Single Agent Dose Escalation Research Articles

A phase 1/2 study of the TBL1 inhibitor, tegavivint (BC2059), in patients (pts) with advanced hepatocellular carcinoma (aHCC) with β-catenin activating mutations.

TPS4192 Background: β-catenin mutations are present in up to 40% of aHCC pts. Elevated nuclear β-catenin expression levels correlate with poor responses to standard of care and β-catenin regulates both tumor metabolism and the immune microenvironment. Tegavivint is a first-in-class small molecule inhibitor of TBL1, a novel downstream Wnt-signaling pathway target. Tegavivint binds to TBL1 in the β-catenin pocket, disrupting the formation of the activation complex necessary for oncogenic activity, and enabling degradation of free nuclear β-catenin. The safety, clinical activity, and PK/PD of tegavivint was demonstrated through a proof-of-concept study in pts with desmoid tumors and is being studied through multiple Investigator Initiated Trials in AML (NCT04874480), pediatric solid tumors (NCT04851119), NSCLC (NCT04780568), and lymphoma (NCT05755087). Tegavivint was also studied in preclinical mouse models of β-cateninexon3 mutant HCC and the H22 syngeneic HCC model. In these models tegavivint decreased Wnt target gene expression and enhanced CD3+ T-cell infiltration in liver tumors. Tegavivint treatment of established β-cateninexon3 activated tumors resulted in reduced tumor growth and burden. Based on these promising preclinical results, the following phase 1/2 exploratory study was designed. Methods: This is a phase 1/2 study of tegavivint in pts with aHCC to characterize safety, PK/PD, and preliminary antitumor activity (NCT05797805). Eligibility includes aHCC pts ≥18 years old, with AXIN1or CTNNB1 mutation for all pts, except those in the single agent dose escalation; have BCLC Stage C or Stage B disease not amendable to local therapy or curative approaches, have Child-Pugh class A or B7 liver score, and must have received at least one prior line of systemic therapy. This study will be conducted in 2 parts. First, tegavivint will be administered as a single agent in a dose escalation/optimization and subsequent dose expansion cohort. Upon completion of the dose escalation via a 3+3 design, two dose levels will be selected for the dose selection optimization to determine the recommended phase 2 dose (RP2D) for use in the dose expansion. If sufficient clinical benefit is observed, the combination of tegavivint plus pembrolizumab will be explored in the second part of the study in aHCC pts previously treated with a PD-1/PD-L1 inhibitor. Tegavivint will be administered intravenously weekly. Primary objective is safety and secondary objectives are preliminary efficacy and PK/PD. The first patient began treatment in October of 2023 and the first dose escalation cohort was completed in January. Three institutions are open for enrollment; 5 other sites are pending site activation; all sites are in the United States and Canada. Clinical trial information: NCT05797805 .

ATTAINMENT: A phase Ib trial of MDX-124, a first-in-class annexin-A1 targeting antibody, alone and in combination with anti-cancer treatments, in patients with advanced solid tumors.

TPS2671 Background: Annexin-A1 is a Ca2+-dependent phospholipid binding protein that is secreted from both cancer and immune cells in response to several physiological stimuli. Secreted annexin-A1 activates formyl peptide receptors driving cancer cell proliferation, angiogenesis, migration, and drug resistance, as well as modulating the tumor microenvironment. Annexin-A1 overexpression is observed in multiple cancers, including pancreatic, triple-negative breast, colorectal, lung and prostate, correlating with poor prognosis and decreased overall survival. MDX-124 is a novel, first-in-class humanised monoclonal antibody that targets annexin-A1. It significantly reduces cancer cell growth via cell cycle arrest, inhibits tumour growth in-vivo, reduces metastasis and induces antibody-dependent cellular cytotoxicity in annexin-A1 expressing cancer cells. Additionally, MDX-124 has synergistic activity when combined with chemotherapy and immunotherapy in pre-clinical models. These data indicate blocking the action of annexin-A1 has anti-cancer and therapeutic activity. Methods: ATTAINMENT is a modular, multi-arm, First-in-Human trial to evaluate the safety and tolerability of MDX-124 alone and in combination with anti-cancer treatments, in participants with locally advanced, unresectable, or metastatic solid malignancies. Module 1 is a single agent dose escalation using a Bayesian optimal interval (BOIN) design with an expansion cohort, followed by Module 2, which will evaluate MDX-124 in combination with standard of care in indication-specific arms by using a traditional 3+3 dose escalation scheme. Adult patients (≥18 years) with ECOG performance score 0-1 and histologically/cytologically confirmed solid tumors believed to overexpress annexin-A1 which are not amenable to or refractory to standard therapy, or for which no standard therapy exists are eligible. The primary objective is to determine the recommended phase 2 dose (RP2D) of MDX-124 both as a single agent and in combination with anti-cancer treatments. Secondary objectives will assess the safety and tolerability of MDX-124 when given as a single agent or in combination with anti-cancer treatments, characterize pharmacokinetic parameters and assess evidence of preliminary anti-tumor activity per RECIST v1.1 criteria. Exploratory objectives will assess host immune response to MDX-124 (immunogenicity and immunophenotyping), circulating levels of annexin-A1 at baseline and after dosing to correlate with response and outcome to MDX-124, and the impact of MDX-124 on blood/tissue biomarkers. The study began enrolling patients at sites in the UK in August 2023. Cohorts at 1, 2.5 and 5 mg/kg have been completed without DLT and enrollment to cohort 4 (10 mg/kg) began in January 2024. Clinical trial information: ISRCTN78740398.

Abstract PO4-04-11: Exposure–response analyses of GO39932: a Phase Ia/b study of giredestrant in estrogen receptor-positive, HER2-negative, locally advanced or metastatic breast cancer

Abstract BACKGROUND Giredestrant (GIR) is a highly potent, nonsteroidal, oral, selective estrogen receptor antagonist and degrader (SERD). The Phase Ia/b GO39932 study (NCT03332797) investigated GIR ± palbociclib (palbo) and ± a luteinizing hormone-releasing hormone agonist for patients with ER-positive, HER2-negative, locally advanced or metastatic breast cancer who had disease progression on prior endocrine therapies. In the single-agent dose-escalation stage, patients received 10, 30, 90, or 250 mg of once-daily (QD) GIR. In the dose-expansion stage, patients received 30, 100, or 250 mg of QD GIR. Safety and tolerability of 100 mg GIR + 125 mg palbo was also explored in the dose-escalation and -expansion stages. Results showed that GIR was well tolerated and potentially clinically active as a single agent and in combination with palbo, including in patients with ESR1-mutated tumors. To inform the selection of the clinical dose for GIR late-stage development based on risk–benefit considerations, exposure–response (E–R) analyses for efficacy and safety endpoints were conducted using single-agent GIR data. METHODS Exposure metrics included maximum concentration at steady state and area under the concentration–time curve at steady state. The association between the exposure metrics and efficacy endpoints (objective response rate [ORR] and clinical benefit rate [CBR]) or safety endpoints (all adverse events [AEs], Grade ≥ 3 AEs, selected AEs of interest [sAEIs], including all-grade hepatotoxicity, and bradycardia) were evaluated. RESULTS Data cutoff was September 17, 2021. A total of 111 patients were enrolled in the single-agent GIR cohort. Of these 111 patients, 107 were pharmacokinetic-evaluable and included in the analysis. ORR in patients with measurable disease at baseline was 20% (16/81 patients) and CBR was 49% (54/111). No significant associations were observed between exposure and ORR or CBR, including in patients with ESR1-mutated tumors and those with no mutation detected (p > 0.05). There were 92/107 patients (86%) with AEs of any grade, overall. Seventy-two (67%) had sAEIs, 19 (18%) experienced hepatotoxicity (all events were reported as liver function test abnormalities), 11 (10%) had bradycardia, and 20 (19%) had Grade ≥ 3 AEs. Increasing exposure did not significantly increase the incidence of all AEs, Grade ≥ 3 AEs, sAEIs, or bradycardia at the dose range of 10 to 250 mg (p > 0.05). For hepatotoxicity, the analysis suggested that higher exposure may lead to a higher probability of events (p = 0.0065); however, at the clinically relevant exposure range for the 30 mg dose, the incidence of hepatotoxicity was low and the predicted exposures were at the shallower slope of the relationship. CONCLUSIONS Single-agent GIR did not exhibit a significant association between exposure and efficacy endpoints at a dose range of 10 to 250 mg, regardless of ESR1 mutation status, indicating that the efficacy of GIR might have reached a plateau at low dose levels. At the clinically relevant exposure range of the 30 mg dose, GIR exposure was not associated with an appreciable increase in the incidence of AEs. The Phase Ia/b study design and subsequent E–R results enabled dose selection to be based on risk–benefit considerations, rather than the traditional maximum tolerated dose paradigm, in line with the United States Food and Drug Administration’s oncology dose optimization recommendations. The E–R results also indicate that GIR may have a relevant wide therapeutic window. Overall, these data support the 30 mg clinical dose of GIR that was selected, with a favorable risk–benefit profile, for further clinical studies. Citation Format: Komal Jhaveri, Yi Ting (Kayla) Lien, Nicholas Turner, Elgene Lim, Maureen Cannon, Richard Anziano, Jurgen Langenhorst, Kenta Yoshida, Vikram Malhi, Mary Gates, Jennifer Eng-Wong, Chunze Li, Mona Shah, Pablo Perez-Moreno, Jiajie Yu, Aditya Bardia. Exposure–response analyses of GO39932: a Phase Ia/b study of giredestrant in estrogen receptor-positive, HER2-negative, locally advanced or metastatic breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-04-11.

Abstract PS17-01: Key drivers of therapeutic response and resistance to giredestrant from GO39932: a Phase Ia/b study in patients with estrogen receptor-positive, HER2-negative, locally advanced or metastatic breast cancer

Abstract BACKGROUND Several investigational oral selective estrogen receptor antagonists and degraders (SERDs) are under investigation. These were partly developed to benefit patients (pts) with breast cancer (BC) who acquired resistance to standard-of-care (SoC) endocrine therapies (ET); e.g., through gain of ESR1 mutations that enable estrogen-independent ER activity. One such SERD, giredestrant (G), demonstrates activity in pts with ESR1-wild type (WT) or -mutant (m) tumors, and in pts who progressed on other ETs. Results from Phase I/III trials in ER-positive, HER2-negative, locally advanced/metastatic BC (ER+, HER2– LA/mBC) showed that next-generation SERDs had increased activity in ESR1m tumors vs SoC ETs. However, enthusiasm was hindered by heterogeneous responses, driven in part by study design differences. Across acelERA BC (NCT04576455), EMERALD (NCT03778931), SERENA-2 (NCT04214288), and AMEERA-3 (NCT04059484), 30–50% of pts progressed rapidly (< 2 months) when treated with SoC ETs or next-generation SERDs, while others benefited for ≥ 1 year. We present an exploratory biomarker analysis aimed at understanding the mechanistic basis for heterogeneous responses to SERDs in ER+, HER2– LA/mBC, by assessing a Phase Ia/b G cohort (NCT03332797) with paired baseline and on-treatment (tx) biopsies. METHODS Pts had ≤ 2 prior therapies for LA/mBC; disease recurrence/progression while on adjuvant ET for ≥ 24 months and/or ET for ER+, HER2– LA/mBC; and tumor response/stable disease for ≥ 6 months. Single-agent dose-escalation stage: 10, 30, 90, or 250 mg G once daily (QD) on Days (D) 1–28 of 28-D cycles (C). Dose-expansion stage: 30, 100, or 250 mg G QD. 100 mg G + 125 mg palbociclib on a 21-D on/7-D off schedule was also explored. Pre-/perimenopausal pts received LHRH agonists. Paired pre- and on-tx (C2D8) tumor biopsies (n = 29) were immunolabeled for ER, progesterone receptor, and Ki67, and assessed via bulk RNA-sequencing. Pre-tx liquid biopsies (n = 85) were evaluated by FoundationOne Liquid CDx assay. To validate our clinical observations, we generated a SERD-resistant MCF7 cell line and tested its sensitivity to other therapies. RESULTS We compared fast-progressing pts (FP; progression-free survival [PFS] < 2 months) with those experiencing long-term benefit (LTB; PFS > 12 months). LTB was significantly associated with high tumor baseline ER pathway activity. Although the benefit of G was of larger magnitude among pts with ESR1m tumors compared with SoC ET in acelERA BC, here pts with predominantly ESR1WT tumors received LTB on G tx. At the molecular level, G acted on LTB tumors by suppressing cell cycle- and ER-associated genes. In contrast, G had no effect on the transcriptome of FP tumors, which had lower baseline ER activity than LTB tumors. FP tumors were instead enriched for multiple cancer-associated pathways, e.g., RAS/MAPK and PI3K, which may drive resistance to G and thus enable fast progression. By liquid biopsy, most FP pts (> 90%) did not harbor a mutation in the associated pathway (e.g., NF1, KRAS), and thus could not be identified by genomic profiling alone. FP tumors were instead enriched for multiple cancer-associated pathways by gene expression. We explored these mechanisms further in the SERD-resistant cell line, which was similarly enriched for EGFR and MAPK activation vs standard MCF7 cells. Although cells became resistant to ER-targeted drugs, they acquired sensitivity to EGFR/MAPK inhibitors e.g., gefitinib, cobimetinib. CONCLUSIONS We identified molecular features associated with LTB to G and revealed a set of oncogenic pathways associated with FP pts on tx; demonstrating that these pathways represent acquired dependencies and potential therapeutic targets for SERD-resistant tumors and FP pts. Citation Format: Jackson Liang, Christy Ong, Jennifer Giltnane, Junko Aimi, Ching-Wei Chang, Mary Gates, Jennifer Eng-Wong, Pablo Perez-Moreno, Komal Jhaveri, Elgene Lim, Nicholas Turner, Heather Moore. Key drivers of therapeutic response and resistance to giredestrant from GO39932: a Phase Ia/b study in patients with estrogen receptor-positive, HER2-negative, locally advanced or metastatic breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PS17-01.

Abstract A087: BI KRASmulti, a first-in-class, orally bioavailable and direct inhibitor of diverse oncogenic KRAS variants drives tumor regression in KRAS G12V-driven preclinical models

Abstract Alterations of KRAS are found in approximately one in seven of all human tumors, making KRAS one of the most prevalent oncogenic drivers. Gain-of-function missense mutations in KRAS, leading to its aberrant activation, are found in ~90% of pancreatic cancer, ~40% of colorectal cancer and ~30% of lung adenocarcinoma, with KRASG12V mutations accounting for ~28%, 9% and 6% of the cases, respectively. The poor outcome associated with these tumor types, particularly pancreatic cancer, as well as the lack of targeted inhibitors for KRASG12V calls for the urgent need to identify therapies able to effectively address the KRASG12V mutant allele. BI 3706674 is a novel, potent and orally available small molecule inhibitor of the KRAS oncogene. BI 3706674 binds non-covalently to multiple KRAS mutant alleles, including KRASG12V, in the GDP-bound state, and blocks downstream oncogenic signalling. Here, we show that BI 3706674 has a strong anti-proliferative activity in a panel of KRASG12V mutant cancer cell lines in vitro, along with significant pharmacodynamic (PD) biomarker modulation (including inhibition of ERK1/2 phosphorylation and down-regulation of DUSP6 mRNA).In vivo, a twice daily oral dose of 30 mg/kg was well-tolerated, while inducing tumour regression in several mutant KRASG12V cell line-derived and patient-derived xenograft (CDX and PDX) models across multiple different human tumor types. We have selected different non-small cell lung cancer xenograft models for extensive PK/PD/efficacy analysis in vivo. Results of the ongoing analysis will be shared. Feedback activation of upstream signalling pathways including receptor tyrosine kinase, such as the EGFR, has been suggested to be able to limit the efficacy of GDP-KRAS targeting compounds in preclinical studies. These findings have been supported by clinical combination trials involving KRASG12C inhibitors such as Adagrasib and Sotorasib and anti-EGFR modalities. We demonstrate for the first time that combination with anti-EGFR antibodies (e.g., Cetuximab) potently enhances the response observed with BI 3706674 in settings of KRASG12V mutant pancreatic, colorectal, and lung cancer. The deeper response observed upon combination of BI 3706674 with Cetuximab across multiple xenograft models provides a strong rationale for the clinical investigation of this combination therapy. Moreover, we utilize an ex vivo organoid platform to rapidly identify novel drug combinations with BI 3706674 that can potentially translate to clinical trials. The KRASmulti inhibitor BI 3706674 is currently undergoing IND enabling studies. Single agent dose escalation will include patients with cancers harbouring KRASG12V mutations. Citation Format: David H Peng, Antonio Tedeschi, Lorenz Herdeis, Fabio Savarese, Francesca Rocchetti, Popow Johannes, Heinrich J Huber, Nicola Melillo, Jake Dickinson, Hitesh B Mistry, Birgit Wilding, Matthias Treu, Julian Fuchs, Joachim Broker, Tobias Wunberg, Fiorella Schischlik, Jesse Lipp, Vandhana Ramamoorthy, Joseph R Daniele, Scott Kopetz, Michael Kim, Don L Gibbons, Christopher P Vellano, Joseph R Marszalek, Timothy P Heffernan, Darryl McConnell, Mark Pearson, Norbert Kraut, Dorothea Rudolph. BI KRASmulti, a first-in-class, orally bioavailable and direct inhibitor of diverse oncogenic KRAS variants drives tumor regression in KRAS G12V-driven preclinical models [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr A087.

Preliminary Results from a Phase 1 Dose Escalation Study of FHD-286, a Novel BRG1/BRM (SMARCA4/SMARCA2) Inhibitor, Administered As an Oral Monotherapy in Patients with Advanced Hematologic Malignancies

The BRG/Brahma-associated factors (BAF) family of chromatin remodeling complexes (also referred to as the mSWI/SNF complex) regulates the chromatin landscape of the genome. Through its adenosine triphosphate (ATP)-dependent chromatin remodeling activity, BAF complexes regulate the accessibility of gene-control elements, allowing for the binding of transcription factors. Thus, BAF is a major regulator of lineage- and disease-specific transcriptional programs. FHD-286 is a first-in-class, orally administered compound that potently and selectively inhibits the ATPase components of the BAF complexes, SMARCA4 and SMARCA2 (also called BRG1 and BRM, respectively). In preclinical models, acute myeloid leukemia (AML) cell lines were highly sensitive to BAF inhibition. FHD-286-C-002 (NCT04891757) is a multicenter, open-label, Phase 1 dose escalation study designed to determine the safety, tolerability, dose-limiting toxicities (DLTs), and maximum tolerated dose and/or the recommended phase 2 dose(s), as well as to evaluate the preliminary clinical activity of FHD-286, in patients with advanced hematologic malignancies. Patients with relapsed or refractory (R/R) AML or myelodysplastic syndrome (MDS) failing all available standard therapies were eligible to receive FHD-286 doses ranging from 2.5 mg once daily (QD) to 10 mg QD on a continuous dosing regimen. Patients had regularly scheduled assessments to evaluate safety, pharmacokinetics (PK), pharmacodynamics, preliminary clinical activity, and exploratory biomarkers. As of 02 Aug 2022, 40 patients with a median age of 65.5 years (range 25 to 84) with R/R AML (36 patients) or MDS (4 patients) had received at least 1 dose of FHD-286. 67.5% of patients had received ≥3 prior lines of therapy for AML/MDS/other antecedent hematologic disorder, with 22.5% having received ≥5 prior lines. 32.5% of patients had prior hematopoietic stem cell transplant. 65% of patients had adverse risk genetics by 2017 ELN recommendations. 85% of patients experienced a treatment-related adverse event (TRAE) of any grade; the most common (≥20% of patients) were dry mouth (27.5%), increased blood bilirubin (22.5%), and alanine aminotransferase (ALT) increased and rash (20% each). 50% of patients experienced a Grade ≥3 TRAE, the most common of which was increased blood bilirubin (12.5%); stomatitis, ALT increased, differentiation syndrome (DS), and hypocalcemia occurred in 7.5% (each). 2 DLTs were reported: Grade 3 hyperbilirubinemia in 1 patient receiving 5 mg QD and Grade 3 muscular weakness in 1 patient receiving 10 mg QD. Treatment-related DS of any grade was investigator-reported in 4 patients (10%). An independent adjudication committee determined that the rate of suspected DS was 15% (6 patients). 16 patients (15 AML; 1 MDS) had a best overall response of stable disease. Markers of myeloid differentiation with neutrophil recovery and reductions in bone marrow and/or peripheral blasts have been observed in a subset of patients in the study who had a broad range of cytogenetic backgrounds, including patients with enhancer-driven leukemias such as MECOM and KMT2A. Preliminary PK analysis indicates that FHD-286 appears to have a long half-life, at a minimum of >24 hours, and that plasma concentrations of FHD-286 increase with increasing dose. Exploratory flow cytometry assessment of markers of differentiation, hematopoietic stem cell identity, and apoptosis suggested dose-dependent target engagement. Additionally, exploratory sequencing analysis on bone marrow blasts revealed comprehensive impacts on AML-specific expression pathways and stemness genes in response to FHD-286. An exposure-response analysis using the percentage of peripheral blasts showed a trend toward lower blast count with higher FHD-286 area-under-the-curve. Enrollment into the single-agent dose escalation phase of the study is complete. Based on nonclinical, translational, and single-agent clinical data, FHD-286 in combination with decitabine or low-dose cytarabine is being evaluated in the combination dose escalation phase of the study.

Abstract P4-01-35: A Phase 1 Study of the Oral CDK7 Inhibitor XL102 as a Single Agent and in Combination Therapy in Patients With Advanced Solid Tumors (QUARTZ-101): Initial Results From the Dose-Escalation Stage

Abstract Background: Cyclin-dependent kinase 7 (CDK7) plays a significant role in the cell cycle via activation of CDKs 1, 2, 4, and 6, and regulates transcription via phosphorylation of RNA polymerase II and the estrogen receptor. CDK7 overexpression has been reported in several tumor types, including hormone receptor-positive breast cancer (HR+ BC), triple-negative BC (TNBC), small-cell lung cancer, and epithelial ovarian cancer (EOC). In all major BC subtypes, CDK7 overexpression is associated with poor prognosis. XL102 is a potent, orally bioavailable, highly selective covalent CDK7 inhibitor. QUARTZ-101 is a first-in-human, open-label trial (NCT04726332) evaluating the safety, tolerability, and optimal dose of XL102 as a single agent and in combination regimens in patients with solid tumors, with expansion in subsequent tumor cohorts of advanced HR+ BC, TNBC, EOC, and metastatic castration-resistant prostate cancer (mCRPC). Presented here are initial results from the dose-escalation stage for single-agent XL102 (cohort A). Methods: In the single-agent dose-escalation stage, patients received XL102 orally at multiple dose levels (DLs) using a modified interval 3+3 design: once daily at 20 mg (DL A1), 40 mg (DL A2), 80 mg (DL A3), and 120 mg (DL A4); and twice daily at 40 mg (DL A5). Eligible patients had confirmed inoperable, locally advanced, metastatic, or recurrent solid tumors and ECOG performance status (PS) of 0 or 1; any CNS disease must have been adequately treated and stable for ≥4 weeks. Patients with previous exposure to XL102 or other selective CDK7 inhibitors were excluded, as were patients with uncontrolled, significant intercurrent or recent illness. Prior use of CDK4/6 inhibitors was allowed. The primary objective of dose escalation was to determine the maximum tolerated dose (MTD) and/or recommended dose (RD) of XL102; secondary objectives included safety and tolerability, pharmacokinetics (PK), and drug-drug interactions. Results: At data cutoff of May 13, 2022, twenty patients with various advanced solid tumors (100% stage IV) were enrolled in dose-escalation stage cohort A and treated with single-agent XL102 (DL A1 n=3; A2 n=3; A3 n=7; A4 n=4; A5 n=3). Median age was 67 (range 43–84) years, 85% were female, and 75% had an ECOG PS of 1. Six patients remained on XL102 including 2 treated for >6 months with stable disease, both had received prior CDK4/6 inhibitors (HR+BC and liposarcoma). There were no dose-limiting toxicities at any DL, and MTD/RD has not been determined. Treatment-emergent adverse events (TEAEs) occurred in 95% of patients, with 4 (20%) grade 3 and 0 grade 4 TEAEs; there were no grade 5 treatment-related AEs. Treatment discontinuations were mostly due to radiographic progression (n=8); longest treatment duration was 6.7+ months and ongoing. XL102 demonstrated rapid absorption with a Tmax of approximately 1–2 h and elimination half-life of 5– 8 h. Target occupancy was exposure-dependent and prolonged relative to XL102 PK, consistent with covalent binding to CDK7. Conclusions: Single-agent XL102 was well tolerated at the DLs tested. Updated data, as well as PK results, will be presented. Expansion cohorts in HR+BC, TNBC, EOC, and mCRPC will be initiated once a recommended dose for the expansion-cohort stage is determined. Citation Format: Amita Patnaik, Minal Barve, Manali Bhave, Vivek Subbiah, Drew Rasco, Aarohi Bhatt, Jing Li, Svetlana Andrianova, Geoffrey Shapiro. A Phase 1 Study of the Oral CDK7 Inhibitor XL102 as a Single Agent and in Combination Therapy in Patients With Advanced Solid Tumors (QUARTZ-101): Initial Results From the Dose-Escalation Stage [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-01-35.

Abstract A034: Bayesian adaptive design for phase I drug combination trials

Abstract Drug combination therapy is the most commonly used approach to overcome acquired resistance to cancer therapy. Designing phase I drug combination trials faces several challenges beyond the conventional single-agent dose escalation studies, e.g., two-dimensional dose space and partial order in toxicity. In this presentation, we will overview novel Bayesian adaptive designs for drug combination trials. In particularly, we will focus on model-assisted designs that are simply to implement, while yielding superior operating characteristics. Trial example and software will be provided to illustrate the application of the novel designs. Citation Format: Ying Yuan, Suyu Liu. Bayesian adaptive design for phase I drug combination trials [abstract]. In: Proceedings of the AACR Special Conference on the Evolutionary Dynamics in Carcinogenesis and Response to Therapy; 2022 Mar 14-17. Philadelphia (PA): AACR; Cancer Res 2022;82(10 Suppl):Abstract nr A034.

A Phase 2 Open-Label, Multicenter, Dose Optimization Clinical Study of the Safety, Tolerability, and Pharmacokinetic (PK) and Pharmacodynamic (PD) Profiles of Cfi-400945 As a Single Agent or in Combination with Azacitidine or Decitabine in Patients with Acute Myeloid Leukemia, Myelodysplastic Syndrome or Chronic Myelomonocytic Leukemia (TWT-202)

Background: CFI-400945 is a potent, selective, orally administered, first-in-class inhibitor of the serine/threonine kinase, Polo-like kinase 4 (PLK4). PLK4 is a highly conserved master upstream regulator of centriole duplication and is critical for maintenance of genomic integrity. Aberrant expression of PLK4 results in a number of effects including the centrosome amplification often seen in aneuploid cancers, pointing to a potentially causative role for PLK4 in genome instability and cancer progression. A Phase 1 study has been completed evaluating CFI-400945 as a monotherapy in solid tumors, showing a tolerable safety profile and promising signs of activity. Given acute myeloid leukemia (AML) is characterized by genomic instability, CFI-400945 has been evaluated in pre-clinical and clinical studies in AML. In pre-clinical studies, CFI-400945 showed potent activity towards leukemia cell lines and primary human samples in vitro, as well as marked efficacy in two subcutaneous models of leukemia. A prior Phase 1 trial in AML was initiated at the Princess Margaret Cancer Center (PMCC), and of six patients evaluable for response, two (33%) achieved complete remission (CR) at 96 mg and 128 mg, and 3 patients (50%) had stable disease (with one patient having a 78% reduction in marrow blast count) at 64 mg (2 patients) and 96 mg [re: Murphy et al, ASH 2020]. Responses were seen in patients with adverse cytogenetics. The optimal dosing of CFI-400945 and its potential role as a combination agent are not yet clinically defined.Study Design and Methods: The study (TWT-202) has 4 parts, Part 1A (1A): a single agent dose escalation portion, Part 1B (1B): a food effect portion once the MTD of 1A is determined, and combinations with azacitidine (2A), and decitabine (2B). TWT-202 uses an updated version of investigational product which is identical in formulation to the drug used in the PMCC study, but which may result in higher exposures at a given dose. This study will therefore refine the dose through escalation cohorts. For parts 1A and 1B, patients with relapsed and/or refractory AML, MDS, or CMML after >1 prior therapy will be included. Patients with MDS or CMML must have progressed or had a lack of response after at least 4 cycles of hypomethylating agents. For parts 2A and 2B, patients should have relapsed and/or refractory AML or untreated MDS or CMML. Untreated patients who decline or are ineligible for intensive therapy may be included. The study will use a standard 3 + 3 design. The maximum tolerated dose (MTD) will be defined as the dose level where the number of dose limiting toxicities (DLTs) is <1 out of 6 at highest dose level below the maximally administered dose. Pharmacokinetics (PK) and pharmacodynamic (PD) markers will be assessed.Results: As of June 21, 2021, 2 patients had been enrolled into the study, one of the patients (50%) received >3 prior therapies (including venetoclax). Neither patient had had stem cell transplant at study entry. Both patients had secondary AML (one with antecedent MDS with excess blasts and the other with CMML). Both patients received 32 mg of CFI-400945 for 21 days followed by a 7-day rest. Both patients completed cycle 1 and neither experienced a DLT. Both patients experienced a single serious treatment emergent adverse event (SAE) of febrile neutropenia each, with neither event considered related to CFI-400945. There were 13 Grade 3 or greater TEAE's, including anemia, thrombocytopenia (3 events each), febrile neutropenia (2 events), agitation, angioinvasive fungal sinusitis, acute kidney injury, hypotension and neutropenia (1 event each). None of the grade 3 or greater TEAE's were considered related to CFI-400945. Neither patient responded to therapy at 32 mg and both came off treatment after one cycle due to progressive disease. PK and PD studies are pending.Conclusion: CFI-400945 has been generally well tolerated and TWT-202 continues to enroll in the Part 1A and Part 1B monotherapy cohorts. Updated safety, efficacy, PK, and PD data for the study will be presented at the time of the meeting. DisclosuresBorthakur: University of Texas MD Anderson Cancer Center: Current Employment; ArgenX: Membership on an entity's Board of Directors or advisory committees; Protagonist: Consultancy; Astex: Research Funding; Ryvu: Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; GSK: Consultancy; Takeda: Membership on an entity's Board of Directors or advisory committees. Jonas: 47, AbbVie, Accelerated Medical Diagnostics, Amgen, AROG, Celgene, Daiichi Sankyo, F. Hoffmann-La Roche, Forma, Genentech/Roche, Gilead, GlycoMimetics, Hanmi, Immune-Onc, Incyte, Jazz, Loxo Oncology, Pfizer, Pharmacyclics, Sigma Tau, Treadwell: Research Funding; AbbVie: Other: Travel reimbursement; AbbVie, BMS, Genentech, GlycoMimetics, Jazz, Pfizer, Takeda, Treadwell: Consultancy. Roberts-Thomson: Treadwell Therapeutics: Current Employment. Michelson: Treadwell Therapeutics: Consultancy. Bray: Treadwell Therapeutics: Current Employment.

A phase I dose-escalation study to evaluate pharmacokinetics, safety and tolerability of ACT001 in patients with advanced glioma.

2044 Background: Management of advanced gliomas including glioblastoma multiforme (GBM) remains as an unmet medical need. Here we report our clinical experience with ACT001, or dimethylamino micheliolide, a synthesized derivative from parthenolide (a natural product of sesquiterpene lactone class), in Han Chinese patients with advanced glioma. Methods: Adult patients were enrolled in a 3+3 dose escalation phase 1 study with the following pre-defined ACT001 cohorts: 100mg, 200mg, 400mg, 600mg and 900mg, twice a day (BID). Pharmacokinetics and adverse events were evaluated during the study. Imaging studies were performed using RANO criteria to assess the therapeutic afficacy. Results: 16 patients with advanced glioma were enrolled in this single agent dose escalation study including 8 primary GBM, 4 astrocytoma (grade 2-3) and 4 other advanced glioma. The median age was 49 years (range: 31-70). Safety evaluation was performed in five cohorts and 13 of the 16 subjecst were evaluable for drug tolerability analysis. ACT001 was tolerated very well and no DLT or MTD was identified. Other than grade 1 adverse reactions (AE) in most cases and grade 2 AEs in other clinical findings, no drug-related grade 3 AE was noted. Pharmacokinetic analysis indicates that there was approximately linear correlate between the drug exposure (Cmax, AUC0-t and AUC0-inf) and study drug dosages evaluated. T1/2 is 4 hours with mean Cmax increased from approximate 300ng/ml to 5000ng/ml in a dose dependent manner with no significant dose accumulation during repeated dosing challenge. Post baseline MRI scans were performed in 11 out of 16 subjects. Among these 11 subjects, 1 GBM patient had a partial response (PR) at end of cycle 2 but had disease progressed at end of cycle 4; two non-GBM patients had a stable disease (SD) lasting for 5 or 6 cycles respectively before being taken off study due to disease pregression (PD) and other 8 patients had a PD. Of note, 9 out of these 11 subjects had stable or even improved clinical performance by the time they were taken off study due to PD. Five other subjects withdrew their consents or were taken off study due to clinical disease progression. Of note, subject S12 with diffusive astrocytoma was taken off study due to PD while still with a stable clinilcal performance and stereotactic biopsies targeting the progressed lesion didn’t reveal viable tumor tissues other than presence of macrophage/microglia. This subject was still alive 666 days after being taken off study. The mode of ACT001 actions is proposed to be at least partially related to its effects on tumor immune microenvironment. Conclusions: ACT001 was safe and tolerated well in patients. Clinical response was observed including a pathologic response in a subset of patients dosed at lower dose cohorts. iRANO criteria will be used in future studies based on its impacts on tumor immune microenvitonment. Clinical trial information: ChiCTR-OIC-17013604.

A Phase 2 Open-Label, Multicenter, Dose Optimization Clinical Study of the Safety, Tolerability, and Pharmacokinetic (PK) and Pharmacodynamic (PD) Profiles of Cfi-400945 As a Single Agent or in Combination with Azacitidine or Decitabine in Patients with Acute Myeloid Leukemia

A Phase 2 Open-Label, Multicenter, Dose Optimization Clinical Study of the Safety, Tolerability, and Pharmacokinetic (PK) and Pharmacodynamic (PD) Profiles of Cfi-400945 As a Single Agent or in Combination with Azacitidine or Decitabine in Patients with Acute Myeloid Leukemia

Abstract CT143: Phase I study of the combination of a RAF-MEK inhibitor CH5126766 and FAK inhibitor defactinib in an intermittent dosing schedule with expansions in KRAS mutant cancers

Abstract Background: Preclinical experiments in-vitro show MEK inhibitors can cause upregulation of p-FAK in KRASM cells. The combination of a MEK and FAK inhibitor could overcome this in-vitro and in-vivo. Methods: We are conducting an open label phase I dose escalation with expansion study (NCT03875820). Dose escalation evaluated a twice a week schedule (Mon/Thurs) CH5126766/VS-6766 (CH) 3 weeks out of 4 with a twice a day dosing schedule of defactinib (Def) administered 3 weeks out of 4. The dose levels explored were cohort 1 (CH 3.2 mg, 200 mg Def), cohort 2a (CH 4 mg Def 200 mg) and cohort 2b (CH 3.2 mg and Def 400 mg). Pharmacokinetic data were collected at cycle 1 d15 when both drugs were administered. In a subset of patients consenting to multiple biopsies, 3 biopsies were performed (baseline, after a single dose of CH run in and after 8-15 days of the combination therapy). At the recommended phase 2 dose (R2PD), expansion cohorts in patients with low grade ovarian cancer (LGSOC, n=20), KRASM non-small cell lung cancer (NSCLC, n=20) and KRASM colorectal cancer (CRC, n=10) will be treated. Results: Forty two patients have been treated on the trial so far. There were no dose limiting toxicities (DLTs) in the first 3 patients in cohort 1 and thus patients were recruited to cohort 2a and 2b. The cohort 2b dose level was deemed intolerable because of 2/3 patients experiencing DLTs of grade 2 rash not allowing dosing of 75% of the planned dose. No DLTs were seen in the first 6 patients treated on schedule 2a. However, given chronic grade 2 toxicities in patients on treatment &amp;gt; 6 months, the RP2D was deemed to be cohort 1. The most common side effects in the study were rash, CK elevation, AST elevation, hyperbilirubinemia and nausea, most of which were NCI CTC grade 1-2. All changes were reversible. The mean AUC of CH and Def at R2PD was 6179 ng*hr/ml and 2071 ng*hr/ml, respectively, which is in the range of what was seen in the single agent dose escalation studies. Sequential biopsies were obtained in 7 patients and 6/7 showed an increase in p-FAK following single agent CH which was reduced in 5/7 with combined CH and Def therapy. The response rate was 67% (4/6) or 50% (4/8) in KRASM LGSOC or all LGSOC patients treated to date, respectively. A range of KRASM were found in tumors of LGSOC patients who responded (G12V, G12A and G12D). Of the 4 patients with LGSOC who have responded to treatment, 3 have had a prior MEK inhibitor and are currently are on study for a median of 20.5 months (range 7-23 months). Expansion cohorts in LGSOC and KRASM NSCLC and CRC are ongoing and will be presented. Conclusion: We report a novel intermittent schedule of the combination of a RAF-MEK and FAK inhibitor with very promising clinical activity in patients with KRASM LGSOC including those who had been previously treated with a MEK inhibitor. Citation Format: Rajiv Shinde, Angelika Terbuch, Martin Little, Reece Caldwell, Roopa Kurup, Ruth Riisnaes, Mateus Crespo, Ruth Ruddle, Bora Gurel, Adam Stewart, Jenny King, Mona Parmar, Alison Turner, Florence Raynaud, Muneeb Mahmud, Christina Yap, Jonathan A. Pachter, Gordon B. Mills, Anna Minchom, Juanita Lopez, Susana N. Banerjee, Johann S. de Bono, Matthew Krebs, Udai Banerji. Phase I study of the combination of a RAF-MEK inhibitor CH5126766 and FAK inhibitor defactinib in an intermittent dosing schedule with expansions in KRAS mutant cancers [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 CT143.

A first-in-human phase I single-agent dose-escalation, food effect and dose expansion study of oral ONC206 in recurrent and rare primary central nervous system neoplasms.

TPS2576 Background: Blockade of the dopamine receptor D2 (DRD2) has emerged as a therapeutic target in neuro-oncology. ONC201, a first-generation imipridone that antagonizes DRD2, has demonstrated clinical activity in Diffuse Midline Gliomas, H3K27M-mutant (DMGs). Treatment options beyond surgical resection and radiation therapy are limited for most recurrent and rare primary CNS neoplasms. DRD2 blockade holds promise as a therapeutic target in multiple primary CNS cancers. ONC206 is a next generation imipridone and a chemical analog of ONC201 that possesses favorable drug properties such as oral bioavailability, robust stability, and blood-brain barrier penetrance. ONC206 exhibits enhanced allosteric inhibition of DRD2 and nanomolar affinity/potency as a DRD2 antagonist with complete antagonism and specificity for DRD2. ONC206 demonstrated broad spectrum anti-cancer efficacy in vitro across most solid tumor types tested in a panel of &gt; 1000 human cancer cell lines with nervous system tumors emerging as most responsive. In addition to its broad-spectrum activity in vitro, ONC206 efficacy has been demonstrated in xenograft mouse models. Methods: This is an open label, dose escalation, and food effect Phase I study of ONC206at the National Cancer Institute, Neuro-Oncology Branch. Adult patients 18 years and older with recurrent, primary CNS neoplasms will initially be accrued to the dose escalation portion of the study and evaluated for toxicity. Eligible diseases include recurrent glioblastoma, WHO Grade 2 and 3 infiltrating glial neoplasms, and rare primary CNS neoplasms in the NCI-CONNECT program: DMGs, ependymomas, medulloblastomas, and other rare CNS tumor types. The primary endpoint is to determine DLT during the first cycle (28 days). Dose escalation will proceed according to a standard 3+3 design. Both once weekly and more frequent dosing of ONC206 will be explored in the dose escalation scheme. After the MTD is established, food effect will be determined in a dedicated cohort using a balanced, single-dose, two-arm, two-period crossover design. Secondary endpoints will include objective response rate by RANO criteria, overall and progression-free survival, and disease control rate. Exploratory analysis of DRD2 and DRD5 expression, DRD2 dimerization, expression of MYC and N-MYC in tumor tissue in relation to clinical outcomes will also be performed.

Phase I monotherapy dose escalation of RGX-202, a first-in-class oral inhibitor of the SLC6a8/CKB pathway, in patients with advanced gastrointestinal (GI) solid tumors.

3504 Background: About 65% of advanced colorectal cancer (CRC) patients (pts) have creatine kinase B (CKB) expressing tumors. CKB expressing (CKB+) GI cancer cells import creatine via the creatine transporter SLC6a8 and utilize it to generate intracellular ATP. RGX-202, a small molecule inhibitor of SLC6a8, reduces intracellular creatine and ATP levels, leading to apoptosis. RGX-202 treatment triggers complete tumor regressions in multiple CKB+ preclinical models, including KRAS mutant CRC. Methods: RGX-202-001 is a phase I escalation/expansion study of RGX-202 +/- FOLFIRI in pts with advanced GI tumors. The primary safety objective during dose escalation is to identify the maximum tolerated dose (MTD), or the maximum tested dose at which multiple dose-limiting toxicities (DLTs) are not observed. The primary efficacy objective is to estimate the antitumor activity of RGX-202 by RECIST. Results: As of January 31, 2020, 17 pts have been treated in 4 single agent dose escalation cohorts: 600 mg BID (3 pts), 1200 mg BID (4 pts), 2400mg BID (5 pts) and 3600mg BID (5pts) given continuously. No DLTs were observed and an MTD was not reached. Treatment-related adverse events (TRAEs) occurring in &gt; 2 pts are shown in the Table. There were no Grade 4 TRAEs. At the highest dose, 2 of 3 CRC pts had prolonged disease control: a patient with a KRAS G13D mutant cancer had SD for 14 weeks; and a patient with KRAS G12V mutant (MSS) cancer had a confirmed PR ongoing at 30 weeks. Exposure to RGX-202 was greater than dose-proportional and the average AUC0-24 ranged from ~15,700 ng-hr/mL in cohort 1 to 241,097 ng-hr/mL in in Cohort 4. Serum and urine creatine levels, pharmacodynamic markers of SLC6a8 inhibition, correlated with systemic exposure to RGX-202. Conclusions: Among 17 patients treated with single agent therapy, no DLTs occurred; notably, exposures predicted to be sufficient to inhibit human tumor growth from preclinical models were achieved along with concomitant pharmacodynamic effects. These data, along with a durable PR observed in the highest dose cohort, support further development of RGX-202. Consequently, dose escalation in combination with FOLFIRI in patients with advanced GI cancers is underway with plans for expansion in CKB+ CRC pts. Clinical trial information: NCT03597581 . [Table: see text]

Abstract OT1-08-04: A first-in-human phase Ia dose escalation study of GDC-0077, a p110a-selective and mutant-degrading PI3K inhibitor, in patients with PIK3CA-mutant solid tumors

Abstract Background: Activating mutations in PIK3CA, encoding the p110α subunit of phosphatidylinositol 3-kinase (PI3K), are highly prevalent in breast cancer and solid tumor malignancies. GDC-0077 is a potent p110α-selective inhibitor with a novel mechanism of action that degrades mutant p110α and anti-tumor activity in PIK3CA-mutant breast cancer xenograft models as a single agent and in combination with anti-estrogens with or without a CDK4/6 inhibitor. An open-label, Phase I dose-escalation study of GDC-0077 monotherapy and GDC-0077 combined with endocrine therapies and palbociclib is underway in patients (pts) with locally advanced or metastatic PIK3CA-mutant solid tumors. Data from the completed single agent dose escalation portion of the trial are presented herein. Methods: This study (NCT03006172) assesses the safety (NCI-CTCAE v4), pharmacokinetics (PK), and preliminary anti-tumor activity (RECIST v1.1) of single agent GDC-0077 administered daily (QD) orally at 6, 9, or 12 mg in 28-day cycles until intolerable toxicity or disease progression. Tumor and ctDNA samples are profiled for relevant signaling and pharmacodynamic (PD) biomarkers. Results: As of the clinical cut-off date of 29 March 2019, 20 pts were enrolled in the single agent arm, all with hormone receptor-positive breast cancer, except for 1 pt with colorectal cancer. Nineteen patients had received ≥ 2 prior lines of therapy for metastatic disease. GDC-0077 MTD was established at 9 mg QD. DLTs occurred in 2 pts at 12 mg (1 Grade 4 hyperglycemia, 1 Grade 3 fatigue). Adverse events (AEs) resulted in dose reduction in 6 pts (30%). The most frequent treatment-related (TR)AEs in ≥ 3 pts (15%) included hyperglycemia (14 pts, 70%), diarrhea (8 pts, 40%), decreased appetite and vomiting (4 pts each, 20%), and alopecia, fatigue, nausea, and weight decreased (3 pts each, 15%). Grade ≥3 TRAEs were hyperglycemia (4 pts, 20%) and lymphopenia, fatigue, nausea, weight loss, and asthenia (1 pt, 5% each). Hyperglycemia was generally manageable with oral anti-hyperglycemic medications. Stomatitis (grouped term) occurred in 4 pts (20%, all Grade 1) and responded to topical corticosteroid treatment. Rash (grouped term) occurred in 3 pts (15%) (1 unrelated Grade 2, otherwise Grade 1). No colitis was reported. Mean half-life (t1/2) of GDC-0077 was 18 hours, with the maximum concentration (Cmax) achieved 2-8 hours after dosing. The preliminary PK profile of GDC-0077 showed low-moderate variability in Cmax and area under the concentration-time curve, and dose proportionality across the tested dose levels. Accumulation with QD dosing regimen was 1.6-2.4 fold. All pts discontinued from treatment due to disease progression (radiographic or clinical). Median GDC-0077 treatment duration was 5.3 months (range 1.1-17.6) and cumulative dose intensity was 97%. Overall, partial response (PR) was observed in 5 pts (25%, range 2-10 lines of prior metastatic therapy), with confirmed PR in 4 pts (20%). The clinical benefit rate was 45% (9 of 20 pts). Decreased PI3K pathway effector expression in paired tumor biopsies and decreased PIK3CA mutant allele frequency were observed over time in the majority of specimens. In addition, 18F-fluorodeoxyglucose-positron emission tomography scans at baseline and after 2 weeks of GDC-0077 showed metabolic responses at all dose levels evaluated. Conclusion: The single agent dose escalation study of the p110α-selective and mutant-degrading inhibitor GDC-0077 demonstrated linear PK, a manageable safety profile, PD modulation of the PI3K pathway, and promising preliminary anti-tumor activity. GDC-0077 at the recommended Phase II dose of 9 mg in combination with endocrine therapies with or without the CDK4/6 inhibitor palbociclib is being investigated in this Phase I study and presented separately. Citation Format: Dejan Juric, Kevin Kalinsky, Mafalda Oliveira, Andres Cervantes, Philippe Bedard, Ian Krop, Erika Hamilton, Peter Schmid, Andrea Varga, Nick Turner, Antoine Italiano, Cristina Saura, Valentina Gambardella, Zachary Veitch, Leslie Dickmann, Naoki Kotani, Jill Fredrickson, Amy Kapp, Katie Hutchinson, Stephanie Royer-Joo, Anjali Vaze, Jennifer Schutzman, Komal Jhaveri. A first-in-human phase Ia dose escalation study of GDC-0077, a p110a-selective and mutant-degrading PI3K inhibitor, in patients with PIK3CA-mutant solid tumors [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 OT1-08-04.

Designing and evaluating dose-escalation studies made easy: The MoDEsT web app.

Background/aims:Dose-escalation studies are essential in the early stages of developing novel treatments, when the aim is to find a safe dose for administration in humans. Despite their great importance, many dose-escalation studies use study designs based on heuristic algorithms with well-documented drawbacks. Bayesian decision procedures provide a design alternative that is conceptually simple and methodologically sound, but very rarely used in practice, at least in part due to their perceived statistical complexity. There are currently very few easily accessible software implementations that would facilitate their application.Methods:We have created MoDEsT, a free and easy-to-use web application for designing and conducting single-agent dose-escalation studies with a binary toxicity endpoint, where the objective is to estimate the maximum tolerated dose. MoDEsT uses a well-established Bayesian decision procedure based on logistic regression. The software has a user-friendly point-and-click interface, makes changes visible in real time, and automatically generates a range of graphs, tables, and reports. It is aimed at clinicians as well as statisticians with limited expertise in model-based dose-escalation designs, and does not require any statistical programming skills to evaluate the operating characteristics of, or implement, the Bayesian dose-escalation design.Results:MoDEsT comes in two parts: a ‘Design’ module to explore design options and simulate their operating characteristics, and a ‘Conduct’ module to guide the dose-finding process throughout the study. We illustrate the practical use of both modules with data from a real phase I study in terminal cancer.Conclusion:Enabling both methodologists and clinicians to understand and apply model-based study designs with ease is a key factor towards their routine use in early-phase studies. We hope that MoDEsT will enable incorporation of Bayesian decision procedures for dose escalation at the earliest stage of clinical trial design, thus increasing their use in early-phase trials.

1197P - A phase I study of Sym021, an anti-PD-1 antibody (Ab), alone and in combination with Sym022 (anti-LAG-3) or Sym023 (anti-TIM-3)

1197P - A phase I study of Sym021, an anti-PD-1 antibody (Ab), alone and in combination with Sym022 (anti-LAG-3) or Sym023 (anti-TIM-3)

Abstract C188: A phase 1 study of RXDX-105, an oral RET, BRAF and EGFR tyrosine kinase inhibitor, in patients with advanced or metastatic cancers

Abstract Background: RXDX-105 is a potent RET, BRAF and EGFR tyrosine kinase inhibitor (TKI) that exhibits high target affinity at low nanomolar concentrations. The RET proto-oncogene encodes a receptor tyrosine kinase for members of the glial cell line-derived neurotrophic factor (GDNF) family of extracellular signaling molecules. RET gain of function alterations are associated with the development of various types of human cancer, including non-small cell lung cancer (NSCLC). BRAF plays a key role in regulating the MEK/ERK signaling pathway, which affects cell division and differentiation. Acquired BRAF mutations can result in constitutive activation of this pathway, thereby fueling cancer growth. RXDX-105 is being developed as an oral therapy for patients with solid tumors that harbor RET or BRAF mutations or gene rearrangements. Methods: Adult pts with advanced solid tumors were enrolled in a Ph 1 single agent dose escalation study with a standard 3 + 3 design to determine the recommended Ph 2 dose. Oral RXDX-105 was given as a fixed dose on a continuous daily schedule. Tumor response was assessed at baseline and every 8 wks (RECIST v1.1). Treatment-emergent adverse events (AEs) were recorded according to NCI CTC v4.03. Pharmacokinetic (PK) assessment was also a study objective. Results: To date, 35 pts (17 M and 18 F) received RXDX-105 across 7 dose levels (20 to 275 mg QD). Median age was 60.5 years (range 27-81). The most frequent tumors (pts) were metastatic CRC (13), ovarian cancer (3), NSCLC (3), cholangiocarcinoma (3), and pancreatic cancer (3). Median number of cycles was 2 (range 1 to 23). 34 pts experienced AEs; 6 pts experienced treatment-related G3 AEs, including anemia, hypophosphatemia, fatigue, diarrhea, abdominal pain, rash and muscle weakness. 22 SAEs were reported from 9 pts, with none considered treatment-related. No treatment-related deaths occurred. The most common AEs were: fatigue (17 pts), vomiting (13 pts), abdominal pain (12 pts), nausea (11 pts), decreased appetite (10 pts), and rash (10 pts). At the time of this report, 3 pts have had DLTs; 1 pt at 200 mg with G2 hand and foot syndrome, 1 pt at 275 mg with G3 fatigue, and 1 pt at 275 mg with G3 asymptomatic hypophosphatemia. The protocol was amended to exclude hypophosphatemia as a DLT since it has been observed with approved TKIs and can be managed by supplementation. The PK data to date have demonstrated that RXDX-105 is absorbed with a median Tmax between 2 and 6 hrs at steady state. RXDX-105 plasma concentrations declined slowly after reaching Cmax with an average terminal half-life of 28 to 42 hrs across dose levels. There was a loss of dose proportionality at doses above 150 mg, possibly due to pH-dependent drug dissolution in the stomach. The impact of the fed state on exposure is being explored. 11 pts have been on treatment for ≥ 12 weeks. No objective responses have been observed; however, 1 pt with BRAF V600E-positive papillary thyroid cancer, previously treated with RAI, EBRT and multiple surgical resections, has been on study with stable disease for almost 2 years (23 cycles). Additionally, 2 heavily pre-treated pts with squamous NSCLC achieved clinical benefit with SD for &amp;gt; 6 months; 1 patient continues. Conclusions: To date, treatment with RXDX-105 demonstrates an acceptable safety profile. Improvements in bioavailability are being investigated. Dose escalation continues. Citation Format: Ding Wang, Manish Patel, Marwan Fakih, A. Craig Lockhart, Anthony J. Olszanski, Rupal Patel, Peter D. Brown, Jennifer W. Oliver, Pratik S. Multani. A phase 1 study of RXDX-105, an oral RET, BRAF and EGFR tyrosine kinase inhibitor, in patients with advanced or metastatic cancers. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr C188.

Dose-Finding Trial Designs for Combination Therapies in Oncology

Dose-Finding Trial Designs for Combination Therapies in Oncology

First-in-human phase I study of CetuGEX, a novel anti-EGFR monoclonal antibody (mAb) with optimized glycosylation and antibody dependent cellular cytotoxicity.

3008 Background: Epidermal growth factor receptor (EGFR) is a validated target in cancer. EGFR antagonists in clinical use do not exploit the full potential of this target. CetuGEX is an IgG1 mAb against EGFR. Fully human and optimized glycosylation lead to a 10- to 250-fold improvement of ADCC-mediated tumor cell killing in all FcγRIIIa allotypes and lack of immunogenic carbohydrate-chains, compared to cetuximab. Methods: Eligible patients with advanced solid tumors, progressing after standard treatment, were enrolled into this phase I, first-in-human, multicenter, single agent dose escalation trial. PK, PD and immunological parameters were assessed. Endpoints were safety and tolerability and secondarily pharmacokinetics, immunogenicity and anti-tumor activity. Results: 41 patients were treated on a q1w (8 dose levels from 12 to 1,370 mg flat dose), or q2w (990 mg flat) schedule. 25 pts had received at least 8 weekly doses (per protocol population [PP]).The most frequently observed drug-related AE were nausea (20%), vomiting (20%), hypertension (20%), almost all low grade and acneiform dermatitis (25%), only grade 1 or 2. Infusion-related reactions (IRR), virtually restricted to the first infusion, were associated with cytokine secretion: IL-6, IL-8, TNFα, IFNγ and IP-10 as marker of macrophage activation. Optimization of infusion scheme and premedication reduced IRRs in severity and frequency from 76% to 57% mainly of low grade. Blood NK cells were reduced as sign of redistribution. Activity was seen over all dose levels. One patient with NSCLC achieved a complete response. One patient with metastatic colorectal cancer had a partial response, another 2 patients with esophageal and gastric cancer without measurable disease at study entry had marked improvement of symptoms and normalization of tumor markers. Additional 15 pts had stable disease lasting from 8 weeks to over a year, including several minor responses, leading to a clinical benefit rate of 46% (19/41) in the overall and 76% (19/25) in the PP population. PK supports q1w and q2w dosing. Conclusions: CetuGEX shows clear signs of activity and acceptable toxicity. Phase II will soon be initiated. Clinical trial information: NCT01222637.