Background Chronotherapy is an innovative approach to improving survival through timed delivery of anti-cancer treatments according to patient daily rhythms. Temozolomide (TMZ) is a standard-of-care chemotherapeutic agent for glioblastoma (GBM). Whether timing of TMZ administration affects GBM patient outcome has not previously been studied. We sought to evaluate maintenance TMZ chronotherapy on GBM patient survival. Methods This retrospective study reviewed patients with newly diagnosed GBM from 1/1/2010 to 12/31/2018 at Washington University School of Medicine who had surgery, chemoradiation, and were prescribed TMZ to be taken in the morning or evening. The Kaplan Meier method and Cox regression model were used for overall survival (OS) analyses. The propensity score method accounted for potential observational study biases. The restricted mean survival time (RMST) method was performed where the proportional hazard assumption was violated. Results We analyzed 166 eligible GBM patients with a median follow-up of 5.07 years. Patients taking morning TMZ exhibited longer OS compared to evening (median OS, 95% CI =1.43,1.12~1.92 vs. 1.13,0.84~1.58 years) with a significant year 1 RMST difference (-0.09, 95% CI:-0.16~-0.018). Among MGMT-methylated patients, median OS was 6 months longer for AM patients with significant RMST differences at years 1 (-0.13, 95% CI=-0.24~-0.019) to 2.5 (-0.43, 95% CI=-0.84~-0.028). Superiority of morning TMZ at years 1, 2 and 5 (all p<0.05) among all patients was supported by RMST difference regression after adjusting for confounders. Conclusions Our study presents preliminary evidence for the benefit of TMZ chronotherapy to GBM patient survival. This impact is more pronounced in MGMT-methylated patients.

Background Gliomas are the most common primary brain tumor in adults. Current treatments involve surgery, radiation, and temozolomide (TMZ) chemotherapy, however prognosis remains poor and new approaches are required. Circadian medicine aims to maximize treatment efficacy and/or minimize toxicity by timed delivery of medications in accordance with the daily rhythms of the patient. We published a retrospective study showing greater anti-tumor efficacy for morning, relative to evening, administration of TMZ in patients with glioblastoma. We conducted this prospective randomized trial to determine the feasibility, and potential clinical impact, of TMZ chronotherapy in patients with gliomas (NCT02781792). Methods Adult patients with gliomas (WHO Grade II-IV) were enrolled prior to initiation of monthly TMZ therapy and were randomized to receive TMZ either in the morning (AM) before 10 am or in the evening (PM) after 8 pm. Pill diaries were recorded to measure compliance and FACT-Br Quality of Life (QoL) surveys were completed throughout treatment. Study compliance, adverse events (AE), and overall survival were compared between the two arms. Results A total of 35 evaluable patients, including 21 with GBM, were analyzed (18 AM patients and 17 PM patients). Compliance data demonstrated feasibility of timed TMZ dosing. There were no significant differences in AEs, QoL, or survival between the arms. Conclusions Chronotherapy with TMZ is feasible. A larger study is needed to validate the effect of chronotherapy on clinical efficacy.

Background The blood brain barrier (BBB) is a major limiting factor for drug delivery in brain tumors. Laser interstitial thermal therapy (LITT) disrupts the peritumoral BBB. In this study, we examine survival in patients with recurrent glioblastoma (GBM) treated with LITT followed by low-dose doxorubicin, a potent anti-neoplastic drug with poor BBB permeability. Methods Forty-one patients with recurrent GBM were enrolled; thirty patients were evaluable. Participants underwent LITT followed by 6 weekly doxorubicin treatments starting within one week (Early Arm) or at 6-8 weeks (Late Arm) after LITT. The overall survival (OS), local progression-free survival (PFS), and any PFS were compared to historical controls treated with bevacizumab salvage therapy (n = 50) or LITT with standard BBB-permeable salvage therapy (n = 28). Cox proportional hazards models examined the contribution of age, gender, MGMT promoter status, and IDH-mutation status on any PFS and OS. Adverse events were also cataloged. Results The Late Arm and all patients (Early Arm + Late Arm) demonstrated significant improvement in OS compared to historical controls treated with bevacizumab (p < 0.001) and LITT with standard salvage therapy (p < 0.05). No significant difference in any PFS was observed between either arm and historical controls. Low-dose doxorubicin was well-tolerated with comparable adverse event rates between the arms. Conclusions Low-dose doxorubicin given after LITT is well tolerated and correlated with higher OS compared to historical controls treated with bevacizumab or LITT with standard salvage chemotherapy. A larger study is needed to further characterize survival and progression patterns.

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TPS2070 Background: Recurrent glioblastoma (rGBM) after chemoradiotherapy has a dismal outcome with very limited treatment options. Addition of reirradiation to bevacizumab appears to improve progression-free survival (PFS) but does not improve overall survival (OS). Immune checkpoint inhibitors of programmed cell death-1 (PD-1) pathway appear to have limited single-agent activity for rGBM due to its immunesuppressive microenvironment. Indoleamine 2,3 dioxygenase 1 (IDO1) is an inducible and rate-limiting enzyme that catabolizes tryptophan (Trp) into kynurenine (Kyn). IDO1 is over-expressed in 50̃90% of GBM patients, and high IDO1 levels correlate with reduced OS. Epacadostat is a highly potent and selective oral inhibitor of IDO1 and may increase tumor sensitivity to anti-PD-1 blockade. Retifanlimab is a humanized anti-PD-1 monoclonal antibody directed against PD-1. The purpose of this study is to evaluate the safety and efficacy of combining retifanlimab plus or minus epacadostat with reirradiation and bevacizumab for rGBM patients. Methods: This is an open-label nonrandomized phase II study of two sequential cohorts for bevacizumab-naïve adults with rGBM: retifanlimab + bevacizumab+ radiation (cohort A), and retifanlimab + epacadostat + bevacizumab + radiation (cohort B). Each cohort will enroll 24 evaluable patients. Key eligibility criteria include candidates for reirradiation and bevacizumab, age ≥ 18 years, Karnofsky performance status ≥ 60%, and dexamethasone dose ≤ 4 mg/day. The primary endpoint is OS. Secondary endpoints include PFS, neurologic functions, and toxicity. The correlative endpoints include studies assess the anti-glioma immune response, serum Kyn/Trp ratio, and RNA expression of IDO1 and PD-L1 from available tissue. The trial is actively enrolling. At the time of abstract submission, 16 of the planned 24 patients in Cohort A have been enrolled. Clinical trial information: NCT03532295. [Table: see text]