Dancey, Janet

PURPOSE The mode of action of targeted cancer agents (TCAs) differs from classic chemotherapy, which leads to concerns about the role of RECIST in evaluating tumor response in trials with TCAs. We investigated the performance of RECIST using a pooled database from 50 clinical trials with at least one TCA. METHODS We examined the impact of the number of target lesions (TLs) on within-patient variability of tumor response. The prognostic effect of TL response (at 12 weeks or on study on the basis of a maximum five TLs) on survival was studied through landmark and time-dependent Cox models adjusted for baseline tumor load, occurrence of new lesions, or unequivocal progression of nontarget disease. RESULTS Data were obtained from 23,259 patients with cancer (36% lung, 28% colorectal, 11% breast, and 25% other); 15,620 received TCAs, predominantly transduction or angiogenesis inhibitors, as a single agent (37%), combined with other TCAs (7%), or as chemotherapy (56%); 28% received chemotherapy only; and 5% received best supportive care or placebo. A total of 17,222 patients contributed to the analyses. Within-patient variability decreased with increasing number of TLs, similarly for TCAs (with/without chemotherapy) and chemotherapy only. Mixed responses occurred proportionally in all treatment classes. Landmark analyses showed an ordinal relationship between percentage change from baseline to 12 weeks and overall survival, and demonstrated a clear distinction between tumor shrinkage and progressive disease according to RECIST. Time-dependent analysis showed no marked improvement in the ability to predict survival on the basis of TL tumor growth compared with nontarget progression or new lesion occurrence, regardless of treatment. Similar results were seen for major tumor types and different classes of TCAs. CONCLUSION This work reinforces that RECIST version 1.1 perform well for response assessment of TCAs.

2534 Background: The Response Evaluation Criteria in Solid Tumors (RECIST) v1.1 were derived from an international collaborative effort supported by data from clinical trials (16 studies, 9147 patients) on cytotoxic chemotherapy (CT), providing a standard tool for response assessment. RECIST’s role has been questioned for TCA. Using a pooled individual patient database (IPD) from clinical trials performed by industry and cooperative groups, we assessed whether modifications to RECIST are required to evaluate antitumor activity of TCA. Methods: Data were collected from phase 2 and 3 clinical trials testing TCA in solid tumors. To study the occurrence of mixed responses, the variability of response of lesions within patients was studied. Furthermore, response was correlated with survival through landmark analyses and time dependent Cox models. Results: Clinical data were obtained from 23,259 patients, mainly with lung (36%), colorectal (28%) or breast cancer (11%). 15,620 patients (67%) received a TCA, mainly transduction or angiogenesis inhibitors, either as single agent (37%) or combined with other TCAs (7%) or CT (56%); 28% received CT only and 5% best supportive care or placebo. Within-patient variability reduced as the number of lesions used for response assessment increased, and did so similarly for TCAs (+/- CT) and CT. Mixed responses seemed to occur similarly across these treatment categories as well. Landmark analyses showed improving overall survival by % tumor shrinkage and a clear distinction between the effect of tumor shrinkage and progressive disease (PD) according to RECIST 1.1. This was confirmed by time dependent analysis. In addition target lesion growth showed no marked improvement in overall survival prediction over and above the other components of RECIST 1.1 PD (new lesions, non-target PD), regardless of treatment (TCA, CT or both) received. Similar results were seen focusing on major tumor types and classes of TCA. Conclusions: Using a large IPD dataset we demonstrated that RECIST 1.1 performs equally well for response assessment of TCA as for CT. No modifications are required.

BACKGROUNDMitogen‐activated protein kinase (MAPK) activation and mammalian target of rapamycin (mTOR)‐dependent signaling are hallmarks of glioblastoma. In the current study, the authors conducted a phase 1/2 study of sorafenib (an inhibitor of Raf kinase and vascular endothelial growth factor receptor 2 [VEGFR‐2]) and the mTOR inhibitor temsirolimus in patients with recurrent glioblastoma.METHODSPatients with recurrent glioblastoma who developed disease progression after surgery or radiotherapy plus temozolomide and with ≤2 prior chemotherapy regimens were eligible. The phase 1 endpoint was the maximum tolerated dose (MTD), using a cohorts‐of‐3 design. The 2‐stage phase 2 study included separate arms for VEGF inhibitor (VEGFi)–naive patients and patients who progressed after prior VEGFi.RESULTSThe MTD was sorafenib at a dose of 200 mg twice daily and temsirolimus at a dose of 20 mg weekly. In the first 41 evaluable patients who were treated at the phase 2 dose, there were 7 who were free of disease progression at 6 months (progression‐free survival at 6 months [PFS6]) in the VEGFi‐naive group (17.1%); this finding met the prestudy threshold of success. In the prior VEGFi group, only 4 of the first 41 evaluable patients treated at the phase 2 dose achieved PFS6 (9.8%), and this did not meet the prestudy threshold for success. The median PFS for the 2 groups was 2.6 months and 1.9 months, respectively. The median overall survival for the 2 groups was 6.3 months and 3.9 months, respectively. At least 1 adverse event of grade ≥3 was observed in 75.5% of the VEGFi‐naive patients and in 73.9% of the prior VEGFi patients.CONCLUSIONSThe limited activity of sorafenib and temsirolimus at the dose and schedule used in the current study was observed with considerable toxicity of grade ≥3. Significant dose reductions that were required in this treatment combination compared with tolerated single‐agent doses may have contributed to the lack of efficacy. Cancer 2018;124:1455‐63. © 2018 American Cancer Society.

Background Temsirolimus (CCI-779) is a small-molecule inhibitor of the mammalian target of rapamycin (mTOR) and represents a rational therapeutic target against glioblastoma multiforme (GBM). Methods Recurrent GBM patients with ≤ 1 chemotherapy regimen for progressive disease were eligible. Temsirolimus was administered in a 250-mg intravenous dose weekly. Results Sixty-five patients were treated. The incidence of grade 3 or higher nonhematologic toxicity was 51%, and consisted mostly of hypercholesterolemia (11%), hypertriglyceridemia (8%), and hyperglycemia (8%). Grade 3 hematologic toxicity was observed in 11% of patients. Temsirolimus peak concentration (Cmax), and sirolimus Cmax and area under the concentration-time curve were decreased in patients receiving p450 enzyme–inducing anticonvulsants (EIACs) by 73%, 47%, and 50%, respectively, but were still within the therapeutic range of preclinical models. Twenty patients (36%) had evidence of improvement in neuroimaging, consisting of decrease in T2 signal abnormality +/− decrease in T1 gadolinium enhancement, on stable or reduced steroid doses. Progression-free survival at 6 months was 7.8% and median overall survival was 4.4 months. Median time to progression (TTP) for all patients was 2.3 months and was significantly longer for responders (5.4 months) versus nonresponders (1.9 months). Development of grade 2 or higher hyperlipidemia in the first two treatment cycles was associated with a higher percentage of radiographic response (71% v 31%; P = .04). Significant correlation was observed between radiographic improvement and high levels of phosphorylated p70s6 kinase in baseline tumor samples (P = .04). Conclusion Temsirolimus is well tolerated in recurrent GBM patients. Despite the effect of EIACs on temsirolimus metabolism, therapeutic levels were achieved. Radiographic improvement was observed in 36% of temsirolimus–treated patients, and was associated with significantly longer TTP. High levels of phosphorylated p70s6 kinase in baseline tumor samples appear to predict a patient population more likely to derive benefit from treatment. These findings should be validated in other studies of mTOR inhibitors.