Iris Kuss

Efficacy and safety of regorafenib for advanced gastrointestinal stromal tumours after failure of imatinib and sunitinib (GRID): an international, multicentre, randomised, placebo-controlled, phase 3 trial.

BACKGROUND Until now, only imatinib and sunitinib have proven clinical benefit in patients with gastrointestinal stromal tumours (GIST), but almost all metastatic GIST eventually develop resistance to these agents, resulting in fatal disease progression. We aimed to assess efficacy and safety of regorafenib in patients with metastatic or unresectable GIST progressing after failure of at least imatinib and sunitinib. METHODS We did this phase 3 trial at 57 hospitals in 17 countries. Patients with histologically confirmed, metastatic or unresectable GIST, with failure of at least previous imatinib and sunitinib were randomised in a 2:1 ratio (by computer-generated randomisation list and interactive voice response system; preallocated block design (block size 12); stratified by treatment line and geographical region) to receive either oral regorafenib 160 mg daily or placebo, plus best supportive care in both groups, for the first 3 weeks of each 4 week cycle. The study sponsor, participants, and investigators were masked to treatment assignment. The primary endpoint was progression-free survival (PFS). At disease progression, patients assigned placebo could crossover to open-label regorafenib. Analyses were by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT01271712. RESULTS From Jan 4, to Aug 18, 2011, 240 patients were screened and 199 were randomised to receive regorafenib (n=133) or matching placebo (n=66). Data cutoff was Jan 26, 2012. Median PFS per independent blinded central review was 4·8 months (IQR 1·4-9·2) for regorafenib and 0·9 months (0·9-1·8) for placebo (hazard ratio [HR] 0·27, 95% CI 0·19-0·39; p<0·0001). After progression, 56 patients (85%) assigned placebo crossed over to regorafenib. Drug-related adverse events were reported in 130 (98%) patients assigned regorafenib and 45 (68%) patients assigned placebo. The most common regorafenib-related adverse events of grade 3 or higher were hypertension (31 of 132, 23%), hand-foot skin reaction (26 of 132, 20%), and diarrhoea (seven of 132, 5%). INTERPRETATION The results of this study show that oral regorafenib can provide a significant improvement in progression-free survival compared with placebo in patients with metastatic GIST after progression on standard treatments. As far as we are aware, this is the first clinical trial to show benefit from a kinase inhibitor in this highly refractory population of patients. FUNDING Bayer HealthCare Pharmaceuticals.

Randomized phase II study of lonaprisan as second-line therapy for progesterone receptor-positive breast cancer

BACKGROUND The progesterone-receptor (PR) antagonists onapristone (type I) and mifepristone (type II) showed modest activity in hormone-receptor-positive breast cancer; however, onapristone in particular was associated with hepatotoxicity. Lonaprisan is a novel, type III PR antagonist that was well tolerated in phase I studies. PATIENTS AND METHODS This randomized, open-label, phase II study evaluated the efficacy and tolerability of lonaprisan as second-line endocrine therapy in postmenopausal women with stage IV, PR-positive, HER2-negative, metastatic breast cancer. RESULTS Patients received once-daily lonaprisan 25 mg (n = 34) or 100 mg (n = 34). The primary objective was not met (≥ 35% clinical benefit rate: complete/partial responses at any time until month 6 or stable disease [SD] for ≥ 6 months from start of treatment). There were no complete/partial responses. In the 25 mg and 100 mg groups, 6 of 29 patients (21%) and 2 of 29 patients (7%), respectively, had SD ≥ 6 months. Overall, 61 of 68 patients (90%) had ≥ 1 adverse event (AE), the most frequent (≥ 10% overall) being fatigue, hot flush, dyspnoea, nausea, asthenia, headache, constipation, vomiting, and decreased appetite; 33 patients had serious AEs. CONCLUSION Lonaprisan showed limited efficacy as second-line endocrine therapy in postmenopausal women with PR-positive metastatic breast cancer.

Randomized phase III trial of regorafenib in patients (pts) with metastatic and/or unresectable gastrointestinal stromal tumor (GIST) progressing despite prior treatment with at least imatinib (IM) and sunitinib (SU): GRID trial.

LBA10008 Background: Oral multikinase inhibitor regorafenib (REG) demonstrated substantial activity in a phase II trial in pts with GIST after failure of both IM and SU (J Clin Oncol. 2011; 29:606s; abstr 10007). This phase III, randomized, double-blind, placebo-controlled trial evaluated the efficacy and safety of REG for this unmet clinical need. METHODS Eligible pts had metastatic and/or unresectable GIST, objective failure of both prior IM and SU (progressive disease [PD] on, or intolerance to, IM and PD on SU), ≥1 measurable lesion, ECOG performance status 0 or 1. Pts were randomized 2:1 to receive best supportive care plus either REG 160 mg po once daily (3 wks on/1 wk off) or placebo (PL). The primary endpoint was progression-free survival (PFS) (modified RECIST 1.1, independent central review). Secondary endpoints included overall survival (OS), disease control rate (DCR, defined as rate of partial response [PR] plus stable disease [SD] lasting for ≥12 wks), response rate and duration, safety and correlative genotype analyses. At time of PD, pts were eligible for unblinding and crossover to open-label REG. RESULTS Between Jan and Aug of 2011, 234 pts were screened; 199 were randomized (REG: 133, PL: 66). Pts were stratified at randomization according to number of prior systemic therapies and geographical region. Baseline characteristics were balanced between the two arms. The primary endpoint was met: median PFS was 4.8 months for REG vs. 0.9 months for PL. Hazard ratio for PFS was 0.27 (95% CI, 0.18-0.39), p<0.0001. PFS rates at 3 and 6 months were 60% and 38% for REG vs. 11% and 0% for PL. DCR was 53% (REG) vs. 9% (PL).The HR for OS was 0.77 (p=0.20) with 85% PL pts having crossed over to REG. The most common > grade 3 treatment-emergent AEs in the REG arm during double-blind study were hypertension (28%), hand-foot skin reaction (21%), and diarrhea (8%). CONCLUSIONS This randomized trial demonstrated that REG significantly improved PFS and DCR in pts with advanced GIST after failure of at least prior IM and SU. REG was well tolerated, with AEs as expected for this class and manageable with dose modifications.

Abstract LB-295: Detection of oncogenic kinase mutations in circulating plasma DNA and correlation with clinical benefit in the phase III GRID study of regorafenib vs placebo in TKI-refractory metastatic GIST.

Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC Background: GRID is a phase III study for patients with advanced gastrointestinal stromal tumors (GIST) following failure of imatinib (I) and sunitinib (S) who were randomized to receive either the multikinase inhibitor regorafenib (R) or placebo (P). R demonstrated a highly significant improvement in progression-free survival compared with P (HR 0.27, p<0.0001). A preplanned retrospective biomarker analysis was conducted to assess GIST genotypes in GRID patients and to explore the possible impact of different driver oncogene mutations on clinical outcomes. Methods: DNA was isolated from archival tumor tissue and analyzed for KIT mutations via Sanger sequencing. The expectation was that primary KIT mutations would be detectable in archival tissue but that secondary KIT mutations may be undetectable in tissues obtained before treatment with I or S. To overcome this potential limitation, plasma samples drawn at GRID study entry, post I and S failure, were used as a source of circulating DNA for evaluation of GIST oncogenic mutations (KIT, PDGFRA, BRAF) via BEAMing technology. Results: KIT mutations were detected in 83 of 138 (60%) plasma samples and 64 of 99 (65%) tumor tissue samples analyzed. Primary KIT exon 11 and 9 mutations were identified in approximately 42% and 18% of the tissue samples, respectively. The frequency of the canonical exon 9 mutations was similar for plasma and tissue samples, showing consistency between mutation-detection technologies. With limitations of tumor-based assays, a lower incidence of secondary KIT resistance mutations was detected in patient-matched archival tumor tissue compared with plasma samples: resistance mutations were detected in 12% of tissue samples vs 48% of plasma samples. Most (76%) secondary KIT mutations detected in plasma DNA were located in the KIT activation loop encoding structural alterations known to mediate resistance to I and S. Nearly half of the plasma samples in which secondary KIT mutations were identified harbored multiple secondary mutations, consistent with the results of previous studies on fresh tumor biopsies taken following resistance to both I and S. R was clinically active compared with P in all KIT mutational subgroups evaluated (HR 0.27 in patients with KIT exon 9 mutations; HR 0.25 in patients with secondary KIT mutations identified via plasma DNA). Conclusions: In GIST patients from the GRID trial, driver oncogenic mutations and secondary oncogenic mutations leading to I and S resistance are readily detectable via BEAMing of circulating DNA from plasma. BEAMing may provide a real-time assessment of tumor genotype in GIST and other cancers using blood-derived circulating DNA, that may be more comprehensive than tumor sampling. GIST patients with a wide spectrum of primary and secondary mutations in oncogenic kinases benefit from treatment with R. Citation Format: George D. Demetri, Michael Jeffers, Peter Reichardt, Yoon-Koo Kang, Jean-Yves Blay, Piotr Rutkowski, Hans Gelderblom, Peter Hohenberger, Michael Leahy, Margaret von Mehren, Heikki Joensuu, Giuseppe Badalamenti, Martin Blackstein, Axel Le Cesne, Patrick Schoffski, Robert G Maki, Sebastian Bauer, Binh Bui Nguyen, Jianming Xu, Toshirou Nishida, John Chung, Chetan D. Lathia, Christian Kappeler, Iris Kuss, Dirk Laurent, Paolo G Casali. Detection of oncogenic kinase mutations in circulating plasma DNA and correlation with clinical benefit in the phase III GRID study of regorafenib vs placebo in TKI-refractory metastatic GIST. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-295. doi:10.1158/1538-7445.AM2013-LB-295

611TiPADJUVANT REGORAFENIB (REG) IN STAGE IV COLORECTAL CANCER (CRC) AFTER CURATIVE TREATMENT OF LIVER METASTASES: A PHASE III RANDOMIZED, PLACEBO (PBO)-CONTROLLED TRIAL (COAST)

ABSTRACT Background: Complete resection and pre-/peri-/post-operative chemotherapy are the standard of care for patients with stage IV CRC and resectable metastases confined to the liver. Despite this treatment approach, long-term disease-free survival of patients with resected liver metastases is poor. The oral multikinase inhibitor REG significantly improved overall survival (OS) in patients with metastatic CRC that had progressed after all standard therapies (CORRECT study; HR 0.77; one-sided p = 0.0052; Lancet 2013). COAST will evaluate the efficacy and safety of REG vs PBO in patients with CRC after curative resection of liver metastases and completion of planned chemotherapy. Trial design: This double-blind, PBO-controlled, multicenter, phase III study (ClinicalTrials.gov identifier NCT01939223) will randomize patients (n = 750 planned) 1 : 1 to treatment with oral REG 160 mg or PBO once daily in 4-week cycles of 3 weeks on, 1 week off treatment. Doses of study drug may be delayed or reduced to manage clinically significant drug-related toxicities. Treatment will continue for 2 years or until recurrence of CRC, death, intolerable toxicity, or patient/investigator decision to stop. Inclusion criteria include age ≥18 years, stage IV CRC, pathology-proven complete resection of liver metastases, and ECOG performance status 0 or 1. Patients must have completed adjuvant, neoadjuvant, or perioperative chemotherapy. Randomization will be stratified by number of preoperative liver metastases ( 6 months), and time since last surgery for any CRC lesion (≤6 months vs >6 months). The primary endpoint is disease-free survival (DFS), assessed by the investigator using computed tomography or magnetic resonance imaging. Secondary endpoints include OS, health-related quality of life, and biomarker evaluations. Analyses will be performed when approximately 317 DFS events are observed, at which time the study will have 90% power to detect a 50% improvement in median DFS. The first patient entered the study in February 2014 and the estimated primary completion date is March 2018.Previously presented at WCGI 2014 abstract number: 749 (to be presented at WCGI 2014 as a poster presentation). Disclosure: A. Grothey: has the following financial disclosures: Advisory board: Bayer Corporate sponsored research: Bayer, Genentech, Eisai, Pfizer, ImClone, Daiichi; T. Yoshino: has the following financial disclosures: Corporate sponsored research: Daiichi Sankyo, Taiho, Bayer, Eli Lilly, Pfizer, Chugai, and Yakult; J. Zalcberg: has the following financial disclosures: Advisory board: Bayer, Roche Research and travel support, expert testimony: Bayer, Roche; D.J. Sargent: has the following financial disclosures: Advisory board: Bayer, Roche Corporate sponsored research: Roche, Celgene; M. Choti: has the following financial disclosures: Research consultant: Bristol Myers Squibb; M. Rutstein: has the following financial disclosures: Employment: Bayer HealthCare; L. Cupit: has the following financial disclosures: Employment: Bayer; I. Kuss: has the following financial disclosures: Employment: Bayer Pharma AG; E. Van Cutsem: has the following financial disclosures: Corporate sponsored research: Bayer . All other authors have declared no conflicts of interest.

Abstract 929: Tumor genotyping in the phase III GRID study of regorafenib vs placebo in tyrosine kinase inhibitor (TKI)-refractory GIST: Detection of KIT mutations in circulating tumor DNA comparing digital PCR and massive parallel sequencing

Background: The GRID study demonstrated that regorafenib provides a significant improvement in progression-free survival (HR 0.27; p Methods: 91 plasma samples from patients enrolled in the Ph 3 study (GRID) for which BEAMing data (Jeffers et al 2013 JCO 31:10503) were subjected to Safe-SeqS covering cKit Exon 8 to Exon 18. Results: In 6 of 32 samples reported to be cKIT wildtype by BEAMing, mutations were identified by SafeSeqS. The detection of primary KIT exon 9 mutations showed a high degree of concordance among the two mutation-detection methods evaluated. Secondary / resistance hotspot mutations were also readily detected by both methods, although a greater number of such mutations were detected by Safe-SeqS than by BEAMing. The localization of the additional mutations detected by Safe-SeqS in known mutational hotspots supports their legitimacy. Safe-SeqS also detected KIT mutations for which BEAMing assays had not been developed, whereas in 17 samples a mutation for which a BEAMing assay was available was not detectable by Safe SeqS. In 58% (10/17) of samples, the mutant allele frequency found by BEAMing was close to the detection limit of this platform ( Conclusion: Our data support the use of Safe-SeqS as a sensitive and specific “liquid biopsy” method for non-invasive tumor genotyping of patients with GIST, enabling the identification of known and novel tumor-associated mutations using circulating DNA. These results confirm and extend the genotypic heterogeneity that had previously been identified in GRID circulating DNA samples by BEAMing. The comprehensive tumor mutational profiles generated by Safe-SeqS will be used to evaluate potential correlations between tumor genotype and clinical outcome. Citation Format: Michael Jeffers, Henrik Seidel, Susanne Schwenke, Joachim Reischl, Mark Rutstein, Christian Kappeler, Iris Kuss, Michael Teufel. Tumor genotyping in the phase III GRID study of regorafenib vs placebo in tyrosine kinase inhibitor (TKI)-refractory GIST: Detection of KIT mutations in circulating tumor DNA comparing digital PCR and massive parallel sequencing. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 929. doi:10.1158/1538-7445.AM2015-929