Loven, D., Levavi, H., Sabach, G., Zart, R., Andras, M., Fishman, A., . . . Gadoth, N. (2009). Long-term glutamate supplementation failed to protect against peripheral neurotoxicity of paclitaxel. European Journal of Cancer Care, 18, 78–83.

The focus of the study was to evaluate the role of glutamate supplementation in preventing paclitaxel-induced peripheral neuropathy.

Patients were randomized to receive daily placebo or 500 mg glutamate supplementation beginning on the first day of chemotherapy. Treatment was continued throughout six cycles of chemotherapy and for an additional three weeks. Patients were assessed for neuropathy with serial electro-diagnostic measurements at baseline and at the end of the study.

The total sample consisted of 43 women with a median age of 59 years (range of 35–80 years) who were diagnosed with gynecologic cancers and were receiving paclitaxel.

The study was conducted in multiple outpatient sites throughout Israel.

Phase of care

• Active antitumor treatment

The study had a double-blind, placebo-controlled randomized trial design.

• Various electro-diagnositic measurements were used to assess nerve conduction and sensory conduction velocity.
• The National Cancer Institute's Common Terminology Criteria for Adverse Events (NCI-CTCAE) was used for assessment, as was a 0–3 scale to measure change in symptoms.

An indication of peripheral neuropathic toxicity was lower in patients receiving glutamate, but the difference was not statistically significant. However, significantly lower pain levels were noted in the glutamate group (p = 0.011). No differences were found between groups regarding electro-diagnostic measurements.

The study does not provide strong support for the benefit of glutamate in the prevention of peripheral neuropathy in patients receiving paclitaxel. No firm conclusions can be drawn due to study limitations.

• A small sample size (less than 100).
• The questionable validity and reliability of the three-point assessment scale.
• Findings may not be generalizable to patients receiving other chemotherapeutic agents.
• Of the 67 patients randomized, the consort diagram shows a final sample of 43; however, results are only reported for 38 patients. Actual sample and reasons for withdrawal are not well explained.

The findings suggest that glutamate does not prevent peripheral neuropathy during treatment with paclitaxel. Conclusions are limited due to study deficiencies.