Schultz, Sydney

Abstract Purpose Bevacizumab is an effective treatment for radiation necrosis; dose dependent radiographic and edema response data are lacking. Methods Multicenter, retrospective cohort study of adult patients with primary central nervous system tumors or brain metastases who received bevacizumab for radiation necrosis between June 2021 and July 2024. Patients were grouped by bevacizumab dose (7.5 mg/kg vs 10 mg/kg administered every three weeks). Primary outcome was edema response, assessed by a blinded neuro-oncologist. Secondary outcomes included contrast enhancing disease response, clinical response, adverse events, treatment discontinuation, and re-dosing for recurrent radiation necrosis. Analyses were performed with and without adjustment for tumor type. Results 104 patients were included (7.5 mg/kg, n = 53; 10 mg/kg, n = 51). Edema response differed between dosing groups in unadjusted analyses (p = 0.032), favoring the 7.5 mg/kg cohort; however, this association was attenuated after adjustment for tumor type. Contrast enhancing disease response did not differ between groups in either unadjusted or adjusted analyses (p = 0.43). Clinical response was higher in the 7.5 mg/kg group (65.2% vs 37.8%, p = 0.013). Tumor type differed significantly between cohorts (p < 0.001), with more primary CNS tumors in the 10 mg/kg group. Rates of adverse events, treatment discontinuation, and re-dosing were similar. Conclusions While lower-dose bevacizumab was associated with greater edema reduction in unadjusted analyses, this effect was attenuated after accounting for tumor type. Importantly, 7.5 mg/kg dosing appeared sufficient for achieving edema control and contrast enhancing disease response. These findings support an individualized approach to bevacizumab dosing in radiation necrosis and highlight the need for prospective, tumor-stratified studies.

Abstract Background Isocitrate dehydrogenase-1 (IDH-1) inhibitor ivosidenib and dual-IDH1/2 inhibitor vorasidenib have demonstrated clinical activity in the treatment of IDH-mutant gliomas. We evaluated the efficacy of vorasidenib in patients with prior exposure to ivosidenib. Methods Retrospective review of patients with IDH-mutant glioma treated with vorasidenib who had prior treatment with ivosidenib. Previous treatments, radiographic response, and adverse events were collected and analyzed descriptively. Results Twenty-nine patients (median age 42, 34% female) were evaluated. Tumor types included IDH-mutant astrocytoma (grade 2 n = 9, 31%; grade 3 n = 3, 10%; grade 4 n = 3, 10%) and oligodendroglioma (grade 2 n = 10, 34%; grade 3 n = 4, 14%). Treatments received prior to ivosidenib included surgical resection (n = 23, 79%), radiation (n = 16, 55%), temozolomide (n = 15, 52%), procarbazine, lomustine, vincristine (PCV, n = 2, 7%), bevacizumab (n = 3, 10%), lomustine (n = 2, 7%), and pembrolizumab (n = 1, 3%). Four patients received additional treatment in between ivosidenib and vorasidenib treatment. Ten of 16 (63%) patients who experienced disease progression on ivosidenib achieved stable disease and remain on vorasidenib, while 6 (37%) had continued progression. Eleven patients with stable disease on ivosidenib transitioned to vorasidenib following FDA approval and remained without progression. Two patients who transitioned to vorasidenib due to ivosidenib-related adverse effects (diarrhea and fatigue) experienced symptom resolution and maintained disease stability. Conclusions Vorasidenib demonstrated clinical efficacy in patients with IDH-mutant gliomas previously treated with ivosidenib. Notably, stable patients who transitioned maintained disease stability, while some of those with progressive disease achieved stabilization with vorasidenib. These findings support vorasidenib as a viable therapeutic option following ivosidenib exposure.

PURPOSE The difference in time to serum calcium normalization and rates of subsequent refractory hypocalcemia between bisphosphonates requires further investigation. Our primary objective was to assess the difference in normalization of serum calcium between pamidronate and zoledronic acid during treatment of hypercalcemia of malignancy (HCM) and rates of subsequent, refractory hypocalcemia following therapy. METHODS A retrospective review of patients with cancer who received pamidronate or zoledronic acid inpatient at Mayo Clinic for treatment of HCM between January 2018 and January 2024 was conducted. Logistic regression evaluated the association between treatment groups and outcomes. Multivariable modeling was adjusted for baseline differences, including severity of hypercalcemia. RESULTS We evaluated 856 patients. The median age was 68 (IQR, 59-75) years, and 476 (55.6%) were male. The most common cancer diagnoses were lymphoma (n = 158, 18.5%), followed by multiple myeloma (n = 145, 16.9%) and lung cancer (n = 111, 13%). Overall, 292 (46.8%) patients and 154 (32.8%) patients achieved serum calcium normalization by hospital day 4 and day 7, respectively. The rate of normalization was similar between all bisphosphonates, regardless of pamidronate dose. Significantly higher rates of hypocalcemia were observed on day 4 for patients who received zoledronic acid 4 mg once compared with either dose (60 mg once and 90 mg once) of pamidronate (40.7% v 27.6% v 26.8%, P = .049, respectively). No significant difference in rates of hypocalcemia were observed on day 7 (56.8% v 50% v 42.9%, P = .26, respectively) and day 30 (39.1% v 39.0% v 37.5%, P = .50, respectively). CONCLUSION Bisphosphonates were equally efficacious in normalizing serum calcium in patients with HCM. Pamidronate 90 mg was not more efficacious than 60 mg. Rates of refractory hypocalcemia were similar.

Abstract BACKGROUND The IDH inhibitor vorasidenib was FDA-approved for treatment of IDH-mutant grade 2 gliomas in August 2024. We evaluated vorasidenib in patients with grade 3 and 4 IDH-mutant gliomas who would not have been eligible for the INDIGO trial. METHODS Retrospective review of patients with grade 3 or 4 IDH-mutant gliomas treated with vorasidenib between 9/1/24 and 5/31/25. Prior treatments, radiographic response, adverse events and seizure control were collected for each patient. RESULTS Thirty-two patients (median age 39.5, 46.9% female) met inclusion criteria. Tumor types included grade 3 oligodendroglioma (11, 34.4%), grade 3 astrocytoma (13, 40.6%) and grade 4 astrocytoma (8, 25%). Thirty patients had contrast-enhancement; 2 patients had non-enhancing tumor. Prior treatments included surgical resection (30, 93.8%), radiation (27, 84.4%), cytotoxic chemotherapy (25, 78.1%), bevacizumab (5, 15.6%), pembrolizumab (3, 9.4%), and ivosidenib (8, 25%). Four patients (12.5%) were naïve to systemic treatment at the time of vorasidenib initiation. Median duration of vorasidenib was 101.5 days (range 18-255) with 19 patients still on vorasidenib at the time of last follow-up. Seventeen patients (53.1%) had stable disease, 11 (34.4%) had progressive disease, 2 (6.3%) did not yet have response assessment, and 2 (6.3%) died. Grade 1 transaminitis occurred in 12 patients with no high grade transaminitis. Two patients developed lymphopenia; both were heavily pre-treated with multiple alkylating agents; no other hematologic toxicity was noted. One patient developed myalgias leading to vorasidenib discontinuation. Nine patients had fatigue, 4 headaches, 2 nausea, 2 decreased appetite. In patients with a history of epilepsy, there were no reported seizures. CONCLUSIONS Vorasidenib was well-tolerated in this heavily pre-treated cohort of grade 3–4 IDH-mutant gliomas, with low-grade transaminitis and fatigue being the most common toxicities. Preliminary results show disease stability in 53.1% of patients after a median of 3.5 months. Conclusions are limited by short-interval follow-up.

Abstract BACKGROUND Tovorafenib is a type II rapidly accelerated fibrosarcoma (RAF) kinase inhibitor approved by the FDA in 2024 for relapsing or chemotherapy-refractory pediatric low-grade gliomas with mutations or alterations in the gene BRAF. There is potential for the use of this drug outside the pediatric population. We present a single institution case series of adults with CNS tumors with mutations or alterations in BRAF treated (off-label) with tovorafenib. METHODS Chart review. RESULTS 8 adult (age &gt;18) patients were treated with tovorafenib at our institution between March 2024 and June 2025. Age range was 21-66 years old (median age 42). The population included 5 males and 3 females. Indications for treatment were pilocytic astrocytoma (n = 2), high grade astrocytoma with piloid features (HGAP) (n = 2), Erdheim-Chester disease (n = 2), pleomorphic xanthoastrocytoma (n = 1), and otherwise unclassified low-grade glioma (n = 1). All patients had mutations or alterations in BRAF including KIAA1549 fusion (n = 4), V600E mutation (n = 3), or GAB2 fusion (n = 1). Radiographic response to therapy was seen in 5/8 patients with 3 cases of radiographic stability (though one patient later progressed) and 2 cases of decrease in tumor size (in a pilocytic astrocytoma and in an HGAP). Both cases of decreased tumor size after treatment were in tumors with KIAA1549 fusions. Adverse effects of tovorafenib included fatigue (n=2), headache, myalgias, diplopia, cytopenias, and transaminitis (n=1). 3/8 patients had to pause or stop treatment due to adverse effects (intolerable headache, cytopenias, and transaminitis respectively). CONCLUSION Tovorafenib is a promising new treatment for CNS tumors with BRAF mutations or alterations. Our single institution case series suggests the efficacy of this drug for multiple tumor types in adults. Certain tumor subtypes such as KIAA1549 fusions may be more likely to benefit from this treatment.

Abstract BACKGROUND Bevacizumab, an anti-vascular endothelial growth factor (VEGF) monoclonal antibody, has emerged as a treatment for radiation necrosis. Doses ranging from 2.5 mg/kg to 15 mg/kg have been utilized however the optimal dosing remains inadequately studied. METHODS Retrospective review of adult patients with central nervous system tumors or brain metastasis treated with bevacizumab from 6/29/2021 to 7/31/2024. Patients were divided into those who received bevacizumab 7.5 mg/kg every 21 days and those who received bevacizumab 10 mg/kg every 21 days. The primary outcome was radiographic response as assessed by a blinded neuro-oncologist. Secondary outcomes included clinical response as documented in clinical notes, major adverse events including hemorrhage and thromboembolic events and re-dosing for recurrence of radiation necrosis beyond the 4 initially planned doses. RESULTS 104 patients were included (median age 59.3 years, 55% male); 53 patients in the 7.5 mg/kg group and 51 patients in the 10 mg/kg group. In the 7.5 mg/kg group, 1 patient had a complete response (CR), 16 patients had a partial response (PR), 32 patients had stable disease (SD), 3 patients had progression of disease, and 1 patient did not have repeat imaging. Of the 51 patients in the 10 mg/kg group, 3 patients had a CR, 10 patients had a PR, 27 patients had SD, 5 patients had progression of disease, and 6 patients did not have repeat imaging. There was no statistically significant difference in radiographic response between the two dosing groups (p = 0.42). Clinical response rates were higher in the 7.5 mg/kg group (65.2% vs 37.8%, p = 0.013). Major adverse events and need for re-dosing for radiation necrosis recurrence were comparable. CONCLUSION Bevacizumab 7.5 mg/kg was equally as efficacious as 10 mg/kg in terms of radiographic response and may offer a better clinical response for patients with radiation necrosis.

Abstract BACKGROUND Access to in-person evaluations is challenging for patients with glioma due to disease-related disability and distance from specialized neuro-oncology centers. Telehealth is an alternative to in-person evaluations, but acceptability of and therapy compliance with this model has not been prospectively evaluated. METHODS In this single-arm non-randomized pragmatic clinical trial, we compared patient satisfaction with telehealth and in-person assessments among patients with glioma undergoing chemotherapy with temozolomide. Participants acted as their own controls, alternating between telehealth and in-person visits. Patient satisfaction with care delivered was evaluated by Press-Ganey surveys with Likert response scales (1-5, 1=very poor, 5=very good). A digital pill diary (DPD) was implemented to track chemotherapy compliance. RESULTS We accrued 30 patients (median age 59, 38% female) between October 2024 and May 2025. Half of the patients (n=15) reported a primary residence greater than 150 miles from our institution. Surveys from 25 participants were reviewed, with 17/25 completing one or more surveys following an in-person visit, and 21/25 completing one or more surveys following a telehealth visit. Overall average Press-Ganey scores were similar between the two visit modalities with high scores (telehealth=4.8; in-person=4.7). Median scores for specific modalities were similarly highly rated: likelihood of recommending practice to others (telehealth=5.0; in-person=5.0), concern the care provider showed (telehealth=5.0, in-person=4.7), provider’s discussion of treatment options (telehealth=5.0, in-person=5.0), provider effort to include patients in decision-making (telehealth=5.0, in-person=5.0). DPDs used to monitor treatment compliance indicated adherence to all prescribed doses of temozolomide in 75/79 cycles; the other 4 (of 79) treatment cycles were halted per provider instructions. CONCLUSION This interim assessment demonstrates feasibility of treating patients with similar patient satisfaction of care delivered between telehealth and in-person visits. The DPD was effective in tracking chemotherapy administration. Additional results including visit type preference and acute care utilization data are maturing.

Abstract BACKGROUND Pembrolizumab elicits durable responses in many solid tumors, yet activity in gliomas has been limited. Lymphopenia has been reported in association with reduced survival and a shorter time to progression on checkpoint inhibition in other solid tumors. We evaluated whether low absolute lymphocyte count (ALC) is related to worse outcomes in pembrolizumab-treated patients with gliomas. METHODS In this single-center retrospective study, we identified adults with gliomas who received ≥1 dose of pembrolizumab and had available lymphocyte counts at our center between 05/01/2018 and 1/31/2025. Patients’ demographics, dexamethasone use, baseline ALC (before initiation of pembrolizumab), and clinical outcomes were collected. Overall Survival (OS) was estimated using Kaplan–Meier analysis from the date of starting pembrolizumab to the date of death. RESULTS Ninety patients met eligibility criteria (glioblastoma [GBM] n = 44, astrocytoma n = 20, oligodendroglioma n = 13, meningioma n = 8, other n = 5); 62% were male and 31% (n = 28) harbored IDH-mutant tumors. Across all histological subtypes, baseline ALC&lt;750 cells/mm³ was associated with significantly shorter OS compared to baseline ALC≥750 cells/mm³ (3.7 vs 7.7 months, P = 0.0063) with similar dexamethasone exposure (63% vs 52%). In the recurrent GBM subgroup (n = 43; MGMT-methylated 26%), ALC≥750 cells/mm³ correlated with longer OS (8.5 vs 3.4 months, P = 0.0065) with a slightly lower proportion of patients on dexamethasone in high ALC group (52% vs 75%). Conversely, among patients with IDH-mutant gliomas (n = 28), no significant difference in OS was observed based on ALC levels (7.8 vs. 7.3 months, P = 0.58) with similar dexamethasone use (57% and 43% in high and low ALC groups, respectively). CONCLUSION Baseline lymphopenia preceding pembrolizumab treatment is associated with shorter OS in patients with GBM, but not in IDH-mutant gliomas. These associations require further validation in additional patient cohorts.

Abstract BACKGROUND Von Hippel-Lindau (VHL) disease is a hereditary cancer syndrome characterized by development of multiple neoplasms, including central nervous system (CNS) hemangioblastomas, renal cell carcinoma (RCC), pancreatic neuroendocrine tumors (pNETs), and retinal hemangioblastomas. Belzutifan, a hypoxia-inducible factor 2-alpha (HIF-2α) inhibitor, has demonstrated efficacy in treating VHL-associated tumors. This study evaluates our institutional experience with belzutifan in patients with VHL-related tumors. MATERIAL AND METHODS We conducted a retrospective cohort study across three Mayo Clinic sites, including patients aged ≥18 years with genetically confirmed VHL disease who received belzutifan between October 2021 and March 2025. Clinical/radiological data, and adverse events (AEs) were extracted from electronic health records. Tumor responses were assessed using RECIST v1.1 criteria for RCC, pNET, CNS hemangioblastoma. Retinal hemangioblastoma responses were evaluated through ophthalmologic assessments. RESULTS Forty-five patients were included (median age 44 58% female). Sixty-seven percent had RCC, 91% had CNS hemangioblastomas, 53% had pNETs, and 62% had retinal hemangioblastomas. The median duration of belzutifan therapy was 22.6 months (range 1.0-41.4 months). Among patients with RCC (n=26), overall response rate (ORR) was 19% and median time to best response (MTBR) was 7.4 months. Five patients had partial response (PR), 15 had stable disease (SD), and 1 had progressive disease (PD). For CNS hemangioblastomas (n=41), ORR was 12%, MTBR was 6.2 months. 5 patients had PR, 30 had SD, and none had PD. For pNET (n=17), ORR was 41%, MTBR was 8.2 months. One patient had CR, 6 patients had PR, 6 had SD, none had PD. For retinal hemangioblastomas (n=28), 6 (21%) showed improvement, 9 (32%) remained stable, and 3 (11%) showed progression. MTBR was 6.7 months. Treatment-related AEs occurred in 98% of patients. Common AEs included anemia (89%), fatigue (80%), hypoxia (18%), and headache (13%). Grade 3 AEs were observed in 20% of patients, including anemia (7%), hypoxia (9%), fatigue (4%), pneumonitis (2%), loss of consciousness (2%). One patient experienced a grade 4 event (status epilepticus). Anemia management involved iron supplementation (n=11), RBC transfusion (n=3), dose reduction (n=2), treatment holiday (n=8), permanent discontinuation (n=1). Hypoxia management included dose reduction (n=1), treatment holiday (n=3), discontinuation (n=1). CONCLUSION Belzutifan shows clinical activity across various VHL-associated neoplasms in real-world practice, with a manageable safety profile. The lower ORR compared to the phase III trial may reflect differences in baseline disease, including lower tumor burden in our cohort. These findings support its continued use in VHL disease, with attention to monitoring and managing treatment-related AEs.