Randomized controlled trials in the era of molecular oncology: methodology, biomarkers, and end points

BACKGROUND

We previously reported metrics of systemic therapy randomized controlled trials (RCTs) in breast cancer, colorectal cancer (CRC), and non-small-cell lung cancer (NSCLC) published 1975-2004. To evaluate trends in the era of targeted therapies (TT), we have repeated a similar analysis of RCTs published 2005-2009.

METHODS

A search for phase III RCTs of systemic agents published in five major journals 2005-2009 was carried out. Trials were classified as TT if they involved any non-hormonal targeted agent. We extracted data regarding biomarker use. Integral biomarkers were defined as tests used to determine eligibility, stratification, or allocation. Descriptive statistics were used to analyze trends over time.

RESULTS

One hundred and thirty-seven eligible RCTs were evaluated. Compared with 1995-2004, the number (17-27 RCTs/year) and size (median sample size 446-722, P < 0.001) of RCTs increased. The proportion of RCTs evaluating TT increased from 4% (7/167) to 29% (40/137) (P < 0.001). There was an increase in the proportion of trials with financial support from industry [57% (95/167) to 78% (107/137), P = 0.001]. Biomarkers were included in 58% (80/137) of RCTs; integral biomarkers were included in 36% (49/137) of trials. Among the 49 RCTs using integral biomarkers, 40 (82%) used HER2 and/or ER/PR status in studies of breast cancer.

CONCLUSIONS

RCTs published in 2005-2009 are larger, more likely to evaluate TT, and be supported by industry. Biomarkers may be increasingly used, but the most common use relates to traditional use of ER/PR and evolving use of HER2 in breast cancer RCTs.

Triclosan antagonizes fluconazole activity against Candida albicans

Triclosan is a broad-spectrum antimicrobial compound commonly used in oral hygiene products. Investigation of its activity against Candida albicans showed that triclosan was fungicidal at concentrations of 16 mg/L. However, at subinhibitory concentrations (0.5-2 mg/L), triclosan antagonized the activity of fluconazole. Although triclosan induced CDR1 expression in C. albicans, antagonism was still observed in cdr1Δ and cdr2Δ strains. Triclosan did not affect fluconazole uptake or alter total membrane sterol content, but did induce the expression of FAS1 and FAS2, indicating that its mode of action may involve inhibition of fatty acid synthesis, as it does in prokaryotes. However, FAS2 mutants did not exhibit increased susceptibility to triclosan, and overexpression of both FAS1 and FAS2 alleles did not alter triclosan susceptibility. Unexpectedly, the antagonistic effect was specific for C. albicans under hypha-inducing conditions and was absent in the non-filamentous efg1Δ strain. This antagonism may be due to the membranotropic activity of triclosan and the unique composition of hyphal membranes.

Development and initial psychometric evaluation of the Stroke Arm Ladder – a measure of upper extremity function post stroke*

Objective: To develop an adaptive measure, the Stroke Arm Ladder, to parsimoniously quantify upper extremity function post stroke.

Setting: Various studies conducted in Montreal and elsewhere in Canada.

Subjects: A total of 4058 persons with stroke who participated in various studies were assessed on different occasions post stroke. Assessments spanned from 3 days to 1 year post stroke.

Main measures: A calibrated bank containing 49 items from tests and indices designed to assess global motor recovery of the upper extremity, upper extremity function and activities involving the upper extremity was used. Data including all testing occasions were analysed to test whether they adhered to the expectations of the Rasch partial credit model and whether item hierarchy remained stable across testing occasions.

Results: Fifteen items did not meet the requirements of the Rasch model and were deleted. An adaptive measure of upper extremity function, the Stroke Arm Ladder, containing 34 items was created. The easiest item was partially executing the bilateral task of tying a scarf around one’s neck, while the hardest item was being able to transfer more than 60 blocks on the Box and Block Test. The items’ difficulty thresholds cover a wide range of difficulty levels from −7.4 to 6.2 and the global fit statistics (χ2: 331; probability: 0.18), confirmed content validity.

Conclusion: The Stroke Arm Ladder demonstrates adequate initial psychometric properties. Further testing of the measure in its adaptive format is necessary before it can be used clinically.

A measure of early physical functioning (EPF) post-stroke

OBJECTIVE

To develop a comprehensive measure of Early Physical Functioning (EPF) post-stroke quantified through Rasch analysis and conceptualized using the International Classification of Functioning Disability and Health (ICF).

DESIGN

An observational cohort study.

SUBJECTS

A cohort of 262 subjects (mean age 71.6 (standard deviation 12.5) years) hospitalized post-acute stroke.

METHODS

Functional assessments were made within 3 days of stroke with items from valid and reliable indices commonly utilized to evaluate stroke survivors. Information on important variables was also collected. Principal component and Rasch analysis confirmed the factor structure, and dimensionality of the measure. Rasch analysis combined items across ICF components to develop the measure. Items were deleted iteratively, those retained fit the model and were related to the construct; reliability and validity were assessed.

RESULTS

A 38-item unidimensional measure of the EPF met all Rasch model requirements. The item difficulty matched the person ability (mean person measure: -0.31; standard error 0.37 logits), reliability of the person-item-hierarchy was excellent at 0.97. Initial validity was adequate.

CONCLUSION

The 38-item EPF measure was developed. It expands the range of assessment post acute stroke; it covers a broad spectrum of difficulty with good initial psychometric properties that, once revalidated, can assist in planning and evaluating early interventions.