Altered clearance of unbound paclitaxel in elderly patients with metastatic breast cancer

Key Considerations for the Treatment of Advanced Breast Cancer in Older Adults: An Expert Consensus of the Canadian Treatment Landscape

The prevalence of breast cancer amongst older adults in Canada is increasing. This patient population faces unique challenges in the management of breast cancer, as older adults often have distinct biological, psychosocial, and treatment-related considerations. This paper presents an expert consensus of the Canadian treatment landscape, focusing on key considerations for optimizing selection of systemic therapy for advanced breast cancer in older adults. This paper aims to provide evidence-based recommendations and practical guidance for healthcare professionals involved in the care of older adults with breast cancer. By recognizing and addressing the specific needs of older adults, healthcare providers can optimize treatment outcomes and improve the overall quality of care for this population.

Does Older Age Lead to Higher Risk for Neutropenia in Patients Treated with Paclitaxel?

PURPOSE

There is ongoing concern regarding increased toxicity from paclitaxel in elderly patients, particularly of severe neutropenia. Yet, data so far is controversial and this concern is not supported by a clinically relevant age-dependent difference in pharmacokinetics (PK) of paclitaxel. This study assessed whether age is associated with increased risk for paclitaxel-induced neutropenia.

METHODS

Paclitaxel plasma concentration-time data, pooled from multiple different studies, was combined with available respective neutrophil count data during the first treatment cycle. Paclitaxel pharmacokinetic-pharmacodynamic (PK-PD) data was modeled using a non-linear mixed effects approach and a semiphysiological neutropenia model, where systemic paclitaxel exposure was linked to reduced proliferation of neutrophils. The impact of age was evaluated on relevant variables in the model, using a significance threshold of p < 0.005.

RESULTS

Paclitaxel PK-PD data was evaluated from 300 patients, with a median age of 65 years (range 23-84 years), containing 116 patients ≥70 years (39%). First cycle neutrophil counts were adequately described by a threshold effect model of paclitaxel on the proliferation rate of neutrophils. Age as a continuous or dichotomous variable (≥70 versus <70 years) did not significantly impact sensitivity of the bone marrow to paclitaxel nor the average maturation time of neutrophils (both p > 0.005), causing a decline in the respective interindividual variability of <1%.

CONCLUSION

Results from this large retrospective patient cohort do not suggest elderly patients to be at an increased risk of developing paclitaxel-associated neutropenia during the first treatment cycle. Reflexive dose reductions of paclitaxel in elderly patients are unlikely to improve the risk of severe neutropenia and may be deleterious.

Impact of Older Age on the Exposure of Paclitaxel: a Population Pharmacokinetic Study

PURPOSE

Limited available data suggest that older patients are more prone to develop paclitaxel-induced toxicity than their younger peers. It remains unclear whether this is related to age-dependent pharmacokinetics (PK) of paclitaxel. Primary objective of this study was to determine the influence of older age on the PK of paclitaxel.

METHODS

PK data of patients aged ≥70 years who received paclitaxel intravenously at the Netherlands Cancer Institute (NKI) and the Radboud University Medical Center between September 2012 and May 2017 were collected. These prospectively collected data were pooled with previously published databases from multiple clinical trials conducted at the NKI and Erasmus MC Cancer Institute. A previously developed 3-compartment population PK model with saturable distribution and elimination was used to describe paclitaxel plasma concentration-time data. Hereafter, influence of age on paclitaxel PK was assessed in a previously established full covariate model.

RESULTS

In total, paclitaxel PK data from 684 patients were available, consisting of 166 patients ≥70 years (24%). Median age of the cohort was 61 years (range 18 to 84 years). The impact of age, either treated as a continuous or dichotomous covariate (<70 versus ≥70 years), on the elimination of paclitaxel was only marginal but statistically significant (both p < 0.001 with no clinically relevant decrease in interindividual variability). For a typical patient, maximal elimination capacity decreased by only 5% for a 10-year increment of age.

CONCLUSION

In this extensive multi-center dataset, which included a considerable number of older patients, older age had no clinically relevant impact on paclitaxel PK.

Patients carrying CYP2C8*3 have shorter systemic paclitaxel exposure

AIM

First, evaluate if patients carrying putatively diminished activity CYP2C8 genotype have longer paclitaxel exposure (e.g., time above threshold concentration of 0.05 μM [T_{c >0.05}]). Second, screen additional pharmacogenes for associations with T_{c >0.05}. Methods: Pharmacogene panel genotypes were translated into genetic phenotypes for associations with T_{c >0.05} (n = 58).

RESULTS

Patients with predicted low-activity CYP2C8 had shorter T_{c >0.05} after adjustment for age, body surface area and race (9.65 vs 11.03 hrs, β = 5.47, p = 0.02). This association was attributed to CYP2C8*3 (p = 0.006), not CYP2C8*4 (p = 0.58). Patients with predicted low-activity SLCO1B1 had longer T_{c >0.05} (12.12 vs 10.15 hrs, β = 0.85, p = 0.012).

CONCLUSION

Contrary to previous publications, CYP2C8*3 may confer increased paclitaxel metabolic activity. SLCO1B1 and CYP2C8 genotype may explain some paclitaxel pharmacokinetic variability.

Age and the Risk of Paclitaxel-Induced Neuropathy in Women with Early-Stage Breast Cancer (Alliance A151411): Results from 1,881 Patients from Cancer and Leukemia Group B (CALGB) 40101

PURPOSE

A few previous studies report a direct relationship between older age and chemotherapy-induced neuropathy. This study further evaluated this adverse event's age-based risk.

METHODS

CALGB 40101 investigated adjuvant paclitaxel (80 mg/m² once per week or 175 mg/m² every 2 weeks) in patients with breast cancer and served as a platform for the current study that investigated age-based differences in neuropathy. Grade 2 or worse neuropathy, as per Common Terminology Criteria for Adverse Events version 4, was the primary endpoint; patients were assessed at baseline, every 6 months for 2 years, and then annually for 15 years.

RESULTS

Among these 1,881 patients, 230 were 65 years of age or older, 556 were 55-64 years, and 1,095 were younger than 55; 1,226 neuropathy events (commonly grade 1 or 2) were reported in 65% of the cohort. The number of grade 2 or worse events was 63 (27%), 155 (28%), and 266 (24%) within respective age groups (p = .14). In univariate analysis, only motor neuropathy had a higher age-based incidence: 19 (8%), 43 (8%), and 60 (5%), respectively (p = .04); in multivariate analyses, this association was no longer statistically significant. Other endpoints, such as time to onset of neuropathy (time from trial enrollment to neuropathy development) and time to improvement (time from maximal grade sensory neuropathy to a one-category improvement), showed no statistically significant age-based differences. In contrast, obesity was associated with neuropathy, and every 2-week paclitaxel was associated with trends toward neuropathy.

CONCLUSION

Although paclitaxel-induced neuropathy is common, older age is not an independent risk factor. Clinical trial identification number. NCT00041119 (CALGB 40101).

IMPLICATIONS FOR PRACTICE

Age alone is not an independent risk factor for paclitaxel-induced neuropathy.

Phase 1 study of veliparib with carboplatin and weekly paclitaxel in Japanese patients with newly diagnosed ovarian cancer

This phase 1, open-label, dose-escalation study was conducted to determine the safety, tolerability, pharmacokinetics and preliminary efficacy of veliparib with carboplatin and weekly paclitaxel in Japanese women with newly diagnosed, advanced ovarian cancer. Patients received veliparib at 100 or 150 mg b.i.d. on days 1-21 with carboplatin (area under the concentration-time curve 6 mg/mL•min) on day 1 and paclitaxel 80 mg/m² on days 1, 8 and 15 every 3 weeks for up to 6 21-day cycles. Dose escalation followed a 3 + 3 design to determine dose-limiting toxicities, maximum tolerated dose and the recommended phase 2 dose. Nine patients (median age 62 [range 27-72] years) received a median of 5 (range 3-6) cycles of treatment (3 at 100 mg, 6 at 150 mg). There were no dose-limiting toxicities. The most common adverse events of any grade were neutropenia (100%), alopecia (89%), peripheral sensory neuropathy (78%), and anemia, nausea and malaise (67% each). Grade 3 or 4 adverse events were associated with myelosuppression. Pharmacokinetics of carboplatin/paclitaxel were similar at both veliparib doses. Response, assessed in five patients, was partial in four and complete in one (objective response rate 100%). The response could not be assessed in four patients who had no measurable disease at baseline. The recommended phase 2 dose of veliparib, when combined with carboplatin/paclitaxel, is 150 mg b.i.d. Findings from this phase 1 trial demonstrate the tolerability and safety of veliparib with carboplatin/paclitaxel, a regimen with potential clinical benefit in Japanese women with ovarian cancer.

Pharmacokinetics of Chemotherapy in the Older Patient

Background

The number of individuals aged 65 years and older is growing rapidly, and the majority of cancers are diagnosed in this age group. Age-related changes in physiology can affect chemotherapy pharmacokinetics and pharmacodynamics in older patients.

Methods

We review the literature regarding the impact of age on the pharmacokinetics of commonly used chemotherapy drugs and discuss age-related changes in physiology and pharmacology that can affect chemotherapy tolerance in older patients.

Results

The data on age-related changes in chemotherapy pharmacokinetics are conflicting. While a few studies report age-related differences in chemotherapy pharmacokinetics, most found no significant difference or subtle differences in pharmacokinetics with aging. A difference in pharmacodynamics was commonly seen, however, with older patients at increased risk of myelosuppression and toxicity from age-related decline in organ function. The majority of these studies were performed in a small cohort of patients, thus limiting the generalizability of these results.

Conclusions

Additional studies are needed to address the pharmacokinetics and pharmacodynamics of cancer therapies in the older patient. Multicenter pharmacokinetic studies of adequate sample size, which include a thorough evaluation of physiologic factors and geriatric assessment parameters, would provide further insight into the factors affecting treatment tolerance. These studies would also help to guide appropriate chemotherapy dosing and interventions in order to maximize efficacy and minimize toxicity in the older patient.

Tolerance to Chemotherapy in Elderly Patients with Cancer

Background

Due to demographic changes, the number of elderly people with cancer will increase in the next decades. In the past, elderly patients with cancer were often excluded from clinical trials. Chronological age has been considered a risk factor for increased toxicity and reduced tolerance to chemotherapy.

Methods

We present a review on toxicity of chemotherapy and factors associated with toxicity in elderly patients with cancer, and we discuss chemotherapeutic agents and treatment options in treating this patient population.

Results

Age is a risk factor for increased toxicity to chemotherapy and decreased tolerance. However, few trials have been reported with adjustment for age-associated changes such as impairment of functional status and increased comorbidity, which also show an independent association with increased toxicity. Published data may include several biases, such as referral and publication bias.

Conclusions

Decision making in elderly cancer patients should be based on the results of a geriatric assessment. Patients with few or no limitations should be treated as younger patients are treated. Data with a high level of evidence are unavailable for patients showing moderate or severe limitations in a geriatric assessment.

Targeted chemotherapy with nanoparticle albumin-bound paclitaxel (nab-paclitaxel) in metastatic breast cancer: which benefit for which patients?

The therapeutic goals in metastatic breast cancer (MBC) remain palliative in nature, aimed at controlling symptoms, improving or maintaining quality of life and prolonging survival. The advent of new drugs and new formulations of standard agents has led to better outcomes in patients with advanced or metastatic disease. These developments have also allowed a tailored therapeutic approach, in which the molecular biology of the tumour, the treatment history, and patient attitudes are taken into account in the decision-making process. Targeting drug delivery to the tumour is a promising mean of increasing the therapeutic index of highly active agents such as the taxanes, and nanoparticle albumin-bound paclitaxel (nab-paclitaxel), the first nanotechnology-based drug developed in cancer treatment, is one such advance. Data from randomized trials support the efficacy of single-agent nab-paclitaxel as first-line and further treatment lines in MBC at the registered 3-weekly schedule of 260 mg/m(2), but emerging evidence suggests its activity as a weekly regimen or combined with other agents in various clinical scenarios. Thus, nab-paclitaxel seems to offer flexibility in terms of dosing schedules, allowing physicians to tailor the dose according to different clinical situations. This paper reviews the clinical trial background for nab-paclitaxel in MBC, focusing on specific 'difficult-to-treat' patient populations, such as taxane-pretreated or elderly women, as well as those with triple-negative, HER2-positive and poor-prognostic-factors disease. Moving beyond evidence-based information, 'real life' available experiences are also discussed with the aim of providing an update for daily clinical practice.

Effect of age on drug metabolism in women with breast cancer

INTRODUCTION

The aging of the population will increase the number of breast cancer patients requiring treatment in both the adjuvant and metastatic setting. Hormones, chemotherapy and targeted drugs all have a role in treatment. Older patients have been underrepresented in clinical trials making evidence-based decisions difficult. The increase in comorbidity and aging, polypharmacy and changes in function make pharmacotherapy decisions more complicated. Knowledge of the issues is critical in the prescribing of effective and safe therapy. There are factors associated with advancing age that can result in pharmacokinetic and pharmacodynamic variations in processing of hormonal agents, chemotherapy and targeted drugs.

AREAS COVERED

A review of the literature pertaining to pharmacokinetic changes in aging in breast cancer was untaken. Studies are reviewed involving single agents and some combinations.

EXPERT OPINION

Older patients should be considered for standard therapies. Their specific problems need to be evaluated by geriatric-specific assessment including functional status, end organ dysfunction and polypharmacy. There are few instances for age-related changes in pharmacokinetics and when present are usually not clinically significant. When changes are present, they are often the result of comorbidity, drug interactions and drug scheduling issues. The older patients may be more sensitive to certain toxicities such as cardiac toxicity, neuropathy and myelosuppression.

Pharmacokinetics of Selected Anticancer Drugs in Elderly Cancer Patients: Focus on Breast Cancer

Background: Elderly patients receiving anticancer drugs may have an increased risk to develop treatment-related toxicities compared to their younger peers. However, a potential pharmacokinetic (PK) basis for this increased risk has not consistently been established yet. Therefore, the objective of this study was to systematically review the influence of age on the PK of anticancer agents frequently administered to elderly breast cancer patients. Methods: A literature search was performed using the PubMed electronic database, Summary of Product Characteristics (SmPC) and available drug approval reviews, as published by EMA and FDA. Publications that describe age-related PK profiles of selected anticancer drugs against breast cancer, excluding endocrine compounds, were selected and included. Results: This review presents an overview of the available data that describe the influence of increasing age on the PK of selected anticancer drugs used for the treatment of breast cancer. Conclusions: Selected published data revealed differences in the effect and magnitude of increasing age on the PK of several anticancer drugs. There may be clinically-relevant, age-related PK differences for anthracyclines and platina agents. In the majority of cases, age is not a good surrogate marker for anticancer drug PK, and the physiological state of the individual patient may better be approached by looking at organ function, Charlson Comorbidity Score or geriatric functional assessment.

Taxanes in the elderly patient with metastatic breast cancer

More than 40% of all breast cancer cases are diagnosed in patients aged ≥65 years, accounting for an ever-increasing disease burden in the elderly. Historically, however, this growing population of breast cancer patients has been underrepresented in clinical trials, resulting in a paucity of data that clinicians can reference in making treatment decisions for their older patients. A consequence may be the undertreatment of elderly patients, who have the highest incidence of breast cancer. However, subgroup analyses of elderly patients in multiple early-Phase (I or II) studies and a handful of small studies with elderly-specific populations have suggested that older patients may experience similar benefit from cancer therapy as younger patients with otherwise similar baseline characteristics. Although steps should be taken to avoid undertreating older patients, a balance must be achieved to avoid overtreatment. Guidelines have been released detailing recommendations for the treatment of elderly breast cancer patients, including a discussion of various geriatric assessments that might aid physicians in selecting patients appropriate for recommended treatment options. Chemotherapy remains a key component of treatment regimens for many older patients. However, the benefit of some agents may be limited by tolerability issues. Taxanes, one of the most established classes of chemotherapy for breast cancer, are known to be highly active and efficacious and to have well-characterized safety profiles. This review discusses factors that influence treatment choices for elderly patients with metastatic breast cancer, and then focuses on clinical data for taxanes in this patient population.

Pharmacokinetics, dynamics and toxicity of docetaxel: Why the Japanese dose differs from the Western dose

Docetaxel (Taxotere®) has been one of the most important chemotherapeutic drugs for cancer treatment since 1996. Although a large number of clinical studies have been conducted in various cancer fields, there is a discrepancy in the standard dose between Japan and Western countries. This article reviews the pharmacokinetic, pharmacodynamic and toxicological profiles of docetaxel, and explains why there exists an ethnic difference in dose, and further discusses which direction we should go forward to solve this problem. The original recommended dose was 100 mg/m² every 3 weeks in US and European populations, while a Japanese phase I study suggested the recommended dose as 60 mg/m² every 3 weeks. A prospective population pharmacokinetic analysis of docetaxel conducted in both the USA/Europe and Japan, indicated an absence of ethnic difference in the pharmacokinetics. Both analyses demonstrated that docetaxel clearance is related to α1-acid glycoprotein level, hepatic function, age and body surface area. The relationship was observed between increasing docetaxel dose and increased tumor response rates across the dose range of 60 to 100 mg/m². The area under the serum concentration time curve (AUC) of docetaxel at the first cycle was significantly related to time to progression. Hematological toxicities were well correlated with the AUC of docetaxel, and severe hematological toxicities were more frequently observed in Japanese patients treated with 60 mg/m², compared to the US/European patients treated with 75–100 mg/m² dose. The Japanese population seems more susceptible to the toxicity of docetaxel. A docetaxel dose of 75 mg/m² is now standard not only in global trials but also in recent Japanese trials. Although the optimal dose of docetaxel is still unclear, we need to continue to seek the appropriate dose of docetaxel depending on patient status and the goals of chemotherapy.

Age-related changes in nanoparticle albumin-bound paclitaxel pharmacokinetics and pharmacodynamics: influence of chronological versus functional age

PURPOSE

This study evaluated age-related changes in pharmacokinetic and pharmacodynamic parameters of nanoparticle albumin-bound paclitaxel (nab-paclitaxel) in patients with metastatic breast cancer.

METHODS

Forty patients received nab-paclitaxel (100 mg/m(2) weekly for 3 weeks followed by a 1-week break) as first- or second-line chemotherapy. Blood samples were collected for analysis, and response was assessed every two cycles. Planned statistical analyses included linear regression to examine the relationship between age and pharmacokinetic variables (ln clearance [CL] and ln area under the curve [AUC]) and two-sided two-sample t tests to evaluate age differences in pharmacodynamic variables. The association between chemotherapy toxicity risk scores and pharmacokinetic and pharmacodynamic variables including grade ≥ 3 toxicity were examined post hoc.

RESULTS

Of 40 patients enrolled, 39 (98%) were evaluable (mean age: 60 years; range: 30-81 years). A partial response was achieved in 31%, and 38% had stable disease. There was a borderline positive association between age and 24-hour ln AUC (slope = 0.011; SE = 0.006; p = .055). Grade 3 toxicity was experienced by 26% (8% hematologic, 18% nonhematologic). There were no differences in age based on the presence of grade 3 toxicity (p = .75), dose reductions (p = .38), or dose omissions (p = .15). A significant association was noted between chemotherapy toxicity risk score category and presence of grade 3 toxicity (toxicity rate by risk score category: low, 5 of 30 patients; medium, 3 of 6 patients; high, 2 of 3 patients; p = .041).

CONCLUSION

A borderline significant relationship exists between age and 24-hour AUC, but no differences were noted for pharmacodynamic variables (grade 3 toxicity, dose reductions, or dose omissions) based on age. There is an association between toxicity risk score and grade ≥ 3 chemotherapy toxicity and pharmacokinetic variables. The treatment is well tolerated across all age groups.

Personalizing medicine in geriatric oncology

Minimizing toxicity while maximizing efficacy is a common goal in the treatment of any condition but its importance is underscored in the discipline of oncology because of the serious nature of many chemotherapeutic toxicities and the risk of cancer recurrence or disease progression. The challenge of achieving an optimal therapeutic index is especially augmented in the elderly population because of age-related metabolism changes and interacting concurrent medications. Additional factors, such as germline mutations in drug-metabolizing enzymes and other pharmacogenomic alterations, may have more pronounced effects in elderly patients, given their predisposition to altered pharmacokinetics and pharmacodynamics with resulting increased risk of toxicity. Examples of the possible interplay of these factors will be discussed using tamoxifen, paclitaxel, codeine, and fluorouracil as starting points. Limited participation of the elderly in many cancer trials, especially trials assessing drug exposure, makes much knowledge on the interaction of these patient and environmental factors speculative in nature but presents an opportunity for future research to achieve better optimization of chemotherapeutic agents in the elderly.

The impact of medication therapy management in older oncology patients

PURPOSE

This project aimed to identify common drug-related problems (DRP) among elderly cancer patients, to determine the effectiveness of medication therapy management (MTM) service in resolving DRP, to determine the clinical significance of pharmacist interventions, and to determine patients' satisfaction level of MTM service.

METHOD

Elderly cancer patients (age ≥65) who were at least on one chronic medication would be eligible for the MTM service. Any DRP that was detected would be recorded and steps to resolve it were taken. Pre- and post-service patient satisfaction surveys (PSS) were conducted before and after MTM. All interventions performed by MTM pharmacists were subjected to independent evaluation by a panel of three judges.

RESULTS

One hundred eighteen patients received at least one session of MTM. We identified and attempted to resolve 361 DRPs, and the most common DRPs were drug interactions (117 cases, 32.4 %), adverse effects (114 cases, 31.6 %), and non-adherence (48 cases, 13.3 %). Forty-four interventions were performed by pharmacists and forty cases (91 %) were accepted by physicians. Almost two third of these interventions were deemed significant (or higher) by the judges. Seventy-two patients completed PSS. There was statistically significant improvement in patients' satisfaction level after the service was provided.

CONCLUSION

MTM is an important platform in identifying and managing DRPs. Patients are generally satisfied with MTM services.

A Phase I clinical trial of the combination of imatinib and paclitaxel in patients with advanced or metastatic solid tumors refractory to standard therapy

PURPOSE

Pre-clinical data suggest that combining imatinib with traditional cytotoxic chemotherapy may improve imatinib efficacy. We conducted a Phase I study of imatinib in combination with paclitaxel in patients with advanced or metastatic solid tumors.

METHODS

Patients were accrued to the study in a standard 3 + 3 design. Patients were restaged every two cycles, and those with stable disease (SD), or better, continued study treatment without interruption. Maximally tolerated doses (MTDs) and pharmacokinetic profiles of combination imatinib and paclitaxel were assessed.

RESULTS

Fifty-eight patients were enrolled, including 40 in the Phase I dose escalation portion. Alternating dose escalation of imatinib and paclitaxel on a 28-day cycle resulted in MTDs of 800 mg imatinib daily, on days 1-4, 8-11, 15-18, and 22-25, and 100 mg/m(2) paclitaxel weekly, on days 3, 10, and 17. Two expansion cohorts, comprising 10 breast cancer patients and 8 patients with soft-tissue sarcomas, were enrolled at the MTDs. The most common adverse events were flu-like symptoms (64 %) and nausea/vomiting (71 %). The most common Grade 3/4 toxicities were neutropenia (26 %), flu-like symptoms (12 %), and pain (12 %). There were no relevant differences in the pharmacokinetic profiles of either drug when given in combination compared with alone. Thirty-eight subjects were evaluable for response, 18 (47.4 %) of whom experienced clinical benefit. Five patients (13.2 %) had a partial response (PR) and 13 patients (34.2 %) had SD; the average time to progression in those with clinical benefit was 17 weeks (range: 7-28 weeks).

CONCLUSIONS

This combination of imatinib and paclitaxel was reasonably safe and tolerable, and demonstrated evidence of anti-tumor activity. Further exploration in disease-specific Phase II trials is warranted.

Injectable in situ forming controlled release implant composed of a poly-ether-ester-carbonate and applications in the field of chemotherapy

Polymeric controlled delivery systems hold great promise in the field of modern medicine. Such technology has already been converted into commercially viable products in a myriad of fields. Chemotherapy is an example of such an area where constant efficacious levels of drug can greatly enhance clinical outcomes. The key to designing such therapies is the preparation of the proper delivery system. To this end, a series of bioresorbable polyether-ester-carbonate copolymers have been developed, which when combined with a diluent, are capable injection into the body and consistently forming a drug delivery depot. The study delineated here aimed at producing a more effective treatment of a common drug, paclitaxel, using the polymeric carrier. The polymer carrier system exhibited controlled release of paclitaxel both in vitro and in vivo. Drug concentrations were analyzed by high performance liquid chromatography and apoptotic activity was confirmed through flow cytometry. Relevant success was exhibited by the regression of tumor size following a multiple injection treatment regimen in a murine xenograft model. This multiple injection treatment shows promising results when compared to the traditional paclitaxel paradigm of a single injection for a period of 3 weeks.

Appropriate chemotherapy dosing for obese adult patients with cancer: American Society of Clinical Oncology clinical practice guideline

PURPOSE

To provide recommendations for appropriate cytotoxic chemotherapy dosing for obese adult patients with cancer.

METHODS

The American Society of Clinical Oncology convened a Panel of experts in medical and gynecologic oncology, clinical pharmacology, pharmacokinetics and pharmacogenetics, and biostatistics and a patient representative. MEDLINE searches identified studies published in English between 1996 and 2010, and a systematic review of the literature was conducted. A majority of studies involved breast, ovarian, colon, and lung cancers. This guideline does not address dosing for novel targeted agents.

RESULTS

Practice pattern studies demonstrate that up to 40% of obese patients receive limited chemotherapy doses that are not based on actual body weight. Concerns about toxicity or overdosing in obese patients with cancer, based on the use of actual body weight, are unfounded.

RECOMMENDATIONS

The Panel recommends that full weight-based cytotoxic chemotherapy doses be used to treat obese patients with cancer, particularly when the goal of treatment is cure. There is no evidence that short- or long-term toxicity is increased among obese patients receiving full weight-based doses. Most data indicate that myelosuppression is the same or less pronounced among the obese than the non-obese who are administered full weight-based doses. Clinicians should respond to all treatment-related toxicities in obese patients in the same ways they do for non-obese patients. The use of fixed-dose chemotherapy is rarely justified, but the Panel does recommend fixed dosing for a few select agents. The Panel recommends further research into the role of pharmacokinetics and pharmacogenetics to guide appropriate dosing of obese patients with cancer.

Weekly nab-paclitaxel is safe and effective in ≥65 years old patients with metastatic breast cancer: a post-hoc analysis

PURPOSE

This post-hoc analysis of 2 studies investigated the safety and efficacy of weekly and every-3-week (q3w) nanoparticle albumin-bound paclitaxel (nab-paclitaxel) in older patients with metastatic breast cancer (MBC) compared with q3w solvent-based paclitaxel and docetaxel.

RESULTS

Patients≥65 years (median: 69) were analyzed. In phase 2 (n=52), overall response rates (ORR) for weekly nab-paclitaxel were 60-64% vs 22% for q3w nab-paclitaxel and 32% for docetaxel. In phase 3 (n=62), ORRs were 27% for q3w nab-paclitaxel and 19% for solvent-based paclitaxel. In phase 2, median progression-free survival (PFS) was 18.9 months for 150 mg/m2 weekly nab-paclitaxel vs 8.5-13.8 months for all other regimens. In phase 3, median PFS for q3w nab-paclitaxel and solvent-based paclitaxel were 5.6 months and 3.5 months, respectively. Weekly nab-paclitaxel resulted in less serious adverse events compared with all other regimens.

CONCLUSIONS

Weekly nab-paclitaxel was safe and more efficacious compared with the q3w schedule and with solvent-based taxanes in older patients with MBC.

Chemotherapy treatment for older women with metastatic breast cancer: what is the evidence?

While the over-representation of the elderly in the breast cancer population is projected to dramatically increase within the next two decades, data on chemotherapy for elderly patients with metastatic breast carcinoma (MBC) remain very limited. The aim of the present study is to investigate whether elderly patients included in clinical studies for MBC are representative of the population seen during usual clinical practice. Firstly, a review of the literature was performed identifying 39 publications about chemotherapy for MBC focusing on elderly patients and we examined patient characteristics in each of these publications. Comparison of the age distribution of patients included in these studies with that of a large cohort of consecutive MBC patients aged 65years who received chemotherapy in our institution over the last ten years (n=573) indicated that trials tend to include relatively younger patients. Furthermore, criteria to assess external validity of the results are seldom reported. Possible ways to improve the applicability of results such as increasing the minimum age for inclusion and the use of CGA are proposed.

Major clinical research advances in gynecologic cancer in 2010

This review summarizes 11 major clinical research advances in gynecologic oncology in 2010. For ovarian cancer, bevacizumab as a leading molecular targeted agent, pegylated liposomal doxorubicin in recurrent disease, the role of neoadjuvant chemotherapy in an advanced setting, an effective screening method, and ARID1A mutations as a clue to the origin of clear cell carcinoma are mentioned. For cervical cancer, confirmation of the efficacy and the introduction of a self collection method of the human papillomavirus (HPV) test, and the association between the HPV vaccine and miscarriage are examined. For endometrial cancer, the superiority of laparoscopy in staging operation, the role of vaginal brachytherapy in an adjuvant setting, and the effect of para-aortic lymph node dissection are reviewed. In addition, the trend of geriatric oncology and chemotherapy in carcinosarcomas is also assessed.

Taxanes in the elderly: can we gain as much and be less toxic?

Taxanes are very effective agents in several types of cancer. However, their activity is counterbalanced by side effects that could represent a limitation of their use in older cancer patients. This review aims at evaluating whether or not there are data supporting a tailored use of standard taxanes i.e. docetaxel and paclitaxel in elderly patients with the aim to increase their therapeutic index. In addition, recent data on the role of nanoparticle albumine-bound paclitaxel in breast cancer are discussed in this paper.

Anticancer drug therapy in the older cancer patient: pharmacology and polypharmacy

OPINION STATEMENT

Older patients currently are the largest group of oncology patients and their numbers will continue to expand. There has been minimal participation of older patients in clinical trials. This has resulted in a lack of data to make high-level evidence-based decisions with regard to chemotherapy. There has now been a number of clinical trials which have given information with regard to age-related changes and the spectrum of toxicity that occurs with older patients. There is also an expanding literature on organ dysfunction. The overall data seem to indicate that there are a very few age-related changes in the pharmacokinetics of chemotherapy. The small changes that are present have not been clinically significant. It seems that the pattern of toxicity is more reflective of patient selection (functional status, performance status), comorbidity, and drug scheduling. The large number of drugs with significant renal excretion requires careful evaluation of renal function. Future clinical trial design needs to be adapted to older patients. Therefore, drugs, which will be primarily used by older patients, should be studied in older patients. These studies should involve pharmacokinetics, and oral therapies should include measurements of compliance. Phase II trials of new agents should consider prospectively dividing groups of patients by age (i.e., <75 years vs. >or=75 years). Phase I trials should consider accruing older patients. The studies can be performed in the older group by using progressive degrees of functional impairment and increasing comorbidity as a surrogate for dose limiting toxicity. Functional independence as a clinical benefit of cancer treatment in older individuals should be considered as an endpoint. Overall survival may not be an appropriate endpoint in clinical trials in the oldest group. Clinical trials should consider studying long-term functional and medical consequences of cancer treatment in long-term older cancer survivors. Journal editors should encourage the inclusion of age-related analyses in the reporting of clinical trials to provide meaningful information for clinicians caring for older patients. Ideally, the clinical trial design should prospectively incorporate age analysis to maximize clinical benefit of data generated. A careful assessment of medication used in older patients needs to be part of routine evaluation to minimize the adverse effects of polypharmacy.

Retrospective review of cancer patients > or =80 years old treated with chemotherapy at a comprehensive cancer center

CONTEXT

The percentage of cancer patients > or =80 years old is expected to increase in the next few years. However data on the use of chemotherapy in these patients are limited.

OBJECTIVE

We conducted a retrospective review to define the profile of patients > or =80 years old who received chemotherapy at our center and assess their survival.

DESIGN, SETTING AND PARTICIPANTS

Patients > or =80 years treated with chemotherapy between 1 January 2000 and 31 December 2004 were included in this analysis.

RESULTS

Of the 4689 patients treated with chemotherapy over the 5-year period, 133 patients (3%) were > or =80 years old. The median age was 83 years. 61% were females and 39% were males. 16% had hematologic tumors and 84% had solid tumors. Gynecological (32%) and aerodigestive cancers (27%) were the most common sites and lung cancer (22%) was the most common cancer. During the first regimen, 512 cycles of chemotherapy were delivered with a median of 3 cycles (range: 1-24 cycles). 49% received single and 51% multidrug regimens. Carboplatin was the most common single agent and carboplatin and paclitaxel was the most common combination among solid tumor patients. 19% of solid tumor patients received radiation with chemotherapy. The 1-year survival among hematologic cancer and solid tumor patients was 65% and 48%, respectively. Stage of disease was the only statistically significant factor predicting survival.

CONCLUSIONS

In cancer patients > or =80 years old selected for chemotherapy, both single and multi-agent therapy appeared to be feasible.

Clinical pharmacology of cancer therapies in older adults

This abbreviated review outlines the physiologic changes associated with aging, and examines how these changes may affect the pharmacokinetics and pharmacodynamics of anticancer therapies. We also provide an overview of studies that have been conducted evaluating the pharmacology of anticancer therapies in older adults, and issue a call for further research.

Cytotoxic therapy for the elderly with metastatic breast cancer: A review on safety, pharmacokinetics and efficacy

As the incidence of invasive breast cancer, mainly developing at older age, is rising, the absolute number of elderly developing metastatic disease is also increasing. In view of improved life expectancy, sociocultural changes and better supportive measures for chemotherapy-induced toxicity, there is an increasing request for the administration of chemotherapy in elderly. At the moment, medical oncologists are still reluctant to use chemotherapy in elderly partly because of concern about increased toxicity and poor tolerability of this patient cohort, and the inability to appropriately select elderly that may benefit from chemotherapy. The question is whether this attitude remains justified. In this review, the current status of clinical research in the area of metastatic breast cancer regarding toxicity and activity of chemotherapy in older breast cancer patients is discussed. Further, data on pharmacokinetics are emphasised as age-related physiologic changes may affect these features with consequences for toxicity and decision-making. Moreover, data on assessment tools trying to characterise the 'functional age' are reviewed. In general, the literature data are scarce and hampered by major limitations, while pharmacokinetic data indicate that a different approach in older breast cancer patients does not always seem justified. To increase our knowledge aiming at optimisation of cancer treatment in elderly, there is a clear necessity for prospective, well-designed studies with emphasis on the particular requirements of older patients and incorporation of pharmacokinetic and -dynamic evaluation of cytotoxic agents used in this specific group. As in other research areas, maximal progress will be achieved by joined efforts of co-operative research groups.

International Society of Geriatric Oncology Chemotherapy Taskforce: evaluation of chemotherapy in older patients--an analysis of the medical literature

The elderly comprise the majority of patients with cancer and are the recipients of the greatest amount of chemotherapy. Unfortunately, there is a lack of data to make evidence-based decisions with regard to chemotherapy. This is due to the minimal participation of older patients in clinical trials and that trials have not systematically evaluated chemotherapy. This article reviews the available information with regard to chemotherapy and aging provided by a task force of the International Society of Geriatric Oncology (SIOG). Due to the lack of prospective data, the conclusions and recommendations made are a consensus of the participants. Extrapolation of data from younger to older patients is necessary, particularly to those patients older than 80 years, for which data is almost entirely lacking. The classes of drugs reviewed include alkylators, antimetabolites, anthracyclines, taxanes, camptothecins, and epipodophyllotoxins. Clinical trials need to incorporate an analysis of chemotherapy in terms of the pharmacokinetic and pharmacodynamic effects of aging. In addition, data already accumulated need to be reanalyzed by age to aid in the management of the older cancer patient.

Pharmacogenetics of paclitaxel metabolism

Paclitaxel is one of the most widely used and effective anticancer drugs. Paclitaxel's clinical utility spans many tumor sites, including treatment of ovarian, breast, lung, head and neck, and unknown primary cancers. As is the case with most chemotherapy drugs, paclitaxel is administered empirically with little individualization of dose other than adjustment for body surface area. Metabolism of the drug is predominantly by the liver by cytochromes P450 2C8 and 3A4. Recent evidence points to the presence of polymorphisms in these enzymes. The clinical relevance of these polymorphisms is not yet fully explored, though they are expected to be key in fulfilling the ultimate goal of individualized dosing of paclitaxel. Here we review the pharmacology of paclitaxel and consider the possible effects pharmacogenetics may have on paclitaxel therapy.

Variants in the SLCO1B3 Gene: Interethnic Distribution and Association with Paclitaxel Pharmacokinetics

To explore retrospectively the relationships between paclitaxel pharmacokinetics and three known, non-synonymous single-nucleotide polymorphisms (SNPs) in SLCO1B3, the gene encoding organic anion transporting polypeptide (OATP)1B3. Accumulation of [(3)H]paclitaxel was studied in Xenopus laevis oocytes injected with cRNA of Oatp1b2, OATP1A2, OATP1B1, OATP1B3, OAT1, OAT3, OCT1, and NTCP. The 334T>G (Ser112Ala), 699G>A (Met233Ile), and 1564G>T (Gly522Cys) loci of SLCO1B3 were screened in 475 individuals from five ethnic groups and 90 European Caucasian cancer patients treated with paclitaxel. Only OATP1B3 was capable of transporting paclitaxel to a significant extent (P=0.003). The 334T>G and 699G>A SNPs were less common in the African-American and Ghanaian populations (P<0.000001). Paclitaxel pharmacokinetics were not associated with the studied SNPs or haplotypes (P>0.3). The studied SNPs in SLCO1B3 appear to play a limited role in the disposition of paclitaxel, although their clinical significance in other ethnic populations remains to be investigated.

Prospective Evaluation of the Relationship of Patient Age and Paclitaxel Clinical Pharmacology: Cancer and Leukemia Group B (CALGB 9762)

Purpose

To prospectively evaluate the pharmacokinetics and toxicity profile of paclitaxel in relation to patient age in adults ≥ 55 years old.

Patients and Methods

Paclitaxel was administered at 175 mg/m2 for 3 hours to 153 patients, 46 of whom were ≥ 75 years of age. Pharmacokinetic and toxicity assessments were performed. Data were analyzed by cohort (cohort 1, age 55 to 64 years; cohort 2, age 65 to 74 years; cohort 3, age ≥ 75 years).

Results

Paclitaxel concentration versus time (AUC) and total-body clearance (CLtb) data were available for 122 patients (cohort 1, 46 patients; cohort 2, 44 patients; cohort 3, 32 patients). Mean paclitaxel AUC increased across cohorts (P = .01). Mean (SE) AUCs were 22.4 (2.5) μmol/L × hour, 26.2 (2.8) μmol/L × hour, and 31.7 (5.6) μmol/L × hour for cohorts 1, 2, and 3, respectively. There was a corresponding significant (P = .007) age-related decrease in mean (SE) paclitaxel CLtb (cohort 1, 11.0 [0.7] L/h/m2; cohort 2, 9.3 [0.6] L/h/m2; cohort 3, 8.2 [0.6] L/h/m2). Patients in cohort 3 experienced significantly lower absolute neutrophil count nadirs than did younger groups (P = .02). There was also a significant increase in percentage of patients with ≥ grade 3 neutropenia across age cohorts (cohort 1, 22%; cohort 2, 35%; cohort 3, 49%; P = .006). However, the increased exposure of patients to paclitaxel and increased neutropenia were not reflected in adverse clinical sequelae such as hospitalization for toxicity (P = .82), receiving intravenous antibiotics (P = .21), or experiencing a temperature more than 38°C (P = .45).

Conclusion

Although paclitaxel CLtb decreases with increasing patient age, there is great interpatient variability. Cooperative group studies to evaluate the effect of aging on pharmacokinetics are feasible.

Quantitative effect of gender, age, liver function, and body size on the population pharmacokinetics of Paclitaxel in patients with solid tumors

BACKGROUND

The aim of this study was to quantitatively assess the effect of anthropometric and biochemical variables and third-space effusions on paclitaxel pharmacokinetics in solid tumor patients.

MATERIALS AND METHODS

Plasma concentration-time data of paclitaxel were collected in patients with non-small cell lung cancer (n = 84), ovarian cancer (n = 40), and various solid tumors (n = 44), totaling 168 patients. Paclitaxel was given as a 3-hour infusion (n = 163) at doses ranging from 100 to 250 mg/m(2), or as a 24-hour infusion (n = 5) at a dose of 135 or 175 mg/m(2). Data were analyzed using nonlinear mixed-effect modeling.

RESULTS

A three-compartment model with saturable elimination and distribution was used to describe concentration-time data. Male gender and body surface area were positively correlated with maximal elimination capacity of paclitaxel (VM(EL)); patient age and total bilirubin were negatively correlated with VM(EL) (P < 0.005 for all correlations). Typically, male patients had a 20% higher VM(EL); a 0.2 m(2) increase of body surface area led to a 9% increase of VM(EL); a 10-year increase of patient age led to a 5% decrease of VM(EL); and a 10-micromol increase of total bilirubin led to a 14% decrease of VM(EL). Third-space effusions were not correlated with paclitaxel pharmacokinetics.

CONCLUSIONS

This extended retrospective population analysis showed patient gender to significantly and independently affect paclitaxel distribution and elimination. Body surface area, total bilirubin, and patient age were confirmed to affect paclitaxel elimination. This pharmacokinetic model allowed quantification of the covariate effects on the elimination of paclitaxel and may be used for covariate-adapted paclitaxel dosing.

Association of CYP2C8, CYP3A4, CYP3A5, and ABCB1 polymorphisms with the pharmacokinetics of paclitaxel

PURPOSE

To retrospectively evaluate the effects of six known allelic variants in the CYP2C8, CYP3A4, CYP3A5, and ABCB1 genes on the pharmacokinetics of the anticancer agent paclitaxel (Taxol).

EXPERIMENTAL DESIGN

A cohort of 97 Caucasian patients with cancer (median age, 57 years) received paclitaxel as an i.v. infusion (dose range, 80-225 mg/m(2)). Genomic DNA was analyzed using PCR RFLP or using Pyrosequencing. Pharmacokinetic variables for unbound paclitaxel were estimated using nonlinear mixed effect modeling. The effects of genotypes on typical value of clearance were evaluated with the likelihood ratio test within NONMEM. In addition, relations between genotype and individual pharmacokinetic variable estimates were evaluated with one-way ANOVA.

RESULTS

The allele frequencies for the CYP2C8*2, CYP2C8*3, CYP2C8*4, CYP3A4*3, CYP3A5*3C, and ABCB1 3435C>T variants were 0.7%, 9.2%, 2.1%, 0.5%, 93.2%, and 47.1%, respectively, and all were in Hardy-Weinberg equilibrium. The population typical value of clearance of unbound paclitaxel was 301 L/h (individual clearance range, 83.7-1055 L/h). The CYP2C8 or CYP3A4/5 genotypes were not statistically significantly associated with unbound clearance of paclitaxel. Likewise, no statistically significant association was observed between the ABCB1 3435C>T variant and any of the studied pharmacokinetic variables.

CONCLUSIONS

This study indicates that the presently evaluated variant alleles in the CYP2C8, CYP3A4, CYP3A5, and ABCB1 genes do not explain the substantial interindividual variability in paclitaxel pharmacokinetics.

Prospective evaluation of the pharmacokinetics and toxicity profile of docetaxel in the elderly

PURPOSE

To prospectively study the pharmacokinetics and toxicity profile of docetaxel in elderly patients with cancer.

PATIENTS AND METHODS

Docetaxel was administered at a dose 75 mg/m(2) once every 3 weeks to 25 elderly cancer patients aged >/= 65 years and 26 cancer patients aged younger than 65 years. Pharmacokinetic studies and toxicity assessments were performed during the first cycle of therapy.

RESULTS

Of 51 patients treated, 20 aged >/= 65 years (median, 71 years; range, 65 to 80 years) and 20 aged younger than 65 years (median, 53 years; range, 26 to 64 years) were assessable for pharmacokinetic studies, and 39 were assessable for toxicity. Patient characteristics were similar (P >/= .15) between the two cohorts. Mean docetaxel clearance was not altered in the elderly versus younger patients: 30.1 L/h (standard deviation [SD] 18.3 L/h) v 30.0 L/h (SD, 14.8 L/h; P = .98). The percentage of patients with grade 4 and febrile neutropenia was higher in the elderly (63% and 16%, respectively) versus younger (30% and 0%, respectively) cohort, although this observation did not reach a level of statistical significance (P = .056). From logistic regression analysis, the odds ratio for a patient aged 65 years was 1.98 for developing grade 4 neutropenia compared with a patient aged 50 years (P = .091).

CONCLUSION

Docetaxel plasma pharmacokinetics are unaltered in elderly patients. Patients aged >/= 65 years appear to be more sensitive to docetaxel-induced neutropenia.

Weekly Paclitaxel and Gemcitabine in Advanced Transitional-Cell Carcinoma of the Urothelium: A Phase II Hoosier Oncology Group Study

Purpose

To evaluate the efficacy and toxicity of weekly paclitaxel and gemcitabine in patients with advanced transitional-cell carcinoma (TCC) of the urothelial tract.

Patients and Methods

Patients with advanced unresectable TCC were enrolled onto this multicenter, community-based, phase II trial. Initially, patients were treated with paclitaxel 110 mg/m2and gemcitabine 1,000 mg/m2by intravenous infusion on days 1, 8, and 15 every 28 days. Patients who had an objective response or stable disease continued treatment for a maximum of six courses. Paclitaxel was decreased to 90 mg/m2and gemcitabine was decreased to 800 mg/m2for the last 12 patients because of a concerning incidence of pulmonary toxicity in the first 24 patients.

Results

Thirty-six patients were enrolled between September 1998 and March 2003. Twenty-four patients received the higher doses of paclitaxel and gemcitabine, and 12 patients received the lower doses. Twenty-five (69.4%) of 36 patients had major responses to treatment, including 15 patients (41.7%) with complete responses. With a median follow-up time of 38.7 months, the median survival time was 15.8 months. Grade 3 and 4 toxicities included granulocytopenia (36.1%), thrombocytopenia (8.3%), and neuropathy (16.7%). Five patients (13.9%) had grades 3 to 5 pulmonary toxicity, and one patient had grade 2 pulmonary toxicity.

Conclusion

Weekly paclitaxel and gemcitabine is an active regimen in the treatment of patients with advanced TCC. However, because of the high incidence of pulmonary toxicity associated with this schedule of paclitaxel and gemcitabine, we recommend against the use of this regimen in this patient population.

Effect of valspodar on the pharmacokinetics of unbound paclitaxel

The aim of this multicenter study was to determine whether valspodar (Amdray; code designation, SDZ PSC 833), a potent P-glycoprotein (P-gp) inhibitor, affects the pharmacokinetics of unbound paclitaxel (Cu). Data were obtained from 31 patients with advanced breast cancer. Thirteen patients were treated with paclitaxel alone (3-h infusion at 175 mg/m2) and another 18 received paclitaxel (3-h infusion at 70 mg/m2) in combination with a 21-day cycle of oral valspodar (5 mg/kg given four times a day) starting 1 day before administration of paclitaxel. Serial blood samples were taken in the first course and Cu in plasma determined using equilibrium dialysis with a [G-3H]paclitaxel tracer. The apparent clearance of Cu was not significantly different between the two groups, with mean +/- standard deviation (+/- SD) values of 230 +/- 56.0 and 202 +/- 49.9 L/h/m2 in the absence and presence of valspodar, respectively (P = 0.17). The volume of Cu distribution was slightly larger in the presence of valspodar (1160 +/- 474 vs. 1620 +/- 552 L/m2; P = 0.025), which contributed to a minor difference in the terminal disposition half-life (6.12 +/- 3.42 vs. 8.50 +/- 2.06 h; P = 0.028). These data indicate that (i) valspodar lacks the significant interaction with paclitaxel observed previously with other P-gp modulators, (ii) the majority of the increased toxicity of the combination does not appear to be attributable to increased levels of Cu, and (iii) provide further evidence of the conjecture that the plasma concentration of paclitaxel may not be an appropriate measure to monitor the impact of P-gp inhibition.

Taxanes in elderly breast cancer patients

Breast cancer in elderly patients (70+) is a major health problem that will only increase in the future. Besides adequate local treatment and hormone therapy, there can be an indication for chemotherapy in this patient group. Due to concerns of excessive toxicity, there is often a defeatist attitude towards chemotherapy in elderly patients. As taxanes are considered to be the most effective drugs in breast cancer, and as the weekly regimens seem at least as effective as the 3-weekly regimens but with less toxicity, these weekly regimens are very attractive for elderly breast cancer patients. Many different doses have been used for the weekly taxane regimens in phase II trials. Although large comparative studies are lacking, pharmacological studies are suggestive for a decreased clearance of both paclitaxel and docetaxel in elderly patients compared to non-elderly patients. It seems therefore safe to use the lower range of proposed doses of the weekly regimens until further data provide stronger evidence for optimal dosing in elderly patients. A dose of paclitaxel 80 mg/m(2)/week and docetaxel 36 mg/m(2)/week seems tolerable for elderly patients without excessive toxicity and with impressive response rates. The dose limiting toxicity for 3-weekly taxanes, severe neutropaenia, is generally very limited in weekly regimens, also in the elderly or frail patients. However, neuropathy (paclitaxel) or fatigue and fluid retention (docetaxel) can be troublesome, and eventually require dose modifications. In general however, weekly taxanes are a reasonable option for older patients with metastatic breast cancer.

Weekly paclitaxel as first-line chemotherapy for elderly patients with metastatic breast cancer. A multicentre phase II trial

Paclitaxel is a cytotoxic agent with proven antitumour activity in metastatic breast cancer. Weekly administration of paclitaxel has demonstrated sustained efficacy together with a more favourable toxicity profile (e.g. less myelotoxicity) than the 3-weekly administration. This study evaluates the activity and toxicity of weekly paclitaxel (Taxol(R)) as first-line chemotherapy in elderly patients (>70 years of age) with hormone-refractory metastatic breast cancer. Patients with metastatic breast cancer received 80 mg/m(2) paclitaxel administered weekly on days 1, 8 and 15 of a 28-day cycle. Additional cycles were given until disease progression, or unacceptable toxicity. A dose increase to 90 mg/m(2) was allowed in the absence of toxicity. 26 Patients received a total of 101 cycles (median 4, range 1-11). 22 patients completed at least two cycles (six administrations). In 23 patients who were evaluable for response, there were 10 partial responses (38%), 9 patients with stable disease (35%), while 4 patients had disease progression (15%). The median duration of response was 194 days (>6 months). Overall treatment was relatively well tolerated, but 8 patients (32%) had to prematurely discontinue treatment because of fatigue. Neuropathy >grade 1 was noted only after five or more cycles in 4 patients. Weekly paclitaxel at this dose and schedule is an effective treatment regimen in the elderly patient with metastatic breast cancer, and is feasible, but yields relevant fatigue in a subset of patients.