Recommended Dose For Expansion Research Articles

First-in-human study of naporafenib (LXH254) with or without spartalizumab in adult patients with advanced solid tumors harboring MAPK signaling pathway alterations

BackgroundWe investigated naporafenib (LXH254), a pan-RAF kinase inhibitor, with or without spartalizumab, in patients with advanced solid tumors harboring MAPK pathway alterations. MethodsThis first-in-human phase 1 study had two dose-escalation arms: single-agent naporafenib (starting at 100 mg once-daily [QD]) and naporafenib (starting at the recommended dose/regimen)/spartalizumab (400 mg every 4 weeks). The naporafenib/spartalizumab dose-expansion part enrolled patients with KRAS-mutated non-small cell lung cancer (NSCLC) and NRAS-mutated melanoma. The primary objectives were to establish the maximum tolerated doses (MTD)/recommended doses for expansion (RDE) and evaluate tolerability and safety. ResultsA total of 142 patients were included in the naporafenib dose-escalation (n = 87), naporafenib/spartalizumab dose-escalation (n = 12) and naporafenib/spartalizumab dose-expansion (n = 43) arms. The MTD/RDE of naporafenib was 600 mg twice-daily (BID). In naporafenib escalation, five patients experienced 7 dose-limiting toxicities: decreased platelet count (1200 mg QD); neuralgia, maculopapular rash, pruritus (600 mg BID); increased blood bilirubin, hyponatremia, peripheral sensory neuropathy (800 mg BID). No DLTs occurred in the naporafenib/spartalizumab arm: the RDE was established at 400 mg BID. The most common treatment-related adverse events were rash and dermatitis acneiform (each 24.1%; naporafenib), nausea and pruritus (each 33.3%; naporafenib/spartalizumab; escalation) and rash (39.5%; naporafenib/spartalizumab; expansion). Naporafenib reduced DUSP6 expression in tumors. Two partial responses (PRs) occurred in naporafenib escalation, and 1 complete response and 3 PRs in the naporafenib/spartalizumab NRAS-mutated melanoma and KRAS-mutated NSCLC arms, respectively. ConclusionsNaporafenib, with or without spartalizumab, showed an acceptable safety profile, pharmacodynamic activity and limited antitumor activity. Additional naporafenib combination therapies are currently under investigation.

First-in-Human Dose-Escalation and -Expansion Trial with Sirpα Antibody BYON4228 in R/R B-Cell NHL

Introduction: Blocking of the immune checkpoint CD47-SIRPα promotes myeloid cell-mediated innate as well as adaptive immunity towards tumor cells. Antibodies in development are either directed against CD47 or SIRPα and in combination with tumor-targeting antibodies, checkpoint inhibitors, chemotherapeutics or other agents. The humanized SIRPα antibody BYON4228 (van Helden et al (2023) JITC 11: e006567) has been designed with three distinguishing characteristics compared to other CD47- or SIRPα-directed therapies which makes BYON4228 potentially best-in-class: 1.High specificity for SIRPα and no binding to SIRPγ on T cells which enables maximal contribution of T cells and therefore maximal anti-tumor immune response; 2.Silenced Fc backbone (IgG1-L234A/L235) which potentially results in reduced toxicity as confirmed in nonclinical studies showing no anemia or neutropenia in monkey; 3.Binding to both allelic forms of SIRPα (α 1 and α BIT) covering a broad patient population. Phase 1 clinical trial design: BYON4228.001 (NCT05737628) is the first-in-human clinical trial of BYON4228, in combination with rituximab, in relapsed or refractory (R/R) B-cell Non-Hodgkin's lymphoma (NHL). Part 1 (dose escalation) evaluates the safety, tolerability and Pharmacokinetics (PK) of, and receptor occupancy by BYON4228 to determine the maximum tolerated dose (MTD) or optimal biological dose (OBD) if the MTD is not reached, and recommended dose for expansion (RDE). A 28-day flat dose escalation schedule starting at 7 mg will be followed in a standard 3+3 design. Notably, only 1 cycle BYON4228 monotherapy will be given in each patient before combining with rituximab (375 mg/m 2 first cycle weekly administration; thereafter every 4 weeks for a total of 6 cycles). In part 2 (cohort expansion) BYON4228 + rituximab combination therapy will be given from cycle 1 onwards to further evaluate safety and efficacy in up to 24 additional diffuse large B cell lymphoma (DLBCL) patients and up to 24 patients with either marginal zone lymphoma (MZL) or follicular lymphoma (FL). This trial design of only 1 cycle monotherapy and swiftly moving into combination therapy not only allows to investigate PK and safety of BYON4228 but also efficacy of combination treatment with rituximab in a relevant therapeutic setting. Enrollment is ongoing in The Netherlands, United Kingdom, Italy and Spain since June 2023. Key inclusion criteria include, for part 1: B-cell NHL expressing CD20 by immunohistochemistry (IHC) or flow cytometry, R/R to at least 2 prior lines of therapy; for part 2, cohort A: Histologically confirmed DLBCL expressing CD20 R/R to front-line therapy, or second-line salvage regimens; for part 2, cohort B: Histologically confirmed MZL or FL (Grade 1-3a) expressing CD20, R/R to at least 2 prior lines of therapy. Autologous or allogeneic hematopoietic cell transplantation and autologous CAR-T cell therapy are allowed as prior lines. Key exclusion criteria include prior treatment with CD47- or SIRPα- targeting agents at any time; other anticancer therapy including investigational agents within 2 weeks or within at least 4 times the elimination half-life; Burkitt's lymphoma; history of active auto-immune disorders, active infections or uncontrolled systemic disease. Tumor response is determined according to Lugano and LYRIC criteria. An extensive biomarker program in the peripheral blood and bone marrow is included in the trial.

PHI-101 As a Potent Next-Generation FLT3 Inhibitor, Overcome Resistances in Previously Treated Patients with FLT3-ITD or TKD Acute Myeloid Leukemia: Results of a Phase Ia/Ib Clinical Trial

Background: The FLT3 receptor is mutated in about 30% of acute myeloid leukemia (AML) patients (pts) and has proven to be an attractive therapeutic target. The most prevalent alteration is internal tandem duplication (ITD) of the juxtamembrane domain, and several FLT3 inhibitors (e.g. gilteritinib, quizartinib, midostaurin) succeddfully target this mutation. However, patients frequently relapse due to resistance to these FLT3 inhibitors after initial clinical responses, often caused by the secondary mutations observed in the kinase domain (TKD) region. PHI-101, an orally bioavailable novel small molecule, is a next-generation FLT3 inhibitor that shows a potent anti-leukemic activity in primary AML samples harboring several FLT3-resistance mutations in preclinical studies. Global Phase I clinical trials with PHI-101 (NCT04842370) are currently underway in refractory or relapsed (R/R) AML pts. Study Design and Methods: The open-label, multicenter AML clinical trial consists of phase Ia, dose-escalation, and phase Ib, dose-expansion, utilizing oral PHI-101 tablets as a single-agent with R/R AML pts. If dose-escalation concludes with no dose-limiting toxicities (DLT), dose-expansion proceeds upon recommendation from the Safety Monitoring Committee (SMC). Response assessments with PHI-101 were reported according to 2017 ELN guidelines. The variant allelic frequency of mutations of FLT3 and other AML-related mutations was analyzed using NGS with bone marrow aspirates collected from pts before and after PHI-101 treatment. Blood samples were collected to evaluate pharmacokinetics (PK) and the plasma inhibitory assay (PIA) using FLT3-mutant cell lines. Together, these assessments were considered to determine the recommended dose for expansion (RDE) in phase Ib trials. Results: Phase Ia clinical trials of PHI-101 was designed to evaluate for safety and tolerability at five dose levels ranging from 40 mg to 200 mg. A total of 13 R/R AML pts were enrolled in the phase Ia and no DLTs were reported from daily doses of PHI-101 during the 28-day cycle. The target RDE at 160 mg was determined based on several considerations, including the PIA test achieving >85% inhibition of phosphor-FLT3, all available adverse events, PK data, and recommendation by the SMC. As of May 2023, with 6 pts enrolled in phase Ib, a total of 19 pts (5 FLT3-wild type (26.3%) and 14 FLT3 mutated (73.7%)), have been treated with PHI-101. Thirteen pts (68.4%) had more than 3 prior anti-leukemic treatments. Twelve of 13 pts (92%) assessed for the leukemic blast evaluation achieved clinical responses-4 pts with composite complete remissions [CRc, including complete remission with incomplete hematological recovery (CRi) and morphological leukemia free state (MLFS)] within 1 cycle of PHI-101 treatment. Ten pts were R/R following previous treatment with other FLT3 inhibitors (gilteritinib, quizartinib, midostaurin, or HM43239). 88 % of these pts achieved clinical responses including 3 CRc and 1 partial response (PR). Notably, all 5 R/R pts after gilteritinib treatment had clinical responses that included 2 with CRc. In addition, a patient with both FLT3-ITD and TKD (D835E and N676K) mutations who was resistant to 3 different FLT3 inhibitor treatments achieved PR and continued PHI-101 treatment for 6 cycles. Among pts who received 160 mg of PHI-101, 4 pts (57.1%) responded: 2 (28.6%) achieved CRi, 1(14.3%) achieved MLFS, and 1 (14.3%) achieved PR. Conclusion: In dose-escalating phase Ia clinical trials, PHI-101 was well tolerated at all dose levels with no DLTs. Phase Ib dose-expansion trials with 160 mg daily dosing are currently ongoing. PHI-101 has delivered CRcs at 120 mg and 160 mg. In this first-in-human, phase Ia/Ib trial of PHI-101, 92% of FLT3-wild or -mutated AML pts showed clinical responses even after having previously been treated with otherFLT3 inhibitors. More notably, 100% of pts who had relapsed after prior gilteritinib treatment showed clinical responses. The data from the clinical study of PHI-101to date demonstrates significant efficacy, particularly in R/R FLT3 mutant AML pts.

Phase I/Ib, open-label, multicenter, dose-escalation study of the anti-TGF-β monoclonal antibody, NIS793, in combination with spartalizumab in adult patients with advanced tumors

BackgroundNIS793 is a human IgG2 monoclonal antibody that binds to transforming growth factor beta (TGF-β). This first-in-human study investigated NIS793 plus spartalizumab treatment in patients with advanced solid tumors.MethodsPatients received...

First-in-human phase I/Ib study of NIZ985, a recombinant heterodimer of IL-15 and IL-15Rα, as a single agent and in combination with spartalizumab in patients with advanced and metastatic solid tumors

BackgroundPreclinically, interleukin-15 (IL-15) monotherapy promotes antitumor immune responses, which are enhanced when IL-15 is used in combination with immune checkpoint inhibitors (ICIs). This first-in-human study investigated NIZ985, a recombinant heterodimer...

1029P Dazostinag (TAK-676) alone and in combination with pembrolizumab (pembro) in patients (pts) with advanced or metastatic solid tumors: Preliminary safety, PK/PD, and anti-tumor activity in a phase I dose escalation study supporting a recommended dose for expansion (RDE)

1029P Dazostinag (TAK-676) alone and in combination with pembrolizumab (pembro) in patients (pts) with advanced or metastatic solid tumors: Preliminary safety, PK/PD, and anti-tumor activity in a phase I dose escalation study supporting a recommended dose for expansion (RDE)

A Phase 1/2, open label dose-escalation and expansion trial of NKT2152, an orally administered HIF2α inhibitor, to investigate safety, PK, PD and clinical activity in patients with advanced ccRCC

Abstract Background: Inactivation of the VHL gene leading to aberrant HIF2α activity is nearly universal in clear cell renal cell carcinoma (ccRCC). NKT2152 is a novel, potent, selective orally available HIF2α inhibitor optimized for enhanced PK exposure and sustained target inhibition which has demonstrated robust activity in both ccRCC cell line-derived and patient-derived xenograft RCC and other solid tumor models. This is a Phase 1/2 open label, multicenter, first in human study of NKT2152 in adults with advanced clear cell renal cell carcinoma (ccRCC) (NCT05119335). In Phase 1, up to ~60 patients will be enrolled according to a 3 + 3 design with backfill as permitted by the Safety Review Committee. The primary objective of phase 1 is to determine the recommended dose for expansion (RDE) based on the totality of clinical data. Phase 2 will enroll ~50 additional patients with the primary objective of determining investigator-assessed by RECIST v1.1. Key secondary objectives include safety, tolerability, PD effects, progression free survival, duration of response, and disease control rate. Exploratory objectives include evaluation of biomarkers predictive of tumor response. Adults who have advanced ccRCC without available standard therapy), ECOG PS 0-2, with measurable disease per RECIST 1.1 are eligible. Patients who have had prior HIF2a inhibitors, require supplemental oxygen, and with significant cardiac disease are excluded. Tumor assessments by CT or MRI are conducted every 8 weeks until 48 weeks, then every 12 weeks thereafter. Adverse events will be monitored and graded in severity using CTCAE v5.0. The Phase 1 study is currently actively accruing in the United States with Phase 2 dose expansion anticipated to start in Q3, 2023.

First-in-human phase 1 study of pimicotinib (ABSK021), a CSF-1R inhibitor, in patients with advanced solid tumors.

3100 Background: Colony-stimulating factor 1 (CSF-1) pathway is involved in the development of various types of cancer. Pimicotinib is an orally available, selective, potent small molecule CSF-1R inhibitor with significant pre-clinical anti-tumor activity. Here we present the results of the phase 1 trial. Methods: The escalation part employed a 3+3 design with a starting dose of 25 mg QD (28-day/ cycle) to determine the maximum tolerated dose (MTD) and the recommended dose for expansion (RDE). Additional pts with selected tumor types including pancreatic carcinoma, triple-negative breast cancer, lung cancer, and sarcoma were treated at RDE in the expansion part for further evaluation. Tenosynovial giant cell tumor (TGCT) cohorts were analyzed and reported separately. Results: As of December 31, 2022, 74 pts received at least one dose of pimicotinib at 25 mg (n=6), 50 mg (n=58), 75 mg (n=8), or 100 mg (n=2) QD. respectively. Median age was 59 y; 68.9% were female; 47.3% were white, 33.8% were Asian and 18.9% were African American. 74.3% were ECOG PS 1; 85.1% had metastasis; 67.6% had ≥3 lines of prior systemic anti-tumor therapies. Median duration of treatment was 49.5 days (range 4-377). Treatment-related adverse events (TRAEs), Grade ≥3 TRAEs, and serious TRAEs occurred in 74.3%, 21.6%, and 4.1% of pts, respectively. The most common TRAEs (≥20%) were serum enzyme elevations, including CPK, AST and LDH, which were all believed to be pimicotinib MOA related, with CPK increase (14.9%) being the only Grade ≥3 TRAE reported in ≥10% of pts. 3 pts (4.1%) reported serious TRAEs of ascites, blood bilirubin increase, and vaginal hemorrhage. After single and multiple dosing, pimicotinib plasma exposure increased slightly less than dose proportion. The rapid oral absorption (median tmax of 0.87 - 1.52 hrs) with moderate terminal t1/2 (mean t1/2 ranges: 43.6 - 63.5 hrs) suggested sustained drug exposure was achieved with a once daily dosing schedule. No dose adjustment was needed based on tested covariates including weight, age and race. Pimicotinib treatment led to a more than 85% reduction of non-classical monocytes (NCM) across all dose levels. Plasma CSF-1 levels were significantly increased from 25mg QD to 50mg QD and reached a plateau at 50mg QD, with ~40-fold maximal induction. Reduced CD163+ macrophages in skin and tumor tissues were seen at 50mg QD. All tested doses showed adequate inhibition of NCM, and CSF-1 change showed a positive correlation with plasma pimicotinib concentration. The MTD and RDE were determined as 75 mg QD and 50 mg QD. Conclusions: Tolerable safety profile and favorable PK/PD properties supported pimicotinib to be further evaluated in advanced solid tumors, including combinations. Clinical trial information: NCT04192344 .

First-in-human phase 1/2a study of a potent and novel CDK2-selective inhibitor PF-07104091 in patients (pts) with advanced solid tumors, enriched for CDK4/6 inhibitor resistant HR+/HER2- breast cancer.

3010 Background: PF-07104091 is a novel CDK2-selective inhibitor under investigation in pts with selected advanced or metastatic solid tumors. We present the first disclosure of data from the first-in-human, multicenter, phase 1 study of PF-07104091 monotherapy (NCT04553133). Methods: Pts with HR+/HER2- advanced/metastatic breast cancer (mBC) who received ≥ 2 lines of treatment for mBC including prior endocrine therapy (ET) + CDK4/6 inhibitors (CDK4/6i), and pts with other solid tumors, were included. Prior therapy with fulvestrant and chemotherapy was allowed for pts with mBC. PF-07104091 (75-500 mg) was given twice daily (BID) orally in 28-day cycles, following Bayesian design with overdose control, to determine the maximum tolerated dose (MTD)/recommended dose for expansion (RDE). Primary objective was to assess safety and tolerability. Secondary objectives included pharmacokinetics and preliminary anti-tumor activity. Results: At data cut off (Aug 23, 2022), 35 pts with advanced solid tumors (n = 29 mBC) with median age 62y (range 32-80y), median 4 lines of prior systemic therapy (range 1–12) and ECOG PS 0 (20% pts) or 1 were enrolled. Of 29 pts with mBC, all had prior CDK4/6i, 25 (86.2%) prior fulvestrant, and 21 (72.4%) prior chemotherapy. Treatment-emergent adverse events (TEAEs) were observed in 34 pts (97.1%; 20 [57.1%] grade [G] ≥ 3). The most frequent TEAEs (all G≤3) were nausea (77.1%; 14.3% G3), diarrhea (48.6%; 8.6% G3), vomiting (48.6%; 2.9% G3), fatigue (45.7%; 20.0% G3) and anemia (45.7%; 8.6% G3). Dose-limiting toxicity occurred in 5 pts: 1 pt (G3 fatigue) at 300 mg BID; 2 pts (1 G3 nausea and G3 anorexia, 1 G3 nausea) at 375 mg BID, and 2 pts (1 G3 fatigue and 1 G3 diarrhea) at 500 mg BID. Steady-state PF-07104091 plasma exposures increased proportionally with dose. A trend of early decrease in ctDNA was observed. Further pharmacodynamic studies are ongoing. PF-07104091 300 mg BID was identified as the MTD and selected as the monotherapy RDE. Among 16 response evaluable mBC pts (all prior CDK4/6i+ET) with measurable disease at baseline, confirmed RECIST v1.1 partial responses were observed in 3 (18.8 %) pts (2 pts with duration of response > 6 months and 1 ongoing at data cut off), and stable disease in 6 (37.5%) pts. Disease control rate was 61.5% in mBC pts (response evaluable set, 95% CI: 40.6, 79.8). Conclusions: Treatment with PF-07104091 monotherapy was generally well tolerated and showed antitumor activity in heavily pretreated HR+ HER2- mBC pts who progressed on prior CDK4/6i. Dose expansions of PF-07104091 are ongoing as monotherapy in pts with ovarian cancer and in combination with fulvestrant in pts with breast cancer. Clinical trial information: NCT04553133 .

A phase Ia/Ib, dose-escalation/expansion study of the MDM2–p53 antagonist BI 907828 in patients (pts) with solid tumors: Safety and efficacy in patients with dedifferentiated liposarcoma (DDLPS).

11554 Background: Inactivation of p53 is a key mechanism which promotes tumor survival and proliferation. p53 inactivation can be due to mutations in TP53 or downregulation of wild-type (wt) p53 by the key negative regulator mouse double-minute 2 (MDM2). BI 907828 is a highly potent MDM2–p53 antagonist which has demonstrated preclinical antitumor activity, particularly in TP53-wt MDM2-amplified DDLPS models. In this phase I study (NCT03449381), BI 907828 monotherapy is being evaluated in pts with advanced solid tumors, including DDLPS. During dose escalation (phase Ia), BI 907828 had a manageable safety profile and the selected recommended dose for expansion (RDE) was 45 mg q3w. Here we report safety data in all pts who received the RDE of 45 mg q3w and present efficacy data in the subgroup of pts with DDLPS. Methods: In Phase Ia, pts received one of two BI 907828 dosing schedules: Arm A, day 1 of 21-day cycles (q3w); Arm B, days 1 and 8 of 28-day cycles. During Phase Ib (dose expansion), pts were enrolled to Cohort 1 ( TP53wt, MDM2-amplified sarcoma) or Cohort 2 (other TP53wt, MDM2-amplified solid tumors). Here we focus on Cohort 1 (received BI 907828 45 mg q3w). The primary endpoint (phase Ib) was progression-free survival (PFS). Secondary endpoints/objectives included overall response rate (ORR) and grade ≥3 treatment-related AEs (TRAEs). Results: As of December 22, 2022, a total of 137 pts had been enrolled; 72 (52.6%) were male, 77 (56.2%)/59 (43.1%) had ECOG PS 0/1, and the median number of prior systemic therapies was 2 (range, 0–11). In the 73 pts who received the RDE of 45 mg q3w, the most common any-grade TRAEs were nausea (74.0%) and fatigue (61.6%). 33 (45.2%) pts had grade ≥3 TRAEs; the most common were thrombocytopenia (23.3%), neutropenia (21.9%), anemia (11.0%), and leukopenia (11.0%). 22 (30.1%) pts had TRAEs leading to dose reductions and 6 (8.2%) had TRAEs leading to treatment discontinuation. 20 pts (27.4%) had serious AEs; the most common were nausea, pulmonary embolism (each 4.1%), sepsis, small intestine obstruction, vomiting, thrombocytopenia, and pyrexia (each 2.7%). 50/73 pts who received 45 mg q3w had advanced DDLPS; all had MDM2-amplified disease. Of the 42 evaluable DDLPS pts, 8 achieved a confirmed PR (ORR 19.0%; locally assessed) and a further 29 achieved a best response of stable disease (including 2 with unconfirmed PR), giving a disease control rate of 88.1%. Preliminary median PFS was 8.1 months. Conclusions: BI 907828 demonstrated a manageable safety profile overall and encouraging preliminary efficacy was seen in pts with advanced MDM2-amplified DDLPS; Phase Ib is ongoing. BI 907828 is also being evaluated versus doxorubicin as first-line treatment for pts with advanced DDLPS in the ongoing Phase II/III Brightline-1 study (NCT05218499), for which the FDA has granted a Fast Track Designation. Clinical trial information: NCT03449381 .

Abstract CT272: Pharmacodynamic and immunophenotyping analyses of ATR inhibitor M1774 in a Phase I study in patients with solid tumors (DDRiver Solid Tumors 301)

Abstract Background: Ataxia telangiectasia and Rad3-related (ATR) protein kinase plays a critical role in the DNA damage response. M1774, a potent, selective, orally administered ATR inhibitor with antitumor activity in preclinical models, was evaluated in Part A1 of an open-label, single-arm study (NCT04170153) for safety, tolerability, maximum tolerated dose, pharmacokinetics (PK) and pharmacodynamics (PD). M1774 monotherapy in patients with advanced solid tumors was well-tolerated and the totality of evidence, including quantitative model-based analyses, suggested the recommended dose for expansion (RDE) as 180 mg QD 2 weeks on/1 week off.1 Here, we report findings of the M1774 PD and immunophenotyping analyses. Methods: M1774 PD was explored by assessing phosphorylation by ATR of CHK1 (p-CHK1) in tumor and of H2AX (γ-H2AX) in serial blood samples, stimulated ex vivo with the radiomimetic 4-Nitroquinoline N-oxide or Dimethyl sulfoxide as control. A flow cytometry quantitative assay was used to measure γ-H2AX in the CD45+ lymphocytes fraction. The effect of M1774 on the immunophenotype was explored by flow cytometry. Blood samples were collected at baseline, 3 and 24 hours after first M1774 administration on day 1 of cycle 1 for the γ-H2AX analysis, and on Days 1 and 15 of Cycles 1 and 2 before treatment for immunophenotyping. Results: Preclinical tumor tissue-blood bridging PD analyses in a mouse model demonstrated that the inhibition of γ-H2AX in lymphocytes highly correlated with inhibition of p-CHK1 in tumor. Clinical data of γ-H2AX levels and immunophenotyping were generated for the blood samples collected from the 55 participants of Part A1 of the study. Exploratory PK-PD analysis using γ-H2AX levels 3 h post-dose on day 1 across the doses predicted target inhibition >80% for doses ≥130 mg, suggesting target engagement. The levels of ɣ-H2AX at 24 h after first dose intake were variable and mean levels rebounded to baseline value. M1774 treatment did not cause any significant and consistent change in the levels of all explored immune cell subsets at the tested dose levels, including myeloid-derived suppressor cells, T and B lymphocytes, monocytes, and natural killer cells. Conclusions: PD analyses showed that M1774 efficiently inhibited ATR at the RDE without impacting the immunophenotype. 1TA Yap, et al. Ann Oncol. 2022; 33(suppl_7): S197-S224. Citation Format: Ruth Plummer, Anthony W. Tolcher, Timothy A. Yap, Giuseppe Sessa, Jatinder K. Mukker, Annick Seithel-Keuth, Christine Hicking, Zoltan Szucs, Ioannis Gounaris, Giuseppe Locatelli, Johann S. de Bono. Pharmacodynamic and immunophenotyping analyses of ATR inhibitor M1774 in a Phase I study in patients with solid tumors (DDRiver Solid Tumors 301) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT272.

Abstract CT185: First in human dose-escalation trial with the c-MET targeting antibody-drug conjugate BYON3521

Abstract Background: BYON3521 is a novel c-MET targeting antibody-drug conjugate (ADC) with a cleavable linker-duocarmycin (vc-seco-DUBA) payload that causes irreversible alkylation of DNA in tumor cells. BYON3521 has demonstrated potent and selective killing of c-MET expressing tumor cells in preclinical models, even at low c-MET expression levels. In addition, in vitro studies showed that the active toxin can passively permeate the cell membrane and kill neighboring, c-MET negative cells as a bystander effect. Methods: Patients with previously treated progressive locally advanced or metastatic solid tumors, c-MET positive membrane staining by immunohistochemistry and/or MET-amplified by dual in situ hybridization and/or known activating MET-mutation (excluding exon14m), ECOG performance status 0-1 and adequate organ function are eligible for the dose-escalation part of this first-in-human trial (ClinicalTrials.gov identifier: NCT05323045). An adaptive approach using the Continual Reassessment Method of Neuenschwander (N-CRM model) is used to evaluate the safety of BYON3521 and to determine the maximum tolerated dose (MTD) and recommended dose for expansion (RDE). BYON3521 is administered intravenously every three weeks until tumor progression or unacceptable toxicity. Results: Up to 01 January 2023, 8 patients (1F, 7M, median age 61 yrs) were enrolled. Tumor types were: 4 colorectal cancer, 1 NSCLC, 1 renal cell carcinoma, 1 esophageal cancer and 1 pancreatic cancer. One patient received 0.8 mg/kg, three patients each 1.6 and 3.2 mg/kg and one patient received 4.8 mg/kg. So far, no grade 3 or 4 related adverse events and no dose-limiting toxicities (DLTs) occurred. Most commonly observed related AEs were decreased appetite/weight, fatigue, abdominal pain, back pain, vomiting and chills. Typical ADC associated AEs as keratitis and pneumonitis have not been observed so far. Stable disease was the best response observed in 2 patients at a dose of 3.2 mg/kg. Human PK was in line with predicted preclinical in vivo PK. Conclusions: To date, BYON3521 is well-tolerated with no DLTs at the investigated dose levels. Patient enrollment is ongoing and updated safety, efficacy and pharmacokinetic data will be presented. After the dose-escalation phase the trial will continue with expanded cohorts of patients with specific c-MET expressing cancer types. Citation Format: N. Kotecki, C.M.L. van Herpen, C. Curigliano, M. Hendriks, T C. Vermaas, L. Corrigan, C. Belli, C. Jungels, I.M.E. Desar, N.P. Koper, J.H.M. Schellens, U. Banerji. First in human dose-escalation trial with the c-MET targeting antibody-drug conjugate BYON3521 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT185.

Abstract CT195: Interim safety results from SEPION/AIO-PAK-0118: A multicenter, Phase I/II study of sequential epigenetic and immune targeting in combination with nab-paclitaxel/gemcitabine in patients with advanced pancreatic ductal adenocarcinoma

Abstract Background: Pancreatic ductal adenocarcinoma (PDAC) remains a hard-to-treat cancer entity with limited therapeutic options. We aim to enhance the anti-tumor and pro-immunogenic effect of standard-of-care nab-paclitaxel/gemcitabine (GnP) by concomitant epigenetic targeting followed by immune-modulating maintenance therapy in patients (pts) with treatment-naive metastatic PDAC. This phase 1/2, open-label, multicenter, dose-escalation/dose-expansion study evaluates the safety and tolerability of azacitidine (AZA) and romidepsin (ROM) in combination with GnP and the potential of immune-modulating consolidation with durvalumab and lenalidomide after three cycles of either GnP or GnP plus epigenetic targeting. Here we report interim results of the dose escalation. Methods: In part 1A, dose escalation of three regimen ROM/GnP (arm A), AZA/GnP (arm B) and ROM/AZA/GnP (arm C) for determination of the recommended dose for expansion (RDE) is performed with a 3 + 3 dose escalation scheme using fixed dose levels. For dose expansion (part 1B), one of the treatment arms (Arm C over B over A) is continued using a Simon two-stage design to a maximum of 35 patients. The efficacy of the sequential programmed death-ligand (PD-L)1 blockade in combination with low-dose lenalidomide is evaluated in study part 2 (consolidation part) for pts with controlled disease (DCR) after 3 cycles of part 1 therapy. Evaluation of the consolidation concept in part 2 requires a sufficient DCR based on the statistical considerations. Thus, in addition to pts in part 1A and 1B, pts treated with GnP alone are additionally recruited (standard arm), so that at least 41 pts with controlled disease after 3 cycles of therapy are available for part 2. Key eligibility includes metastatic PDAC (stage IV), ECOG 0-1 and no prior chemotherapy or radiotherapy therapy for stage IV PDAC. Primary objectives include safety and tolerability of AZA and/or ROM in combination with GnP followed by sequential immune targeting with PD-L1 blockade in combination with low-dose lenalidomide. Results: In October 2022, 76 pts were enrolled, of which 67 pts were treated with at least one dose of study medication. The median age in the treated population was 62.8 years (range: 33 - 83), 32 (47.8 %) were female, 80.6 %/13.4 % were included with ECOG 0/1. In part 1A, an RDE of 2mg/m² for ROM (N=3, dose level L-1) and 30mg/m² for AZA (N=6, dose level L1) was established, respectively. The combined administration of AZA (30 mg/m²), ROM (2 mg/m²) and GnP (arm C) led to severe DLTs, namely neutropenia, non-hematologic toxicities (> grade2) and ROM related non-hematologic toxicities (≥ grade2) in all three patients. Given the best safety profile, Arm B was chosen for the expansion part 1B. Conclusions: ROM in combination with GnP showed considerable toxicity at dose level L1 as did the combination of ROM (dose level L-1) and AZA (dose level L1) with GnP. The combination of 30 mg/m2 AZA with GnP was feasible and chosen for further expansion. Dose expansion (part 1B) and sequential immunotherapy consolidation (part 2) are ongoing. Clinical trial information: NCT04257448. Research Sponsor: GWT-TUD GmbH. Citation Format: Jens T. Siveke, Marianne Sinn, Stefan Boeck, Gabriele Siegler, Thomas Seufferlein, Joerg Trojan, Dirk Waldschmidt, Alexander Koenig, Dorothea Schipp, Ines Winkler, Sven Thorsten Liffers, Volker Kunzmann. Interim safety results from SEPION/AIO-PAK-0118: A multicenter, Phase I/II study of sequential epigenetic and immune targeting in combination with nab-paclitaxel/gemcitabine in patients with advanced pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT195.

Abstract CT257: First-in-human phase 1 studies of PTPN2/1 inhibitors ABBV-CLS-484 and ABBV-CLS-579 in locally advanced or metastatic tumors

Abstract Background: Protein tyrosine phosphatase non-receptor type 2 and type 1 (PTPN2/1) antagonists inhibit PTPN2/1-mediated negative regulation of immune response pathways. They may promote antitumor activity by increasing function of immune cells such as T cells and dendritic cells, inducing cytokine production, increasing antigen presentation, and amplifying interferon gamma-mediated tumor growth arrest. ABBV-CLS-484 and ABBV-CLS-579 are potent, orally bioavailable, first-in-class PTPN2/1 inhibitors that showed promising antitumor activity and were well tolerated in preclinical models. Preclinical data also indicated that PTPN2/1 inhibitors have improved efficacy when combined with PD-1-targeting agents (eg, pembrolizumab) or vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitors (TKIs) in multiple tumor models. Here, we describe 2 first-in-human trials of ABBV-CLS-484 or ABBV-CLS-579 as monotherapy and in combination with pembrolizumab or VEGFR TKI in patients with locally advanced/metastatic tumors. Methods: These phase 1, open-label, multicenter, non-randomized trials (ABBV-CLS-484: NCT04777994; ABBV-CLS-579: NCT04417465) comprise dose-escalation (ESC) and dose-expansion (EXP) phases. ESC is guided by a Bayesian optimal interval design based on dose-limiting toxicities. ESC data are used to inform evaluation of EXP cohorts in select tumor types including relapsed/refractory (R/R) head and neck squamous cell carcinoma, R/R non-small cell lung cancer, advanced renal cell carcinoma, and microsatellite instability-high tumors. In both ESC and EXP phases, the study drug (ABBV-CLS-484 or ABBV-CLS-579) is administered orally either alone or in combination with pembrolizumab (200 mg intravenously once every 3 weeks) and is slated to also be administered in combination with a VEGFR TKI. Eligible patients have locally advanced/metastatic tumors for which no effective standard therapy exists (or has failed), and Eastern Cooperative Oncology Group performance status ≤2. Patients (≥18 years) must have received ≥1 prior systemic anticancer therapy for the indication being considered, have relapsed or be refractory to ≥1 prior anti-PD-1/PD-L1 therapy (EXP monotherapy and pembrolizumab combination), or have relapsed after ≤1 (ABBV-CLS-484) or ≥1 (ABBV-CLS-579) prior VEGFR TKI therapy (EXP VEGFR TKI combination). Primary objectives are to assess safety, tolerability, pharmacokinetics, and to determine the recommended expansion dose and/or maximum tolerated dose of ABBV-CLS-484 or ABBV-CLS-579, both as monotherapy and in combination. Evaluation of objective response rate (RECIST v1.1) is a primary objective in EXP phase and a secondary objective in ESC phase. Both studies are active, and as of 30 Nov 2022, 30 (ABBV-CLS-484) and 45 (ABBV-CLS-579) patients had been enrolled in ESC phase. Citation Format: Patricia M. LoRusso, Emiliano Calvo Aller, Noboru Yamamoto, Chia-Chi Lin, Thaddeus Beck, David Sommerhalder, Do-Youn Oh, John D. Powderly, Talia Golan, Linu Sara Abraham, Joel S. Hayflick, Tamar Uziel, Priya Brunsdon, Wijith Munasinghe, Marcia Paddock, Cathleen Brdlik Hartman, Jonathan Powell, Bruno Medeiros, Martha R. Neagu, Benedito A. Carneiro. First-in-human phase 1 studies of PTPN2/1 inhibitors ABBV-CLS-484 and ABBV-CLS-579 in locally advanced or metastatic tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT257.

A multi-center, open-label, randomized dose expansion study of PF-06821497, a potent and selective inhibitor of enhancer of zeste homolog 2 (EZH2), in patients with metastatic castration-resistant prostate cancer (mCRPC).

TPS282 Background: Enhancer of zeste homolog 2 (EZH2) encodes the histone methyltransferase component of the polycomb repressive complex-2, inducing transcriptional silencing of target genes, and is altered in cancers such as follicular lymphoma (FL), small cell lung cancer (SCLC), and metastatic castration-resistant prostate cancer (mCRPC). We evaluated the pharmacokinetics (PK), safety, and antitumor activity of PF-06821497, a potent and selective inhibitor of EZH2, in an ongoing phase I trial (NCT03460977 ) in patients (pts) with SCLC, CRPC, and FL as monotherapy and in combination with standard of care therapies. For pts with CRPC, the PF-06821497 recommended dose for expansion (RDE) is 1250 mg BID, in combination with enzalutamide plus androgen deprivation therapy (E). Part 2B of this trial further explores outcomes for pts dosed with PF-06821497 and E compared with E monotherapy. Methods: Part 2B compares the safety and efficacy of twice-daily PF-06821497 in combination with E (160 mg daily) (treatment arm) versus E monotherapy (control arm) administered continuously in patients with mCRPC previously treated with abiraterone. At trial entry, all pts will have evidence of prostate cancer progression per the modified Prostate Cancer Working Group 3 Criteria. Prior treatment with E is not allowed. Approximately 80 participants will be randomized in a 1:1 fashion into two arms, in US, Spain, and other countries. Approximately 40 participants are required in each arm to have 80% power in the study in order to detect a hazard ratio of 0.5 (E plus PF-06821497: E alone). Patients randomized to E alone have the option to add PF-06821497 to their regimen upon confirmed radiographic disease progression. The primary objectives are to confirm the safety and tolerability of PF-06821497 in combination with E in pts with mCRPC, and to assess the effect of PF-06821497 in combination with E versus E monotherapy on radiographic progression free survival. Secondary objectives include further evaluation of anti-tumor activity of PF-06821497, and assessment of single and multiple dose PK when given in combination with E. The impact of PF-06821497 in combination with E and of E alone in men with mCRPC on patient reported outcomes will also be assessed. Clinical trial information: NCT03460977 .

A phase 1, open-label, dose escalation and expansion, multicenter study of claudin 18.2-targeted chimeric antigen receptor T-cells in patients with unresectable, locally advanced, or metastatic gastric, gastroesophageal junction, esophageal, or pancreatic adenocarcinoma.

TPS480 Background: Locally advanced and metastatic gastric, esophageal, gastroesophageal junction, and pancreatic adenocarcinomas (GC, EC, GEJC, and PC) have poor overall survival, and more effective therapies are needed. Claudin 18.2 (CLDN18.2), a tight junction protein, is commonly expressed in these cancers. Monoclonal antibody and CAR-T cell therapies targeting CLDN18.2 have shown promising antitumor activity (Türeci O et al, 2019; Qi C et al, 2022). This study aims to assess the safety and preliminary efficacy of a CLDN18.2 targeted CAR-T, LB1908, in subjects with GC, EC, GEJC, and PC. Methods: This is a phase 1, open-label, multicenter, dose-escalation and expansion study of LB1908 that aims to identify the recommended phase 2 dose (NCT05539430; open to enrollment early 2023). During prescreening, that may occur as early as at initial diagnosis, we will screen subjects for tumor expression of CLDN18.2 by IHC of ≥ 1+ in ≥ 50% of tumor cells. Inclusion criteria include: must be ≥18 and ≤75 years old; histologically/cytologically confirmed unresectable, locally advanced, or metastatic adenocarcinoma of the GC, EC, GEJC, and PC; progressed on at least standard 1st line therapy; ECOG PS 0 or 1; life expectancy > 4 months per investigator judgment; and adequate organ function per protocol. The study has 2 parts. In Part A (dose escalation), 12 to 21 subjects with GC, EC, or GEJC will be enrolled in up to 3 planned dose level cohorts (0.5X106, 1.5X106, and 3.0X106 CAR+ viable T cells/kg), to determine the recommended dose for expansion (RDE). In Part B (dose expansion) the RDE will be administered to up to 35 subjects with GC, EC, and GEJC in one expansion cohort and PC in another cohort (n=11-17 for GC/EC/GEJ, to total 23 subjects when pooling with RDE-treated subjects from part A; n=18 for PC). LB1908 will be manufactured from autologous T cells collected via PMBC apheresis. Subjects may receive optional bridging therapy followed by lymphodepleting chemotherapy with fludarabine 30 mg/m2/day and cyclophosphamide 300 mg/m2/day for 3 days. One infusion of LB1908 will then be administered, and subjects will be followed post-infusion for safety, laboratory, and disease assessments. Primary endpoints are incidence, duration, and severity of AEs and laboratory abnormalities (Parts A and B); and frequency of DLTs at each dose level (Part A). Secondary and exploratory endpoints include: objective response rate, disease control rate, duration of response, progression-free survival, characterization of PK by CAR-positive T cell counts, CAR transgene level in blood, effusions, and target tissues, and evaluation of immunogenicity by presence of anti-LB1908 antibodies. Acknowledgments: This study is funded by Legend Biotech USA Inc. Clinical trial information: NCT05539430 .

A phase Ia/Ib, open-label, dose escalation study of the TRAILR2 agonist BI 905711 in combination with chemotherapy (CT) in patients (pts) with advanced GI cancers.

TPS820 Background: Activation of the tumor necrosis factor-related apoptosis-inducing ligand receptor 2 (TRAILR2) induces apoptosis via the extrinsic pathway. Targeting TRAILR2 presents an attractive therapeutic strategy, but some early TRAILR2 agonists showed low efficacy or severe hepatotoxicity. BI 905711 (TRAILR2 agonist) is a novel, liver-sparing, tetravalent bispecific antibody that cross-links TRAILR2 with the membrane protein cadherin 17 (CDH17; highly expressed in GI cancers), inducing CDH17-dependent TRAILR2 oligomerization. CDH17 is not expressed in normal hepatocytes, thus increasing BI 905711 selectivity to GI cancer cells while sparing hepatocytes. Preclinical models and studies in colorectal cancer (CRC) and pancreatic ductal adenocarcinoma (PDAC) showed BI 905711 activity ± CT, and synergy with standard of card CT irinotecan, respectively. Methods: This Phase Ia/Ib, open-label, multicenter study (NCT05087992) aims to determine the maximum tolerated dose (MTD), recommended dose for expansion (RDE), pharmacokinetics (PK), and efficacy of BI 905711 with CT (FOLFIRI; irinotecan, leucovorin, and fluorouracil) ± bevacizumab (BEV) in pts with advanced GI cancers. Up to 100 pts with histologically/cytologically confirmed, advanced, unresectable, or metastatic GI cancers will be enrolled. In Phase Ia, ~20 pts with CRC will receive BI 905711 intravenously every two weeks at escalating doses (starting dose 0.6 mg/kg) on Day 3 of 14-day cycles, + FOLFIRI and BEV (5 mg/kg intravenous infusion for 30 minutes) on Day 1. A Bayesian logistic regression model with overdose control based on dose-limiting toxicities (DLTs) during the MTD evaluation period (first 2 cycles) will guide BI 905711 dose escalation. BI 905711 will be administered until disease progression, unacceptable toxicity, or other reasons requiring treatment discontinuation. In Phase Ib, pts with CRC or PDAC will be enrolled to one of two dose expansion cohorts. In the CRC cohort, pts with prior progression on oxaliplatin-based therapy will be randomized 2:1 to receive FOLFIRI and BEV ± BI 905711. In the PDAC cohort, pts with CDH17+ PDAC with prior progression on gemcitabine-based first-line therapy will receive FOLFIRI + BI 905711. Both cohorts will receive BI 905711 at the RDE defined in Phase Ia. A safety run-in period will confirm the Phase Ia RDE result before enrolling pts to the PDAC cohort. Primary endpoints: MTD based on incidence of DLTs (Phase Ia) and confirmed objective response (OR; RECIST 1.1; Phase Ib). Secondary endpoints include PK assessments (Phase Ia), progression-free survival, tumor shrinkage, duration of OR, and disease control (Phase Ib). Further endpoints include immunogenic response assessment and pharmacodynamic biomarker modulation. As of September 2022, eight pts have been enrolled; one additional pt is in screening. The study is ongoing. Clinical trial information: NCT05087992 .

A phase 1/2 open-label study to evaluate the safety, tolerability, pharmacokinetics, pharmacodynamics, and preliminary antitumor activity of OTX-2002 as a single agent and in combination with standard of care in patients with hepatocellular carcinoma and other solid tumor types known for association with the MYC oncogene (MYCHELANGELO I).

TPS627 Background: MYC, or c-MYC, is a master regulator of gene expression that controls cell growth and proliferation. Dysregulation of MYC is frequently identified in various cancer types, including hepatocellular carcinoma (HCC), where it is overexpressed in up to 70% viral and alcohol-related disease.1 While MYC represents an attractive therapeutic target, it has historically been considered undruggable due to a lack of a structured binding pocket and its tightly autoregulated expression. OTX-2002 is a first-in-class, engineered and programable mRNA therapeutic called Omega Epigenomic Controllers (OECs) that modulates MYC gene expression pre-transcriptionally by creating epigenetic marks at two different structural and regulatory elements within the insulated genomic domain where MYC resides. In vitro studies have demonstrated that downregulation of MYC through OTX-2002 led to loss of viability in HCC cells while sparing normal hepatocytes. In HCC xenograft mouse models, OTX-2002 demonstrated anti-tumor activity as monotherapy and in combinations with standard of care therapies in HCC.2 Methods: OTX-2002 is being evaluated in an open-label, non-randomized, phase 1/2 study (MYCHELANGELO I) in patients with HCC and other advanced solid tumor types (NCT05497453). The study consists of two parts. Part 1 dose escalation explores ascending doses of intravenous OTX-2002 monotherapy given every 2 weeks to identify dose limiting toxicities, maximum tolerated dose, and recommended dose for expansion (RDE) in patients with HCC and other solid tumors using a classic 3+3 design. Upon identification of the RDE, a monotherapy expansion in advanced HCC patients is planned to explore the preliminary anti-tumor activity of OTX-2002. Part 2 will evaluate OTX-2002 in combination with HCC standard of care in the same HCC population as that of Part 1 expansion. The safety of OTX-2002 at the selected dose in combination with a tyrosine kinase inhibitor or immune checkpoint inhibitor will be evaluated in a safety run-in; expansion will follow to identify the preliminary anti-tumor activity of the combinations. Key eligibility criteria for HCC patients include: 1) Barcelona Clinical Liver Cancer (BCLC) stage B or C disease, 2) Child-Pugh A liver function, 3) received at least 1 prior systemic therapy. The MYCHELANGELO I study began enrollment in August 2022, and Part 1 dose escalation is ongoing in the US.

First-in-Human Study of Elvn-001, a Highly Selective BCR::ABL1 Tyrosine Kinase Inhibitor, in Patients with Chronic Myeloid Leukemia Who Failed Previous Tyrosine Kinase Inhibitor Therapies

Background: Despite the benefits BCR::ABL1 tyrosine kinase inhibitors (TKIs) have provided altering the natural history of chronic myeloid leukemia (CML), resistance/lack of response and intolerability occurs. ELVN-001 is a highly selective small molecule active site inhibitor of ABL1 that does not significantly inhibit the receptor tyrosine kinases PDGFR, KIT, VEGFR2 or the Src-family (eg SRC, LCK, LYN, FYN). In vitro data also supports ELVN-001 targeting the most common CML mutation, T315I and not being a substrate for drug efflux transporters such as BCRP, which may contribute to resistance or sensitivity to other TKIs. Non-clinical data suggests ELVN-001 has a favorable absorption, distribution, metabolism, elimination and a pharmacokinetic (PK) profile supporting once daily (QD) dosing, low risk of QTc prolongation, and potential to avoid drug-drug interactions, particularly CYP-mediated. This first-in-human (FIH) study will evaluate the safety, tolerability, PK and preliminary anti-CML activity of ELVN-001 in patients (pts) with chronic (CP) or accelerated phase CML with and without T315I mutations. Objectives: The primary objectives are to determine the recommended doses for expansion (RDE) and to evaluate the safety and tolerability of ELVN-001. Secondary objectives are to assess the PK profile and preliminary efficacy. Design: A phase 1 open-label, multi-center, dose escalation and expansion study. Eligible pts are adults with CP and AP CML who are intolerant or have failed (as per ELN 2020 Recommendations) available TKIs known to be active for treatment of their CML. Other key eligibility criteria are Eastern Cooperative Oncology Group performance status 0-2, adequate bone marrow, renal and liver function, and resolved adverse effects of prior therapy. Prior marrow transplant is allowed. CML with point mutations E255, Y253, G250, F317 or Q252 are excluded. Successive cohorts will receive escalating doses of ELVN-001 starting at 10 mg QD. Dosing will be continuous in 28-day cycles until treatment failure, disease progression or unacceptable toxicity. A standard 3+3 dose escalation will be used, with PK/pharmacodynamic modeling to identify the RDEs, assuming toxicity is not dose limiting. Safety and efficacy of ELVN-001 will be further explored in CP-CML without T315I mutations and a cohort of T315I mutated CP-CML. Mutational analyses by Sanger and NGS will be conducted at baseline and end of treatment. Main Outcomes: Primary endpoints are dose limiting toxicities, adverse events, laboratory and ECG abnormalities. Secondary endpoints are PK parameters, response based on BCR-ABL transcript levels by quantitative PCR and hematology. Conclusions: This FIH study will evaluate dosing, safety, tolerability, PK profile and preliminary efficacy of ELVN-001 in CP-CML with and without T315I mutation. Study sponsor: Enliven Therapeutics. NCT05304377 ELVN-001-101 Schema: Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

AML-143 Trial in Progress: Phase Ib/II Study of Siremadlin in Combination With Venetoclax + Azacitidine in Patients With Acute Myeloid Leukemia (AML) Who Are Ineligible for Intensive Chemotherapy (IC)

Treatments for AML patients unfit for IC are limited. Venetoclax+hypomethylating agents (HMAs) demonstrated improved survival; however, relapse rates are high, and most patients remain measurable residual disease (MRD) positive. Siremadlin is a selective inhibitor of the tumor protein 53 (p53)-murine double minute-2 (MDM2) interaction. AML patients treated with siremadlin experienced a tolerable safety profile and preliminary antitumor activity in a Phase I study (NCT02143635). Initial results from a Phase lb study exploring siremadlin+venetoclax showed promising antileukemic activity in patients with relapsed/refractory AML (NCT03940352). To describe the study design of a Phase lb/II study assessing the safety and efficacy of siremadlin+venetoclax+azacitidine in AML patients unfit for IC (NCT05155709). The study will consist of a safety run-in (part 1) and an expansion phase (part 2). Adult AML patients unfit for IC due to age (≥75 years) or comorbidities are eligible. Patients with TP53 mutation or del17p are excluded. Two subpopulations will be evaluated: patients with prior suboptimal response (no CR, CRh, CRi, or morphologic leukemia-free state) after 2-4 cycles of first-line venetoclax+azacitidine (Arm 1) and patients with newly diagnosed AML with high-risk features that confer a low likelihood of response to venetoclax+HMAs (adverse genetic risk stratification per European Leukemia Network, 2017; Arm 2). Safety run-in/part 1: siremadlin 20 or 30 mg from Day (D)1 to D5 in each 28-day cycle with venetoclax+azacitidine. Arm 1: patients will continue receiving their tolerated venetoclax+azacitidine doses prior to study enrollment. Arm 2: venetoclax will be increased over 3 days to a target daily dose of 400 mg and azacitidine (75 mg/m2) from D1-D7 or from D1-D5, and D8+D9. Upon confirmation of the recommended dose for expansion (RDE) for each arm, enrollment for the expansion phase/part 2 will open; patients will be treated with siremadlin at the RDE in combination with venetoclax+azacitidine. Primary endpoints: incidence of dose-limiting toxicities (Arms 1 and 2 separately) and CR rate (Arm 1). Secondary endpoints: safety and tolerability; CR rate (Arm 2); CR/CRh and CR/CRi rates, duration of CR, CRi, and CRh; OS; early mortality; MRD; pharmacokinetics.