Possible enhancement of vincristine neuropathy by VP-16

Pharmacokinetic evaluation of vincristine for the treatment of lymphoid malignancies

INTRODUCTION

Vincristine is a key agent for the treatment of acute lymphoblastic leukemia (ALL) and other lymphoid malignancies. The strong antineoplastic activity of vincristine has been limited by its pharmacological characteristics.

AREAS COVERED

This paper reviews the role of vincristine in the treatment of lymphoid malignancies. This review summarizes its efficacy and toxicity, and focuses on the pharmacokinetic features of vincristine that affect clinical outcomes.

EXPERT OPINION

As a single agent, vincristine is associated with brief and incomplete responses, but in combination with other agents, vincristine has dramatically improved the outcomes of lymphoid malignancies such as ALL. Vincristine is a key drug of hyper-fractionated cyclophosphamide, vincristine, doxorubicin and dexamethasone, an intensive chemotherapeutic regimen for the treatment of ALL, and of cyclophosphamid, adriamycin, vincristine and prednisone, which has been used extensively in the treatment of patients with aggressive or indolent lymphomas and Richter syndrome. The strong antileukemic activity of vincristine has been limited by its variable and unpredictable pharmacological characteristics, narrow therapeutic index and neurotoxicity profile. These characteristics prompted the development of liposomal vincristine, which has optimized its clinical application. Liposomal vincristine has promising antileukemic activity, and it is approved by the FDA as a single agent for the treatment of relapsed/refractory Philadelphia chromosome-negative ALL.

Olesoxime (TRO19622): A Novel Mitochondrial-Targeted Neuroprotective Compound

Olesoxime (TRO19622) is a novel mitochondrial-targeted neuroprotective compound undergoing a pivotal clinical efficacy study in Amyotrophic Lateral Sclerosis (ALS) and also in development for Spinal Muscular Atrophy (SMA). It belongs to a new family of cholesterol-oximes identified for its survival-promoting activity on purified motor neurons deprived of neurotrophic factors. Olesoxime targets proteins of the outer mitochondrial membrane, concentrates at the mitochondria and prevents permeability transition pore opening mediated by, among other things, oxidative stress. Olesoxime has been shown to exert a potent neuroprotective effect in various in vitro and in vivo models. In particular olesoxime provided significant protection in experimental animal models of motor neuron disorders and more particularly ALS. Olesoxime is orally active, crosses the blood brain barrier, and is well tolerated. Collectively, its pharmacological properties designate olesoxime as a promising drug candidate for motor neuron diseases.

Targeting neuroprotection as an alternative approach to preventing and treating neuropathic pain

Neuropathic pain syndromes arise from dysfunction of the nerve itself, through traumatic or nontraumatic injury. Unlike acute pain syndromes, the pain is long-lasting and does not respond to common analgesic therapies. Drugs that disrupt nerve conduction and transmission or central sensitization, currently the only effective treatments, are only modestly effective for a portion of the patients suffering from neuropathic pain and come with the cost of serious adverse effects. Neurodegeneration, as a reaction to nerve trauma or chronic metabolic or chemical intoxication, appears to be an underlying cause of neuropathic pain. Identifying mechanisms of neurodegeneration and designing neuroprotective therapies is an ambitious goal toward treating or even preventing the development of these disabling disorders.

Dysfunction in multiple primary afferent fiber subtypes revealed by quantitative sensory testing in patients with chronic vincristine-induced pain

Vincristine is one of the frontline chemotherapy drugs for the treatment of numerous lymphoid neoplasias. The main dose-limiting complication of vincristine is the development of painful peripheral neuropathy. Although clinical reports have appeared in the literature detailing the symptoms of vincristine neuropathy, quantitative sensory testing data that might yield insight to dysfunction in subsets of primary afferents are lacking. In this report, pain descriptors and anatomical distributions of sensory abnormalities were collected in each patient. Touch detection threshold, sharpness detection threshold, the thresholds for the detection of skin warming, heat pain, skin cooling, and the perception of cooling-induced pain were measured in patients with chronic vincristine-induced pain in each area of sensory abnormality and in skin perceived as outside the affected areas. Elevated touch detection thresholds were observed both within and outside areas affected by pain and sensory abnormality. Elevated sharpness and warm detection thresholds were noted only in areas affected by pain. These data suggest that chronic vincristine-induced pain is associated with dysfunction in Abeta, Adelta, and C caliber primary afferent fibers. Deficits in Abeta fibers appear to precede and presage deficits in the other fiber types, whereas deficits in Adelta- and C-fiber function appear to be specifically associated with the generation of pain.

Vincristine-induced alterations in Schwann cells of mouse peripheral nerve

The sciatic nerve of C57Bl mice was examined with a transmission electron microscope to study the ultrastructural alterations in Schwann cells following treatment with escalating doses of vincristine. Results indicated that the drug exerts a dose-related effect. Total doses up to 8 micrograms/mouse did not cause any visible damage to Schwann cells. Higher doses induced not only damage to individual cells, but also affected a greater percentage of them. The myelin sheath was the most affected organelle. Schwann cells of myelinated fibers showed greater damage than those of unmyelinated fibers.

Neuromuscular disorders in systemic malignancy and its treatment

Neuromuscular dysfunction in patients with known or suspected malignancy has three basic etiologies: (1) a direct effect of the neoplasm, either by compression or infiltration; (2) a "remote," or paraneoplastic, effect of cancer; or (3) a side effect of anticancer treatment, radiation or chemotherapy. A variety of clinical features or syndromes are due to damage either at the level of the neuron (anterior horn cell or dorsal root ganglion neuron), nerve root(s), brachial or lumbosacral plexus, peripheral nerve (motor, sensory, and/or autonomic), neuromuscular junction, or muscle. A complex clinical picture evolves when dysfunction in due to more than one cause at more than one anatomical site.

Etoposide- and BMY-40481-induced sensory neuropathy in mice

The effects of high toxic doses of the anticancer drugs, etoposide and its phosphate derivative, BMY-40481, on the nervous system of female CD-1 mice were examined by light microscopy (LM) and transmission electron microscopy. Mice were euthanatized 4 wk following a single iv injection of either 0, 50, 100, or 150 mg/kg of BMY-40481 or 44 or 88 mg/kg of etoposide. Mice treated with 100 or 150 mg/kg of BMY-40481 or 88 mg/kg of etoposide had clinical symptomology of progressive ataxia, impaired righting reflex, and splaying and paresis of fore- and hindlimbs at day 8. Similar, dose-related LM changes were observed with both drugs at all doses and consisted of degeneration of dorsal root ganglion cells and axonal degeneration of their distal and proximal processes in peripheral nerves, dorsal spinal roots, and dorsal funiculi of spinal cord. Axonal degeneration was characterized by LM as shrinkage, swelling, and fragmentation of axon cylinders accompanied by secondary demyelination. Degenerative changes in ganglion cell bodies included eccentric nuclei, cytoplasmic vacuolation, central chromatolysis, and peripheral clumping of Nissl's bodies. Ultrastructurally, ganglion cell bodies had focally extensive dilation of the rough endoplasmic reticulum, mitochondrial swelling, increased numbers of phagolysosomes and prominent aggregations of microfilaments (globular filamentous bodies). Ultrastructural axonal changes occurred primarily in large, myelinated fibers and consisted of axonal swelling or loss, thinning of myelin sheaths, and a decrease in the number of organelles. This is the first report of etoposide-related sensory neuropathy in laboratory rats, a model that my be useful for the study of etoposide-related peripheral neuropathy in humans.

Neurotoxicity of antineoplastic agents

PURPOSE

to review the neurotoxicity associated with antineoplastic agents.

METHODS

four hundred articles, abstracts and book chapters were selected for review. One hundred and ninety (articles, book chapters and abstracts) were identified as representative of the important aspects of neurotoxicity to be presented in this review.

RESULTS

in general the dose, schedule and route of administration significantly determine the incidence and outcome of antineoplastic agents neurotoxicity. An updated and detailed review of neurotoxicity is provided with special attention to vinca alkaloids, cisplatin and biologic response modifiers. The neurotoxic side effects of some of the new approaches in cancer therapy and some of the investigational agents are discussed. Guidelines for the prevention and management of this toxicity are presented. In addition, suggestions are made in regard to the preclinical and clinical screening of new agents for neurotoxicity.

CONCLUSION

quality of life issues have become a focal point in many clinical trials. Neurotoxicity associated with antineoplastic therapy clearly has an impact on the short and long term quality of the life of cancer patients. A better understanding of this toxicity requires developing reliable and predictive models to screen new agents prior to their introduction into clinical trials; a more detailed and uniform grading system; and the prospective evaluation of neurotoxicity in clinical trials of new antineoplastic agents.

Peripheral sensory abnormalities in patients with multiple sclerosis

Although multiple sclerosis primarily affects myelin within the central nervous system, both pathologic and physiological studies suggest that mild deficits in peripheral nervous system myelin may be common. To evaluate this question further, we performed near nerve studies on sural nerves of 14 patients with multiple sclerosis. Peak-to-peak amplitude and maximum conduction velocity were normal in 9 of 14 patients, while minimum conduction velocity, or the velocity of the slowest-conducting component of the sensory action potential, was abnormally reduced in 9 patients. In addition, the supernormal period was evaluated for patients and compared with a control sample; multiple sclerosis patients showed a significant reduction in the amplitude of supernormality. Both the reduction in minimum conduction velocity and the alteration in the supernormal period are consistent with a mild defect in peripheral myelin.

Combination high-dose etoposide and vincristine infusion

Following the identification of a synergistic antitumor effect in a murine model, the combination of etoposide and vincristine has been explored in the clinic. Etoposide was given at 4 dose levels (250, 500, 750 or 1,000 mg/m2) with each dose given in 3 equal fractions daily for 3 days. The dose of vincristine was fixed (two 0.75 mg infusions over 22 hours each between doses of etoposide). A total of 26 patients were entered into study and 7, 11, 10 and 5 patients were treated at the 250, 500, 750, and 1,000 mg/m2 dose levels, respectively. Myelosuppression was the principle side effect and Grade 4 WBC toxicity (less than 1,000/mm3) developed in 14%, 27%, 40% and 40%, respectively, of the patients treated at each of these respective dose levels. Life-threatening infections occurred in 0%, 9%, 30% and 60% of the patients at these levels, respectively. Reversal of marrow toxicity was rapid with repeat courses given at 3-week intervals. Non-hematologic toxicity, including neurotoxicity, nausea, vomiting, and mucositis was generally mild when present. Objective responses were observed in 1 patient each with refractory Hodgkin's disease and immunoblastic lymphoma. Prolonged periods of stable disease occurred in 2 patients with adenocarcinoma of the lung and one patient with Hodgkin's disease. The starting dose of etoposide recommended for further trials of this agent in combination with infusion of vincristine is 500 mg/m2 given in fractionated doses; dose escalation should be possible in many patients.

Phase I study of vincristine and escalating doses of etoposide

A phase I trial of vincristine and etoposide was designed following the identification of a potentially synergistic antitumor effect in a murine model. The dose of vincristine was fixed (0.5 mg daily for 3 days). Etoposide was given at 1 of 3 total dose levels (250, 500, or 750 mg/m2) per treatment. Each dose was given in 3 equal fractions and each fraction was given daily for 3 days, i.e., 83.3 mg/m2/d x 3d, 166.7 mg/m2/d x 3d, or 250 mg/m2/d x 3d. A total of 31 patients were entered into study including 10, 18, and 3 patients treated at the 250, 500, and 750 mg/m2 dose levels, respectively. Dose-limiting toxicity occurred at the 750 mg/m2 level, in which Grade 4 myelosuppression developed in all of the patients. Life-threatening gram negative sepsis occurred in two of these patients and both required platelet transfusions. Grade 3-4 WBC toxicity was observed in 9 of 16 (56%) evaluable patients treated at the 500 mg/m2 level, but reversal of toxicity was generally rapid with repeat courses given at 3 week intervals in most patients. Non-hematologic toxicity was negligible. Objective responses were observed in 2 of 4 patients with Hodgkin's disease. The starting dose of etoposide recommended for phase II trials of this agent in combination with vincristine is 500 mg/m2; dose escalation may be possible in some patients.

Infusion of etoposide and vincristine in non-Hodgkin's lymphoma

Infusion of etoposide has previously been evaluated in phase I trials. Vincristine (VCR) given by infusion has been shown in a phase II trial to be active in some cases of non-Hodgkin's lymphoma despite prior exposure to bolus VCR. Infusion of etoposide and the combination of VCR infusion with etoposide (given either as an infusion or bolus) were evaluated in 24 patients with previously treated non-Hodgkin's lymphoma. Five-day infusions of etoposide alone (n = 10), both etoposide and VCR (n = 9), or VCR with bolus etoposide (n = 5) were evaluated. Partial responses were observed in 0, 2 (22%), and 1 (20%) of the patients, respectively. Myelosuppression was the principal toxicity with the 5-day infusions of etoposide alone and with the double infusion combination, but was mild in the VCR infusion coupled with etoposide bolus. Non-hematologic toxicity was mild to moderate in each. For patients with refractory non-Hodgkin's lymphoma, the infusion of etoposide with or without VCR infusion appeared to offer no advantage over bolus administration of etoposide or infusion of VCR alone.

Vincristine neurotoxicity in Charcot-Marie-Tooth syndrome

The case of a patient with Charcot-Marie-Tooth syndrome and diffuse large-cell lymphoma, in whom a severe generalized weakness developed after the intravenous administration of vincristine (2 mg) during combination chemotherapy, is reported. Spontaneous resolution of the severe weakness occurred when teniposide was substituted for vincristine in the chemotherapy regimen.

Amsacrine and etoposide induced paralytic ileus in a patient with acute myelomonocytic leukemia

A 73-year-old man with acute myelomonocytic leukemia developed a severe paralytic ileus after amsacrine and etoposide treatment. The ileus did not respond to treatment with gastric suction and intravenous fluids. Autonomic neuropathy induced by anti-neoplastic drugs may lead to this life-threatening condition.

Cyclic alternating combination chemotherapy for small cell lung cancer

Sixty-two patients with small cell carcinoma of lung received cyclic alternating non-cross-resistant combination chemotherapy. Radiation to the chest was given to all the patients. Patients were given a course of VP16, adriamycin and vincristine (VAV) followed by radiation (3,000 rads) to the chest and then a second course of VAV. Three weeks later, a course of cytoxan, CCNU, and methotrexate (CCM) was given (6 weeks). Subsequently, the treatment was cycled between two courses of VAV (6 weeks) and one course of CCM (6 weeks). Overall objective response rate of 73%, with 45% complete response, was noted. Overall median survival was 50 weeks, with 83 weeks for complete responders. Median survival for patients with regional disease was 58 weeks compared to 40 weeks for extensive disease. All the patients headed for complete response did so prior to receiving CCM. These results were not superior to conventional combination chemotherapy regimens.

Treatment of extensive stage small cell bronchogenic carcinoma. Effects of variation in intensity of induction chemotherapy

Forty-nine consecutive previously untreated patients with extensive stage small cell bronchogenic carcinoma were treated with cyclophosphamide 1,000 mg/m2, doxorubicin 50 mg/m2, etoposide (VP-16-213) 125 mg/m2, and vincristine 1.4 mg/m2 (maximum 2 mg) as induction chemotherapy. Thirty-four patients were given high-intensity therapy, receiving these drugs on both Days 1 and 8 of two or three 21-day induction courses. Fifteen other patients were treated with moderate intensity, receiving these drugs only on Day 1 of two 21-day induction courses. The number and intensity of induction courses were determined by the time of entry into the study. There were 31 complete or partial remissions among the 33 evaluable patients treated with high-intensity therapy (94 percent), including eight complete remissions (24 percent), whereas there were 11 responses (73 percent) including three complete responses (20 percent) among the 15 patients treated with moderate-intensity therapy. There was no marked tendency for the patients in the high-intensity group to have a more favorable response to the induction chemotherapy (p = 0.22), and survival experience was very similar in the two groups (p = 0.92). Overall median survival was 12 months. Within the high-intensity group, there was no significant difference between patients receiving two or three courses of induction therapy with respect to response (p = 0.97) or survival (p = 0.32). There were six induction deaths in the high-intensity induction group (18 percent) and one induction death in the moderate-intensity group (7 percent) (p = 0.59). In addition to the expected hematologic and infectious complications, there were unexpectedly high frequencies of mucositis, reversible congestive heart failure, and severe peripheral neuropathy in patients treated with high-intensity induction. Only two patients, both in the high-intensity group, were alive and free of disease at 24 months. Increasing the intensity of induction chemotherapy with these drugs did not significantly improve response or survival in extensive stage small cell bronchogenic carcinoma.