Dose Expansion Cohort Research Articles

Adavosertib in Combination with Olaparib in Patients with Refractory Solid Tumors: An Open-Label, Dose-Finding, and Dose-Expansion Phase Ib Trial.

Adavosertib is a first-in-class, selective small-molecule inhibitor of Wee1. Olaparib is an inhibitor of poly(ADP-ribose) polymerase (PARP). Preclinical data suggest that adavosertib enhances the antitumor effect of PARP inhibitors. The safety, tolerability, and efficacy of adavosertib plus olaparib were evaluated in patients with refractory solid tumors to define the maximum tolerated dose (MTD) and recommended phase II dose (RP2D). Eligible patients in part A (dose finding) had a refractory solid tumor for which there is no established treatment and had received ≥ 1 prior course of systemic therapy; in part B (dose expansion), patients had platinum-sensitive extensive-stage or relapsed small-cell lung cancer (SCLC). Patients received adavosertib [once (qd) or twice daily (bid)] for 3 consecutive days with 4 days off treatment (3/4), or 5 consecutive days with 2 days off (5/2), plus olaparib (bid) for 14 or 21 days of a 21-day cycle. A total of 130 patients were enrolled in the study, 120 in part A and 10 in part B. The MTD for adavosertib bid was 175 mg (days 1-3, 8-10/21-day cycle) plus continuous olaparib 200 mg bid; the once-daily MTD (and RP2D) was adavosertib 200 mg (days 1-3, 8-10/21-day cycle) plus continuous olaparib 200 mg bid. In the MTD/RP2D cohort, one patient (7%) experienced a dose-limiting toxicity (DLT) of thrombocytopenia. The most common treatment-related adverse events (TRAEs) in the cohorts in which MTD/RP2D for bid dosing and RP2D for qd dosing were determined were fatigue (64.3% and 15.4%, respectively), diarrhea (42.9% and 30.8%), decreased appetite (35.7% and 23.1%), nausea (35.7% and 15.4%), and anemia (35.7% and 38.5%). In the SCLC dose-expansion cohort, TRAEs occurred in eight patients (88.9%), including thrombocytopenia (66.7%) and anemia (55.6%). In part A, objective response rate (ORR) was 14.8% [95% confidence interval (CI) 8.7-22.9] overall; for the cohorts in which MTD/RP2D for bid dosing and RP2D for qd dosing were determined, ORR was 30.8% (9.1-61.4) and 9.1% (0.2-41.3), respectively. ORR was 11.1% [95% CI 0.3-48.2; one partial response (PR)], disease control rate was 22.2% (2.8-60.0; one PR, one stable disease), and median progression-free survival was 1.5 months (1.3-4.2) in the SCLC dose-expansion cohort. Adverse events and DLTs observed in the bid MTD and once-daily MTD/RP2D dosing schedules were manageable and consistent with known adavosertib and olaparib safety profiles. Limited antitumor activity was observed with adavosertib plus olaparib combination therapy. ClinicalTrials.gov, NCT02511795 (registration: 28 July 2015).

Benmelstobart plus anlotinib in patients with EGFR-positive advanced NSCLC after failure of EGFR TKIs therapy: a phase I/II study

The effect of immune‐based therapies on patients with epidermal growth factor receptor (EGFR)-positive advanced non-small cell lung cancer (NSCLC) resistant to EGFR tyrosine kinase inhibitor (TKI) therapy remains unclear. The ALTER-L038 study aimed to evaluate efficacy and safety of a chemotherapy-free combination of benmelstobart, an anti-programmed cell death ligand 1 antibody, and anlotinib, a small-molecule multi-target anti-angiogenic TKI, in EGFR-positive advanced NSCLC patients who progressed after EGFR TKI therapy. Patients were enrolled in a phase I/II study. In phase I (dose-escalation), patients received anlotinib (8, 10, 12 mg) plus benmelstobart (1200 mg). Recommended phase II dose, determined during phase I, was used in phase II dose-expansion cohort. Primary endpoints were maximum tolerable dose in phase I and progression-free survival (PFS) in phase II. At the data cutoff date (March 10, 2024), 55 patients were enrolled in phase II dose-expansion cohort. Median PFS of patients included in phase II cohort was 9.0 months, median overall survival was 28.9 months, objective response rate was 25.5%, disease control rate was 87.3%, and median duration of response was 19.8 months. Incidence of grade ≥3 treatment-related adverse events in study population was 25.5% (14/55), whereas grade ≥3 immune-related adverse events occurred in 10.9% (6/55) of patients. Benmelstobart plus anlotinib showed promising anti-tumor efficacy with tolerable safety profile, supporting the value of further development of this convenient chemotherapy-free regimen for patients with EGFR-positive advanced NSCLC who progressed after EGFR TKI therapy. Trial Registration: ChiCTR1900026273.

A Phase I First-in-Human Study of ABBV-011, a Seizure-Related Homolog Protein 6-Targeting Antibody-Drug Conjugate, in Patients with Small Cell Lung Cancer.

Seizure-related homolog protein 6 (SEZ6) is a novel target expressed in small cell lung cancer (SCLC). ABBV-011, a SEZ6-targeted antibody conjugated to calicheamicin, was evaluated in a phase I study (NCT03639194) in patients with relapsed/refractory SCLC. We report initial outcomes of ABBV-011 monotherapy. ABBV-011 was administered intravenously once every 3 weeks during dose escalation (0.3-2 mg/kg) and expansion. Patients with SEZ6-positive tumors (≥25% of tumor cells with ≥1+ staining intensity by IHC) were preselected for expansion. Safety, tolerability, antitumor activity, and pharmacokinetics were evaluated. As of August 2022, 99 patients received ABBV-011 monotherapy [dose escalation, n = 36; Japanese dose evaluation, n = 3; dose expansion, n = 60 (1 mg/kg, n = 40)]; the median age was 63 years (range, 41-79 years). Also, 32%, 41%, and 26% of patients received 1, 2, and ≥3 prior therapies, respectively. The maximum tolerated dose was not reached through 2.0 mg/kg. The most common treatment-emergent adverse events were fatigue (50%), nausea (42%), and thrombocytopenia (41%). The most common hepatic treatment-emergent adverse events were increased aspartate aminotransferase (22%), increased γ-glutamyltransferase (21%), and hyperbilirubinemia (17%); two patients experienced veno-occlusive liver disease. The objective response rate was 19% (19/98). In the 1-mg/kg dose-expansion cohort (n = 40), the objective response rate was 25%; the median response duration was 4.2 months (95% confidence interval, 2.6-6.7); and the median progression-free survival was 3.5 months (95% confidence interval, 1.5-4.2). ABBV-011 1.0 mg/kg every 3 weeks monotherapy was well tolerated and demonstrated encouraging antitumor activity in heavily pretreated patients with relapsed/refractory SCLC. SEZ6 is a promising novel SCLC target and warrants further investigation.

A Phase II Study Assessing Long-term Response to Ibrutinib Monotherapy in Recurrent or Refractory CNS Lymphoma.

Ibrutinib is a first-in-class inhibitor of Bruton tyrosine kinase. We previously reported the safety and short-term antitumor activity of ibrutinib in 20 patients with relapsed or refractory (r/r) primary central nervous system (CNS) lymphoma (PCNSL) or secondary CNS lymphoma (SCNSL). We enrolled 26 additional patients with r/r PCNSL/SCNSL into the dose-expansion cohort of the trial into a combined cohort of 46 patients (31 with PCNSL and 15 with SCNSL). Patients received ibrutinib at 560 or 840 mg daily in the dose-escalation cohort and ibrutinib at 840 mg daily in the expansion cohort. The median follow-up was 49.9 and 62.1 months for patients with PCNSL and SCNSL, respectively. We sequenced DNA from available tumor biopsies and cerebrospinal fluid collected before and during ibrutinib therapy. Tumor responses were observed in 23/31 (74%) patients with PCNSL and 9/15 (60%) patients with SCNSL, including 12 complete responses in PCNSL and 7 in SCNSL. The median progression-free survival (PFS) for PCNSL was 4.5 months [95% confidence interval (CI), 2.8-9.2] with 1-year PFS at 23.7% (95% CI, 12.4%-45.1%). The median duration of response in the 23 PCNSL responders was 5.5 months. The median PFS in SCNSL was 5.3 months (95% CI, 1.3-14.5) with a median duration of response of 8.7 months for the 9 responders. Exploratory biomarker analysis suggests that mutations in TBL1XR1 may be associated with a long-term response to ibrutinib in PCNSL (P = 0.0075). Clearance of ctDNA from cerebrospinal fluid was associated with complete and long-term ibrutinib responses. Our study confirms single-agent activity of ibrutinib in r/r CNS lymphoma and identifies molecular determinants of response based on long-term follow-up.

1598P Xaluritamig, a STEAP1 x CD3 XmAb 2+1 immune therapy, in patients (pts) with metastatic castration-resistant prostate cancer (mCRPC): Initial results from dose expansion cohorts in a phase I study

1598P Xaluritamig, a STEAP1 x CD3 XmAb 2+1 immune therapy, in patients (pts) with metastatic castration-resistant prostate cancer (mCRPC): Initial results from dose expansion cohorts in a phase I study

762P First results from phase II dose expansion cohort of transcon IL-2 β/γ in combination with standard of care chemotherapy for platinum resistant ovarian cancer (PROC) in the IL Believe trial

762P First results from phase II dose expansion cohort of transcon IL-2 β/γ in combination with standard of care chemotherapy for platinum resistant ovarian cancer (PROC) in the IL Believe trial

738P Global, phase Ib dose-expansion cohort of E7386 + lenvatinib (LEN) in patients (pts) with advanced (a) endometrial cancer (EC) that progressed on platinum-based chemotherapy (CTx) and an anti-PD-(L)1 immunotherapy (IO)

738P Global, phase Ib dose-expansion cohort of E7386 + lenvatinib (LEN) in patients (pts) with advanced (a) endometrial cancer (EC) that progressed on platinum-based chemotherapy (CTx) and an anti-PD-(L)1 immunotherapy (IO)

Efficacy and safety of bintrafusp alfa in 2 phase I expansion cohorts with advanced HCC.

Simultaneous inhibition of the TGF-β and programmed cell death 1 ligand 1 pathways provides a potential novel treatment approach. Bintrafusp alfa, a first-in-class bifunctional fusion protein composed of the extracellular domain of TGF-βRII (a TGF-β "trap") fused to a human IgG1 monoclonal antibody blocking programmed cell death 1 ligand 1, was evaluated in patients with advanced HCC. In this global, open-label, phase I study (NCT02517398), patients with programmed cell death 1 ligand 1-unselected HCC who failed or were intolerant to ≥1 line of sorafenib received bintrafusp alfa 1200mg every 2 weeks in a dose-escalation (n = 38) or dose-expansion (n = 68) cohort until confirmed progression, unacceptable toxicity, or trial withdrawal. The primary endpoint was the best overall response per Response Evaluation Criteria in Solid Tumors version 1.1 by an independent review committee. Secondary endpoints included investigator-assessed best overall response, safety, and pharmacokinetics. Median follow-up times (range) were 41.4 (39.8-44.2) and 38.6 (33.5-39.7) months in the dose-escalation and dose-expansion cohorts, respectively. The objective response rate was below the prespecified 20% objective response rate threshold set to evaluate the efficacy of bintrafusp alfa in both cohorts (10.5% and 8.8%, respectively). Median overall survival and progression-free survival, respectively, were 13.8 and 1.5 months in the dose-escalation cohort and 13.5 and 1.4 months in the dose-expansion cohort. Treatment-related adverse events occurred in 78.9% and 64.7% of patients in the respective cohorts (grade ≥3 in 18.4% and 25.0% of patients). Bintrafusp alfa showed moderate clinical activity and a safety profile consistent with previous studies of bintrafusp alfa in patients with advanced HCC.

A phase Ib/II study of pacritinib, an interleukin 1 receptor associated kinase 1 (IRAK1) inhibitor, in patients (pts) with solid tumors harboring the 1q21.3 copy number amplification (CNA).

43 Background: The role of IRAK1 pathway in inflammatory and immune response is established in autoimmune diseases but less well-understood in cancer. Chromosome 1q21.3 CNA detected in plasma cell-free DNA was observed in pts with advanced solid tumors, and associated with IRAK1 upregulation. In preclinical animal models, IRAK1 upregulation promoted tumorigenesis, while its inhibition led to decreased tumor growth. Pacritinib is a JAK2/FLT3 inhibitor that is FDA approved for treatment in myelofibrosis, but also have known activity against IRAK1. We hypothesize that pacritinib may be effective in disease control of pts with plasma 1q21.3 CNA. Methods: A phase Ib/II clinical trial was designed to investigate the efficacy of pacritinib in pts with treatment (rx) refractory solid tumors harboring 1q21.3 CNA. Serial pt tumor and blood samples were collected and analyzed to elucidate the effect of IRAK1 inhibition on tumor microenvironment and systemic immune modulation. Results: 330 patients were screened, 1q21.3 CNA was detected in 30.1% of pts. Highest incidence of 1q21.3 CNA positivity was detected in breast cancer (39.8%), colorectal cancer (39.7%) and lung cancer (36.1%). 12 pts were commenced on rx over 3 dose levels (DL) (DL1: n=6, DL2: n=3, DL3: n=3). At DL1 (200mg BID), no DLTs were observed, but 2 pts had G3 transaminitis attributed to drug/disease, and 1 pt had intolerable G2 rash; decision was made for dose reduction. At DL2 (200mg OM, 100mg ON), no DLTs were observed. Reescalation to 200mg BID (DL3) was carried out with no DLT observed. Pacritinib at 200mg BD was declared the recommended phase II dose in pts with solid tumors. In the dose expansion cohort, 8 pts (4 colorectal cancer, 3 hepatobiliary [HPB] cancer, 1 lung cancer) have been enrolled thus far. No objective responses were observed. Within pts with HPB tumors, 1 pt with pancreatic cancer had a progression-free survival (PFS) of 25.0 weeks, and 1 pt with cholangiocarcinoma had a PFS of 15.9 weeks. Preliminary analysis of serial tumor biopsy samples suggest an expansion of CD8+ T cell population with pacritinib rx. Serial peripheral blood mononuclear cells analysis showed no significant trend in change in CD8+ T cell population, but a predominance of PD-1+ T cells with rx, and also an increase in CD4+ T cell population. In the myeloid cell population, there appears to be decrease in dendritic cell population, but no significant change in trend of macrophage was observed. Conclusions: Pacritinib at 200mg BID is safe and tolerable in pts with solid tumors. IRAK1 inhibition appears to modulate immune cell populations both in the tumor microenvironment and systemic circulation. Dose expansion is underway, with potential signal of disease control in HPB tumors. Clinical trial information: NCT04520269 .

Preclinical evaluation and phase 1 study of the PI3Kα/δ inhibitor TQ-B3525 in Chinese patients with advanced cancers.

Phosphatidylinositol 3-kinase (PI3K) inhibitors transformed management of various malignancies. This study preclinically characterized TQ-B3525 (dual PI3Kα/δ inhibitor) and assessed the recommended phase 2 dose (RP2D), safety, efficacy, and pharmacokinetics in relapsed or refractory (R/R) lymphoma or advanced solid tumors (STs). Oral TQ-B3525 was given at eight dose levels on a 28-day cycle. Primary end points were dose-limiting toxicity (DLT), maximum tolerated dose (MTD), and safety. TQ-B3525 showed high selectivity and suppressed tumor growth. Between June 12, 2018, and November 18, 2020, 80 patients were enrolled (63 in dose-escalation cohort; 17 in dose-expansion cohort). Two DLTs occurred in two (two of 63, 3.2%) DLT-evaluable patients; MTD was not identified. TQ-B3525 at 20 mg once daily was selected as RP2D. Grade 3 or worse treatment-related adverse events mainly included hyperglycemia (16.3%), neutrophil count decreased (15.0%), and diarrhea (10.0%). Two (2.5%) treatment-related deaths were reported. Sixty patients with R/R lymphoma and 11 advanced STs demonstrated objective response rates of 68.3% and 9.1%, disease control rates of 91.7% and 54.6%, median progression-free survivals of 12.1 and 1.1 months; median overall survivals were not reached. TQ-B3525 exhibited rapid absorption and a nearly proportional increase in exposure. Acceptable safety and promising efficacy support further investigation of TQ-B3525 (20 mg once daily) for R/R lymphoma.

Abstract PO-003: Peripheral blood and tumor tissue biomarkers associated with epcoritamab response in patients with relapsed or refractory diffuse large B-cell lymphoma: Data from the dose-expansion cohort of the phase 1/2 EPCORE NHL-1 trial (NCT03625037)

Abstract Introduction: Epcoritamab, a CD3xCD20 bispecific antibody, demonstrated deep and durable clinical responses in patients (pts) with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL). We evaluated the correlation of peripheral blood (PB) and tumor tissue biomarkers with clinical response to epcoritamab. Methods: Pts received priming (0.16 mg), intermediate (0.8 mg) and full epcoritamab doses (48 mg). Absolute lymphocyte count (ALC) was analyzed locally. Blood immunophenotyping was assessed by flow cytometry, plasma cytokines by MSD assay, and %CD20+ in tumors by immunohistochemistry (n=117). Gene expression in baseline tumor biopsies was evaluated using HTG EdgeSeq (n=70). Microenvironment scores were estimated from gene expression as a sum of immune (B/T, NK, dendritic, and myeloid cells) and stromal scores (adipocytes, fibroblasts, and endothelial cells). Best overall response as of April 21, 2023 was assessed by independent review committee using Lugano criteria. P values were based on Wilcoxon rank-sum test. Results: In PB at baseline, significantly higher ALC (P=0.031), CD4+ (P=0.0038), and CD8+ (P=0.043) T-cell levels were observed in responders (R) vs nonresponders (NR). Similarly, CD4+ (P=0.02) and CD8+ (P=0.03) signatures and immune and microenvironment scores were higher in baseline tumor tissue in R vs NR. In PB CD8+ T cells, NR showed higher %PD1+ (P=0.016), %TIM3+ (P=0.048), and %TIM3+TIGIT+ (P=0.045). High tumor %CD20+ (≥90%) was observed in most pts (n=97/117); lower %CD20+ (<50%) was observed only in 6 NRs and 1 R. Epcoritamab treatment caused a rapid decline in circulating B cells irrespective of clinical response. Transient reductions in PB CD4+ and CD8+ T cells (ie, margination) were observed within 24 hours (H) after each dose during cycle (C) 1 and were more pronounced in R vs NR. Magnitude of margination for CD8+ T cells after the priming and intermediate doses was significantly lower in NR (reduced by median 22 & 41%) vs R (57 & 70%), while the difference in CD4+ T cells was not as pronounced in NR vs R, resulting in a substantially lower CD4+/CD8+ ratio in NR vs R. In C1, epcoritamab led to an increase of PB CD4+ and CD8+ T cells expressing activation/proliferation markers, with significantly higher fold change from baseline in R vs NR, especially within 24H post-priming dose. Early cytokine peaks of IFNy and IL-10 were more pronounced 6–24H post-priming dose and 6–14H post-first full dose in complete R vs pts with progressive disease. Epcoritamab also appeared to modulate NK cell numbers (under further investigation). Conclusions: In pts with R/R DLBCL, T-cell abundance and increased margination, activation, proliferation, and modulation of cytokines differed in R vs NR. These findings are consistent with epcoritamab’s mechanism of action and demonstrate the dependency on proper T-cell engagement for clinical benefit. Our findings also revealed differences in the dynamics of CD4+ and CD8+ T-cell margination in R vs NR, warranting further investigation. Previously submitted in part to EHA 2024. Citation Format: Monica Wielgos-Bonvallet, Jimin Zhang, Han Si, Kubra Karagoz, Melih Acar, Yasmin Karimi, Herve Ghesquieres, Michael Roost Clausen, Iş?l Alt?ntaş, Binhuan Wang, Wissam Assaily, Matthew Loya, Gregg Masters, Anantharaman Muthuswamy, Brandon Higgs, Mariana Sacchi, Tahi Ahmadi, Mark Fereshteh, Edith Szafer-Glusman, David Soong, Maria Jure-Kunkel, Andrew J Steele. Peripheral blood and tumor tissue biomarkers associated with epcoritamab response in patients with relapsed or refractory diffuse large B-cell lymphoma: Data from the dose-expansion cohort of the phase 1/2 EPCORE NHL-1 trial (NCT03625037) [abstract]. In: Proceedings of the Fourth AACR International Meeting on Advances in Malignant Lymphoma: Maximizing the Basic-Translational Interface for Clinical Application; 2024 Jun 19-22; Philadelphia, PA. Philadelphia (PA): AACR; Blood Cancer Discov 2024;5(3_Suppl):Abstract nr PO-003.

TRLS-15. “TAZNI”: A PHASE I/II COMBINATION TRIAL OF TAZEMETOSTAT WITH NIVOLUMAB AND IPILIMUMAB FOR CHILDREN WITH INI1-NEGATIVE OR SMARCA4-DEFICIENT TUMORS (NCT05407441)

Abstract BACKGROUND Recent pediatric trials with EZH2 inhibitor tazemetostat monotherapy have demonstrated efficacy and disease stabilization in children with relapsed INI1/SMARCA4-deficient tumors: overall response rate (ORR) 14% in all patients (dose expansion cohort), and 24%, 33% and 22% response rates in ATRT, chordoma and epithelioid sarcoma, respectively (NCT02601937); and prolonged disease stabilization >6 months (NCT03213665). Leveraging the role of EZH2 in tumor immunity and increased immune signaling by tazemetostat, we hypothesized that combining this EZH2 inhibitor with checkpoint inhibitors may benefit pediatric patients with these rare cancers. METHODS “TAZNI” is a phase 1/2, multi-center trial of tazemetostat, nivolumab and ipilimumab for children with INI1/ SMARCA4-deficient tumors, administered either after standard upfront therapy or in the relapsed setting. All patients will receive standard nivolumab and ipilimumab doses/dosing schedule, with continuous tazemetostat dosing determined by disease strata: Stratum A- subjects with ATRT; Stratum B- all other (non-ATRT) tumors. Each stratum is subdivided by disease status: A1/B1- refractory disease; A2/B2- relapsed disease; and A3/B3- no evidence of disease. Part 1 of the study consists of two concurrent “rolling six” phase 1 studies to identify the recommended phase 2 dose (RP2D) by disease stratum. Two dose levels are planned, with one dose de-escalation. Part 2 will consist of two phase 2 studies to estimate the ORRs in substrata A1 and A2, in a Simon’s 2-stage design at the RP2D. All other substrata will have descriptive analyses. Patients may receive up to 26 cycles of therapy. Key inclusion/exclusion criteria include INI1 or SMARCA4 loss (by immunohistochemistry or molecular confirmation); age 6 mo - 21 yo; no prior immunotherapy; limited corticosteroid usage; and no concern for hematologic malignancy. This trial is currently ongoing and open to accrual. To date, four patients have enrolled and additional sites across the US are anticipated to open for enrollment (NCT05407441).

Epcoritamab monotherapy in patients with relapsed or refractory follicular lymphoma (EPCORE NHL-1): a phase 2 cohort of a single-arm, multicentre study

A standard of care and optimal duration of therapy have not been established for patients with multiply relapsed or refractory follicular lymphoma. The aim of this study was to evaluate epcoritamab, a novel CD3 × CD20 bispecific antibody, in the third-line and later setting of follicular lymphoma. EPCORE NHL-1 is a multicohort, single-arm, phase 1-2 trial conducted at 88 sites across 15 countries. Here, we report the primary analysis of patients with relapsed or refractory follicular lymphoma in the phase 2 part of the trial, which included the pivotal (dose expansion) cohort and the cycle 1 optimisation cohort. Eligible patients were aged 18 years or older, had relapsed or refractory CD20+ follicular lymphoma (grade 1-3A), an Eastern Cooperative Oncology Group performance status of up to 2, and had received at least two previous lines of therapy (including an anti-CD20 monoclonal antibody and an alkylating agent or lenalidomide). Patients were treated with subcutaneous epcoritamab 48 mg in 28-day cycles: weekly in cycles 1-3, biweekly in cycles 4-9, and every 4 weeks until disease progression or unacceptable toxicity. To mitigate the risk and severity of cytokine release syndrome, in the pivotal cohort, cycle 1 consisted of a step-up dosing regimen of a 0·16-mg priming dose on day 1 and a 0·80-mg intermediate dose on day 8, followed by subsequent 48-mg full doses and prophylactic prednisolone 100 mg; in the cycle 1 optimisation cohort, a second intermediate dose of 3 mg on day 15, adequate hydration, and prophylactic dexamethasone 15 mg were evaluated during cycle 1 to further reduce risk and severity of cytokine release syndrome. Primary endpoints were independently reviewed overall response rate for the pivotal cohort and the proportion of patients with grade 2 or worse and any-grade cytokine release syndrome for the cycle 1 optimisation cohort. Analyses were done in all enrolled patients who had received at least one dose of epcoritamab. This study is registered with ClinicalTrials.gov, NCT03625037, and is ongoing. Between June 19, 2020, and April 21, 2023, 128 patients (median age 65 years [IQR 55-72]; 49 [38%] female and 79 [62%] male) were enrolled and treated in the pivotal cohort (median follow-up 17·4 months [IQR 9·1-20·9]). The overall response rate was 82·0% (105 of 128 patients; 95% CI 74·3-88·3), with a complete response rate of 62·5% (80 of 128; 95% CI 53·5-70·9). The most common grade 3-4 treatment-emergent adverse event was neutropenia in 32 (25%) of 128 patients. Grade 1-2 cytokine release syndrome was reported in 83 (65%) of 128 patients; grade 3 cytokine release syndrome was reported in two (2%). Immune effector cell-associated neurotoxicity syndrome was reported in eight (6%) of 128 patients (five [4%] grade 1; three [2%] grade 2). Between Oct 25, 2022, and Jan 8, 2024, 86 patients (median age 64 years [55-71]; 37 [43%] female and 49 [57%] male) were enrolled and treated in the cycle 1 optimisation cohort. The incidence of cytokine release syndrome was 49% (42 of 86 patients; eight [9%] grade 2; none of grade 3 or worse), with no reported immune effector cell-associated neurotoxicity syndrome. Epcoritamab monotherapy showed clinically meaningful activity in patients with multiply relapsed or refractory follicular lymphoma, and had a manageable safety profile. Genmab and AbbVie.

Botensilimab plus balstilimab in relapsed/refractory microsatellite stable metastatic colorectal cancer: a phase 1 trial

Microsatellite stable metastatic colorectal cancer (MSS mCRC; mismatch repair proficient) has previously responded poorly to immune checkpoint blockade. Botensilimab (BOT) is an Fc-enhanced multifunctional anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) antibody designed to expand therapy to cold/poorly immunogenic solid tumors, such as MSS mCRC. BOT with or without balstilimab (BAL; anti-PD-1 antibody) is being evaluated in an ongoing expanded phase 1 study. The primary endpoint is safety and tolerability, which was evaluated separately in the dose-escalation portion of the study and in patients with MSS mCRC (using combined dose-escalation/dose-expansion data). Secondary endpoints include investigator-assessed RECIST version 1.1–confirmed objective response rate (ORR), disease control rate (DCR), duration of response (DOR) and progression-free survival (PFS). Here we present outcomes in 148 heavily pre-treated patients with MSS mCRC (six from the dose-escalation cohort; 142 from the dose-expansion cohort) treated with BOT and BAL, 101 of whom were considered response evaluable with at least 6 months of follow-up. Treatment-related adverse events (TRAEs) occurred in 89% of patients with MSS mCRC (131/148), most commonly fatigue (35%, 52/148), diarrhea (32%, 47/148) and pyrexia (24%, 36/148), with no grade 5 TRAEs reported and a 12% discontinuation rate due to a TRAE (18/148; data fully mature). In the response-evaluable population (n = 101), ORR was 17% (17/101; 95% confidence interval (CI), 10–26%), and DCR was 61% (62/101; 95% CI, 51–71%). Median DOR was not reached (NR; 95% CI, 5.7 months–NR), and median PFS was 3.5 months (95% CI, 2.7–4.1 months), at a median follow-up of 10.3 months (range, 0.5–42.6 months; data continuing to mature). The combination of BOT plus BAL demonstrated a manageable safety profile with no new immune-mediated safety signals and encouraging clinical activity with durable responses. ClinicalTrials.gov identifier: NCT03860272.

A phase 1/2, open label study of amivantamab in combination with tyrosine kinase inhibitors among participants with advanced NSCLC harboring ALK, ROS1, and RET gene fusions.

TPS8661 Background: Patients with ALK, ROS1, or RET rearranged NSCLC demonstrate dramatic and sustained responses to tyrosine kinase inhibitors (TKI). Unfortunately, acquired resistance remains a major clinical challenge. The EGFR and MET pathways have been reported as important escape mechanisms for cancer cells treated with highly potent TKIs. Combining amivantamab with ALK, ROS1, or RET TKIs upon radiographic progression represents a rational combination strategy in addressing TKI mediated resistance. Methods: This is an open-label, multicenter, Phase 1b / 2 study of amivantamab in combination with TKIs among participants with advanced NSCLC harboring ALK, ROS1, and RETgene fusions progressing on FDA-approved TKIs for their respective oncogene. Participants must be on their TKI at the same dose for at least 3 months prior to enrolling in the study. A pre-treatment biopsy is required to rule out neuroendocrine transformation and for translational objectives. Local confirmation of an ALK, ROS1, or RET gene fusion through tissue or circulating tumor DNA (ctDNA) assessment is allowed. Plasma collection for ctDNA assessments will occur prior to treatment, on C3D1, and post-treatment. This study will have both a safety lead-in cohort and a dose expansion cohort. A safety lead-in cohort will be treated with amivantamab at the RP2D in combination with their ALK, ROS1, or RET TKI. The primary endpoint will be dose-limiting toxicity (DLT) within the first cycle of dosing at a given dose level. A Bayesian optimal interval (BOIN) design will be employed as a safety lead-in using a dose de-escalation design to find the maximum tolerated dose (MTD) of amivantamab in combination with a standard fixed dose of common ALK, ROS1, and RET TKIs. The RP2D dose for amivantamab was previously set at 1050mg (for patients < 80kg) and 1400mg (for patients ≥ 80kg). Patients will be treated in cohorts of size 3, and the maximum sample size for the dose escalation portion of the trial is 12 patients. The dose expansion cohort will evaluate the safety and efficacy of amivantamab (at the RP2D dose) in combination with standard FDA-approved doses of ALK, ROS1, and RET TKIs. The primary endpoint will be objective response rate (ORR). All patients enrolled at the RP2D level will be included in the phase II efficacy analysis, including patients enrolled in the safety lead-in cohort. A total of 16 to 35 evaluable patients, depending on the safety of the tested treatments in the dose escalation phase, are expected to be accrued to this study. Relevant exclusion criteria include: (1) prior EGFR directed therapy, (2) prior receipt of a MET monoclonal antibody or MET-ADC, (3) crizotinib use as immediate prior line of therapy, (4) small cell transformation, and (5) active, untreated, CNS metastases. The study has initiated enrollment without DLT and is ongoing. Clinical trial information: NCT05845671 .

A phase 1b/2 study of pivekimab sunirine (PVEK, IMGN632) in combination with venetoclax/azacitidine for patients with newly diagnosed CD123-positive acute myeloid leukemia.

TPS6585 Background: Despite improved outcomes with azacitidine (AZA) and venetoclax (VEN) in newly diagnosed (ND) unfit acute myeloid leukemia (AML), only a subset of patients (pts) respond (CR 37%; CR/CRi 66%) and long-term survival remains inadequate (mOS <15m, DiNardo NEJM 2020). The measurable residual disease (MRD)-negative rate was 41% in AZA-VEN treated pts in VIALE-A which was associated with improved survival (Pratz JCO 2022). CD123 is expressed on the majority of AML blasts and leukemic stem cells while minimally expressed on normal hematopoietic stem cells (Kovtun Blood Adv 2018). Pivekimab sunirine (PVEK, IMGN632) is an antibody-drug conjugate comprising a high-affinity CD123 antibody, cleavable linker, and an indolinobenzodiazepine pseudodimer (IGN) payload. The IGN payload alkylates DNA and causes single strand breaks without crosslinking. IGNs are designed to have high potency against tumor cells, while demonstrating less toxicity to normal marrow progenitors than other DNA-targeting payloads. Clinical data from the first 50 pts in the dose expansion cohorts 1 and 2 with ND AML demonstrated a 76% (22/29) MRD negativity rate (by flow cytometry, negativity threshold <0.1%) (Daver ASH 2023), supporting the continued enrollment of the PVEK+AZA+VEN triplet and further evaluation of the regimen’s antileukemia activity and safety in consideration of potential registration-enabling trials. Methods: This is an open-label, multicenter, phase 1b/2 study of PVEK administered in a combination with AZA+VEN in pts with ND CD123-positive (CD123+ by flow cytometry or IHC) AML, with no prior treatment with hypomethylating agents (HMA). Pts will receive the recommended phase 2 dose of PVEK 0.045 mg/kg IV as a < 30-minute outpatient infusion on day 7, AZA 75 mg/m2 SC or IV daily on days 1 to 7, and VEN 400 mg PO daily for up to 28 days in a 28-day cycle. During cycle 1, a bone marrow evaluation at or around day 21 is required to inform VEN dose duration. Current eligibility criteria for continued enrollment of AML patients unfit for intensive chemotherapy include age ≥ 75 years old, or age < 75 years old with ECOG 2-3, or at least one defined comorbidity. The primary study objectives are to assess antileukemia clinical activity (composite CR [complete remission] rate, overall response rate, duration of remission) and MRD-negativity rates. Key secondary objectives are safety and tolerability, pharmacokinetics and immunogenicity. The PVEK+AZA+VEN triplet in pts with ND unfit AML is currently enrolling across sites in France, Germany, Italy, Spain, UK and USA. Clinical trial information: NCT04086264 .

FURTHER: A global study to evaluate furmonertinib in patients with EGFR mutant NSCLC including uncommon EGFR mutations (FURMO-002).

TPS8666 Background: Furmonertinib (AST2818) is an oral, highly brain-penetrant, and broadly active mutation-selective epidermal growth factor receptor ( EGFR) inhibitor engineered for broad activity and selectivity across EGFRmutations (mts) (1). Furmonertinib is approved in China for first-line advanced NSCLC with EGFR Ex19del or L858R mts based on the progression-free survival benefit observed in the Phase 3 study versus gefitinib (FURLONG). Furmonertinib has also demonstrated promising interim efficacy and safety in patients (pts) with NSCLC harboring EGFR exon 20 insertion (ex20ins) mts with a confirmed overall response rate (ORR) of 78.6% (n=28) by blinded independent central review (BICR) and a preliminary median duration of response (DoR) of 15.2 months in the front-line setting (FAVOUR study; see Han et al., WCLC 2023). Furmonertinib recently obtained FDA Breakthrough Therapy Designation for the treatment of pts with advanced NSCLC with EGFR ex20ins mts. P-loop and αC-helix Compressing (PACC) mts represent another subset of uncommon EGFR mts (2) that are similar to ex20ins mts in narrowing the drug-binding pocket; including G719X, S768I, E709X, L747X, V774M. Preclinical data indicating that furmonertinib is potent in models harboring EGFR PACC mts Developing efficacious, well-tolerated, and CNS-penetrant medicines for NSCLC pts with EGFR ex20ins mts and PACC mts remains an unmet need. Methods: FURTHER (FURMO-002) is the first global trial evaluating furmonertinib in NSCLC pts with EGFR and HER2 mts in North America, Europe, and the Asia-Pacific. FURTHER is a phase 1b, open-label, multicenter study in which pts will be treated orally with furmonertinib daily. For Stage 1 dose-escalation, the primary endpoint is incidence and severity of adverse events, including dose limiting toxicities and has been completed. For Stage 2 dose expansion, approximately 120 pts will be enrolled across 4 expansion cohorts. Stage 2 Cohorts 1-3 dose expansion cohorts will enroll pts with previously treated, locally advanced or metastatic NSCLC pts with either EGFR ex20ins mts, HER2 ex20ins mts, or EGFR activating mts, respectively. Cohorts 1-3 allow enrollment of pts with prior EGFR or HER2-directed therapy. Stage 2 Cohort 4 will enroll EGFR TKI-naïve NSCLC pts with EGFR PACC mts. Key inclusion criteria include documented EGFR or HER2 mts by local testing and measurable disease per RECIST v1.1. Stage 2 primary endpoint is ORR using RECIST v1.1. Key secondary endpoints include progression-free survival and overall survival. Stage 2 enrollment is ongoing. 1. Musib et al., NACLC 2022. 2. Robichaux et al., 2021. Clinical trial information: NCT05364073 .

Dose escalation of KY-0118, PD-1, and IL-2v due-target fusion protein in patients with advanced renal clear cell carcinoma, urothelial carcinoma, and malignant melanoma.

e14505 Background: KY-0118 is an anti-PD1 and IL-2v(variant) fusion protein for advanced solid tumors. The non-α biased design reduces the binding to IL2-Raβγ and enhanced binding to PD-1 & IL2-Rβγ positive TILs to drive increased proliferation and activation of NK and CD8+ T cells without unwanted expansion of Tregs. KY-0118 adopts specific single design, only 67kDa MW thus obtains excellent tumor penetration activity. The preclinical data shows higher antitumor activity in several CDX models compared with nivolumab and IL2wt. KY-0118 monotherapy is currently in Phase I escalation. Methods: The phase I dose escalation is a traditional 3+3 design, KY-0118 on Days 1, 8 and 15, 21-day treatment cycle, 9 dose levels (0.3μg/kg-64μg/kg) or higher doses of 3 to 6 patients are planned. The dose expansion cohort is currently enrolling. The primary endpoint was to evaluate the safety, tolerability, and determine the DLT, MTD, RP2D of KY 0118 when given alone. Secondary objectives are PK/PD characteristics and preliminary evidence of efficacy via ORR per RECIST v1.1 and iRECIST. Results: Up to Jan 31, 2024, 21 patients have been treated, the median number of prior lines of systemic therapy was 2. The dose level 8 (48µg/kg) of DLT observation period is ongoing, no DLT was observed in the administered dose groups. Most of TEAEs are transient grade 1-2, no TEAE led to withdrawal from this study. The most common nonhematologic TRAEs were pyrexia, flu-like symptoms, nausea, fatigue. 2 patients had grade 3 hematologic toxicity. Treatment-related sAEs were observed in one patient (include nausea, vomiting, and pulmonary embolism, now recovered and continuing treatment). No patients experienced complete or partial response, but several showed evidence of antitumor activity, at the dose of 36 ug/kg, 21% shrinkage of target lesions in a patient with RCC, the DCR for the 12, 24, and 36μg/kg dose levels are 33%, 75%, and 67%, respectively. Conclusions: These preliminary data suggest that KY-0118 demonstrated a manageable safety profile and encouraging early evidence of activity has been observed in locally advanced and/or metastatic solid tumors. Enrollment is ongoing, further results are forthcoming. Pts: 21; AEs: 399; TEAEs: 289 (100%); AESI: 13; sAEs: 8. Clinical trial information: NCT06175780 .

First-in-human study of RLY-2608, a pan-mutant and isoform selective PI3Kα inhibitor, as a single agent in patients (pts) with advanced solid tumors and in combination with fulvestrant in pts with advanced breast cancer.

TPS1128 Background: Oncogenic mutations in PIK3CA occur in ~35% of HR+, HER2– breast cancer (BC) and are frequent in multiple solid tumors. The approval of alpelisib, a non-mutant selective PI3Kα inhibitor, validates PI3Kα as a therapeutic target. However, inhibition of wild-type PI3Kα leads to significant toxicity, including hyperglycemia and rash. RLY-2608, a novel, oral allosteric PI3Kα inhibitor, is designed to overcome these limitations via mutant- and isoform-selective PI3Kα inhibition for greater target coverage, improved tolerability, and anti-tumor activity. ReDiscover (NCT05216432) is the ongoing, first-in-human study to investigate the maximum tolerated dose (MTD), recommended phase 2 doses (RP2Ds), safety, pharmacokinetics (PK), pharmacodynamics (PD) and anti-tumor activity of RLY-2608 monotherapy in pts with PIK3CA-mutant advanced solid tumors; and of RLY-2608 plus fulvestrant with or without ribociclib in pts with PIK3CA-mutant, HR+, HER2– BC. To date RLY-2608 plus fulvestrant has completed dose escalation; 400 and 600 mg BID is being investigated in the combination regimens, based on safety, PK, PD, and anti-tumor activity. Methods: This global, multi-center, dose escalation/expansion study of RLY-2608 monotherapy includes adult pts with advanced solid tumors who are refractory or intolerant to, or have declined, standard therapy. RLY-2608 is also being investigated in combination with fulvestrant and in combination with fulvestrant and ribociclib, each in previously treated pts with HR+, HER2– advanced/metastatic BC. Eligibility criteria include presence of a PIK3CA mutation (blood or tumor) per local assessment, ECOG performance status 0–1, evaluable disease per RECIST 1.1, and no prior treatment with a PI3K pathway inhibitor. RLY-2608 is administered daily in 4-week cycles. Adverse events (AEs) per CTCAE v5, PK, biomarkers (pAKT, mutant ctDNA and insulin pathway markers) and anti-tumor activity are assessed serially. Dose escalation employs a Bayesian Optimal Interval design to identify the MTD. Following dose escalation, expansion cohorts are enrolling patients with select PIK3CA-mutated solid tumors for treatment with RLY-2608 monotherapy and patients with HR+, HER2– metastatic BC for treatment with RLY-2608 plus fulvestrant with or without ribociclib. Primary endpoints are MTD/RP2D and AE profile; key secondary endpoints are PIK3CA genotype in blood and tumor, PK, biomarkers, and overall response rate. All dose expansion cohorts in ReDiscover are now enrolling in the United States and Europe. Clinical trial information: NCT05216432 .

A phase 1, open-label, dose escalation and dose expansion study to evaluate the safety, tolerability, pharmacokinetics, and antitumor activity of PF-07799544 (ARRY-134) as a single agent and in combination with PF-07799933 BRAF dimer inhibitor, in participants 16 years and older with advanced solid tumors.

TPS3180 Background: The MAPK pathway plays a role in several key signaling and phosphorylation events that contribute to tumorigenesis. Inhibition of MEK, along with RAF kinases, has proven to be a successful transformative strategy for melanoma and other MAPK pathway-altered tumors. However, the duration of clinical benefit is limited by a narrow therapeutic index, de novo and acquired resistance and poor brain penetration. PF-07799544 is a next-generation, fully brain penetrant MEK inhibitor. PF-07799933 is an oral selective ATP-competitive small-molecule RAF kinase inhibitor that suppresses BRAF signaling in BRAF V600-mutant and non-V600-BRAF mutant tumors. It displays significantly less paradoxical activation than approved BRAFi and is not “pan RAF” as it spares non-BRAF mutated-containing RAF dimers. We describe here the design of the Phase 1 study of PF-07799544 as Monotherapy or in Combination with a next generation BRAF dimer inhibitor PF-07799933 in participants with BRAF mutated (BRAFm) advanced solid tumors. Methods: The purpose of this first-in-human study is to investigate the safety, tolerability, pharmacokinetics (PK), pharmacodynamics, and potential clinical benefits of PF-07799544 administered as a single agent in participants with advanced solid tumors (Phase 1a) and in combination with PF-07799933 in participants with BRAF Class 1, 2 and 3 mutated solid tumors with or without brain involvement (Phase 1b). Phase 1a will enroll participants with advanced solid tumors who have progressed on standard of care. The primary objective is to determine monotherapy MTD/RDE of PF-07799544. Once PK measurements indicate the potential for significant WT MEK mutation target coverage, participants with untreated and symptomatic brain metastases (bm) will be allowed to enroll. Phase 1b is comprised of multiple sub-studies, all of which evaluate PF-07799544 in combination with PF-07799933 in participants with BRAFm solid tumors who have progressed on standard of care therapies, including Class 1 BRAFi where indicated. Sub-study B: BRAFm melanoma (V600 and non-V600) will determine the MTDc/RDEc of the combination (Part 1 primary objective), followed by dose expansion cohorts (Part 2) (~80 participants): Cohort 1: BRAF V600 melanoma (asymptomatic and untreated bm permitted), Cohort 2: BRAF V600 melanoma (symptomatic bm), Cohort 3 BRAFm Class 2/3 melanoma (asymptomatic and untreated bm permitted); Sub-study C: BRAFm Class 2 or 3 advanced solid tumor Cohort 1 (asymptomatic and untreated bm permitted and Cohort 2 (symptomatic bm) (~20 each cohort). The main objectives of the dose expansion cohorts in all substudies, will be to evaluate anti-tumor activity, safety, PK and PD. Clinical trial information: NCT05538130 .