Touat, Mehdi

2006 Background: Adaptive randomization adjusts enrollment rates based upon early trial results, which can allow for decreased enrollment for therapies less likely to meet the primary endpoint of a trial. CC-115, a CNS-penetrant, oral inhibitor of mammalian target of rapamycin kinase (mTOR) and deoxyribonucleic acid-dependent protein kinase (DNA-PK), was evaluated in the Individualized Screening Trial of Innovative Glioblastoma Therapy (INSIGhT) trial. As CC-115 was discontinued due to concerns about toxicity and unfavorable risk-to-benefit ratio, we sought to investigate the impact of adaptive randomization in its testing. Methods: In INSIGhT, adults with newly diagnosed MGMT-unmethylated glioblastoma and available genomic data are adaptively randomized to an experimental arm or the control arm of standard radiotherapy with concurrent and adjuvant temozolomide. Patients randomized to CC-115 received it (10mg po BID) with radiotherapy and as adjuvant monotherapy, and a safety lead-in 3+3 design was used for this arm. By simulating the INSIGhT trial with standard uniform randomization, we estimated the reduction of enrollment rate and sample size of the CC-115 arm that was attributable to adaptive randomization. Results: Twelve patients were randomized to CC-115; 58% (n = 7) patients had possible treatment-related CTCAE grade > 3 toxicity. Compared to the control arm, there was no significant difference in progression-free survival (PFS, HR 0.66, 95% CI 0.32-1.36, p = 0.3) or overall survival (OS, HR 0.93, 95% CI 0.43-2.03, p = 0.8). Based on early PFS results, randomization probability to CC-115 decreased from 25% to 16%. At the time of the CC-115 arm closure, 14% of enrolled INSIGhT patients had been randomized to this arm. Compared to average expected enrollment by standard randomization, the use of adaptive randomization decreased the number of patients randomized to CC-115 by 50% (12 patients vs. 18 patients [95% CI 11-25 patients]). Conclusions: The INSIGhT trial, designed with adaptive randomization, facilitated more efficient testing of CC-115 and decreased the number of patients allocated to the CC-115 arm relative to a standard randomization design. Clinical trial information: NCT02977780.

Abstract BACKGROUND CC-115 is an oral, CNS-penetrant, selective inhibitor of mammalian target of rapamycin kinase (mTOR) and deoxyribonucleic acid-dependent protein kinase (DNA-PK). Both targets are important in glioblastoma; PI3K/Akt/mTOR signaling is hyperactive in most glioblastomas, and DNA-PK is integral to repair of radiotherapy-mediated DNA damage. To investigate CC-115 in newly diagnosed glioblastoma and explore potential genomic biomarker associations, CC-115 was evaluated in the Individualized Screening Trial of Innovative Glioblastoma Therapy (INSIGhT) trial, an adaptive platform trial designed to efficiently test experimental agents. METHODS Adults with newly diagnosed MGMT-unmethylated glioblastoma, with genomic data available, are eligible for this ongoing trial. Patients are adaptively randomized to one of several experimental arms or the control arm: standard radiotherapy with concurrent and adjuvant temozolomide. The primary endpoint is overall survival (OS). Patients randomized to CC-115 (10mg po BID) received it concurrently with radiotherapy and as adjuvant monotherapy. As the first in-human use of CC-115 with radiation, a safety lead-in 3 + 3 design was used. RESULTS Twelve patients were randomized to CC-115; seven patients had possible treatment-related CTCAE grade > 3 toxicity, including four pre-specified dose-limiting toxicities: liver function abnormality (n=1), hyperlipidemia (n=1), lipase elevation (n=1) and cerebral edema (n=1). There was no significant difference in progression-free survival (PFS, median 4.2 months [CC-115] vs. 5.2 months, p=0.9) or OS (median 10.1 months [CC-115] vs. 14.5 months, p=0.9) compared to the 50 patients randomized to the control arm. Based on early PFS results, randomization probability to CC-115 decreased from 25% to < 10% at time of the trial arm closure. CONCLUSION Concurrent and adjuvant CC-115 was associated with toxicity and failed to improve PFS or OS. The INSIGhT trial design allowed for more efficient testing of CC-115, decreasing patients and resources allocated to a therapy that was discontinued due to concerns about toxicity and unfavorable risk-to-benefit ratio.

Abstract BACKGROUND The cyclin D-CDK4/6-Rb pathway is activated in most glioblastomas. Abemaciclib is a potent CDK4/6 inhibitor with good brain penetration approved for ER/PR/HER2- breast cancer. In order to efficiently evaluate the potential impact of abemaciclib on overall survival (OS) in newly diagnosed glioblastoma and to simultaneously develop information regarding potential genomic biomarker associations, abemaciclib was included as an arm on the Individualized Screening Trial of Innovative Glioblastoma Therapy (INSIGhT) trial. INSIGhT is a phase II platform trial using response adaptive randomization and deep genomic profiling to more efficiently test experimental agents in MGMT unmethylated glioblastoma and potentially accelerate identification of novel therapies for phase III testing. Initial randomization was equal between abemaciclib, control, and two other experimental arms but subsequent randomization was adapted based on efficacy as determined by progression-free survival (PFS). Ineffective arms were discontinued and new arms added by protocol amendment. We report preliminary results for the abemaciclib arm which has completed accrual. METHODS Patients with newly diagnosed MGMT-unmethylated glioblastoma were randomized to receive either radiotherapy with concomitant and adjuvant temozolomide at standard doses or standard radiochemotherapy followed by adjuvant abemaciclib (150–200 mg orally BID) without temozolomide. Treatment continued until progression or development of unacceptable toxicities. The primary endpoint was OS. Association between abemaciclib efficacy and cyclin D-CDK4/6-Rb pathway genomic alterations was also investigated. RESULTS There were 123 patients (50 control; 73 treated with abemaciclib). Abemaciclib was generally well-tolerated with no new toxicity signals identified. PFS was significantly longer (p=0.03, logrank test) with abemaciclib (median 6.31 months 95% CI [5.29, 8.18]) compared to the control arm (5.16 months 95% CI [4.37, 6.28]). 28/50 control and 36/73 abemaciclib patients remain alive. CONCLUSION Preliminary analysis suggests that abemaciclib increases PFS compared to control. Updated toxicity, PFS and survival data and potential genomic biomarker associations will be presented.