First-in-Human Phase I Clinical Trial of Pharmacologic Ascorbate Combined with Radiation and Temozolomide for Newly Diagnosed Glioblastoma

Clin Cancer Res. 2019 Nov 15;25(22):6590-6597. doi: 10.1158/1078-0432.CCR-19-0594. Epub 2019 Aug 19.


Purpose: Standard treatment for glioblastoma (GBM) includes surgery, radiation therapy (RT), and temozolomide (TMZ), yielding a median overall survival (OS) of approximately 14 months. Preclinical models suggest that pharmacologic ascorbate (P-AscH-) enhances RT/TMZ antitumor effect in GBM. We evaluated the safety of adding P-AscH- to standard RT/TMZ therapy.

Patients and methods: This first-in-human trial was divided into an RT phase (concurrent RT/TMZ/P-AscH-) and an adjuvant (ADJ) phase (post RT/TMZ/P-AscH- phase). Eight P-AscH- dose cohorts were evaluated in the RT phase until targeted plasma ascorbate levels were achieved (≥20 mmol/L). In the ADJ phase, P-AscH- doses were escalated in each subject at each cycle until plasma concentrations were ≥20 mmol/L. P-AscH- was infused 3 times weekly during the RT phase and 2 times weekly during the ADJ phase continuing for six cycles or until disease progression. Adverse events were quantified by CTCAE (v4.03).

Results: Eleven subjects were evaluable. No dose-limiting toxicities occurred. Observed toxicities were consistent with historical controls. Adverse events related to study drug were dry mouth and chills. Targeted ascorbate plasma levels of 20 mmol/L were achieved in the 87.5 g cohort; diminishing returns were realized in higher dose cohorts. Median progression-free survival (PFS) was 9.4 months and median OS was 18 months. In subjects with undetectable MGMT promoter methylation (n = 8), median PFS was 10 months and median OS was 23 months.

Conclusions: P-AscH-/RT/TMZ is safe with promising clinical outcomes warranting further investigation.

Publication types

  • Clinical Trial, Phase I
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Antineoplastic Agents, Alkylating / administration & dosage
  • Antineoplastic Agents, Alkylating / adverse effects
  • Antineoplastic Agents, Alkylating / therapeutic use*
  • Chemoradiotherapy
  • Combined Modality Therapy
  • Female
  • Glioblastoma / diagnosis
  • Glioblastoma / mortality
  • Glioblastoma / therapy*
  • Humans
  • Kaplan-Meier Estimate
  • Male
  • Middle Aged
  • Neoplasm Staging
  • Radiotherapy* / adverse effects
  • Radiotherapy* / methods
  • Temozolomide / administration & dosage
  • Temozolomide / adverse effects
  • Temozolomide / therapeutic use*
  • Treatment Outcome


  • Antineoplastic Agents, Alkylating
  • Temozolomide