Dataset Information

Pharmacokinetics, safety, and tolerability of olaparib and temozolomide for recurrent glioblastoma: results of the phase I OPARATIC trial.

ABSTRACT:

Background

The poly(ADP-ribose) polymerase (PARP) inhibitor olaparib potentiated radiation and temozolomide (TMZ) chemotherapy in preclinical glioblastoma models but brain penetration was poor. Clinically, PARP inhibitors exacerbate the hematological side effects of TMZ. The OPARATIC trial was conducted to measure penetration of recurrent glioblastoma by olaparib and assess the safety and tolerability of its combination with TMZ.

Methods

Preclinical pharmacokinetic studies evaluated olaparib tissue distribution in rats and tumor-bearing mice. Adult patients with recurrent glioblastoma received various doses and schedules of olaparib and low-dose TMZ in a 3?+?3 design. Suitable patients received olaparib prior to neurosurgical resection; olaparib concentrations in plasma, tumor core and tumor margin specimens were measured by mass spectrometry. A dose expansion cohort tested tolerability and efficacy of the recommended phase II dose (RP2D). Radiosensitizing effects of olaparib were measured by clonogenic survival in glioblastoma cell lines.

Results

Olaparib was a substrate for multidrug resistance protein 1 and showed no brain penetration in rats but was detected in orthotopic glioblastoma xenografts. Clinically, olaparib was detected in 71/71 tumor core specimens (27 patients; median, 496 nM) and 21/21 tumor margin specimens (9 patients; median, 512.3 nM). Olaparib exacerbated TMZ-related hematological toxicity, necessitating intermittent dosing. RP2D was olaparib 150 mg (3 days/week) with TMZ 75 mg/m2 daily for 42 days. Fourteen (36%) of 39 evaluable patients were progression free at 6 months. Olaparib radiosensitized 6 glioblastoma cell lines at clinically relevant concentrations of 100 and 500 nM.

Conclusion

Olaparib reliably penetrates recurrent glioblastoma at radiosensitizing concentrations, supporting further clinical development and highlighting the need for better preclinical models.

SUBMITTER: Hanna C

PROVIDER: S-EPMC7746945 | biostudies-literature | 2020 Dec

REPOSITORIES: biostudies-literature

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Publications

Pharmacokinetics, safety, and tolerability of olaparib and temozolomide for recurrent glioblastoma: results of the phase I OPARATIC trial.

Hanna Catherine C Kurian Kathreena M KM Williams Karin K Watts Colin C Jackson Alan A Carruthers Ross R Strathdee Karen K Cruickshank Garth G Dunn Laurence L Erridge Sara S Godfrey Lisa L Jefferies Sarah S McBain Catherine C Sleigh Rebecca R McCormick Alex A Pittman Marc M Halford Sarah S Chalmers Anthony J AJ

Neuro-oncology 20201201 12

<h4>Background</h4>The poly(ADP-ribose) polymerase (PARP) inhibitor olaparib potentiated radiation and temozolomide (TMZ) chemotherapy in preclinical glioblastoma models but brain penetration was poor. Clinically, PARP inhibitors exacerbate the hematological side effects of TMZ. The OPARATIC trial was conducted to measure penetration of recurrent glioblastoma by olaparib and assess the safety and tolerability of its combination with TMZ.<h4>Methods</h4>Preclinical pharmacokinetic studies evaluat ...[more]

PMID: 32347934

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Project description:BACKGROUND: Preclinical studies have demonstrated that pharmacological mobilization and recruitment of endogenous bone marrow stem cells and immunoregulatory cells by a combination of plerixafor and low-dose tacrolimus (MRG-001) improves wound healing, promotes tissue regeneration and prevents allograft rejection. This first‐in‐human phase I dose‐escalation study evaluates the safety, tolerability, pharmacokinetics and pharmacodynamics of MRG-001, a novel fixed-dose combination drug. METHODS: In this Phase 1, double‐blind, randomized, placebo-controlled study, multiple ascending dose (MAD) cohorts are randomized to receive MRG-001 containing up to 0.02 mL/kg (plerixafor 24 mg/mL and tacrolimus 0.5 mg/mL) or saline placebo, subcutaneously every other day (SC, QAD) for 5 days (ClinicalTrials.gov: NCT04646603)The primary outcome is safety and tolerability. Safety and functional assessments are performed throughout the study. Blood samples are collected to evaluate systemic exposure. Fluorescence-activated cell sorting analysis and RNA expression of peripheral blood mononuclear cells (PBMCs) are used to evaluate the pharmacodynamics. RESULTS: Fourteen subjects received MRG-001 and 7 received a placebo. MRG-001 is safe and well-tolerated over the selected dose range. No deaths or severe adverse events are reported. There are no clinically significant laboratory changes after MRG-001 administration, apart from the predicted generalized leukocytosis. The intermediate dose group (0.01 mL/kg) showed the most significant white blood cell mobilization over time and increased by 2-4 fold from baseline and returned to baseline levels prior to the next injection. Circulating immune cells including FOXP3+ regulatory T cells and hematopoietic stem cells (CD45IntCD34+) increased significantly after MRG-001 injection. PBMC RNA sequencing and gene set enrichment analysis revealeds 31 down-regulated pathways in the intermediate dose MRG-001 group compared to no changes in the placebo group. CONCLUSION: MRG-001 is safe and well-tolerated across the full dose ranges tested. MRG-001 may be a clinically useful therapy for immunoregulation and tissue regeneration. A Phase II trial to treat severely and critically ill COVID-19 patients with MRG-001 has been initiated (NCT04646603) and a second phase II trial will explore the potential of MRG-001 to accelerate wound healing (NCT05844527),

Dataset Information

Pharmacokinetics, safety, and tolerability of olaparib and temozolomide for recurrent glioblastoma: results of the phase I OPARATIC trial.

Background

Methods

Results

Conclusion

Publications

Pharmacokinetics, safety, and tolerability of olaparib and temozolomide for recurrent glioblastoma: results of the phase I OPARATIC trial.

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