Chee Khoon Lee

Informative censoring in maintenance therapy trials for advanced ovarian cancer: An empirical assessment of its impact on treatment benefit

A considerable proportion of patients in ovarian cancer maintenance trials may be censored in progression-free survival (PFS) analyses, the primary study endpoint. Such censoring is often informative, reflecting discontinuation due to toxicity, preference, or early switch to alternative therapies, potentially biasing results toward overestimating PFS benefit. We aimed to quantify the impact of informative censoring on PFS in these trials. Double-blind, placebo-controlled maintenance therapy trials were selected, and individual patient data reconstructed from published survival curves. A sensitivity analysis reclassified varying proportions of all censored events as progressions to model scenarios from 0 % to 100 % informative censoring. Hazard ratios (HRs) were re-estimated and compared with the originally reported values. Duration of therapy was compared with PFS. Twenty-two trial units (N = 8256) were included. Nineteen reported statistically significant results, falling to 14 (74 %) at the upper limit of analysis. HRs diminished progressively, with a 6 % reduction at 10 % censoring and 29 % at 100 %. In nine PARP inhibitor trials, treatment duration was shorter than PFS (mean of medians = 12.5 vs 17.6 months). Results were consistent when limited to PARP inhibitor studies. No correlation was observed between adverse events and censoring. Informative censoring can substantially distort PFS benefit estimates in ovarian cancer maintenance trials. Transparent reporting of censoring rates and their causes is essential for meaningful clinical interpretation and should be standard in all randomised maintenance therapy trials.

Poor Concordance Between Cancer Antigen-125 and RECIST Assessment for Progression in Patients With Platinum-Sensitive Relapsed Ovarian Cancer on Maintenance Therapy With a Poly(ADP-ribose) Polymerase Inhibitor

PURPOSE Cancer antigen-125 (CA-125) is recommended by treatment guidelines and widely used to diagnose ovarian cancer recurrence. The value of CA-125 as a surrogate for disease progression (PD) and its concordance with radiologic progression are unclear, particularly for women with platinum-sensitive relapsed ovarian cancer (PSROC) who have responded to chemotherapy and treated with maintenance poly(ADP-ribose) polymerase inhibitor (PARPi). METHODS In this pooled analysis of four randomized trials of maintenance PARPi or placebo (Study 19, SOLO2, ARIEL3, and NOVA), we extracted data on CA-125 PD as defined by Gynecologic Cancer InterGroup criteria and RECIST v1.1. We evaluated the concordance between CA-125 and RECIST PD and reported on the negative predictive value (NPV) and positive predictive value (PPV). RESULTS Of 1,262 participants (n = 818 PARPi, n = 444 placebo), 403 (32%) had CA-125 PD, and of these, 366 had concordant RECIST PD (PPV, 91% [95% CI, 88 to 93]). However, of 859 (68%) without CA-125 PD, 382 also did not have RECIST PD (NPV, 44% [95% CI, 41 to 48]). Within the treatment arms, PPV remained high (PARPi, 91% [95% CI, 86 to 94]; placebo, 91% [95% CI, 86 to 95]) but NPV was lower on placebo (PARPi, 53% [95% CI, 49 to 57]; placebo, 25% [95% CI, 20 to 31]). Of 477 with RECIST-only PD, most (95%) had a normal CA-125 at the start of maintenance therapy and the majority (n = 304, 64%) had CA-125 that remained within normal range. Solid organ recurrence without peritoneal disease was more common in those with RECIST-only PD than in those with CA-125 and RECIST PD (36% v 24%; P < .001). CONCLUSION In patients with PSROC treated with maintenance PARPi, almost half with RECIST PD did not have CA-125 PD, challenging current guidelines. Periodic computed tomography imaging should be considered as part of surveillance, particularly in those with a normal CA-125 at the start of maintenance therapy and on treatment.

Impact of chemotherapy on patients with mismatch repair deficient advanced endometrial carcinomas—a meta-analysis

Abstract Background Chemo-immunotherapy is standard of care for women with recurrent or advanced mismatch repair deficient endometrial carcinoma. However, it is uncertain whether patients with mismatch repair deficient advanced or recurrent endometrial carcinoma derive less benefit from chemotherapy than those with mismatch repair proficient endometrial carcinoma. Methods We performed a meta-analysis of randomized controlled trials (RCTs) in advanced or recurrent endometrial carcinoma to determine the difference in the benefit of chemotherapy in mismatch repair deficient vs mismatch repair proficient endometrial carcinoma. Data on chemotherapy outcomes including objective response rate, progression-free survival (PFS), and overall survival were retrieved. We pooled these data using the inverse variance method and examined subgroup difference by mismatch repair status. We also compared differences in PFS and overall survival outcomes by creating individual patient data from the Kaplan–Meier curves of trial publications for sensitivity analyses. Results A total of 5 RCTs with 1137 participants (mismatch repair deficient, 26%; mismatch repair proficient, 74%) were included. All participants were treated with carboplatin-based chemotherapy. There was no difference between the mismatch repair deficient and mismatch repair proficient subgroups for objective response rate (66.5% vs 64.0%; P = .20 for subgroup difference), PFS (hazard ratio [HR] = 0.93, 95% confidence interval [CI] = 0.77 to 1.12; P = .44; median PFS = 7.6 vs 9.5 months) or overall survival (HR = 1.03, 95% CI = 0.73 to 1.44; P = .88; median overall survival = not reached vs 28.6 months). Conclusions Objective response rate, PFS, and overall survival were similar among those with mismatch repair deficient vs mismatch repair proficient endometrial cancer treated with front-line, platinum-doublet chemotherapy in RCTs. These findings reinforce the importance of combining chemotherapy together with immune checkpoint inhibitors until the results of trials comparing immune checkpoint therapy alone with combination therapy are available.

Prognostic nomogram for progression-free survival in patients with BRCA mutations and platinum-sensitive recurrent ovarian cancer on maintenance olaparib therapy following response to chemotherapy

The impact of maintenance therapy with PARP inhibitors (PARPi) on progression-free survival (PFS) in patients with BRCA mutations and platinum-sensitive recurrent ovarian cancer (PSROC) varies widely. Individual prognostic factors do not reliably distinguish patients who progress early from those who have durable benefit. We developed and validated a prognostic nomogram to predict PFS in these patients. The nomogram was developed using data from a training patient cohort with BRCA mutations and high-grade serous PSROC on the placebo arm of two maintenance therapy trials, Study 19 and SOLO2/ENGOT-ov21. We performed multivariable Cox regression analysis based on pre-treatment characteristics to develop a nomogram that predicts PFS. We assessed the discrimination and validation of the nomogram in independent validation patient cohorts treated with maintenance olaparib. The nomogram includes four PFS predictors: CA-125 at randomisation, platinum-free interval, presence of measurable disease and number of prior lines of platinum therapy. In the training (placebo) cohort (internal validation C-index 0.64), median PFS in the model-predicted good, intermediate and poor-risk groups was: 7.7 (95% CI 5.3-11.3), 5.4 (4.8-5.8) and 2.9 (2.8-4.4) months, respectively. In the validation (olaparib) cohort (C-index 0.71), median PFS in the model-predicted good, intermediate and poor-risk groups was: not reached, 16.6 (13.1-22.4) and 8.3 (7.1-10.8) months, respectively. The nomogram showed good calibration in the validation cohort (calibration plot). This nomogram can be used to predict PFS and counsel patients with BRCA mutations and PSROC prior to maintenance olaparib and for stratification of patients in trials of maintenance therapies.

Reporting the trajectories of adverse events over the entire treatment course in patients with recurrent platinum-sensitive ovarian cancer treated with platinum-based combination chemotherapy regimens: A graphical approach to trial adverse event reporting

Clinical trials report adverse events (AEs) in a dense table focusing on the frequency of 'worst grade' AEs experienced over the duration of treatment. There is usually no granular information provided on the timing and trajectory of AEs or whether they are likely to worsen, improve, or remain constant over time. Non-hematologic (NH) AE data was extracted from the CALYPSO trial comparing carboplatin with pegylated liposomal doxorubicin (CD) to carboplatin with paclitaxel (CP) in recurrent ovarian cancer (ROC). Generalised estimating equations (GEE) were used to assess the risk and trajectory of combined Grade 2 or higher (G2+) AE and of each specific AE. The risk of G2+AE was also compared between treatment arms. The study included 976 patients and AE were reported for the duration of treatment. Most patients experienced at least one G2+NHAE (CP:CD, 96.0%:80.6%). Risk of combined G2+AE increased with CP (4.1% per-cycle) but decreased with CD (0.8%, P <0.01). When alopecia and sensory neuropathy were excluded, risk of G2+ AE decreased by 2.7% per-cycle, with no significant difference between treatment arms. G2+ nausea improved (15.2% per-cycle, P <0.01). G2+ sensory neuropathy worsened (29.3% per-cycle, P <0.01). Fatigue was stable (17% per-cycle, P =0.06) whilst G2+ pain decreased over time (13.4% per-cycle, P <0.01), with no difference between treatment arms. Existing trial data can be used to provide AE trajectories as illustrated here for ROC. These trajectories have utility in guiding treatment choice and potentially optimising AE management with novel therapies and treatment combinations.

Molecular and clinical predictors of improvement in progression‐free survival with maintenance PARP inhibitor therapy in women with platinum‐sensitive, recurrent ovarian cancer: A meta‐analysis

BACKGROUNDThe authors performed a meta‐analysis to better quantify the benefit of maintenance poly(ADP‐ribose) polymerase inhibitor (PARPi) therapy to inform practice in platinum‐sensitive, recurrent, high‐grade ovarian cancer for patient subsets with the following characteristics: germline BRCA mutation (gBRCAm), somatic BRCA mutation (sBRCAm), wild‐type BRCA but homologous recombinant‐deficient (HRD), homologous recombinant‐proficient (HRP), and baseline clinical prognostic characteristics.METHODSRandomized trials comparing a PARPi versus placebo as maintenance treatment were identified from electronic databases. Treatment estimates of progression‐free survival were pooled across trials using the inverse variance weighted method.RESULTSFour trials included 972 patients who received a PARPi (olaparib, 31%; niraparib, 35%; or rucaparib, 34%) and 530 patients who received placebo. For patients who had germline BRCA1 mutation (gBRCAm1) (N = 471), the hazard ratio (HR) was 0.29 (95% CI, 0.23‐0.37); for those who had germline BRCA2 mutation (gBRCAm2) (N = 236), the HR was 0.26 (95% CI, 0.17‐0.39); and, for those who had sBRCAm (N = 123), the HR was 0.22 (95% CI, 0.12‐0.41). The treatment effect was similar between the gBRCAm and sBRCAm subsets (P = .48). In patients who had wild‐type BRCA HRD tumors (excluding sBRCAm; N = 309), the HR was 0.41 (95% CI, 0.31‐0.56); and, in those who had wild‐type BRCA HRP tumors (N = 346), the HR was 0.64 (95% CI, 0.49‐0.83). The relative treatment effect was greater for the BRCAm versus HRD (P = .03), BRCAm versus HRP (P &lt; .00001), and HRD versus HRP (P &lt; .00001) subsets. There was no difference in benefit based on age, response after recent chemotherapy, and prior bevacizumab.CONCLUSIONSIn platinum‐sensitive, recurrent, high‐grade ovarian cancer, maintenance PARPi improves progression‐free survival for all patient subsets. PARPi therapy has a similar magnitude of benefit for sBRCAm and gBRCAm. Although patients with BRCAm derive the greatest benefit, the absence of a BRCAm or HRD could not be used to exclude patients from maintenance PARPi therapy.

Adverse events in the placebo arm of maintenance therapy trials in advanced ovarian cancer: A systematic review and meta-analysis

Maintenance treatment is standard of care for front-line (FL) and platinum-sensitive recurrent ovarian cancer (PSROC) following response to chemotherapy. Adverse events (AEs) on maintenance therapies are common and usually attributable to investigational treatments but could also be unrelated. Randomised controlled trial (RCT) with blinded placebo design is the gold standard for determining the relative differences in efficacy and AEs between treatment arms. We performed a meta-analysis to quantify AE rates in placebo arms of RCTs to determine AEs not due to investigational agents. We performed an electronic search to identify eligible RCTs in FL and PSROC settings. Data from placebo arms were extracted and pooled using the inverse variance method to determine the risk of any AE, overall and specific grade 3 or higher (G ≥ 3) AEs, and AE-related treatment delay, reduction and discontinuation. We identified 13 eligible RCTs (FL, N = 8; PSROC, N = 5) with 2224 patients who received placebo (FL, N = 1541; PSROC, N = 683). The majority experienced an AE of any grade (FL, 93.0%; PSROC, 95.2%). Substantial proportions experienced G ≥ 3 AEs (FL, 14.6%; PSROC, 18.2%). In the FL setting, AEs led to treatment delay in 14.4%, dose reduction in 4.1% and discontinuation in 2.6%. Findings were similar for PSROC: 8.4%, 5.5% and 2.1%, respectively. AEs not due to investigational agents are common in ovarian cancer patients in maintenance therapy RCTs. Potential explanations include the nocebo effect, residual toxicities from previous treatment or underlying disease. Further research is required to identify better approaches to assessing AEs in this population.

Olaparib, durvalumab, and cyclophosphamide, and a prognostic blood signature in platinum-sensitive ovarian cancer: the randomized phase 2 SOLACE2 trial

Abstract SOLACE2 (ACTRN12618000686202) investigates whether 12-weeks of olaparib, or cyclophosphamide-olaparib priming, improves subsequent durvalumab-olaparib progression-free survival (PFS), and is superior to olaparib monotherapy without any priming, in platinum-sensitive recurrent ovarian cancer (n = 114). We also evaluate the utility of CUP-CC assay, an immune signature of C-C chemokine receptor type 4 up-regulation, chemokines, and cytokines. Priming with olaparib, or cyclophosphamide-olaparib, followed by durvalumab-olaparib, are both associated with longer PFS compared to olaparib monotherapy, but do not reach the pre-specified primary endpoint of 36-week trial threshold (PFS36). PFS36 rates are 47.4% (95% CI, 31.0-62.1; olaparib priming then olaparib-durvalumab), 48.7% (32.5-63.2; olaparib-cyclophosphamide then olaparib-durvalumab) and 35.1% (20.4-50.3; olaparib monotherapy). PFS is significantly longer for the homologous recombination deficient (N = 71) as compared to the proficient (HRP) (N = 29) subgroups (Hazard Ratio (HR) 0.55, 0.35-0.87). CUP-CC+ subgroup (N = 58) has a significantly longer PFS (HR 0.31, 0.19-0.49) than CUP-CC- (N = 46). Future studies should investigate whether CUP-CC has the potential to personalize poly (ADP-ribose) polymerase inhibitor therapies for patients who are BRCA wild-type, including HRP patients.