Multitargeted Receptor Tyrosine Kinase Inhibitor Research Articles

Abstract PO2-05-01: Famitinib, a multi-targeted receptor tyrosine kinase inhibitor, combined with dalpicilib and fulvestrant in advanced HR-positive and HER2-negative breast cancer

Abstract Background: CDK4/6 inhibitors combined with endocrinotherapy (ET) represent an essential part of the treatment for HR-positive and HER2-negative breast cancer (BC). However, the role of angiogenesis inhibitors, such as bevacizumab, in these patients (pts) is controversial. While it has been demonstrated to improve progression-free survival (PFS), it has failed to show a significant overall survival (OS) benefit in HER2-negative BC. Several preclinical studies have explored the combination of anti-angiogenesis multi-targeted receptor tyrosine kinase inhibitors (TKIs) and CDK4/6 inhibitors in other cancers, suggesting a synergistic effect. Our phase Ib/II trial (NCT05176080, ChiCTR2100053950) aims to evaluate the safety and efficacy of a novel anti-angiogenesis TKI famitinib (F) added to dalpiciclib (D) and ET in advanced HR-positive and HER2-negative BC. Here we report the results of Phase Ib. Methods: A 3+3 de-escalation design was used in this dose-exploring phase (phase Ib). Pts with HR-positive and HER2-negative BC, who had no more than two prior chemotherapies in the advanced setting, were enrolled and administered F (orally, at doses of 15 mg/d, 10 mg/d, or 15 mg qod), D (orally, at doses of 150, 125 or 100 mg/d, 21 days on and 7 days off) and fulvestrant (intramuscularly, at a fixed dose of 500 mg every four weeks) until progression, unaccepted toxicities, or withdrawal. The initial dose level (Level 1) was set as F 15 mg daily and D 150 mg/d. The primary endpoints were recommended phase 2 dose (RP2D) and safety. Results: From December 2021 to June 2022, 18 pts were enrolled, and 3, 6, 3, and 6 pts were assigned to Level 1 (F 15 mg + D 150 mg), Level 2 (F 10 mg + D 125 mg), Level 3 (F 15 mg qod + D 125 mg), and Level 4 (F 10 mg + D 100 mg), respectively. 14 (77.8%) pts had visceral metastasis, and 7 (38.9%) had prior systemic therapies in the advanced setting. 13 (72.2%) pts had received ET, and 11 (61.1%) were resistant to ET before enrolled. A total of 6 dose-limiting toxicities (DLTs) were observed, including 3 Grade 4 thrombopenia (2 in Level 1, 1 in Level 2) and 3 Grade 4 neutropenia (2 in Level 3, 1 in Level 4), 4 of which were serious adverse events (AEs). The most common (≥20%) treatment-related AEs of Grade 3 or above were neutropenia (100.0%), leukopenia (88.9%), thrombocytopenia (33.3%), anemia (27.8%), lymphopenia and hypertension (both 22.2%). No death was reported. Overall 10 pts (55.6%) achieved confirmed partial responses and 16 (88.9%) achieved clinical benefits. Confirmed objective response rates (ORRs), clinical benefit rates (CBRs), and DLTs in different dose levels were shown in Table 1. Considering the efficacy and safety profiles, Level 4 was selected as RP2D. Conclusion: The anti-angiogenesis multi-targeted receptor TKI famitinib combined with CDK4/6i and fulvestrant has shown antitumor effects in advanced HR-positive and HER2-negative BC, and no new safety signals were observed. Citation Format: Min Yan, Mengwei Zhang, Limin Niu, Huimin Lv, Zhenzhen Liu, Huiai Zeng, Shengnan Zhao, Huihui Sun, Jing Wang, Yajing Feng, Huajun Li. Famitinib, a multi-targeted receptor tyrosine kinase inhibitor, combined with dalpicilib and fulvestrant in advanced HR-positive and HER2-negative breast cancer [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 PO2-05-01.

Anlotinib synergizes with venetoclax to induce mitotic catastrophe in acute myeloid leukemia

Venetoclax is a BCL2-targeted drug employed in treating various cancers, particularly hematologic malignancies. Venetoclax combination therapies are increasingly recognized as promising treatment strategies for acute myeloid leukemia (AML). In this study, we conducted an unbiased drug screen and identified anlotinib, a promising multi-targeted receptor tyrosine kinase inhibitor with oral activity currently utilized in the treatment of solid tumor, as a potent enhancer of venetoclax's anticancer activity in AML. Our investigation encompassed AML cell lines, primary cells, and mouse models, demonstrating effective low-dose combination therapy of anlotinib and venetoclax with minimal cytopenia or organ damage. Proteomic analysis revealed abnormal mitotic signals induced by this combination in AML cells. Mechanistically, anlotinib synergized with venetoclax by suppressing ARPP19 protein, leading to sustained activation of PP2A-B55δ. This inhibited AML cells from entering the mitotic phase, culminating in mitotic catastrophe and apoptosis. Additionally, we identified a specific synthetic lethal vulnerability in AML involving an ARPP19 mutation at S62 phosphorylation. These findings underscore the therapeutic potential of anlotinib and venetoclax combination therapy in AML, warranting further clinical investigation.

A Phase 2 Study of Sitravatinib in Combination with Nivolumab in Patients with Advanced or Metastatic Urothelial Carcinoma

Background and objectiveCheckpoint inhibitor therapy (CPI) has demonstrated survival benefits in urothelial carcinoma (UC); however, not all patients benefit from CPI due to resistance. Combining sitravatinib, a multitargeted receptor tyrosine kinase inhibitor of TYRO3, AXL, and MERTK (TAM) receptors and VEGFR2, with CPI may improve antitumor responses. Our objective was to assess the efficacy and safety of sitravatinib plus nivolumab in patients with advanced/metastatic UC. MethodsThe 516-003 trial (NCT03606174) is an open-label, multicohort phase 2 study evaluating sitravatinib plus nivolumab in patients with advanced/metastatic UC enrolled in eight cohorts depending on prior treatment with CPI, platinum-based chemotherapy (PBC), or antibody-drug conjugate (ADC). Overall, 244 patients were enrolled and treated with sitravatinib plus nivolumab (median follow-up 14.1–38.2 mo). Sitravatinib (free-base capsules 120 mg once daily [QD] or malate capsule 100 mg QD) plus nivolumab (240 mg every 2 wk/480 mg every 4 wk intravenously). Key findings and limitationsThe primary endpoint was objective response rate (ORR; RECIST v1.1). The secondary endpoints included progression-free survival (PFS) and safety. The Predictive probability design and confidence interval methods were used. Among patients previously treated with PBC, ORR, and median PFS were 32.1% and 3.9 mo in CPI-naïve patients (n = 53), 14.9% and 3.9 mo in CPI-refractory patients (n = 67), and 5.4% and 3.7 mo in CPI- and ADC-refractory patients (n = 56), respectively. Across all cohorts, grade 3 treatment-related adverse events (TRAEs) occurred in 51.2% patients and grade 4 in 3.3%, with one treatment-related death (cardiac failure). Immune-related adverse events occurred in 50.4% patients. TRAEs led to sitravatinib/nivolumab discontinuation in 6.1% patients. Conclusions and clinical implicationsSitravatinib plus nivolumab demonstrated a manageable safety profile but did not result in clinically meaningful ORRs in patients with advanced/metastatic UC in the eight cohorts studied. Patient summaryIn this study, the combination of two anticancer drugs, sitravatinib and nivolumab, resulted in manageable side effects but no meaningful responses in patients with bladder cancer.

Potential therapeutic target secretogranin II might cooperate with hypoxia-inducible factor 1α in sunitinib-resistant renal cell carcinoma.

Multitargeted receptor tyrosine kinase inhibitors, including vascular endothelial growth factor (VEGF) inhibitors, such as sunitinib, have been used as the primary targeted agents for patients with recurrent or distant metastasis of advanced renal cell carcinoma (RCC). However, endogenous or acquired sunitinib resistance has become a significant therapeutic problem. Therefore, we focused on mechanisms of sunitinib resistance in RCC. First, we undertook RNA sequencing analysis using previously established sunitinib-resistant RCC (SUR-Caki1, SUR-ACHN, and SUR-A498) cells. The results showed increased expression of secretogranin II (SCG2, chromogranin C) in SUR-RCC cells compared to parental cells. The Cancer Genome Atlas database showed that SCG2 expression was increased in RCC compared to normal renal cells. In addition, the survival rate of the SCG2 high-expression group was significantly lower than that of the RCC low-expression group. Thus, we investigated the involvement of SCG2 in sunitinib-resistant RCC. In vitro analysis showed that migratory and invasive abilities were suppressed by SCG2 knockdown SUR cells. As SCG2 was previously reported to be associated with angiogenesis, we undertook a tube formation assay. The results showed that suppression of SCG2 inhibited angiogenesis. Furthermore, coimmunoprecipitation assays revealed a direct interaction between SCG2 and hypoxia-inducible factor 1α (HIF1α). Expression levels of VEGF-A and VEGF-C downstream of HIF1α were found to be decreased in SCG2 knockdown SUR cells. In conclusion, SCG2 could be associated with sunitinib resistance through VEGF regulation in RCC cells. These findings could lead to a better understanding of the VHL/HIF/VEGF pathway and the development of new therapeutic strategies for sunitinib-resistant RCC.

Activity of cabozantinib (CABO) plus durvalumab (DURVA) in patients (pts) with advanced urothelial carcinoma (UC) or non-UC variant histologies (VH) after platinum chemotherapy: Interim results from the phase 2 ARCADIA trial.

4578 Background: Combining multitargeted receptor tyrosine kinase inhibitor (TKI) with checkpoint inhibitors has shown synergistic effect in pts with UC due to the immunomodulatory propriety of VEGFR inhibitors. We investigated if the combination of CABO and DURVA in pts with advanced UC and non-UC histology (VHs) in a phase II study (NCT03824691). Herein the preliminary results of the interim analysis. Methods: Patients affected by UC and VHs recurred or progressed after failure of at least one line of platinum-based chemotherapy for metastatic disease have been treated with CABO 40 mg daily, orally, and are administered DURVA 1500 mg IV, q28 days, until disease progression (PD, by RECIST 1.1) or onset of unacceptable toxicity. Key inclusion criteria were ECOG-PS 0-1 and adequate organ function. Response was evaluated by RECIST criteria v.1.1 every 8 wks. The primary endpoint of the study was OS. Secondary endpoints included safety (CTCAE v.4.03), objective response-rate (ORR), duration of response (DoR), progression-free survival (PFS). The assumption was to detect an improvement in the median OS from ≤6 months (H0) to ≥9 months (H1). Results: Between September 2019 and February 10, 2023, the ARCADIA study enrolled 63 pts: this interim analysis was performed after obtaining at least one post-baseline tumor assessment data from 58 pts. The median follow-up was 23.5 mos (interquartile [IQ] range: 7.7-27.7mos): 27% were female, the median age was 64 yrs (range: 42-81), 20 pts (34%) had a pure/predominant non-UC VH: 9 (45%) a squamous differentiation/sarcomatoid tumor, 5 (25%) an adenocarcinoma, 4 (20%) a small-cell neuroendocrine tumor, 1 (5%) a clear-cell tumor, and 1 a nested VH (5%). Eleven pts (19%) had received ≥2 prior systemic anticancer therapies. In 58 response-evaluable pts, 12 (20%) complete responses (CR) and 11 partial responses (PR) were obtained, the ORR being 39.7% (95%CI: 27.1-53.4) and disease control rate was 69% (95%CI: 55.5-80.5). In the cohort of pts with VH, the ORR was 45% (95%CI: 23.1-68.5). Median PFS was 7.6 mos (95%CI: 4.6-13-6 mos) and median OS was 11.6 (95% CI 6.8-20.3 months). Median exposure of treatment was 4.8 mos; 35 pts (55.5%) of 63 pts had all-grade treatment-related adverse events (AE) and 4 pts (6.3%) reported grade 3 (treatment related) AE with no grade 3-5 events. Dose-reductions of CABO were needed in 25 pts (39%). No treatment-related deaths were reported. Conclusions: CABO in combination with DURVA showed promising preliminary activity with a manageable safety profile in pts with advanced UC and in non-UC VH after previous chemotherapy exposure, deserving further evaluation of the combination that is ongoing with ARCADIA and other clinical trials. More mature results with longer follow-up will be presented. Clinical trial information: NCT03824691 .

The combination therapy of anlotinib and penpulimab for the treatment of small cell lung cancer after platinum-based chemotherapy: Results of a phase II exploratory study.

e20628 Background: Anlotinib is a multi-target receptor tyrosine kinase inhibitor that has been developed in China. It works by inhibiting various kinases involved in angiogenesis and tumor cell proliferation, including VEGFR, FGFR, PDGFR, and c-Kit. The results of the Phase II ALTER1202 trial showed that patients who received anlotinib as a third-line or later treatment after failing at least two chemotherapy regimens had a better progression-free survival (PFS) and overall survival (OS) compared to those who received placebo. In light of these results, the combination of anlotinib and penpulimab (a novel PD-1 inhibitor) is being studied as a second-line treatment for small cell lung cancer patients who failed first-line chemotherapy with platinum-containing drugs. Methods: This open-label, single-arm, multi-center, Phase II exploratory study (NCT050019710) enrolled patients with small cell lung cancer who had previously received platinum-based chemotherapy. Participants were given 200mg of penpulimab every three weeks and 10mg of anlotinib daily, with a two-week on and one-week off schedule, until disease progression, unacceptable toxicity, or study discontinuation. The primary objective of the study was to evaluate the antitumor activity of the combination therapy using the objective response rate (ORR) as measured by RECIST v1.1. Secondary objectives included evaluating the disease control rate (DCR), PFS, OS, and the safety and tolerability of the combination therapy. Results: As of January 31, 2023, 21 patients (median age 58 years, with 66% having ECOG performance status of 0 or 1, 95% being male) had been enrolled and received treatment. Of these, 18 patients were evaluable for RECIST and had an ORR of 33.33% (6/18) and a DCR of 77.78% (14/18). The median PFS was 5.934 months with a 6-month PFS rate of 33.33%. The median duration of response was 8 months. Nineteen of the 21 patients (90%) experienced treatment-related adverse events, with 4 patients (21%) experiencing grade 3 or higher adverse events. The most common adverse events related to anlotinib were hepatic injury, hematotoxicity, and hypertension. Conclusions: The combination of penpulimab and anlotinib showed promising clinical benefits and a favorable safety profile in small cell lung cancer patients who failed first-line platinum-based chemotherapy. Clinical trial information: NCT05001971 .

Efficacy of salvage therapies after failure of adjuvant anti-PD-1 monotherapy for melanoma in the Chinese population: a multi-institutional cohort study

SummaryThe majority of melanoma patients experience relapse during adjuvant therapy or after the end of therapy. Sixty-one patients from 3 melanoma centres who experienced recurrence and received adjuvant pembrolizumab for resected stage III/IV melanoma were enrolled. Disease characteristics, recurrence characteristics, subsequent management and outcomes were retrospectively analysed. Sixty-one patients were enrolled in this study. The median time to first relapse from the commencement of adjuvant pembrolizumab was 8 months (1–22 months). The first recurrences were locoregional alone in 25 patients (41%), distant alone in 29 (47.5%) and concurrent locoregional and distant relapse in 7 (11.5%). At the first recurrence, 4 patients (80%) who underwent resection alone experienced further relapse of disease. Three (60%) patients who were treated with adjuvant pembrolizumab following surgery, 2 (100%) patients who were treated with adjuvant chemotherapy, 2 (66.7%) patients who were treated with adjuvant chemotherapy and pembrolizumab combined and 3 (100%) patients who were treated with adjuvant radiotherapy and pembrolizumab combined had further recurrence. Of the three patients treated with adjuvant BRAF/MEKi following the first relapse, none had yet recurred. Of the 8 patients treated with pembrolizumab alone, only one patient (12.5%) who recurred after ceasing adjuvant PD1 had a partial response. The overall response rate to BRAF/MEKi was 75%, 3/4; to pembrolizumab in combination with an oral multitargeted receptor tyrosine kinase inhibitor, it was 22.2%, 2/9; to chemotherapeutic agents alone, it was 33.3%, 1/3; and to chemotherapeutic agents combined with pembrolizumab, it was 37.5%, 3/8. The patient treated with imatinib had progressive disease after 3 months of treatment. Of the 6 patients who received temozolomide combined with pembrolizumab, 3 (3/6, 50%) had a partial response. The median OS of the patients who relapsed locoregionally only was longer than that of the patients who relapsed distally at the first recurrence (35 months and 14 months, respectively; P < 0.01). The outcomes of the patients with disease recurrence during or after the completion of 1 year of adjuvant anti-PD1 therapy were poor despite multimodality treatment.

Abstract 4811: Oxygen tension - dependent differences in cancer cell kinome

Abstract Current approaches to preclinical cancer research often fail to consider the impact of ambient oxygen (O2; ~21%) on cancer cells. This is also true for hypoxia studies that typically involves cancer cells previously grown in ambient O2 before subsequent transfer to hypoxia. However, the tumor microenvironment is characterized by significantly lower O2 levels. We have previously demonstrated the impact of ambient O2 on stem cell populations, signaling pathways and resistance to therapy. We developed an experimental approach that allows us to collect and process tumor tissues from transgenic mammary tumor mouse models and ovarian cancer patients under physioxia (3% O2), such that they are never exposed to ambient O2. In this study, our goal was to explore oxygen-dependent signaling pathway alterations and to determine how these pathways are influenced by targeted drugs in the context of physioxia or ambient air (AA). Our studies revealed increased basal phosphorylation levels of EGFR (Y1068) in the tumor cells in AA, relative to physioxia. However, downstream signaling effectors AKT and ERK showed higher phosphorylation levels under physioxia, compared to AA, suggesting that their activation is independent of EGFR signaling. These findings correlate with the decreased sensitivity of the tumor cells under physioxia to target drugs lapatinib and alpelisib. We then sought to examine basal and target drug induced kinome changes in tumor cells under physioxia and AA via Multiplexed Inhibitor Beads (MIBs) kinome assay. This assay revealed significant differences in the kinome of the tumor cells under physioxia compared to AA. Although direct comparison between vehicle and lapatinib treated cells in physioxia and ambient air showed very minimal changes, pairwise comparison between lapatinib treated physioxia cells and vehicle treated AA cells revealed an increase in the activity of PDGFRB in lapatinib treated physioxia cells. Similarly, a receptor tyrosine kinase (RTK) array and western blotting showed increased basal and lapatinib induced phosphorylation of PDGFRB (Y751) under physioxia. Next, we determined the potential role of PDGFRB in downstream signaling pathway activation of AKT and ERK and resistance to lapatinib. We found that sunitinib, a multitarget RTK inhibitor with high affinity for PDGFR effectively decreased PGDFRB activity under physioxia, with a concurrent decrease in the phosphorylation of AKT. Moreover, tumor cells under physioxia were more sensitive to sunitinib treatment, relative to ambient air. Furthermore, a combination of lapatinib and sunitinib rendered tumor cells under physioxia more sensitive to treatment than with lapatinib alone. These findings suggest that ambient and physioxic oxygen tensions differentially impact cancer relevant signaling pathways. Therefore, it may be necessary to carry out preclinical cancer studies in the context of physiologically relevant oxygen tensions to aid translatability. Citation Format: Adedeji K. Adebayo, Brijesh Kumar, Christopher Davis, Steven P. Angus, Harikrishna Nakshatri. Oxygen tension - dependent differences in cancer cell kinome. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4811.

Radiotherapy opens the blood–brain barrier and synergizes with anlotinib in treating glioblastoma

BackgroundGlioblastoma (GBM) has a poor prognosis and lacks effective treatment. Anlotinib is a multitargeted receptor tyrosine kinase inhibitor (TKI) that may have anti-tumor activity in the central nervous system (CNS). This study aimed to determine the therapeutic value of radiotherapy combined with anlotinib in GBM via preclinical research. MethodsHPLC-MS/MS was used to assess the concentration of anlotinib in blood and brain samples. Cell proliferation assays, flow cytometry, and colony formation assays were performed in vitro. The potential value of anlotinib or in combination with radiotherapy for GBM treatment was estimated in vivo. Western blotting, immunohistochemistry, and immunofluorescent staining were performed to determine the underlying mechanism. ResultsAnlotinib effectively inactivated the JAK3/STAT3 pathway to inhibit growth and induce apoptosis in malignant glioma cells (MGCs) independent of MGMT expression. Meanwhile, anlotinib induces MGCs G2/M arrest and sensitizes MGCs to radiation. Radiation down-regulates claudin-5 and weakens the blood–brain barrier (BBB), which contributes to the increased distribution of anlotinib in the CNS by 1.0–2.9 times. Anlotinib restrains tumor growth (PCNA), inhibits tumor microvascular proliferation (CD31), and alleviated intratumor hypoxia (HIF 1α) in vivo. Anlotinib alone or in combination with radiation is effective and safe in vivo evaluation. ConclusionsWe discovered that anlotinib, the original small molecule antiangiogenesis TKI, down-regulates JAK3/STAT3 axis with anti-cancer activity alone or in combination with radiation. Anlotinib combined with radiotherapy might be a promising treatment for newly diagnosed GBM in the clinic.

Raltitrexed enhanced antitumor effect of anlotinib in human esophageal squamous carcinoma cells on proliferation, invasiveness, and apoptosis

BackgroundAnlotinib is a multi-targeted receptor tyrosine kinase inhibitor (TKI) which has exhibited encouraging clinical activity in advanced non-small cell lung cancer (NSCLC) and soft tissue sarcoma. Raltitrexed is well known to be effective in the treatment of colorectal cancer in China. The present study aims to investigate the combinatory antitumor effect of anlotinib and raltitrexed on human esophageal squamous carcinoma cells and further explore the molecular mechanisms in vitro.MethodsHuman esophageal squamous cell lines KYSE-30 and TE-1 were treated with anlotinib or raltitrexed, or both, then cell proliferation was measured by MTS and colony formation assay; cell migration and invasion were detected by wound-healing and transwell assays; cell apoptosis rate was studied by flow cytometry and the transcription of apoptosis-associated proteins were monitored by quantitative polymerase chain reaction (qPCR) analysis. Finally, western blot was performed to check phosphorylation of apoptotic proteins after treatment.ResultsTreatment with raltitrexed and anlotinib showed enhanced inhibitory effects on cell proliferation, migration and invasiveness compared with raltitrexed or anlotinib monotherapy. Meanwhile, raltitrexed combined with anlotinib strongly increased cell apoptosis percentage. Moreover, the combined treatment down-regulated mRNA level of the anti-apoptotic protein Bcl-2 and invasiveness-associated protein matrix metalloproteinases-9 (MMP-9), while up-regulated pro-apoptotic Bax and caspase-3 transcription. Western blotting showed that the combination of raltitrexed and anlotinib could inhibit the expression of phosphorylated Akt (p-Akt), Erk (p-Erk) and MMP-9.ConclusionsThis study indicated that raltitrexed enhanced the antitumor effects of anlotinib on human ESCC cells by down-regulating phosphorylation of Akt and Erk, providing a novel treatment option for patients with esophageal squamous cell carcinoma (ESCC).

Abstract P4-01-24: Targeting receptor tyrosine kinases in overcoming tamoxifen resistance and dormancy in invasive lobular cancer

Abstract Objective: The molecular hallmark of invasive lobular cancer (ILC) is the loss of E-cadherin, resulting in the unique morphology, low mitotic index and unusual metastatic spread to ovaries, gut, and peritoneum. Patients with ILC face delayed, and higher stage at diagnosis, worse disease-free and overall survival1. The most frustrating challenge is the delayed recurrence, likely due to resistance and induction of dormancy2. Despite these unique features, ILC is lumped with hormone receptor-positive invasive ductal cancers (IDC); consequently, management strategies are based on data from IDC. Hence there is an unmet need to address the unique challenges of ILC. We generated Tamoxifen-resistant (TAMR) ILC cell lines with the aim to study the distinct characteristics, dormancy, differentially activated pathways, and response to drugs targeting such pathways in the resistant cells. Methods: We used MDA-MB-134-VI and SUM44-PE cells to study the effect of tamoxifen in combination with multi-targeted receptor tyrosine kinase inhibitor, Lenvatinib. TAMR cells from both MB-134 and SUM44PE cells were generated by growing them in increasing concentrations of 4-hydroxy tamoxifen (4-HT) up to 500nM, for 6 months. Total RNA from parental and TAMR cells were subjected to RNA-seq. Whole cell extracts were analyzed for specific phospho proteins by Western Blot analysis. Growth kinetics and effect of drugs on cell viability was measured using MTT assay (Roche). Cell migration was measured using Transwell migration assay. Novel engineered 2D and 3D cultures were used to study dormancy and the effect of the drug combination. Orthotopic tumor induction in NSG mice is ongoing to determine the effect of drug combination in vivo. Results: The TAMR cell lines show distinct morphological features, small but significant increase in growth rate (p=0.05) and remarkably higher migration (MB-134TAMR:11.5-fold, p&amp;lt; 0.005 and SUM44TAMR:&amp;gt;100-fold, p&amp;lt; 0.005). The IC50 for tamoxifen increased from 8.1M (MB-134) to 16.8M (MB-134TAMR) and from 11.3 M (SUM44) to 26.6 M (SUM44TAMR). RNA seq analysis revealed enrichment of PI3K-AKT, MAPK, cAMP, Rap1 signaling pathways, ECM-receptor interaction, Focal adhesion, and steroid hormone biosynthesis pathways in the TAMR cells. Upon stimulation by endothelial growth factor, the MB-134TAMR but not the parental cells showed dose dependent increase in phospho-AKT and phospho-MAPK levels. Using novel 2D/3D cultures, we show differential morphologies between IDC (MCF7) cells, MB-134TAMR, and the parental cells. MCF7 and MB-134TAMR cells are more adherent to fibronectin (p&amp;lt; 0.0001), whereas the parental ILC cells are more adherent to COL3A1 (p&amp;lt; 0.0001), a feature observed in dormancy3. Further, the administration of 5 M 4-HT induced a cessation of growth in the parental cell line, with a sub-population of apparent dormant cells. The combination of Lenvatinib (5 M) and 4-HT (7.5 M) synergistically inhibited both the parental cell lines by ~60%. Lenvatinib (5 M) and 4-HT (15 M) inhibited the MB-134TAMR and SUM44TAMR cell lines synergistically by 65% and 45% respectively. In vivo, the growth of MB-134 induced tumors were completely suppressed when 5mg sustained release pellet of TAM citrate was injected in the subscapular region of tumor bearing mice (tumor @100cm3). The results of the combination using in vivo models and 2D/3D cultures will be reported. Conclusion and significance: Lenvatinib with tamoxifen is active and synergistic against parental and TAMR ILC cell lines. Our novel 2D/3D cultures show distinct pattern of growth for ILC cells and a possible induction of a dormant subpopulation upon 4-HT treatment. Overcoming resistance to conventional therapies and preventing induction of dormancy will improve long-term outcomes of patients with ILC. 1. PMID:33641217 2. PMID: 34388695 3. PMID: 35121989 Citation Format: Bhuvaneswari Ramaswamy, Nikhil Pramod, Anagh Kulkarni, Xilal Y. Rima, Eduardo Reátegui, Eswar Shankar, Sarmila Majumder. Targeting receptor tyrosine kinases in overcoming tamoxifen resistance and dormancy in invasive lobular cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-01-24.

Berbamine dihydrochloride suppresses the progression of colorectal cancer via RTKs/Akt axis

Ethnopharmacological relevanceBerberis amurensis Rupr. is used to treat cancer as a traditional herbal medicine. Berbamine (BBM) is a natural bisbenzylisoquinoline alkaloid extracted from Berberis amurensis which possesses multiple pharmacological activity including anticancer. Aim of the studyTo investigate the influence of BBM on the progression of colorectal cancer (CRC) and further explore the underlying mechanism of BBM based on the RTKs/Akt signaling pathway. Materials and methodsIn vitro, cell viability and colony formation were conducted to detect BBM inhibitory of CRC cell lines. Transwell was detected the ability of migration and invasion by BBM. Apoptosis detection assay, cell cycle assay and the measurement of ROS were detected to confirm the inductive effect of cell apoptosis. RT-qPCR and Western blot to clarify the specific mechanism of anticancer. Finally, we conducted HE staining, Ki67, Tunnel and immunochemistry were confirmed the anti-colorectal cancer activity of BBM from vivo study. ResultsWe found that BBM could inhibit CRC cell lines growth. Moreover, BBM presented an inhibitory effect the ability of migration and invasion in CRC cells. Furthermore, the occurrence of apoptosis was involved in the anti-colorectal cancer role of BBM. BBM also triggered ROS accumulation in CRC cells that might be a key factor for the inductive effect of BBM in cell apoptosis. Cell cycle assay revealed that BBM induced the arrest of G1-S phase and increased the p21 levels but decreased CyclinE1, CyclinE2, CDK6, CyclinD1. RT-qPCR manifested that the down-regulation effect of BBM on AKT1, EGFR, PDGFRα and FGFR4 genes. The results also showed that BBM could decreased the expression levels of phosphor-AKT, PDGFRα, PDGFRβ, EGFR, FGFR3 and FGFR4 which belong to RTKs family. Consistently, BBM remarkably suppressed tumor xenograft growth in nude mice. ConclusionTaken together, all the results as presented above suggest that BBM as a novel multitargeted receptor tyrosine kinase inhibitor plays a crucial role in the inhibitory effect of CRC and may be a promising therapeutic agent for the CRC in clinic.

Prospective Evaluation of Sorafenib Combined with Chemotherapy in Newly Diagnosed Adult Core-Binding Factor Acute Myeloid Leukemia: An Open-Label, Randomized Controlled, Multicenter Phase II Trial

Objective Core-binding factor acute myeloid leukemia (CBF-AML) includes AML with t(8;21)(q22;q22) and inv(16)(p13q22)/t(16;16)(p13;q22) chromosomal rearrangements, leading to the RUNX1-RUNX1T1 and CBFB-MYH11 fusion genes, respectively. Although CBF-AML is considered to have a favorable prognosis relative to other AML subtypes, up to 40% of these patients experience relapse. Recent studies demonstrate achievement of complete molecular remission (CMR) at the end of treatment significantly associated with a reduced risk of relapse. A high frequency of mutations and/or high expression of KIT gene is observed in CBF-AML. Sorafenib is a first-generation type-II multitargeted tyrosine kinase receptor inhibitor (TKI) that suppresses various signaling pathways associated with the development of AML, such as RTK (FLT3, c-KIT). Thus the purpose of this study is to evaluate the safety and efficacy of sorafenib combined with chemotherapy in adult newly diagnosed CBF-AML. Methods Patients were randomly assigned (1:1) to control group (chemotherapy alone) or sorafenib group (sorafenib combined with chemotherapy). For control group, patients received one cycle of induction therapy with idarubicin (12 mg/m² on days 1-3) plus cytarabine (100 mg/m² on days 1-7), followed by one cycle of idarubicin (8 mg/m² on days 1-3) plus cytarabine (2 g/m² q12h on days 1-3) and two cycles of high-dose cytarabine consolidation therapy (2 g/m² q12h on days 1-3). For sorafenib group, patients were treated with chemotherapy plus sorafenib at 400 mg twice daily on days 8-21 for induction cycle, and on days 1-21 for each consolidation, and as maintenance for 12 months. Allogeneic or autologous HSCT were implemented based on the measurable residual disease (MRD) level and donor availability after 4 cycles of therapy. MRD levels were serially monitored for RUNX1-RUNX1T1 or CBFB-MYH11 transcripts by real-time quantitative polymerase chain reaction. Results were expressed as a [fusion gene/ABL1] ×100 transcript ratio. Major molecular response (MMR) and complete molecular remission (CMR) are defined as transcript ratio < 0.1% and 0.001%, respectively. The primary endpoint was CMR after 4 cycles of therapy in bone marrow (BM). Results Between January 2020 and March 2022, 64 patients were enrolled and randomly assigned to sorafenib group (n=32) or control group (n=32). There is no significant difference between the two groups about age, gender, CBF subtype, BM blast percentage, additional chromosome abnormalities and gene mutations at diagnosis. The hematological complete remission in the sorafenib and control group were 96.9% and 94.1%, respectively (p=.592). Following three cycles of therapy, MMR was observed in 79.3% of the sorafenib group and 46.9% of the control group (p =.009). Sorafenib group also had a significantly higher CMR than control group (62.1% vs 28.1%, p =.009). After four cycles of therapy, MMR increased to 100% in the sorafenib group and 70.8% in the control group (p =.019), whileCMR was also more frequently achieved in the sorafenib group than that in the control group (90.9% vs 54.2%, p =.006). There was no significant difference of grades 3-4 adverse events between the two groups. Grade 4 neutropenia (neutrophil count less than 0.5×10⁹ cells per L) and thrombocytopenia (platelet count less than 20×10⁹ per L) were observed in all cases. The median duration of neutropenia was 12d (range, 6-25d) in the sorafenib group and 10d (range, 5-22d) in the control group (p =.063) , while the median duration of thrombocytopenia was 12d (range, 5-33d) and 9d (range, 6-19d) (p =.052), respectively.The most common grade 3-4 non-hematological adverse events in sorafenib and control group were pneumonia (31.3% vs 57.4%, p=.019), mucositis (21.9% vs 24.1%, p =.816), blood stream infection (37.5% vs 31.5%, p =.568). Conclusion Sorafenib combined with chemotherapy significantly increased the CMR after 4 cycles of therapy, however, the incidence of haematological and non-haematological adverse events did not apparently increased. The impact of sorafenib combined with chemotherapy on relapse and survival of CBF-AML need further following-up. Keywords: Sorafenib, CBF-AML, CMR, adverse events

Escape from breast tumor dormancy: The convergence of obesity and menopause

Obesity is associated with an increased risk of, and a poor prognosis for, postmenopausal (PM) breast cancer (BC). Our goal was to determine whether diet-induced obesity (DIO) promotes 1) shorter tumor latency, 2) an escape from tumor dormancy, and 3) an acceleration of tumor growth and to elucidate the underlying mechanism(s). We have developed invitro assays and PM breast tumor models complemented by a noninvasive imaging system to detect vascular invasion of dormant tumors and have used them to determine whether obesity promotes the escape from breast tumor dormancy and tumor growth by facilitating the switch to the vascular phenotype (SVP) in PM BC. Obese mice had significantly higher tumor frequency, higher tumor volume, and lower overall survival compared with lean mice. We demonstrate that DIO exacerbates mammary gland hyperplasia and neoplasia, reduces tumor latency, and increases tumor frequency via an earlier acquisition of the SVP. DIO establishes a local and systemic proangiogenic and inflammatory environment via the up-regulation of lipocalin-2 (LCN2), vascular endothelial growth factor (VEGF), and basic fibroblast growth factor (bFGF) that may promote the escape from tumor dormancy and tumor progression. In addition, we show that targeting neovascularization via a multitargeted receptor tyrosine kinase inhibitor, sunitinib, can delay the acquisition of the SVP, thereby prolonging tumor latency, reducing tumor frequency, and increasing tumor-free survival, suggesting that targeting neovascularization may be a potential therapeutic strategy in obesity-associated PM BC progression. This study establishes the link between obesity and PM BC and, for the first time to our knowledge, bridges the dysfunctional neovascularization of obesity with the earliest stages of tumor development.

Phosphoproteomic Analysis Identifies TYRO3 as a Mediator of Sunitinib Resistance in Metastatic Thymomas.

Simple SummaryAfter initially responding to empiric radio-chemotherapy, most advanced thymomas and thymic carcinomas become refractory and require second-line therapies. The multi-target tyrosine kinase inhibitor, sunitinib, is one of few options, especially in patients with thymic carcinomas, and has resulted in partial remissions and prolonged overall survival. However, sunitinib shows limited activity, and not all patients benefit equally. A better understanding of its mode of action and the definition of predictive biomarkers would help select patients who profit most. Using a real-time multiplex tyrosine phosphorylation assay containing 144 kinase substrates in a defined set of sunitinib-sensitive and -resistant cell lines, we generated a sunitinib response index (SRI). Protein lysates from thymomas and thymic carcinomas with spike-in of sunitinib were then classified as potential responders vs. non-responders using the same SRI classifier. Bioinformatic prediction and further experimental analysis of activated upstream kinases identified TYRO3 as a potent mediator of sunitinib resistance, specifically in metastatic thymomas. TYRO3 could serve both as a biomarker of sunitinib resistance and a potential therapeutic target that could help to tailor treatment decisions and to overcome therapy resistance in advanced thymomas and thymic carcinomas.Background: After initially responding to empiric radio-chemotherapy, most advanced thymomas (TH) and thymic carcinomas (TC) become refractory and require second-line therapy. The multi-target receptor tyrosine kinase (RTK) inhibitor, sunitinib, is one of the few options, especially in patients with thymic carcinomas, and has resulted in partial remissions and prolonged overall survival. However, sunitinib shows variable activity in thymomas, and not all patients benefit equally. A better understanding of its mode of action and the definition of predictive biomarkers would help select patients who profit most. Methods: Six cell lines were treated with sunitinib in vitro. Cell viability was measured by MTS assay and used to define in vitro responders and non-responders. A quantitative real-time assay simultaneously measuring the phosphorylation of 144 tyrosine kinase substrates was used to correlate cell viability with alterations of the phospho-kinome, calculate a sunitinib response index (SRI), and impute upstream tyrosine kinases. Sunitinib was added to protein lysates of 29 malignant TH and TC. Lysates were analyzed with the same phosphorylation assay. The SRI tentatively classified cases into potential clinical responders and non-responders. In addition, the activation patterns of 44 RTKs were studied by phospho-RTK arrays in 37 TH and TC. Results: SRI application separated thymic epithelial tumors (TET) in potential sunitinib responders and resistant cases. Upstream kinase prediction identified multiple RTKs potentially involved in sunitinib response, many of which were subsequently shown to be differentially overexpressed in TH and TC. Among these, TYRO3/Dtk stood out since it was exclusively present in metastatic TH. The function of TYRO3 as a mediator of sunitinib resistance was experimentally validated in vitro. Conclusions: Using indirect and direct phosphoproteomic analyses to predict sunitinib response in malignant TET, we have shown that TH and TC express multiple important sunitinib target RTKs. Among these, TYRO3 was identified as a potent mediator of sunitinib resistance activity, specifically in metastatic TH. TYRO3 may thus be both a novel biomarker of sunitinib resistance and a potential therapeutic target in advanced thymomas and thymic carcinomas.

EP08.02-081 Cabozantinib Plus Atezolizumab in First or Second-Line Advanced NSCLC and Previously-Treated EGFR Mutant Advanced NSCLC

Cabozantinib, a multitargeted receptor tyrosine kinase inhibitor (TKI), promotes an immune-permissive environment that may enhance immune checkpoint inhibitor (ICI) activity. COSMIC-021 (NCT03170960) is a multicenter phase 1b study evaluating cabozantinib plus atezolizumab in advanced solid tumors. In COSMIC-021, cabozantinib plus atezolizumab demonstrated encouraging clinical activity in a cohort of patients with advanced NSCLC (aNSCLC) previously treated with ICIs (Neal. ASCO 2020. Abstr 9610).

Efficacy and safety of anlotinib combined with carboplatin and pemetrexed as first-line induction therapy followed by anlotinib plus pemetrexed as maintenance therapy in EGFR/ALK wild-type advanced non-squamous non-small cell lung cancer in China: a multicenter, single-arm trial.

BackgroundThe efficacy and safety of chemotherapy strategies combining the multi-target receptor tyrosine kinase inhibitor in patients with advanced EGFR/ALK wild-type non-squamous non-small-cell lung cancer (nsq-NSCLC) are undetermined. We aimed to investigate the efficacy and safety of anlotinib combined with carboplatin/pemetrexed-based chemotherapy followed by maintenance therapy (anlotinib plus pemetrexed) in advanced EGFR/ALK wild-type nsq-NSCLC.MethodsEligible patients with wild-type EGFR/ALK advanced nsq-NSCLC who received first-line therapy in Henan Province from March 2019 to February 2021 were recruited. All patients were treated with anlotinib in combination with carboplatin/pemetrexed-based chemotherapy, followed by maintenance therapy (anlotinib plus pemetrexed). The primary endpoint was progression-free survival (PFS). The secondary endpoints included overall survival (OS), disease control rate (DCR), objective response rate (ORR), and adverse events (AEs). Response and AEs were assessed based on the Response Evaluation Criteria in Solid Tumors (1.1) and National Cancer Institute - Common Terminology Criteria for Adverse Events v.4.0.3, respectively. The follow-up interval for survival was 6 weeks and the safety follow-up was performed until the end of treatment. Kaplan-Meier analysis was used to calculate the median PFS and OS.ResultsThirty-eight participants with median age of 62 (range, 33–75) years were evaluated. Five participants were still on maintenance therapy until the end of the study. The majority were non-smokers (68.4%). The median follow-up was 13.6 (range, 12.3–14.9) months. The median PFS (mPFS) was 10.5 (95% CI: 4.1, 17.0) months, and the median OS was 23.4 [95% CI: not evaluable (NE), NE] months. The DCR and ORR were 94.7% and 60.5%, respectively. Grade 3 and above treatment-related adverse events (TRAEs) happened to 12 participants. The most common TRAEs were hypertension (23.7%), neutropenia (19.4%), and bone marrow toxicity (10.5%). Seven patients discontinued treatment, including two patients during induction and five patients during maintenance treatment. No grade 5 TRAE was reported. In the non-smoker participants, the mPFS was 14.5 (95% CI: 4.0–25.0) months.ConclusionsAnlotinib in combination with carboplatin/pemetrexed-based chemotherapy followed by anlotinib plus pemetrexed as maintenance therapy might be an effective choice in treating patients with wild-type EGFR/ALK advanced nsq-NSCLC.

Cabozantinib (C) plus atezolizumab (A) or C alone in patients (pts) with advanced non–small cell lung cancer (aNSCLC) previously treated with an immune checkpoint inhibitor (ICI): Results from Cohorts 7 and 20 of the COSMIC-021 study.

9005 Background: C, a multitargeted receptor tyrosine kinase inhibitor (TKI), promotes an immune-permissive environment that may enhance ICI activity. COSMIC-021 (NCT03170960) is a multicenter phase 1b study evaluating C + A in advanced solid tumors. In COSMIC-021, C + A demonstrated encouraging clinical activity in the cohort of pts with aNSCLC previously treated with ICIs (cohort 7 [C7]) (Neal. ASCO 2020. Abstr 9610). Updated outcomes of C + A in expanded C7 and outcomes for C alone in exploratory cohort 20 (C20) are presented. Methods: Pts with stage IV nonsquamous NSCLC without mutations in EGFR, ALK, ROS1, or BRAF V600E who progressed on one prior ICI and ≤2 prior lines of systemic anticancer therapy but no prior VEGFR TKI were eligible. Cohorts were not accrued contemporaneously. Pts received C 40 mg PO QD plus A 1200 mg IV Q3W (C7) or C alone 60 mg PO QD (C20). Primary endpoint was objective response rate (ORR) per RECIST v1.1 by investigator. Other endpoints included safety, duration of response (DOR), progression-free survival (PFS), and overall survival (OS). CT/MRI scans were performed Q6W for the first year and Q12W thereafter. Results: A total of 81 and 31 pts received C + A and C, respectively; baseline characteristics were as follows: median age, 67 y, 70 y; male, 57%, 58%; ECOG PS 1, 64%, 71%; liver metastasis, 21%, 23%; refractory to prior ICI (progressive disease [PD] as best response), 32%, 45%; median number of prior systemic therapies, 3 and 3. As of Nov 30, 2021, median follow-up (range) (mo) was 24.7 (10.7, 42.8) and 21.5 (17.3, 27.6) for C + A and C, respectively, with 6 (7%) and 1 (3%) on study treatment. Clinical activity was observed for C + A and C alone (Table). Most common treatment-related adverse events (TRAEs) of any grade for C + A and C, respectively, included diarrhea (40%, 42%), nausea (22%, 45%), decreased appetite (25%, 26%), vomiting (14%, 23%), and fatigue (28%, 19%); grade 3/4 TRAEs occurred in 44% and 52% and one grade 5 TRAE occurred in each cohort (pneumonitis [C + A] and gastric ulcer hemorrhage [C]). Conclusions: C + A and C demonstrated encouraging clinical activity with manageable toxicity in pts with aNSCLC previously treated with ICIs. A phase 3 trial (CONTACT-01; NCT04471428) of C + A vs docetaxel is ongoing in NSCLC previously treated with an ICI and platinum-containing chemotherapy. Clinical trial information: NCT03170960. [Table: see text]

Efficacy and safety of pembrolizumab in combination with anlotinib in the treatment of refractory or recurrent high-grade serous ovarian cancer: A phase 2 nonrandomized clinical trial.

5543 Background: Anlotinib, an oral multi-targeted receptor tyrosine kinase inhibitor (TKI), exhibits good safety and efficacy in many advanced refractory solid tumors. Previous studies have indicated that anlotinib has synergistic effects with anti–programmed death-1 antibodies via modulation of the tumor microenvironment. Our study aims to examine the efficacy and safety of anlotinib-pembrolizumab combination therapy as a treatment for refractory or recurrent High-Grade Serous Ovarian Cancer. Methods: Patients with refractory or recurrent High-Grade Serous Ovarian Cancer received pembrolizumab (200 mg, intravenously over 60 minutes, once every 3 weeks) plus anlotinib (12 mg/day, orally, 2 weeks on and 1 week off, every 3 weeks) therapy or pembrolizumab (200 mg, intravenously over 60 minutes, once every 3 weeks) monotherapy, respectively. Primary end points were progression-free survival (PFS) and overall survival (OS). The relationships of potential biomarkers with clinical efficacy were also evaluated. Results: A total of 33 patients were enrolled, with 15 participants received the anlotinib-pembrolizumab combination regime and 18 with pembrolizumab monotherapy, respectively. Grade 3 treatment-related adverse events (TRAEs) were recorded in 3 participants (20%) receive the combination treatment and 3 (16.7%) in the pembrolizumab monotherpay group, respectively. The PFS were 13.0 months and 8.0 months to anlotinib-pembrolizumab combination regime and pembrolizumab mono-treatment, respectively. And the OS of the two groups were equal as 31 months. In the anlotinib-pembrolizumab combination treatment group, patients with ARID1A mutation indicated a significantly survival benefit compared patient with the wide type (PFS: 12.5 VS. 7.0, P = 0.004 ). Conclusions: The anlotinib-pembrolizumab combination showed promising efficacy and favorable safety as treatment for refractory or recurrent High-Grade Serous Ovarian Cancer. The ARID1A are potential biomarkers for predicting the efficacy of this novel regimen.

Cabozantinib (C) in combination with atezolizumab (A) in urothelial carcinoma (UC): Results from Cohorts 3, 4, 5 of the COSMIC-021 study.

4504 Background: C, a multitargeted receptor tyrosine kinase inhibitor (TKI), promotes an immune-permissive environment that may enhance response to immune checkpoint inhibitors (ICIs). COSMIC-021, a multicenter phase 1b study, is evaluating C + A (anti‒PD-L1 therapy) in various solid tumors (NCT03170960). C + A demonstrated encouraging clinical activity in cohort 2 of COSMIC-021 in patients (pts) with UC previously treated with platinum-containing chemotherapy (chemo) (Pal S et al. ASCO 2020. Abstract 5013). Outcomes of C + A from 3 other UC cohorts (C3, C4, C5) are presented. Methods: Pts with inoperable locally advanced/metastatic UC with transitional cell histology and ECOG PS 0‒1 were eligible. Pts enrolled in C3 and C4 had no prior therapy and were cisplatin-based chemo ineligible (C3) or eligible (C4). C5 enrolled pts with one prior ICI and no prior VEGFR-TKI therapy. Pts received C 40 mg PO QD and A 1200 mg IV Q3W. CT/MRI scans were performed Q6W for first year and Q12W thereafter. The primary endpoint is objective response rate (ORR) per RECIST v1.1 by investigator. Other endpoints: safety, duration of response (DOR), PFS, and OS. Results: Thirty pts each were enrolled in C3 and C4, and 31 in C5. Baseline characteristics for C3, C4, and C5, respectively: median age, 74 y, 66 y, 68 y; male, 67%, 73%, 55%; ECOG PS 1, 63%, 57%, 74%; lung/liver metastasis; 33%/17%, 40%/20%, 58%/23%; ≥3 tumor sites, 30%, 43%, 45%; bladder as primary site, 67%, 70%, 71%. As of Nov 30, 2021, the median follow-up for C3, C4, and C5 was 27.9, 19.1, and 32.9 mo, respectively, with 1, 6, and 1 pts on treatment. C + A demonstrated clinical benefit across all cohorts (Table). Most common treatment-related adverse events (TRAEs) of any grade across C3, C4, and C5, respectively, were diarrhea (43%, 33%, 35%), nausea (27%, 17%, 26%), fatigue (27%, 27%, 48%), and decreased appetite (33%, 27%, 39%); grade 3/4 TRAEs occurred in 63%, 43%, and 45%, and there was no grade 5 TRAE. Conclusions: C + A demonstrated encouraging clinical activity with manageable toxicity in inoperable locally advanced/metastatic UC as first-line systemic therapy in cisplatin-based chemo eligible/ineligible pts and as second- or later line in pts who received prior ICI. Clinical trial information: NCT03170960. [Table: see text]