program for CNS tumors in pediatric VHL patients are based on small case series and thus low evidence level. To derive more robust screening recommendations, we report on the largest monocentric pediatric cohort of VHL patients.MethodsWe performed a retrospective analysis on a pediatric cohort of 99 VHL patients consulted at our VHL center from 1992 to 2023. Clinical, surgical, genetic, and imaging data were collected and statistically analyzed.Results42 patients (50% male) developed CNS hemangioblastomas, of whom 18 patients (56% male) underwent hemangioblastoma surgery (mean age at first surgery: 14.9 ± 1.9 years; range 10.2–17). The first asymptomatic patient was operated on at the age of 13.2 years due to tumor progress. Truncating VHL mutation carriers had a significantly higher manifestation rate (HR = 3.7, 95% CI: 1.9–7.4, p < 0.0001) and surgery rate (HR = 3.3, 95% CI: 1.2–8.9, p = 0.02) compared with missense mutation carriers.ConclusionWe recommend starting MRI imaging at the age of 12 years with examination intervals every (1-) 2 years depending on CNS involvement. Special attention should be paid to patients with truncating variants. Affected families should be educated regularly on potential tumor-associated symptoms to enable timely MRI imaging and eventually intervention, as CNS hemangioblastoma may develop before screening begins.German clinical trials Register registration numberDRKS00029553, date of registration 08/16/2022, retrospectively registered.

Abstract CT221: Belzutifan, a hypoxia-inducible factor-2α (HIF-2α) inhibitor, for von Hippel-Lindau (VHL) disease-associated neoplasms: Long-term results of the phase 2 LITESPARK-004 study

Abstract Introduction: Belzutifan is a first-in-class HIF-2α inhibitor approved for patients (pts) with VHL disease-associated renal cell carcinoma (RCC), central nervous system (CNS) hemangioblastomas (HB), or pancreatic neuroendocrine tumors (pNET) not requiring immediate surgery based on initial results from the phase 2 LITESPARK-004 study (NCT03401788). We present results from pts with more than 4 years of follow-up from LITESPARK-004. Methods: Adults with germline VHL alteration, ≥1 measurable nonmetastatic RCC tumor, no RCC tumor &amp;gt;3 cm requiring immediate surgery, and no prior systemic anticancer therapy received oral belzutifan 120 mg once daily until disease progression, unacceptable toxicity, or withdrawal. The primary end point was objective response rate (ORR) in VHL-associated RCC per RECIST v1.1 by independent review. Secondary end points included ORR in CNS HB and pNET; duration of response (DOR), time to response (TTR), progression-free survival (PFS), and time to surgery (TTS) in RCC, CNS HB, and pNET; and safety. Results: As of April 3, 2023, 36 of 61 pts (59%) were continuing treatment. Median follow-up was 49.9 mo (range, 48.2-58.1). Efficacy data are shown in the table. In the 4 years preceding belzutifan treatment, 46 pts (75%) underwent a total of 86 VHL-related tumor reduction procedures (surgery or radiation therapy). Since starting belzutifan, 16 pts (26%) underwent 18 tumor reduction procedures (RCC, n = 13; CNS HB, n = 3; retinal HB, n = 2). Safety profile remained unchanged with long-term follow-up. Conclusions: With a median follow-up of more than 4 years, belzutifan continues to demonstrate clinically meaningful ORR and durable responses in VHL-associated RCC, CNS HBs, and pNET. Fewer tumor reduction procedures were observed after pts started belzutifan treatment. These results support belzutifan as a standard of care for this pt population. Citation Format: Ramaprasad Srinivasan, Othon Iliopoulos, Kathryn E. Beckermann, Vivek Narayan, Benjamin L. Maughan, Stephane Oudard, Tobias Else, Jodi K. Maranchie, Ane B. Iversen, Jerry Cornell, Rodolfo F. Perini, Yanfang Liu, W. Marston Linehan, Eric Jonasch. Belzutifan, a hypoxia-inducible factor-2α (HIF-2α) inhibitor, for von Hippel-Lindau (VHL) disease-associated neoplasms: Long-term results of the phase 2 LITESPARK-004 study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT221.

Epidemiology and economic burden of Von Hippel-Lindau Disease-associated central nervous system hemangioblastomas and pancreatic neuroendocrine tumors in the United States

BackgroundTo date, real-world evidence around the clinical and economic burden related to von Hippel-Lindau (VHL) disease is limited. Therefore, this study characterized the prevalence, healthcare resource utilization (HRU), and economic burden of von Hippel-Lindau–associated central nervous system hemangioblastoma (VHL-CNS-Hb) and pancreatic neuroendocrine tumors (VHL-pNET) in the United States (US).MethodsPatients with VHL-CNS-Hb or VHL-pNET were identified from Optum’s de-identified Clinformatics® Data Mart Database (2007–2020) and matched 1:5 to control patients without VHL disease or CNS-Hb/pNET. Prevalence rates of VHL-CNS-Hb and VHL-pNET (standardized by age and sex) in 2019 were estimated. HRU and healthcare costs (2020 US dollars) were compared between the VHL-CNS-Hb/VHL-pNET and control cohorts.ResultsIn 2019, US prevalence rates of VHL-CNS-Hb and VHL-pNET were estimated to be 1.12 cases per 100,000 (3,678 patients) and 0.12 cases per 100,000 (389 patients), respectively. Patients with VHL-CNS-Hb (N = 220) had more inpatient, outpatient, and emergency department visits and $49,645 higher annual healthcare costs than controls (N = 1,100). Patients with VHL-pNET (N = 20) had more inpatient and outpatient visits and $56,580 higher annual healthcare costs than controls (N = 100). Costs associated with surgical removal of CNS-Hb and pNET were particularly high.ConclusionsIn this retrospective, claims-based study, both VHL-CNS-Hb and VHL-pNET were associated with substantial HRU and healthcare costs, particularly tumor reduction surgery–related costs. These findings provide important insight for healthcare payers regarding the expected real-world costs that enrollees with VHL-CNS-Hb and VHL-pNET may incur over the course of their disease.

Spinal cord hemangioblastomas in von Hippel-Lindau disease.

von Hippel-Lindau disease (VHL) is an autosomal dominant familial neoplasia syndrome. The most common manifestation of VHL is central nervous system hemangioblastomas. VHL patients will often develop multiple hemangioblastomas along their craniospinal axis over their lifetime. Spinal cord hemangioblastomas account for nearly half of all nervous system hemangioblastomas in VHL. The authors conducted a literature review and summation of available articles on spinal cord hemangioblastomas associated with VHL. The embryological origins, epidemiology, natural history, surgical outcomes, nonsurgical treatments, and future directions in spinal cord hemangioblastomas are discussed. Hemangioblastomas in VHL are optimally managed with a multidisciplinary approach that includes surgical resection of symptomatic lesions. Novel treatments are gaining traction, but must be studied further for efficacy and safety.

Belzutifan (Welireg)

&#x0D; CADTH reimbursement reviews are comprehensive assessments of the clinical effectiveness and cost-effectiveness, as well as patient and clinician perspectives, of a drug or drug class.&#x0D; The assessments inform non-binding recommendations that help guide the reimbursement decisions of Canada's federal, provincial, and territorial governments, with the exception of Quebec.&#x0D; This review assesses Belzutifan (Welireg), 40 mg, tablets, oral.&#x0D; Indication: For treatment of adult patients with von Hippel-Lindau disease who require therapy for an associated nonmetastatic renal cell carcinoma, central nervous system hemangioblastoma, or nonmetastatic pancreatic neuroendocrine tumour not requiring immediate surgery.&#x0D;

The outcome of central nervous system hemangioblastomas in Von Hippel-Lindau (VHL) disease treated with belzutifan: a single-institution retrospective experience.

Belzutifan is a Hypoxia Inducible Factor 2-alpha inhibitor approved in 2021 by the FDA for the treatment of renal cell carcinoma (RCC) in patients with Von-Hippel Landau (VHL) disease. These patients can also present with central nervous system (CNS) hemangioblastomas (HBs). We aim to study the effectiveness and adverse effects of belzutifan for CNS HBs, by reporting our preliminary institutional experience. We present a series of VHL patients with CNS HBs undergoing treatment with belzutifan for RCC. All the included patients met the RECIST inclusion criteria. The clinical and radiological outcome measures included: Objective response rate (ORR), time-to-response (TTR), adverse events (AE), and patient response. Patient response was classified as partial response (PR), complete response (CR), progressive disease (PD), or stable disease (SD). Seven patients with 25 HBs were included in our study. A belzutifan dose of 120mg/day PO was administered for a median of 13 months (range 10-17). Median follow up time was 15 months (range 10-24). An ORR of 71% was observed. The median TTR was 5 months (range: 1-10). None of the patients showed CR, while 5 patients (71.4%) showed PR and 2 (28.5%) showed SD. Among patients with SD the maximum tumor response was 20% [increase/decrease] of the lesion diameter. All the patients experienced decreased hemoglobin concentration, fatigue, and dizziness. None of the patients experienced severe anemia (grade 3-4 CTCAE). Belzutifan appears to be an effective and safe treatment for CNS hemangioblastoma in VHL patients. Further clinical trials to assess the long-term effectiveness of the medication are required.

Pre-Induction Scalp Block in a Patient of von HippelLindau Disease: Promising Use in High-Risk Neurosurgical Procedures

Multiple modalities have been tried for post-craniotomy pain relief, but controversy exists as to the optimal approach. Pre-induction scalp block is a promising technique in high-risk neurosurgical procedures, which reduces the haemodynamic response to skull pin insertion and craniotomy incision, and affords post-operative analgesia. von hippel-lindau (VHL) disease is a rare autosomal dominant disorder with multi-system involvement and various visceral manifestations, the most common of these-being cerebellar hemangioblastoma. Other anomalies include pancreatic-renal cysts, erythrocytosis, hypernephroma, pheochromocytoma and retinal capillary hemangioblastoma. Central nervous system (CNS) hemangioblastomas are often an early manifestation of the disease, and are typically seen in the second decade of life. The majority of hemangioblastomas occur in the cerebellum followed by the spinal cord and brain stem. They are benign vascular tumours but can cause neurological symptoms secondary to pressure or haemorrhage. We hereby present a case of previously diagnosed VHL with recurrent cerebellar hemangioblastoma scheduled for neurosurgical tumour excision and the beneficial use of a pre-induction scalp block to compliment anaesthesia for the patient.

Belzutifan (Welireg)

&#x0D; CADTH recommends that Welireg should be reimbursed by public drug plans for the treatment of adult patients with von Hippel-Lindau (VHL) disease who require therapy for associated nonmetastatic renal cell carcinoma (RCC), central nervous system (CNS) hemangioblastomas, or nonmetastatic pancreatic neuroendocrine tumours (pNET), not requiring immediate surgery if certain conditions are met.&#x0D; Welireg should only be covered to treat adult patients with VHL disease who require therapy for associated nonmetastatic RCC, CNS hemangioblastomas, or nonmetastatic pNET, not requiring immediate surgery. Patients receiving Welireg should be in relatively good health.&#x0D; Welireg should only be reimbursed if it is prescribed by specialists with expertise in VHL disease-associated tumours and if the cost of Welireg is reduced. Welireg should not be used in combination with other anti-tumour drugs.&#x0D;

Population Pharmacokinetic Analyses for Belzutifan to Inform Dosing Considerations and Labeling.

Belzutifan (Welireg, Merck & Co, Inc.) is an oral, potent inhibitor of hypoxia-inducible factor (HIF) 2α, approved for the treatment of certain patients with von Hippel-Lindau (VHL) disease-associated renal cell carcinoma (RCC), central nervous system hemangioblastomas, and pancreatic neuroendocrine tumors (pNET). It is primarily metabolized by the polymorphic uridine 5'-diphospho-glucuronosyltransferase (UGT) 2B17 and cytochrome (CYP) 2C19. A population pharmacokinetic (PK) model was built, using NONMEM® v7.3, based on demographics/PK data from 3 clinical pharmacology (food effect, formulation bridging, genotype/race effect) and 2 clinical (phase 1 dose escalation/expansion in RCC and other solid tumors; phase 2 in VHL patients) studies. Median (range) age for the combined studies was 55 years (19-84) and body weight was 73.6 kg (42.1-165.8). Belzutifan plasma PK was well-characterized by a linear 2-compartment model with first-order absorption and elimination. For VHL patients, the predicted geometric mean (% coefficient of variation [CV]) apparent clearance (CL/F) was 7.3 L/hr (51%), apparent total volume of distribution (Vd/F) was 130 L (35%); and half-life was 12.39 hours (42%). There were no clinically relevant differences in belzutifan PK based on the individual covariates of age, sex, ethnicity, race, body weight, mild/moderate renal impairment, or mild hepatic impairment. In this model dual UGT2B17 and CYP2C19 poor metabolizers (PM) were estimated to have a 3.2-fold higher area under the plasma concentration-time curve (AUC) compared to UGT2B17 extensive metabolizer and CYP2C19 non-PM patients. This population PK analysis enabled an integrated assessment of PK characteristics with covariate effects in overall- and sub-populations for belzutifan labeling.

First, do no harm: surgical management of von Hippel Lindau syndrome

Von Hippel Lindau (VHL) syndrome is an inherited condition that is associated with retinal and central nervous system haemangioblastomas, as well as renal and pancreatic cysts (Varshney et al., 2017). The renal cysts have a significant likelihood of neoplastic change, and act as a pre-malignant pathological finding prior to the development of clear cell renal carcinoma.

Belzutifan in adults with VHL-associated central nervous system hemangioblastoma: a single-center experience.

Belzutifan is a selective inhibitor of hypoxia-inducible factor 2 alpha (HIF-2a) that has emerged as a targeted therapy option for Von Hippel-Lindau (VHL) syndrome-associated tumors with recent FDA approval. There is limited real-world evidence regarding safety and efficacy in CNS hemangioblastoma. Our objective was to report on our clinical experience with belzutifan in adult patients with VHL-associated CNS hemangioblastoma. We retrospectively reviewed our institutional experience of belzutifan in adult patients (> 18 years of age at time of therapy) with VHL and craniospinal CNS hemangioblastomas not amenable to surgical resection. The period for study review was October 2021 to March 2023. 4 patients (all female) with a median age of 36 years at time of belzutifan initiation were included. Median duration of therapy at last follow-up was 11 months (6-17 months). All patients had radiographic response to therapy after a median of 3 months (2-5 months), with maximal response to therapy after a median of 8 months (3-17 months). Therapy was well tolerated, with the most common adverse effect being anemia. No patients had treatment pauses or dose adjustments due to belzutifan-related toxicity. No patients experienced hypoxia. We showed that belzutifan is safe and well-tolerated with strong disease response for CNS hemangioblastoma in adults with VHL, supporting continued use of belzutifan in this patient population. Future studies should assess duration of treatment, effects of cessation after long-term use, and markers of therapeutic response.

Belzutifan treatment of Von Hippel-Lindau (VHL) related central nervous system (CNS) hemangioblastomas (HBs): A single institution experience.

2078 Background: Patients with inactivating germline mutations in the VHL gene develop CNS (brain and/or spine) HBs and/or renal cancers, pheochromocytomas and pancreatic neuroendocrine tumors. The oral HIF2a inhibitor belzutifan has been approved by FDA for the treatment of VHL-related HBs. We present here data on a cohort of VHL patients with CNS HBs treated with belzutifan in a single institution. Methods: Adult VHL patients, with radiologically documented CNS (brain and/or spine) HBs that displayed documented growth within the last 6 months prior to therapy, were treated with an initial dose of 120 mg belzutifan orally per day. Target lesions included HBs &gt; 0.4cm long in one maximal cross-sectional diameter. Lesions were imaged by MRI at 1.5, 3, 6 months after initiation of treatment and at 6-month intervals thereafter. Solid enhancing lesions, associated cysts and peritumoral edema were recorded and quantified. Tumor sizes were evaluated by RECIST 1.1 criteria and volumetric analysis. All patients were evaluated and treated in the Hemangioblastoma Center and the VHL Clinic of the Massachusetts General Hospital Cancer Center. Results: At the time of analysis, 9 females and ten 10 male VHL patients (n=19) have been treated. Median age at treatment initiation was 36 yo (range 19-59). Median follow up is 12 months (range 1-19.5 months). Two patients were not yet evaluable for response. Of 17 evaluable patients, 8 had a PR (ORR 47%; 95% CI, 34-60), 8 had SD and 1 patient had progression (PD, 5.8%). Two patients had dose reduction to 80 mg/d because of anemia. No patient had grade 3 or greater toxicity and no patient experienced a CNS related toxicity during treatment. Volumetric analysis of solid and cystic components of the lesions, VHL germline mutations and other correlates of response to belzutifan will be presented. Conclusions: Real world data collected at a single institution confirm the high response rate of both solid and cystic components of CNS HBs to the FDA approved HIF2a inhibitor, belzutifan. Belzutifan was well tolerated. Further prospective controlled studies addressing the optimal dose, schedule and duration of treatment of HBs with belzutifan are required.

The impact of surgery on patients with VHL-associated tumors: An international patient survey.

4517 Background: Von Hippel-Lindau syndrome (VHL) is a rare hereditary neoplastic disorder caused by mutations in the VHL gene. Treatment (tx) options for patients are limited to multiple surgeries dispersed between regular scans, watchful waiting and txs that preserve organ function. Methods: An international, cross-sectional survey comprising patients in the United States (US), Canada (CA), the United Kingdom (UK), France (FR), and Germany (DE) was conducted. Patients were recruited via the VHL Alliance; data were collected between Dec 2021 and May 2022. For inclusion, patients must have renal cell carcinoma (RCC), pancreatic neuroendocrine tumors (pNET), and/or central nervous system hemangioblastoma (CNS-Hb). Data collected included demographics, impact of most recent surgery on aspects of condition (1-7 scale 1 being greatly worsened and 7 being greatly improved), tx goals (top 3 goals from a list of 11), and patient preference in treatment. Patients were presented two scenarios “watch and wait” and potentially need surgery, or “take a once-daily pill” to delay a potential surgery. Results: 220 patients (68.2% female, median age 40.0, median disease duration 15.8 years) in the US (n=108), CA (n=37), the UK (n=21), FR (n=3), and DE (n=51) completed the study. 146 patients reported RCC (66.4%), n=122 reported pNET (55.5%), and n=190 reported CNS-Hb (86.4%). Among the top 4 symptoms experienced by patients were kidney cysts (n=82, 37.3%), numbness (n=59, 26.8%), dizziness (n=56, 25.5%), and fatigue/low energy (n=54, 24.5%). 205 (93.2%) patients had experienced surgery; n=171 (77.7%) had experienced multiple surgeries (median number of surgeries, 4.0). 166 patients recorded data on their most recent surgery. Of these, patients reported that their most recent surgery worsened (scored 1-3) their fatigue (51.8%), mental health (51.2%), and ability to go about daily life (45.2%). 47.3% of patients selected reduce the number of surgeries as a top tx goal, 46.4% selected being able to go about life as usual, 36.8% delay the need for surgery, and 33.2% improved quality of life. 73% of patients indicated they would prefer to take a pill which would possibly delay the time until surgery, rather than watch and wait to see if the tumor would grow. Conclusions: Surgery negatively impacts the lives of patients, leading to a worsening in their fatigue, mental health, and ability to go about daily life. Almost half of patients would like a treatment that reduces the number of surgeries, and over a third would like a treatment that delays the need for surgery. Nearly three quarters of patients would prefer to take a pill that might delay the need for surgery. Tx options that reduce the need for surgery would benefit this patient group.

Proteostasis Modulation in Germline Missense von Hippel Lindau Disease.

Missense mutated von Hippel Lindau (VHL) protein (pVHL) maintains intrinsic function but undergoes proteasomal degradation and tumor initiation and/or progression in VHL disease. Vorinostat can rescue missense mutated pVHL and arrest tumor growth in preclinical models. We asked whether short-term oral vorinostat could rescue pVHL in central nervous system hemangioblastomas in patients with germline missense VHL. We administered oral vorinostat to 7 subjects (ages 46.0 ± 14.5 years) and then removed symptomatic hemangioblastomas surgically (ClinicalTrials.gov identifier NCT02108002). Vorinostat was tolerated without serious adverse events by all patients. pVHL expression was elevated in neoplastic stromal cells compared with untreated hemangioblastomas from same patients. We found transcriptional suppression of downstream hypoxia-inducible factor (HIF) effectors. Mechanistically, vorinostat prevented Hsp90 recruitment to mutated pVHL in vitro. The effects of vorinostat on the Hsp90-pVHL interaction, pVHL rescue, and transcriptional repression of downstream HIF effectors was independent of the location of the missense mutation on the VHL locus. We confirmed a neoplastic stromal cell-specific effect in suppression of protumorigenic pathways with single-nucleus transcriptomic profiling. We found that oral vorinostat treatment in patients with germline missense VHL mutations has a potent biologic effect that warrants further clinical study. These results provide biologic evidence to support the use of proteostasis modulation for the treatment of syndromic solid tumors involving protein misfolding. Proteostasis modulation with vorinostat rescues missense mutated VHL protein. Further clinical trials are needed to demonstrate tumor growth arrest.

Non-Interventional Management of Advanced Pancreatic Neuroendocrine Neoplasms in Patients with von Hippel-Lindau Disease.

Von Hippel-Lindau (VHL) is a rare autosomal dominant hereditary cancer predisposition syndrome. Patients with VHL have a high risk for developing retinal and central nervous system hemangioblastoma, pheochromocytoma, renal cell carcinoma, and pancreatic neuroendocrine neoplasms (PNEN). About a fifth of patients with VHL will develop PNEN, and only a tenth of them will develop metastatic or unresectable (advanced) PNEN requiring medical intervention. In this review, we performed a literature search for studies, written in English, on the medical interventions for VHL-related localized and advanced PNENs and their clinical outcomes. We detail the various medical interventions for this rare group of patients, including their mode of action and potential efficacy and toxicity. Finally, based on the current literature, we delineate a possible management algorithm for patients with VHL and advanced PNEN. We can conclude that data on the efficacy of various vascular endothelial growth factor (VEGF) receptor inhibitors, and on the efficacy of belzutifan, a novel hypoxia-inducible factor 2 inhibitor, for the management of advanced PNEN in VHL, are scarce. Hence, deduction from the management of sporadic PNEN is required, and is implemented in the proposed management algorithm provided within this review.