Common Treatment-related Adverse Events Research Articles

Neoadjuvant serplulimab in combination with concurrent chemoradiotherapy for locally advanced, resectable esophagogastric junction adenocarcinoma.

e16103 Background: Surgery combined with perioperative therapy was recommended as standard treatment for patients with locally advanced esophagogastric junction (EGJ) adenocarcinoma, but the survival rate was still poor. Immunotherapy has shown antitumor activity and an acceptable safety profile in advanced EGJ cancer. The aim of this study was to evaluate the efficacy and safety of neoadjuvant Serplulimab combined with concurrent chemoradiotherapy in previously untreated locally advanced resectable EGJ adenocarcinoma. Methods: Eligible patients with resectable EGJ(Siewert Type II and Type III, Siewert classification 2000)adenocarcinoma stage cT3-4 or N+ were enrolled. Patients received neoadjuvant Serplulimab (300mg on day 1) plus SOX(oxaliplatin at 130mg/㎡on day 1; TS1 40-60mg two times per day on D1-D14, Q3W) in first cycle, followed by Serplulimab (300mg on day 1) combined with concurrent chemoradiotherapy (Reduced SOX regimen: oxaliplatin at 100mg/㎡on day 1, TS1 40-60mg two times per day on D1-D14, Q3W; Radiotherapy dose:45Gy in 25f) in second and third cycle. The patient finished the preoperative treatment and rested for 6-8 weeks for surgery. The primary endpoint was pathological complete response (pCR) rate. Secondary endpoints were major pathological response(MPR) rate, R0 resection rate, objective response rate(ORR), disease-free survival(DFS), overall survival(OS), and toxicity. Results: From March 8, 2023 to January 31,2024,15 patients were enrolled. Nine patients completed neoadjuvant therapy. Eight of these patients underwent radical surgical resection. One out of nine achieved a confirmed pathological complete response (pCR) after three cycles of neoadjuvant treatment. Additionally, two out of nine patients achieved major pathological response(MPR). So, the pCR rate was 11.1%, and the MPR rate was 22.2%. The Tumor and Lymph Nodes downstaging rates are 62.5% and 87.5%, respectively. The median DFS and OS were not reached. In terms of safety, fifteen patients who received at least one cycle of neoadjuvant therapy were included. The most common treatment-related adverse events(TRAE) across all grades were nausea/vomiting(6/15), anorexia(5/15), thrombocytopenia(4/15), and fatigue(4/15). Four patients (26.7%) had grade≥3 adverse events during preoperative therapy, with thrombocytopenia(3/15) and hepatic veno-occlusive disease(1/15). Immune-related adverse reactions(irAE) included myositis(1/15) and rash(1/15), both were grade 1. No grade 4 or higher TRAEs were observed. Conclusions: Initial benefits were demonstrated when using Serplulimab with concurrent chemoradiotherapy for the treatment of locally advanced, resectable EGJ adenocarcinoma patients. The efficacy and safety of Serplulimab with chemoradiotherapy will be further investigated in this trial later. Clinical trial information: NCT05918419 .

Phase I/II first-in-human study to evaluate the safety and efficacy of tissue factor-ADC MRG004A in patients with solid tumors.

3002 Background: Tissue factor (TF) overexpression is associated with thrombosis, metastasis and poor prognosis in solid tumors, including cervical and pancreatic cancer. MRG004A is a novel anti-TF monoclonal antibody conjugated (ADC) to MMAE payload (drug-to-antibody ratio: 3.8), utilizing Glycoconnect site-specific conjugation technology. Herein, we present the preliminary safety and efficacy data from phase I/II MRG004A-001. Methods: This is an interim report (Data cutoff: Dec 15, 2023) of first-in-human, dose-escalation and expansion study ongoing in the USA and China. Pts with ECOG 0-1 with unresectable/metastatic solid tumor with measurable disease per RECIST v1.1 that progressed on prior systemic therapy, received MRG004A monotherapy Q3W intravenously. The primary objectives were to assess the safety, activity, maximal tolerated dose (MTD) and recommended phase 2 dose (RP2D). Baseline tissue was evaluated for the association of TF expression with objective response rate (ORR) and disease control rate (DCR). Results: Sixty-three pts were enrolled with 43 in dose-escalation phase (8 dose levels [0.3-2.6mg/kg]) and 20 in dose-expansion phase (15 at 2.0mg/kg and 5 at 2.4mg/kg). Median age 58 (38-75). ECOG0: 8 (13%) pts. Female: 37 (59%) pts. Median 3 prior lines of therapy: 3 (1-10). MTD was not reached. Sixteen baseline samples were evaluated for overall % membrane positivity by immunohistochemistry. Nineteen were pancreatic cancer (PC) and 68% (13/19) had TF ≥50% and 2 or 3 (+). Five received dose <2 mg/kg Q3W. Significant anti-tumor activity of MRG004A was observed in pts with PC. Among 12 evaluable pts with PC in the 2.0mg/kg cohort, who have received median 3 lines of prior therapy, there were 4 PR and 6 SD. ORR was 33.3% (4/12) and DCR was 83.3% (10/12). Among them, 5 pts with PC of TF expression ≥50% and 3+ intensity and ≤2 prior lines of therapy received MRG004A at 2mg/kg. 4 of 5 TF-overexpressed PC achieved PR and 1 SD. Also, MRG004A showed efficacy in other cancers. In 4 pts with heavily-treated triple-negative breast cancer (TNBC), ORR and DCR were 25% (1/4) and 50% (2/4), respectively. In 2 pts with cervical cancer with four prior therapy lines, 1 PR and 1 SD. Common treatment-related adverse events (TRAE) of any grade include conjunctivitis (27%), anemia (17%), and hypoalbuminemia (13%) and 7.9% (5/63) pts had serious adverse events. One pt with TNBC treated at 1.8mg/kg experienced G3 Steven Johnson Syndrome, a dose-limiting toxicity (DLT), but resolved. No other DLT was observed and dose expansion and matured outcome evaluation is ongoing. Conclusions: MRG004A demonstrated a manageable toxicity and a striking antitumor activity across multiple tumor types with high TF expression in heavily pretreated setting, including pancreatic cancers. These encouraging findings warrant further evaluation of MRG004A, particularly in the context of TF-overexpressed solid tumors. Clinical trial information: NCT03941574 .

Efficacy and safety of disitamab vedotin (RC48) in HER2-expressing breast cancer: A multicenter retrospective study.

e13011 Background: RC48 is an Antibody-Drug Conjugate (ADC) that integrates a humanized monoclonal antibody targeting human epidermal growth factor receptor 2 (HER2) linked to the microtubule inhibitor monomethyl auristatin E (MMAE). This study reports real-world data using RC48 monotherapy in HER2-expressing advanced breast cancer (ABC). Methods: The study reviewed patients with HER2-expressing ABC who received RC48 monotherapy at three hospitals in China between September 2021 and June 2022. The electronic medical record was used to collect the clinical characteristics of the patient and to evaluate the antitumor activity and safety. The primary outcome was real-world progression-free survival (rwPFS). Results: A total of 15 patients were included, of whom 9(60%) were HER2-positive and 6(40%) had HER2 low expression (IHC 1+ or IHC 2+/ISH-).11 patients (73.3%) had visceral metastases, 40% of patients (6/15) had central nervous system (CNS) metastases at baseline. 6 patients (40%) had ≥3 metastatic lesions, and 13(86.7%) of patients received RC48 as third-line treatment or higher. Progression-free survival (PFS), overall survival (OS), and response can be assessed in all patients. The median follow-up was 10 months and the median rwPFS was 8.0 months (95% CI, 4.897-11.103), while the median OS was not reached. Objective response rate (ORR) and disease control rate (DCR) were 46.7% and 80% respectively. Partial response (PR) was achieved in 46.7% of the patients (7/15). patients with HER2-positive and HER2 low expression, the median rwPFS was 8.77 and 4.63 months, respectively (HR = 0.49,95% Cl, 0.13-1.80, P = 0.196), and in 6 patients with CNS metastases, the median rwPFS was 7.5 months (95% CI, 2.82-18.28). The most common treatment-related adverse events (TRAEs) were elevated transaminase (33.3%) and Leukopenia (33.3%), most of which were grade 1-2, No serious adverse events related to treatment were observed. Conclusions: The novel HER2-targeted ADC, RC48, demonstrated promising preliminary antitumor activity in patients with HER2-expressing ABC, patient with brain metastases could also benefit, with tolerable toxicities.

Durvalumab plus gemcitabine/cisplatin/nab-paclitaxel in resectable biliary tract cancer: A phase II, single-arm, open-label study (DurGAP).

e16260 Background: Biliary tract cancer (BTC) presents a formidable challenge, marked by its aggressive nature and dismal prognosis. While surgical resection remains the lone potentially curative option, 5-year survival rates have plateaued below 50%, largely due to high rates of recurrences and metastases. Given these sobering statistics, the imperative for neoadjuvant therapy to enhance outcomes is evident. Building upon the success of the TOPAZ-1 trial, which established durvalumab in combination with gemcitabine and cisplatin as a standard regimen for advanced BTC, this study seeks to assess the safety and efficacy of incorporating neoadjuvant durvalumab alongside gemcitabine, cisplatin, and Nab-paclitaxel for resectable BTC. Methods: Resectable, treatment-naïve BTC patients (pts) were enrolled and administered 3 cycles of neoadjuvant durvalumab (1000mg, iv, d1, q3w) + GAP (gemcitabine 1000mg/m2, cisplatin 25mg/m2, Nab-paclitaxel 100mg/m2, d1, d8, 21d cycle). Primary endpoints included assessing Adverse Events (AEs) and Objective Response Rate (ORR). Secondary endpoints comprised R0 resection rate, Recurrence-Free Survival (RFS), Overall Survival (OS). Results: Between Feb, 2023 to Jan, 2024, a total of 24 patients were enrolled, 12 (50.0%) were male, all with ECOG 0 and 18 (75.0%) presenting with N1 status. Median age: 65 years. Primary sites: intrahepatic (50.0%), extrahepatic (33.3%), gallbladder (16.7%). Median follow-up: 8.75 months; all pts received ≥2 neoadjuvant cycles. The ORR was 62.5%, with all 15 pts demonstrating partial responses (PR). The DCR was 87.5% with 15 PR and 6 stable disease (SD) responses. The most common treatment-related adverse events (TRAEs) were increased ALT/AST (28.6%), anemia (21.8%), hypoalbuminemia (16.0%). Grade ≥3 TRAEs occurred in 2 (8.3%) pts. 13 pts underwent resection, achieving R0 resection in 12 (92.3%) of cases, comprising 10 PR, 2 SD, and 1 pt deemed eligible for surgery post-assessment despite a PD response. 11 pts did not undergo resection, with reasons including patient refusal (4 PR, 1 SD), not meeting resection criteria (2 PD), lost to follow-up (1 PR, 1 SD), and still under active follow-up (2 SD). Conclusions: Neoadjuvant durvalumab combined with gemcitabine/cisplatin/Nab-paclitaxel demonstrated a promising ORR and DCR, with a tolerable safety profile, warranting further investigations in a larger cohort. Clinical trial information: NCT05640791 .

Inhibition of lysine acetyltransferase KAT6 in ER+HER2− metastatic breast cancer: a phase 1 trial

Inhibition of histone lysine acetyltransferases (KATs) KAT6A and KAT6B has shown antitumor activity in estrogen receptor-positive (ER+) breast cancer preclinical models. PF-07248144 is a selective catalytic inhibitor of KAT6A and KAT6B. In the present study, we report the safety, pharmacokinetics (PK), pharmacodynamics, efficacy and biomarker results from the first-in-human, phase 1 dose escalation and dose expansion study (n = 107) of PF-07248144 monotherapy and fulvestrant combination in heavily pretreated ER+ human epidermal growth factor receptor-negative (HER2−) metastatic breast cancer (mBC). The primary objectives of assessing the safety and tolerability and determining the recommended dose for expansion of PF-07248144, as monotherapy and in combination with fulvestrant, were met. Secondary endpoints included characterization of PK and evaluation of antitumor activity, including objective response rate (ORR) and progression-free survival (PFS). Common treatment-related adverse events (any grade; grades 3–4) included dysgeusia (83.2%, 0%), neutropenia (59.8%, 35.5%) and anemia (48.6%, 13.1%). Exposure was approximately dose proportional. Antitumor activity was observed as monotherapy. For the PF-07248144–fulvestrant combination (n = 43), the ORR (95% confidence interval (CI)) was 30.2% (95% CI = 17.2–46.1%) and the median PFS was 10.7 (5.3–not evaluable) months. PF-07248144 demonstrated a tolerable safety profile and durable antitumor activity in heavily pretreated ER+HER2− mBC. These findings establish KAT6A and KAT6B as druggable cancer targets, provide clinical proof of concept and reveal a potential avenue to treat mBC. clinicaltrial.gov registration: NCT04606446.

Utidelone for heavily pretreated metastatic castration-resistant prostate cancer after failing docetaxel treatment: An open-label, single-arm, phase II trial.

e17036 Background: The appropriate chemotherapy for metastatic castration-resistant prostate cancer (mCRPC) that progressed after docetaxel treatment remains unmet medical needs. Utidelone (UTD1) is a genetically engineered epothilone analog with antitumor activity in taxane-resistant cancers. UTD1 was approved for advanced breast cancer in 2021. This study was designed to evaluate the safety and efficacy of UTD1 in mCRPC. Methods: In this perspective, phase II clinical trial, men with progressive mCRPC after docetaxel and abiraterone, and/or enzalutamide, and/or apalutamide received UTD1 monotherapy treatment at a total dose of 150 mg/m2 for five days intravenous, every three weeks until disease progression, or intolerable toxicity, or death. We reported the preliminary results for potential benefits in this new treatment. The primary endpoint was prostate specific antigen (PSA) response rate, defined as a 50% or greater reduction in serum PSA. The secondary endpoint included investigators-assessed objective response rate (ORR) and disease control rate (DCR) according to RECIST v1.1, radiographic progression-free survival (rPFS) according to PCWG3 criteria, overall survival (OS), and safety. The trial was registered at Chinese Clinical Trial Registry (No. ChiCTR2200061635). Results: By January 31st, 2024, twenty-five mCRPC patients with a median age of 67 years were enrolled in this study at Sun Yat-sen University Cancer Center since March 23rd, 2022. Patients received an average of 4.2 lines of prior anticancer treatments: 100% of them received docetaxel, 96.0% of them received abiraterone, and 80.0% progressed after enzalutamide, and/or apalutamide. 28.0% of patients had visceral metastases, and 88.0% patients had bone metastases. At of the cut-off date, the PSA response rate was 16.0%. The median rPFS and OS were 4.9 months and 7.1 months, respectively. One patient had a durable response for 19.2 months and had been remaining on study treatment to date. One PR and four SD were observed in ten patients with measurable lesions, resulting in an overall ORR and DCR of 10.0% and 50.0%, respectively. The most common treatment-related adverse events (TRAEs) including peripheral sensory neuropathy (76.0%), dyspepsia (72.0%), anemia (64.0%), constipation (60.0%), fatigue (64.0%), nausea (36.0%), leukocytopenia (32.0%), arthralgia (32.0%), dizziness (32.0%), vomiting (20.0%), and diarrhea (20.0%) were manageable. The 3/4 grade TRAEs included anemia (16.0%), and diarrhea (4%). No treatment-related death occurred. Conclusions: UTD1 has demonstrated promising efficacy and favorable tolerance in heavily pretreated mCRPC patients after progression on docetaxel in the preliminary analyses. Additional randomized trials are warranted for this new regimen. Clinical trial information: ChiCTR2200061635.

Cadonilimab in combined with gemcitabine and cisplatin in advanced biliary tract cancer (BicureX): A phase II, single-arm clinical trial.

e16158 Background: PD-1 or PD-L1 inhibitors plus chemotherapy as the first-line treatment has been proven to be effective in improving the prognosis of advanced biliary tract cancer (BTC) patients. However, there is still considerable demand for further improvement of BTC patients’ prognosis. This trial aims to evaluate the efficacy and safety of Cadonilimab (PD-1/CTLA-4, a bi-specific antibody) plus gemcitabine and cisplatin for patients with advanced BTC in first -line treatment. Methods: In this phase II, single-arm trial, we will enroll 65 patients with previously untreated, unresectable, locally advanced or metastatic BTC, including intrahepatic or extrahepatic cholangiocarcinoma (ICC/ECC) and gallbladder carcinoma (GBC). Participants received Cadonilimab (10 mg/kg, days 1, every three weeks) plus gemcitabine (1000 mg/m2, days 1, 8, Q3W), and cisplatin (25 mg/m2, days 1, 8, Q3W) for up to eight cycles, followed by Cadonilimab (10 mg/kg, days 1, Q3W) until disease progression or unacceptable toxicity. Treatment response was evaluated with image-based assessment according to response evaluation criteria insolid tumors (RECIST) version 1.1. by two experienced experts and further explored multiple methods, such as 3D visualisation and Spectral computed tomography Scan. The primary endpoint was the objective response rate (ORR); the secondary endpoints are disease control rate (DCR), progression-free survival (PFS), overall survival (OS), and safety. Exploratory endpoints included associations between response, molecular characteristics, and the immune microenvironment. Results: Between June 30, and January 31, 2024, a total of 30 patients have undergone at least one imaging evaluation. 66.7% of these patients were diagnosed with ICC, 23.3% with GBC, and 10% with ECC. The mean age was 58.4 years, and 60% of the patients were male. 24 (80%) patients had metastasis. Among them, 1 (3.3%) patient acheived complete response (CR), 15 (50%) patients had partial response (PR) and 8 (26.7%) patients presented with stable disease (SD). The ORR was 53.3% and the DCR was 80%. The most common treatment-related adverse events (TRAEs) of any grade were rash (80%) and anaemia (76.7%). Grade 3 TRAEs were observed in 66.7% of the patients. The most frequent grade 3 TRAEs were anaemia (33.3%), and leukocytopenia (33.3%). No grade 4 or 5 events were observed. All patients were microsatellite stable (MSS), and the median TMB was 2.88 (0-109.44) Muts/Mb. Conclusions: Cadonilimab plus gemcitabine and cisplatin shown a promising efficacy and acceptable safety profile as first-line treatment for advanced BTC patients. Clinical trial information: NCT05978609 .

A phase I clinical trial investigating the safety, tolerability, and pharmacokinetics of HX301 (narazaciclib), a novel multi-kinase inhibitor targeting CSF1R, CDK 4/6, and ARK5, in patients with advanced solid tumors.

e15106 Background: HX301 (narazaciclib) is a promising novel multi-kinase inhibitor with potent activity against Colony Stimulating Factor 1 Receptor (CSF1R), Cyclin-Dependent Kinase 4/6 (CDK4/6), and Aurora Kinase 5 (ARK5), with a half-maximal inhibitory concentration (IC50) values in 0.29-4.95 nM range. It is an oral bioavailable agent and has the ability to cross blood-brain barrier. Preclinical data have showed significant antitumor activities, warranting further clinical trials to evaluate the safety, and potential efficacy in human subjects. Methods: Utilizing the standard 3+3 design, the study aimed to evaluate the safety, tolerability and pharmacokinetics of ascending doses of HX301. Patients with heavily pretreated advanced solid tumors received HX301single agent via oral administration, with doses ranging from 40mg to 200mg once daily for the first 21 days of each 28-day cycle. Results: As of December 27, 2023, a total of 20 patients (5 males, 15 females) were enrolled in the study, with varying doses of HX301 administered: 40 mg (n=3), 80 mg (n=3), 120 mg (n=4), 160 mg (n=3), and 200 mg (n=7). The median age of the patients was 55 years, ranging from 30 to 71. Notably, 15 patients (75%) had metastatic breast cancers. Dose-limiting toxicities (DLTs) were observed in 2 patients in the 200 mg group. These included a Grade 4 increase in alanine aminotransferase (ALT) and a Grade 3 decrease in platelet counts with associated epistaxis, both of which resolved after discontinuation of treatment. The most common treatment-related adverse events (AEs) observed were elevated aspartate aminotransferase (AST) (65.0%), decreased white blood cell count (50%), decreased neutrophil count (50%), elevated ALT (45%), elevated creatine kinase (45%), and elevated creatinine (35%). Additionally, 4 patients experienced Grade 3 or higher treatment-related AEs, including 1 patient in the 160 mg group with Grade 3 elevated γ-glutamyl transferase and alkaline phosphatase, and 3 patients in the 200 mg group with Grade 4 elevated ALT and Grade 3 elevated AST and Dyspepsia, Grade 3 decreased neutrophil and platelet counts, and Grade 3 hyperglycemia. Notably, no AEs led to death. Among the 20 patients evaluable for tumor assessment using RECIST 1.1 by Investigators, 4 obtained stable disease, including 2 patients in the 200 mg group, 1 in the 120 mg group, and 1 in the 80 mg group. Furthermore, 1 patient with HR+ breast cancer in the 200 mg group received study drug for over a year and achieved prolonged stable disease for more than 12 months, highlighting a notable clinical outcome. Conclusions: HX301 at dose levels ranging from 40mg to 160mg was tolerable with a manageable toxicity profile. Further clinical studies are needed to explore the drug's anti-tumor activity, particularly in combination settings. Clinical trial information: NCT05731934 .

Prognostic analysis of PD-1/CTLA-4 bispecific antibody combined with chemotherapy first-line treatment for recurrent or metastatic cervical cancer: A multicenter real-world study.

e17520 Background: PD-1/CTLA-4 bispecific antibody, cadonilimab, has shown excellent efficacy in advanced cervical cancer patients who have previously received platinum containing chemotherapy. However, its effectiveness in first-line treatment remains unclear yet. This study aims to evaluate the efficacy, safety, and prognostic biomarker of cadonilimab combined with chemotherapy for the first line treatment of recurrent or metastatic cervical cancer. Methods: Information on patients with recurrent or metastatic cervical cancer who received chemotherapy combined with cadonilimab as first-line treatment at three cancer centers from July 2022 to September 2023 were collected. Patients have not received systemic chemotherapy previously and are not suitable for curative local treatment, received cadonilimab 10mg/kg Q3W for up to 17 cycles + chemotherapy for up to 6 cycles (paclitaxel 135-175 mg/m2 + cisplatin 50 mg/m2 or carboplatin AUC 5), ± bevacizumab 10-15 mg/kg. Clinical outcomes were analyzed using the Kaplan–Meier method with log-rank test. RNA-seq was used to analyze differential expressed genes (DEGs) between PR+CR group and PD+SD group. Results: There are 52 patients enrolled, median age 56.5 years (39–87 years). The median follow-up time was 12 months (5–23 months). There were 29 cases of lung metastasis, 7 cases of liver metastasis, 11 cases of bone metastasis, 12 cases of pelvic metastasis, and 11 cases of lymph node metastasis. The median number of cycles of cadonilimab and chemotherapy were 8 and 5, respectively. The 1-year overall survival (OS) and progression-free survival (PFS) rates were 91% and 72.5%, respectively. The objective response rate (ORR) was 75%.The expression of PD-L1 and bevacizumab had no effect on prognosis. The most common treatment-related adverse events (TRAEs) were neutropenia (78.2%), anemia (82.7%), thrombocytopenia (51.9%), thyroid dysfunction (50%), nausea and vomiting (88.5%), fatigue (71.2%). Grade 3 or 4 adverse events (AE) were reported in 36.5% patients, mainly hematological toxicity. The most significant differential pathways between PR+CR group and PD+SD group were adhesion, Hippo signaling pathway, NOD like receptor signaling pathway, programmed cell death, and secretory granules. Conclusions: Cadonilimab combined with chemotherapy ± bevacizumab as first-line treatment for recurrent or metastatic cervical cancer was effective and well-tolerant.

Transarterial chemoembolization (TACE) combined with donafenib as first-line therapy for unresectable hepatocellular carcinoma (uHCC): A real-world clinical study.

e16145 Background: To evaluate the efficacy and safety of TACE combined with Donafenib, which is as a new tyrosine kinase inhibitors therapy recommended by the China liver cancer staging (CNLC) system for the treatment of unresectable hepatocellular carcinoma (uHCC). Methods: We conducted a single-center, retrospective study on patients diagnosed with uHCC treated by TACE plus Donafenib as the first-line therapy between May 2021 and September 2023 at The First Affiliated Hospital of Sun Yat-sen University. The primary outcomes evaluated in this study were progression-free survival (PFS) and overall survival (OS). Local response, one-year survival rate, safety and tolerability were the secondary outcomes. Results: All of 48 eligible patients by August, 2023, with the median age of 59 years. The clinical characteristics were as follows: BCLC stage A:2 (4.2%), B:16 (33.3%), and C:30 (62.5%); Child-Pugh class A:33 (68.8%) and B:15 (31.2%); ECOG PS 0: 27 (56.2%) and 1: 21 (43.7%). In this study, 10 (20.8%) patients had huge intrahepatic lesions, 15 (31.2%) subjects exhibited extrahepatic metastases at multiple sites, 19 (42.2%) patients presented with portal vein tumor thrombus, and 4 patients were diffuse-type HCC.107 TACE sessions were performed. Three patients had liver transplantation as frequent therapy, and histopathological examination of tissue from these subjects revealed complete necrotic foci. The median PFS was 12.8 months (95% CI: 8.66–NA) , mOS was not reached and the one-year OS rate was 87.5% (95% CI: 77%-97%) in the survival results. The tumor objective response rate was 58.3% with 14.5% complete response and 43.7% partial response based on mRECIST assessment. The disease control rate of the study group was 81.3%. The most common treatment-related adverse events (TRAEs) observed were elevated aspartate aminotransferase (AST) levels (75.0%), increase in bilirubin level (72.9%), elevated alanine aminotransferase (ALT) levels (54.2%), hand-foot syndrome (53.1%), diarrhea (29.1%), rashes (22.9%), hair loss (18.4%) and hypertension (12.5%). Twenty-three (46.9%) patients presented with grade 3 or 4 TRAEs including elevated AST levels (22.4%), elevated ALT levels (16.3%), increase in bilirubin level (4%), diarrhea (4%) and hypertension (2%). No Grade 5 TRAEs were observed. Conclusions: The combination of TACE and Donafenib presented good efficacy and tolerability, which could be potentially used as the first-line treatment of Chinese uHCC patients.

Stereotactic ablative radiotherapy combined with fruquintinib and tislelizumab in metastatic colorectal cancer: Updated findings from a single-arm, prospective phase II trial (RIFLE).

e15570 Background: Stereotactic ablative radiotherapy (SABR) has been shown to sensitize immunotherapy through inducing immunogenic death and remodeling the tumor immune microenvironment. In addition, anti-angiogenic therapy exhibits synergistic antitumor effects with PD-1/PD-L1 antibodies through its immunomodulatory effects for metastatic colorectal cancer (mCRC) patients. Here, we report the updated results from RIFLE trial: the efficacy and safety of the combination of fruquintinib, PD-1 inhibitor tislelizumab and SABR in mCRC patients. Methods: This is a single-center, single-arm, prospective phase II clinical trial (NCT04948034). mCRC patients with at least 2 measurable lesions (≥1 of which can be targeted with radiation and ≥1 lesion outside the radiation field) who have failed ≥ 1L standard therapy will receive SABR followed by fruquintinib (5 mg, d1-14, qd) and tislelizumab (200 mg, d1, q3w) within two weeks from completion of radiation. The percentage change from baseline in the sum of longest diameter of target lesions, consist of specified radiated and non-radiated lesions, will be assessed after at least 2 cycles’ drug treatment. Primary endpoint is best objective response rate (ORR) of target lesions. Secondary endpoints include disease control rate (DCR), duration of response (DoR), progression-free survival (PFS) rate, overall survival (OS) rate and toxicity. Results: From August 2021 to February 2024, 34 patients were included in the trial and 31 in the efficacy analysis. Median age was 62 years, 24 (77.4%) patients were male, 26 (83.9%) had ≥ 3 metastases, and 14 (45.2%) had received ≥ 3 prior lines of systemic therapy. The biological effective dose (BED) for irradiated lesions ranged from 37.5 to 105 Gy. Median study follow-up was 17.3 months (95%CI:13.841-20.759), 24 patients were alive and 13 remained on treatment. 1 patient achieved complete response (CR) for target lesions, 8 partial response (PR), 14 stable disease (SD), illustrating an ORR of 29% and a DCR of 74.2%. Median PFS was 8.8 months (95%CI:5.868-11.732). The most common treatment-related adverse events (TRAEs) were proteinuria (35.5%), hypertension (22.6%) and rash (19.4%). Grade 3-4 AEs occurred in 9 patients, including proteinuria and hypertension, and there were no treatment-related deaths. Conclusions: SABR combined with tislelizumab and fruquintinib shows promising effects and good safety in the treatment of metastatic colorectal cancer, which is expected to provide new therapeutic strategies and improve the prognosis for mCRC patients. Clinical trial information: NCT04948034 . [Table: see text]

Neoadjuvant nivolumab plus paclitaxel/cisplatin- chemo-radiotherapy (neo-NTP-CRT) followed by esophagectomy for locally advanced esophageal squamous cell carcinoma (ESCC): A phase II study.

e16098 Background: Adjuvant nivolumab has shown efficacy in reducing recurrence in patients (pts) with locoregional esophageal cancer harboring pathologic residual disease following neoadjuvant chemoradiotherapy (CRT). However, the efficacy of adding nivolumab to neoadjuvant CRT remains unclear. Methods: We conducted a phase II trial of neoadjuvant nivolumab (240mg IV on D-14, 1, 15, 29), paclitaxel (50mg/m2 IV on D1, 8, 15, 22, 29), cisplatin (30mg/m2 IV on D1, 8, 15, 22, 29) and RT (45Gy given in 25 fractions) followed by esophagectomy 6 to 8 weeks after finishing CRT in pts with locally advanced ESCC, defined as clinical stage cT3-4aN0M0 or cT1-3N1-3M0 according to the AJCC Cancer Staging System 8th ed. (ClinicalTrials.gov Identifier: NCT05130684). The study, in a Simon’s two-stage design, used pathological complete response (pCR) rate as the primary endpoint. Secondary endpoints included feasibility, safety, recurrence free survival (RFS), progression free survival (PFS), and overall survival (OS). Results: Between Jan 2021 and Apr 2023, we enrolled a total of 17 pts. Fifteen were male. The median age was 52 years (range: 44~69). The clinical stage was I, II, and III in 1, 1, and 15 pts, respectively. All pts received neo-NTP-CRT with the following dose-intensities (mean dose intensity [range]): nivolumab (95% [50%~ 100%]), paclitaxel (75% [48%~ 100%], cisplatin (97% [80%~ 100%]), and radiotherapy (100%). Fourteen pts received esophagectomy, and 4 of them achieved pCR (24%). Because pCR for the first stage did not meet the efficacy criteria to move forward to second-stage, the enrollment was discontinued after enrolling 17 pts. During neo-NTP-CRT, the most common treatment-related adverse events (TRAEs) were leukopenia (76%), neutropenia (59%), thrombocytopenia (35%), and skin rash (35%); and the most common grade 3 and 4 TRAEs were leukopenia (24%), neutropenia (6%), and nausea and vomiting (6%). Among 14 pts receiving esophagectomy, 4 experienced surgical complications, including 2 with anastomotic leakage, 1 with subclavian artery rupture, and 1 with pneumonitis; one pt died 263 days after surgery, followed by a prolonged hospital stay due to refractory anastomotic leakage, infectious complications, and tumor progression. The median follow-up duration was 18 months. Median RFS, PFS and OS was 8, 12, and 16 months, respectively. Conclusions: Our data indicate that adding nivolumab to neoadjuvant paclitaxel and cisplatin-based CRT is feasible but does not improve pCR rate in locally advanced ESCC pts. Clinical trial information: NCT05130684 .

Phase II study of sitravatinib in combination with tislelizumab in patients with advanced biliary tract cancer who have failed to at least 1 prior systemic treatment.

4018 Background: In first line of advanced biliary tract cancer (BTC), immune-checkpoint inhibitor (ICI) in combination with cytotoxic chemotherapy is now standard of care supported by TOPAZ-1 and KN-966 studies. With this landscape, new drug development using ICI in second or later line setting is urgent unmet medical needs area. Anti-angiogenic agent induced improved anti-tumor immune responses by increasing tumor antigen presentation and promoting lymphocyte infiltration and migration. Methods: This study is an open-label, phase 2 trial to investigate the efficacy of sitravatinib and tislelizumab (PD1 inhibitor) combination treatment for 2L advanced BTC. Patients who received prior ICI could be enrolled. All patients received sitravatinib 120mg orally once daily in combination with tislelizumab 200mg intravenously once every 3 weeks until disease progression, unacceptable toxicity. The primary endpoint was disease control rate (DCR), with key secondary endpoints including overall response rate (ORR), progression-free survival (PFS), overall survival (OS), and safety. Tissue biopsies were conducted three times in total: screening, the first response evaluation, and disease progression. Blood samples were collected every cycles. (NCT04727996) Results: A total of 43 patients were enrolled. Data-cut off was on July 31, 2023. Median follow-up was 10.5months (95% Confidence interval (CI), 7.03-15.6). 9 patients had received prior ICI. This study met primary endpoint as a DCR of 65.1% in all population. ORR was 20.5% in unselected per-protocol population, and PFS was 4.93 months (95% CI, 3.10-8.87). OS was 10.3months (95% CI, 6.67-18.2). Similar efficacy was observed regardless of prior ICI exposure. The most common treatment-related adverse events (AEs) were sitravatinib-related; hand-foot syndrome (any grade 60.5%, grade 3/4 0%), hypertension (any grade 34.9%, grade 3/4 11.6%). Immune-related AEs (irAEs) were 46.5%, with most irAEs being grade 1-2. In exploratory analysis, patients with homologous recombination deficiency (HRD) detected by baseline tissue NGS (frequency 18.5%) showed higher ORR (60% vs 13.6%), longer PFS (not reached vs 4.87 months) and OS (21.1 vs 8.57 months) than patients without HRD. HRD detected by circulating tumor DNA had a complementary role for patient selection. RNA sequencing showed upregulation in inflammatory signal and downregulation in angiogenesis signal between screening and on-treatment tumor tissue. Responders showed higher inflammatory signaling at baseline and on-treatment tumor tissue compared to non-responders. Conclusions: Sitravatinib/tiselizumab combination as 2L therapy in patients with advanced BTC demonstrated meaningful efficacy and an acceptable safety profile. Especially, patient selection using HRD biomarker might be a promising strategy in this setting. Clinical trial information: NCT04727996 .

A first-in-human, phase 1/2a study of GI-102 (CD80-IL2v3) in patients with advanced or metastatic solid tumors: Initial results from dose escalation.

2598 Background: GI-102 (CD80-IL2v3) is a novel immunocytokine designed to direct IL-2v3 to immune cells and tumor cells. IL-2v3 of GI-102 abolished affinity to IL-2Rα minimizing the impact of IL-2 on Treg cells. Preferential targeting of immune cells and further inhibition of CTLA-4 and PD-L1 via CD80 synergize with potent activity of IL-2v3, resulting in robust proliferation and activation of CD8+ T and NK cells. Here we report preliminary safety and efficacy data of GI-102 from a phase 1/2a trial in patients with metastatic solid tumors. Methods: NCT05824975 is an ongoing, dose escalation (3+3 design) and expansion study to evaluate safety, tolerability, PK, PD and anti-tumor activity of GI-102. Each dose level allows to enroll additional 7 patients to fully inform the safety, PK and PD at that dose level. GI-102 was administered intravenously every 3 weeks until disease progression or unacceptable toxicities. Disease was assessed every 6 weeks using RECIST v1.1. Results: As of 12 Jan 2024, 32 patients were treated in dose escalation: 8 at dose level 0.06 mg/kg, 10 at 0.12 mg/kg, 9 at 0.24 mg/kg and 5 at 0.45 mg/kg. Patients had received median of 3 [1-7] prior lines of therapy, including 25.0% (8/32) who had received ≥ 5 lines and 68.8% (22/32) had experienced immune checkpoint blockade (ICB). No dose-limiting toxicities (DLTs) were observed until the highest dose of 0.45 mg/kg Q3W. The most common treatment-related adverse events (TRAEs, ≥ 10%) were pyrexia [43.8%] and chills [34.4%]. 5 patients [15.6%] had ≥ Grade 3 TRAEs and no patient reported TRAEs leading to discontinuation of GI-102. In 23 patients (7 cutaneous melanoma, 4 non-small cell lung cancer, 3 ovarian cancer and others) who had at least 1 post-treatment tumor assessment, objective responses were observed in 17.4% (4/23). In patients with metastatic melanoma who previously experienced ICB, overall response rate (ORR) and disease control rate (DCR) was 42.9% (3/7) and 85.7% (6/7), respectively, including 3 confirmed partial responses (cPR). The median time to response (TTR) was 6 weeks and duration of response (DoR) was 6.0+, 2.4+ and 1.7+ month, respectively. In patients with metastatic ovarian cancer, ORR and DCR were 33.3% (1/3) and 66.7% (2/3), respectively, including 1 cPR [TTR of 6 weeks; DoR 1.9+ month]. Preliminary PK profile showed target-mediated drug disposition with a half-life of ~48 hours. 0.24 mg/kg of GI-102 resulted in a significant expansion of peripheral lymphocytes, CD8+ T cells (effector & memory) and NK cells, by 4.4 [2.1-9.6], 3.9 [2.0–5.7] and 20.4 [9.5–32.6]-fold change from baseline, respectively. There was no meaningful increase in Treg cells. Conclusions: GI-102 was well tolerated up to dose of 0.45 mg/kg Q3W with meaningful monotherapy activity, regardless of previous ICB experience, in patients who failed on standard of care. The dose-escalation is currently ongoing to identify RP2D. Clinical trial information: NCT05824975 .

Clinical efficacy and safety analysis of immune checkpoint inhibitors combined with concurrent chemoradiotherapy for stage IIIC1-IVA cervical cancer: A prospective cohort study.

e17505 Background: Stage IIIC1 with larger/more short lymph node diameters and IIIC2-IVA cervical cancer patients had a particularly poor prognosis. Clinical practices have found that stage IIIC1-IVA patients diagnosed with pelvic lymph node short diameter ≥ 1.5cm/number of positive lymph nodes ≥ 3, or paraaortic lymph node metastasis, had a higher recurrence rate and lower overall survival rate. The overall survival rate is approximately 29% -52%. Sequential systemic chemotherapy after concurrent chemoradiotherapy (CCRT) can not improve survival in such patients. However, the current research results on the combination of CCRT with immune checkpoint inhibitors for cervical cancer are not ideal, which may be due to the lack of stratified analysis. This study compared the efficacy and safety of CCRT and combined use of immune checkpoint inhibitors (non sequential) for stage IIIC1-IVA cervical cancer through the cohort analysis, and analyzed the prognostic factors. Methods: Patients diagnosed with stage IIIC1-IVA cervical cancer who underwent concurrent chemoradiotherapy from October 2019 to October 2022 were enrolled. Patients were divided into the study group (35 cases) receiving Sintilimab concurrently with chemoradiotherapy and the control group (35 cases) receiving standard treatment. The primary endpoints were the assessment of one-year progression-free survival (PFS), objective response rate (ORR), and associated influencing factors. Secondary endpoints included treatment-related adverse events (TRAEs). Results: The one-year PFS rates were 88.6% in the study group and 62.9% in the control group, showing a significant difference (χ2=6.293, P=0.012). The median PFS was not reached. The ORR for tumor response was 74.30% in the study group, significantly higher than the 51.43% in the control group (P=0.048). Univariate analysis identified tumor maximum diameter (p = 0.01) and concurrent use of ICIs (p = 0.039) as prognostic factors for PFS. Multivariate Cox analysis also revealed tumor maximum diameter (p = 0.0121) and concurrent use of ICIs (p=0.049) as independent predictors of PFS. The most common TRAEs in both groups included leukopenia, decreased appetite, nausea/vomiting, and fatigue, with no significant differences in incidence (P>0.050). Grade ≥3 TRAEs were most frequently leukopenia (47.5%) and thrombocytopenia (17.1%) in the study group and leukopenia (51.4%) in the control group. All adverse reactions were alleviated after symptomatic treatment, dose reduction, or discontinuation, and no TRAE-related deaths occurred. Conclusions: In patients with stage IIIC1-IVA cervical cancer undergoing definitive concurrent chemoradiotherapy, the addition of ICIs may improve patient survival with manageable safety.

An open, prospective, single arm, phase II study of cadonilimab (PD-1/CTLA-4 bispecific antibody) with neoadjuvant chemotherapy in patients with advanced ovarian cancer: Interim analysis from the AK104-IIT-003 study.

e17552 Background: There is an unmet need to improve neoadjuvant chemotherapy (NAC) to decrease postoperative residual disease (R0 rate: 50%) and improve prognosis in ovarian cancer (OC). R0 rate and histopathological response of interval cytoreductive surgery (IDS) after NAC combined with immune checkpoint blockades were reported to be encouraging. Cadonilimab (AK104) is a tetravalent bispecific antibody targeting PD-1 and CTLA-4. In this study, we report the efficacy and safety of AK104 with NAC in patients with advanced-stage ovarian cancer (NCT05430906). Methods: This study is an open-label, prospective, single arm, phase II study of evaluating the efficacy and safety of cadonilimab combined with chemotherapy as neoadjuvant treatment for advanced ovarian cancer. Patients received neoadjuvant therapy of cadonilimab plus platinum-taxane chemotherapy (3 to 4 cycles) followed by surgery. Surgery would be performed within 30 days of completion of neoadjuvant therapy. The primary endpoint was the R0 rate. The secondary endpoints included objective response rate (ORR), disease control rate (DCR), chemotherapy response score (CRS), pathologic complete response(pCR), progression-free survival (PFS), and safety. A sample size of 35 achieves 80% power to detect a difference of 0.2 using a two-sided Z-test to estimate the standard deviation with a significance level (alpha) of 0.1. And the sample size was expected to be 40 cases to ensure that the FAS set contains 35 cases for analysis. Results: 17 patients were enrolled from Dec 12, 2022, to Dec 6, 2023. The median patient age was 57 years (range 45–70 years), and most patients presented with high-grade serous carcinoma (94.1%) and stage IVa (5.9%), IVb disease (76.5%). 15 (88.2%) patients had undergone IDS, with an R0 resection rate of 66.7%. ORR was 94.1%, with 1patient achieved CR and 15 patients achieved PR. 11.8% achieved pathological complete response, and 17.6% had a chemotherapy response score (CRS) of 3. PFS or OS data are not mature by cut-off date. Safety and adverse event (AE) were analyzed after completion of neoadjuvant therapy. Treatment-related AEs (TRAEs) of any grade were evaluated for all study populations. TRAEs of any grade occurred in 13 (76.5%) patients. Grade ≥3 TRAEs occurred in 3 (17.6%) patients. The most common TRAEs were thyroid dysfunction (23.5%) and bone marrow suppression (17.6%). Grade ≥ 3 irAE (immune⁃mediated colitis) occurred in 1 (5.9%) patient. All of the TRAEs, including severe AEs, were manageable, with no new safety concerns in this study. Conclusions: This study showed promising activity with a durable clinical response, supporting the potential of NAC with bispecific antibody AK104 in advanced-stage ovarian cancer. Meanwhile, long-term efficacy evaluation still needs following up. Clinical trial information: NCT05430906 .

Efficacy, safety and DNA methylation analysis of cadonilimab combined with taxane and cisplatin as the first-line treatment in patients with advanced esophageal squamous cell carcinoma (ESCC): An open-label, multicenter phase II trial– Updated results from AK104-IIT-014.

e16064 Background: Immune checkpoint inhibitors combined with chemotherapy has become the current first-line standard treatment for advanced ESCC, while still having a lot of room for improvements in objective responses and survival. Cadonilimab, a bispecific antibody simultaneously targeting PD-1 and CTLA-4, may further boost anti-tumour activity with a satisfied safety profile. Here, we present the updated data for the safety and efficacy of Cadonilimab combination therapy as the first-line treatment in advanced ESCC. Methods: Treatment-naïve patients (pts) with unresectable locally advanced or metastatic ESCC were eligible for inclusion. Cadonilimab (10mg/kg, iv, d1, q3w) combined with paclitaxel or nab-paclitaxel (175 mg/m2, iv, d1, q3w) and cisplatin (65 to 75 mg/m2, iv, d1, q3w) were administrated for up to 6 cycles, then Cadonilimab (10mg/kg, iv, d1, q3w) monotherapy continued as maintenance until progressive disease or unacceptable toxicity, with a maximum of 24 months. The primary endpoint was objective response rate (ORR). Secondary endpoints were progression-free survival (PFS), overall survival (OS), disease control rate (DCR) and safety. Plasma cell-free DNA samples were collected before and after treatment and prepared for DNA methylation level sequencing. Results: At updated analysis (cut-off: February 5, 2024), 35 pts were enrolled with a median age of 61 years (range 44-75), 82.9% were male, 57.1% had PD-L1 CPS<10 and 88.6% had distant metastases. In the efficacy-evaluable population (n = 29), 5 pts reached complete response (CR), 21 pts had partial response (PR) and 3 pts had stable disease (SD). The ORR was 89.7% (95%Cl: 71.5%-97.3%) and the DCR was 100.0% (95%Cl: 85.4%-100.0%). Among evaluable pts with PD-L1 CPS≥10 and PD-L1 CPS<10, the ORR were 100.0% (12/12) and 81.3% (13/16), respectively. SEPT9 methylation was significantly higher in patients with CR or PR compared to patients with SD (33.28% vs 3.87%, p < 0.001). The median PFS and OS was still not reached. Grade 3 or higher treatment-related adverse events (TRAEs) occurred in 9 (25.7%) pts. The most common TRAEs were neutropenia (17.1%), leukopenia (5.7%) and hyponatremia (5.7%). Immune-related adverse events were observed in 9 pts (25.7%). Three pts (8.6%) suffered from serious adverse events, and no grade 5 TRAEs or death were observed. Conclusions: The updated results suggested that bispecific antibody AK104 combined with taxane and cisplatin as first-line treatment showed promising anti-tumor activity and manageable safety in patients with advanced ESCC. DNA methylation level might be a potential biomarker for guiding patient outcomes. Follow-up is ongoing for survival analysis. Clinical trial information: NCT05522894 .

Phase 1b study of tarlatamab in de novo or treatment-emergent neuroendocrine prostate cancer (NEPC).

5012 Background: NEPC is an aggressive form of prostate cancer with poor prognosis and no standard treatment approach. NEPC can be characterized by late, treatment-emergent transformation from adenocarcinoma to high-grade neuroendocrine carcinoma (NEC), in 10–15% of mCRPC patients (pts). DLL3 is overexpressed in high-grade NECs, including NEPC, and minimally expressed on normal tissue. Tarlatamab, a bispecific T-cell engager immunotherapy with clinical activity in small cell lung cancer (SCLC), binds DLL3 and CD3 resulting in T-cell mediated tumor lysis. Here, we report primary analysis data of tarlatamab in NEPC (NCT04702737). Methods: This is an open-label phase 1b study evaluating tarlatamab monotherapy in adult (≥18 years [y]) pts with metastatic de novo or treatment-emergent NEPC by histologic, genomic, or immunohistochemistry (IHC) criteria. The starting dose was the highest safe and tolerable dose in the phase 1 SCLC trial (NCT03319940). Safety was the primary objective; anti-tumor activity and pharmacokinetics were secondary objectives. Exploratory analysis of DLL3 expression was assessed by IHC using the Ventana SP347 assay. Results: As of 28 March 2023, 40 pts received ≥1 tarlatamab dose (1 mg step dose, 100 mg target dose). Median (range) age was 64.5 (43–83) y, prior lines of therapy was 3 (1–9), prostate specific antigen at baseline was 0.2 (0.0–5000.0) μg/L. Treatment-related adverse events (TRAE) occurred in all patients, with no fatal TRAE. Most common TRAEs were cytokine-release syndrome (CRS; 65.0%), pyrexia (52.5%) and dysgeusia (42.5%). CRS occurred primarily in treatment cycle 1; events were mostly grade 1–2 (one grade 3 event). Treatment discontinuation due to TRAE was low (7.5%). Tarlatamab serum exposures were consistent with tarlatamab SCLC studies. Objective response rate (ORR) per Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST v1.1) was 10.5% (95% CI, 2.9, 24.8); median progression free survival (mPFS) was 1.9 months (m) (95% CI, 1.7, 3.5). Retrospective DLL3 IHC analysis showed that 18 of 32 (56.3%) biopsy evaluable pts had ≥1% DLL3 tumor positivity (DLL3+). As of 24 January 2024, ORR in DLL3+ pts was 22.2% (95% CI, 6.4, 47.6); durations of response in the 4 pts with response were 25.8 m, 9.2 m, 5.5 m, 3.7 m; mPFS in DLL3+ pts was 3.75 m (95% CI, 1.87, 11.01). Efficacy is shown in Table. Conclusions: Findings from this phase 1 study of tarlatamab in pts with NEPC demonstrated manageable safety with encouraging anti-tumor activity in DLL3 expressing NEPC. Further investigation is ongoing. Clinical trial information: NCT04702737 . [Table: see text]

Phase I dose escalation trial of the first-in-class TNFR2 agonist monoclonal antibody, HFB200301, in monotherapy and in combination with tislelizumab, an anti-PD-1 monoclonal antibody, in adult patients with advanced solid tumors.

2526 Background: Tumor necrosis factor receptor-2 (TNFR2) is expressed on effector CD8+, CD4+, and regulatory T (Treg) cells, natural killer (NK) cells, and myeloid cells. Activation of TNFR2 is anticipated to yield effective anti-tumor immunity by stimulating T-cell and NK-cell activation and proliferation in the tumor microenvironment. HFB200301 is a first-in-class anti-TNFR2 agonistic monoclonal antibody that triggers both innate and adaptive immune stimulation by binding to a specific epitope on TNFR2. We report initial results of an ongoing Phase I dose escalation, multicenter study (NCT05238883) of HFB200301 in monotherapy and in combination with tislelizumab (TIS) in patients (pts) with advanced refractory solid tumors. Methods: A Phase I trial designed to evaluate the safety, pharmacokinetics (PK), pharmacodynamics (PD), and initial efficacy of HFB200301 in monotherapy and in combination with TIS. Eligible pts, ≥18 years with an ECOG PS 0-1 and advanced solid tumors, will be enrolled in dose escalation at 5 different dose cohorts in monotherapy (Q4W), 3 different dose cohorts in combination with TIS (Q4W), or in dose expansion following determination of safety. Radiographic response is assessed every 8 weeks. Results: A total of 39 pts have been enrolled, 27 pts in monotherapy and 12 pts in combination. All pts received prior systemic therapy (median 2, range 1-4); 23 pts (59%) had prior checkpoint inhibitor treatment. No dose limiting toxicities were observed in either the monotherapy or combination arms. Treatment-related adverse events (TRAEs) occurred in 44% of monotherapy and in 50% of combination pts, with pruritis (11%), tremor (7%), fatigue (7%), asthenia (7%) and nausea (7%) being the most common TRAEs. No ≥ Grade 3 TRAEs were reported, and there were no drug discontinuations due to TRAEs. Preliminary HFB200301 PK analysis demonstrated non-linear clearance of HFB200301, with dose-proportional maximum concentration [Cmax], achieving sufficient exposures for peripheral target engagement in all tested doses. Emerging PD data demonstrates evidence of immune activation and expansion of CD8+ T cells, but not Tregs, in the tumor microenvironment and peripheral blood. Single cell RNAseq analysis of peripheral blood mononuclear cells demonstrated PD modulation in TNFR2 positive immune cell types post-HFB200301 treatment. Early response evaluation reveals ongoing durable clinical responses (> 6 months) in a PD-L1+ pleural mesothelioma pt and an EBV+ gastric cancer pt from combination cohorts. Conclusions: HFB200301 demonstrates a favorable safety profile, dose-dependent PK, with PD and preliminary clinical activity in monotherapy and in combination with TIS in pts with heavily pre-treated refractory solid tumors. Clinical trial information: NCT05238883 .

A phase II trial combining SHR-1316, bevacizumab, and cisplatin/carboplatin in patients with TNBC with active brain metastases.

e13133 Background: Triple-negative breast cancer (TNBC) has a high risk of brain metastases (BM), leading to poor survival. Treatment options for BMs are limited, and the combination of chemotherapy and immune checkpoint inhibitor is the standard-of-care for PD-L1 positive metastatic TNBC. Platinum-based systematic therapy is the mainstay of TNBC treatment and the addition of bevacizumab has shown improvement in the progression-free survival (PFS) of patients with BM. Therefore, this study aims to investigate the efficacy and safety of SHR-1316 (anti-PD-L1) in combination with bevacizumab and cisplatin/carboplatin in TNBC patients with BMs. Methods: In this single-center phase II trial, TNBC patients with active BM received SHR-1316, bevacizumab, and cisplatin/carboplatin. Prior treatment with bevacizumab or anti-PD-1/PD-L1 were not allowed. Prior platinum was allowed only in cases of previous platinum-sensitive response. The primary endpoint was objective response rate (ORR) of central nervous system (CNS), as assessed according to the response assessment in neuro-oncology brain metastases. The secondary endpoint included clinical benefit rate (CBR) of CNS, PFS, overall survival (OS), first progression site and safety. Results: As of January 12th, 2024, a total of 23 female patients with ECOG PS≥1(100%) were enrolled. The median number of previous lines of therapy for metastatic disease was 1 (0-3). All patients had active BM, of which 87% (20/23) were BM treatment-naïve and 13% (3/23) had BM progression after previous local therapy, 26.1% (6/23) had received a prior platinum agent. Of the 23 evaluable patients, the confirmed CNS ORR was 65.2% (95%CI: 42.7%-83.6%), with 3 complete response (CR), 12 partial response (PR), 7 stable disease (SD), and 1 progressive disease (PD). The median CNS-PFS was 11.2 months (95%CI, 5.8 to not reached), median PFS was 7.6 months (95%CI, 5.7-11.9), and median OS was 13.2 months (95%CI, 9.5 to not reached). Treatment-related adverse events (TRAEs) were reported in all 23 patients, and the most common TRAEs were neutrophil count decreased (69.6%, 16/23), anemia (65.2%, 15/23), asthenia (60.9%, 14/23), Hypomagnesaemia (56.5%, 13/23), leukopenia (52.2%, 12/23) and electrocardiogram T wave abnormal (52.2%, 12/23). The incidence of grade ≥3 TRAEs was 43.5% (10/23), including neutropenia (13%, 3/23), platelet count decreased (8.7%, 2/23), and hypertension (8.7%, 2/23). Only one patient had a grade 4 TRAE (lymphocytopenia), and SHR-1316 related serious adverse event (facial nerve disorder) occurred in only one patient. No grade 5 AEs were noted. Conclusions: SHR-1316 plus bevacizumab and cisplatin/carboplatin achieves a significant improvement in CNS ORR and brings PFS and OS benefits in TNBC patients with active BMs. As an effective and safe treatment, this triple-combination warrants further investigation. Clinical trial information: NCT04303988 .