Post-baseline Tumor Assessment Research Articles

Abstract PO1-06-02: Solti-1716 TATEN phase II trial: Targeting non-Luminal disease by PAM50 with pembrolizumab and paclitaxel in Hormone Receptor-positive/HER2-negative advanced breast cancer (ABC)

Abstract Background Within HR+/HER2-negative breast cancer, PAM50 non-luminal tumors (HER2-enriched [HER2-E] and Basal-like) have higher expression of proliferation and immune-related genes and tumor infiltrating lymphocytes and might benefit from immunotherapy. Here, we report the efficacy, safety, and correlative analysis data of the TATEN trial, the first study designed to evaluate pembrolizumab and paclitaxel in HR+/HER2-negative, PAM50 non-luminal, ABC. Methods TATEN trial (NCT04251169) is a single-arm, multicenter, phase II study evaluating pembrolizumab in combination with paclitaxel in patients with HR+/HER2-, PAM50 non-luminal ABC. Key inclusion criteria include progression to prior CDK4/6 inhibitors (CDK4/6i), presence of measurable disease, no prior chemotherapy for ABC, ECOG 0-1, and non-luminal metastatic disease by PAM50. Included patients received pembrolizumab at 200 mg every 3 weeks (beginning at cycle 1) in combination with weekly paclitaxel at 80 mg/m2 beginning at cycle 2. The primary endpoint was overall response rate (ORR) according to RECIST V1.1. in patients who received at least one dose of combination treatment and had a first, post-baseline tumor assessment (evaluable population). Secondary endpoints included progression-free survival (PFS), clinical benefit rate (CBR), safety, and predictive biomarkers. The study was based on a Simon two-stage design. Stage I of the trial would be considered successful if at least 6 of 15 patients achieved a partial response and/or complete response. In that case, the trial would recruit up to 46 evaluable patients for a target ORR ≥ 41%. Metastatic biopsies from patients enrolled in pre-screening were also evaluated for tumor infiltrating lymphocytes (TILs) and were further analyzed with an expression panel of 192 genes, including PDL1 and PD1. Results From July 2020 to December 2021, 132 tumors were screened, and 27 PAM50 non-luminal tumors were identified (20%). Non-luminal tumors trended to have higher PDL1 expression (p=0.090) and TILs (p=0.084) compared to luminal tumors, while no difference was observed for PD1 (p=0.850). Of 20 recruited patients in the study (stage I+II), 18 were evaluable for the primary endpoint. Baseline characteristics were as follows: median age 55 years, ECOG 0 55%, de novo MBC 22%, and visceral disease 72.2%. Eleven patients had received paclitaxel treatment in the adjuvant setting. Regarding PAM50 subtype, 2 patients had basal-like and 16 HER2-E tumors. At the time of data cut-off (June 2023), 13 patients (72.2%) had stopped their treatment because of progressive disease and 3 (16.6%) due to toxicity. Two patients (11.1%) were still on treatment. The ORR was 61.1 % (11 of 18, 95% CI 35.7-82.7). CBR was 88.9% (16 of 18, 95% CI 65.3-98.6), and median PFS was 8.3 months (95% CI 7.3 – 14.1). Treatment-related adverse events (TRAEs) of any grade (G) occurred in 19 patients (95%), while 45% of patients experienced G3 TRAEs. No G4 or G5 TRAEs were reported in the evaluable population. Gene expression analysis was successful for all recruited patients (n=20). High expression of the PAM50 luminal A signature (p=0.049), and the luminal genes PGR (p=0.028) and RRAGA (p=0.038) were associated with worse PFS (univariate analyses). The pan-leucocyte receptor CD84 (p=0.028) was associated with better PFS (univariate analysis). Conclusions Pembrolizumab in combination with paclitaxel is safe and exhibits promising efficacy outcomes in patients with CDK4/6i resistant HR+/HER2- ABC with a PAM50 non-luminal subtype. Although meeting the criteria for stage II, the enrollment was stopped prematurely due to the lack of funding and pembrolizumab supply. More correlative analyses will be presented at the conference. This study was funded in part by MSD. Citation Format: Aleix Prat, Benedetta Conte, Fara Brasó-Maristany, Nuria Chic, Montserrat Muñoz, Cristina Hernando, Manuel Alva, Silvia Vazquez, Salvador Blanch, Mafalda Oliveira, Esther Fernández, Oleguer Castillo, Patricia Galván, Ángela Aguirre, Esther Sanfeliu, Lorea Villanueva, Tomás Pascual, Eva Ciruelos. Solti-1716 TATEN phase II trial: Targeting non-Luminal disease by PAM50 with pembrolizumab and paclitaxel in Hormone Receptor-positive/HER2-negative advanced breast cancer (ABC) [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-06-02.

Abstract PS17-08: A Phase Ib Study to Evaluate the Efficacy and Safety of Afuresertib Plus Fulvestrant in Patients with Locally Advanced or Metastatic HR+/HER2- Breast Cancer Who Failed Standard of Care Therapies

Abstract Background The combination of an aromatase inhibitor with a CDK4/6 inhibitor is the mainstay of first-line endocrine therapy (ET) for locally advanced or metastatic HR+/HER2− breast cancer (LA/mBC). Management of recurrent disease in the post-CDK4/6 inhibitor setting includes additional lines of ET single agent or in combination with a targeted agent. For patients with HR+/HER2− LA/mBC tumors, fulvestrant monotherapy as the second- or third-line therapy has limited activity with a median PFS of 1.9-3.6 months. Effective targeted treatments for these patients are needed to maintain quality of life, improve survival, and delay the initiation of cytotoxic chemotherapy. Methods This ongoing single arm, open-label global study (NCT04851613) is to evaluate the efficacy and safety of the combination therapy of afuresertib (a pan-AKT inhibitor) plus fulvestrant in patients with HR+/HER2− LA/mBC. Eligible patients must have received 1-2 prior lines of ET. Patients may have prior treatment of CDK4/6 inhibitors (up to 1 therapy), and/or up to 1 line of chemotherapy. Patients received afuresertib (125 mg PO, QD) in combination with fulvestrant (500 mg IM; Day 1 and 15 in Cycle 1, and Day 1 in subsequent 28-day cycles). The safety of the initial treatment doses of the combination therapy was evaluated in the first 6 patients during the Cycle 1 safety run-in period. Radiographic assessment per RECIST 1.1 was performed every 8 weeks for the first 6 cycles and every 12 weeks thereafter. The primary endpoint was the investigator-assessed objective response rate (ORR). The secondary endpoints included safety and tolerability of the combination therapy and pharmacokinetic characterization. Results Twenty patients (1 male and 19 females, 3 in the US and 17 in China) were enrolled between May 2022 and April 2023. As of the data cut-off date of May 26th, 2023, 10 patients had discontinued the study treatment (9 due to disease progression, 1 due to patient’s withdrawal of consent) and 10 patients were still in treatment. Of the 19 patients who had at least one post-baseline tumor assessment, 4 patients observed confirmed Partial Response (cPR), 12 had best overall response of Stable Disease, and 3 had Progressive Disease (PD). The Disease Control Rate is 84%. Of the 15 patients who had at least 2 tumor assessments or who discontinued treatment early due to PD, the confirmed ORR is 26.7% (4 cPR). No dose modification was required during the safety run-in. The most common treatment-emergent adverse events (TEAEs, > 20% of patients) of all grades were hyperglycemia (50%), diarrhea (45%), ALT/AST increase (40%), nausea (35%), rash (35%), hypercholesterolemia (35%), and anemia (30%), the majority of which were Grade 1. Grade 3 AEs were reported in 4 patients, including diarrhea (1 patient), WBC increase (1 patient), creatine phosphokinase increase (1 patient), and ALT/AST increase and rash (1 patient). No SAE or TEAE >= Grade 4 were reported. No patient discontinued treatment due to TEAE. Conclusions The preliminary data from the combination therapy of afuresertib plus fulvestrant has shown promising efficacy with a well-tolerated safety profile in patients with HR+/HER2− LA/mBC who progressed on 1-2 prior lines of standard of care therapies. These results support further evaluation of this combination therapy in this patient population in an upcoming phase III study. Citation Format: Binghe Xu, Pin Zhang, Tao Sun, Ying Wang, Zhongsheng Tong, Sneha Phadke, Trevor Feinstein, Pengfei Guo, Jing Qu, Xiaoyu Wang. A Phase Ib Study to Evaluate the Efficacy and Safety of Afuresertib Plus Fulvestrant in Patients with Locally Advanced or Metastatic HR+/HER2- Breast Cancer Who Failed Standard of Care Therapies [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PS17-08.

Abstract PO2-04-03: BL-M07D1, an antibody-drug conjugate directed to HER2 in patients with locally advanced or metastatic Breast Cancer with HER2-positive/low-expression and other solid tumors: Results from a first-in-human phase 1 study

Abstract Background: BL-M07D1 is an anti-HER2 antibody-drug conjugate (ADC) comprised of a humanized anti-HER2 antibody, a cathepsin B cleavable linker, and a novel topoisomerase I inhibitor (Ed-04). Methods: This study included subjects with locally advanced or metastatic HER2 expressing (positive/low) breast cancer (BC) and other solid tumors. BL-M07D1 would be administered at doses of 1.0mg/kg Day 1 & Day 8 every 3 weeks (D1D8 Q3W) or 2.6, 3.2, 3.8, 4.4, 5.0, 5.6, 6.2, 6.8 and 7.4 mg/kg Day 1 every 3 weeks (D1Q3W) during dose escalation (D-ESC). A subset of patients (pts) will be enrolled in the dose-expansion phase (D-EXP) at D1 Q3W regimens. Results: As of June 25, a total of 75 pts have been treated with at least one dose of BL-M07D1, with 22 pts in the D-ESC phase and 53 in the D-EXP phase. Among the 75 pts, 1 received 1.0 mg/kg D1D8Q3W and 74 were treated on the D1Q3W schedule. Dose-limiting toxicity (DLT) was observed at 6.2mg/kg (febrile neutropenia and G3 thrombocytopenia lasting >7 days in one patient). The maximum tolerated dose (MTD) has not been reached yet. D-EXP dose levels included 3.8, 4.4, 5.0 and 5.6mg/kg D1 Q3W. This study enrolled 62 patients with BC, 6 with gastric cancer, 4 with colorectal cancer and 3 with non-small cell lung cancer. The most common TEAEs ( >10%, all grade/≥G3) were leukopenia (79%/24%), neutropenia (69%/39%), anemia (63%/11%), nausea (47%/0%), thrombocytopenia (37%/9%), vomiting (37%/1%), decreased appetite (27%/0%), lymphopenia (24%/8%), alopecia (23%/0%), asthenia (19%/0), gamma-glutamyl transferase increased (17%/0%), aspartate aminotransferase increased (17%/0%), constipation (13%/0%), diarrhea (12%/0%), hypertriglyceridemia (12%/0%), urinary tract infection (11%/1%), COVID-19 (11%/0%), occult blood positive (11%/0%), pyrexia (11%/0%). No ILD was observed. Forty-five pts with BC were evaluated for efficacy (i.e., had at least one post-baseline tumor assessment). Updated efficacy and pharmacokinetic (PK) results will be presented at the meeting. Conclusions: BL-M07D1 demonstrated encouraging efficacy in heavily pretreated HER2 expressing cancers, especially in HER2+ BC. The safety profile showed adequate safety and tolerability. Clinical trial identification: NCT05461768. Efficacy in Patients with Breast Cancer a. 8/9 pts received prior HER2-ADC with microtubule inhibitor. 1/9 pts received prior HER2-ADC with TOPI inhibitor. b. 6 pts with tumor shrinkage are still on-going. c. All pts with tumor shrinkage are still on-going. Citation Format: Erwei Song, Herui Yao, Meili Sun, Hong Zong, Rongbo Lin, Wen Zou, Muran Ding, Jing Yu, Sa Xiao, Hongwei Wang, Hai Zhu, Martin Olivo, Yi Zhu. BL-M07D1, an antibody-drug conjugate directed to HER2 in patients with locally advanced or metastatic Breast Cancer with HER2-positive/low-expression and other solid tumors: Results from a first-in-human phase 1 study [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-04-03.

Abstract CT117: A phase 1 study of D3S-001, a second-generation GDP-bound KRAS G12C inhibitor, as monotherapy in patients with KRAS G12C-mutated solid tumors

Abstract Background: D3S-001 is a second-generation (2G) GDP-bound KRAS G12C inhibitor (G12Ci). Its high covalent potency and rapid target engagement kinetics correlated with robust anti-tumor activity preclinically and translated into promising clinical activity in a phase 1 first-in-human trial (FIH). Here we report clinical data from D3S-001 FIH trial (NCT05410145). Methods: D3S-001 was administered as monotherapy to patients (pts) with KRAS G12C mutated advanced solid tumors at 6 planned dose levels (50-900mg QD) from 3 countries. The key objectives were safety, PK, antitumor activity, and ctDNA kinetics. Results: As of 6 Feb 2024, a total of 41 pts (25 non-small cell lung cancer [NSCLC], 12 colorectal cancer [CRC] and 4 pancreatic cancer [PDAC]) were dosed. Median follow-up was 5.1 months (m, range 0.2-15.4m) and 28 pts (68.3%) remain on-study treatment. No treatment-related DLT or deaths were observed. Treatment-related AEs (TRAE) of any grade occurred in 30 pts (73.2%). Of which, 6 (14.6%) were Grade 3 (no Grade 4 or higher). D3S-001 dose was modified in 11 pts (26.8%) due to TRAE, and no pts had dose discontinuation due to TRAE. PK analysis indicates dose/exposure linearity and terminal plasma T1/2 of ~11 hours. Of 37 pts with post-baseline tumor assessments, 33 were naïve to G12Ci and 4 were G12Ci pre-treated. In 33 G12Ci naïve pts, PRs were achieved in 25/33 overall population (75.8%, 95% CI 57.7, 88.9%), in 14/20 NSCLC pts (70.0%, 95% CI 45.7, 87.2%), in 7/9 CRC pts (77.8%, 95% CI 40.2, 96.1%), and in 4/4 PDAC pts (100.0%, 95%CI 39.6, 100.0%). CNS efficacy was observed in 2/6 NSCLC pts. Of all G12Ci naive pts (n=36), 6-month PFS rate is 69.1% (95% CI 46.3, 83.7%), but median PFS and DoR are not yet mature. Deeper tumor reductions were observed in 5 out of 9 G12Ci naïve pts after intra-subject dose escalation. All 4 G12Ci pre-treated pts (2 NSCLC, 2 CRC) showed stable disease at the first post-baseline assessment. Serial assessment of ctDNA showed significant declines in G12C VAF as early as on Day 8 of treatment. 600mg QD was selected as RP2D. Conclusions: D3S-001, a 2G G12Ci, is well tolerated and delivers promising anti-tumor activity in pts with NSCLC, CRC, and PDAC carrying KRAS G12C mutation across all dose levels in FIH trial. Citation Format: Byoung Chul Cho, Shun Lu, Myung Ah Lee, Zhengbo Song, John Park, Sun Min Lim, Ziming Li, Jun Zhao, Gary Richardson, Yanqiao Zhang, Jun Zhang, Anwen Liu, Cheng Chen, Jia Wang, Jingtao Lu, Haopeng Rui, Qian Chen, Hui Wang, Jing Zhang, Zhi Jian Chen, Tony Mok. A phase 1 study of D3S-001, a second-generation GDP-bound KRAS G12C inhibitor, as monotherapy in patients with KRAS G12C-mutated solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT117.

Abstract CT179: Safety and efficacy of JSKN003 in patients with advanced/metastatic solid tumors: A first-in-human, dose-escalation, multicenter, open-label, phase I study

Abstract Background: JSKN003 is a bispecific HER2-directed antibody-drug conjugate (ADC) conjugated to a topoisomerase I inhibitor (TOP1i) via a dibenzocyclooctyne tetrapeptide linker on the glycan of a humanized bispecific antibody. Pre-clinical studies showed that JSKN003 had a good serum stability and strong anti-tumor activity. Hence JSKN003 could be effective in HER2 expressing tumors with a potentially broader therapeutic window. Methods: JSKN003-101 is a first-in-human, dose-escalation and -expansion study in Australian patients (pts) with advanced/metastatic solid tumors. Pts (ECOG PS 0-1) with histologically documented HER2-expressing (IHC ≥ 1+) or pts with HER2-mutant cancers who failed prior systemic therapies were recruited and received JSKN003 monotherapy intravenously Q3W. The objectives were safety, tolerability, maximum tolerated dose (MTD) or recommended phase 2 dose (RP2D), pharmacokinetics (PK), and preliminary antitumor activity. Here the results from dose-escalation part were reported. Results: As of 15th December 2023, 32 pts (15 breast cancers, 5 ovarian cancers, 3 bladder cancers, 2 esophageal cancers, 2 non-small cell lung cancers, 1 gastric cancer, 1 head and neck cancer, and 3 other cancers) were enrolled and received JSKN003 across 7 dose levels (1.0, 2.1, 4.2, 5.2, 6.3, 7.3, and 8.4 mg/kg, Q3W). Among the 32 pts, 9 were IHC 1+, 16 were IHC 2+, and 7 were IHC 3+. Most pts (22/32, 68.8%) received ≥ 3 prior lines of therapy. The median duration of treatment was 15.8 (range, 6-54) weeks, and 19 pts (59.4%) remain on treatment. Treatment-related adverse events (TRAEs) occurred in 27 pts (84.4%) and 2 pts (6.3%) in 4.2mg/kg and 7.3mg/kg experienced grade 3 TRAE (anemia and fatigue); the most common TRAEs were diarrhea (62.5%) and nausea (50.0%),which were all grade 1-2. Only 1 pt experienced interstitial lung disease (7.3mg/kg, Grade 2). To date, no DLT events were found yet, and no TRAE led to death or treatment discontinuation. MTD has not been reached in 8.4 mg/kg.Following a single dose, exposures (Cmax and AUC) of JSKN003 and released TOP1i increased proportionally over a dose range of 4.2 mg/kg to 8.4 mg/kg. T1/2 of JSKN003 is approximately 5-6 days for 6.3 mg/kg and higher doses and increases with dose escalation. Accumulation of JSKN003 was minimal within the range of 1.1-1.5. The exposure of released payload was significantly lower than JSKN003 ADC, demonstrating the stability of the JSKN003 in circulation. All pts had at least one post-baseline tumor assessment. 16 pts achieved partial response as per RECIST 1.1 by investigator. The objective response rate (ORR) and disease control rate (DCR) was 50.0% (95%CI: 31.9%, 68.1%) and 90.6% (95%CI: 75.0%, 98.0%), respectively. The ORR in pts with IHC 1+, 2+ and 3+ was 55.6% (5/9), 37.5% (6/16), and 71.4% (5/7), respectively. As for the efficacy of the HER2+ BC and HER2-low BC, the ORR was 80% (4/5) and 40.0% (4/10), respectively. Conclusions: JSKN003 was well tolerated with encouraging preliminary antitumor activity in heavily pretreated pts with advanced/metastatic solid tumors, especially in pts with HER2 amplified tumors. As of the cut-off date, no DLT was observed, MTD has not been reached yet. Clinical trial information: NCT05494918 Citation Format: Claire Beecroft, Bo Gao, John Park, Kate Wilkinson, Karl Zhang, Xiangyun Yan, Yuan Lv. Safety and efficacy of JSKN003 in patients with advanced/metastatic solid tumors: A first-in-human, dose-escalation, multicenter, open-label, phase I study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT179.

Abstract 2395: Camrelizumab combined with apatinib and hepatic artery infusion chemotherapy (HAIC) as conversion therapy for patients with unresectable hepatocellular carcinoma(HCC): A single-arm exploratory clinical study

Abstract Background: There is still no standard treatment recommendation for hepatocellular carcinoma transformation therapy, and researches are still under exploration. Methods: This study was a single-arm phase II trial, eligible patients had histologically or cytologically confirmed unresectable HCC, without extrahepatic metastases and multiple diffuse liver lesions. Patients received camrelizumab and apatinib combined with HAIC for 2-8 cycles followed by surgery after evaluation. Primary endpoints were radiographic assessment of conversion rate and radical (R0) resection rate. Secondary endpoints were pathologic complete response rate (pCR), objective response rate (ORR) by modified RECIST (mRECIST) and RECIST version 1.1(RECIST v1.1) and safety. Results: Between March 17, 2021 and July 28, 2023, 22 patients were enrolled, including 9 (40.9%) patients with BCLC stage A, 2 (9.1%) patient with B, and 11 (50%) patients with C, 9 (40.9%) patients had tumor thrombus. Patients received treatment of a median of 2 cycles (range: 1-6 cycles). All 22 patients were included in thte safety set, before the first scheduled post-baseline tumor assessment, one patient changed treatment plan because of live function damage, three patients were failed to return to hospital for treatment because of civid-19. At the data cut off on 23 November, All other 18 patients conducted at least one efficacy evaluation, 8(44.4%) of 18 patients had an objective response and 16(88.9%) had disease control according to RECISIT v1.1, 3(16.7%) had a complete response, 9(40.9%) had a partial response and 18(88.9%) had disease control according to m RECIST. 15(68.2%) of 22 patients could undergo surgical resection based on imaging evaluation. 7 patients failed to undergo surgery due to CR (3patients), abnormal liver function(1 patient), immune myocarditis(1 patient), patient rejection(1 patient) waiting for surgery(1 patient). Resection was completed in 8 (44.4%) patients, and the R0 resection rate was 100%. The pCR rate in the surgery population was 25%, and the MPR rate is 37.5%. The most common grade 3 adverse events were increased alanine aminotransferase (36.3%) and decreased lymphocyte count (36.3%). A case of grade 4 immune-associated myocarditis occurred. No grade 5 treatment-related toxicity occurred. Conclusion: Camrelizumab combined with apatinib and HAIC showed promising activity and manageable toxicity, and might be a potential conversion treatment option for patients with unresectable HCC. Citation Format: Lei Zhao, Bo Zhang, Xuetao Shi, Kai Cui, Jianxin Zhang, Jingtao Zhong, Zhongchao Li, Pengfei Sun, Chengsheng Zhang, Lei Li. Camrelizumab combined with apatinib and hepatic artery infusion chemotherapy (HAIC) as conversion therapy for patients with unresectable hepatocellular carcinoma(HCC): A single-arm exploratory clinical study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2395.

A phase Ib/II study of ASKB589 (anti-Claudin 18.2 [CLDN18.2] monoclonal antibody) combined with CAPOX and PD-1 inhibitor as first-line treatment for locally advanced, relapsed and metastatic gastric/gastro-esophageal junction (G/GEJ) adenocarcinoma.

317 Background: ASKB589 is a humanized IgG1 monoclonal antibody against Claudin 18.2 (CLDN18.2) with high affinity and enhanced antibody-dependent cytotoxicity. We report preliminary safety and efficacy data from an ongoing Phase Ib/II, dose-escalation and expansion study of ASKB589 combined with capecitabine, oxaliplatin(CAPOX) and Sintilimab as first-line treatment of G/GEJ adenocarcinoma (NCT05632939). Methods: The study enrolled G/GEJ adenocarcinoma patients(pts) with CLDN18.2 positive expression. The dose-escalation phase used a 3 + 3 design to determine the maximum tolerated dose (MTD). In expansion, the dose of ASKB589 selected for expansion was based on the safety, tolerability, pharmacokinetics and antitumor activity during escalation phase. Responses were assessed by RECIST 1.1 every 2 cycles (6 weeks). Adverse events (AEs) were graded using CTCAE v5.0. In escalation, pts received ASKB589 intravenously (IV) at doses of 6 mg/kg (n = 3) and 10 mg/kg (n = 6) every 3 weeks (Q3W) combined with CAPOX and Sintilimab. In expansion, all pts received ASKB589 IV at a dose of 6 mg/kg. Results: As of July 20, 2023, 9 pts were enrolled in escalation. No DLT was observed and thus the MTD was not identified. 9(100%)pts had treatment-related adverse events (TRAEs), the most common being nausea (77.8%), hypoproteinemia (66.7%), and hyponatremia (55.6%). While the majority of TRAEs were grade 1 or 2, 1 pt (11.1%) had a grade 3 TRAE (decreased neutrophils [10mg/kg]). In expansion, 26 pts with CLDN18.2 moderate-to-high expression (≥2+ membrane staining intensity in ≥40% of tumor cells) were included in the safety set. 24(92.3%) pts had TRAEs, the most common being nausea (65.4%), vomiting (53.8%), hypoproteinemia (53.8%), anemia (50.0%), fatigue (26.9%) and decreased neutrophils (23.1%). 3 pts (11.5%) had TRAEs of grade ≥3 including hypocalcemia, hypokalemia, decreased neutrophils, fatigue and bone marrow suppression. For the 15 evaluable pts who had at least one post-baseline tumor assessment, 12 pts (80.0%) achieved PR for an unconfirmed objective response rate (ORR) of 80.0%. 3 pts (20.0%) had SD for a disease control rate (DCR) of 100.0%. The PK of ASKB589 at doses of 6mg/kg and 10mg/kg combined with CAPOX and anti-PD1 therapy was consistent with that of monotherapy. Conclusions: ASKB589 combined with CAPOX and PD-1 inhibitor has manageable safety and promising antitumor activity. 6mg/kg is chosen as the recommended dose in subsequent studies. Clinical trial information: NCT05632939 .

Subcutaneous Mosunetuzumab Is Active and Has a Manageable Safety Profile in Patients with Previously Untreated, Low-Tumor Burden Follicular Lymphoma: Initial Results from the Phase II Morningsun Study

Background: Mosunetuzumab is a CD20xCD3 bispecific antibody that is approved for the intravenous (IV) treatment of patients with relapsed/refractory (R/R) follicular lymphoma (FL) who have received at least two prior lines of systemic therapy, and is suitable for administration in the outpatient setting. In an ongoing Phase I/II study (NCT02500407), IV mosunetuzumab induced durable responses and had a manageable safety profile in patients with heavily pre-treated R/R indolent and aggressive B-cell non-Hodgkin lymphomas (NHL) when administered as a fixed-duration treatment (Budde et al. J Clin Oncol 2022). Subcutaneous (SC) dosing was also evaluated and showed similar efficacy to IV dosing and a manageable safety profile (Budde et al. ASH 2022). MorningSun (NCT05207670) is an ongoing, open-label, multicenter, Phase II study evaluating the efficacy, safety and pharmacokinetics of SC mosunetuzumab in patients with selected B-cell NHLs, including those without prior treatment (Flinn et al. ASCO 2022). For the first time, we present initial efficacy and safety data for patients with previously untreated, low-tumor burden FL who were enrolled into MorningSun at community and academic centers in the United States. Methods: Inclusion criteria include previously untreated Grade (Gr) 1 or 2 FL, low tumor burden by GELF criteria, Ann Arbor stage III or IV disease, and ECOG performance status 0-2. Mosunetuzumab is administered without mandatory hospitalization by SC injection in 21-day cycles. In Cycle (C) 1, mosunetuzumab is given on Day (D) 1 (5mg), D8 (45mg) and D15 (45mg). In C2+, mosunetuzumab is given on D1 only (45mg). Treatment is continued for up to 17 cycles (~1 year). Patients who are in complete metabolic response (CMR) at C8 can discontinue active treatment and enter long-term follow-up. Premedication with dexamethasone (20mg) is mandatory in C1 and C2 and optional thereafter. Acetaminophen and diphenhydramine may also be given. The primary endpoint is the rate of progression-free survival at 24 months. Results: At data cut-off (March 6, 2023), 30 patients had been enrolled (19 at community centers and 11 at academic centers). Median age was 56 years. All patients had ECOG performance status 0-1, and a minority had B symptoms ( Table 1). The median duration of follow-up was 4.2 months (range: 0.2-11.1) and the median number of cycles received was 7 (range: 1-13). Among 24 patients who had at least one post-baseline tumor assessment, 23 achieved an objective response (95.8%; 95% CI: 78.9-99.9), including 20 who achieved a CMR (83.3%; 95% CI: 62.6-95.3). All responses were observed at the first post-baseline tumor assessment in C4 (median time to response: 2.6 months; 95% CI: 2.6-2.8). At cut-off, responses were ongoing in all patients who achieved CMR and 2 of 3 patients who achieved partial metabolic response. The most common adverse event (AE) was injection site reaction (53.3% of patients), all of which were Gr 1 (43.3%) or Gr 2 (10.0%). Cytokine release syndrome (CRS) occurred in 43.3%. Most patients had Gr 1 CRS ( Table 2). No Gr ≥3 CRS events or discontinuations due to CRS were reported. CRS occurred in C1 only. All CRS events resolved. Other common (>20%) AEs were headache (50.0%), nausea (30.0%), fatigue (26.7%), pyrexia (23.3%), chills (23.3%) and alanine aminotransferase increased (23.3%). Gr ≥3 AEs in ≥5% of patients were neutrophil count decreased (2 patients; 6.7%). Serious AEs (SAEs) in ≥5% were CRS (2 patients; 6.7%). No SAEs of infection were reported. AEs potentially consistent with immune effector cell-associated neurotoxicity syndrome (ICANS) occurred in 2 patients (Gr 1 confusional state and Gr 1 memory impairment in one patient each); both events resolved. No mosunetuzumab-related AEs leading to discontinuation occurred and no Gr 5 (fatal) AEs were reported. Conclusions: Initial MorningSun data support that SC mosunetuzumab is active in patients with previously untreated, low-tumor burden FL. Safety data demonstrate a manageable safety profile that is consistent with that seen in patients with R/R B-cell NHLs and is supportive of outpatient administration.

Efficacy and Safety of Golcadomide, a Novel Cereblon E3 Ligase Modulator (CELMoD) Agent, Combined with Rituximab in a Phase 1/2 Open-Label Study of Patients with Relapsed/Refractory Non-Hodgkin Lymphoma

Introduction: Golcadomide is a novel, oral, small-molecule CELMoD ® agent that co-opts cereblon to induce targeted degradation of the transcription factors Ikaros/Aiolos, which are crucial to B-cell malignancy development. We previously reported promising efficacy with a predictable and manageable safety profile of golcadomide in patients with relapsed/refractory (R/R) non-Hodgkin lymphoma (Michot et al. ICML 2023, presentation #90). Methods: CC-99282-NHL-001 (NCT03930953) is a 2-part, multicenter, first-in-human study with dose escalation (Part A) of golcadomide monotherapy and expansion (Part B) ± combination partners. Patients with R/R diffuse large B-cell lymphoma (DLBCL) or R/R follicular lymphoma and disease progression after ≥ 2 lines of therapy or transplant-ineligible patients with R/R DLBCL after ≥ 1 line of therapy were included. Following dose exploration in Part A, golcadomide was administered at 0.2 or 0.4 mg alone or with rituximab on 2 intermittent schedules in Part B. Total duration of treatment is up to 2 years. Here, we report efficacy and safety results for golcadomide + rituximab in patients with DLBCL treated in Part B expansion on a 14 days on/14 days off schedule. The efficacy-evaluable population consisted of patients completing ≥ 1 cycle of golcadomide (taking ≥ 75% of assigned doses) and having baseline and ≥ 1 post-baseline tumor assessment. Results: As of May 10, 2023, 35 patients with DLBCL were enrolled and 34 received ≥ 1 dose of golcadomide or rituximab (safety population); 17 (49%) patients were ongoing and 17 (49%) had discontinued treatment, mostly due to progressive disease (n = 10, 29%). The median age was 60 years (range, 35-80). The median number of prior anticancer therapies was 4.5 (range, 1-11); 68% (n/N = 23/34) of patients had prior CAR T-cell therapy and 49% (n/N = 17/35) were refractory to their last regimen. Golcadomide median treatment duration was 8 weeks (range, 4-48) and median follow up was 15 weeks (range, 2-55). In the efficacy-evaluable population (n = 16), overall response rate (complete response [CR] + partial response) was 50% (n = 8), with CR occurring in 13% (n = 2) of patients. Median duration of response was 17.4 weeks (range, 7.4-45.9). Response data in the 0.2-mg and 0.4-mg golcadomide-treated groups are shown in the table. In the safety population (n = 34), neutropenia was the most common any-grade treatment-emergent adverse event (TEAE), occurring in 15 (44%) patients, all of which were grade 3/4. No febrile neutropenia occurred. The most common treatment-related adverse event (TRAE) for golcadomide was neutropenia (all grade 3/4), occurring in 14 (41%) patients, comprising 5/19 (26%) patients treated at the 0.2-mg and 9/15 (60%) patients treated at the 0.4-mg dose level. Granulocyte colony-stimulating factors were used in 14 (41%) patients. Six serious TRAEs related to golcadomide were reported (n = 1 each), all in the 0.4-mg group. One grade 5 TEAE occurred (tubulo-interstitial nephritis in the 0.2-mg group), which was reported to be due to progressive disease and considered unrelated to study treatment. TEAEs led to golcadomide discontinuation in 2 (6%) patients (1 at each dose level) and rituximab discontinuation in 5 (15%) patients. Similar pharmacokinetic (PK) exposures of golcadomide were observed when golcadomide was dosed alone and in combination with rituximab, indicating no apparent impact of rituximab on golcadomide PK. Analysis of circulating tumor DNA data is underway and will be presented. Conclusions: Golcadomide oral therapy combined with rituximab showed promising efficacy in heavily pretreated patients with R/R DLBCL, including 1 durable response over 300 days. Golcadomide can be safely combined with rituximab, and the combination showed a safety profile similar to that previously reported for golcadomide monotherapy. This study is ongoing, with continued enrolment in the monotherapy and golcadomide + rituximab combination expansion cohorts.

Multicenter phase I dose escalation and expansion study of pyrotinib in combination with camrelizumab and chemotherapy as first-line treatment for HER2-positive advanced gastric and gastroesophageal junction adenocarcinoma

Pembrolizumab plus trastuzumab and chemotherapy showed remarkable efficacy as first-line therapy for advanced HER2-positive gastric cancer. Pyrotinib is an irreversible pan-HER inhibitor. This single-arm, open-label phase 1 dose-escalation (1a) and expansion (1b) study investigated camrelizumab, an anti-PD-1 antibody, plus pyrotinib and chemotherapy as first-line treatment for advanced HER2-positive gastric and gastroesophageal junction (G/GEJ) adenocarcinoma. Between June 2020 and June 2022, 41 patients with previously untreated HER2-positive locally advanced unresectable or metastatic G/GEJ adenocarcinoma were enrolled. In phase 1a, patients underwent a 3+3 escalating dose design, receiving oral pyrotinib (240mg, 320mg, or 400mg daily), intravenous camrelizumab (200mg), and CapeOX (oxaliplatin 130mg/m2 on day 1 and capecitabine 1000mg/m2 twice daily for two weeks) every 3 weeks until progression, intolerable toxicity or consent withdrawal. The recommended phase 2 dose (RP2D) of pyrotinib was determined and used in the phase 1b. The primary endpoints were the safety, maximum tolerated dose (MTD), RP2D, and confirmed objective response rate (ORR). This trial was registered with chictr.org, number ChiCTR2000029717. Among 41 patients, 10 were in phase 1a (3at 240mg, 3at 400mg, and 4at 320mg due to one patient withdrawing consent), and 31 were in phase 1b. In phase 1a, the MTD of pyrotinib was 320mg daily due to dose-limiting toxicities (diarrhea [n=3] and vomiting [n=1]) observed at 400mg. Based on all available data, the RP2D of pyrotinib was set at 320mg. Among 41 patients, 20 patients (48.8%) developed grade ≥3 treatment-emergent adverse events (TEAEs), and four patients (9.8%) had any grade serious adverse events. No deaths occurred due to TEAEs. Among 27 patients who received the RP2D of pyrotinib and had a post-baseline tumor assessment, two patients (7.4%) achieved a confirmed complete response, and 19 patients (70.4%) achieved a confirmed partial response, resulting in a confirmed ORR of 77.8% (95% CI: 57.7-91.4). Pyrotinib plus camrelizumab and chemotherapy showed promising efficacy in the first-line treatment of advanced HER2-positive G/GEJ cancer. The safety profile was consistent with known toxicities of the agents, and no new or unexpected safety signals were identified. This study was funded by the Beijing Xisike Clinical Oncology Research Foundation (Y-HR2019-0377).

Results from two phase II studies of SI-B001, an EGFR×HER3 bispecific antibody, with/without chemotherapy in patients (pts) with recurrent and metastatic head and neck squamous cell carcinoma (HNSCC).

6037 Background: SI-B001 is an EGFR×HER3 bispecific antibody. We present the efficacy and safety results from two ongoing studies of SI-B001, S209 and S206, in recurrent and metastatic HNSCC. Methods: S209 included pts with recurrent and metastatic HNSCC progressed on prior anti-PD-1/L1 plus platinum-based chemotherapy (PBC). Pts were treated with SI-B001 16mg/kg IV QW. S206 included pts with recurrent and metastatic HNSCC progressed on prior anti-PD-1/L1 with or without PBC and received no more than two lines of treatment. Pts enrolled in S206 were divided into two groups: Group A, pts without prior exposure to paclitaxel were treated with SI-B001 (12mg/kg IV QW) plus paclitaxel (80mg/m2 IV QW); Group B, pts with prior exposure to paclitaxel were treated with SI-B001 (12mg/kg IV QW) plus docetaxel (35mg/m2 IV D1D8D15 Q4W). The study endpoints of the two studies were identical. The primary endpoint was objective response rate (ORR) by investigator per RECIST v1.1. Secondary endpoints were ORR by independent central review, progression-free survival (PFS), disease control rate (DCR), duration of response (DOR), overall Survival (OS), and safety. Results: As of Dec 31, 2022, 11 pts in S209 received SI-B001. Pts had a median of 4 prior lines of therapy. In 9 out of 11 pts who have at least 1 post baseline tumor assessment in S209, ORR (n/N) was 22.2% (2/9), mPFS [95%CI] was 2.7 [1.8-7.9] mo. 29 pts in S206 received SI-B001 plus chemotherapy, including 19 pts in Group A and 10 pts in Group B. In 22 pts who had at least 1 post baseline tumor assessment, ORR was 45.5% (10/22), mPFS was 5.1 [3.7-5.6] mo. 1 nasal sinus cancer pt enrolled had stable disease (SD). 14 out of the 18 pts who have at least 1 post baseline tumor assessment in Group A, ORR was 64.3% (9/14) mPFS was 5.6 [5.1-6.3] mo. 8 out of 10 pts who have at least 1 post baseline tumor assessment in Group B, ORR was 12.5% (1/8), mPFS was 1.9 [1.2-3.7] mo. The most common grade 3 and above treatment-related adverse events (TRAEs) in S209 was Hypomagnesaemia (9%). The most common grade 3+ TRAEs in S206 were rash (16%), anaemia (8%) and white blood cell count decreased (8%). No SI-B001 drug-related deaths occurred in either study. Conclusions: SI-B001 plus paclitaxel demonstrated potential improvements in ORR and DCR compared with SI-B001 monotherapy in recurrent and metastatic HNSCC. The toxicity of SI-B001 plus chemotherapy in HNSCC is manageable and tolerable. Clinical trial information: NCT05044897 ; NCT05054439 . [Table: see text]

A multicenter, single-arm phase 2 study of surufatinib plus toripalimab for patients with locally advanced or metastatic radioactive iodine-refractory differentiated thyroid cancer.

6089 Background: For patients (pts) with radioactive iodine–refractory differentiated thyroid cancer (RAIR-DTC), there presents a considerable therapeutic challenge with poor long-term outcomes. The open-label, multi-cohort, single-arm phase 2 study was performed to evaluate surufatinib (a small-molecule inhibitor of VEGFR 1-3, FGFR1 and CSF-1R) in combination with toripalimab (an anti-PD-1 antibody) in pts with RAIR-DTC. Methods: Eligible pts were with locally advanced or metastatic RAIR-DTC who were not amenable for surgery or external beam radiotherapy, with a radiologically confirmed disease progression within 12 months before treatment, and with ≥6 months since last radioiodine treatment. Enrolled pts received surufatinib 250 mg orally, QD, plus toripalimab 240 mg IV, Q3W, until disease progression or reaching the maximum treatment duration with toripalimab of 24 months, or other protocol-specified criteria. The primary endpoint was objective response rate (ORR) per RECIST 1.1. Results: From March 2020 to November 2021, 15 pts were enrolled and received a median duration of 11.1 months of the combination treatment, with a median age of 61 years (range: 37-74). 9 (60%) pts were male, and 12 (80%) had papillary thyroid cancer. Of the 13 pts with PD-L1 immunochemical results, 6 pts had PD-L1 CPS ≥1%. As of 28 Dec 2022, the median follow-up duration was 22.11 months. Of the 15 pts with at least one post-baseline tumor assessment, the confirmed ORR was 33.3% (5 PRs) and DCR was 93.3%. mDoR was 8.34 months. mPFS (95%CI) was 10.91 months (4.01, NA). mOS was not reached, and 12-month OS rate was 100%. 14 (93.3%) pts had treatment-emergent adverse events (TEAEs), and 10 (66.7%) pts reported grade ≥3 TEAEs, most commonly (≥10% pts) with hypocalcemia (20%), diarrhea (20%) and hypertension (13%). There was no death due to TEAE in the study. Conclusions: Surufatinib plus toripalimab showed encouraging antitumor activity and tolerable safety profile in pts with locally advanced or metastatic RAIR-DTC. Clinical trial information: NCT04169672 .

Venous infusion chemotherapy (VIC) combined with apatinib and camrelizumab for hepatocellular carcinoma (HCC) in CNLC stage III: A prospective, single-arm, phase II trial.

e16166 Background: The combination of anti-angiogenesis and immune checkpoint blockade showed promising outcomes for advanced HCC. Hepatic artery infusion chemotherapy (HAIC) combined with apatinib and camrelizumab could augment treatment efficacy in preliminary study. But HAIC had disadvantages such as technical limitations, expensive cost and poor patient comfort. In the present study, we aimed to investigate the efficacy and safety profile of VIC with apatinib and camrelizumab for CNLC stage Ⅲ HCC. Methods: This single-arm, phase II study enrolled treatment-naive adult (18 years) patients(pts) with CNLC stage Ⅲ and Child-Pugh score small or equal to 7 points (NCT05412589). Eligible pts received VIC (oxaliplatin 85 mg/ m2, leucovorin 200 mg/m2, 5-fluorouracil bolus 400 mg/m2 on day 1, and 5-fluorouracil infusion 2400 mg/m2 for 46 hours; q3w; 6 cycles), combined with apatinib (250 mg qd) and camrelizumab (200 mg q3w). The primary endpoint was objective response rate (ORR) per RECIST 1.1. Following an optimal Simon 2-stage design, 15 eligible pts needed to be included in the 1st stage, of whom at least 9 pts had to achieve objective responses to warrant further investigation in the second stage. Secondary endpoints were progression-free survival (PFS) rate at 6 months, PFS, overall survival (OS) per RECIST v1.1 or mRECIST, and safety. Results: At the data cut-off date (Jan. 31,2023), 17 pts were enrolled from Apr. 25, 2021, to Oct. 30, 2022 (1 woman and 16 men; median age, 48 years; 16 had HBV infection). The median tumor size was 87 mm. 11 (64.7%) pts had more than 3 tumors. 8 (47%) pts had main portal trunk invasion (Vp4). 7 (41.2%) pts had distant metastasis. The median follow-up was 8.17 months and all pts had at least one post-baseline tumor assessment. The confirmed ORR was 58.8% with 10 partial responses (PR) per RECIST v1.1, which met the threshold for expanding enrollment, while 70.6% per mRECIST. Among them, 11 (64.7%) pts received operation successfully and 5 (29.4%) pts reached pathological complete response (pCR). Notably, four pCR pts had Vp4 before the trial. The disease control rate was 94.11% whether per RECIST v1.1 or mRECIST. The median time to response was 2.27 months (interquartile range (IQR), 1.29-2.56) per RECIST v1.1 or 1.57 months (IQR, 1.17-2.32) per mRECIST. The estimated 6-month PFS rate was 76.4% per RECIST v1.1. The 6-month OS rate were 100%. Grade 3-4 treatment-related adverse events (AEs) occurred in 56.2% of pts, of which the most common were decreased neutrophils (38.5%), diarrhea (23.9%), thrombocytopenia (25.9%), and hypertension (11.1%). All AEs were expected and manageable, and no treatment-related deaths were reported. Conclusions: The triplet treatment of VIC plus camrelizumab and apatinib showed promising antitumor activity and acceptable safety for CNLC stage Ⅲ HCC, especially in those with main portal trunk invasion. Clinical trial information: NCT05412589 .

A multicenter, single-arm, phase 2 study of surufatinib plus toripalimab for patients with advanced endometrial cancer.

5609 Background: Several immunotherapy monotherapies, or combined with antiangiogenic inhibitors, have shown antitumor efficacy in endometrial cancer (EMC) and been approved by FDA. However, therapeutic options for EMC after failure of first-line treatment remain scarce in China. The open-label, multi-cohort, single-arm phase 2 study was performed to evaluate the efficacy and safety of the combination of surufatinib (a small-molecule inhibitor of VEGFR 1-3, FGFR1 and CSF-1R) with toripalimab (an anti-PD-1 antibody) for Chinese patients (pts) with EMC after failure of one or more prior lines of systemic treatment. Methods: Pts with EMC who progressed or were intolerable after at least one prior line of systemic antitumor therapy were eligible and enrolled. They received 21-day cycles of surufatinib 250 mg orally, QD, plus toripalimab 240 mg IV, Q3W, until disease progression or reaching the maximum treatment duration with toripalimab of 24 months, or other protocol-specified criteria. The primary endpoint was objective response rate (ORR) per RECIST 1.1. Results: From August 2020 to March 2022, 28 pts were enrolled and received the combination treatment (median duration: 4.6 months). Median age was 58 years (range: 50-71), and 22 (78.6%) pts were endometrioid adenocarcinoma at diagnosis. 9 (32.1%) pts had received ≥2 prior lines of therapy. As of 28 Dec 2022, the median follow-up duration was 16.8 months. Microsatellite status was available in 25 pts. 20 with mismatch repair-proficient (pMMR) and 5 with mismatch repair-deficient (dMMR) were determined. All 28 pts were evaluable with at least one post-baseline tumor assessment. Efficacy results were: confirmed ORR, 28.6% (8 partial response [PRs]); DCR, 82.1%; mDoR, 5.7 months; mPFS (95%CI), 5.4 months (2.7, 8.3); 12-month OS rate, 71.0%. Among pts with pMMR, the confirmed ORR was 25.0%; DCR was 85.0%; mDoR was 4.2 months; mPFS (95%CI) was 4.0 months (2.7, 8.3); 12-month OS rate was 75.4%. All pts experienced at least one treatment-emergent adverse event (TEAE), and 19 (67.9%) of them reported grade ≥3 TEAEs. The most common (≥5% pts) grade ≥3 TEAEs were hypertension (28.6%), aspartate aminotransferase increased (14.3%), alanine aminotransferase increased (10.7%), proteinuria (7.1%), Gamma-glutamyltransferase increased (7.1%) and malignant neoplasm progression (7.1%). No new safety signals were observed. Conclusions: Surufatinib plus toripalimab had a promising antitumor activity and a manageable safety profile in pts with EMC after failure of one or more prior lines of systemic therapy. Clinical trial information: NCT04169672 .

A phase Ib/II study of GFH018 in combination with toripalimab in recurrent/metastatic nasopharyngeal carcinoma (R/M NPC).

6026 Background: The transformed growth factor beta (TGF-β) signaling pathway is dysregulated in carcinogenesis. In NPC patients, upregulation of TGF-β pathway is correlated with disease stage or phenotype due to Epstein-Barr virus (EBV) infection. GFH018, a novel TGF-βRI inhibitor, can inhibit tumor growth through inhibiting the activity of TGF-βRI kinase to block the signal transduction of TGF-β and modulate the tumor immune microenvironment. Preclinical studies showed that GFH018 in combination with PD-1/PD-L1 monoclonal antibody can significantly inhibit tumor growth synergistically. Here we report the preliminary results of combining GFH018 and Toripalimab treating R/M NPC patients (pts). Methods: This is a phase Ib/II study to evaluate the safety and efficacy of the combination of GFH018 and Toripalimab in pts with advanced solid tumors. Patients with RM NPC were enrolled to receive GFH018 80mg twice a day (BID) 14-day-on/14-day-off in combination with Toripalimab 3mg/kg every two weeks. Tumor assessment was performed every 8 weeks per Response Evaluation Criteria in Solid Tumor (RECIST) 1.1. Results: As of 31 Dec 2022, 32 pts with R/M NPC who had progressed on at least one prior line therapy were enrolled. Sixteen (50%) had received ≥3 lines of prior therapies, and 19 (59.4%) had previously received immune checkpoint inhibitors (ICIs) and platinum-based chemotherapies. The median duration of study drug exposure was 7 weeks. Twenty-five pts (78.1%) experienced treatment-related adverse events (TRAEs) of any grades, and 11 pts (34.4%) had ≥ Grade 3. The most common TRAEs (occurring in ≥ 3 pts) were anaemia (n = 6, 18.8%), hyponatraemia (n = 6, 18.8%), rash (n = 6, 18.8%), fatigue (n = 4, 12.5%), white blood cell count decreased (n = 4, 12.5%), aspartate aminotransferase increased (n = 3, 9.4%), back pain (n = 3, 9.4%), decreased appetite (n = 3, 9.4%), hypokalaemia (n = 3, 9.4%), and hypothyroidism (n = 3, 9.4%). As of 18 Jan 2023, among the 27 pts with post-baseline tumor assessments, 8 achieved partial response (PR), and 5 stable disease (SD); the overall response rate (ORR) was 29.6%, and disease control rate (DCR) was 48.1%. Six PR and 2 SD were observed among the 12 pts without prior treatment of ICIs; the ORR was 50%, and DCR was 66.7%. Four pts discontinued treatment without any post-baseline tumor assessments due to AEs or withdrawal of consent, and 1 patient is premature for tumor assessment. Conclusions: GFH018 combined Toripalimab was well tolerated and demonstrated preliminary efficacy in pts with R/M NPC. Specifically, in pts who had not previously received ICIs, promising antitumor activity was observed supporting further investigation to this group of pts. Clinical trial information: NCT04914286 .

Fruquintinib plus sintilimab in patients with either treatment-naive or previously first line treated metastatic clear-cell renal cell carcinoma (ccRCC): Results from a multicenter, single-arm phase 2 study.

e16514 Background: Antiangiogenic therapy combined with immunotherapy significantly improved the progression-free survival (PFS) and preliminary survival benefit for advanced clear-cell renal cell carcinoma (ccRCC). However, no combined immune therapies are currently approved for ccRCC in China. Fruquintinib (F, a highly selective VEGFR inhibitor) combined with sintilimab (S, an anti-PD-1 monoclonal antibody) showed encouraging antitumor activity in multiple solid tumors. Here, we reported the results of F plus S in metastatic ccRCC cohort from an open-label, single-arm phase 2 study (NCT03903705). Methods: Patients (pts) with pathologically confirmed metastatic ccRCC who were treatment-naive or had failed previously first-line treatment were eligible. They received F (5 mg, 2 weeks on/1 week off, orally, QD) plus S (200 mg, IV, Q3W) in 21-day cycles until disease progression or unacceptable toxicity; treatment of S was allowed for up to 24 months. The primary endpoint was objective response rate (ORR) per RECIST v1.1. Results: As of cutoff (November 30, 2022), a total of 42 pts (22 treatment-naïve pts, and 20 previously first-line treated pts) were enrolled and received the combination treatment. Median (range) age was 59.0 (34.2-72.4) years; 34 (81.0%) pts were male. Among previously treated pts, 19 (19/20, 95.0%) pts had received VEGFR therapy as prior first-line treatment, including sunitinib (3/20, 15.0%), pazopanib (7/20, 35.0%), axitinib (2/20, 10.0%) and others (7/20, 35.0%). International Metastatic RCC Database Consortium (IMDC) risk included: favorable in 15 (35.7%) pts, intermediate in 22 (52.4%) pts, and poor in 5 (11.9%) pts. The median follow-up duration was 14.8 months (m) and 23.3 m for treatment-naive and previously treated pts, respectively. All pts had at least 1 post-baseline tumor assessment. Confirmed ORR was 68.2% and 60.0%, median duration of response was not reached (NR) and 13.9 m, and disease control rate was 95.5% and 85.0% for treatment-naive and previously treated pts, respectively. Median PFS (mPFS) was NR and 12m-PFS rate was 64.8% in treatment-naive pts; mPFS was 15.9 m in previously treated pts. The median treatment duration of F and S was both 14.7 m. All pts experienced at least 1 treatment-emergent adverse event (TEAE). Common (≥5%) grade ≥3 TEAEs were hypertension (21.4%), hypertriglyceridaemia (9.5%), amylase increased (7.1%), cerebral infarction (7.1%) and proteinuria (7.1%). No new safety signals were observed. Conclusions: F plus S demonstrated a favorable efficacy with manageable toxicity for treatment-naive and previously first-line treated metastatic ccRCC. A phase 2/3 study is being conducted to confirm this combination efficacy in the second-line treatment of ccRCC (NCT05522231). Clinical trial information: NCT03903705 .

A phase 2 study of HMPL-453, a selective FGFR tyrosine kinase inhibitor (TKI), in patients with previously treated advanced cholangiocarcinoma containing FGFR2 fusions.

e16118 Background: Patients (pts) with advanced cholangiocarcinoma (CCA) who progressed on or after 1L chemotherapy have few treatment options. FGFR2 fusions or rearrangements occur in 10–16% of pts in global and 6.14% in Chinese pts with intrahepatic cholangiocarcinoma (iCCA), and may predict tumor susceptibility to FGFR inhibitors. HMPL-453 is a novel, selective tyrosine kinase inhibitor against FGFR1, 2, and 3. Here, we report results from an open-label, multi-cohort, single-arm phase 2 study (NCT04353375). Methods: Pts with histologically or cytologically confirmed locally advanced or metastatic iCCA with FGFR2 fusions who were treated at least one previous line of systemic therapy were eligible and included in this analysis. They received 21-day cycles of HMPL-453 orally with 150 mg (QD, cohort 1) or 300 mg (QD, 2w on/1w off, cohort 2) until disease progression or unacceptable toxicity. The primary endpoint was objective response rate (ORR) per RECIST 1.1. Results: At data cutoff (Sep 21, 2022), a total of 25 iCCA pts (12 in cohort 1, 13 in cohort 2) were enrolled and treated with HMPL-453. Median age was 51 yrs (range 28-76) and 12 (48%) were male. All pts had received ≥1 prior treatment line and 21 (84%) had received previous gemcitabine-based chemotherapy. The median follow-up duration was 12 months (mos) and 4.1 mos for cohort 1 and cohort 2, respectively. Of 22 evaluable pts (12 in cohort 1 and 10 in cohort 2) who had at least one post-baseline tumor assessment, the best overall response by investigator assessment was confirmed partial response in seven (31.8%) pts and stable disease in an additional 12 pts (54.5%), resulting in a disease control rate (DCR) of 86.4%. Specifically, in cohort 2 the confirmed ORR was 50% (95% CI, 18.7%–81.3%) and DCR was 90% (95% CI, 55.5%–99.7%). Duration of response was not reached in either cohort. Median progression-free survival was 5.7 (95% CI, 2.6, NR) mos in cohort 1 and not yet mature in cohort 2. Of all pts, 23 (92%) experienced ≥1 treatment-related adverse events (TRAEs). The most common TRAEs (any grade) were diarrhea (56%), dry mouth (44%), and blood phosphorus increased (44%). The common Gr ≥3 TRAEs (≥5% pts) were decreased neutrophil count (8%), nail toxicity (8%) and palmar-plantar erythrodysesthesia syndrome (8%). Compared to cohort 1, pts in cohort 2 experienced a lower incidence of Gr ≥3 TRAEs (23.1% vs 58.3%), less dose interruption/reduction (32.0% vs 41.7%) and less treatment discontinuation (0.0% vs 16.7%) due to TRAE. Based on the better safety profile and preliminary efficacy, 300mg, QD, 2w on/1w off was chosen as the recommended phase 2 dose (RP2D). Conclusions: HMPL-453 showed promising efficacy, particularly in RP2D regimen (300 mg, QD, 2w on/1w off) and acceptable toxicity in pts with previously-treated advanced iCCA and FGFR fusions. These results warrant further study in pts with advanced iCCA. Clinical trial information: NCT04353375 .

Safety and efficacy of QL1706 plus carboplatin/etoposide (EC) as first-line (1L) treatment for extensive-stage small-cell lung cancer (ES-SCLC): The results from a phase II single-arm study.

8525 Background: Although the combination of PD-L1 inhibitor and platinum-etoposide chemotherapy has been the preferred 1L treatment for patients (pts) with ES-SCLC, the clinical benefit of the addition of PD-L1 inhibitor was still modest. QL1706 is a novel bifunctional antibody, containing a mixture of anti-PD-1 IgG4 and anti-CTLA-4 IgG1 antibodies produced by MabPair. In phase I trials, QL1706 monotherapy has shown promising antitumor efficacy in nasopharynx cancer and cervical cancer, as well as other advanced solid tumors including SCLC (to be published). This study aims to assess the safety and efficacy of QL1706 plus EC in treatment-naïve ES-SCLC. Methods: In this phase II, open-label, single-arm, multi-center study, eligible pts (18-75 years, ECOG 0-1) received 4-6 cycles of QL1706 (5mg/kg, IV, Q3W) plus EC (etoposide, 100 mg/m2, D1-3, Q3W; carboplatin, AUC = 5, D1, Q3W), followed by the maintenance therapy of QL1706 until disease progression, intolerable toxicity or other discontinuation events defined in the study protocol. Tumor imaging was performed every 6 weeks for the first year and every 9 weeks thereafter. The primary endpoint is safety. Results: From Apr 18, 2022 to Jul 27, 2022, a total of 40 pts were enrolled with a median age of 58.5 years (range, 38−73). 87.5% pts were men, 80% were smokers and 90% had ECOG PS of 1. As of data cutoff (Jan 16, 2023), the median QL1706-treatment duration was 5.9 (range, 0.7−8.9) mo. Twenty pts remained on treatment and 20 pts discontinued due to progressive disease (16, 40.0%) or patient decision (4, 10.0%). Thirty two (80.0%) pts had at least one TRAE (QL1706-related). Fifteen (37.5%) pts experienced grade 3-4 TRAEs, including neutropenia (8, 20%), thrombocytopenia (4, 10%), anemia (3, 7.5%), WBC count decreased (2, 5.0%), AST increased (2, 5.0%), ALT increased (1, 2.5%), gamma-GT increased (1, 2.5%), rash (1, 2.5%), and diarrhea (1, 2.5%). No grade 5 TRAE occurred. No AE led to discontinuation of any treatment. Of the 39 pts who had at least 1 post-baseline tumor assessment, 37 achieved PR (35 confirmed and 2 unconfirmed) and 1 achieved SD. Thus, the confirmed ORR was 89.7% (95% CI, 75.8%−97.1%), and the DCR was 97.4% (95% CI, 86.5−99.9%) (per RECIST v1.1). The mDoR was 4.5 (95% CI, 4.2−not evaluable) mo, with the longest response duration more than 7.2 mo and ongoing. The mPFS was 5.7 (95% CI, 5.4−7.1) mo, together with 3 mo- and 6 mo-PFS rates of 94.8 (95% CI, 80.8−98.7%) and 44.7% (95% CI, 27.3−60.6%), respectively. With a median follow-up time for OS of 6.2 mo, the mOS has not been reached. Conclusions: QL1706 plus EC chemotherapy showed tolerable safety profile and promising efficacy as first-line treatment for pts with ES-SCLC. These data support further clinical development of QL1706 in ES-SCLC. Clinical trial information: NCT05309629 .

Camrelizumab combined with lenvatinib and RALOX-HAIC for hepatocellular carcinoma (HCC) in BCLC stage B and C: A prospective, single-arm, phase II trial (Cal Era study).

e16128 Background: The combination of systemic therapies and hepatic arterial infusion chemotherapy (HAIC) showed promising outcomes for advanced hepatocellular carcinoma (HCC). Raltitrexed, an antimetabolic drug with long plasma concentrations half-life, could be used in short infusions. HAIC with raltitrexed plus oxaliplatin (RALOX) was reported to be effective and safe in HCC. This study aimed to investigate the efficacy and safety of combined camrelizumab and lenvatinib plus RALOX-HAIC as a first-line treatment in advanced HCC patients. Methods: This single-arm, phase II study included treatment-naive adult (≥18 years) patients with HCC in BCLC stage B and C and Child-Pugh score small or equal to 7 points (NCT05003700). Patients were administrated with RALOX-HAIC (oxaliplatin 100mg/m2, raltitrexed 3 mg/m2, every 3 weeks), combined with camrelizumab (200mg by IV infusion, every 3 weeks) and lenvatinib (8mg orally once daily) for 6 cycles, followed by maintenance therapy with camrelizumab and lenvatinib until disease progression or unacceptable toxicity. The primary endpoint was objective response rate (ORR). Results: Between March 2021 and October 2022, 36 patients (33 men and 3 women; median age, 54.5 years) were enrolled. The median tumor size was 11.4 cm, 86.1% of patients had portal vein invasion, and 38.9% had extrahepatic metastasis. As of February 1, 2023, the median follow-up was 14.2 months, and all patients had at least one post-baseline tumor assessment. The confirmed ORR per RECIST v1.1 and per mRECIST was respectively 61.1% (95% CI, 44.4−77.8), and 83.3% (95% CI, 70.5−96.1) including 4(11.1%) patients who achieved a complete radiological response. The median progression-free survival (PFS) time was 13.8 months (95%CI, 8.8-20.5) per RECIST v1.1. The 6-month and 12-month overall survival rate were 94.3% and 64.9%, respectively. Grade 3-4 treatment-related adverse events (AEs) occurred in 75% of patients, and the most common were neutropenia (44.4%) thrombocytopenia (36.1%), elevated aspartate aminotransferase (25.0%), and leucopenia (19.4%). All AEs were expected and manageable, and no treatment-related deaths were reported. Conclusions: Combination treatment with camrelizumab and lenvatinib plus RALOX-HAIC showed promising antitumor activity and acceptable toxicity in patients with advanced HCC. Clinical trial information: NCT05003700 .

EZH2/EZH1 inhibitor tulmimetostat (CPI-0209) in patients with advanced solid tumors or hematologic malignancies: Preliminary phase II results.

3094 Background: Many preclinical tumor models with mutations in ARID1A and BAP1 are highly sensitive to EZH2 inhibition. Tulmimetostat (CPI-0209) is an investigational oral, next-generation, dual EZH2/EZH1 inhibitor with durable target coverage. Phase I dose escalation established a recommended Phase II dose of 350 mg (Lakhani et al. ASCO 2021). We report preliminary Phase II findings from the ongoing Phase I/II study (NCT04104776). Methods: Phase II is evaluating tulmimetostat 350 mg once daily in 28-day cycles in 6 disease-based cohorts (Table). The Simon 2-stage study design requires 1 response (complete [CR] or partial [PR]) in stage 1 (n = 10 patients [pts]) for expansion to stage 2 (plus n = 19) (except in M4, see table). Primary endpoint is objective response rate (ORR) based on disease-specific criteria; secondary objectives include safety. Results: As of Nov 08, 2022, 62 pts received ≥1 dose (safety evaluable); 48 had ≥1 postbaseline tumor assessment (efficacy evaluable). Pts had median 3.2 years (0.6–19.6) since diagnosis; 77.4% had ≥2 prior lines of therapy. Cohorts M2, M5 and M6 had completed stage 1 enrollment. At cut-off, best responses among evaluable patients (Table) show 4 cohorts have at least 1 confirmed response, including 2 CR and 1 PR in 7 pts with peripheral T-cell lymphoma (PTCL). 47 pts (75.8%) experienced TEAEs leading to dose modifications, 20 (32.3%) had serious TEAEs, and 5 (8.1%) discontinued treatment due to TEAEs. The most frequent TEAEs (≥15% of pts) (any Grade/Grade ≥3) considered at least possibly related to tulmimetostat were thrombocytopenia (51.6%/27.4%), diarrhea (45.2%/12.9%), nausea (37.1%/0%), anemia (30.6%/16.1%), fatigue (29.0%/0%), alopecia (25.8%/1.6%), dysgeusia (24.2%/0%), vomiting (21.0%/0%), and neutropenia (17.7%/14.5%). Conclusions: Based on response criteria of ORR ≥1/10 pts, the ovarian (M2), endometrial (M3), and mesothelioma (M5) cohorts achieved eligibility for stage 2 expansion (not relevant in M4). The safety profile of tulmimetostat is consistent with EZH2 inhibition and previous data. These preliminary findings in heavily pretreated pts with multiple tumor types, including tumors with ARID1A alterations or BAP1 loss, support ongoing investigation of tulmimetostat. Clinical trial information: NCT04104776 . [Table: see text]