Relationship between specific adverse events and efficacy of exemestane therapy in early postmenopausal breast cancer patients

BACKGROUND

Many adverse events (AEs) associated with aromatase inhibitors (AIs) involve symptoms related to the depletion of circulating estrogens, and may be related to efficacy. We assessed the relationship between specific AEs [hot flashes (HF) and musculoskeletal AEs (MSAE)] and survival outcomes in Dutch and Belgian patients treated with exemestane (EXE) in the Tamoxifen Exemestane Adjuvant Multinational (TEAM) trial. Additionally, the relationship between hormone receptor expression and AEs was assessed.

METHODS

Efficacy end points were relapse-free survival (RFS), overall survival (OS) and breast cancer-specific mortality (BCSM), starting at 6 months after starting EXE treatment. AEs reported in the first 6 months of treatment were included. Specific AEs comprised HF and/or MSAE. Landmark analyses and Cox proportional hazards models assessed survival differences up to 5 years.

RESULTS

A total of 1485 EXE patients were included. Patients with HF had a better RFS than patients without HF [multivariate hazard ratio (HR) 0.393, 95% confidence interval (CI) 0.19-0.813; P = 0.012]. The occurrence of MSAE versus no MSAE did not relate to better RFS (multivariate HR 0.677, 95% CI 0.392-1.169; P = 0.162). Trends were maintained for OS and BCSM. Quantitative hormone receptor expression was not associated with specific AEs.

CONCLUSIONS

Some AEs associated with estrogen depletion are related to better outcomes and may be valuable biomarkers in AI treatment.

Recommendations on management of EGFR inhibitor-induced skin toxicity: a systematic review

Epidermal growth factor receptor (EGFR) inhibitors, such as the monoclonal antibodies cetuximab and panitumumab, have proven efficacy in various types of cancer. However, these agents frequently result in skin toxicity, due to the expression of the EGFR in the skin. A correlation between the occurrence of skin toxicity and anti-tumor activity has been suggested in several phase III studies. However, since skin toxicity may impair the quality of life, and severe skin toxicity requires dose reduction or interruption, adequate and timely management of skin toxicity is important to maximize the anti-tumor efficacy of the EGFR inhibitor, as well as maintaining the patient's quality of life. Due to the small number of randomized controlled trials conducted in the field of EGFR inhibitor-induced skin toxicity so far, it is not possible yet to generate evidence based guidelines on its management. Here, we review and discuss available trials and case studies reporting on the management of EGFR inhibitor-induced skin toxicity.

Development of a computerised alert system, ADEAS, to identify patients at risk for an adverse drug event

INTRODUCTION

Adverse drug events (ADEs) are frequent and pose an important risk for patients treated with drugs. Fortunately, a substantial part of ADEs is preventable, and computerised physician order entry with a sophisticated clinical decision support system may be used to reach this goal.

OBJECTIVE

To develop a new automated system that could improve the quality of medication surveillance. The system should focus on detecting patients at risk for an ADE by combining data from the hospital information system and computerised physician order entry (drug prescription data, drug-drug interaction alerts, clinical chemical laboratory parameters, demographic features), using clinical rules.

METHODS

The clinical rules were formulated in a multidisciplinary team, based on seven risk categories. The new system was composed in a guideline-based decision support framework consisting of both a guideline development module and a decision support module. A total of 121 clinical rules were built into the system. Validation of the system and a proof of principle test were performed.

RESULTS

The adverse drug event alerting system (ADEAS) was developed and validated successfully. The proof of principle test showed that ADEAS has potential clinical usefulness. ADEAS generated alerts and detected additional potential risk situations, which were not generated by the conventional medication surveillance.

CONCLUSION

We developed a pharmacy decision support system ADEAS that focuses on the detection of situations prone to lead to an ADE and might help clinicians to take timely corrective interventions and thereby can prevent patient harm.

Pharmacogenetics: from bench to byte--an update of guidelines

Currently, there are very few guidelines linking the results of pharmacogenetic tests to specific therapeutic recommendations. Therefore, the Royal Dutch Association for the Advancement of Pharmacy established the Pharmacogenetics Working Group with the objective of developing pharmacogenetics-based therapeutic (dose) recommendations. After systematic review of the literature, recommendations were developed for 53 drugs associated with genes coding for CYP2D6, CYP2C19, CYP2C9, thiopurine-S-methyltransferase (TPMT), dihydropyrimidine dehydrogenase (DPD), vitamin K epoxide reductase (VKORC1), uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1), HLA-B44, HLA-B*5701, CYP3A5, and factor V Leiden (FVL).

Pharmacogenetic interaction analysis for the efficacy of systemic treatment in metastatic colorectal cancer

BACKGROUND

Pharmacogenetic markers related to drug metabolism and mechanisms of action could help to better select patients with metastatic colorectal cancer (mCRC) for treatment. Genetic interaction analysis is used as a rational tool to study the contribution of polygenic variation in relation to drug response.

PATIENTS AND METHODS

A selection of 17 polymorphisms in genes encoding drug targets, pathway molecules and detoxification enzymes was analyzed in 279 previously untreated mCRC patients treated with capecitabine, oxaliplatin and bevacizumab (CAPOX-B). Multifactor dimensionality reduction analysis was used to identify a genetic interaction profile for progression-free survival (PFS).

RESULTS

Median PFS was 10.9 [95% confidence interval (CI) 9.4-12.4] months. A genetic interaction profile consisting of the TYMS enhancer region and VEGF +405G>C polymorphisms was significantly associated with PFS. Median PFS was 13.3 (95% CI 11.4-15.3) and 9.7 (95% CI 7.6-11.8) months for the beneficial and unfavorable genetic profiles, respectively, corresponding to a hazards ratio for PFS of 1.58 (95% CI 1.14-2.19). None of the studied polymorphisms were individually associated with PFS.

CONCLUSIONS

Our results support a genetic interaction between the TYMS enhancer region and VEGF +405G>C polymorphisms as a predictor of the efficacy of CAPOX-B in mCRC patients.

The tolerability and efficacy of low-dose simvastatin in statin-intolerant patients

BACKGROUND/AIM

Statin intolerance is increasingly recognized as a therapy limiting factor in the primary and secondary prevention of cardiovascular disease. Since vulnerability to dose related adverse events differ between subjects treated with statins we hypothesized low-dose simvastatin would be tolerated and effective in statin-intolerant patients.

METHOD

A single center open label prospective observational study was performed assessing tolerability and efficacy of low-dose simvastatin treatment in 35 statin-intolerant patients. Statin intolerance was defined as not being able to tolerate a registered dose statin due to myalgia-myopathy, myositis, or elevation of serum liver enzyme levels. These statin-intolerant patients were treated with simvastatin with an initial dose of 2.5mg every other day. The dose was titrated upwards if possible. Tolerability was defined as remaining on treatment. Efficacy was defined as change of LDL-cholesterol compared to baseline.

RESULTS

The reached simvastatin dose ranged from 0.825 to 8.75mg/day with a mean dose of 4mg/day. Fifty-seven percent of the patients tolerated low-dose therapy and remained on treatment. Of these patients, 30% noted recurrent myalgia. Low-dose simvastatin significantly decreased mean(SD) LDL-cholesterol levels with 25.9(12.1)% (p<0.001). Eleven percent of the patients reached LDL-cholesterol target levels (<2.6mmol/l) in an intention to treat analysis and in 20% of patients that tolerated low-dose simvastatin.

CONCLUSION

Low-dose simvastatin therapy is tolerated in a considerable proportion of statin-intolerant patients with significant lipid lowering efficacy. Low-dose statin therapy can be considered in multidrug regimens in statin-intolerant patients.

Pharmacogenetics in oncology: a promising field

Pharmacogenetics is a rapidly developing field, especially in oncology. In the most ideal situation pharmacogenetics will allow oncologists to individualize therapy based on patients' individual germline genetic test results. This can help to improve efficacy, reduce toxicity and predict non-responders in a way that alternative therapy can be chosen or individual dose adjustments can be made. Multiple pathways have been studied extensively of which a brief review is presented here. Increased 5FU toxicity is associated with variations in the DPYD gene, TYMS gene and MTHFR gene. Furthermore variations in the UGT1A gene and the ABCB1 gene influence irinotecan metabolism and disposition. Other genetic changes result in reduced DNA repair capacity related to platinum efficacy or reduced cytochrome P450 2D6 activity related to tamoxifen efficacy. Despite the extensive number of pharmacogenetic studies and promising results, it is still unclear when and how pretreatment genetic screening should be implemented in oncology. Future prospective studies should focus on the effect of pharmacogenetics on patient outcome and combine this with cost effectiveness evaluations. Thus supplying us with predictive models helping in deciding when pretreatment genetic screening is useful.

Pharmacogenetics in treatment of rheumatoid arthritis

Over the last decades important progress is being made regarding disease modifying anti-rheumatic drugs (DMARDs) in the treatment of rheumatoid arthritis (RA). Nevertheless, a substantial part of the patients fail to achieve a good response and/or experience toxicity, which limits further treatment leading to progression of inflammation and destruction of joints. These high interindividual differences in drug response gave rise to the need for prognostic markers in order to individualize and optimize therapy with these antirheumatic agents. Besides demographic and clinical factors, studies in the research field of pharmacogenetics have reported potential markers associated with clinical response on treatment with methotrexate and TNF inhibitors. However, publicized conflicting results and underlying interpretation difficulties inhibit drawing definitive conclusions. Presently, clinical implementation of pharmacogenetics as an important step for individualizing drug therapy in RA is not feasible yet. Replication and prospective validation in large patient cohorts are required before pharmacogenetics can be used in clinical practice. This review provides the current state of art in genotyping RA patients as a potential guide for clinical decision making.

Individualizing calcineurin inhibitor therapy in renal transplantation--current limitations and perspectives

Patient variability in clinical response to the calcineurin inhibitors (CNIs) cyclosporine A and tacrolimus partly results from differences in CNI exposure. For tacrolimus drug interactions and genetic variability relate to tacrolimus exposure. Patients carrying the CYP3A5*1 allele have an increased tacrolimus metabolism, hence lower drug exposure. Adjusting the tacrolimus dose to this genotype is a tool to optimize therapy from a pharmacokinetic perspective. In contrast, no genetic variants have been found to clearly relate to cyclosporine A exposure. Despite therapeutic drug monitoring aimed at individualizing CNI therapy, patients still suffer from acute or chronic rejection and CNI toxicity. To further optimize CNI therapy future research may incorporate genetic polymorphisms in proteins involved in CNI pharmacodynamics (i.e. drug target). Proteins potentially relevant for drug response are calcineurin and the CNI binding proteins immunophilins. Moreover, since the expression of the nuclear factor of activated T-cells (NFAT) is reduced after calcineurin inhibition, genetic polymorphisms in the genes encoding NFAT may also be interesting candidates for studying inter-patient differences in CNI efficacy and toxicity. In addition, the existence of isoforms and differences in tissue distribution of the calcineurin protein could potentially explain variable drug response. At present, the focus has been on the metabolism of CNIs and not on variability in the drug target. Therefore, future improvements in CNI therapy are likely to occur from a systems pharmacology approach taking into account genetic markers for both CNI pharmacokinetics and pharmacodynamics.

Glycopyrrolate for sialorrhea in Parkinson disease: a randomized, double-blind, crossover trial

BACKGROUND

Sialorrhea affects approximately 75% of patients with Parkinson disease (PD). Sialorrhea is often treated with anticholinergics, but central side effects limit their usefulness. Glycopyrrolate (glycopyrronium bromide) is an anticholinergic drug with a quaternary ammonium structure not able to cross the blood-brain barrier in considerable amounts. Therefore, glycopyrrolate exhibits minimal central side effects, which may be an advantage in patients with PD, of whom a significant portion already experience cognitive deficits.

OBJECTIVE

To determine the efficacy and safety of glycopyrrolate in the treatment of sialorrhea in patients with PD.

METHODS

We conducted a 4-week, randomized, double-blind, placebo-controlled, crossover trial with oral glycopyrrolate 1 mg 3 times daily in 23 patients with PD. The severity of the sialorrhea was scored on a daily basis by the patients or a caregiver with a sialorrhea scoring scale ranging from 1 (no sialorrhea) to 9 (profuse sialorrhea).

RESULTS

The mean (SD) sialorrhea score improved from 4.6 (1.7) with placebo to 3.8 (1.6) with glycopyrrolate (p = 0.011). Nine patients (39.1%) with glycopyrrolate had a clinically relevant improvement of at least 30% vs 1 patient (4.3%) with placebo (p = 0.021). There were no significant differences in adverse events between glycopyrrolate and placebo treatment.

CONCLUSIONS

Oral glycopyrrolate 1 mg 3 times daily is an effective and safe therapy for sialorrhea in Parkinson disease.

CLASSIFICATION OF EVIDENCE

This study provides Class I evidence that glycopyrrolate 1 mg 3 times daily is more effective than placebo in reducing sialorrhea in patients with Parkinson disease during a 4-week study.

The exon-3 deleted growth hormone receptor polymorphism predisposes to long-term complications of acromegaly

OBJECTIVE

The aim of the study was to evaluate the impact of the genomic deletion of exon 3 of the GH receptor (d3GHR) on long-term clinical outcome of acromegaly in a well-characterized cohort of patients with long-term remission of acromegaly.

DESIGN

We conducted a cross-sectional study.

METHODS

The presence of the d3GHR polymorphism was assessed in 86 acromegalic patients with long-term disease control and related to anthropometric parameters, cardiovascular risk factors, osteoarthritis, bone mineral density, colonic polyps and diverticulae, and dolichocolon.

RESULTS

Fifty-one patients had two wild-type alleles (59%), whereas 29 patients (34%) had one allele and six patients (7%) had two alleles encoding for the d3GHR isoform. Carriers of the d3GHR isoform showed increased prevalence of osteoarthritis, especially of the hip [adjusted odds ratio (OR), 5.2; 95% confidence interval (CI), 3.2-7.1], of adenomatous polyps (adjusted OR, 4.1; 95% CI, 2.4-5.6), and dolichocolon (adjusted OR, 3.2; 95% CI, 1.8-4.6). Anthropometric parameters, cardiovascular risk factors, bone mineral density, and (non)vertebral fractures were not significantly different between patients with and without the d3GHR allele.

CONCLUSION

In patients with long-term cured acromegaly, the d3GHR polymorphism is associated with an increased prevalence of irreversible comorbidities such as osteoarthritis, dolichocolon, and adenomatous colonic polyps, but not with other comorbidities such as cardiovascular risk factors.

Explorative study to identify novel candidate genes related to oxaliplatin efficacy and toxicity using a DNA repair array

Purpose:

To identify new polymorphisms (single nucleotide polymorphisms, SNPs) in DNA repair pathways that are associated with efficacy and toxicity in patients receiving oxaliplatin and capecitabine for advanced colorectal cancer (ACC).

Methods:

We studied progression-free survival (PFS) in 91 ACC patients, of whom germ-line DNA was isolated and genotyped using an Asper Biotech array. Overall survival (OS) and toxicity were studied as secondary end points. A step-wise selection of SNPs was performed, involving univariate and multivariate log-rank tests and Cox regression analysis, with age and performance status as covariates.

Results:

A total of 81 SNPs in 46 genes on the array were selected for further analysis, based on genotyping success rates and minor allele frequencies. After step-wise selection, we found that homozygosity for the ataxia telangiectasia mutated gene (ATM) rs1801516 or excision repair cross-complementing gene (ERCC5) rs1047768 SNPs was associated with shorter PFS; however there were no significant associations (P>0.01) with OS or toxicity.

Discussion:

This is the first study describing the pathway gene approach for the selection of new candidate genes involved in oxaliplatin efficacy and toxicity. The results suggest that the ATM and ERCC5 genes may be associated with oxaliplatin efficacy in ACC.

Time to treatment as an important factor for the response to methotrexate in juvenile idiopathic arthritis

OBJECTIVE

Methotrexate (MTX) is the most commonly used disease-modifying antirheumatic drug in juvenile idiopathic arthritis (JIA). Currently, individual response to MTX cannot be reliably predicted. Identification of clinical and genetic factors that influence the response to MTX could be helpful in realizing the optimal treatment for individual patients.

METHODS

A cohort of 128 JIA patients treated with MTX were studied retrospectively. Eleven clinical parameters and genotypes of 6 single nucleotide polymorphisms in 5 genes related to the mechanism of action of MTX were compared between MTX responders and nonresponders using a multivariate regression analysis.

RESULTS

The time from diagnosis to start of MTX treatment, physician's global assessment at baseline, and the starting dose were significantly associated with the response to MTX at 6 months after initiation. Patients with a shorter time from diagnosis to start of MTX and a higher disease activity according to the physician but with a lower MTX dose showed an increased response. The effect of the starting dose on MTX response seemed to be mainly due to the influence of the systemic JIA subtype. The time from diagnosis to start of MTX treatment and physician's global assessment at baseline were highly correlated. Therefore, the precise effect size of each independent variable could not be determined.

CONCLUSION

In children with JIA, the time from diagnosis to start of MTX appears to be an important factor for MTX response. Our results suggest that an earlier start of MTX treatment will lead to an increased response.

Pharmacokinetics of riluzole: evidence for glucuronidation as a major metabolic pathway not associated with UGT1A1 genotype

Pharmacokinetic studies of riluzole show a large inter-individual variability of the drug's clearance and serum concentrations. Optimizing the individual dosage of riluzole may have the potential to improve the effect of riluzole treatment on survival of patients with amyotrophic lateral sclerosis (ALS). Limited data are available on the in vivo metabolic elimination of riluzole. From in vitro experiments, CYP1A2 seems to be mainly involved in riluzole clearance. However, in vitro studies suggest that formation of riluzole-glucuronide plays a role and may determine the drug's pharmacokinetic variability in patients to some extent. In the current study the formation of riluzole-glucuronide was examined in amyotrophic lateral sclerosis (ALS) patients. It also aimed at relating glucuronidation of riluzole to differential UGT1A1*28 genotypes. The formation of riluzole-glucuronide was confirmed in serum from a group of 14 ALS patients taking riluzole. Riluzole-glucuronide concentrations were positively associated with those of riluzole. In a separate group of 131 ALS patients taking riluzole, the UGT1A1*28 genotype was not associated with trough or peak serum concentrations of riluzole. This study provides evidence that the in vivo metabolic elimination of riluzole in ALS patients involves glucuronidation. The results do not indicate that glucuronidation of riluzole highly contributes to the drug's inter-individual pharmacokinetic variability.

Recent insights in the pharmacological actions of methotrexate in the treatment of rheumatoid arthritis

This review presents recent data supporting the methotrexate (MTX) mechanisms of action, which are likely to account for its anti-proliferative and immunosuppressive effects in rheumatoid arthritis (RA). The effects of MTX in vivo may be mediated by reducing cell proliferation, increasing the rate of apoptosis of T cells, increasing endogenous adenosine release, altering the expression of cellular adhesion molecules, influencing production of cytokines, humoral responses and bone formation. Several reports indicate that the effects of MTX are influenced by genetic variants, specific dynamic processes and micro-environmental elements such as nucleotide deprivation or glutathione levels. The challenge for the future will be linking biological and genetic markers relevant to the response to MTX in RA.

Is statin use associated with a reduced incidence, a reduced Breslow thickness or delayed metastasis of melanoma of the skin?

BACKGROUND

Statins show anticancer activity in melanoma cells. We investigated the association between statins and incidence and Breslow thickness of cutaneous melanoma (CM).

METHODS

Data were used from PHARMO, a pharmacy database, and PALGA, a pathological database, in the Netherlands. Cases had a primary CM diagnosis between January 1st 1991 and December 14th 2004, were 18 years and had 3 years of follow up in PHARMO before CM diagnosis. Controls were matched for gender, date of birth and geographic region. Analyses were adjusted for age, gender, year of diagnosis, number of medical diagnoses and the use of NSAIDs and oestrogens.

FINDINGS

Finally, 1318 cases and 6786 controls were selected. CM risk was not associated with statin use (> or = 0.5 years) (adjusted odds ratio (OR)=0.98, 95% confidence interval (CI)=0.78-1.2). However, statin use was associated with a reduced Breslow thickness (-19%, 95% CI=-33, -2.3, p=0.03).

CONCLUSION

Our study suggests protective effects of statins on melanoma progression.

An association study of riluzole serum concentration and survival and disease progression in patients with ALS

Patients with amyotrophic lateral sclerosis (ALS) who are treated with the antiglutamatergic drug riluzole receive a fixed-dose regimen of 50 mg b.i.d. The drug has been shown to increase tracheostomy-free survival by 3-6 months. The pharmacokinetics of riluzole show a high interindividual variability. Riluzole serum concentrations are associated with side effects and ALS symptoms, but the effect of the actual blood level of riluzole on disease progression and survival is unknown. We measured trough and peak serum concentrations of riluzole in 160 patients with ALS, and estimated the area under the curve for one dosage interval (AUCi) using a Bayesian method. We then determined the association between riluzole AUCi and survival over a 5-year period, and between riluzole AUCi and disease progression, defined by the rates of decline of arm strength and vital lung capacity. No significant association was found between riluzole AUCi and survival or disease progression.

Cyclopentenyl cytosine (CPEC): an overview of its in vitro and in vivo activity

The experimental cytotoxic drug cyclopentenyl cytosine (CPEC) is an analogue of cytidine. Besides its antiviral effect, its potential use in the treatment of cancer has become an important area of research. CPEC is activated by intracellular phosphorylation ultimately forming its metabolite CPEC-TP. CPEC-TP is a non competitive inhibitor of cytidine-5'-triphosphate synthetase (CTP-synthetase), an important enzyme in the formation of CTP. Studies have shown that cancer cells have a high CTP synthetase activity, thus making them interesting targets for chemotherapy. CPEC has been preclinically studied in different malignancy models. In vitro results on leukemia show activity in the nanomolar range on several cell lines. However in vivo results are conflicting and the findings vary from increase in life span over 100% to only limited effectiveness. Interesting results have been obtained in colorectal and neuroblastoma cells. In several neuroblastoma cell lines incubation with CPEC in combination with cytarabine or gemcitabine has resulted in increased cell death compared to incubation with with only one of the agents. CPEC has been studied in a phase I trial in patients with solid tumors. In five of 26 patients unexplained cardiotoxicity (extreme hypotension) occurred. The cardiotoxic effects could not be reproduced in animal models. However, precautions should be taken when using this drug in future clinical trials. Low dosage of CPEC seems necessary and intensive cardiac monitoring is advisable. In this manuscript, it is demonstrated that CPEC has an anti-cancer effect in several tumor models: CPEC might be a potentially useful drug in anticancer treatment.

Insights into the role of heritable genetic variation in the pharmacokinetics and pharmacodynamics of anticancer drugs

Pharmacogenetics in oncology will ideally allow oncologists to individualise therapy based on a genetic test result. Severe toxicity and clinically significant underdosing may be avoided, whereas predicted non-responders can be offered alternative therapy. This manuscript gives an overview of heritable variants in the genes of nine enzymes or pathways that have been studied most extensively in anticancer chemotherapy. Even though many pharmacogenetic association studies have been published, there is a need for more research. In particular, there is a need for replication of data and development of predictive models. Prospective trials are required to establish clinical value and cost-effectiveness of pharmacogenetic testing in oncology.