Glutamine as a neuroprotective agent in high-dose paclitaxel-induced peripheral neuropathy: a clinical and electrophysiologic study.

AIMS: The appearance of peripheral neuropathy is the dose-limiting toxicity in many chemotherapy protocols, and glutamine has been proposed as a potentially neuroprotective agent in patients receiving paclitaxel. MATERIALS AND METHODS: In this non-randomised study, we assessed neurologic signs and symptoms, and changes in nerve-conduction studies in 46 consecutive patients given high-dose paclitaxel either with (n=17) or without (n=29) glutamine. Neurological assessments and electrodiagnostic studies were carried out at baseline and at least 2 weeks (median 32 days) after treatment. RESULTS: Patients who received glutamine developed significantly less weakness (P = 0.02), less loss of vibratory sensation (P = 0.04) and less toe numbness (P = 0.004) than controls. The per cent change in the compound motor action potential (CMAP) and sensory nerve action potential (SNAP) amplitudes after paclitaxel treatment was lower in the glutamine group, but this finding was not statistically significant in these small groups. CONCLUSIONS: In this study, serial neurologic assessment of patient symptoms and signs seemed to be a better indicator of a possible glutamine effect than sensory- or motor-nerve-conduction studies. Prospective randomised trials are needed to clarify the effect of glutamine on paclitaxel and other types of chemotherapy-induced neuropathy.

The pharmacokinetics and pharmacodynamics of high-dose paclitaxel monotherapy (825 mg/m2 continuous infusion over 24 h) with hematopoietic support in women with metastatic breast cancer.

PURPOSE: We evaluated the pharmacokinetics and pharmacodynamics of high-dose paclitaxel (HDP) monotherapy (825 mg/m2 continuous infusion over 24 h) with peripheral blood progenitor cell (PBPC) and G-CSF support in 17 women with metastatic breast cancer. METHODS: Pharmacokinetic and pharmacodynamic data were collected in 17 women entered in a phase II trial of sequential HDP, and high-dose melphalan and cyclophosphamide/thiotepa/carboplatin. RESULTS: The maximal plasma concentration (Cmax), area under the plasma concentration time curve (AUC), apparent clearance (Clapp), duration of plasma concentration above 0.05 microM (t > 0.05 microM) for paclitaxel were (means SD): 9.11 +/- 7.45 microM, 145 +/- 88 microM x h, 8.06 +/- 2.90 l/h per m2 and 82.4 +/- 31.2 h, respectively. There was a significant correlation between the plasma paclitaxel concentration at 1 h (r2 = 0.87), 12 h (r2 = 0.85) and 23 h (r2 =0.92) and the AUC (P < 0.0001). Duration of neutropenia was brief (median 3 days, range 0-5 days) and neutrophil recovery occurred earlier (median 6 days, range 0-7 days) than could be attributed to infused PBPC. Median nadir count for platelets was 66 x 10(9)/l (range 13-160 x 10(9)/l). Pharmacodynamic analysis showed no correlation between pharmacokinetic parameters (Cmax, AUC, t > 0.05 microM) and time to neutropenic nadir, duration of neutropenia, platelet count nadir and grades of neuropathy or mucositis. In ten patients in whom detailed neurologic and nerve conduction studies were performed, linear regression analysis showed a significant correlation between pre- and post-HDP treatment total neuropathy scores (r2 = 0.46, P = 0.03). CONCLUSIONS: HDP (825 mg/m2 continuous infusion over 24 h) did not appear to be myeloablative. The degree of neurotoxicity subsequent to HDP was associated with the degree of baseline neuropathy but was not predictable from pharmacokinetic parameters.

Nevus of Ota and leptomeningeal melanocytic lesions.

Two patients with congenital nevus of Ota developed intracranial malignant melanocytic tumors. One had a localized tumor that resembled a melanocytoma, but the other had a more highly malignant tumor that diffusely seeded the leptomeninges. There are 10 prior cases in the world literature. These cases are contrasted with the other disorders in which melanotic skin lesions are associated with CNS melanocytic tumors, including neurocutaneous melanosis, cellular blue nevus, and metastatic malignant melanoma. Each disorder tends to involve particular sites of the CNS. The nevus of Ota can be considered a neurocristopathy and, rarely, may give rise to malignant CNS lesions.