Systemic monotherapy with temozolomide (TMZ) or bevacizumab (BEV); two-drug combinations, such as Irinotecan (IRI) and BEV, TMZ and BEV and a three-drug combination with TMZ, IRI and BEV (TIB) have been used in treating patients with progressive high-grade gliomas including glioblastoma. Most patients tolerated these regimens well with well-established sides effects of hypertension, proteinuria, and reversible clinical myelosuppression (CM). However, organ-specific toxicities have never been examined by postmortem studies.
Postmortem tissues (from all major organs) were prospectively collected and examined by standard institution autopsy and brain cutting procedures from 76 decedents, including gliomas (N=68, 44/M, and 24/F) and brain metastases (N=8, 5/M, and 3/F) between 2009 and 2019. Standard hematoxylin and eosin (H&E) were performed on all major organs and brain samples harvested. Electronic microscopic (EM) study was carried on selected subjects kidney samples per standard EM protocol.
Twenty-four glioma subjects were treated with TIB [median: 5.5 (range: 1-25) cycles] at glioma recurrence. Exposure to IRI significantly increased the frequency of CM (p=0.05). No unexpected adverse events were detected clinically or permenant end-organ damage by postmortem examination among subjects who received TIB compared to subjects who received standard of care (SOC) therapies. Among glioma decedents, the most common causes of death (COD) were tumor progression (63.2%, N=43), followed by aspiration pneumonia (48.5%, N=33). No COD was attributed to acute toxicity from TIB. The study also demonstrated that postmortem kidney specimen is unsuitable for studying renal ultrastructural pathological changes due to autolysis.
IRI, but not the extended use of TMZ, significantly increased CM in recurrent glioma patients. There is no permanent organ-specific toxicity among glioma decedents who received prolonged BEV, TMZ or TIB regimen based chemotherapies except expected occasional myelosuppresson. COD are most commonly resulted from glioma tumor progression and aspiration pneumonia.