McGovern, Renee M.

Abstract WSD0922-Fu is an oral, CNS-penetrant, small molecule EGFR inhibitor which potently inhibits EGFR aberrations specific to non-small cell lung cancer (NSCLC) and high-grade astrocytoma (HGA). MC1914 (NCT04197934) is a first-in-human phase 1 trial in patients with EGFR aberrant recurrent HGA and NSCLC. Adult patients with either recurrent EGFR mutant NSCLC with CNS metastases or recurrent EGFR aberrant HGA were enrolled and treated across six cohorts (40 mg once daily to 320 mg twice daily, 28-day cycles) to determine the maximum tolerated dose (MTD). 25 patients (17 HGA, 8 NSCLC) were enrolled (median age = 57 years; 24% female; 36% ECOG 0). All patients with HGA received prior radiation and temozolomide. All patients with NSCLC had previous disease progression on EGFR inhibitor therapy (prior osimertinib 88%). The median duration of WSD0922-Fu exposure among all patients was 55 days (range 3 to >279 days) [NSCLC median = 131 days; HGA median = 51 days]. Common treatment-related adverse events are comparable to other EGFR inhibitors (fatigue, acneiform rash, diarrhea, nausea, pruritis). At Cycle 1 Day 15 for patients treated at MTD (160 mg twice daily), the mean terminal elimination half-life (%CV) in the plasma was 31.6 h (102%) (median 14.5 h). The mean Cmax, Tmax, oral clearance at steady state, and AUC (0-12 h) (%CV) were 4513 ng/mL (50%), 2.0 hr (69%), 6.9 L/hr/m2 (42%), and 28084 h*ng/mL (52%), respectively. Among patients with NSCLC treated at MTD or higher dose levels and with available response data, 100% (5/5) of patients demonstrated clinical benefit (SD + PR) while 60% of patients had partial responses. Intracranial and extracranial efficacy was concordant. Furthermore, prolonged stable disease (9 cycles) was observed in a patient with EGFRvIII mutant GBM. Expansion cohorts are in progress to optimize WSD0922-Fu dose and schedule for future phase 2 development.

AbstractThe purpose of this study was to develop and validate a population pharmacokinetic model for Z‐endoxifen in patients with advanced solid tumors and to identify clinical variables that influence pharmacokinetic parameters. Z‐endoxifen‐HCl was administered orally once a day on a 28‐day cycle (±3 days) over 11 dose levels ranging from 20 to 360 mg. A total of 1256 Z‐endoxifen plasma concentration samples from 80 patients were analyzed using nonlinear mixed‐effects modeling to develop a population pharmacokinetic model for Z‐endoxifen. A 2‐compartment model with oral depot and linear elimination adequately described the data. The estimated apparent total clearance, apparent central volume of distribution, and apparent peripheral volume of distribution were 4.89 L/h, 323 L, and 39.7 L, respectively, with weight‐effect exponents of 0.75, 1, and 1, respectively. This model was used to explore the effects of clinical and demographic variables on Z‐endoxifen pharmacokinetics. Weight, race on clearance, and aspartate aminotransferase on the absorption rate constant were identified as significant covariates in the final model. This novel population pharmacokinetic model provides insight regarding factors that may affect the pharmacokinetics of Z‐endoxifen and may assist in the design of future clinical trials.

ObjectiveEpalrestat, an aldose reductase inhibitor increases phosphomannomutase (PMM) enzyme activity in a PMM2‐congenital disorders of glycosylation (CDG) worm model. Epalrestat also decreases sorbitol level in diabetic neuropathy. We evaluated the genetic, biochemical, and clinical characteristics, including the Nijmegen Progression CDG Rating Scale (NPCRS), urine polyol levels and fibroblast glycoproteomics in patients with PMM2‐CDG.MethodsWe performed PMM enzyme measurements, multiplexed proteomics, and glycoproteomics in PMM2‐deficient fibroblasts before and after epalrestat treatment. Safety and efficacy of 0.8 mg/kg/day oral epalrestat were studied in a child with PMM2‐CDG for 12 months.ResultsPMM enzyme activity increased post‐epalrestat treatment. Compared with controls, 24% of glycopeptides had reduced abundance in PMM2‐deficient fibroblasts, 46% of which improved upon treatment. Total protein N‐glycosylation improved upon epalrestat treatment bringing overall glycosylation toward the control fibroblasts’ glycosylation profile. Sorbitol levels were increased in the urine of 74% of patients with PMM2‐CDG and correlated with the presence of peripheral neuropathy, and CDG severity rating scale. In the child with PMM2‐CDG on epalrestat treatment, ataxia scores improved together with significant growth improvement. Urinary sorbitol levels nearly normalized in 3 months and blood transferrin glycosylation normalized in 6 months.InterpretationEpalrestat improved PMM enzyme activity, N‐glycosylation, and glycosylation biomarkers in vitro. Leveraging cellular glycoproteome assessment, we provided a systems‐level view of treatment efficacy and discovered potential novel biosignatures of therapy response. Epalrestat was well‐tolerated and led to significant clinical improvements in the first pediatric patient with PMM2‐CDG treated with epalrestat. We also propose urinary sorbitol as a novel biomarker for disease severity and treatment response in future clinical trials in PMM2‐CDG. ANN NEUROL 20219999:n/a–n/a

AbstractHigh‐dose methotrexate (HDMTX) pharmacokinetics (PKs), including the best estimated glomerular filtration rate (eGFR) equation that reflects methotrexate (MTX) clearance, requires investigation. This prospective, observational, single‐center study evaluated adult patients with lymphoma treated with HDMTX. Samples were collected at predefined time points up to 96 h postinfusion. MTX and 7‐hydroxy‐MTX PKs were estimated by standard noncompartmental analysis. Linear regression determined which serum creatinine‐ or cystatin C‐based eGFR equation best predicted MTX clearance. The 80 included patients had a median (interquartile range [IQR]) age of 68.6 years (IQR 59.2–75.6), 54 (67.5%) were men, and 74 (92.5%) were White. The median (IQR) dose of MTX was 7.6 (IQR 4.8–11.3) grams. Median clearance was similar across three dosing levels at 4.5–5.6 L/h and was consistent with linear PKs. Liver function, weight, age, sex, concomitant chemotherapy, and number of previous MTX doses did not impact clearance. MTX area under the curve (AUC) values varied over a fourfold range and appeared to increase in proportion to the dose. The eGFRcys (ml/min) equation most closely correlated with MTX clearance in both the entire cohort and after excluding outlier MTX clearance values (r = 0.31 and 0.51, respectively). HDMTX as a 4‐h infusion displays high interpatient pharmacokinetic variability. Population PK modeling to optimize MTX AUC attainment requires further evaluation. The cystatin C‐based eGFR equation most closely estimated MTX clearance and should be investigated for dosing and monitoring in adults requiring MTX as part of lymphoma management.

AbstractThe application of scaffold‐based stem cell transplantation to enhance peripheral nerve regeneration has great potential. Recently, the neuroregenerative potential of tacrolimus (a U.S. Food and Drug Administration‐approved immunosuppressant) has been explored. In this study, a fibrin gel‐based drug delivery system for sustained and localized tacrolimus release was combined with rat adipose‐derived mesenchymal stem cells (MSC) to investigate cell viability in vitro. Tacrolimus was encapsulated in poly(lactic‐co‐glycolic) acid (PLGA) microspheres and suspended in fibrin hydrogel, using concentrations of 0.01 and 100 ng/ml. Drug release over time was measured. MSCs were cultured in drug‐released media collected at various days to mimic systemic exposure. MSCs were combined with (i) hydrogel only, (ii) empty PLGA microspheres in the hydrogel, (iii) 0.01, and (iv) 100 ng/ml of tacrolimus PLGA microspheres in the hydrogel. Stem cell presence and viability were evaluated. A sustained release of 100 ng/ml tacrolimus microspheres was observed for up to 35 days. Stem cell presence was confirmed and cell viability was observed up to 7 days, with no significant differences between groups. This study suggests that combined delivery of 100 ng/ml tacrolimus and MSCs in fibrin hydrogel does not result in cytotoxic effects and could be used to enhance peripheral nerve regeneration.

Abstract Prior in vitro work in the human hepatoma cell lines Huh7 and HEP3B indicated that combination treatment of the BH3 mimetic, navitoclax, and the multi-kinase inhibitor, sorafenib, was more effective at inducing apoptosis than either compound alone. This current study was part of a phase I clinical trial to determine the maximum tolerated dose of concurrent navitoclax and sorafenib treatment in patients with relapsed or refractory solid organ tumors and sought to characterize the pharmacokinetics (PK) and pharmacodynamics (PD) of both agents in combination. Cleavage of cytokeratin 18 by caspase 3 was used as a biomarker for therapy-induced activation of apoptosis to determine if combination treatment results in an increase in apoptosis as previously observed in in vitro work. PK were assessed in 26 patients (ages 32 - 80) enrolled in a phase I clinical trial (NCT02143401). 150 mg of oral navitoclax was administered once daily for a seven day run-in (beginning Day -7) prior to 150 mg (Dose level 1) or 200 mg (Dose level 2) navitoclax concomitant treatment with 400 mg of twice daily oral sorafenib (Day 1). Samples for pharmacokinetic analysis were obtained on Day -7 and Day 1 prior to dosing and at 1, 2, 4, 8-12, and 24 hours post dosing. PK parameters were estimated by noncompartmental analysis using Phoenix® WinNonlin® Version 6.4. To examine the PD of both agents in combination, cytokeratin 18 cleavage was quantified by ELISA after the 7-day navitoclax run-in and on Day 2 or 4 and Day 8 of navitoclax and sorafenib combination treatment. PK estimates of maximum concentration, exposure, volume of distribution, and clearance for navitoclax on Day -7 and Day 1 were not significantly different, indicating a lack of navitoclax accumulation. Finally, no correlation was found between navitoclax exposure and apoptosis as indicated by cytokeratin-18 cleavage. This work was supported by the NCI Cancer Center Support Grant P30 CA15083 and NCI Experimental Therapeutics Phase I Grant UM1 CA186686. Citation Format: Emily J. Koubek, Brian A. Costello, Jun Yin, Renee M. McGovern, Sarah A. Buhrow, Renee A. Schoon, Carrie A. Strand, Yixing Jiang, Mitesh J. Borad, Naoko Takebe, Scott H. Kaufmann, Alex A. Adjei, Joel M. Reid. Pharmacokinetic analysis of navitoclax in combination with sorafenib in patients with relapsed or refractory solid organ tumors [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT114.

Abstract Background: Endx is a Tam metabolite with promising antitumor activity in Tam and aromatase inhibitor (AI) resistant estrogen receptor (ER) positive (+) metastatic breast cancer (MBC). Methods: This randomized phase II study compared progression-free survival (PFS) and toxicity of Endx 80 mg/day to Tam 20 mg/day in patients (pts) with ER+ MBC. Eligibility included postmenopausal women, ECOG PS 0-2, prior progression on AI but not Tam (unlimited endocrine therapy [ET] lines allowed), and a preregistration biopsy confirming ER+ (>10% nuclear staining) and HER2-negative MBC. Stratified randomization was used balancing prior CDK 4/6 inhibitor (CDK 4/6i) use and/or everolimus (yes/no), measurable disease (yes/no) and endocrine resistance (primary/secondary) between arms. Pts randomized to Tam were allowed to cross over to Endx at progression. Due to short expected median PFS, differences in PFS were assessed using approaches for interval-censored data (ICD). 40 eligible pts were to be randomized to each arm so a one-sided alpha=0.10 generalized log-rank test (GLRT) would have a 90% chance of detecting a 50% decrease in hazard of disease progression with Endx (median: 6 months) relative to Tam (median: 3 months). Secondary endpoints include clinical benefit rate (stable or partial response > 6 cycles) (CBR) for measurable and non-measurable disease. Pharmacokinetic (PK) data were obtained Day (d) 1 (4 hour), end of cycle 2, and at time of progression. Results: From March 2015 to March 2017, 108 women with endocrine refractory recurrent or MBC were preregistered. 27 pts did not register due to: biopsy demonstrating ER-/HER2- (3 pts), ER+/HER2+ (5 pts), cancer other than breast (3 pts), no cancer in specimen (6 pts), brain metastases (2 pts), acute infection (1 pt), progression on or recent use of Tam (2 pts), or pt refusal (5 pts). 4/81 pts who registered were excluded due to ineligibility (3 pts) or refusal to start protocol treatment (1 pt). The study cohort consisted of 40 pts randomized to Endx and 37 pts to Tam. The median (m) number of ETs in the metastatic setting was 2 (range 1-4) for each arm including prior CDK 4/6i (Endx: 42.5%, Tam: 29.7%) and everolimus (Endx: 35.0%, Tam: 40.5%). The m cycle number was 6 for Endx (range: 1-35) and 3 for Tam (range: 1-42). PFS for Endx was not significantly different compared to Tam (HR= 0.77; 95% CI: 0.49-1.22, GLRT p=0.309; mPFS: Endx 130 days [95% CI: 76-138 days] and Tam 42 days [95%CI: 24-129 days]). However, PFS was significantly longer in pts with no prior CDK 4/6i in the Endx arm (GLRT p=0.002; HR(no/yes)=0.31; 95%CI: 0.15-0.65) but not in the Tam arm (GLRT p=0.708) (unplanned analysis). Severe (grade (G) 3+) toxicities included: Endx G3 hypertriglyceridemia (3 pts); Tam: G3 hypertension with G2 stroke (1 pt), G3 thromboembolic event (1 pt), and G3 abdominal, bone and liver pain (1 pt). In Endx arm, d1 m Endx plasma concentration (conc) was 216 ng/ml (n=17; range: 144-400). For Tam arm, d1 m Tam conc was 17 ng/ml (n=17; range:11-23) (Endx not detectable). For the 25 pts that crossed over to Endx, CBR was 28.0% (90% CI: 14.0-46.2%) and 14 pts had pk data at progression. A lower median Endx conc (6 ng/ml range: 3.3-16.3) was observed in Tam patients at progression who then had Endx clinical benefit compared to Tam pts without clinical benefit after Endx crossover (median Endx 12 ng/ml; range 4.4-36.6).Conclusions: In endocrine-resistant breast cancer, Z-Endx was not significantly superior to Tam, but clinical benefit was observed in 28% that crossed over to Endx after Tam progression. In pts with no prior CDK 4/6i, the observation of significantly longer PFS in the Endx arm is hypothesis generating. Support: U10CA180821, U10CA180882, U24CA196171, U10CA180820 (ECOG-ACRIN), https://acknowledgments.alliancefound.org; Clinical Trials.gov Identifier:NCT02311933 Citation Format: Matthew P. Goetz, Vera J Suman, Joel M Reid, Mary Kuffel, Sarah A Buhrow, Renee M McGovern, John Black, Travis Dockter, William F Symmans, Minetta C Liu, John R Hawse, James Doroshow, Anna M Storniolo, Jerry M Collins, Howard Streicher, Matthew M Ames, James N Ingle, Ann Partridge, Lisa Carey. A randomized phase II trial of tamoxifen versus Z-endoxifen HCL in postmenopausal women with metastatic estrogen receptor positive, HER2 negative breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr PD7-06.

9581 Background: AKT, a serine threonine protein kinase, is activated downstream of phosphatidylinositol 3-kinase (PI3K) which transmits signals from cytokines, growth factors and oncoproteins to multiple targets. Activated AKT regulates survival, proliferation, and growth. The PI3K/AKT pathway is downstream of most of the common growth factor tyrosine kinase receptors in cancer, e.g., EGFR, HER2, IGFR, etc., and is a driver of tumor progression in many cancers. AKT protein kinase is activated in many pediatric solid tumors, including glioblastoma, malignant rhabdoid tumors, neuroblastoma, synovial sarcoma, rhabdomyosarcoma and medulloblastoma. MK2206, an oral allosteric AKT1, 2,3 inhibitor, has demonstrated antitumor activity in in vitro and in vivo cancer models.A phase I trial evaluating MK2206 was conducted in children with refractory solid tumors. Methods: Using a rolling-6 design, MK2206 was administered either once every 7 days (schedule 1), or once every other day (schedule 2) in a 28-day cycle. Serial PK studies were obtained on day 1, cycle 1 and trough samples were obtained on days 7, 14, 21 and 28. Biological studies included analysis of PI3K/PTEN/AKT-cell signaling pathway in pre and post-therapy in PBMC and in tumors at diagnosis or recurrence. Results: Forty-five patients [23 males, median age 13.6 years (range 3.1-21.9)] with malignant glioma (14), ependymoma (4), hepatocellular carcinoma (3), gliomatosis cereberi (2) or other tumors (22) were enrolled; 34 were fully evaluable for toxicity (schedule 1 n=17; schedule 2 n=17). Schedule 1 DLTs included: grade 3 dehydration in 1/6 patients at 28 mg/m2; grade 4 hyperglycemia and neutropenia in 1/6 patients at 45 mg/m2. There were no DLTs at 35 mg/m2 and dose level 4 (58 mg/m2) is currently open for patient accrual with one enrollment. Schedule 2 DLTs included: grade 3 alkaline phosphatase in 1/6 patients at 90 mg/m2; grade 3 rash in 1/6 patients at 120 mg/m2), and grade 3 rash in 2/6 patients at 155 mg/m2. Conclusions: The recommended pediatric phase II dose of weekly MK2206 is 120 mg/m2 and the last cohort of patients to the every other day dosing schedule of MMK206 is enrolling. PK and PD data are currently being analyzed and will be presented.

2039 Background: Vorinostat (V) is an oral inhibitor of histone deacetylase. In preclinical studies it inhibits growth of glioblastoma (GBM) cell lines and has supra-additive activity when combined with TMZ. Methods: The North American Brain Tumor Consortium (NABTC) is conducting a phase I study of V in combination with TMZ in patients with malignant gliomas (MG). Eligibility criteria are histologically proven GBM and anaplastic gliomas (AG) who have received radiotherapy and have not progressed on temozolomide, > 18 yrs old, life expectancy > 8 weeks, KPS > 60, adequate bone marrow reserve and organ function. There was no limitation to the type of antiepileptic drugs that could be used. All patients received TMZ at a dose of 150 mg/m2/day on days 1–5 days every 28 days. Variable doses of V were administered with food on days 1–14 every 28 days. Dose-limiting toxicities (DLT), determined during the first 4 weeks of therapy, were defined as any grade 4 hematologic toxicity except for grade 3 thrombocytopenia, and any grade 3 non-hematologic toxicities. Escalation was performed in standard groups of 3. The maximum tolerated dose (MTD) was defined as the dose at which DLTs occurred in no more than 1/6 patients. PKs were determined on cycle 1 for TMZ, V and its metabolites. Results: To date, 19 eligible patients have been enrolled (15 GBM; 4 AG). Patients’ characteristics are 11 male, 8 female; median age 54 yrs (36–78); median KPS 90 (70–100). DLTs were encountered at 300 mg bid of vorinostat (1 grade 3 thrombocytopenia; 1 grade 3 fatigue in 3 patients), 200 mg tid (1 grade 3 nausea, 1 grade 4 thrombocytopenia in 3 patients) and 200 mg twice daily (grade 3 fatigue in 2/6 patients). No DLTs were encountered in 6 patients receiving 300 mg daily. TMZ PKs included [n=16: Cmax 5.2 (± 1.55) μg/ml; AUC 20.1 (±4.66) μg x hr/ml; t1/2 1.9 (±0.32)/hr]. Vorinostat PKs (300mg dose level) were [n=4; Cmax 267 (±174) ng/ml; AUC0–8 603 (±197) ng x hr/ml]. The t1/2 for V and its glucuronide metabolite were identical (1.6 hrs) vs. 5.6 hrs for the acid metabolite. Conclusions: The MTD of vorinostat in combination with TMZ is 300 mg daily on days 1–14 every 28 days. Final PK results, and toxicities from an additional 10 patients enrolled at the MTD will be presented. [Table: see text]