An evaluation of overall survival in patients with newly diagnosed acute myeloid leukemia and the relationship with glasdegib treatment and exposure

Abstract

Purpose Glasdegib, an oral inhibitor of the Hedgehog signaling pathway, is approved in the United States in combination with low-dose cytarabine (LDAC) to treat patients with newly diagnosed acute myeloid leukemia (AML) ineligible to receive intensive chemotherapy. This population pharmacokinetic/pharmacodynamic analysis characterized the time course of survival with glasdegib + LDAC relative to LDAC alone, and explored whether the differences in glasdegib exposure at the clinical dose of 100 mg once daily (QD) significantly affected overall survival (OS). Methods Data from the BRIGHT AML 1003 trial in patients with AML were included in treatment–response (glasdegib + LDAC, n = 78; LDAC alone, n = 38) and exposure–response (glasdegib + LDAC, n = 75) analyses. Results The analyses demonstrate that patients treated with glasdegib + LDAC (vs LDAC alone) at any time point during the study period were 58% less likely to die, translating to prolonging of median OS by ~ 5 months (hazard ratio 0.42 [95% confidence interval 0.28–0.66]). Variability in glasdegib exposures did not impact the risk of death. Additionally, potential covariates such as patient demographics, prior treatment with a hypomethylating agent, baseline safety laboratory values, and disease characteristics, did not impact the probability of OS. Conclusion Together these results confirm that glasdegib + LDAC treatment (vs. LDAC alone) is associated with a significant survival benefit in patients with newly diagnosed AML, and that variability in glasdegib doses (e.g., for dose reductions) and exposures do not compromise the survival benefit of glasdegib 100 mg QD. Clinical Trial number NCT01546038.

Inhibition of EZH2 by chidamide exerts antileukemia activity and increases chemosensitivity through Smo/Gli-1 pathway in acute myeloid leukemia

“…Smo inhibitors improve therapeutic efficacy by sensitizing dormant LSCs to chemotherapy and overcoming microenvironment-induced chemoresistance, and targeting Gli-1 also suppresses proliferation and enhances chemosensitivity in AML cells and progenitor cells [ 65 – 67 ]. Clinical studies have demonstrated that in combination chemotherapy, Smo inhibitor glasdegib benefits AML patients by increasing overall survival in the absence of complete remission (CR), suggesting that the antileukemia activity of glasdegib may be mediated through elimination of LSCs [ 68 – 70 ]. A recent study shows that the activity of Hedgehog pathway is largely independent of Smo and therefore inherently resistant to Smo inhibitors in AML, and hypomethylating agent improves glasdegib sensitivity by increasing the level of Gli-3 repressor and modulation of Gli-1 [ 71 ].…”

Update on glasdegib in acute myeloid leukemia – broadening horizons of Hedgehog pathway inhibitors

“…This significant OS improvement is reflected in a 49 % reduction in the risk of death for patients treated with glasdegib/LDAC, compared to LDAC alone. These data have been refined by treatment-response and exposure-response analyses, also specifying that variability in glasdegib exposures did not impact the risk of death (64). CR was achieved in 17 % (n = 15) and 2.3 % (n = 1) patients in glasdegib/LDAC arm and LDAC arm, respectively.…”

Therapeutic Drug Monitoring of Kinase Inhibitors in Oncology

“…An exposure-toxicity analysis was conducted for creatine kinase increase, but no relationship was observed [ 105 , 106 ]. For glasdegib, no exposure-response relationship was seen for OS and radiological response, but exposure was significantly associated with dysgeusia, muscle spasms, renal toxicity and QTc-time prolongation ( n = 75–272) [ 107 – 109 ] Therapeutic drug monitoring in hedgehog pathway inhibitors could therefore primarily be of valuable in preventing excessive toxicity in patients using glasdegib [ 108 ].…”