Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0031117 (peripheral neuropathy)
 10,577 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Although paclitaxel (TAXOL) appears to be one of the most promising antineoplastic agents of the last decade, with demonstrated activity in advanced and refractory ovarian, breast, lung, and head and neck cancers, most clinical oncologists have had little experience with the agent. This is largely the result of the initially limited supply of paclitaxel and other obstacles encountered during early clinical development that restricted the drug's availability to a few investigational centers. Although a high incidence of major hypersensitivity reactions due to the Cremophor EL vehicle used in formulation disrupted and almost terminated the clinical development of paclitaxel, hypersensitivity reactions are no longer a serious problem consequent to the advent of effective premedication regimens and longer administration schemes. Instead, neutropenia is the principal toxicity of paclitaxel. At clinically relevant doses, absolute neutrophil count nadirs are severely depressed in most patients. The duration of severe neutropenia, however, is usually brief; treatment delays for unresolved hematologic toxicity are rare, and absolute neutrophil count nadirs are constant with repetitive dosing, suggesting that neutropenia is not cumulative. Asymptomatic sinus bradycardia has occurred in up to 29% of patients in phase II trials, and other cardiac disturbances, including atrioventricular conduction and bundle branch blocks, ventricular tachycardia, and possible ischemic manifestations, have been reported in approximately 3% of patients. Cardiac disturbances have primarily been noted in studies that used cardiac monitoring to more effectively detect and manage major hypersensitivity reactions. Although sinus bradycardia and conduction blocks appear to represent true toxicities, ventricular tachycardia and ischemic manifestations, which have largely been observed in patients with preexisting cardiac disease, may not be due to paclitaxel. In view of the lack of clinical significance of the cardiac effects and their infrequent occurrence, cardiac monitoring during paclitaxel is not recommended for patients without cardiac risk factors. However, until precise risk factors can be defined, patients with a significant antecedent cardiac history are generally not considered to be good candidates for paclitaxel therapy. Neurotoxicity, characterized principally by peripheral neurosensory manifestations, has generally been of mild to moderate severity, even in heavily pretreated patients at paclitaxel doses < or = 200 mg/m2. However, some patients have developed a severe sensory-motor polyneuropathy at higher doses of paclitaxel (given as a single agent or in combination with cisplatin). Patients with an antecedent peripheral neuropathy or coexisting medical illnesses associated with peripheral neuropathy (such as diabetes mellitus and substantial prior alcohol use) appear to be especially prone to developing peripheral neuropathy.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Clinical toxicities encountered with paclitaxel (Taxol). 810 12

Cremophor EL (CrEL) is a formulation vehicle used for various poorly-water soluble drugs, including the anticancer agent paclitaxel (Taxol). In contrast to earlier reports, CrEL is not an inert vehicle, but exerts a range of biological effects, some of which have important clinical implications. Its use has been associated with severe anaphylactoid hypersensitivity reactions, hyperlipidaemia, abnormal lipoprotein patterns, aggregation of erythrocytes and peripheral neuropathy. The pharmacokinetic behaviour of CrEL is dose-independent, although its clearance is highly influenced by duration of the infusion. This is particularly important since CrEL can affect the disposition of various drugs by changing the unbound drug concentration through micellar encapsulation. In addition, it has been shown that CrEL, as an integral component of paclitaxel chemotherapy, modifies the toxicity profile of certain anticancer agents given concomitantly, by mechanisms other than kinetic interference. A clear understanding of the biological and pharmacological role of CrEL is essential to help oncologists avoid side-effects associated with the use of paclitaxel or other agents using this vehicle. With the present development of various new anticancer agents, it is recommended that alternative formulation approaches should be pursued to allow a better control of the toxicity of the treatment and the pharmacological interactions related to the use of CrEL.
 ...
PMID:Cremophor EL: the drawbacks and advantages of vehicle selection for drug formulation. 1152 83

The non-ionic surfactants Cremophor EL (CrEL; polyoxyethyleneglycerol triricinoleate 35) and polysorbate 80 (Tween) 80; polyoxyethylene-sorbitan-20-monooleate) are widely used as drug formulation vehicles, including for the taxane anticancer agents paclitaxel and docetaxel. A wealth of recent experimental data has indicated that both solubilisers are biologically and pharmacologically active compounds, and their use as drug formulation vehicles has been implicated in clinically important adverse effects, including acute hypersensitivity reactions and peripheral neuropathy.CrEL and Tween 80 have also been demonstrated to influence the disposition of solubilised drugs that are administered intravenously. The overall resulting effect is a highly increased systemic drug exposure and a simultaneously decreased clearance, leading to alteration in the pharmacodynamic characteristics of the solubilised drug. Kinetic experiments revealed that this effect is primarily caused by reduced cellular uptake of the drug from large spherical micellar-like structures with a highly hydrophobic interior, which act as the principal carrier of circulating drug. Within the central blood compartment, this results in a profound alteration of drug accumulation in erythrocytes, thereby reducing the free drug fraction available for cellular partitioning and influencing drug distribution as well as elimination routes. The existence of CrEL and Tween 80 in blood as large polar micelles has also raised additional complexities in the case of combination chemotherapy regimens with taxanes, such that the disposition of several coadministered drugs, including anthracyclines and epipodophyllotoxins, is significantly altered. In contrast to the enhancing effects of Tween 80, addition of CrEL to the formulation of oral drug preparations seems to result in significantly diminished drug uptake and reduced circulating concentrations. The drawbacks presented by the presence of CrEL or Tween 80 in drug formulations have instigated extensive research to develop alternative delivery forms. Currently, several strategies are in progress to develop Tween 80- and CrEL-free formulations of docetaxel and paclitaxel, which are based on pharmaceutical (e.g. albumin nanoparticles, emulsions and liposomes), chemical (e.g. polyglutamates, analogues and prodrugs), or biological (e.g. oral drug administration) strategies. These continued investigations should eventually lead to more rational and selective chemotherapeutic treatment.
 ...
PMID:Pharmacological effects of formulation vehicles : implications for cancer chemotherapy. 1284 27

Cumulative peripheral neuropathy (PNP) still remains a limitation to optimal treatment with paclitaxel (PAC), especially in more dose-dense schedules. This primary sensory PNP may affect the majority of patients after administration of certain cumulative dosages of PAC, while the exact mechanisms of PAC-induced PNP are not known. While a number of preclinical models revealed its vehicle Cremophor EL (CrEL) to be mainly responsible for ganglionopathy, axonopathy and demyelination, clinical data also supports a strong and independent effect of PAC itself, which is most likely based on disturbances in the microtubules in perikaryons, axons and glia cells. Indeed, clinical trials of CrEL-free formulations of PAC still report grade III neurotoxicity as dose-limiting. As treatment options of PAC-induced PNP are rare the use of specific scoring systems for screening purposes is strongly encouraged. In this report we review and discuss the pathogenesis, incidence, risk factors, diagnosis, pharmacodynamics and treatment options for PAC-induced PNP.
 ...
PMID:Peripheral neuropathy: a persisting challenge in paclitaxel-based regimes. 1629 11

Over the past two decades, the taxanes have played a significant role in the treatment of various malignancies. However, the poor solubility of these compounds necessitates the inclusion of surfactant vehicles in their commercial formulations. Cremophor EL and polysorbate 80 have long comprised the standard solvent system for paclitaxel and docetaxel, respectively. A number of pharmacologic and biologic effects related to both of these drug formulations have been described, including clinically relevant acute hypersensitivity reactions and peripheral neuropathy. In addition, these solvents affect the disposition of intravenously administered solubilized drugs and leach plasticizers from polyvinylchloride infusion sets. A number of strategies to develop formulations of surfactant-free taxanes have been developed. They include albumin nanoparticles, polyglutamates, taxane analogs and prodrugs, emulsions, and lipsomes. An overview of these novel formulations of taxanes, their mechanisms of action, pharmacokinetics, dose and administration, adverse effects, and clinical efficacy will be discussed.
 ...
PMID:Novel formulations of taxanes: a review. Old wine in a new bottle? 1636 60

Taxanes are standard treatment for metastatic breast cancer; however, the solvents used as vehicles in these formulations cause severe toxicities. The FDA recently approved a solvent-free formulation of paclitaxel for the treatment of metastatic breast cancer that utilises 130-nanometer albumin-bound (nab) technology (Abraxane; nab-paclitaxel) to circumvent the requirement for solvents. nab-Paclitaxel utilises the natural properties of albumin to reversibly bind paclitaxel, transport it across the endothelial cell and concentrate it in areas of tumour. The proposed mechanism of drug delivery involves, in part, glycoprotein 60-mediated endothelial cell transcytosis of paclitaxel-bound albumin and accumulation in the area of tumour by albumin binding to SPARC (secreted protein, acidic and rich in cysteine). Clinical studies have shown that nab-paclitaxel is significantly more effective than paclitaxel formulated as Cremophor EL (CrEL, Taxol, CrEL-paclitaxel), with almost double the response rate, increased time to disease progression and increased survival in second-line patients. The absence of CrEL from the formulation is associated with decreased neutropenia and rapid improvement of peripheral neuropathy with nab-paclitaxel, compared with CrEL-paclitaxel. For these reasons, nab-paclitaxel can be administered using higher doses of paclitaxel than that achievable with CrEL-paclitaxel, with shorter infusion duration and without the requirement for corticosteroid and antihistamine premedication to reduce the risk of solvent-mediated hypersensitivity reactions. Taken together, these studies have demonstrated that nab technology has increased the therapeutic index of paclitaxel compared with the conventional, solvent-based formulation.
 ...
PMID:Albumin-bound paclitaxel: a next-generation taxane. 1672 14

Genexol-PM is a novel Cremophor EL-free polymeric micelle formulation of paclitaxel. This single arm, multicenter phase II study was designed to evaluate the efficacy and safety of Genexol-PM in patients with histologically confirmed metastatic breast cancer (MBC). Forty-one women received Genexol-PM by intravenous infusion at 300 mg/m2 over 3 h every 3 weeks without premedication until disease progression or intolerability. A total of 331 chemotherapy cycles were administered, with a median of 8 cycles per patient (range, 1-16). Overall response rate was 58.5% (95% CI: 43.5-72.3) with 5 complete responses and 19 partial responses. Thirty-seven patients who received Genexol-PM as a first-line therapy for their metastatic disease showed a response rate of 59.5% (95% CI: 43.5-73.7), and two responses were reported in four patients treated in the second-line setting for their metastatic disease. The median time to progression (TTP) for all patients was 9.0 months (range, 1.0-17.0+ months). Grade 3 non-hematologic toxicities included sensory peripheral neuropathy (51.2%), and myalgia (2.4%). Eight patients (19.5%) experienced hypersensitivity reactions, with grade 3 in two patients. Hematologic toxicities were grade 3 and 4 neutropenia (51.2 and 17.1%, respectively), and grade 1 and 2 thrombocytopenia (22.0%). Notably, no febrile neutropenia was observed. Genexol-PM appears a promising new paclitaxel in view of significant efficacies. Further trials with different dosing schedules, durations of delivery, or in combination with other drugs are warranted.
 ...
PMID:Multicenter phase II trial of Genexol-PM, a Cremophor-free, polymeric micelle formulation of paclitaxel, in patients with metastatic breast cancer. 1747 88

Activation of cannabinoid CB(2) receptors suppresses neuropathic pain induced by traumatic nerve injury. The present studies were conducted to evaluate the efficacy of cannabinoid CB(2) receptor activation in suppressing painful peripheral neuropathy evoked by chemotherapeutic treatment with the antitumor agent paclitaxel. Rats received paclitaxel (2 mg/kg i.p./day) on 4 alternate days to induce mechanical hypersensitivity (mechanical allodynia). Mechanical allodynia was defined as a lowering of the threshold for paw withdrawal to stimulation of the plantar hind paw surface with an electronic von Frey stimulator. Mechanical allodynia developed in paclitaxel-treated animals relative to groups receiving the Cremophor EL/ethanol/saline vehicle at the same times. Two structurally distinct cannabinoid CB(2) agonists, the aminoalkylindole (R,S)-AM1241 [(R,S)-(2-iodo-5-nitrophenyl)-[1-((1-methyl-piperidin-2-yl)methyl)-1H-indol-3-yl]-methanone] and the cannabilactone AM1714 (1,9-dihydroxy-3-(1',1'-dimethylheptyl)-6H-benzo[c]chromene-6-one), produced a dose-related suppression of established paclitaxel-evoked mechanical allodynia after systemic administration. Pretreatment with the CB(2) antagonist SR144528 [5-(4-chloro-3-methylphenyl)-1-(4-methylbenzyl)-N-(1,3,3-trimethylbicyclo[2.2.1]heptan-2-yl)-1H-pyrazole-3-carboxamide], but not the CB(1) antagonist SR141716 [5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-N-(piperidin-1-yl)-1H-pyrazole-3-carboxamide], blocked the antiallodynic effects of both (R,S)-AM1241 and AM1714. Moreover, (R)-AM1241, but not (S)-AM1241, suppressed paclitaxel-evoked mechanical allodynia relative to either vehicle treatment or preinjection thresholds, consistent with mediation by CB(2). Administration of either the CB(1) or CB(2) antagonist alone failed to alter paclitaxel-evoked mechanical allodynia. Moreover, (R,S)-AM1241 did not alter paw withdrawal thresholds in rats that received the Cremophor EL vehicle in lieu of paclitaxel, whereas AM1714 induced a modest antinociceptive effect. Our data suggest that cannabinoid CB(2) receptors may be important therapeutic targets for the treatment of chemotherapy-evoked neuropathy.
 ...
PMID:Selective activation of cannabinoid CB2 receptors suppresses neuropathic nociception induced by treatment with the chemotherapeutic agent paclitaxel in rats. 1866 90

Paclitaxel, a microtubule stabilizer, is an effective agent for treating cancer of the breast, ovary, head and neck, and lung. Because paclitaxel is insoluble in water, it is formulated with the micelle-forming Cremophor EL. Neurologic toxicity is well described with both the drug and this carrier, with most toxicities manifesting as peripheral neuropathy, motor neuropathy, autonomic neuropathy, and myopathy. Toxic effects on the central nervous system, such as seizures or encephalopathy, have been rarely reported; however, the seizures reported were closely related to the time of infusion. We describe a 41-year-old woman with no history of seizures who was treated with paclitaxel for breast cancer. Four days after the drug was infused, she developed a generalized tonic-clonic seizure that could not be attributed to other causes. The patient was treated with phenytoin and was able to complete her adjuvant chemotherapy with nab-paclitaxel without further events. Her condition was neurologically stable without phenytoin for the next 6 months. Use of the Naranjo adverse drug reaction probability scale indicated a possible association (score of 3) between the delayed seizure and paclitaxel or its solvent, Cremophor EL. Clinicians should be aware of the potential for seizure activity in patients who receive paclitaxel formulated with Cremophor EL.
 ...
PMID:Delayed seizure associated with paclitaxel-Cremophor el in a patient with early-stage breast cancer. 1963 53

Natural diterpenoid taxanes and their semisynthetic analogues have already made an indelible mark in the chemotherapeutic world for treating various kinds of malignancies. However, due to the absence of any functional groups which could be ionized by pH alteration or which may participate in salt formation, these taxanes, exhibit low solubility. Parenteral administration of taxanes with solubilising agents such as Cremophor EL and Polysorbate 80 results in undesirable side effects like hypersensitivity reactions, myelosuppression and peripheral neuropathy. Nanoengineered drug delivery systems like nanoemulsions, nanocrystals, dendrimers, micelles, selfnanoemulsifying systems, liposomes, solid-lipid nanoparticles and biodegradable polymeric nanoparticles, in this regard, tend to surmount these ostensible challenges, when administered orally. The bare taxanes encounter several inadequacies, namely poor aqueous solubility, structural instability in physiological fluids, p-glycoprotein recognition, hepatic first-pass effect, gastrointestinal permeability, and Cytochrome P450 enzymatic metabolism, etc. In addition, nanoscaled oral delivery improves drug encapsulation, thus facilitating diffusion through intestinal epithelium, modification of pharmacokinetic and tissue distribution profile of the drug, eventually resulting in flexibility of dosing schedules, prevention of discomfort of the injection and hospitalization, and improved patient convenience. The current review paper endeavors to provide a bird's eye view on the significant headway made on orally-administered nanosystems of taxanes and their analogues through patent applications published till date since its discovery.
...
PMID:The Sojourn from Parenteral to Oral Taxanes using Nanocarrier Systems: A Patent Review. 2642 3


1 2 Next >>