The Value of Progression-Free Survival as a Treatment End Point Among Patients With Advanced Cancer: A Systematic Review and Qualitative Assessment of the Literature

Measurable residual disease (MRD)-testing in haematological cancers: A giant leap forward or sideways?

Measurable residual disease (MRD)-testing is used in many haematological cancers to estimate relapse risk and to direct therapy. Sometimes MRD-test results are used for regulatory approval. However, some people including regulators wrongfully believe results of MRD-testing are highly accurate and of proven efficacy in directing therapy. We review MRD-testing technologies and evaluate the accuracy of MRD-testing for predicting relapse and the strength of evidence supporting efficacy of MRD-guided therapy. We show that at the individual level MRD-test results are often an inaccurate relapse predictor. Also, no convincing data indicate that increasing therapy-intensity based on a positive MRD-test reduces relapse risk or improves survival. We caution against adjusting therapy-intensity based solely on results of MRD-testing.

Patients' attitudes and preferences toward delayed disease progression in the absence of improved survival

BACKGROUND

Cancer patients' attitudes toward progression-free survival (PFS) gains offered by treatment are not well understood, particularly in the absence of overall survival (OS) gains. The objectives were to describe patients' willingness to accept treatment that offers PFS gains without OS gains, to compare these findings with treatments offering OS gains, and to qualitatively summarize patients' reasons for their preferences.

METHODS

A multicenter, cross-sectional, convergent mixed-methods study design recruited patients who had received at least 3 months of systemic therapy for incurable solid tumors. A treatment trade-off exercise determined the gains in imaging PFS that patients require to prefer additional systemic treatment for a scenario of a newly diagnosed, asymptomatic, incurable abdominal tumor. A qualitative, descriptive, thematic analysis explored factors influencing patients' decisions, and a narrative method integrated the quantitative and qualitative findings.

RESULTS

In total, 100 patients participated (63% were older than 60 years of age). If additional treatment with added toxicity offered no OS advantage, 17% would prefer it for no PFS benefit; 26% for some PFS benefit (range, 3-9 months), whereas 51% would decline it regardless of PFS benefit. Similarly, 71% preferred additional treatment offering a 6-month OS advantage dependent on described toxicity levels (P = .03). A spectrum of reasons for these preferences reflected the complexity of participants' attitudes and values.

CONCLUSIONS

Prolongation of time to progression was not universally valued. Most patients did not prefer treatments that negatively affect quality of life for PFS gains alone. Implications for individual decision making, policy, and trials research are discussed.

Difference in Efficacy and Safety of Anti-CD19 Chimeric Antigen Receptor T-Cell Therapy Containing 4-1BB and CD28 Co-Stimulatory Domains for B-Cell Acute Lymphoblastic Leukemia

This study quantified the differences in the efficacy and safety of different stimulation domains of anti-CD19 chimeric antigen receptor (CAR) T therapy for B-cell acute lymphoblastic leukemia (B-ALL). Clinical trials related to anti-CD19 CAR T-cell therapy for B-ALL were searched in public databases from database inception to 13 November 2021. The differences in overall survival (OS) and progression-free survival (PFS) of B-ALL patients treated with anti-CAR T-cell therapy containing 4-1BB and CD28 co-stimulatory domains were compared by establishing a parametric survival function. The overall remission rate (ORR), the proportion of people with minimal residual disease (MRD)-negative complete remission (CR), the incidence of cytokine release syndrome (CRS), and the neurotoxicity across different co-stimulatory domains was assessed using a random-effects model. The correlation between the ORR, MRD-negative CR, PFS, and OS was tested. The results showed that the median OS of anti-CAR T-cell treatment containing 4-1BB and CD28 co-stimulatory domains was 15.0 months (95% CI: 11.0-20.0) and 8.5 months (95% CI: 5.0-14.0), and the median PFS was 7.0 months (95% CI: 4.0-11.5) and 3.0 months (95% CI: 1.5-7.0), respectively. Anti-CD19 CAR T-cells in the 4-1BB co-stimulatory domain showed superior benefits in patients who achieved ORR. The incidence of neurotoxicity was significantly higher in the CD28 co-stimulatory domain of anti-CD19 CAR T-cells than in the 4-1BB co-stimulatory domain. In addition, the ORR and MRD-negative CR were strongly correlated with OS and PFS, and PFS and OS were strongly correlated. The 4-1BB co-stimulatory domain suggested a better benefit-risk ratio than the CD28 co-stimulatory domain in B-ALL.

Quantitative Benefit-Risk Assessment in Medical Product Decision Making: A Good Practices Report of an ISPOR Task Force

Benefit-risk assessment is commonly conducted by drug and medical device developers and regulators, to evaluate and communicate issues around benefit-risk balance of medical products. Quantitative benefit-risk assessment (qBRA) is a set of techniques that incorporate explicit outcome weighting within a formal analysis to evaluate the benefit-risk balance. This report describes emerging good practices for the 5 main steps of developing qBRAs based on the multicriteria decision analysis process. First, research question formulation needs to identify the needs of decision makers and requirements for preference data and specify the role of external experts. Second, the formal analysis model should be developed by selecting benefit and safety endpoints while eliminating double counting and considering attribute value dependence. Third, preference elicitation method needs to be chosen, attributes framed appropriately within the elicitation instrument, and quality of the data should be evaluated. Fourth, analysis may need to normalize the preference weights, base-case and sensitivity analyses should be conducted, and the effect of preference heterogeneity analyzed. Finally, results should be communicated efficiently to decision makers and other stakeholders. In addition to detailed recommendations, we provide a checklist for reporting qBRAs developed through a Delphi process conducted with 34 experts.

Communication of anticancer drug benefits and related uncertainties to patients and clinicians: document analysis of regulated information on prescription drugs in Europe

OBJECTIVE

To evaluate the frequency with which relevant and accurate information about the benefits and related uncertainties of anticancer drugs are communicated to patients and clinicians in regulated information sources in Europe.

DESIGN

Document content analysis.

SETTING

European Medicines Agency.

PARTICIPANTS

Anticancer drugs granted a first marketing authorisation by the European Medicines Agency, 2017-19.

MAIN OUTCOME MEASURES

Whether written information on a product addressed patients' commonly asked questions about: who and what the drug is used for; how the drug was studied; types of drug benefit expected; and the extent of weak, uncertain, or missing evidence for drug benefits. Information on drug benefits in written sources for clinicians (summaries of product characteristics), patients (patient information leaflets), and the public (public summaries) was compared with information reported in regulatory assessment documents (European public assessment reports).

RESULTS

29 anticancer drugs that received a first marketing authorisation for 32 separate cancer indications in 2017-19 were included. General information about the drug (including information on approved indications and how the drug works) was frequently reported across regulated information sources aimed at both clinicians and patients. Nearly all summaries of product characteristics communicated full information to clinicians about the number and design of the main studies, the control arm (if any), study sample size, and primary measures of drug benefit. None of the patient information leaflets communicated information to patients about how drugs were studied. 31 (97%) summaries of product characteristics and 25 (78%) public summaries contained information about drug benefits that was accurate and consistent with information in regulatory assessment documents. The presence or absence of evidence that a drug extended survival was reported in 23 (72%) summaries of product characteristics and four (13%) public summaries. None of the patient information leaflets communicated information about the drug benefits that patients might expect based on study findings. Scientific concerns about the reliability of evidence on drug benefits, which were raised by European regulatory assessors for almost all drugs in the study sample, were rarely communicated to clinicians, patients, or the public.

CONCLUSIONS

The findings of this study highlight the need to improve the communication of the benefits and related uncertainties of anticancer drugs in regulated information sources in Europe to support evidence informed decision making by patients and their clinicians.

Building Awareness of Diagnosis Together: Ambiguity During Progression-Free Survival Experienced by Patients With Lung Cancer and Caregivers in China

BACKGROUND

Lung cancer, as a multistep and multifactorial disease, is among the most fatal cancers worldwide. As new therapies are developed and early screening increases, patients tend to experience progression-free survival (PFS) as a coexistence of living and dying simultaneously.

OBJECTIVE

The aim of this study was to explore the awareness context experienced by Chinese elderly patients and family members.

METHODS

Interviews were conducted with 20 interviewees, including 13 elderly patients with lung cancer and 7 caregivers that were recruited using purposive sampling. Semistructured, face-to-face, in-depth interviews were conducted using a qualitative descriptive approach.

RESULTS

Ambiguity was commonly experienced by patients with lung cancer with PFS. Three themes emerged from the data analysis: "ambiguity in cancer diagnosis," "ambiguity in prognostic awareness," and "ambiguity in identity." In this case, ambiguity refers to a situation or context in which patients are uncertain about whether there will be a recurrence of their cancer and when it might occur.

CONCLUSIONS

The findings highlighted that patients experienced ambiguity in response to unclear diagnoses, uncertain prognoses, and identity crises during PFS.

IMPLICATIONS FOR PRACTICE

Healthcare teams should be equipped with psychosocial knowledge and communication skills to manage ambiguity in diagnosis and prognosis for patients with PFS.

The Importance of Disease-Free Survival as a Clinical Trial Endpoint: A Qualitative Study Among Canadian Survivors of Lung Cancer

BACKGROUND

In lung cancer trials, overall survival is a well-validated and widely used endpoint; yet, in the context of adjuvant or curative intent treatments, disease-free survival (DFS) may be a better indicator of transformative patient outcomes. Although use of DFS is growing, patient perceptions of its relevance have not been established.

OBJECTIVE

We aimed to understand the importance of DFS as a trial endpoint, from the perspective of survivors of lung cancer.

METHODS

Web-based qualitative interviews were conducted with Canadian survivors of stage Ib-IIIa lung cancer. Participants described their experiences of cancer diagnosis and treatment, including their treatment goals and priorities. Participants then provided their perspectives on DFS and overall survival, and how well each aligned with their treatment priorities. Thematic analysis was used to explore patterns in responses.

RESULTS

Among the 18 participants (mean age, 64 years), 83% were female, most (89%) had received surgery, and 56% received chemotherapy. Most participants viewed DFS as an intrinsically meaningful treatment outcome, for reasons such as alignment with treatment goals, and the perception that DFS would help maintain a high quality of life. One individual was interested in DFS only as a potential surrogate for overall survival. Participants desired access to new treatments that improve DFS and emphasized this within the context of promoting patient agency in treatment decision making.

CONCLUSIONS

These findings suggest DFS is a meaningful endpoint from the perspective of survivors of lung cancer; and may help inform decisions regarding regulatory approval and reimbursement of new treatments based on DFS data.

Patient Preferences for Attributes of Chemotherapy for Lung Cancer: Discrete Choice Experiment Study in Japan

Our study objective was to determine lung cancer chemotherapy attributes that are important to patients in Japan. A discrete choice experiment survey in an anonymous web-based questionnaire format with a reward was completed by 200 lung cancer patients in Japan from November 25, 2019, to November 27, 2019. The relative importance of patient preferences for each attribute was estimated using a conditional logit model. A hierarchical Bayesian logit model was also used to estimate the impact of each demographic characteristic on the relative importance of each attribute. Of the 200 respondents, 191 with consistent responses were included in the analysis. In their preference, overall survival was the most important, followed by diarrhea, nausea, rash, bone marrow suppression (BMS), progression-free survival, fatigue, interstitial lung disease, frequency of administration, and duration of administration. The preferences were influenced by demographic characteristics (e.g., gender and age) and disease background (e.g., cancer type and stage). Interestingly, the experience of cancer drug therapies and adverse events had a substantial impact on the hypothetical drug preferences. For the Japanese lung cancer patients, improved survival was the most important attribute that influenced their preference for chemotherapy, followed by adverse events, including diarrhea, nausea, rash, and BMS. The preferences varied depending on the patient’s demographic and experience. As drug attributes can affect patient preferences, pharmaceutical companies should be aware of the patient preferences and develop drugs that respond to segmented market needs.

Are Quality of Randomized Clinical Trials and ESMO-Magnitude of Clinical Benefit Scale Two Sides of the Same Coin, to Grade Recommendations for Drug Approval?

The approval of a new drug for cancer treatment by the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA) is based on positive, well-designed randomized phase III clinical trials (RCTs). However, not all of them are analyzed to support the recommendations. For this reason, there are different scales to quantify and evaluate the quality of RCTs and the magnitude of the clinical benefits of new drugs for treating solid tumors. In this review, we discuss the value of the progression-free survival (PFS) as an endpoint in RCTs and the concordance between it and the overall survival (OS) as a measure of the quality of clinical trial designs. We summarize and analyze the different scales to evaluate the clinical benefits of new drugs such as the The American Society of Clinical Oncology value framework (ASCO-VF-NHB16) and European Society for Medical Oncology Magnitude of Clinical Benefit Scale (ESMO-MCBS) and the concordance between them, focusing on metastatic colorectal cancer (mCRC). We propose several definitions that would help to evaluate the quality of RCT, the magnitude of clinical benefit and the appropriate approval of new drugs in oncology.

Evaluation of Selective Outcome Reporting Bias in Efficacy Endpoints in Print and Television Advertisements for Oncology Drugs

IMPORTANCE

Selective outcome reporting bias in oncology drug advertisements may encourage misconceptions about a drug's efficacy profile.

OBJECTIVE

We sought to determine the rates of selective outcome reporting in published cancer clinical trials and in television and print advertisements for anticancer medications. We also quantified the number of advertisements that did not include or cite any studies with mature overall survival (OS) data (i.e., data with all required patient events for final analysis).

DESIGN/SETTING/PARTICIPANTS

We conducted a cross-sectional investigation of advertisements uploaded to the AdPharm Database (repository of pharmaceutical advertisements); the clinical trials supporting the ads; and the trial registrations associated with the trials. Data were extracted by two investigators who were blinded to each other's data.

MAIN OUTCOME MEASURES

The first co-primary objective was to investigate selective outcome reporting between trial registrations and published trials. The second co-primary objective was to investigate selective outcome reporting between the same published trials and drug advertisements.

RESULTS

We included 74 advertisements and 48 clinical trials. Print ads were the most common (n = 66), and most print advertisements were targeted to health care providers (n = 55, 83.3%). Overall, 41/48 (85.4%) trials were registered prior to study enrollment, and 41/48 (85.4%) did not deviate from the registered primary endpoints. Across all advertisements (n = 74), statistically significant endpoints were more often reported (unadjusted risk ratio [uRR] 1.26; 95% confidence interval [CI] (1.14-1.40)) and 22/55 (40.0%) advertisements cited trials with immature overall survival data (i.e., data without the required number of events for final analysis).

CONCLUSIONS

In our sample, statistically significant endpoints were more commonly reported than nonsignificant endpoints. Immature endpoints (those analyzed before the required number of accrued patient events) were often reported. By reporting only significant endpoints and those that are immature, advertisers may encourage misconceptions about a drug's efficacy profile.

Progression-free survival is a suboptimal predictor for overall survival among metastatic solid tumour clinical trials

BACKGROUND

The use of overall survival (OS) as the gold standard primary end-point (PEP) in metastatic oncologic randomised controlled trials (RCTs) has declined in favour of progression-free survival (PFS) without a complete understanding of the degree to which PFS reliably predicts for OS.

METHODS

Using ClinicalTrials.gov, we identified 1239 phase III oncologic RCTs, 260 of which were metastatic solid tumour trials with a superiority-design investigating a therapeutic intervention by using either a PFS or OS PEP. Each individual trial was reviewed to quantify RCT design factors and disease-related outcomes.

RESULTS

A total of 172,133 patients were enrolled from the year 1999 to 2015 in RCTs that used PFS (56.2%, 146/260) or OS (43.8%, 114/260) as the PEP. PFS trials were more likely to restrict patient eligibility by using molecular criteria (15.1% versus 4.4%, p = 0.005) use targeted therapy (80.1% versus 67.5%, p = 0.048), accrue fewer patients (median 495 versus 619, p = 0.03), and successfully meet the trial PEP (66.9% versus 33.3%, p < 0.0001). On multiple binary logistic regression analysis, factors that predicted for PFS or OS PEP trial success included choice of PFS PEP (p < 0.0001), molecular profile restriction (p = 0.02) and single agent therapy (p = 0.02). Notably, there was only a 38% (31/82) conversion rate of positive PFS-to-OS benefit; lack of industry sponsorship predicted for PFS-to-OS signal conversion (80.0% without industry sponsorship versus 35.1% with industry sponsorship, p = 0.045).

CONCLUSIONS

A PFS PEP has suboptimal positive predictive value for OS among phase III metastatic solid tumour RCTs. Regulatory agency decisions should be judicious in using PFS results as the primary basis for approval.

Association of progression-free or event-free survival with overall survival in diffuse large B-cell lymphoma after immunochemotherapy: a systematic review

To investigate progression-free survival (PFS) and event-free survival (EFS) as early efficacy endpoints in diffuse large B-cell lymphoma (DLBCL), this systematic review included phase III randomized controlled trials (RCTs), phase II trials, and retrospective studies in newly diagnosed DLBCL receiving rituximab-containing chemotherapy through databases search up to 2019. Quality control was performed, where studies with high risk of bias were excluded. Prediction models were first established using the RCTs, and then externally validated in the phase II and retrospective populations. Trial-level surrogacy analysis was conducted by correlating the logarithmic (log) hazard ratio (HR) for PFS or EFS and log HR for OS. Correlation analysis at treatment arm-level was performed between 1-, 2-, 3-, and 5-year PFS or EFS rates and 5-year OS. The correlation was evaluated using the Pearson correlation coefficient r in weighted linear regression, with weight equal to patient size. Sensitivity analyses were performed to assess the consistency of predictive model by leaving one subgroup of trials out at a time. Twenty-six phase III RCTs, 4 phase II trials and 47 retrospective studies were included. In trial-level surrogacy, PFS (r, 0.772; 95% confidence interval [CI], 0.471-0.913) or EFS (r, 0.838; 95% CI, 0.625-0.938) were associated with OS. For rituximab immunochemotherapy treatment arms in RCTs, there was a linear correlation between 1 and 5-year PFS (r, 0.813-0.873) or EFS (r, 0.853-0.931) and 5-year OS. Sensitivity analysis demonstrated reasonable overall consistency. The correlation between PFS and OS was externally validated using independent phase II, and retrospective data (r, 0.795-0.897). We recommend PFS and EFS as earlier efficacy endpoints in patients with DLBCL primarily treated with rituximab-containing immunochemotherapy.

Patient familiarity with, understanding of, and preferences for clinical trial endpoints and terminology

BACKGROUND

Although there is increased attention to designing and explaining clinical trials in ways that are clinically meaningful for patients, there is limited information on patient preferences, understanding, and perceptions of this content.

METHODS

Maximum difference scaling (MaxDiff) methodology was used to develop a survey for assessing patients' understanding of 19 clinical terms and perceived importance of 9 endpoint surrogate phrases used in clinical trials and consent forms. The survey was administered electronically to individuals with metastatic breast cancer affiliated with the Metastatic Breast Cancer Alliance. Analyses were performed using Bayesian P values with statistical software.

RESULTS

Among 503 respondents, 77% had a college degree, 70% were diagnosed with metastatic disease ≥2 years before survey completion, and 77% had received ≥2 lines of systemic therapy. Less than 35% of respondents reported understanding "fairly well" the terms symptomatic progression, duration of disease control, time to treatment cessation, and endpoints. Income level and time since onset of metastatic disease correlated with comprehension. Patients who had received ≥6 lines of therapy perceived that time until serious side effects (P < .001) and time on therapy (P < .001) were more important compared with those who had received only 1 line of therapy. Positively phrased parameters were associated with increased perceived importance.

CONCLUSIONS

Even among educated, heavily pretreated patients, many commonly used clinical research terms are poorly understood. Comprehension and the perceived importance of trial endpoints vary over the course of disease. These observations may inform the design, discussion, and reporting of clinical trials.

Analysis of Patient Preferences in Lung Cancer - Estimating Acceptable Tradeoffs Between Treatment Benefit and Side Effects

OBJECTIVE

Increased treatment options and longer survival for lung cancer have generated increased interest in patient preferences. Previous studies of patient preferences in lung cancer have not fully explored preference heterogeneity. We demonstrate a method to explore preference heterogeneity in the willingness of patients with lung cancer and caregivers to trade progression-free survival (PFS) with side effects.

PATIENTS AND METHODS

Patients and caregivers attending a national lung cancer meeting completed a discrete-choice experiment (DCE) designed through a collaboration with patients. Participants answered 13 choice tasks described across PFS, short-term side effects, and four long-term side effects. Side effects were coded as a one-level change in severity (none-mild, mild-moderate, or moderate-severe). A mixed logit model in willingness-to-pay space estimated preference heterogeneity in acceptable tradeoffs (time equivalents) between PFS and side effects. The study was reported following quality indicators from the United States Food and Drug Administration's patient preference guidance.

RESULTS

A total of 87 patients and 24 caregivers participated in the DCE. Participants would trade 3.7 month PFS (95% CI (CI): 3.3-4.1) for less severe functional long-term treatment side effects, 2.3 months for less severe physical long-term effects (CI: 1.9-2.8) and cognitive long-term effects (CI: 1.8-2.8), 0.9 months (CI: 0.4-1.4) for less severe emotional long-term effects, and 1.8 months (CI: 1.4-2.3) for less severe short-term side effects. Most participants (90%) would accept treatment with more severe functional long-term effects for 8.4 additional month PFS.

CONCLUSION

Participants would trade PFS for changes in short-term side effects and long-term side effects, although preference heterogeneity existed. Lung cancer treatments that offer less PFS but also less severe side effects might be acceptable to some patients.