A paradigm shift in tumour response evaluation of targeted therapy: the assessment of novel drugs in exploratory clinical trials

The Potential and Emerging Role of Quantitative Imaging Biomarkers for Cancer Characterization

Simple Summary

Modern, personalized therapy approaches are increasingly changing advanced cancer into a chronic disease. Compared to imaging, novel omics methodologies in molecular biology have already achieved an individual characterization of cancerous lesions. With quantitative imaging biomarkers, analyzed by radiomics or deep learning, an imaging-based assessment of tumoral biology can be brought into clinical practice. Combining these with other non-invasive methods, e.g., liquid profiling, could allow for more individual decision making regarding therapies and applications.

Abstract

Similar to the transformation towards personalized oncology treatment, emerging techniques for evaluating oncologic imaging are fostering a transition from traditional response assessment towards more comprehensive cancer characterization via imaging. This development can be seen as key to the achievement of truly personalized and optimized cancer diagnosis and treatment. This review gives a methodological introduction for clinicians interested in the potential of quantitative imaging biomarkers, treating of radiomics models, texture visualization, convolutional neural networks and automated segmentation, in particular. Based on an introduction to these methods, clinical evidence for the corresponding imaging biomarkers—(i) dignity and etiology assessment; (ii) tumoral heterogeneity; (iii) aggressiveness and response; and (iv) targeting for biopsy and therapy—is summarized. Further requirements for the clinical implementation of these imaging biomarkers and the synergistic potential of personalized molecular cancer diagnostics and liquid profiling are discussed.

A Growth Modulation Index-Based GEISTRA Score as a New Prognostic Tool for Trabectedin Efficacy in Patients with Advanced Soft Tissue Sarcomas: A Spanish Group for Sarcoma Research (GEIS) Retrospective Study

Simple Summary

Soft tissue sarcomas (STS) are an uncommon and heterogeneous group of tumors, with scarce options for treatment in advanced cases. There is no consensus regarding which is the best treatment sequence for these patients. Although trabectedin is an approved drug for STS treatment, after progression to anthracyclines, the clinical profile of the patients that most benefit from this drug it is not defined. We have retrospectively analyzed a sample of 357 nonselected sarcoma patients from real-world experience, treated homogeneously with trabectedin, confirming and validating results from previous clinical trials and other retrospective studies. After analyzing clinical prognostic factors, we selected those which predicted a better growth modulation index (GMI > 1.33), and we defined the GEISTRA score, an easy to obtain and reproducible clinical tool, that can help us to optimize the use of trabectedin in advanced sarcoma patients.

Abstract

The aim of this study was to identify an easily reliable prognostic score that selects the subset of advanced soft tissue sarcoma (ASTS) patients with a higher benefit with trabectedin in terms of time to progression and overall survival. A retrospective series of 357 patients with ASTS treated with trabectedin as second- or further-line in 19 centers across Spain was analyzed. First, it was confirmed that patients with high growth modulation index (GMI > 1.33) were associated with the better clinical outcome. Univariate and multivariate analyses were performed to identify factors associated with a GMI > 1.33. Thus, GEISTRA score was based on metastasis free-interval (MFI ≤ 9.7 months), Karnofsky < 80%, Non L-sarcomas and better response in the previous systemic line. The median GMI was 0.82 (0–69), with 198 patients (55%) with a GMI < 1, 41 (11.5%) with a GMI 1–1.33 and 118 (33.1%) with a GMI > 1.33. The lowest GEISTRA score showed a median of time-to-progression (TTP) and overall survival (OS) of 5.7 and 19.5 months, respectively, whereas it was 1.8 and 3.1 months for TTP and OS, respectively, for the GEISTRA 4 score. This prognostic tool can contribute to better selecting candidates for trabectedin treatment in ASTS.

Community-driven development of a modified progression-free survival ratio for precision oncology

Objective

Measuring the success of molecularly guided therapies is a major challenge in precision oncology trials. A commonly used endpoint is an intra-patient progression-free survival (PFS) ratio, defined as the PFS interval associated with molecularly guided therapy (PFS2) divided by the PFS interval associated with the last prior systemic therapy (PFS1), above 1.3 or, in some studies, above 1.33 or 1.5.

Methods

To investigate if the concept of PFS ratios is in agreement with actual response evaluations by physicians, we conducted a survey among members of the MASTER (Molecularly Aided Stratification for Tumor Eradication Research) Programme of the German Cancer Consortium who were asked to classify the success of molecularly guided therapies in 194 patients enrolled in the MOSCATO 01 trial based on PFS1 and PFS2 times.

Results

A comparison of classification profiles revealed three distinct clusters of PFS benefit assessments. Only 29% of assessments were consistent with a PFS ratio threshold of 1.3, whereas the remaining 71% of participants applied a different classification scheme that did not rely on the relation between PFS times alone, but also took into account absolute PFS1 intervals. Based on these community-driven insights, we developed a modified PFS ratio that incorporates the influence of absolute PFS1 intervals on the judgement of clinical benefit by physicians. Application of the modified PFS ratio to outcome data from two recent precision oncology trials, MOSCATO 01 and WINTHER, revealed significantly improved concordance with physician-perceived clinical benefit and identified comparable proportions of patients who benefited from molecularly guided therapies.

Conclusions

The modified PFS ratio may represent a meaningful clinical endpoint that could aid in the design and interpretation of future precision oncology trials.

Perfusion MRI in hips with metal-on-metal and metal-on-polyethylene total hip arthroplasty: A pilot study

Objectives

Hips with metal-on-metal total hip arthroplasty (MoM THA) have a high rate of adverse local tissue reactions (ALTR), often associated with hypersensitivity reactions. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) measures tissue perfusion with the parameter Ktrans (volume transfer constant of contrast agent). Our purpose was 1) to evaluate the feasibility of DCE-MRI in patients with THA and 2) to compare DCE-MRI in patients with MoM bearings with metal-on-polyethylene (MoP) bearings, hypothesising that the perfusion index Ktrans in hips with MoM THA is higher than in hips with MoP THA.

Methods

In this pilot study, 16 patients with primary THA were recruited (eight MoM, eight MoP). DCE-MRI of the hip was performed at 1.5 Tesla (T). For each patient, Ktrans was computed voxel-by-voxel in all tissue lateral to the bladder. The mean Ktrans for all voxels was then calculated. These values were compared with respect to implant type and gender, and further correlated with clinical parameters.

Results

There was no significant difference between the two bearing types with both genders combined. However, dividing patients by THA bearing and gender, women with MoM bearings had the highest Ktrans values, exceeding those of women with MoP bearings (0.067 min⁻¹versus 0.053 min⁻¹; p-value < 0.05) and men with MoM bearings (0.067 min⁻¹versus 0.034 min⁻¹; p-value < 0.001). Considering only the men, patients with MoM bearings had lower Ktrans than those with MoP bearings (0.034 min⁻¹versus 0.046 min⁻¹; p < 0.05).

Conclusion

DCE-MRI is feasible to perform in tissues surrounding THA. Females with MoM THA show high Ktrans values in DCE-MRI, suggesting altered tissue perfusion kinematics which may reflect relatively greater inflammation.

Cite this article: Dr P. E. Beaule. Perfusion MRI in hips with metal-on-metal and metal-on-polyethylene total hip arthroplasty: A pilot stud. Bone Joint Res 2016;5:73–79. DOI: 10.1302/2046-3758.53.2000572.

Comparison of response evaluation criteria in solid tumours and Choi criteria for response evaluation in patients with advanced soft tissue sarcoma treated with trabectedin: a retrospective analysis

BACKGROUND

To assess the additional value of density measurement using contrast-enhancement sequences (Choi assessment) in a real-life cohort of adult soft tissue sarcoma patients treated with trabectedin.

METHODS

Eligibility criteria included adults (age ⩾18) treated between 01/2007 and 12/2011, with at least two trabectedin cycles after failure or intolerance to doxorubicin/ifosfamide. Baseline and first computed tomography (CT)-scans were centrally reviewed by an experienced radiologist.

RESULTS

The retrospective cohort consists of 134 (73 female) patients treated with trabectedin 1.5 mg/m(2) given as a 24-h infusion every 3 weeks. Patients received a median of five trabectedin cycles (range: 2-33) and the main cause of discontinuation was progressive disease (PD) (n = 105, 78.4%). Response Evaluation Criteria in Solid Tumours (RECIST) assessment was feasible in 128 (95.5%) patients, with Choi assessment performed in 92 (68.7%) patients, generally due to inadequate sequences or exclusive lung metastases. Concordance between both methods was fair (Kappa = 0.290). We identified five patients with false PD (i.e. PD according to RECIST but stable disease/partial response as per Choi). Univariate analysis did not identify any predictive factors for false PD. Median overall survival (OS) of patients with PD as per RECIST but stable disease/partial response (SD/PR) according to Choi was better than for patients with PD according to both RECIST and Choi (14 months versus 8 months; p = 0.052).

CONCLUSIONS

Choi assessment may identify patients with false PD who achieved improved efficacy outcomes, suggesting that trabectedin may delay tumour progression even in the case of non-dimensional response. Dual size and tumour density assessment may be more suitable to evaluate responses to trabectedin in sarcoma patients as well as to improve the decision-making strategies for the continuation of trabectedin therapy.

Translation in solid cancer: are size-based response criteria an anachronism?

The purpose of translation is the development of effective medicinal products based on validated science. A parallel objective is to obtain marketing authorization for the translated product. Unfortunately, in solid cancer, these two objectives are not mutually consistent as evidenced by the contrast between major advances in science and the continuing dismal record of pharmaceutical productivity. If the problem is unrelated to science, then the process of translation may require a closer examination, namely, the criteria for regulatory approval. This realization is important because, in this context, the objective of translation is regulatory approval, and science does not passively translate into useful medicinal products. Today, in solid cancer, response criteria related to tumor size are less useful than during the earlier cytotoxic drugs era; advanced imaging and biomarkers now allow for tracking of the natural history of the disease in the laboratory and the clinic. Also, it is difficult to infer clinical benefit from tumor shrinkage since it is rarely sustained. Accordingly, size-based response criteria may represent an anachronism relative to translation in solid cancer and it may be appropriate to align preclinical and clinical effort and shift the focus to local invasion and metastasis. The shift from a cancer cell-centric model to a stroma centric model offers novel opportunities not only to interupt the natural history of the disease, but also to rethink the relevance of outdated criteria of clinical response. Current evidence favors the opinion that, in solid cancer, a different, broader, and contextual approach may lead to interventions that could delay local invasion and metastasis. All elements supporting this shift, especially advanced imaging, are in place.

What is an active regimen in carcinoma of unknown primary sites? Analysis of correlation between activity endpoints reported in phase II trials. Correlation of activity endpoints in phase II trials

BACKGROUND

The choice of the activity endpoint is crucial when designing phase II screening trials. This choice is usually guided by convention, but the level of evidence for picking-up one of them is limited.

METHODS

We have analysed the phase II trials in carcinoma of unknown primary patients (CUP; 48 strata). We calculated the Pearson correlation coefficient using weighted linear regression to measure the degree of association between the different available activity endpoints (Best objective response - BORR, best tumour control rate - BTCR, 3- and 6-month progression-free rates, 3- and 6-month PFR and median progression-free survival). We also explored the correlation between these endpoints and OS.

RESULTS

All activity endpoints were strongly correlated in CUP studies; all of these endpoints were strongly correlated with OS. The median BORR across the studies was 30%. Positive trials defined by BORR ≥ 30% were associated with statistically longer PFS (4.8 versus 3.7 months, P = 0.013) and OS (10.0 versus 8.0, P = 0.0007).

DISCUSSION

In phase II studies with CUP patients, BORR and the threshold of BORR > 30% for defining promising drug appears adequate.

Correlation between overall survival and growth modulation index in pre-treated sarcoma patients: a study from the French Sarcoma Group

BACKGROUND

Growth modulation index (GMI), the ratio of two times to progression measured in patients receiving two successive treatments (GMI = TTP2/TTP1), has been proposed as a criterion of phase II clinical trials. Nevertheless, its use has been limited until now.

PATIENTS AND METHODS

We carried out a retrospective multicentre study in soft tissue sarcoma patients receiving a second-line treatment after doxorubicin-based regimens to evaluate the link between overall survival and GMI. Second-line treatments were classified as 'active' according to the EORTC-STBSG criteria (3-month progression-free rate >40% or 6-month PFR >14%). Comparisons used chi-squared and log-rank tests.

RESULTS

The population consisted in 106 men and 121 women, 110 patients (48%) received 'active drugs'. Median OS from the second-line start was 317 days. Sixty-nine patients experienced GMI >1.33 (30.4%). Treatments with 'active drug' were not associated with OS improvement: 490 versus 407 days (P = 0.524). Median OS was highly correlated with GMI: 324, 302 and 710 days with GMI <1, GMI = [1.00-1.33], and GMI >1.33, respectively (P < 0.0001). In logistic regression analysis, the sole predictive factor was the number of doxorubicin-based chemotherapy cycles.

CONCLUSION

GMI seems to be an interesting end point that provides additional information compared with classical criteria. GMI >1.33 is associated with significant OS improvement.

Activity endpoints reported in soft tissue sarcoma phase II trials: quality of reported endpoints and correlation with overall survival

BACKGROUND

Despite extensive research over the past 3 decades, few investigational drugs are considered as promising and these drugs failed to improve overall survival. Therefore we performed a systematic review of the literature to improve our understanding of the reasons that explain these failures.

METHODS

We reviewed 53 phase II trial reports that investigated new treatments in patients with advanced soft tissue sarcoma from 1999 to 2011. We critically reviewed the selected primary endpoint used in these trials.

RESULTS

Forty percent of trials were not interpretable because of major inherent methodological flaws. Only 3 primary endpoints were correlated with median overall survival (mOS): 3- and 6-month progression free rates and median progression-free survival. Nevertheless, the mOS was not significantly higher in the cases of active drugs.

DISCUSSION

We need to improve the definition of primary active endpoints and develop better designs for future trials. The current definition of promising drugs must be refined.

Growth modulation index as metric of clinical benefit assessment among advanced soft tissue sarcoma patients receiving trabectedin as a salvage therapy

BACKGROUND

The growth modulation index (GMI) is the ratio of time to progression with the nth line (TTP(n)) of therapy to the TTP(n)(-1) with the n-1th line. GMI >1.33 is considered as a sign of activity in phase II trials.

PATIENTS AND METHODS

This retrospective analysis evaluated the concordance between the GMI and the efficacy outcomes in 279 patients with advanced soft tissue sarcoma (ASTS) treated with trabectedin 1.5 mg/m² (24-h infusion every 3 weeks) in four phase II trials.

RESULTS

One hundred and forty-two (51%) patients received one prior line and 137 ≥ 2 lines. The median TTP(n) was 2.8 months (range 0.2-26.8), whereas the median TTP(n)(-1) was 4.0 months (0.3-79.5). The median GMI was 0.6 (0.0-14.4). Overall, 177 patients (63%) had a GMI <1; 21 (8%) a GMI equal to 1-1.33 and 81 (29%) a GMI >1.33, which correlated with the median overall survival in those patients (9.1, 13.9 and 23.8 months, respectively, P = 0.0005). A high concordance rate between the GMI and response rate (P < 0.0001) and progression-free survival (PFS, P < 0.0001) was observed. Good performance status (PS) was the only factor associated with GMI >1.33 (PS = 0; P < 0.04).

CONCLUSIONS

A high GMI was associated with favorable efficacy outcomes in patients treated with trabectedin. Further research is needed to assess GMI as an indicator in this setting.

Predictive value of clinical judgment of tumour progression in phase II trials

Background

The diagnosis of tumour progression or progressive disease (PD) is a key element for designing and interpreting contemporary phase II trials. In some cases, PD is stated by the physician and is not formally confirmed by imaging.

Purpose

In this study, we intend to analyze the value of the PD based on clinical judgment and the risk of overestimating the occurrence of PD by clinical judgment.

Methods

We have conducted a single-centre retrospective study to analyse the diagnostic accuracy of this clinical judgment compared to planned imaging including all patients enrolled in our institution in phase II trials investigating systemic treatments for advanced solid tumours between January 2008 and November 2010.

Results

The positive predictive value (PPV) and the specificity of clinical judgment of PD was very high (>90%).

Conclusions

According to this study, the clinical judgment of PD is highly predictive of radiological PD as assessed, for example, by RECIST. Physicians do not overestimate PD occurence. Clinical judgment of PD could be taken into account in the definition of PD.