Browsing by Author "Widemann, Brigitte C."

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    Cabozantinib for neurofibromatosis type 1-related plexiform neurofibromas: a phase 2 trial
    (Springer Nature, 2021-01) Fisher, Michael J.; Shih, Chie-Schin; Rhodes, Steven D.; Armstrong, Amy E.; Wolters, Pamela L.; Dombi, Eva; Zhang, Chi; Angus, Steven P.; Johnson, Gary L.; Packer, Roger J.; Allen, Jeffrey C.; Ullrich, Nicole J.; Goldman, Stewart; Gutmann, David H.; Plotkin, Scott R.; Rosser, Tena; Robertson, Kent A.; Widemann, Brigitte C.; Smith, Abbi E.; Bessler, Waylan K.; He, Yongzheng; Park, Su-Jung; Mund, Julie A.; Jiang, Li; Bijangi-Vishehsaraei, Khadijeh; Robinson, Coretta Thomas; Cutter, Gary R.; Korf, Bruce R.; Blakeley, Jaishri O.; Clapp, D. Wade; Pediatrics, School of Medicine
    Neurofibromatosis type 1 (NF1) plexiform neurofibromas (PNs) are progressive, multicellular neoplasms that cause morbidity and may transform to sarcoma. Treatment of Nf1fl/fl;Postn-Cre mice with cabozantinib, an inhibitor of multiple tyrosine kinases, caused a reduction in PN size and number and differential modulation of kinases in cell lineages that drive PN growth. Based on these findings, the Neurofibromatosis Clinical Trials Consortium conducted a phase II, open-label, nonrandomized Simon two-stage study to assess the safety, efficacy and biologic activity of cabozantinib in patients ≥16 years of age with NF1 and progressive or symptomatic, inoperable PN ( NCT02101736 ). The trial met its primary outcome, defined as ≥25% of patients achieving a partial response (PR, defined as ≥20% reduction in target lesion volume as assessed by magnetic resonance imaging (MRI)) after 12 cycles of therapy. Secondary outcomes included adverse events (AEs), patient-reported outcomes (PROs) assessing pain and quality of life (QOL), pharmacokinetics (PK) and the levels of circulating endothelial cells and cytokines. Eight of 19 evaluable (42%) trial participants achieved a PR. The median change in tumor volume was 15.2% (range, +2.2% to -36.9%), and no patients had disease progression while on treatment. Nine patients required dose reduction or discontinuation of therapy due to AEs; common AEs included gastrointestinal toxicity, hypothyroidism, fatigue and palmar plantar erythrodysesthesia. A total of 11 grade 3 AEs occurred in eight patients. Patients with PR had a significant reduction in tumor pain intensity and pain interference in daily life but no change in global QOL scores. These data indicate that cabozantinib is active in NF1-associated PN, resulting in tumor volume reduction and pain improvement.
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    A molecular basis for neurofibroma-associated skeletal manifestations in NF1
    (Elsevier, 2020-11) Ma, Yun; Gross, Andrea; Dombi, Eva; Pemov, Alex; Choi, Kwangmin; Chaney, Katherine; Rhodes, Steven D.; Angus, Steven P.; Sciaky, Noah; Clapp, D. Wade; Ratner, Nancy; Widemann, Brigitte C.; Rios, Jonathan J.; Elefteriou, Florent; Pediatrics, School of Medicine
    Purpose: Plexiform neurofibromas (pNF) develop in children with neurofibromatosis type 1 (NF1) and can be associated with several skeletal comorbidities. Preclinical mouse studies revealed Nf1 deficiency in osteoprogenitor cells disrupts, in a MEK-dependent manner, pyrophosphate (PPi) homeostasis and skeletal mineralization. The etiology of NF-associated skeletal manifestations remains unknown. Methods: We used mouse models of NF1 neurofibromas to assess bone mineralization of skeletal structures adjacent to tumors. Expression of genes involved in pyrophosphate homeostasis was assessed in mouse and human NF tumors and Schwann cell cultures. We used dual-energy X-ray absorptiometry (DXA) to assess tumor-associated changes in bone mineral density (BMD) in an individual with NF1 following treatment with the MEK inhibitor selumetinib. Results: We detected increased nonmineralized bone surfaces adjacent to tumors in mouse models of NF1 neurofibromas. Expression of Enpp1, a PPi-generating ectophosphatase, and ANKH, a PPi transporter, was increased in mouse and human neurofibroma-derived tissues and Schwann cells, respectively. In one patient, tumor-associated reductions in BMD were partially rescued following therapy with selumetinib. Conclusion: Results indicate that NF-associated skeletal pathologies in NF1 are associated with dysregulated pyrophosphate homeostasis in adjacent NF tumors and suggest that treatment of NFs with MEK inhibitors may improve skeletal manifestations of the disease.
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    NFS-18. Lower Body Surface Area is Associated with Increased Likelihood of Plexiform Neurofibroma Response to MEK Inhibition
    (Oxford University Press, 2024-06-18) Kotch, Chelsea; Dombi, Eva; Gross, Andrea; Weiss, Brian; Mueller, Sabine; Reddy, Alyssa T.; Perreault, Sébastien; Alves, Mélanie; Brown, Symone; Li, Yimei; Widemann, Brigitte C.; Fisher, Michael J.; Pediatrics, School of Medicine
    BACKGROUND: MEK inhibitors (MEKi) are altering the management approach for plexiform neurofibroma (PN), with high rates of treatment response to multiple MEKi. Despite these successes, a subset of PN fail to respond and little is known about the clinical features associated with treatment response. METHODS: We performed a retrospective cohort study integrating clinical trial data (NCT01362803, NCT02407405, NCT02096471, NCT03231306, NCT03363217) to identify baseline clinical features associated with response of PN to MEKi. Partial response (PR) was defined as ≥20 percent reduction in tumor volume from baseline. RESULTS: Of 232 eligible participants, adequate clinical trial and imaging data was available for 223 participants. In the primary analysis of 184 participants with central response evaluation, the median age was 15.2 years with a median tumor volume of 488 milliliters at clinical trial enrollment. One hundred and eighteen (64%) participants achieved a PR with median time to PR of 8 cycles. Thirty-five participants (19%) required a dose reduction prior to 6 cycles of therapy due to toxicity. Younger age and lower body surface area (BSA) were significantly associated with PR in univariate analysis while female sex and typical PN appearance (versus nodular) on imaging approached significance. In multivariable analysis, only lower BSA was significantly associated with response while typical PN appearance approached significance. In the multivariable analysis of pediatric participants treated per BSA-based dosing, lower BSA was the only feature significantly associated with PR. In the expanded analysis of all 223 participants, lower BSA and typical PN appearance were significantly associated with PR. CONCLUSION: Lower BSA and typical appearance of PN were associated with PR to MEK inhibitors. Future studies of MEK inhibitor for PN should integrate tumor pharmacokinetic-pharmacodynamic analyses to prospectively explore the impact of BSA on treatment response.
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    SARC006: Phase II Trial of Chemotherapy in Sporadic and Neurofibromatosis Type 1 Associated Chemotherapy-Naive Malignant Peripheral Nerve Sheath Tumors
    (Hindawi, 2017) Higham, Christine S.; Steinberg, Seth M.; Dombi, Eva; Perry, Arie; Helman, Lee J.; Schuetze, Scott M.; Ludwig, Joseph A.; Staddon, Arthur; Milhem, Mohammed M.; Rushing, Daniel; Jones, Robin L.; Livingston, Michael; Goldman, Stewart; Moertel, Christopher; Wagner, Lars; Janhofer, David; Annunziata, Christina M.; Reinke, Denise; Long, Lauren; Viskochil, David; Baker, Larry; Widemann, Brigitte C.; Department of Medicine, School of Medicine
    Background. Worse chemotherapy response for neurofibromatosis type 1- (NF1-) associated compared to sporadic malignant peripheral nerve sheath tumors (MPNST) has been reported. Methods. We evaluated the objective response (OR) rate of patients with AJCC Stage III/IV chemotherapy-naive NF1 MPNST versus sporadic MPNST after 4 cycles of neoadjuvant chemotherapy, 2 cycles of ifosfamide/doxorubicin, and 2 cycles of ifosfamide/etoposide. A Simon optimal two-stage design was used (target response rate 40%). Results. 34 NF1 (median age 33 years) and 14 sporadic (median age 40 years) MPNST patients enrolled. Five of 28 (17.9%) evaluable NF1 MPNST patients had a partial response (PR), as did 4 of 9 (44.4%) patients with sporadic MPNST. Stable disease (SD) was achieved in 22 NF1 and 4 sporadic MPNST patients. In both strata, results in the initial stages met criteria for expansion of enrollment. Only 1 additional PR was observed in the expanded NF1 stratum. Enrollment was slower than expected and the trial closed before full accrual. Conclusions. This trial was not powered to detect differences in response rates between NF1 and sporadic MPNST. While the OR rate was lower in NF1 compared to sporadic MPNST, qualitative responses were similar, and disease stabilization was achieved in most patients.
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    Sleep and pulmonary outcomes for clinical trials of airway plexiform neurofibromas in NF1
    (AAN, 2016-08) Plotkin, Scott R.; Davis, Stephanie D.; Robertson, Kent A.; Akshintala, Srivandana; Allen, Julian; Fisher, Michael J.; Blakely, Jaishri O.; Widemann, Brigitte C.; Ferner, Rosalie E.; Marcus, Carole L.; Department of Pediatrics, School of Medicine
    Objective: Plexiform neurofibromas (PNs) are complex, benign nerve sheath tumors that occur in approximately 25%–50% of individuals with neurofibromatosis type 1 (NF1). PNs that cause airway compromise or pulmonary dysfunction are uncommon but clinically important. Because improvement in sleep quality or airway function represents direct clinical benefit, measures of sleep and pulmonary function may be more meaningful than tumor size as endpoints in therapeutic clinical trials targeting airway PN. Methods: The Response Evaluation in Neurofibromatosis and Schwannomatosis functional outcomes group reviewed currently available endpoints for sleep and pulmonary outcomes and developed consensus recommendations for response evaluation in NF clinical trials. Results: For patients with airway PNs, polysomnography, impulse oscillometry, and spirometry should be performed to identify abnormal function that will be targeted by the agent under clinical investigation. The functional group endorsed the use of the apnea hypopnea index (AHI) as the primary sleep endpoint, and pulmonary resistance at 10 Hz (R10) or forced expiratory volume in 1 or 0.75 seconds (FEV1 or FEV0.75) as primary pulmonary endpoints. The group defined minimum changes in AHI, R10, and FEV1 or FEV0.75 for response criteria. Secondary sleep outcomes include desaturation and hypercapnia during sleep and arousal index. Secondary pulmonary outcomes include pulmonary resistance and reactance measurements at 5, 10, and 20 Hz; forced vital capacity; peak expiratory flow; and forced expiratory flows. Conclusions: These recommended sleep and pulmonary evaluations are intended to provide researchers with a standardized set of clinically meaningful endpoints for response evaluation in trials of NF1-related airway PNs.