Scott M. Hynes

Phase I Study of LY2606368, a Checkpoint Kinase 1 Inhibitor, in Patients With Advanced Cancer

PURPOSE The primary objective was to determine safety, toxicity, and a recommended phase II dose regimen of LY2606368, an inhibitor of checkpoint kinase 1, as monotherapy. PATIENTS AND METHODS This phase I, nonrandomized, open-label, dose-escalation trial used a 3 + 3 dose-escalation scheme and included patients with advanced solid tumors. Intravenous LY2606368 was dose escalated from 10 to 50 mg/m(2) on schedule 1 (days 1 to 3 every 14 days) or from 40 to 130 mg/m(2) on schedule 2 (day 1 every 14 days). Safety measures and pharmacokinetics were assessed, and pharmacodynamics were measured in blood, hair follicles, and circulating tumor cells. RESULTS Forty-five patients were treated; seven experienced dose-limiting toxicities (all hematologic). The maximum-tolerated doses (MTDs) were 40 mg/m(2) (schedule 1) and 105 mg/m(2) (schedule 2). The most common related grade 3 or 4 treatment-emergent adverse events were neutropenia, leukopenia, anemia, thrombocytopenia, and fatigue. Grade 4 neutropenia occurred in 73.3% of patients and was transient (typically < 5 days). Febrile neutropenia incidence was low (7%). The LY2606368 exposure over the first 72 hours (area under the curve from 0 to 72 hours) at the MTD for each schedule coincided with the exposure in mouse xenografts that resulted in maximal tumor responses. Minor intra- and intercycle accumulation of LY2606368 was observed at the MTDs for both schedules. Two patients (4.4%) had a partial response; one had squamous cell carcinoma (SCC) of the anus and one had SCC of the head and neck. Fifteen patients (33.3%) had a best overall response of stable disease (range, 1.2 to 6.7 months), six of whom had SCC. CONCLUSION An LY2606368 dose of 105 mg/m(2) once every 14 days is being evaluated as the recommended phase II dose in dose-expansion cohorts for patients with SCC.

Disposition and metabolism of LY2603618, a Chk-1 inhibitor following intravenous administration in patients with advanced and/or metastatic solid tumors

Abstract 1. The disposition and metabolism of a Chk-1 inhibitor (LY2603618) was characterized following a 1-h intravenous administration of a single 250-mg dose of [14C]LY2603618 (50 µCi) to patients with advanced or metastatic solid tumors. 2. LY2603618 was well tolerated with no clinically significant adverse events. Study was limited to three patients due to challenges of conducting ADME studies in patients with advanced cancer. Plasma, urine and feces were analyzed for radioactivity, LY2603618 and metabolites. LY2603618 had a half-life of 10.5 h and was the most abundant entity in plasma, accounting for approximately 69% of total plasma radioactivity. The second most abundant metabolites, H2 and H5, accounted for <10% of total circulating radioactivity. The major route of clearance was via CYP450 metabolism. The mean total recovery of radioactivity was 83%, with approximately 72% of the radioactivity recovered in the feces and approximately 11% in the urine. LY2603618 represented approximately 6% and 3% of the administered dose in feces and urine, respectively. 3. A total of 12 metabolites were identified. In vitro phenotyping indicated that CYP3A4 was predominantly responsible for the metabolic clearance of LY2603618. Additionally, aldehyde oxidase was involved in the formation of a unique human and non-human primate metabolite, H5.

A randomized, phase 2 evaluation of the CHK1 inhibitor, LY2603618, administered in combination with pemetrexed and cisplatin in patients with advanced nonsquamous non‐small cell lung cancer

This phase 2 portion of a phase 1/2 study examined the efficacy and safety of LY2603618, a selective checkpoint kinase 1 inhibitor, combined with pemetrexed and cisplatin (LY+Pem+Cis) in patients with advanced nonsquamous non-small cell lung cancer (NSCLC). This multicenter, randomized, controlled, open-label study (NCT01139775) enrolled patients with stage IV nonsquamous NSCLC and an Eastern Cooperative Oncology Group performance status ≤1. Patients were randomized (2:1) to LY+Pem+Cis or pemetrexed and cisplatin (Pem+Cis). Induction therapy comprised four 21-day cycles of 500 mg/m2 pemetrexed and 75mg/m2 cisplatin on Day 1 (both arms) and 275mg LY2603618 on Day 2 (LY+Pem+Cis arm). Maintenance therapy comprised 500mg/m2 pemetrexed on Day 1 (both arms) and 275mg LY2603618 on Day 2 (LY+Pem+Cis arm) until disease progression. The primary endpoint was progression-free survival (PFS). Enrollment was permanently halted before target enrollment was met due to a greater number of thromboembolic events in the LY+Pem+Cis arm. Sixty-two patients were enrolled (LY+Pem+Cis, n=39; Pem+Cis, n=23). Bayesian and frequentist analysis demonstrated superior PFS in the LY+Pem+Cis arm vs the Pem+Cis arm (median [90% confidence interval]: LY+Pem+Cis, 4.7 months [4.-7.1]; Pem+Cis, 1.5 months [1.3-2.9]; P=0.022). Seven patients in the LY+Pem+Cis arm (vs 0 in the Pem+Cis arm) experienced serious thromboembolic events: pulmonary embolism (n=5), ischemic stroke (n=1), and cerebrovascular accident (n=1). Although the primary endpoint was met, the combination of LY2603618+Pem+Cis will not be further developed for treating advanced nonsquamous NSCLC due to the potential increased risk of thromboembolic events with this combination. ClinicalTrials.gov Identifier: NCT01139775.

Evaluation of the likelihood of a selective CHK1 inhibitor (LY2603618) to inhibit CYP2D6 with desipramine as a probe substrate in cancer patients

LY2603618 is a selective inhibitor of deoxyribonucleic acid damage checkpoint kinase 1 (CHK1) and has been in development for the enhancement of chemotherapeutic agents. The study described was to assess the potential interaction between LY2603618 and cytochrome P450 isoform 2D6 (CYP2D6) substrate desipramine in patients with cancer. Before clinical investigation, in silico simulations (using Simcyp®) were conducted. An open‐label, two‐period, fixed‐sequence study was planned in 30 patients with advanced or metastatic cancers, in which a 50 mg oral dose of desipramine was administered alone and in combination with 275 mg of LY2603618 (i.v. infusion). An interim analysis was planned after 15 patients completed both periods. Ratios of geometric least squares means (LSMs) of primary pharmacokinetic (PK) parameters and 90% repeated confidence intervals (RCIs) between desipramine plus LY2603618 and desipramine alone were calculated. Lack of an interaction was declared if the 90% RCI fell between 0.8 and 1.25. The LSM ratios (90% RCI) for areas under the plasma concentration–time curve from time zero to tlast (AUC[0‐tlast]) and to infinity (AUC[0‐∞]) and maximum plasma concentration (Cmax) were 1.14 (1.04, 1.25), 1.09 (0.99, 1.21) and 1.16 (1.05, 1.29). In silico simulations were predictive of clinical results. Single doses of 275 mg LY2603618 administered with 50 mg desipramine were generally well tolerated. In conclusion, no clinically significant interaction was observed between LY2603618 and desipramine in patients with cancer. In silico predictions of clinical results demonstrated that mechanistic and physiologically based PK approaches may inform clinical study design in cancer patients. Copyright

Abstract A94: Dose determination of LY2603618, a Chk1 inhibitor, administered in combination with gemcitabine in patients with advanced cancer.

Background: LY2603618 is a selective inhibitor of Chk1, a protein kinase that plays a key role in the DNA damage checkpoint. Inhibition of Chk1 is predicted to enhance the effects of antimetabolites, such as gemcitabine. Methods: This study is a Phase 1–2 study in patients with solid tumors (Phase 1) and advanced pancreatic adenocarcinoma (Phase 2). In Phase 1, gemcitabine (1000 mg/m2) was administered on Days 1, 8, and 15 of a 28-day cycle. LY2603618 was administered on Days 2, 9, and 16. Patients were assessed for safety, tolerability, and dose-limiting toxicity (DLT). A recommended Phase 2 dose (RP2D) was determined based on safety, dose intensity, and pharmacokinetics (PK). Results: A total of 50 patients were enrolled. Patients were treated at 70 (n =3), 105 (n=3), 150 (n=7), 200 (n=11), 250 (n=6) mg/m2and at 2 additional flat-fixed dose cohorts of 200 (n=10) and 230 (n=10) mg. The most frequent AEs reported included fatigue, thrombocytopenia, anemia, nausea, neutropenia, and constipation, which are consistent with those reported with gemcitabine monotherapy. During escalation, DLTs included neutropenia, infusion-related reaction and thrombocytopenia, with thrombocytopenia being dose limiting. The maximum tolerated dose (MTD) was determined to be 200 mg/m2. The systemic exposure of LY2603618 increased in a dose-dependent manner and the LY2603618 systemic clearance was dose-independent across all doses on average. The mean LY2603618 half-life varied across doses but was consistent with a half-life (i.e., >10 hr and 21,000 ng hr/mL and Cmax > 2000 ng/mL) were achieved by all but one patient. Based on safety/tolerability, the ability to maintain dose intensity, and PK, a RP2D of 230 mg was selected. A total of 17 of 30 patients received more than 2 cycles of therapy. Conclusions: LY2603618 administered in combination with gemcitabine demonstrated an acceptable safety profile; the MTD for this regimen was defined at 200 mg/m2 in the originally designed study. However at a fixed dose of 230 mg, LY2603618 in combination with gemcitabine had an acceptable safety profile and the observed exposures exceed those required for biological effect in nonclinical models. This dose is being evaluated in the Phase 2 component of the study. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A94.

Correction to: A phase I study of LY3164530, a bispecific antibody targeting MET and EGFR, in patients with advanced or metastatic cancer

The original version of this article unfortunately contained a mistake. The co-authors’ names were incorrect.

Abstract LB-200: Dose and schedule determination of the Chk1/2 inhibitor LY2606368 in patients with solid tumors.

Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC Background: LY2606368 mesylate hydrate (LY2606368) is a Chk1/2 inhibitor. In addition to its role in DNA damage response, Chk1 also phosphorylates multiple downstream targets that regulate DNA replication, chromosome alignment, spindle checkpoints, and exit from cytokinesis. Since potent inhibition of Chk1 is predicted to generate DNA damage and mitotic catastrophe, this study evaluated LY2606368 as a single agent. Methods: Two schedules of LY2606368 were assessed in this dose escalation study: dosing on days 1-3 every 14 days (Schedule [Sch] 1) and dosing on day 1 every 14 days (Sch 2). Patients were assessed for safety, tolerability, pharmacokinetics (PK), pharmacodynamic (PD), and dose-limiting toxicities (DLT). Results: A total of 45 patients were enrolled, 27 of which were treated on Sch 1 at doses of 10-50 mg/m2 while 18 patients were treated on Sch 2 at doses of 40-130 mg/m2. The most frequently reported AE, regardless of schedule, was a transient (typically < 5 days) decrease in neutrophil count, which occurred in 93% of patients (Grade 4 in 73% of patients). A total of 3 patients (6.7%) experienced febrile neutropenia. Other common toxicities, regardless of causality, included white blood cell decrease (84%), anemia (73%), fatigue (56%), platelet count decreased (53%), nausea (36%), constipation (29%), anorexia (27%), vomiting (27%), dyspnea (20%), and fever (20%). The majority of the non-hematologic toxicities were CTCAE Grade 1/2 in severity. Hematologic toxicity was the dose limiting toxicity on both schedules. The MTD for Sch 1 was 40 mg/m2 and for Sch 2 was 105 mg/m2. The systemic exposure of LY2606368 increased in a dose-dependent manner across the dose range of 10-130 mg/m2 for both schedules. The LY2606368 half-life is suitable for achieving acceptable exposure while minimizing intra- and intercycle accumulation for either schedule. The exposure at MTD for both schedules is in the range that correlates to the minimal tumor response in nonclinical xenograft models. The nonclinical PK/PD model predicts an average pChk1% inhibition of ∼50% and ∼70% for 72 hours is required for minimum and maximum tumor responses, respectively. Simulations of human PK/PD profiles predict that the exposure and average pChk1% inhibition at the MTD of each schedule achieve the requirements for the minimum tumor response. One patient with SCC of the anus achieved a PR (60% reduction). Ten of the 45 patients (22%) achieved SD including 4/7 (57%) HNSCC patients (range on treatment: 3-7.5mo) that had received multiple prior therapies. Conclusions: Based on the nonclinical PK/PD model, clinical human PK, human PD simulations, the similar safety profile, and the increased patient convenience, a dose of 105 mg/m2 of LY2606368, administered once every 14 days was selected as the schedule to further evaluate in Part B of the study, a dose expansion component which will focus on patients with squamous histology tumors. Citation Format: Johanna C. Bendell, Filip Janku, Jeffrey Infante, Suzanne Jones, Howard Burris, Lisa Golden, Scott M. Hynes, Ji Lin, Aimee K. Bence, Susan Tse, Razelle Kurzrock, David Hong. Dose and schedule determination of the Chk1/2 inhibitor LY2606368 in patients with solid tumors. [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-200. doi:10.1158/1538-7445.AM2013-LB-200

Abstract A86: A phase 1 study of LY2523355, an Eg5 inhibitor, administered on Days 1, 2, and 3 with or without pegfilgrastim in patients with advanced malignancy (NCT01214629).

Background: LY2523355 is a potent allosteric inhibitor of the motor protein Eg5 which selectively inhibits bipolar mitotic spindle formation. The objective of this Phase 1 study was to determine a Phase 2 dose and schedule of LY2523355 that may be safely administered to patients with advanced malignancy. Methods: Study I1Y-MC-JFBA is an open-label, multicenter, dose-escalation study in patients with advanced malignancy. A modified 3+3 dose-escalation scheme was used, followed by a dose confirmation phase with pre- and post-treatment tumor biopsies. Patients received LY2523355 as a 1hr infusion on days 1, 2 and 3 of a 21-day cycle with determination of the MTD with and without pegfilgrastim administration on day 4. Patients were assessed every other cycle by RECIST. Treatment related PD changes in phosphohistone H3 (pHH3) and Eg5 expression were assessed in skin and tumor biopsies by immunohistochemistry. Results: 46 patients were enrolled in the study as of October 2010. The most frequent related AEs reported (>10%) include leukopenia, neutropenia, fatigue, nausea, stomatitis, vomiting, alopecia, anemia, diarrhea, lymphopenia, pruritis/itching and rash. Dose-limiting toxicities include increased INR, leukopenia, diarrhea, rash (palmar plantar erythrodysesthesia), febrile neutropenia, and mucositis. The single and multiple dose pharmacokinetics of LY2523355 and metabolite were characterized. Dose dependent increase in LY2523355 plasma exposure and a minor degree of intra- and inter-cycle accumulation were observed. An exposure-dependent increase in pHH3 and Eg5 expression and increase in apoptotic cells in tumor and skin biopsies has been demonstrated. One patient with ovarian cancer had a confirmed partial response. Nine other patients had stable disease for at least 2 cycles. Conclusions: The MTD of LY2523355 for this schedule has been established with and without pegfilgrastim at 6mg/m 2 /d and 4 mg/m 2 /d, respectively. These doses have shown a quantifiable PD response in skin and tumor biopsies confirming the importance of maximizing exposure intensity for maximum PD response. Dose confirmation is on-going. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A86.