Schultz, Sydney E

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.