Pharmacodynamics of non-break weekly paclitaxel (Taxol) and pharmacokinetics of Cremophor-EL vehicle: results of a dose-escalation study

Risk Factors for Chemotherapy-Induced Peripheral Neuropathy Caused by Nanoparticle Albumin-Bound Paclitaxel in Advanced Breast Cancer

Breast cancer (BC) is one of the most common malignancies affecting women and the leading cause of related mortality worldwide. An estimated 2260000 new cases of BC were diagnosed in 2020, which have seriously threatened the health. Paclitaxel (PTX), a natural product isolated from the bark of the pacific yew, has been found to be effective in treating advanced BC. Chemotherapy-induced peripheral neuropathy (CIPN), which refers to the damage to the peripheral nerves caused by exposure to a neurotoxic chemotherapeutic agent, is a common side effect affecting the patients undergoing PTX chemotherapy. Significant research efforts are needed to identify the various risk factors associated with CIPN. Here, a univariate analysis in BC patients with nanonab-PTX treatment was performed. The rate of CIPN in BC patients with albumin-bound paclitaxel (nab-PTX) for more than four weeks was significantly higher than that of patients with chemotherapy for less than four weeks. Moreover, the rate of CIPN in BC patients receiving nab-PTX first-line chemotherapy was remarkably higher than that in BC patients receiving paclitaxel as a sequence scheme. Taken together, chemotherapy cycles and the priority of nab-PTX-based chemotherapy can be considered the potential risk factors for CIPN induced by nab-PTX.

Pegylated liposomal doxorubicin-related palmar-plantar erythrodysesthesia: a literature review of pharmaceutical and clinical aspects

OBJECTIVES

The rate of dermal toxicity has been shown to increase in patients receiving pegylated liposomal doxorubicin (PLD), particularly palmar-plantar erythrodysesthesia (PPE). However, it is difficult to diagnose and treat PLD-related PPE due to its delayed dermal performance, unclear pathogenetic mechanism, and the lack of specific preventive measures. The aim of this study was to provide potential management strategies for PPE associated with PLD.

METHODS

The current article reviews the available data regarding the pharmacological and clinical aspects of PLD, including the formulation and pharmacokinetics of PLD, dose and schedule contribution to PPE, concomitant drugs affecting skin toxicity of PLD, the pathogenesis of PPE, and preventive measures and treatment of PLD-related PPE.

RESULTS

The long circulation structure of polyethylene glycol liposomes may be one of the reasons for PPE. PLD has radically different pharmacokinetic characteristics, including prolonged blood circulation time, decreased body distribution volume, and slow clearance. Altering the schedules and doses of PLD or combining it with platinum compounds can optimise clinical efficacy and minimise the occurrence of PPE. Doses of 150-200 mg of pyridoxine daily have been widely used for the prevention and treatment of PPE. Regional cooling and plasma filtration have been used for PPE prophylaxis.

CONCLUSIONS

To date, the mechanism of PPE induced by PLD remains unclear, and no complete preventive medication has been established. Further research and prospective randomised studies are needed to understand the management options in PLD-related PPE.

Comparing Paclitaxel-Carboplatin with Paclitaxel-Cisplatin as the Front-Line Chemotherapy for Patients with FIGO IIIC Serous-Type Tubo-Ovarian Cancer

The use of weekly chemotherapy for the treatment of patients with advanced-stage serous-type epithelial Tubo-ovarian cancer (ETOC), and primary peritoneal serous carcinoma (PPSC) is acceptable as the front-line postoperative chemotherapy after primary cytoreductive surgery (PCS). The main component of dose-dense chemotherapy is weekly paclitaxel (80 mg/m²), but it would be interesting to know what is the difference between combination of triweekly cisplatin (20 mg/m²) or triweekly carboplatin (carboplatin area under the curve 5-7 mg/mL per min [AUC 5-7]) in the dose-dense paclitaxel regimen. Therefore, we compared the outcomes of women with Gynecology and Obstetrics (FIGO) stage IIIC ETOC and PPSC treated with PCS and a subsequent combination of dose-dense weekly paclitaxel and triweekly cisplatin (paclitaxel–cisplatin) or triweekly carboplatin using AUC 5 (paclitaxel–carboplatin). Between January 2010 and December 2016, 40 women with International Federation of Gynecology and Obstetrics (FIGO) stage IIIC EOC, FTC, or PPSC were enrolled, including 18 treated with paclitaxel–cisplatin and the remaining 22 treated with paclitaxel–carboplatin. There were no statistically significant differences in disease characteristics of patients between two groups. Outcomes in paclitaxel–cisplatin group seemed to be little better than those in paclitaxel–carboplatin (median progression-free survival [PFS] 30 versus 25 months as well as median overall survival [OS] 58.5 versus 55.0 months); however, neither reached a statistically significant difference. In terms of adverse events (AEs), patients in paclitaxel–carboplatin group had more AEs, with a higher risk of neutropenia and grade 3/4 neutropenia, and the need for a longer period to complete the front-line chemotherapy, and the latter was associated with worse outcome for patients. We found that a period between the first-time chemotherapy to the last dose (6 cycles) of chemotherapy >21 weeks was associated with a worse prognosis in patients compared to that ≤21 weeks, with hazard ratio (HR) of 81.24 for PFS and 9.57 for OS. As predicted, suboptimal debulking surgery (>1 cm) also contributed to a worse outcome than optimal debulking surgery (≤1 cm) with HR of 14.38 for PFS and 11.83 for OS. Based on the aforementioned findings, both regimens were feasible and effective, but maximal efforts should be made to achieve optimal debulking surgery and following the on-schedule administration of dose-dense weekly paclitaxel plus triweekly platinum compounds. Randomized trials validating the findings are warranted.

Co-targeting the tumor endothelium and P-selectin-expressing glioblastoma cells leads to a remarkable therapeutic outcome

Glioblastoma is a highly aggressive brain tumor. Current standard-of-care results in a marginal therapeutic outcome, partly due to acquirement of resistance and insufficient blood-brain barrier (BBB) penetration of chemotherapeutics. To circumvent these limitations, we conjugated the chemotherapy paclitaxel (PTX) to a dendritic polyglycerol sulfate (dPGS) nanocarrier. dPGS is able to cross the BBB, bind to P/L-selectins and accumulate selectively in intracranial tumors. We show that dPGS has dual targeting properties, as we found that P-selectin is not only expressed on tumor endothelium but also on glioblastoma cells. We delivered dPGS-PTX in combination with a peptidomimetic of the anti-angiogenic protein thrombospondin-1 (TSP-1 PM). This combination resulted in a remarkable synergistic anticancer effect on intracranial human and murine glioblastoma via induction of Fas and Fas-L, with no side effects compared to free PTX or temozolomide. This study shows that our unique therapeutic approach offers a viable alternative for the treatment of glioblastoma.

Pharmacokinetic and toxicity considerations for the use of anthracyclines in ovarian cancer treatment

INTRODUCTION

Safe and effective treatments are needed for ovarian cancer. While there are many drugs currently available, there has recently been a renewed novel interest in the use of anthracyclines.

AREAS COVERED

This review summarizes the available evidence on pharmacokinetic (PK) and toxicology implications of anthracyclines and pegylated liposomal doxorubicin (PLD) in the clinical management of women with epithelial ovarian cancer. This article consists of material obtained via Medline, PubMed and EMBASE literature searches, up to September 2010.

EXPERT OPINION

PLD is a liposomal formulation of doxorubicin (DXR), with a distinct pharmacokinetic profile, characterized by extended circulation time and a reduced clearance and volume of distribution with respect to the free drug. PLD is effective and well tolerated in relapsed ovarian cancer. The toxicity profile of PLD is characterized by dose-limiting mucosal and cutaneous toxicities, mild myelosuppression and decreased cardiotoxicity compared to free DXR. The good response rate, toxicity profile and pharmacokinetic profile of PLD suggest that PLD could be an option in first-line and second-line treatment in ovarian cancer; especially in those who had experienced taxane-induced toxicity or had a poor performance status.

Vasodilatation in the rat dorsal hindpaw induced by activation of sensory neurons is reduced by paclitaxel

Peripheral neuropathy is a major side effect following treatment with the cancer chemotherapeutic drug paclitaxel. Whether paclitaxel-induced peripheral neuropathy is secondary to altered function of small diameter sensory neurons remains controversial. To ascertain whether the function of the small diameter sensory neurons was altered following systemic administration of paclitaxel, we injected male Sprague Dawley rats with 1mg/kg paclitaxel every other day for a total of four doses and examined vasodilatation in the hindpaw at day 14 as an indirect measure of calcitonin gene related peptide (CGRP) release. In paclitaxel-treated rats, the vasodilatation induced by either intradermal injection of capsaicin into the hindpaw or electrical stimulation of the sciatic nerve was significantly attenuated in comparison to vehicle-injected animals. Paclitaxel treatment, however, did not affect direct vasodilatation induced by intradermal injection of methacholine or CGRP, demonstrating that the blood vessels' ability to dilate was intact. Paclitaxel treatment did not alter the compound action potentials or conduction velocity of C-fibers. The stimulated release of CGRP from the central terminals in the spinal cord was not altered in paclitaxel-injected animals. These results suggest that paclitaxel affects the peripheral endings of sensory neurons to alter transmitter release, and this may contribute to the symptoms seen in neuropathy.

Delayed seizure associated with paclitaxel-Cremophor el in a patient with early-stage breast cancer

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.

Cell cycle checkpoint models for cellular pharmacology of paclitaxel and platinum drugs

A pharmacokinetic-pharmacodynamic mathematical model is developed for cellular pharmacology of chemotherapeutic drugs for which the decisive step towards cell death occurs at a point in the cell cycle, presumably corresponding to a cell cycle checkpoint. For each cell, the model assumes a threshold level of some intracellular species at that checkpoint, beyond which the cell dies. The threshold level is assumed to have a log-normal distribution in the cell population. The kinetics of formation of the lethal intracellular species depends on the drug, and on the cellular pharmacokinetics and binding kinetics of the cell. Specific models are developed for paclitaxel and for platinum drugs (cisplatin, oxaliplatin and carboplatin). In the case of paclitaxel, two separate mechanisms of cell death necessitate a model that accounts for two checkpoints, with different intracellular species. The model was tested on a number of in vitro cytotoxicity data sets for these drugs, and found overall to give significantly better fits than previously proposed cellular pharmacodynamic models. It provides an explanation for the asymptotic convergence of dose-response curves as exposure time becomes long.

Peripheral neuropathy: A persisting challenge in paclitaxel-based regimes

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.

Weekly paclitaxel combined with pegylated liposomal doxorubicin (Caelyx™) given every 4 weeks: dose-finding and pharmacokinetic study in patients with advanced solid tumors

BACKGROUND

We aimed to define the maximum tolerated dose (MTD) and characterize the toxicity of the combination of pegylated liposomal doxorubicin (PLD; Caelyx trade mark ) and weekly paclitaxel (wPTX), and to investigate pharmacokinetics of PLD in this combination.

METHODS

A phase I study was performed with an initial dose of 50 mg/m(2) wPTX and 30 mg/m(2) PLD. The paclitaxel dose was escalated in increments of 10 mg/m(2) and PLD in increments of 5 mg/m(2) until the MTD was reached. The pharmacokinetics of PLD were studied at the highest achieved dose levels.

RESULTS

Forty-four cancer patients were enrolled. The MTD was 30/90 and 35/80 mg/m(2) for PLD/wPTX. Dose-limiting toxicities included treatment delay for neutropenia grade 3, febrile neutropenia, palmar-plantar erythrodysesthesia and deep venous thrombosis. Toxicity below the MTD was mild: skin toxicity grade 1-2 developed at high cumulative doses and vascular thrombotic events occurred in two patients with predisposing factors. No cardiotoxicity or clinically relevant peripheral neuropathy was seen. Nausea/vomiting and alopecia were negligible. Three complete responses and nine partial responses were documented among 34 evaluable cases. PLD plasma concentrations were evaluated in seven patients treated at subMTD. Paclitaxel produced a median 53.5% increase of PLD area under the concentration curve (range 4.4%-219%).

CONCLUSIONS

The combination of PLD/wPTX constitutes an active chemotherapy regimen with mild toxicity that merits investigation in phase II at 30/80 or 35/70 mg/m(2). Patients should be monitored for a potentially increased risk of thromboembolic events.

Pharmacological effects of formulation vehicles : implications for cancer chemotherapy

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.

Weekly administration of paclitaxel: theoretical and clinical basis

The rationale for weekly administration of paclitaxel, which acts on microtubules to arrest mitosis, is that more frequent delivery of moderate doses may achieve greater efficacy than standard doses every 3 weeks, through more sustained exposure of dividing tumor cells to its cytotoxic effects. This dose-dense approach to treatment may inhibit tumor regrowth between cycles and limit the emergence of malignant cell populations resistant to chemotherapy. More frequent exposure to paclitaxel may also enhance its apoptotic and antiangiogenic effects. Paclitaxel activity is considered to be independent of p53 status, in contrast to anticancer drugs that produce lesions on DNA, which achieve a better response if p53 is functional. Weekly therapy also has advantages in terms of improving paclitaxel therapeutic index. Clinical studies show that weekly paclitaxel is effective and that toxicity is acceptable. The response rates of single-agent paclitaxel varied from 21 to 86% in breast cancer, from 20% to 65% in ovarian cancer and from 30% to 56% in non-small cell lung cancer.