Posterior Reversible Encephalopathy Syndrome (PRES) and Drug-Induced Hypersensitivity Syndrome (DIHS) following Immunotherapy and BRAF/MEK Inhibition with Continued Response in Metastatic Melanoma

Background. The role of immunotherapy continues to evolve across both solid and hematologic malignancies. However, while use of immunotherapy has increased via the advent of checkpoint inhibition, chimeric antigen receptors, and vaccines against malignant cells, there remains uncertainty regarding the recognition and management of delayed immune-related reactions and post treatment immune-related sensitivity to subsequent medications, such as BRAF/MEK kinase inhibitors. Furthermore, it is unclear how immunotherapy may alter the adverse effect profile and efficacy of subsequent lines of treatment. Case Presentation. Discussed is a patient with stage IV metastatic melanoma who failed first-line treatment with a combination of nivolumab and ipilimumab. He was then treated with BRAF/MEK kinase inhibition via Encorafenib and Binimetinib. Shortly thereafter, the patient developed posterior reversible encephalopathy syndrome (PRES) and a generalized pruritic rash that was biopsied with consideration toward drug reaction versus drug-induced hypersensitivity syndrome (DIHS), formerly called drug reaction with eosinophilia and systemic symptoms (DRESS). The BRAF/MEK combination was held and steroid taper initiated with continued response even beyond conclusion of the steroid taper. Discussion and Conclusions. This case highlights the diagnostic challenge presented by PRES and DIHS in the setting of immunotherapy and BRAF/MEK kinase inhibition for malignant melanoma. The clinical rationale for reinitiating therapy following severe immune reactions subsequent to immunotherapy in the setting of relapsed/refractory metastatic melanoma is discussed. Additionally, the durable response our patient experienced throughout the drug hold period and steroid taper and its clinical potential etiologies and applications are reviewed. As checkpoint inhibition and tyrosine-kinase inhibitors have become cornerstones of cancer therapy, larger studies and long-term observations are needed to investigate the risks and benefits across different sequences of therapy.

OS8.7 Targeting Pi3k-Akt-mTOR and MAPKinase pathways in aggressive meningiomas: in vitro study

BACKGROUND Recurrent and aggressive meningiomas remain an unmet medical need in neuro-oncology. In our preclinical model on meningioma primary cell culture, the combination of the mTOR inhibitor, everolimus and the somatostatin analog, octreotide decreased cell viability and proliferation without inducing apoptosis. The interest of the combined treatment everolimus plus octreotide were clinically validated by the CEVOREM clinical trial demonstrating a decrease in growth rate of meningiomas in most treated patients. Nevertheless, everolimus induced an increase in Akt activity in vitro, which probably limited everolimus efficiency. We hypothesized that targeting Pi3K could prevent this positive feedback on Akt phosphorylation, induced by mTOR inhibition. The involvement of MAPKinase pathway in meningioma tumorigenesis was recently demonstrated. Our aim was to decipher the effect of the Pi3k α inhibitor Alpelisib (BYL719) and the specific inhibitor of MEK1,2 Mekinist (Trametinib) alone or in combination, in comparison to the mTor inhibitor everolimus on human meningioma primary cell cultures. MATERIAL AND METHODS The impact of the drugs was studied on 40 meningiomas, well characterized at clinical, histological and molecular level. The cell viability, cell proliferation and apoptosis were analyzed under drugs. RESULTS BYL719 induced a dose dependent decrease in cell viability (maximal effect -90%, IC50 10-6M) in all tested meningiomas (n=30). This effect was stronger than those of everolimus (maximal effect -50%, n=24, IC50 10-8M). 22 tumors were sensitive to Trametinib (maximal effect <-50%, IC50 10–5 M), 14 were partially sensitive (maximal effect between -20 and -40% IC50 10–5 M) and 3 were resistant. An apoptotic effect was observed under BYL719 in 6/18 tested tumors whereas no apoptosis was observed under Trametinib and Everolimus. Combination of BYL719 and Trametinib induced a significant stronger decrease in cell viability than each drug alone. Correlation analysis between these functional results, the tumor genomic profile and the activation of ERK/MEK kinase pathway is ongoing. CONCLUSION PI3K-Akt-mTOR and ERK/MEK kinase pathways constitute relevant targets in aggressive meningioma therapy. In our preclinical model, previously validated by CEVOREM clinical trial, co-targeting Pi3k-Akt-mTOR and MAPkinase pathways improved cell proliferation inhibition in comparison to the target of each pathway alone. BYL719 induced apoptosis which was not achieved by everolimus. These results support the ongoing clinical trial ALTREM combining Alpelisib and Trametinib on patients harboring aggressive recurrent meningiomas.