Dataset Information

ACTR-68. CONCORDANCE OF EGFR AND MGMT ANALYSES BETWEEN LOCAL AND CENTRAL LABORATORIES: IMPLICATIONS FOR CLINICAL TRIAL DESIGN AND PRECISION MEDICINE FOR DEPATUXIZUMAB-MAFODOTIN (ABT-414) IN GLIOBLASTOMA (GBM)

ABSTRACT: Abstract BACKGROUND Depatuxizumab-mafodotin is an EGFR-directed monoclonal antibody that targets activated EGFR (wild type or EGFRvIII) conjugated to a microtubule inhibitor. EGFRamp correlated with recurrent GBM response in a phase I trial (M12-356, NCT01800695), thus becoming a centrally determined inclusion criterion in an ensuing phase II/III randomized study for newly diagnosed disease now accruing (RTOG 3508, M13-813, NCT02573324). Centrally detected EGFRvIII mutation and MGMT promoter methylation are also stratification factors in RTOG 3508 to balance randomization for biomarkers of potential predictive or prognostic significance. Allowing use of locally determined molecular profiling may reduce accrual barriers by avoiding added time of tissue shipping and repeat central testing. However, discordant results between local and central tests could confound interpretation of clinical trial results. Therefore, we compared local vs. central biomarker results among patients screened for M12-356 or RTOG 3508 at Columbia University Medical Center (CUMC). METHODS We retrospectively tabulated local and central EGFRamp, EGFRvIII, and MGMT results. EGFRamp was analyzed by FISH/CISH and EGFRvIII and MGMT by PCR, although the assays for each differed slightly between laboratories. RESULTS 109 GBMs were molecularly profiled from 73 patients who underwent 1–4 resection(s) and screened for M12-356 (n=44) or RTOG 3508 (n=29) at CUMC. EGFRamp, EGFRvIII, and MGMT promoter methylation each was observed in 54, 36, and 27% of tumors tested locally vs. 68, 33, and 43% centrally, respectively. Concordance between laboratories was observed 88%, 86%, and 61%. CONCLUSIONS EGFRamp and EGFRvIII results were mainly concordant (over 85%) between local and central laboratories. EGFRamp frequency was higher centrally, likely biased by investigators who preferentially sent cases known to harbor EGFRamp locally for central testing. Of concern, MGMT results were discordant in 39%. Allowing local MGMT testing for stratification could unacceptably imbalance randomization if confirmed in a larger dataset.

SUBMITTER: Lassman A

PROVIDER: S-EPMC5692946 | biostudies-literature | 2017 Nov

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:BACKGROUND:Epidermal growth factor receptor (EGFR) alterations are associated with multiple cancers. Current EGFR-directed therapies have led to increased efficacy but are associated with specific side effects. The antibody-drug conjugate depatuxizumab mafodotin (depatux-m) targets EGFR with a monoclonal antibody linked to a cytotoxin, and is highly tumor-specific. METHODS:This phase 1/2 study evaluated the safety, pharmacokinetics, and efficacy of depatux-m in patients who had advanced solid tumors with known wild-type EGFR overexpression, amplification, or mutated EGFR variant III. A 3 + 3 dose escalation was used, and 2 dosing schedules were evaluated. Depatux-m also was manufactured under an alternate process to reduce the drug load and improve the safety profile, and it was tested at the maximum tolerated dose (MTD). In another cohort, prolonged infusion time of depatux-m was evaluated; and a cohort with confirmed EGFR amplification also was evaluated at the MTD. RESULTS:Fifty-six patients were treated. The MTD and the recommended phase 2 dose for depatux-m was 3.0 mg/kg. Common adverse events (AEs) were blurred vision (48%) and fatigue (41%). A majority of patients (66%) experienced 1 or more ocular AEs. Grade 3 or 4 AEs were observed in 43% of patients. One patient with EGFR-amplified, triple-negative breast cancer had a partial response. Stable disease was observed in 23% of patients. Pharmacokinetics revealed that depatux-m exposures were approximately dose-proportional. CONCLUSIONS:Depatux-m resulted in infrequent nonocular AEs but increased ocular AEs. Patient follow-up confirmed that ocular AEs were reversible. Lowering the drug-antibody ratio did not decrease the number of ocular AEs. A partial response in 1 patient with EGFR-amplified disease provides the opportunity to study depatux-m in diseases with a high incidence of EGFR amplification. Cancer 2018;124:2174-83. © 2018 The Authors. Cancer published by Wiley Periodicals, Inc. on behalf of American Cancer Society. This is an open access article under the terms of the Creative Commons Attribution NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

Project description:Abstract BACKGROUND Depatuxizumab mafodotin (depatux-m, formerly ABT-414), is an antibody-drug conjugate comprised of an EGFR-targeted antibody, a non-cleavable linker maleimidocaproyl, and the microtubule inhibitor monomethylauristatin F. Promising antitumor activity of depatux-m was observed in patients with glioblastoma (GBM) in Phase 12 studies. Dosage of depatux-m is limited by ocular side effects (OSE), such as blurred vision, dry eye, and photophobia from corneal epitheliopathy, which are generally reversible after dose reduction or drug discontinuation. This Phase 3b study evaluates depatux-m-related OSE management strategies used in depatux-m clinical trials. METHODS This open-label study will enroll approximately 90 patients with newly diagnosed, histologically confirmed, grade IV GBM that is epidermal growth factor receptor (EGFR)-amplified. Patients will receive depatux-m during the chemoradiation phase (radiation and temozolomide [TMZ]), and during adjuvant therapy with TMZ. Patients are randomized to one of three prophylactic ocular treatments: standard steroids (SS), SS with vasoconstrictors and cold compress (VC), or enhanced steroids (ES) with VC. Primary objective is to evaluate these prophylactic strategies for their effect on the proportion of patients requiring a change in OSE management due to inadequate control of OSEs, defined as either a 3-line decline in visual acuity from baseline or Grade 3 OSE severity on the Corneal Epithelial Adverse Event (CEAE) activities of daily living-based scale. Inadequate control with initial prophylactic regimen will trigger a switch to the addition of bandage contact lenses (BCL). Secondary objective assesses change in OSE management due to inadequate control of OSEs by BCL, defined as percentage of patients with Grade 3 CEAE that will trigger transition of patient to investigator discretion regimen (depatux-m interruption/dose reduction, VC prophylaxis, or ES prophylaxis). ClinicalTrials.gov: NCT03419403.

Project description:Abstract Background: Recurrent GBM (rGBM) has dismal prognosis. Almost 50% GBM tumors harbor amplified (amp) EGFR. ABT-414 is a tumor specific ADC combining an antibody targeting a unique conformation of EGFR (ABT-806) to a microtubule cytotoxin, monomethyl auristatin F (MMAF). Here we report the safety and efficacy of ABT-414 monotherapy at recommended phase 2 dose (RPTD) in EGFR amp, rGBM. Methods: M12-356 (NCT01800695) is an open-label, phase 1, 3-arm study: Arm A (ABT-414+radiation/temozolomide (TMZ) in newly diagnosed GBM (nGBM)), Arm B (ABT-414+TMZ in nGBM as adjuvant therapy, or in rGBM) and Arm C (ABT-414 monotherapy in rGBM). Each arm had an escalation cohort to determine the RPTD and an expansion cohort to establish the safety and preliminary efficacy at RPTD. Results of Arm C expansion cohort at 1.25?mg/kg RPTD (IV infusion) are shown here. Eligible patients (pts) were adults with KPS score ?70, EGFR amp (confirmed centrally), rGBM, normal end-organ function and no prior bevacizumab. Results: As of January 7, 2016, 48 EGFR amp, rGBM pts were treated in this cohort. The median age was 59 years (range, 35–80). Most pts had prior therapies: 40% had 1, 48% had 2, 10% had ?3 prior therapies. Most common treatment emergent adverse events (TEAEs) (?25% pts) were blurred vision (60%), headache, photophobia (29% each), dry eye, eye pain, fatigue (27% each). The most common serious AE (>1 pt) was seizure (8%). Grade 3/4 TEAEs (>1 pt) were keratitis (15%), corneal epithelial microcysts (8%), hemiparesis, hyperglycemia, muscular weakness, seizure (6% each), blurred vision, ulcerative keratitis (4% each). No dose-limiting toxicities were reported. Best RANO responses of 44 pts with complete data were: 2 partial responses, 18 stable disease, 24 progressive disease. The 6-month progression-free survival (PFS6) estimate was 30% [95% CI=17, 44]. Conclusions: ABT-414 monotherapy, at 1.25?mg/kg RPTD, displayed frequent yet reversible ocular toxicities. An encouraging tumor stability/response and PFS6 were observed in this highly refractory EGFR amp, rGBM. A global randomized trial of ABT-414, alone or with TMZ, vs. TMZ or lomustine, is underway in EGFR amp, rGBM (NCT02343406).

Project description:Abstract Glioblastoma (GBM) is the most common and aggressive primary brain cancer. Current standard-of-care includes surgery, radiation and treatment with temozolomide (TMZ), however nearly all tumors recur and the prognosis for recurrent GBM is dismal. Resistance to TMZ is correlated with expression of the DNA repair enzyme O6-methylguanine-DNA-methyltransferase (MGMT), which is highly expressed in a majority of GBM tumors. Dianhydrogalactitol (VAL-083) is a first-in-class bi-functional DNA-targeting agent that exhibited activity against GBM in NCI-sponsored clinical trials both as a single agent and in combination with radiotherapy. VAL-083 readily crosses the blood-brain barrier and accumulates in brain tumor tissue. We have demonstrated that VAL-083 targets N7-Guanine and rapidly induces interstrand DNA cross-links, leading to DNA double-strand breaks, S/G2 cell-cycle arrest and cell death in GBM cell lines and GBM cancer stem cells (CSCs) in vitro. This unique N7-guanine targeting mechanism not only circumvents MGMT-mediated chemo-resistance but also maintains cytotoxic activity in cancer cells deficient in mismatch repair (MMR). These data suggest VAL-083 may offer a superior chemotherapeutic alternative in the treatment of MGMT-unmethylated or MMR deficient GBM. Here, we provide an update of ongoing clinical trials with VAL-083 in MGMT-unmethylated GBM: i) a single-arm, biomarker-driven, Phase II study to determine if VAL-083 treatment of MGMT-unmethylated adult GBM patients at first recurrence/progression, prior to bevacizumab improves survival compared to historical lomustine control (clinicaltrials.gov identifier: NCT02717962); ii) a single-arm, biomarker-driven, Phase II study to confirm the tolerability and efficacy of VAL-083 in combination with radiotherapy in newly diagnosed MGMT-unmethylated GBM patients (clinicaltrials.gov identifier: NCT03050736). The results of these studies may support a new treatment paradigm in for the treatment of MGMT-unmethylated GBM.

Dataset Information

ACTR-68. CONCORDANCE OF EGFR AND MGMT ANALYSES BETWEEN LOCAL AND CENTRAL LABORATORIES: IMPLICATIONS FOR CLINICAL TRIAL DESIGN AND PRECISION MEDICINE FOR DEPATUXIZUMAB-MAFODOTIN (ABT-414) IN GLIOBLASTOMA (GBM)

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets