An intracerebral microdialysis study to determine the neuropharmacokinetics of eribulin in patients with metastatic or primary brain tumors.

Purpose: Eribulin is an inhibitor of microtubule dynamics. It is not as highly protein bound as the taxanes and is less vulnerable to extrusion by P-glycoprotein in the blood-brain barrier (BBB). These features predict that eribulin could play an active role in managing brain tumors. Indeed, the small amount of published clinical data indicates eribulin may have some efficacy against breast cancer brain metastases. To better understand the potential of eribulin for treating brain tumors, we performed an intracerebral microdialysis study to determine the neuropharmacokinetics of eribulin in cancer patients undergoing tumor resection.

Methods: After tumor removal, two microdialysis catheters were inserted into peritumoral brain tissue. Approximately 24 h after surgery, a single dose of eribulin 1.4 mg/m² was administered intravenously. Dialysate samples were collected continuously for 72 h, with plasma samples collected in parallel. Eribulin concentrations were analyzed by tandem mass spectrometry.

Results: Dialysate samples from 12 intracerebral microdialysis catheters placed in 7 study participants were included in the analysis. A statistically significant difference was observed between eribulin concentrations in brain tissue where BBB was disrupted versus intact, with a difference in mean maximum concentrations on log₂ scale of 3.37 (std err = 0.59, p-value = 0.005). Nonetheless, overall brain to plasma ratios of eribulin only ranged from 0.13 to 1.99%.

Conclusion: Although we could detect higher concentrations of eribulin in brain tissue where BBB was disrupted, intracerebral eribulin levels were not sufficient to predict eribulin would have consistent clinically meaningful activity against tumors in the brain.

Clinicaltrials:

Gov identifier: NCT02338037 (January 9, 2015).