A comparison of the outcomes of pulmonary versus extrapulmonary extensive-stage small cell carcinoma

BACKGROUND

Extrapulmonary small cell carcinomas (EPSCCs) are rare cancers, comprising 0.1-0.4% of all cancers. The scarcity of EPSCC studies has led current treatment strategies to be extrapolated from small cell lung cancer (SCLC), justified by analogous histological and clinical features.

AIMS

We conducted a retrospective cohort study comparing the outcomes of extensive-stage (ES) SCLC and EPSCC.

METHODS

Patients diagnosed with ES SCLC or EPSCC between 2010 and 2020 from four hospitals in Sydney were identified. Patients who received active treatment and best supportive care were included. The primary endpoint was overall survival (OS), and secondary endpoints were progression-free survival (PFS) and overall response rates (ORRs).

RESULTS

Three hundred and eighty-four patients were included (43 EPSCC vs. 340 SCLC). EPSCC were of genitourinary (n = 15), unknown primary (n = 13) and gastrointestinal (n = 12) origin. Treatment modalities for EPSCC compared to SCLC included palliative chemotherapy (56% vs 73%), palliative radiotherapy (47% vs 59%) and consolidation chest radiotherapy (10% of SCLC). Overall, median OS was 6.4 versus 7 months for EPSCC versus SCLC respectively, but highest in prostate EPSCC (25.6 months). Of those who received chemotherapy (22 EPSCC vs 233 SCLC), median OS was 10.4 versus 8.4 months (HR OS 0.81, 95% confidence interval (CI): 0.5-1.31, P = 0.38); PFS was 5.4 versus 5.5 months (HR PFS 0.93, 95% CI: 0.58-1.46, P = 0.74) and ORR were 73% versus 68%.

CONCLUSIONS

EPSCC and SCLC appeared to have comparable OS and treatment outcomes. However, the wide range of OS in EPSCC highlights the need for an improved understanding of its genomics to explore alternative therapeutics.

Validity and Efficiency of Progression-Free Survival-2 as a Surrogate End Point for Overall Survival in Advanced Cancer Randomized Trials

PURPOSE

Progression-free survival (PFS)-2, defined as the time from randomization to progression on second-line therapy, is potentially a more reliable surrogate than PFS for overall survival (OS), but will require longer follow-up and a larger sample size. We sought to compare the validity and efficiency, defined as proportional increase in follow-up time and sample size, of PFS-2 to PFS.

METHODS

We performed an electronic search to identify randomized trials of advanced solid tumors reporting PFS, PFS-2, and OS as prespecified end points. Only studies that had protocols that defined measurement of PFS-2 and follow-up for patients after first disease progression were included. We compared correlations in the relative treatment effect for OS with PFS and PFS-2. We reconstructed individual patient data from survival curves to estimate time to statistical significance (TSS) of the relative treatment effect. We further computed the sample size (person-year [PY] follow-up) required to reach statistical significance.

RESULTS

Across the 42 analysis units and 21,255 patients, the correlation of the relative treatment effect between OS and PFS-2, r, was 0.70 (95% CI, 0.41 to 0.80) and r = 0.46 (95% CI, 0.26 to 0.74) for OS and PFS. The median differences in TSS between OS with PFS, OS with PFS-2, and PFS with PFS-2 were 16.59 (95% CI, 4.48 to not reached [NR]), 10.0 (95% CI, 2.2 to NR), and 4.31 (95% CI, 2.92 to 13.13) months, respectively. The median difference in PYs required to reach statistical significance for PFS-2 over PFS was 156 (95% CI, 82 to 500) PYs, equivalent to an estimated median 12.7% increase in PYs.

CONCLUSION

PFS-2 offers improved correlation with OS than PFS with a modest increase in follow-up time and sample size. PFS-2 should be considered as a primary end point in future trials of advanced cancers.

Validity and efficiency of progression-free survival (PFS)-2 as a surrogate endpoint for overall survival (OS) in advanced cancer

6518

Background: PFS is used widely as a primary endpoint in oncology trials and as a surrogate for OS. PFS-2, defined as time from randomization to progression on second line therapy, is potentially a more reliable surrogate than PFS but requires additional follow-up time. We evaluated the validity and efficiency of PFS-2 as a surrogate endpoint for OS and compared its performance with PFS. Methods: We performed an electronic search to identify randomized trials of advanced solid tumors reporting on PFS, PFS-2 and OS as pre-specified endpoints. We compared the correlations in the relative treatment effect for OS with PFS and PFS-2. We extracted data from Kaplan-Meier survival curves to create individual patient data to estimate time to statistical significance (TSS), defined as logrank P < 0.05. We further computed the samples size (person-year follow-up) required to reach statistical significance and assessed for the effect of survival post-progression (SPP). If trials failed to reach statistical significance for a particular endpoint, the maximal follow-up time was used. Results: Our study consisted of 39 analysis units with 20714 patients. Correlations of the OS treatment effect with the PFS and PFS-2 treatment effects were r= 0.12 (95% CI 0.00-0.13) and r= 0.67 (95% CI 0.08-0.69) respectively. The median differences in TSS between OS with PFS, OS with PFS-2, and PFS2 with PFS were 8.7, 8.4, and 3.2 months respectively. For trials with a SPP < 12 months, smaller differences in the median TSS as compared to SPP ≥12 months were seen. The median differences in follow-up required to reach statistical significance were 329, 151 and 122 person-years (PY) respectively. These differences were equivalent to a median 18.3% increase in sample size required for PFS-2 over PFS. The median increase in sample sizes were 18.2% and 22.3% for trials with SPP < 12 and ≥12 months respectively. Conclusions: PFS-2 has a stronger correlation with OS benefit than PFS. When PFS-2 is used as primary endpoint, trials will require an additional median 3.2 months to achieve statistical significance, and an additional 18.3% increase of sample size over PFS. PFS-2 balances between improved correlation with OS but modest increase in follow-up time and sample size. PFS-2 should therefore be considered as a primary endpoint in future trials of advanced cancers.[Table: see text]

DREAM3R: Durvalumab with chemotherapy as first-line treatment in advanced pleural mesothelioma—A phase 3 randomized trial

TPS8599

Background: Combination PD1/CTLA4 immune checkpoint blockade and platinum-pemetrexed (CP) chemotherapy are standard first-line options for the treatment of unresectable malignant pleural mesothelioma (MPM). Two recent, single-arm, phase 2 trials (DREAM and PrE0505) combining the PD-L1 inhibitor durvalumab and standard first line CP both exceeded pre-specified efficacy criteria. The Phase 3 DREAM3R trial aims to determine the effectiveness of including durvalumab with first line CP chemotherapy in advanced MPM. Methods: Treatment-naïve patients with advanced MPM will be randomized (2:1) to either durvalumab 1500 mg every 3 weeks plus chemotherapy (cisplatin 75 mg/m2 or carboplatin AUC 5 and pemetrexed 500 mg/m2) every 3 weeks for 4-6 cycles (Arm A), followed by durvalumab 1500 mg every 4 weeks until disease progression, unacceptable toxicity or patient withdrawal, versus doublet chemotherapy alone for 4-6 cycles with all patients monitored for progression. The target sample size is 480 patients recruited over 27 months, with follow up for an additional 24 months. This provides over 85% power if the true hazard ratio for overall survival (OS) is 0.70, with 2-sided alpha of 0.05, assuming a median OS of 15 months in the control group. Key eligibility criteria include: MPM of any histological subtype; measurable disease per RECIST 1.1 modified for mesothelioma (mRECIST 1.1); ECOG PS 0-1; and adequate hematologic, renal, and liver function. Exclusions: Prior systemic anticancer treatment for MPM, diagnosis based solely on cytology or fine needle aspiration biopsy, contraindication to immunotherapy or conditions requiring immunosuppressive agents or corticosteroids. Patients will be further stratified at randomization by: Age (18-70 years vs. > 70), sex, histology (epithelioid vs. non-epithelioid), planned platinum (cisplatin vs. carboplatin) and geographic region (USA vs. ANZ). The primary endpoint is OS. Secondary endpoints include progression-free survival; objective tumor response; adverse events; health-related quality of life; and healthcare resource use in ANZ. Tertiary correlative objectives aim to further explore and validate potential prognostic and/or predictive biomarkers (including those identified in the DREAM and PrE0505 studies, PD-L1 expression, tumor mutation burden, genomic characteristics, and HLA subtypes) via tissue and serial blood samples. An imaging databank will be assembled for validation of radiological measures of response, and studies of possible radiomic biomarkers in mesothelioma. The study is active and enrolling in both ANZ and in the US. Clinical trial information: NCT04334759 and ACTRN 12620001199909.

Pre- and on-treatment lactate dehydrogenase as a prognostic and predictive biomarker in advanced non-small cell lung cancer

BACKGROUND

The survival outcomes of patients with advanced non–small cell lung cancer (NSCLC) treated with immune checkpoint inhibitors (ICIs) are variable. This study investigated whether pre‐ and on‐treatment lactate dehydrogenase (LDH) could better prognosticate and select patients for ICI therapy.

METHODS

Using data from the POPLAR and OAK trials of atezolizumab versus docetaxel in previously treated advanced NSCLC, the authors assessed the prognostic and predictive value of pretreatment LDH (less than or equal to vs greater than the upper limit of normal). They further examined changes in on‐treatment LDH by performing landmark analyses and estimated overall survival (OS) distributions according to the LDH level stratified by the response category (complete response [CR]/partial response [PR] vs stable disease [SD]). They repeated pretreatment analyses in subgroups defined by the programmed death ligand 1 (PD‐L1) status.

RESULTS

This study included 1327 patients with available pretreatment LDH. Elevated pretreatment LDH was associated with an adverse prognosis regardless of treatment (hazard ratio [HR] for atezolizumab OS, 1.49; P = .0001; HR for docetaxel OS, 1.30; P = .004; P for treatment by LDH interaction = .28). Findings for elevated pretreatment LDH were similar for patients with positive PD‐L1 expression treated with atezolizumab. Persistently elevated on‐treatment LDH was associated with a 1.3‐ to 2.8‐fold increased risk of death at weeks 6, 12, 18, and 24 regardless of treatment. Elevated LDH at 6 weeks was associated with significantly shorter OS regardless of radiological response (HR for CR/PR, 2.10; P = .04; HR for SD, 1.50; P < .01), with similar findings observed at 12 weeks.

CONCLUSIONS

In previously treated advanced NSCLC, elevated pretreatment LDH is an independent adverse prognostic marker. There is no evidence that pretreatment LDH predicts ICI benefit. Persistently elevated on‐treatment LDH is associated with worse OS despite radiologic response.

This analysis of 1327 patients with advanced non–small cell lung cancer from the POPLAR and OAK randomized controlled trials has found that lactate dehydrogenase (LDH) is a useful pre‐ and on‐treatment prognostic marker that can assist clinicians in counselling patients undergoing second‐ or later‐line atezolizumab or docetaxel. However, the findings fail to support the use of LDH as a predictive biomarker for immune checkpoint inhibitor therapy and reinforce the importance of rigorous validation of promising predictive biomarkers using randomized data.

The validity of progression-free survival 2 as a surrogate trial end point for overall survival

BACKGROUND

Overall survival (OS) is the gold-standard end point for oncology trials. However, the availability of multiple therapeutic options after progression and crossover to receive investigational agents confound and delay OS data maturation. Progression-free survival 2 (PFS-2), defined as the time from randomization to progression on first subsequent therapy, has been proposed as a surrogate for OS. Using a meta-analytic approach, the authors aimed to assess the association between OS and PFS-2 and compare this with progression-free survival 1 (PFS-1) and the objective response rate (ORR).

METHODS

An electronic literature search was performed to identify randomized trials of systemic therapies in advanced solid tumors that reported PFS-2 as a prespecified end point. Correlations between OS and PFS-2, OS and PFS-1, and OS and ORR as hazard ratios (HRs) or odds ratios (ORs) were assessed via linear regression weighted by trial size.

RESULTS

Thirty-eight trials were included, and they comprised 19,031 patients across 8 tumor types. PFS-2 displayed a moderate correlation with OS (r = 0.67; 95% confidence interval [CI], 0.08-0.69). Conversely, correlations of ORR (r = 0.12; 95% CI, 0.00-0.13) and PFS-1 (r = 0.21; 95% CI, 0.00-0.33) were poor. The findings for PFS-2 were consistent for subgroup analyses by treatment type (immunotherapy vs nonimmunotherapy: r = 0.67 vs 0.67), survival post progression (<12 vs ≥12 months: r = 0.86 vs 0.79), and percentage not receiving subsequent treatment (<50% vs ≥50%: r = 0.70 vs 0.63).

CONCLUSIONS

Across diverse tumors and therapies, the treatment effect on PFS-2 correlated moderately with the treatment effect on OS. PFS-2 performed consistently better than PFS-1 and ORR, regardless of postprogression treatment and postprogression survival. PFS-2 should be included as a key trial end point in future randomized trials of solid tumors.

Incorporating circulating tumor DNA detection to radiographic assessment for treatment response in advanced EGFR-mutant lung cancer

PURPOSE

Response Evaluation Criteria in Solid Tumors (RECIST) has limitations but remains the conventional approach for tumor assessments. We explored whether circulating tumor DNA (ctDNA) can be incorporated into RECIST to provide a more robust measure of tumor response in advanced EGFR-mutant NSCLC.

PATIENTS AND METHODS

In FASTACT-2, patients with advanced NSCLC received platinum/gemcitabine intercalated with erlotinib or placebo. EGFR mutation (tumor and plasma ctDNA) was detected using cobas v2. Patients selected for this hypothesis-generating analysis had EGFR mutations (on either tumor or plasma) at baseline and evaluable week 8 plasma EGFR. Week 8 ctDNA and radiologic response status were correlated with survival using landmark cox regression analyses.

RESULTS

Of the original 451 patients, 86 (19.1%) were eligible for this analysis. 73% (n = 63) had detectable ctDNA at baseline. At week 8, 40% (n = 34) had radiologic partial response (PR), 60% (n = 52) had stable disease (SD); 80% (n = 69) had a ctDNA response (undetectable ctDNA). In patients who had initial PR and undetectable ctDNA, 93% (28/30) had ongoing PR subsequently at week 16. The median duration of response was 14.9 months. In patients with SD and undetectable ctDNA at week 8, 28% had radiological PR at week 16. Amongst those with PR at week 8, survival outcomes for those with undetectable vs detectable ctDNA were not statistically significant (PFS HR 0.49, 95%CI 0.16-1.48, p = 0.21; OS HR 0.39, 95%CI 0.13-1.19, p = 0.10). Amongst those with SD at week 8, there was significantly longer survival for those with undetectable vs detectable ctDNA (PFS HR 0.27, 95% CI 0.13-0.57, p < 0.0001; OS HR 0.40, 95% CI 0.20-0.80, p = 0.009).

CONCLUSION

In patients with SD, undetectable ctDNA at week 8 correlated with survival improvement. Both radiologic and ctDNA responses are prognostic of PFS. Incorporation of ctDNA with RECIST may improve tumor response assessment in EGFR-mutant NSCLC.

Tumor Response End Points as Surrogates for Overall Survival in Immune Checkpoint Inhibitor Trials: A Systematic Review and Meta-Analysis

PURPOSE

Many immune checkpoint inhibitors (ICIs) have been approved on the basis of tumor response end points in nonrandomized trials, including objective response rate (ORR) and duration and depth of response. We aimed to assess the validity of these end points as surrogate end points for overall survival (OS) in patients with advanced solid tumors treated with ICIs at trial and treatment arm levels.

METHODS

ICI trials in advanced solid cancers published between January 1, 2000, and March 31, 2020, were included. Correlations between ORR, durable response (DR) of ≥ 6 months, complete response (CR), and OS were assessed for treatment comparisons (trial-level) and for patients receiving ICI (arm-level), using weighted linear regression.

RESULTS

Sixty-three trials were eligible, including 58 randomized controlled trials and 20 nonrandomized controlled trials (78 ICI arms and 30,815 patients). The majority were phase III (63%), and OS was the most common primary end point (40%). In relative treatment comparisons, correlations between ORR risk ratio and OS hazard ratio (HR), 6-month DR ratio and OS HR, and CR ratio and OS HR were r = 0.58, r = 0.62, and r = 0.42, respectively. Exploratory studies in melanoma, non-small-cell lung cancer, and other tumors showed similar results, although 6-month DR ratio was strongly correlated with OS HR (r = 0.89). Within ICI arms only, correlations between ORR and 12-month OS, 6-month DR and 12-month OS, and CR and 12-month OS were r = 0.76, r = 0.84, and r = 0.50, respectively, in all eligible trials.

CONCLUSION

Relative measures of tumor response (ORR, 6-month DR, and CR) are poor surrogate end points for OS in ICI studies. However, ORR and 6-month DR are prognostic of 12-month OS in ICI studies supporting their use for screening activity of novel agents in early-phase nonrandomized trials.

Clinical activity of durvalumab for patients with advanced mismatch repair-deficient and repair-proficient endometrial cancer. A nonrandomized phase 2 clinical trial

BACKGROUND

In this study, we assessed the activity of durvalumab, an antibody to programmed death ligand-1, in two cohorts of women with advanced endometrial cancers (AEC)-mismatch repair proficient (pMMR) and mismatch repair deficient (dMMR).

METHODS

A multicenter phase two study was performed in women with AEC with pMMR tumor progressing after one to three lines of chemotherapy and women with AEC with dMMR tumor progressing after zero to three lines of chemotherapy. Mismatch repair status was based on immunohistochemistry expression. All women received durvalumab 1500 mg given every 4 weeks until progression or unacceptable toxicity. The primary endpoint was objective tumor response by RECIST V.1.1 modified for immune-based therapeutics.

RESULTS

Seventy-one women were recruited: 35 dMMR and 36 pMMR. Median follow-up was 19 vs 21 months in dMMR versus pMMR, respectively. Median age was 67 years. Histology in dMMR versus pMMR included endometrioid (94% vs 57%) and serous (0% vs 31%) and was high grade in 26% vs 74%. The objective tumor response rate (OTRR) in the dMMR cohort was 47% (17/36, 95% CI 32 to 63), including 6 complete responses and 11 partial responses (PRs)) vs 3% in the pMMR cohort (1/35, 95% CI 1 to 15, PR). In the dMMR cohort, durvalumab was the first-line therapy in 58% (OTRR 57%) and the second-line therapy in 39% (OTRR 38%). Median progression-free survival was 8.3 months in the dMMR cohort vs 1.8 months in the pMMR cohort. The 12-month overall survival (OS) rate was 71% in dMMR vs 51% in pMMR, with median OS not reached for dMMR vs 12 months for pMMR. Immune-related adverse events occurred in 14 women, mostly grades 1-2.

CONCLUSION

Durvalumab monotherapy showed promising activity and acceptable safety in AEC with dMMR regardless of prior lines of chemotherapy, but activity was limited in AEC with pMMR.

TRIAL REGISTRATION NUMBERS

ANZGOG1601, ACTRN12617000106336, and NCT03015129.

DREAM3R: Durvalumab with chemotherapy as first-line treatment in advanced pleural mesothelioma—A phase 3 randomized trial

TPS8586

Background: Standard first line treatment for unresectable malignant pleural mesothelioma (MPM) is platinum-based chemotherapy with pemetrexed. Two recent, single-arm, phase 2 trials (DREAM1 and PrE05052) combining the PD-L1 inhibitor durvalumab and standard first line cisplatin and pemetrexed (CP) exceeded pre-specified criteria for proceeding to phase 3. DREAM3R aims to determine the effectiveness of adding durvalumab to first line CP chemotherapy in advanced MPM. Methods: Treatment-naïve patients with advanced MPM will be randomised (2:1) to EITHER durvalumab 1500 mg every 3 weeks plus doublet chemotherapy (cisplatin 75 mg/m2 and pemetrexed 500 mg/m2) every 3 weeks for 4-6 cycles, followed by durvalumab 1500 mg every 4 weeks until disease progression, unacceptable toxicity or patient withdrawal; OR doublet chemotherapy alone for 4-6 cycles, followed by observation. The target sample size is 480 patients (320 durvalumab, 160 control) recruited over 27 months, with follow up for an additional 24 months. This provides over 85% power if the true hazard ratio for overall survival is 0.70, with 2-sided alpha of 0.05, assuming a median survival of 15 months in the control group. Key inclusion criteria: MPM of any histological subtype; measurable disease as per RECIST 1.1 modified for mesothelioma (mRECIST 1.1) without prior radiotherapy to these sites; ECOG PS 0-1; and, adequate hematologic, renal, and liver function tests. Key exclusion criteria: prior systemic anticancer treatment for MPM; diagnosis based only on cytology or fine needle aspiration biopsy; contraindication to immunotherapy; and conditions requiring immunosuppressives or corticosteroids. Stratification: Age (18-70 years vs. > 70), sex, histology (epithelioid vs. non-epithelioid), and region (USA vs. ANZ). The primary endpoint is overall survival. Secondary endpoints include progression-free survival; objective tumour response (by mRECIST 1.1 and iRECIST); adverse events; health-related quality of life; and healthcare resource use. Tertiary correlative objectives are to explore and validate potential prognostic and/or predictive biomarkers (including features identified in the DREAM and PrE0505 studies, PD-L1 expression, tumour mutation burden, nuanced genomic characteristics, and HLA subtypes) in tissue and serial blood samples. An imaging databank will be assembled for validation of radiological measures of response, and studies of possible radiomic biomarkers in mesothelioma. Clinical trial information: NCT04334759. and ACTRN 12620001199909.

Tumor-associated immune cells and progression-free survival in advanced endometrial cancer (EC), results from the PHAEDRA trial (ANZGOG 1601)

5584

Background: Activity of durvalumab in patients with deficient mismatch repair (dMMR) advanced endometrial carcinoma (EC) was confirmed in the PHAEDRA trial (ANZGOG 1601). This study investigated the association between immune biomarkers and clinical outcomes in PHAEDRA. Methods: Formalin-fixed paraffin embedded sections immunohistochemically stained for PD-L1 using the Ventana platform, were with matched H&E slides scored independently by two pathologists according to the Ventana PD-L1 (SP263) algorithm for urothelial carcinoma (UC). Immune biomarkers assessed were PD-L1 staining of tumor cells (TCP) and immune cells (IC), and presence of tumor-associated immune cells (ICP). Results: Sixty-seven of the 71 patients had sufficient tumor for PD-L1 testing. AUC were 0.667, 0.726 and 0.644 for TCP, ICP and IC, respectively for predicting tumor response. Optimal cutpoints were TCP≥1%, ICP≥10% and IC≥35%. ICP≥10% achieved the highest sensitivity (53%) and specificity (82%) of the individual cutpoints. The optimal cutpoint algorithm was able to identify patients who would not respond, (sensitivity 88%, negative predictive value 92%), but had low specificity (48%) and positive predictive value (37%). Differences in PFS were found using ICP≥10% (logrank p = 0.01), compared to TCP (p = 0.25), IC (p = 0.48) and the UC algorithm (p = 0.08) (Figure 1). PFS was shorter in patients with pMMR than dMMR after adjusting for ICP (HR 2.99, 95%CI: 1.61-5.57, p < 0.001). Adjustment for MMR reduced the prognostic significance of ICP≥10% for PFS (HR 0.59, 95% CI: 0.28-1.23, p = 0.16). For OS, differences were seen for the UC algorithm (p = 0.02), but not ICP (p = 0.07), TCP (p = 0.18) or IC (p = 0.23). Similarly to PFS, adjustment for MMR reduced the prognostic significance of the UC algorithm for OS (HR: 0.53, 95% CI: 0.25-1.12, p = 0.10). Conclusions: In this exploratory analysis, ICP was more closely associated with tumor response and PFS than TCP or IC. ICP alone was better than the UC algorithm for predicting PFS. The optimum cutpoint algorithm was promising for identifying non-responders, but requires external validation. Clinical trial information: ACTRN12617000106336.

The validity of progression-free survival (PFS) 2 as a surrogate endpoint for overall survival (OS) in randomized controlled trials (RCTs) of advanced solid tumors

1516

Background: OS is the gold-standard endpoint for treatment efficacy in oncology RCTs. However, prolonged follow-up is required to obtain mature data, which impedes regulatory approval of potentially beneficial therapies. Furthermore, increasing therapeutic options including cross over to investigational agents at disease progression often confound OS findings. PFS-2, defined as time from randomization to progression on second-line therapy, has been proposed as a potential surrogate endpoint for OS. Using a meta-analytic approach, we aimed to assess the association between OS and PFS-2, and its validity compared with other surrogate endpoints. Methods: We performed an electronic literature search to identify RCTs of systemic therapies that reported PFS-2 as a pre-specified endpoint with defined follow up protocols. Articles were screened for eligibility and outcome data were extracted. Correlations in the relative treatment difference between treatment arms for OS vs PFS-2, PFS-1, and objective response rate (ORR) were assessed as the comparison of hazard ratios (HR) and odds ratio (OR) respectively. Results: 38 eligible RCTs comprising of 44 analysis units, with 19,031 patients across 8 unique tumor types were identified. The majority received targeted therapies (72.2%), followed by immunotherapy (IO; 26.3%). The correlations of HR-OS/HR-PFS-2, HR-OS/HR-PFS-1 and HR-OS/OR-ORR were r = 0.67 (95% CI 0.08-0.69), r = 0.12 (95% CI 0.00-0.13) and r = 0.21 (95% CI 0.00-0.33) respectively. Correlations between OS with surrogates was assessed in different subgroups according to post-progression survival times (SPP), types of treatment agents and rate of subsequent therapy after progression (table). Conclusions: Across diverse tumors and therapies, treatment effect on PFS-2 has modest to strong correlation with OS, but poor correlations were observed between OS-PFS-1 and OS-ORR respectively. Across all subgroups, PFS-2 performs consistently better than traditional surrogates of PFS-1 and ORR, validating and providing support for use in future RCTs.[Table: see text]

Clinical utility of plasma EGFR mutation detection with quantitative PCR in advanced lung cancer: A meta-analysis

OBJECTIVES

To assess the clinical utility of quantitative PCR (qPCR) assays, a routinely used test for detection of epidermal growth factor receptor (EGFR) mutation in circulating tumour DNA (ctDNA) in treatment-naive advanced lung cancer patients.

MATERIALS AND METHODS

We performed a meta-analysis of randomized controlled trials (RCTs) with individual patient data. Eligible RCTs compared EGFR-tyrosine kinase inhibitor (EGFR-TKI) and chemotherapy in first line setting for advanced lung cancer, and included tumour EGFR+ (tEGFR+) with paired ctDNA results using real-time (quantitative) PCR. We assessed the proportion of tEGFR + detected by ctDNA, and compared the effectiveness of EGFR-TKI versus chemotherapy in ctDNA + and ctDNA- subgroups.

RESULTS

Six randomized clinical trials included 1058 tEGFR + patients with paired baseline EGFR ctDNA testing. Of these, 460 (43 %) tested ctDNA- (ctDNA+ 57 %). Progression-free survival was longer for EGFR-TKI versus chemotherapy for both ctDNA+ (HR 0.28; 95 % CI 0.22-0.36, p < 0.00001) and ctDNA- subgroups (HR 0.37; 95 % CI 0.28-0.49, p < 0.00001; p-interaction = 0.14). Objective response rate (odds ratio 6.21; 95 % CI 4.25-9.07, p < 0.00001 vs 6.44; 95 % CI 4.21-9.87, p < 0.00001) and overall survival (HR 0.82; 95 % CI 0.70-1.04 vs HR 0.77; 95CI% 0.59-1.00) similarly favoured EGFR-TKI in both ctDNA + and ctDNA- subgroups respectively.

CONCLUSION

Our findings indicate that approximately two in five tissue EGFR mutation-positive patients will not be detected using a qPCR assay, but would still potentially benefit from highly effective EGFR-TKI treatment. A negative EGFR ctDNA result via qPCR testing is therefore insufficient to exclude benefit from EGFR-TKI. Attempts should be made to repeat EGFR testing with a tissue biopsy in this patient group. As newer ctDNA assays with better sensitivity become available, the clinical impact for any false negatives will remain an important consideration.

Durvalumab with first-line chemotherapy in previously untreated malignant pleural mesothelioma (DREAM): a multicentre, single-arm, phase 2 trial with a safety run-in

BACKGROUND

There is a strong unmet need to improve systemic therapy in mesothelioma. Chemotherapy with cisplatin and pemetrexed improves survival in malignant pleural mesothelioma, and immune checkpoint inhibitors are an emerging treatment in this disease. We aimed to evaluate the activity of durvalumab, an anti-PD-L1 antibody, given during and after first-line chemotherapy with cisplatin and pemetrexed in patients with advanced malignant pleural mesothelioma.

METHODS

DREAM was a multicentre, single-arm, open-label, phase 2 trial done in nine hospitals in Australia. Eligible patients were aged 18 years or older and had histologically confirmed malignant pleural mesothelioma considered unsuitable for cancer-directed surgery, an Eastern Cooperative Oncology Group performance status of 0 or 1, and measurable disease as per the modified Response Evaluation Criteria in Solid Tumors version 1.0 (mRECIST) for mesothelioma that was previously untreated with systemic therapy. All histological subtypes were eligible. The first six participants were treated for two cycles in a safety run-in. All participants received cisplatin 75 mg/m², pemetrexed 500 mg/m², and durvalumab 1125 mg intravenously on day 1 of a 3-weekly schedule for a maximum of six cycles. Change from cisplatin to carboplatin with an area under the curve of 5 was permitted. Durvalumab was continued for a maximum of 12 months. The primary endpoint was progression-free survival at 6 months, measured according to mRECIST for malignant pleural mesothelioma and analysed in the intention-to-treat population. Safety analyses included all participants who receive at least one dose of any study drug. This study is registered with the Australia New Zealand Clinical Trials Registry, ACTRN12616001170415.

FINDINGS

Between Dec 28, 2016, and Sept 27, 2017, 55 participants were enrolled. 54 patients were eligible and were followed up for a median of 28·2 months (IQR 26·5-30·2). 31 (57%; 95% CI 44-70) of 54 patients were alive and progression-free at 6 months. The most common grade 3-4 adverse events were neutropenia (seven [13%] patients), nausea (six [11%]), and anaemia (four [7%]). A total of 60 serious adverse events occurred in 29 participants, five of which were considered possibly related to durvalumab. Five patients died during the study treatment; none of these five deaths were attributed to study treatment.

INTERPRETATION

The combination of durvalumab, cisplatin, and pemetrexed has promising activity and an acceptable safety profile that warrants further investigation in a randomised phase 3 trial.

FUNDING

AstraZeneca.

Validation of Progression-Free Survival Rate at 6 Months and Objective Response for Estimating Overall Survival in Immune Checkpoint Inhibitor Trials: A Systematic Review and Meta-analysis

IMPORTANCE

Progression-free survival (PFS) rate at 6 months has been proposed as a potential surrogate for overall survival (OS) rate at 12 months for immune checkpoint inhibitor (ICI) trials but requires further assessment for validation.

OBJECTIVE

To validate 6-month PFS and objective response rate (ORR) as estimators of 12-month OS in the ICI arms of randomized clinical trials (RCTs).

DATA SOURCES

Electronic databases (Medline, EMBASE, and the Cochrane Central Register of Controlled Trials) were searched for ICI RCTs published between January 2000 and June 2019.

STUDY SELECTION

Eligible studies were phase 2 and phase 3 ICI RCTs in advanced solid cancers that reported ORR, PFS, and OS. A total of 99 articles (from 60 studies) of 2502 articles were selected by consensus.

DATA EXTRACTION AND SYNTHESIS

Data were screened and extracted independently. Estimation models for 12-month OS and to assess correlation coefficient between end points were developed using linear regression. Data were extracted in July 2019, and analyses were conducted in September 2019. This study is reported following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline.

MAIN OUTCOMES AND MEASURES

Validation of previously reported 6-month PFS and ORR estimation models for 12-month OS using contemporary RCTs. Calibration of 6-month PFS and ORR model-estimated vs observed 12-month OS in ICI arms were assessed by correlation coefficient (r) and weighted Brier scores. Secondary analyses were performed for subgroups (ie, ICI-only, ICI-combination, line of therapy, programmed cell death 1 ligand 1 selected, and unselected).

RESULTS

Data from 60 RCTs with 74 experimental ICI arms were used. The development data set included 25 arms from studies published January 2000 to January 2017. The estimation model for 12-month OS using 6-month PFS was: (1.06 × PFS6) + 0.16 + (0.04 × melanoma) - (0.03 × NSCLC) + (0 × other tumors), in which PFS6 indicates 6-month PFS and NSCLC indicates non-small cell lung cancer. The estimation model for 12-month OS using ORR was (0.15 × ORR) + 0.52 + (0 × melanoma) - (0.02 × NSCLC) - (0.01 × other tumors). A total of 49 arms from studies published after January 2017 to June 2019 formed the validation data set. When the models were applied on the validation data set, calibration between the 6-month PFS model estimated vs observed 12-month OS was good (r = 0.89; Brier score, 0.008), but poor for the ORR model (r = 0.47; Brier score, 0.03). Findings were similar across all subgroups.

CONCLUSIONS AND RELEVANCE

The findings of this study suggest that the estimation model using 6-month PFS could reliably estimate 12-month OS in ICI trials. This study could assist in better selection and prioritization of ICI agents for testing in RCTs based on phase 2 single-arm RCT results.

A systematic evaluation of compliance and reporting of patient-reported outcome endpoints in ovarian cancer randomised controlled trials: implications for generalisability and clinical practice

Background

This study aimed to evaluate the patient-reported outcome (PRO) content of ovarian cancer randomised-controlled trial (RCT) publications, describe PRO compliance, and explore potential relationships among these and completeness of PRO protocol content.

Methods

Publications of Phase III ovarian cancer RCTs with PRO endpoints were identified by Medline and Cochrane systematic search: January 2000 to February 2016. Two reviewers determined the number of Consolidated Standards of Reporting Trials (CONSORT)-PRO Extension items addressed in publications. Compliance rates (defined as the proportion of participants included in the principal PRO analysis, of those from whom PRO assessments were expected) were extracted. The relationship between CONSORT-PRO score and compliance rates was explored using scatter plots. Additionally CONSORT-PRO score and PRO compliance rates respectively were compared with corresponding PRO protocol scores obtained from a previous study.

Results

Thirty-six eligible RCTs (n = 33 with secondary PRO endpoint) were identified and analysed. The average number of CONSORT-PRO items addressed in publications was 6.7 (48%; Range 0–13.5/14). Three RCTs did not report PRO results; in 1 case due to poor compliance. Some compliance information was reported in 26 RCTs, but was considered complete for only 10 (28%) RCTs. Compliance rates were poor overall, ranging from 59 to 83%; therefore missing PRO data from 17 to 41% of participants in these trials could have been avoided.

Of the 26 (73%) RCTs for which PRO protocol completeness scores were available, 6 RCTs reported complete compliance information and the 3 of these RCTs with highest PRO compliance had highest protocol checklist scores.

Conclusions

Few RCTs reported PRO compliance information in a manner enabling assessment of the generalisability of PRO results. This information is particularly important in RCTs of advanced ovarian cancer because it is important to be able to determine if missing data was due to worsening illness compared to methodological issues. Poor compliance appeared related to poor PRO protocol content, and in one case prevented PRO results from being reported, highlighting the need to address compliance strategies in the protocol. Adhering to protocol and CONSORT-PRO reporting guidance should improve PRO implementation and reporting respectively in ovarian cancer RCTs and allow results to meaningfully inform clinical practice.

Electronic supplementary material

The online version of this article (doi:10.1186/s41687-017-0008-3) contains supplementary material, which is available to authorized users.

The patient-reported outcome content of international ovarian cancer randomised controlled trial protocols

PURPOSE

Patient-reported outcomes (PROs) provide the patient's perspective of the impact of treatment. Evidence suggests that PRO content of randomised controlled trials (RCTs) protocols is generally sub-optimal. This study aimed to describe and evaluate the PRO-specific content of ovarian cancer RCT protocols.

METHODS

Published, phase III, ovarian cancer RCTs with PRO endpoints were identified following a systematic search of Medline and Cochrane databases (Jan 2000 to Feb 2016). Corresponding RCT protocols were downloaded (if published) or obtained by contacting authors. Two investigators independently assessed adherence of PRO-specific content of included protocols to a checklist of 58 recommended PRO protocol items currently being developed by the International Society for Quality of Life Research. Discrepancies were resolved with a third investigator.

RESULTS

Of 41 eligible trials identified, 26 protocols were assessed (developed 1995-2010). We were unable to obtain the remaining 15 protocols. Protocols addressed a mean of 28 % PRO checklist items (range 8-66 %). Fifteen (58 % of assessed protocols) provided a rationale for PRO assessment, 8 (31 %) described a PRO objective, 24 (92 %) included a PRO assessment schedule, but only 6 (23 %) justified timing of PRO assessments. Twelve protocols (46 %) provided staff data collection instructions, 4 (15 %) included plans for monitoring PRO compliance, and 16 (62 %) included a PRO analysis plan.

CONCLUSIONS

On average, protocols addressed less than one-third of PRO protocol checklist items. In some cases, key guidance regarding PRO administration was lacking, which may lead to inconsistent and sub-optimal PRO methodology. Efforts are needed to improve PRO protocol content in cancer trials.