Saroj Niraula

Toxicity of Adjuvant Endocrine Therapy in Postmenopausal Breast Cancer Patients: A Systematic Review and Meta-analysis

BACKGROUND Aromatase inhibitors are associated with consistent improvements in disease-free survival but not in overall survival. We conducted a literature-based meta-analysis of randomized trials to examine whether the relative toxicity of aromatase inhibitors compared with tamoxifen may explain this finding. METHODS We conducted a systematic review to identify randomized controlled trials that compared aromatase inhibitors and tamoxifen as primary adjuvant endocrine therapy in postmenopausal women by searching MEDLINE, EMBASE, and databases of the American Society of Clinical Oncology and San Antonio Breast Cancer Symposium. Odds ratios (ORs), 95% confidence intervals (CIs), absolute risks, and the number needed to harm associated with one adverse event were computed for prespecified serious adverse events including cardiovascular disease, cerebrovascular disease, bone fractures, thromboembolic events, endometrial carcinoma and other second cancers not including new breast cancer. All statistical tests were two-sided. RESULTS Seven trials enrolling 30,023 patients met the inclusion criteria. Longer duration of aromatase inhibitor use was associated with increased odds of developing cardiovascular disease (OR = 1.26, 95% CI = 1.10 to 1.43, P < .001; number needed to harm = 132) and bone fractures (OR = 1.47, 95% CI = 1.34 to 1.61, P < .001; number needed to harm = 46), but a decreased odds of venous thrombosis (OR = 0.55, 95% CI = 0.46 to 0.64, P < .001; number needed to harm = 79) and endometrial carcinoma (OR = 0.34, 95% CI = 0.22 to 0.53, P < .001; number needed to harm = 258). Five years of aromatase inhibitors was associated with a non-statistically significant increased odds of death without recurrence compared with 5 years of tamoxifen alone or tamoxifen for 2-3 years followed by an aromatase inhibitor for 2-3 years (OR = 1.11, 95% CI = 0.98 to 1.26, P = .09). CONCLUSIONS The cumulative toxicity of aromatase inhibitors when used as up-front treatment may explain the lack of overall survival benefit despite improvements in disease-free survival. Switching from tamoxifen to aromatase inhibitors reduces this toxicity and is likely the best balance between efficacy and toxicity.

Metformin in cancer: translational challenges.

The anti-diabetic drug metformin is rapidly emerging as a potential anti-cancer agent. Metformin, effective in treating type 2 diabetes and the insulin resistance syndromes, improves insulin resistance by reducing hepatic gluconeogenesis and by enhancing glucose uptake by skeletal muscle. Epidemiological studies have consistently associated metformin use with decreased cancer incidence and cancer-related mortality. Furthermore, numerous preclinical and clinical studies have demonstrated anti-cancer effects of metformin, leading to an explosion of interest in evaluating this agent in human cancer. The effects of metformin on circulating insulin levels indicate a potential efficacy towards cancers associated with hyperinsulinaemia; however, metformin may also directly inhibit tumour growth. In this review, we describe the mechanism of action of metformin and summarise the epidemiological, clinical and preclinical evidence supporting a role for metformin in the treatment of cancer. In addition, the challenges associated with translating preclinical results into therapeutic benefit in the clinical setting will be discussed.

Treatment of Prostate Cancer With Intermittent Versus Continuous Androgen Deprivation: A Systematic Review of Randomized Trials

PURPOSE Uncertainty exists regarding benefits of intermittent androgen deprivation (IAD) compared with continuous androgen deprivation (CAD) for treatment of prostate cancer. On the basis of a systematic review of evidence, our aim was to formulate a recommendation for either IAD or CAD to treat relapsing, locally advanced, or metastatic prostate cancer. METHODS We searched literature published up to September 2012 from MEDLINE, EMBASE, the Cochrane Library, and major conference proceedings. We included randomized controlled trials comparing IAD and CAD if they reported overall survival (OS) or biochemical/radiologic time to disease progression. RESULTS Nine studies with 5,508 patients met our criteria. There were no significant differences in time-to-event outcomes between the groups in any studies. The pooled hazard ratio (HR) for OS was 1.02 (95% CI, 0.94 to 1.11) for IAD compared with CAD, and the HR for progression-free survival was 0.96 (95% CI, 0.76 to 1.20). More prostate cancer-related deaths with IAD tended to be balanced by more deaths not related to prostate cancer with CAD. Superiority of IAD for sexual function, physical activity, and general well-being was observed in some trials. Median cost savings with IAD was estimated to be 48%. CONCLUSION There is fair evidence to recommend use of IAD instead of CAD for the treatment of men with relapsing, locally advanced, or metastatic prostate cancer who achieve a good initial response to androgen deprivation. This recommendation is based on evidence against superiority of either strategy for time-to-event outcomes and substantial decrease with IAD in exposure to androgen deprivation, resulting in less cost, inconvenience, and potential toxicity.

Risk of Incremental Toxicities and Associated Costs of New Anticancer Drugs: A Meta-Analysis

PURPOSE There are increasing reports of rare but serious toxicities caused by new anticancer drugs, and there are costs associated with their management. METHODS We identified anticancer drugs approved by the U.S. Food and Drug Administration from 2000 to 2011 and pivotal trials supporting their registration. Twelve frequent grade 3 to 4 adverse event (AEs) were weighted and pooled in a meta-analysis. Estimates of incremental drug prices and incremental costs for management of AEs were calculated according to type of new agent based on target specificity. RESULTS We identified 41 studies comprising 27,539 patients and evaluating 19 experimental drugs. Agents directed against a specific molecular target on cancer cells had a lower incidence of grade 3 to 4 toxicities compared with controls (median risk ratio [RR], 0.67; P = .22), whereas less-specific targeted agents, including angiogenesis inhibitors (median RR, 3.39; P < .001) and chemotherapeutic agents (median RR, 1.73; P < .001), were more toxic. Risk was increased regardless of whether the control arm contained active treatment (RR, 2.11; P < .001) or not (RR, 3.02; P < .001). Median incremental drug price for experimental agents was

Influence of concurrent medications on outcomes of men with prostate cancer included in the TAX 327 study

6,000 per patient per month. Median cost of managing toxicity was low compared with drug costs but higher than controls for treatment with less-specific targeted agents and chemotherapies. CONCLUSION Newly approved anticancer drugs are associated with increased toxicity, except for agents with a specific molecular target on cancer cells. Management of toxicity leads to a small increase in overall cost of treatment. Frequency of toxicity and associated costs are likely higher in less-selected patients treated in general oncologic practice. Development of biomarker-driven agents should be encouraged.

Broadening horizons in medical management of prostate cancer

OBJECTIVES The TAX 327 trial was pivotal in establishing docetaxel in castration refractory metastatic prostate cancer. Various commonly prescribed and over-the-counter co-administered medications are thought to exhibit anti-neoplastic properties and/or could potentially have pharmacokinectic interactions with docetaxel lessening the effectiveness of chemotherapy. METHODS To examine the effect of on prostate cancer outcomes within this trial, we examined overall survival, prostate-specific antigen (PSA) response, percent PSA reduction, pain response and QOL responses for 14 families of medications including metformin, digoxin, verapamil, proton pump inhibitors, nitrates, statins, cox-2 inhibitors, warfarin, heparins, ascorbic acid, selenium, tocopherol, antidepressants and erythropoietin. RESULTS Our findings did not reveal any medication that had a significant additive or synergistic effect with docetaxel. We did note, however, that patients on digoxin or verapamil had poorer overall survival, possibly due to a trend of fewer cycles of administered chemotherapy being administered to the verapamil group, consistent with a pharmacokinectic interaction. CONCLUSIONS These data are only hypothesis-generating given the statistical limitations, but may form a basis for similar future analysis in other malignancies. The data suggest the need to be aware of pharmacokinectic interactions with medications that may interact with docetaxel.

Relevance of randomised controlled trials in oncology

Abstract Hormonal therapy. Testosterone suppression achieved either medically or surgically is the standard initial treatment for men with advanced prostate cancer. Most men respond but the disease progresses after a median of 1–2 years. Clinical trials suggest that intermittent androgen deprivation therapy (ADT) provides equal or longer time to castration-independence than continuous ADT, and is preferred, especially since there are subtle long-term toxicities associated with ADT. Further hormonal manipulations (including addition and withdrawal of peripheral antiandrogens, steroid synthesis inhibitors such as ketoconazole, and estrogens) can be transiently effective in selected patients with castration-resistant prostate cancer (CRPC). Androgen-dependent signalling pathways remain active in most men with CRPC and are associated with mutation, changes in expression or modulation of the androgen receptor (AR); abiraterone acetate and MDV3100 are promising drugs being evaluated in clinical trials that may lead to further hormonal response. Chemotherapy. Eventually men who progress rapidly, are symptomatic, and/or develop metastasis to visceral organs require chemotherapy. Three-weekly docetaxel with prednisone has been shown to improve survival and relieve symptoms but eventually men develop progressive disease or become intolerant to docetaxel. Multiple trials are evaluating new drugs (mainly molecular targeted agents) either given first line with docetaxel chemotherapy, or to men who have progressive disease after receiving docetaxel. Cabazitaxel was shown recently to improve survival as compared to mitoxantrone when used second line and has been approved by the United States Food and Drug Administration (FDA). Conclusion. Despite major advances, treatment of men with advanced CRPC remains a challenge both for the seeker and giver of care.

Influence of companion diagnostics on efficacy and safety of targeted anti-cancer drugs: systematic review and meta-analyses

Well-designed randomised controlled trials (RCTs) can prevent bias in the comparison of treatments and provide a sound basis for changes in clinical practice. However, the design and reporting of many RCTs can render their results of little relevance to clinical practice. In this Personal View, we discuss the limitations of RCT data and suggest some ways to improve the clinical relevance of RCTs in the everyday management of patients with cancer. RCTs should ask questions of clinical rather than commercial interest, avoid non-validated surrogate endpoints in registration trials, and have entry criteria that allow inclusion of all patients who are fit to receive treatment. Furthermore, RCTs should be reported with complete accounting of frequency and management of toxicities, and with strict guidelines to ensure freedom from bias. Premature reporting of results should be avoided. The bar for clinical benefit should be raised for drug registration, which should require publication and review of mature data from RCTs, post-marketing health outcome studies, and value-based pricing.

Clinical predictors of benefit from fulvestrant in advanced breast cancer: A Meta-analysis of randomized controlled trials

Background Companion diagnostics aim to identify patients that will respond to targeted therapies, therefore increasing the clinical efficacy of such drugs. Less is known about their influence on safety and tolerability of targeted anti-cancer agents. Methods and findings Randomized trials evaluating targeted agents for solid tumors approved by the US Food and Drug Administration since year 2000 were assessed. Odds ratios (OR) and and 95% confidence intervals (CI) were computed for treatment-related death, treatment-discontinuation related to toxicity and occurrence of any grade 3/4 adverse events (AEs). The 12 most commonly reported individual AEs were also explored. ORs were pooled in a meta-analysis. Analysis comprised 41 trials evaluating 28 targeted agents. Seventeen trials (41%) utilized companion diagnostics. Compared to control groups, targeted drugs in experimental arms were associated with increased odds of treatment discontinuation, grade 3/4 AEs, and toxic death irrespective of whether they utilized companion diagnostics or not. Compared to drugs without available companion diagnostics, agents with companion diagnostics had a lower magnitude of increased odds of treatment discontinuation (OR = 1.12 versus 1.65, p < 0.001) and grade 3/4 AEs (OR = 1.09 versus 2.10, p < 0.001), but no difference in risk of toxic death (OR = 1.40 versus 1.27, p = 0.69). Differences between agents with and without companion diagnostics were greatest for diarrhea (OR = 1.29 vs. 2.43, p < 0.001), vomiting (OR = 0.86 vs. 1.44, p = 0.005), cutaneous toxicity (OR = 1.82 vs. 3.88, p < 0.001) and neuropathy (OR = 0.64 vs. 1.60, p < 0.001). Conclusions Targeted drugs with companion diagnostics are associated with improved safety, and tolerability. Differences were most marked for gastrointestinal, cutaneous and neurological toxicity.

Duration of adjuvant trastuzumab in HER2 positive breast cancer: Overall and disease free survival results from meta-analyses of randomized controlled trials

BACKGROUND Data on the comparative efficacy of fulvestrant and other endocrine treatments are inconsistent. Clinical markers predictive of greater benefit from fulvestrant compared to the alternate endocrine agents have not been identified. METHODS We searched the literature from inception to May 2015, using MEDLINE, EMBASE, and major conference proceedings. We included randomized controlled trials (RCTs) that compared fulvestrant containing arm to either tamoxifen or an aromatase inhibitors (AI) and presented results for subgroup analyses as Hazard Ratios (HR) for Time to Progression (TTP) or Progression Free Survival (PFS). Subgroup analyses reported in at least two RCTs were included. Data were then weighted using generic inverse variance approach and pooled in meta-analysis using RevMan 5.3 software. Difference between sub-groups was tested with chi(2) statistics. RESULTS Analysis included 4 RCTs comparing fulvestrant-based therapy to AI alone and comprising 2382 patients (1190 on fulvestrant and 1192 on control arms). TTP/PFS was the primary endpoint in all included studies. Four sub-groups fulfilled our criteria. Fulvestrant was associated with greater benefit in patients with visceral metastasis (HR 0.85 vs 1.02 for no visceral disease, p for difference=0.05) and in those patients with a time to recurrence >5 years (HR 0.80 vs 1.09 for recurrence ⩽5 years, p for difference=0.02). There was no apparent difference in benefit based on age >65 years (HR 0.86 vs 0.96, p for difference=0.32) or HER2/neu status (HR 0.36 vs 0.92, p for difference=0.09). CONCLUSION Patients with advanced breast cancer with visceral involvement and longer time from diagnosis to recurrence had significantly better TTP/PFS with the use of fulvestrant. These results may have implications for selection of patients in the design of future clinical trials and to inform treatment decisions in clinical practice.