Abstract B79: Antitumor activity of lapatinib as a single agent and in combination with capecitabine in a HER2‐amplified human gastric tumor model

2521 Background: LVGN6051, a monoclonal antibody against CD137 (also known as 4-1BB or TNFRSF9) with an engineered Fc capable of selectively binding to the Fcγ receptor IIB, acts as a conditional CD137 agonist, resulting in immune activation optimally in tumor microenvironment ( Qi, Nat. Commun. 2019 ). In preclinical models, LVGN6051 demonstrated robust anti-tumor efficacy and safety as a single agent and in combination with anti-PD-1 antibodies. Therefore, we have initiated this first-in-human study of LVGN6051 alone or in combination with pembrolizumab for the treatment of advanced or metastatic malignancy. Methods: This study includes accelerated dose escalation monotherapy up to 2 mg/kg of LVGN6051, and traditional 3 + 3 design for higher doses of LVGN6051 alone or in combination with pembrolizumab. Then, this study will enroll patients with specific types of malignancies following Simon’s two-stage design. Both agents are administered once every 3 weeks. Primary objectives of this study were to define the safety profile and to establish the recommended phase 2 dose (RP2D) of LVGN6051 alone or in combination with pembrolizumab. Pharmacokinetics, immunogenicity, pharmacodynamics and clinical efficacy will be also evaluated. Results: At the cut-off date on January 18, 2021, 16 subjects have been enrolled into the monotherapy cohorts (n=12, no DLT observed up to 7 mg/kg), and the combination cohort (n=4, ongoing at LVGN6051 2 mg/kg and pembrolizumab 200 mg, one DLT observed). No treatment-related adverse event (TRAE) was observed in monotherapy. Treatment-emergent adverse events (TEAE) in combination included increased ALT/AST, thrombocytopenia, and fatigue. In the combination cohort, one patient with predominant hepatic metastases and history of intermittent grade 2 hepatic impairment experienced grade 3 increased ALT/AST (DLT) on cycle 1 day 15 that were resolved to her baseline without corticosteroids on cycle 1 day 18. TRAE included increased ALT/AST, thrombocytopenia, neutropenia, nausea and fatigue. Seven of 10 evaluable patients in the monotherapy cohorts demonstrated stable disease with the longest treatment being 8+ months. Tumor reductions by >10% were observed in melanoma and neuroendocrine tumor on monotherapy. One patient with metastatic head and neck squamous cell carcinoma who had progressed on an anti-PD-L1 based therapy showed an immune partial response (iPR) for 6+ months to the combination therapy. Conclusions: Preliminary evidence showed that LVGN6051 was well tolerated and tumor shrinkages were observed. While we continue assessing its safety profile, antitumor activity was observed in the LVGN6051 and pembrolizumab cohort. The favorable safety profile and preliminary antitumor activity warrant further evaluation in patients with advanced malignancies. Clinical trial information: NCT04130542.

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APTO-253 Induces KLF4 to Promote Potent in Vitro Pro-Apoptotic Activity in Hematologic Cancer Cell Lines and Antitumor Efficacy As a Single Agent and in Combination with Azacitidine in Animal Models of Acute Myelogenous Leukemia (AML)

Blood ◽

10.1182/blood.v124.21.4813.4813 ◽

2014 ◽

Vol 124 (21) ◽

pp. 4813-4813 ◽

Cited By ~ 1

Author(s):

William G Rice ◽

Avanish Vellanki ◽

Yoon Lee ◽

Jeff Lightfoot ◽

Robert Peralta ◽

...

Keyword(s):

Bone Marrow ◽

High Risk ◽

Animal Models ◽

Antitumor Activity ◽

Single Agent ◽

Xenograft Model ◽

Myelogenous Leukemia ◽

Acute Myelogenous ◽

Xenograft Models

Abstract APTO-253, a small molecule that mediates anticancer activity through induction of the Krüppel-like factor 4 (KLF4) tumor suppressor, is being developed clinically for the treatment of acute myelogenous leukemia (AML) and high risk myelodysplastic syndromes (MDS). APTO-253 was well tolerated in a Phase I study in patients with solid tumors using a dosing schedule of days 1, 2, 15, 16 of a 28 day cycle (2T-12B-2T-12B), but recent scientific observations guided APTO-253 toward AML and high risk MDS. Indeed, suppression of KLF4 was reported as a key driver in the leukemogenesis of AML and subsets of other hematologic diseases. The vast majority (~90%) of patients with AML aberrantly express the transcription factor CDX2 in human bone marrow stem and progenitor cells (HSPC) (Scholl et al., J Clin Invest. 2007, 117(4):1037-48). The CDX2 protein binds to CDX2 consensus sequences within the KLF4 promoter, thereby suppressing KLF4 expression in HSPC (Faber et al., J Clin Invest. 2013, 123(1):299-314). Based on these observations, the anticancer activity of APTO-253 was examined in AML and other hematological cancers. APTO-253 showed potent antiproliferative activity in vitro against a panel of blood cancer cell lines, with ηM IC50values in AML (6.9 - 305 ηM), acute lymphoblastic leukemia and chronic myeloid leukemia (39 – 250 ηM), non-Hodgkin’s lymphoma (11 – 190 ηM) and multiple myeloma (72 – 180 ηM). To explore in vivo efficacy, dose scheduling studies were initially conducted in the H226 xenograft model in mice. In the H226 model, APTO-253 showed improved antitumor activity when administered for two consecutive days followed by a five day break from dosing (2T-5B) each week, i.e. on days 1,2, 8,9, 15,16, 22,23, compared to the 2T-12B-2T-12B schedule. The 2T-5B schedule was used to evaluate antitumor activity of APTO-253 in several AML xenograft models in mice. In Kasumi-1 AML and KG-1 AML xenograft models, APTO-253 showed significant antitumor activity (p = 0.028 and p=0.0004, respectively) as a single agent when administered using the 2T-5B schedule each week for four weeks compared to control animals. Mice treated with APTO-253 had no overt toxicity based on clinical observations and body weight measurements. Mice bearing HL-60 AML xenograft tumors were treated with APTO-253 for one day or two consecutive days per week for three weeks, either as a single agent or combined with azacitidine, or with azacitidine alone twice per week (on days 1,4, 8, 11, 15 and 18). APTO-253 as a single agent inhibited growth of HL-60 tumors to approximately the same extent as azacitidine. Furthermore, both once weekly and twice weekly dosing of APTO-253 in combination with azacitidine resulted in significantly enhanced antitumor activity relative to either single agent alone (p = 0.0002 and p = 0.0006 for 1X and 2X weekly APTO-253 treatment, respectively, compared to control). Likewise, using a THP-1 AML xenograft model, APTO-253 administered as a single agent using the 2T-5B per week schedule showed significant efficacy, similar to that of azacitidine, while the combination of APTO-253 and azacitidine demonstrated greatly improved antitumor effects relative to either drug alone. APTO-253 was effective and well tolerated as a single agent or in combination with azacitidine in multiple AML xenograft models, plus APTO-253 does not cause bone marrow suppression in animal models or humans. Taken together, our results indicate that APTO-253 may serve as a targeted agent for single agent use and may provide enhanced efficacy to standard of care chemotherapeutics for AML and other hematological malignancies. Disclosures Rice: Lorus Therapeutics Inc.: Employment. Vellanki:Lorus Therapeutics Inc.: Employment. Lee:Lorus Therapeutics Inc.: Employment. Lightfoot:Lorus Therapeutics Inc.: Employment. Peralta:Lorus Therapeutics Inc.: Employment. Jamerlan:Lorus Therapeutics Inc.: Employment. Jin:Lorus Therapeutics Inc.: Employment. Lum:Lorus Therapeutics Inc.: Employment. Cheng:Lorus Therapeutics Inc.: Employment.

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„IN VITRO“ AND „IN VIVO“ ANTITUMOR ACTIVITY OF PLATINUM(II) COMPLEXES WITH MALONIC ACID ON BREAST AND COLORECTAL CARCINOMA CELL LINES

10.46793/iccbi21.293f ◽

2021 ◽

Author(s):

Andjela Franich ◽

◽

Milica Dimitrijević Stojanović ◽

Snežana Rajković ◽

Marina Jovanović ◽

...

Keyword(s):

Antitumor Activity ◽

Colorectal Carcinoma ◽

Cell Lines ◽

Tumor Model ◽

Carcinoma Cells ◽

Spectroscopic Techniques ◽

Murine Cell Line ◽

In Vivo Antitumor Activity

Four Pt(II) complexes of the general formula [Pt(L)(5,6-epoxy-1,10-phen)], where L is anion of malonic (mal, Pt1), 2-methylmalonic (Me-mal, Pt2), 2,2-dimethylmalonic (Me2-mal, Pt3) or 1,1- cyclobutanedicarboxylic (CBDCA, Pt4) acid while 5,6-epoxy-1,10-phen is bidentately coordinated 5,6-epoxy-5,6-dihydro-1,10-phenanthroline were synthesized and characterized by elemental microanalysis, IR, UV-Vis and NMR (1H and 13C) spectroscopic techniques. In vitro anticancer activity of novel platinum(II) complexes have been investigated on human and murine cancer cell lines, as well as normal murine cell line by MTT assay. The obtained results indicate that studied platinum(II) complexes exhibited strong cytotoxic activity against murine breast carcinoma cells (4T1), human (HCT116) and murine (CT26) colorectal carcinoma cells. Complex Pt3 display stronger selectivity toward carcinoma cells in comparison to other tested platinum(II) complexes exhibiting beneficial antitumor activity mainly via the induction of apoptosis, as well as inhibition of cell proliferation and migration. Further study showed that Pt3 complex also carry significant in vivo antitumor activity in orthotopical 4T1 tumor model without detected liver, kidney, lung, and heart toxicity. All results imply that these novel platinum(II) complexes have a good anti-tumor effect on breast and colorectal cancer in vivo and in vitro and the affinity to become possible candidates for treatment in anticancer therapy.

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A phase 1b, open-label, dose-escalation study to evaluate camidanlumab tesirine (Cami) as monotherapy in patients (pts) with advanced solid tumors.

Journal of Clinical Oncology ◽

10.1200/jco.2021.39.15_suppl.2556 ◽

2021 ◽

Vol 39 (15_suppl) ◽

pp. 2556-2556

Author(s):

Igor Puzanov ◽

Patricia LoRusso ◽

Kyriakos P. Papadopoulos ◽

Christopher T. Chen ◽

Yvan LeBruchec ◽

...

Keyword(s):

Antitumor Activity ◽

Solid Tumors ◽

Dose Escalation ◽

Stable Disease ◽

Single Agent ◽

Treatment Withdrawal ◽

Advanced Solid Tumors ◽

Open Label ◽

Phase 1B ◽

Grade 3

2556 Background: Depletion of tumor-infiltrating CD25+ regulatory T cells (Tregs), which inhibit tumor-specific immune responses, could contribute to tumor eradication. Cami (ADCT-301), an anti-CD25, pyrrolobenzodiazepine-based antibody-drug conjugate, targets CD25+ Tregs. A mouse surrogate has shown potent antitumor activity in solid tumor models. Here we report preliminary data from the monotherapy arm of a phase 1b trial of Cami in pts with selected advanced solid tumors. Methods: The monotherapy dose-escalation part of this open-label study enrolled pts (aged ≥18 years) with selected advanced solid tumors and no suitable existing therapy. The primary objective was to characterize safety and tolerability, and to identify the recommended phase 2 dose of Cami monotherapy. Secondary and exploratory objectives included evaluation of preliminary antitumor activity, pharmacokinetics (PK), pharmacodynamics (PD), and immunogenicity. Pts received Cami every 3 weeks (1 cycle) with dose escalation per a 3+3 design. Disease control rate (DCR) was assessed (complete and partial responses [CR, PR] and stable disease). Results: At data cut-off (Dec 17, 2020), 44 pts were enrolled, with primary tumor types (stage IVA/B: 27 pts; 61.4%) of colorectal (15 pts; 34.1%), pancreatic (14 pts; 31.8%), head and neck, ovarian/fallopian tube, and renal cell carcinoma (all 3 pts; 6.8%), non-small cell lung cancer (2 pts; 4.5%), gastric, esophageal/GEJ, melanoma, and triple-negative breast cancer (each 1 pt; 2.3%). Median (range) age was 60.5 (33–82) years; median (range) number of prior systemic therapies was 4 (1–9). Pts received a median (range) of 2 (1–6) Cami cycles at doses of 20–150 µg/kg. Median (range) treatment duration was 22 (1–178) days. No dose-limiting toxicities were reported. The maximum tolerated dose (MTD) was not reached. All-grade treatment-emergent adverse events (TEAEs) in ≥20% pts were nausea (18 pts; 40.9%), decreased appetite and fatigue (each 16 pts; 36.4%), constipation (13 pts; 29.5%), abdominal pain (11 pts; 25%), and rash (10 pts; 22.7%). The only Grade ≥3 TEAE in ≥10% pts was anemia (5 pts; 11.4%). Grade 3 autoimmune AEs (colitis, immune-mediated AE, systemic inflammatory response syndrome) and neurologic AEs (dysphagia and asthenia, but not GBS) were reported in 3 (6.8%) and 2 (4.5%) pts, respectively. 1 (2.3%) Cami-related TEAE led to treatment withdrawal; no Cami-related TEAEs were fatal. DCR was 25% (95% CI: 11.1, 34.7); 11/44 pts attained stable disease. No pts had CR or PR. Conclusions: Dose escalation of Cami monotherapy is complete. The safety profile is encouraging and MTD was not reached. PK/PD data will be presented. 150 µg/kg is the highest dose investigated for single-agent Cami and the highest to be investigated combined with pembrolizumab in selected advanced solid tumors in the current protocol. Funding: ADC Therapeutics SA NCT03621982. Clinical trial information: NCT03621982.

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Targeted Brain Tumor Therapy by Inhibiting the MDM2 Oncogene: In Vitro and In Vivo Antitumor Activity and Mechanism of Action

Cells ◽

10.3390/cells9071592 ◽

2020 ◽

Vol 9 (7) ◽

pp. 1592

Author(s):

Surendra R. Punganuru ◽

Viswanath Arutla ◽

Wei Zhao ◽

Mehrdad Rajaei ◽

Hemantkumar Deokar ◽

...

Keyword(s):

Brain Tumor ◽

Antitumor Activity ◽

Cell Lines ◽

Tumor Therapy ◽

Single Agent ◽

M Cell ◽

In Vivo Antitumor Activity ◽

The Brain

There is a desperate need for novel and efficacious chemotherapeutic strategies for human brain cancers. There are abundant molecular alterations along the p53 and MDM2 pathways in human glioma, which play critical roles in drug resistance. The present study was designed to evaluate the in vitro and in vivo antitumor activity of a novel brain-penetrating small molecule MDM2 degrader, termed SP-141. In a panel of nine human glioblastoma and medulloblastoma cell lines, SP-141, as a single agent, potently killed the brain tumor-derived cell lines with IC50 values ranging from 35.8 to 688.8 nM. Treatment with SP-141 resulted in diminished MDM2 and increased p53 and p21cip1 levels, G2/M cell cycle arrest, and marked apoptosis. In intracranial xenograft models of U87MG glioblastoma (wt p53) and DAOY medulloblastoma (mutant p53) expressing luciferase, treatment with SP-141 caused a significant 4- to 9-fold decrease in tumor growth in the absence of discernible toxicity. Further, combination treatment with a low dose of SP-141 (IC20) and temozolomide, a standard anti-glioma drug, led to synergistic cell killing (1.3- to 31-fold) in glioma cell lines, suggesting a novel means for overcoming temozolomide resistance. Considering that SP-141 can be taken up by the brain without the need for any special delivery, our results suggest that SP-141 should be further explored for the treatment of tumors of the central nervous system, regardless of the p53 status of the tumor.

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