Targeted Kinase Inhibitors Research Articles

NFS-11. PHASE II STUDY OF AXITINIB IN PATIENTS WITH NEUROFIBROMATOSIS TYPE 2-RELATED SCHWANNOMATOSIS AND PROGRESSIVE VESTIBULAR SCHWANNOMAS

Abstract BACKGROUND Axitinib is an oral multi-receptor tyrosine kinase inhibitor targeting vascular endothelial growth factor receptor (VEGFR), platelet derived growth factor receptor (PDGFR), and c-KIT. These represent a clinically and/or preclinically validated molecular targets in vestibular schwannoma (VS). METHODS Eligible participants were age >5 years with a clinical diagnosis of neurofibromatosis type 2-related schwannomatosis (NF2-SWN) and at least one volumetrically measurable, progressive VS. Axitinib was given continuously in 28-day cycles for up to of 12 cycles. Primary endpoint was objective volumetric response rate to axitinib, hearing response was a secondary endpoint, along with validated quality of life assessments (NFTI-QOL). RESULTS Twelve participants were enrolled and eight completed 12 cycles, including two pediatric patients. Two patients were non-evaluable due to coming off study prior to the first scheduled response evaluation: one withdrew from the study for personal reasons and one for non-compliance. Due to slowing accrual, the study closed prior to meeting planned enrollment of 17 evaluable patients. Ten patients were evaluable for the primary endpoint, defined as ≥20% decrease in VS volume, with two volumetric responses observed; both were reached after three cycles and sustained during treatment. Best volumetric response was −53.9% after nine cycles. Hearing response was evaluable in nine participants, with three hearing responses observed, one of which was sustained during treatment. All participants experienced drug-related toxicities, the most common were diarrhea, hematuria and skin toxicity, not exceeding grade 2, as well as hypertension, not exceeding grade 3. NFTI-QOL scores remained stable or improved during treatment in all participants. CONCLUSIONS Axitinib therapy targeting VEGFR, PDGFR and c-KIT is feasible in this population and associated with volumetric and hearing responses in a subset of patients. The convenience of oral administration appears to be offset, however, by increased toxicity and lower response rates compared to VEGF-A targeted therapy with bevacizumab.

Epigenetic targets of Janus kinase inhibitors are linked to genetic risks of rheumatoid arthritis

BackgroundCurrent strategies that target cytokines (e.g., tumor necrosis factor (TNF)-α), or signaling molecules (e.g., Janus kinase (JAK)) have advanced the management for allergies and autoimmune diseases. Nevertheless, the molecular mechanism that underpins its clinical efficacy have largely remained elusive, especially in the local tissue environment. Here, we aimed to identify the genetic, epigenetic, and immunological targets of JAK inhibitors (JAKis), focusing on their effects on synovial fibroblasts (SFs), the major local effectors associated with destructive joint inflammation in rheumatoid arthritis (RA).MethodsSFs were activated by cytokines related to inflammation in RA, and were treated with three types of JAKis or a TNF-α inhibitor (TNFi). Dynamic changes in transcriptome and chromatin accessibility were profiled across samples to identify drug targets. Furthermore, the putative targets were validated using luciferase assays and clustered regularly interspaced short palindromic repeat (CRISPR)-based genome editing. ResultsWe found that both JAKis and the TNFi targeted the inflammatory module including IL6. Conversely, specific gene signatures that were preferentially inhibited by either of the drug classes were identified. Strikingly, RA risk enhancers for CD40 and TRAF1 were distinctively regulated by JAKis and the TNFi. We performed luciferase assays and CRISPR-based genome editing, and successfully fine-mapped the single causal variants in these loci, rs6074022-CD40 and rs7021049-TRAF1.ConclusionsJAKis and the TNFi had a direct impact on different RA risk enhancers, and we identified nucleotide-resolution targets for both drugs. Distinctive targets of clinically effective drugs could be useful for tailoring the application of these drugs and future design of more efficient treatment strategies.

Impact of molecular therapy on radioactive iodine uptake in patients with oncogene-driven metastatic differentiated thyroid cancer.

TPS10078 Background: Targetable kinase fusions and mutations are common in pediatric and young adult patients with papillary thyroid cancer (TC) and are associated with metastatic disease and lack of response to radioactive iodine therapy (RAI). While survival outcomes are excellent, less than 20% of children with metastatic TC achieve a complete response to standard treatment with surgery and radioactive iodine (RAI). Thus, repeated RAI therapy is common, increasing the risk of pulmonary fibrosis and secondary malignancies. Targeted kinase inhibitors are highly effective at shrinking oncogene-driven TC. Preliminary data suggest that these targeted therapies can improve tumor differentiation and RAI sensitivity. However, optimal integration of targeted therapy with standard of care RAI for TC remains uncertain. The objective of this study is to evaluate if targeted inhibitors in patients with metastatic, oncogene-driven differentiated TC will improve or restore tumor RAI uptake and ultimately induce durable clinical responses in patients with metastatic differentiated TC. Methods: Patients with TC lung metastases, both RAI naïve and refractory, with an identified targetable molecular driver (Table) and intent to start oncogene-specific targeted therapy are eligible for this study. Patients who received a prior oncogene-specific targeted therapy are excluded. A RAI-whole body scan (WBS) is performed at baseline and after 4 weeks of targeted therapy. Patients will be followed for up to 5 years to monitor clinical response. Response parameters include structural (CT, WBS, and/or neck US) and biochemical (thyroglobulin, thyroglobulin antibodies) evaluation. The primary endpoint is the change in RAI avidity between baseline and 4 weeks of treatment. This will be calculated as the ratio of RAI uptake in the lungs/disease sites versus the whole body for each subject at each time point. Secondary endpoints include progression free survival and the proportion of patients who achieve a complete response to the combination of targeted therapy and RAI. Five of 32 patients have been enrolled. Clinical trial information: NCT05024929 . [Table: see text]

Non-receipt of targeted and immunotherapies in diverse patients with metastatic cancers.

e13563 Background: The rapid evolution of molecularly targeted kinase inhibitors (TKIs) and immune checkpoint inhibitors (ICIs) in the treatment of metastatic cancer, coupled with high drug costs, raises potential for unwarranted variation in patient management. We evaluated correlates of non-receipt of TKIs and ICIs in a diverse, population-based sample of patients with metastatic non-small cell lung cancer (NSCLC), kidney and bladder (GU) cancer, and melanoma. Methods: We identified 2240 patients diagnosed in 2019 with metastatic NSCLC, GU cancer, or melanoma and reported to the Georgia or Los Angeles SEER registries. Using SEER registry data, we linked all patients to a managing oncology physician. We collected data from the managing physician regarding receipt of TKIs and ICIs. We used bivariate analyses and multivariable logistic regression models to assess associations between non-receipt of TKIs and ICIs and patient-level factors. Results: We present results for a preliminary sample (N=894). About half (55%) of the patients had NSCLC, 31% had GU cancer, and 14% had melanoma. The mean age was 62 (SD 12); 59% were male; 65% were White, 16% were Black, 11% were Hispanic, and 7% were Asian; 52% had Medicare, 29% had private insurance, 9% had Medicaid, and 4% had no insurance; 89% resided in urban areas, 11% resided in rural areas. 22% lived in a census tract area with ≥20% of the population living below the poverty level. The Table shows that in bivariate analyses, non-receipt of TKIs was associated with NSCLC, older age, male sex, non-white race, and non-private or no insurance (all p<0.05). After adjustment, non-receipt of TKIs was associated with NSCLC, older age, male sex, and race. Asian and Hispanic patients had lower rates of non-receipt, and Black patients had higher rates. In bivariate analyses, non-receipt of ICIs was associated with NSCLC and GU cancer (p=0.004); this association remained significant after adjustment. Conclusions: Non-receipt of TKIs was associated with important non-clinical factors including race and sex. Non-receipt of ICIs was associated only with cancer type. These findings suggest that policy-relevant factors such as out-of-pocket costs for oral cancer therapies and differential access to molecular sequencing may contribute to unwarranted variation in receipt of TKIs. [Table: see text]

Open-label, dose-escalation phase 1a study of SPH5030, a tyrosine kinase inhibitor (TKI) targeting HER2, in patients with HER2 positive advanced solid tumors.

Open-label, dose-escalation phase 1a study of SPH5030, a tyrosine kinase inhibitor (TKI) targeting HER2, in patients with HER2 positive advanced solid tumors.

Midline Low-Grade Gliomas of Early Childhood: Focus on Targeted Therapies.

Midline low-grade gliomas (mLGGs) of early childhood have a poorer prognosis compared with tumors of other localizations and in older patients. LGGs are associated with aberrant activation of RAS-RAF-MEK pathway, and pharmacological inhibition of the pathway has therapeutic promise. The aim of this study was clinical and molecular characterization of infantile mLGGs, with emphasis on the efficacy of targeted kinase inhibition. This study enrolled 40 patients with mLGG age <3 years. The majority of the patients (30/40) received first-line chemotherapy (CT) as per International Society of Paediatric Oncology LGG 2004 guidelines. In all patients, molecular genetic investigation of tumor tissue by polymerase chain reaction and RNA sequencing was performed. The median follow-up was 3.5 years. First-line CT failed in 24 of 30 recipients. The identified molecular profiles included KIAA1549::BRAF fusions in 26 patients, BRAF V600E in six patients, FGFR1::TACC1 fusions in two patients, and rare fusion transcripts in four patients. At disease progression, targeted therapy (TT) was initiated in 27 patients (22 patients received trametinib) on the basis of molecular findings. TT was administered for a median of 16 months, with partial response achieved in 12 of 26 (46%) patients in which response was evaluated. Severe adverse events were detected only on trametinib monotherapy: acute damage of GI or urinary mucosa complicated by hemorrhage and development of transfusion-dependent anemia in four patients and grade 3 skin toxicity in three patients. mLGGs of early childhood are often aggressive tumors, resistant to CT, and frequently require alternative treatment. The majority of patients harbor druggable molecular targets and respond to molecular TT.

A phase II trial of anlotinib combined chemotherapy as second-line and above therapy in HER2-negative advanced breast cancer.

e13140 Background: The group of HER2-negative accounts for about 75% of breast cancer and has limited response to chemotherapy. Anlotinib is a novel multitarget tyrosine kinase inhibitor targeting VEGFR, PDGFR, FGFR, and c-Kit. In this study, we assessed the efficacy and safety of anlotinib plus chemotherapy in second-line and above treatment of HER-2 negative advanced breast cancer. Methods: This open-label, single-arm, phase II study enrolled women aged 18-75 years with HER2-negative breast cancer who underwent at least one-line chemotherapy. All patients were treated with anlotinib (12mg, qd, administered orally on Days 1-14 of each 21 day cycle) in combination with investigator-selected chemotherapy. The primary endpoint evaluated in this study was the median progression-free survival (PFS). Secondary endpoints included the objective response rate (ORR), clinical benefit rate (CBR), disease control rate (DCR) and safety. Results: From August 2022 to August 2023, 33 patients were enrolled in this study including 22(66.7%) HR+/HER2- patients and 11(33.3%) TNBC patients. After a median follow-up time of 11 months (95% CI, 5.8-16.2), the median PFS (mPFS) of the all patients was 8.6 months (95% CI 7.3-NA). In the HR+ and HR- populations, mPFS was 7.6 months versus 9.5 months (HR,0.376 [95%CI 0.12-1.13], p=0.072), respectively. All the patients had the confirmed best overall response assessments, no patient achieved complete response (CR); 11(33.3%) patients got partial response (PR) and 19(57.6%) patients achieved stable disease (SD). ORR was 33.3% (95% CI 18.0-51.8), DCR was 90.9% (95% CI 75.7-98.1) and CBR was 60.6% (95% CI 42.1-77.1). The most frequently observed adverse events were elevated triglycerides (78.8%), elevated blood sugar (63.6%), anemia (60.6%), elevated cholesterol (51.5%), elevated alanine aminotransferase (48.5%), and leukopenia (48.5%). Dose reductions due to adverse events occurred in 7 (21.2%) patients. Conclusions: Anlotinib combined with chemotherapy showed a promising efficacy with an acceptable safety profile for second-line and above patients with HER2-negative metastatic breast cancer. Further studies enrolling more patients are still needed.

BGB-A317-212: A multicenter, open-label, phase II study to evaluate the efficacy and safety of tislelizumab in combination with lenvatinib in patients with selected solid tumors.

2610 Background: Tislelizumab, an anti-programmed cell death protein 1 (PD-1) monoclonal antibody, has demonstrated promising efficacy in several advanced solid tumors. However, some patients (pts) do not respond or develop resistance to tislelizumab monotherapy. Lenvatinib, a receptor tyrosine kinase inhibitor targeting VEGFR 1-3, FGFR 1-4, PDGFR alpha, KIT, and RET, has shown a potential synergistic effect with anti-PD-1 therapy. Here, we report the primary results of a phase II study evaluating the combination of tislelizumab plus lenvatinib in pts with solid tumors (NCT05014828). Methods: Pts with histologically/cytologically confirmed selected solid tumors, naïve to lenvatinib and anti-programmed death-ligand 1 (PD-L1)/PD-1 therapies were enrolled. Part 1 (safety run-in) determined the recommended phase II dose (RP2D) of lenvatinib in combination with tislelizumab 400 mg IV every 6 weeks. In Part 2 (expansion), pts received lenvatinib at the RP2D from Part 1 (20 mg orally/day) plus tislelizumab per the Part 1 regimen until disease progression, withdrawal, or death. The primary endpoints were safety and RP2D determination (Part 1) and overall response rate (ORR; Part 2). Results: At data cutoff (Oct 20, 2023; median follow-up 12.1 months [mo; renal cell carcinoma, RCC]; 10.8 mo [head and neck squamous cell carcinoma, HNSCC]; 14.8 mo [gastric cancer, GC], and 22.0 mo [non-small cell lung cancer, NSCLC]), 58 pts were treated in Part 2 (RCC, n=23; HNSCC, n=27; GC, n=3; NSCLC, n=5), 6 of whom were also included in Part 1. The ORR was 66.7% in pts with RCC, 33.3% (HNSCC), 33.3% (GC), and 20.0% (NSCLC). Median duration of response (mDoR) was 18.5 mo and 9.6 mo in pts with NSCLC and HNSCC, respectively; not estimable (NE) for RCC and GC (Table). No new safety signals were identified; grade ≥3 treatment-related adverse events were reported in 78.3%, 59.3%, 33.3% and 60.0%, of pts with RCC, HNSCC, GC, and NSCLC, respectively (Table). Conclusions: Tislelizumab plus lenvatinib had a manageable safety profile and showed preliminary antitumor activity in pts with selected tumor types. Longer follow-up is needed to further investigate the potential of this combination to benefit pts with advanced solid tumors. Clinical trial information: NCT05014828 .[Table: see text]

Pyrotinib in HER2-altered advanced salivary gland carcinomas: Analysis of two cohorts from an exploratory study.

6108 Background: The HER2 altered in a subset of salivary gland cancers (SGCs). Pyrotinib is an oral irreversible pan-HER receptor tyrosine kinase inhibitor targeting HER1, HER2, and HER4. In this study, we assessed the efficacy and safety of pyrotinib in patients with HER2-amplified/overexpressed/mutated advanced SGCs, including recurrent/metastatic(R/M) and locally advanced (LA) patients with high-risk of recurrence. Methods: R/M and high-risk LA SGCs with HER2-alteration were enrolled. Pyrotinib (400 mg) was given orally once daily. In LA cohort, pyrotinib were given as adjuvant therapy after standard surgery and postoperative radiation. Results: Between August 2019 and August 2023, 18 patients were enrolled (10 in R/M cohort and 8 in LA cohort). In R/M cohort, the median age was 58.5 years, and all patients were grade III. The ORR was 90%, including 2 CRs, 7 PRs and 1PD; median DOR was 5.7 months (range: 3.1-13.7) and median PFS was 7.6 months (range: 2.7-16.8). In LA cohort, the median age was 59.0 years, and all patients but one were grade III. All patients but one had T4 disease; 5 patients had N3 and 2 had N2b disease; 5 patients had ENE and 5 patients had positive margin. With a median follow up 21.3 months, only 3 patients experienced recurrence, and one patient died due to non-tumor reasons. The estimated 2-years PFS and 2-years OS were 75% and 100%. The most common adverse event was diarrhea, which occurred in 11/18 (61.1%) patients and 3/18 (16.7%) were grade III. Conclusions: Pyrotinib showed promising antitumor activity in recurrent/metastatic HER2-altered SGCs, and had a potential to prolong survival outcome as adjuvant treatment in LA patients setting, which needs further randomized studies. Clinical trial information: NCT05087706 .

Efficacy and safety of surufatinib, toripalimab, nab-paclitaxel in combination with radiotherapy or surgery in the first-line treatment of esophageal squamous cell cancer: A single-centered prospective clinical trial.

e16047 Background: Chemotherapy(CT) plus immune checkpoint inhibitors (ICIs) has become the current standard of care in the first-line treatment of metastatic esophageal squamous cell cancer(ESCC). In locally advanced setting, radiochemotherapy with or without resection remains the standard of care. Surufatinib, a novel small-molecule kinase inhibitor targeting VEGFR1-3, FGFR and CSF-1R, in combination with PD-1 inhibitors have demonstrated synergistic anti-tumor activities in previous studies. This single-centered prospective clinical trial aims to evaluate the efficacy and safety of surufatinib(SUR), toripalimab(TOR), nab-paclitaxel(NAB) in combination with radiotherapy or surgery in the first-line treatment of locally advanced(LA) or metastatic(R/M) ESCC. Methods: Eligible patients(pts) with confirmed LA or R/M, ECOG PS 0-2 and no prior systematic treatment were enrolled in the trial. Pts would receive 260mg/m2 NAB and TOR 240mg on day 1 and SUR 250mg once daily in each 21-day cycle as induction therapy for two cycles, followed by surgery or another two cycles of concurrent chemoradiotherapy(CCRT) with NAB, SUR and radiotherapy, in which involved-field irradiation were conducted at the dose of 50-63 Gy/25-30F, 1.8-2 Gy per fraction, 5 fractions per week. As maintenance therapy, daily SUR and TOR every three week were administered until disease progression or unacceptable toxicities. Progression-free survival (PFS) was the primary endpoint. Results: As of Jan 7, 2024, 16 pts were enrolled, of whom 15 were evaluable. 14(87.5%) pts were male. The median age was 69.5 (range: 45-79). Tumor located in upper(18.8%), middle(25%) and lower(56.2%) thoracic. 1(6.2%) is Stage II disease, 12(75%) Stage III and 3(18.8%) Stage IV. 8 (50%) pts were with PD-L1 CPS greater than 1, 5 (31.25%) pts greater than 5, and 3 (18.75%) pts greater than 10. PD-L1 CPS of 6(37.50%) pts was unknown. With a median follow-up time of 5 (range: 1-12) months, despite the immatureness of PFS, the 12-month PFS rate was 77.14% (95% CI: 48.89%-100%). The objective response rate was 93.3% (14/15), and disease control rate was 100% (15/15). Five of the included pts met the resection criteria during treatment and underwent subsequent R0 resection. The most common adverse events (≥20%) of all grades were hypoesthesia (62.5%), nausea and vomiting (50%), and white blood cell decrease (43.75%). Conclusions: The combination ofsurufatinib, toripalimab, nab-paclitaxel with radiotherapy or surgery has demonstrated promising efficacy and a well-tolerated safety profile as a potential first-line treatment for LA or R/M ESCC. This ongoing trial merits further investigation and holds significant implications for clinical practice.

In vitro inhibitory effects of selumetinib on activity of human UDP-glucuronosyltransferases and prediction of in vivo drug-drug interactions

Selumetinib is an oral, effective, and selective tyrosine kinase inhibitor targeting mitogen-activated protein kinase 1 and 2 (MEK1/2), which is clinically active in multiple tumor types, such as neurofibromatosis type 1 (NF1), melanoma, gliomas and non-small cell lung cancer (NSCLC). The purpose of this article was to assess the effects of selumetinib on the activities of twelve human UDP-glucosyltransferases (UGTs) including UGT1A1, 1A3, 1A4, 1A6, 1A7, 1A8, 1A9, 1A10, 2B4, 2B7, 2B15, and 2B17, and its potential for inducing clinical drug-drug interactions (DDIs). The results demonstrated that selumetinib potently inhibited the activity of UGT2B7 through the mechanism of mixed inhibition with the inhibition constant value of 5.79 ± 0.65 μM. Furthermore, the plasma concentration of UGT2B7 substrate as the co-administered drug was predicted to be increased by at least 84 % when patients took selumetinib 75 mg twice daily, suggesting a high potential to induce clinical DDIs. Selumetinib exhibited weak inhibitory effects on other human UGTs and was unlikely to trigger off UGTs-mediated DDIs except for UGT2B7. Therefore, the combination of selumetinib with the substrate drug of UGT2B7 requires additional attention to avoid adverse events in clinical treatment.

Emerging therapeutic options for follicular-derived thyroid cancer in the era of immunotherapy.

Although most follicular-derived thyroid cancers are well differentiated and have an overall excellent prognosis following treatment with surgery and radioiodine, management of advanced thyroid cancers, including iodine refractory disease and poorly differentiated/undifferentiated subtypes, is more challenging. Over the past decade, better understanding of the genetic drivers and immune milieu of advanced thyroid cancers has led to significant progress in the management of these patients. Numerous targeted kinase inhibitors are now approved by the U.S Food and Drug administration (FDA) for the treatment of advanced, radioiodine refractory differentiated thyroid cancers (DTC) as well as anaplastic thyroid cancer (ATC). Immunotherapy has also been thoroughly studied and has shown promise in selected cases. In this review, we summarize the progress in the understanding of the genetic landscape and the cellular and molecular basis of radioiodine refractory-DTC and ATC, as well as discuss the current treatment options and future therapeutic avenues.

Abstract PO2-08-05: ERBB2 mutated breast cancer detected by next generation sequencing: integrated analysis based on real-world data and The Cancer Genome Atlas

Abstract Background ERBB2 mutation has been recognized as an actionable target for pan-HER tyrosine kinase inhibitors in the era of precision medicine for solid tumors. In our real-world cohort utilizing next-generation sequencing (NGS), we successfully identified cases of ERBB2-mutated breast cancer. Furthermore, we investigated the clinical and pathological characteristics of these cases by integrating our data with The Cancer Genome Atlas (TCGA). Methods Our real-world cohort with NGS included 423 breast cancer patients treated at Gangnam Severance Hospital in Seoul, Republic of Korea, between April 2017 and January 2023. Among these patients, 13 were confirmed to have ERBB2 mutation through NGS analysis. We also incorporated data from TCGA database, which included 818 cases with ERBB2 sequencing. We compared the clinical characteristics (age, sex, stage, and ER, PR, and HER2 status) between the two groups. Furthermore, we examined the frequency of two of the most common mutations, PIK3CA and TP53, in both groups. Additionally, we investigated the distribution of PAM50 subtypes in the TCGA cohort. Results This study analyzed a total of 1,244 cases with NGS data. Among these cases, 31 (2.5%) exhibited ERBB2 mutation, with 13 patients identified in our dataset and 18 in the TCGA data. Among the 31 cases with ERBB2 mutation, 21 (67.7%) had HER2-negative disease. No significant differences were observed in other clinical characteristics based on ERBB2 status. Within the group of 31 ERBB2-mutated cases, TP53 mutations were found in 12 cases (38.7%), while PIK3CA mutations were found in 12 cases (38.7%). In the TCGA dataset, 4 cases (22.2%) with ERBB2 mutation were classified as HER2-E subtype, and the rate of HER2-E subtype was significantly higher in the ERBB2-mutated group compared to the ERBB2-wild group (22.2% vs. 7.6%, p=0.024). Conversely, 14 cases (77.8%) with ERBB2 mutation exhibited a non-HER2 enriched subtype. Conclusions Consistent with previous knowledge, ERBB2 mutations can be detected in HER2-negative breast cancer, despite their rarity. Furthermore, a considerable proportion of ERBB2-mutated breast cancer may depend on various oncogenic signaling pathways other than the HER2 pathway. Further studies are warranted to optimize therapeutic strategies for ERBB2-mutated breast cancer. Citation Format: Junghyun Kim, Yoonwon Kook, Seung Ho Baek, Min Ji Kim, Sohyun Moon, Seung Eun Lee, Jee Hung Kim, Soong June Bae, Joon Jeong, Sung Gwe Ahn. ERBB2 mutated breast cancer detected by next generation sequencing: integrated analysis based on real-world data and The Cancer Genome Atlas [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 PO2-08-05.

Characterizing heterogeneous single-cell dose responses computationally and experimentally using threshold inhibition surfaces and dose-titration assays

Single cancer cells within a tumor exhibit variable levels of resistance to drugs, ultimately leading to treatment failures. While tumor heterogeneity is recognized as a major obstacle to cancer therapy, standard dose-response measurements for the potency of targeted kinase inhibitors aggregate populations of cells, obscuring intercellular variations in responses. In this work, we develop an analytical and experimental framework to quantify and model dose responses of individual cancer cells to drugs. We first explore the connection between population and single-cell dose responses using a computational model, revealing that multiple heterogeneous populations can yield nearly identical population dose responses. We demonstrate that a single-cell analysis method, which we term a threshold inhibition surface, can differentiate among these populations. To demonstrate the applicability of this method, we develop a dose-titration assay to measure dose responses in single cells. We apply this assay to breast cancer cells responding to phosphatidylinositol-3-kinase inhibition (PI3Ki), using clinically relevant PI3Kis on breast cancer cell lines expressing fluorescent biosensors for kinase activity. We demonstrate that MCF-7 breast cancer cells exhibit heterogeneous dose responses with some cells requiring over ten-fold higher concentrations than the population average to achieve inhibition. Our work reimagines dose-response relationships for cancer drugs in an emerging paradigm of single-cell tumor heterogeneity.

Population pharmacokinetic-pharmacodynamic modeling of serum biomarkers as predictors of tumor dynamics following lenvatinib treatment in patients with radioiodine-refractory differentiated thyroid cancer (RR-DTC).

Lenvatinib is a receptor tyrosine kinase (RTK) inhibitor targeting vascular endothelial growth factor (VEGF) receptors 1-3, fibroblast growth factor (FGF) receptors 1-4, platelet-derived growth factor receptor-α (PDGFRα), KIT, and RET that have been implicated in pathogenic angiogenesis, tumor growth, and cancer. The primary objective of this work was to evaluate, by establishing quantitative relationships, whether lenvatinib exposure and longitudinal serum biomarker data (VEGF, Ang-2, Tie-2, and FGF-23) are predictors for change in longitudinal tumor size which was assessed based on data from 558 patients with radioiodine-refractory differentiated thyroid cancer (RR-DTC) receiving either lenvatinib or placebo treatment. Lenvatinib PK was best described by a 3-compartment model with simultaneous first- and zero-order absorption and linear elimination from the central compartment with significant covariates (body weight, albumin <30 g/dL, ALP>ULN, RR-DTC, RCC, HCC subjects, and concomitant CYP3A inhibitors). Except for body weight, none of the covariates have any clinically meaningful effect on exposure to lenvatinib. Longitudinal biomarker measurements over time were reasonably well defined by a PK/PD model with common EC50, Emax, and a slope for disease progression for all biomarkers. Longitudinal tumor measurements over time were reasonably well defined by a tumor growth inhibition Emax model, which in addition to lenvatinib exposure, included model-predicted relative changes from baseline over time for Tie-2 and Ang-2 as having significant association with tumor response. The developed PK/PD models pave the way for dose optimization and potential prediction of clinical response.

Microsatellite instability: A 2024 update.

Deficient mismatch repair (dMMR) results in microsatellite instability (MSI), a pronounced mutator phenotype. High-frequency MSI (MSI-H)/dMMR is gaining increasing interest as a biomarker for advanced cancer patients to determine their eligibility for immune checkpoint inhibitors (ICIs). Various methods based on next-generation sequencing (NGS) have been developed to assess the MSI status. Comprehensive genomic profiling (CGP) testing can precisely ascertain the MSI status as well as genomic alterations in a single NGS test. The MSI status can be also ascertained through the liquid biopsy-based CGP assays. MSI-H has thus been identified in various classes of tumors, resulting in a greater adoption of immunotherapy, which is hypothesized to be effective against malignancies that possess a substantial number of mutations and/or neoantigens. NGS-based studies have also characterized MSI-driven carcinogenesis, including significant rates of fusion kinases in colorectal cancers (CRCs) with MSI-H that are targets for therapeutic kinase inhibitors, particularly in MLH1-methylated CRCs with wild-type KRAS/BRAF. NTRK fusion is linked to the colorectal serrated neoplasia pathway. Recent advances in investigations of MSI-H malignancies have resulted in the development of novel diagnostic or therapeutic techniques, such as a synthetic lethal therapy that targets the Werner gene. DNA sensing in cancer cells is required for antitumor immunity induced by dMMR, opening up novel avenues and biomarkers for immunotherapy. Therefore, clinical relevance exists for analyses of MSI and MSI-H-associated genomic alterations in malignancy. In this article, we provide an update on MSI-driven carcinogenesis, with an emphasis on unique landscapes of diagnostic and immunotherapeutic strategies.

Targeting metabolic adaptive responses induced by glucose starvation inhibits cell proliferation and enhances cell death in osimertinib-resistant non-small cell lung cancer (NSCLC) cell lines

Osimertinib, a tyrosine kinase inhibitor targeting mutant EGFR, has received approval for initial treatment in patients with Non-Small Cell Lung Cancer (NSCLC). While effective in both first- and second-line treatments, patients eventually develop acquired resistance. Metabolic reprogramming represents a strategy through which cancer cells may resist and adapt to the selective pressure exerted by the drug. In the current study, we investigated the metabolic adaptations associated with osimertinib-resistance in NSCLC cells under low glucose culture conditions. We demonstrated that, unlike osimertinib-sensitive cells, osimertinib-resistant cells were able to survive under low glucose conditions by increasing the rate of glucose and glutamine uptake and by shifting towards mitochondrial metabolism. Inhibiting glucose/pyruvate contribution to mitochondrial respiration, glutamine deamination to glutamate, and oxidative phosphorylation decreased the proliferation and survival abilities of osimertinib-resistant cells to glucose starvation. Our findings underscore the remarkable adaptability of osimertinib-resistant NSCLC cells in a low glucose environment and highlight the pivotal role of mitochondrial metabolism in mediating this adaptation. Targeting the metabolic adaptive responses triggered by glucose shortage emerges as a promising strategy, effectively inhibiting cell proliferation and promoting cell death in osimertinib-resistant cells.

Abstract 1829: Brusatol overcomes tyrosine kinase inhibitors resistance in myeloid leukemia cells by inhibiting translation of fast turnover protein cyclin D1 and Mcl-1

Abstract Myeloid leukemia is characterized with fast proliferation and apoptosis evasion, which are controlled by mutant or activated tyrosine kinase signalings. Tyrosine kinase inhibitors (TKI) targeting BCR-ABL in chronic myeloid leukemia (CML) and FLT3-ITD in acute myeloid leukemia (AML) significantly improved the therapy, but not cure, due to the general resistance. Overactivated mTOR protein translation pathway is believed to be one of the mechanisms causing resistance and that targeting protein translation should be one effective approach to overcome resistance. Brusatol is a quassinoid extracted from the fruit of Brucea javanica and an inhibitor of protein translation. We tested its antiproliferation and apoptosis induction in a variety of AML and CML cell lines as well as in TKI resistant cell lines. Brusatol effectively inhibits the growth of seven leukemia cell lines with GI50 values less than 20 nM. Brusatol induces apoptosis in AML cell lines and induces G0/G1 phase arrest in CML cell lines. Brusatol decreases the levels of fast turnover protein cyclin D1 and Mcl-1. In FLT3-ITD inhibitor sorafenib resistant MOLM-13/Sor cell line brusatol exhibits similar growth inhibition and apoptosis induction with the parental MOLM-13 cells, associated with inhibition of Mcl-1 and FLT3-ITD proteins. In BCR-ABL inhibitor imatinib resistant K562/STI cell line brusatol is effective as in parental K562 cells, associated with inhibition of cyclin D1 and BCR-ABL proteins. Brusatol at 2 mg/kg effectively inhibit tumor growth of K562 xenografts without causing toxicity to normal organs. These data indicate that brusatol inhibits oncogenic protein translation and has potential to be used to treat TKI resistant leukemia. Citation Format: Huiming Hua, Ying Yang, Guangfuxin Lin, Jingyi Zhang, Samuel Waxman, Yongkui Jing. Brusatol overcomes tyrosine kinase inhibitors resistance in myeloid leukemia cells by inhibiting translation of fast turnover protein cyclin D1 and Mcl-1 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1829.

Abstract 514: Salt-inducible kinase inhibitor OMX-0407 drives cell-cycle arrest in vitro and in vivo: An in-depth MoA analysis by phospho-proteomics

Abstract Based on iOmx’ proprietary iOTargTM genetic screening platform, salt-inducible kinase (SIK) 3 was identified as a novel cell signaling modulator in cancer biology. OMX-0407, an orally available, spectrum-selective kinase inhibitor targets several members of the SIK family and is known to prevent tumor-promoting function of the SIK-family through repolarization of the tumor microenvironment by enhancing caspase-mediated apoptosis upon death-receptor signaling. In addition, OMX-0407 inhibits individual key members of the tyrosine and tyrosine-like kinase family that are involved in cancer cell proliferation and cell cycle regulation. Via this dual mode of action, OMX-0407 has the potential to effectively fight solid tumors as exemplified by its striking single-agent efficacy in multiple pre-clinical tumor models. A comprehensive anti-tumor viability screen of &amp;gt;200 human cancer cell lines revealed striking effects of OMX-0407 on cancer cell viability across various cancer indications, resulting in a distinct sensitivity profile across various tumor indications with particularly strong effects on renal cell carcinoma (RCC) and squamous non-small cell lung cancer (sqNSCLC). Phospho-proteomics screening demonstrated pharmacodynamic activity of OMX-0407 in sensitive tumor cell lines via inhibition of key cellular processes such as cell motility, proliferation, and cell cycle regulation across different indications. Orthogonal functional in vitro assays confirmed the association of the OMX-0407-mediated anti-tumor efficacy with the arrest of G1/S transition and corresponding downregulation of cell cycle associated proteins PAK1/2 and ARHGAP35. The profound impact of OMX-0407 on fundamental regulatory mechanisms of cell division and cancer cell apoptosis translates into dose-dependent single-agent, anti-tumor efficacy in various pre-clinical tumor models of selected indications. Combination with Axitinib, a selective orally available inhibitor of vascular endothelial growth factor receptor 2, significantly enhanced anti-tumor efficacy and pharmacodynamic inhibition of cell growth as well as angiogenesis. These data further strengthen the potential of OMX-0407 in the treatment of RCC as well as other indications. In summary, OMX-0407 is a novel spectrum selective kinase inhibitor, currently under evaluation in a clinical Phase I trial (NCT05826600). OMX-0407 demonstrates strong anti-tumor efficacy in monotherapy in selected sensitive indications through a dual-pronged MoA, by modulating the tumor microenvironment and exerting direct anti-tumor activity in solid tumor indications with high unmet medical need. Citation Format: Ilona-Petra Maser, Marisa Stebegg-Wagner, Bettina Bauer, Filippos Konstantinidis, Andreas Schirmer, Moritz Zulley, Sonja Lacher, Barbara Kracher, Parastou Kohvaei, Murray Yule, Hannes Loferer, Stefan Bissinger. Salt-inducible kinase inhibitor OMX-0407 drives cell-cycle arrest in vitro and in vivo: An in-depth MoA analysis by phospho-proteomics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 514.

Abstract 6257: Genome wide, high-throughput, high-resolution structural variation detection at low variant allele fraction for oncology samples

Abstract Structural variation detection remains an elusive undertaking. For decades, G-banded karyotyping has remained the standard practice for nearly all hematological malignancy samples. Cancers are diseases of the genome and structural variants (SVs) are a hallmark of nearly all cancers, are often drivers of oncogenicity, and can sometimes be targeted for treatment, as highlighted by the discovery of the Philadelphia chromosome and later the development of targeted kinase inhibitors. One of the most important limitations of karyotyping, its requirement for cells to divide in culture, has prevented its application for most solid tumors and therefore, there is considerably less understanding of the impact of SVs in solid tumors. Optical genome mapping is a technique that is revolutionizing cytogenomics and unlocking the understanding of SVs in the genome at a level never seen before. It not only can detect nearly all variants that a karyotype can, but it can provide 10,000x higher resolution and does not require cell culture. Because of this, it is being adopted for oncology studies across hematological malignancies and solid tumors. This study demonstrates the performance of a new high throughput Stratys instrument for generation of optical genome map data at extraordinarily high coverage depth. With this instrument, 12 samples can be loaded at once, each loaded onto its own cartridge and the instrument can collect 400x genome coverage for each of these samples in 24 hours. The instrument has random access to the cartridges so that completed samples can be swapped out to facilitate optimal instrument run efficiency. To date, this system has been demonstrated to run 60 samples in a week, each at 400x coverage. Data from the instrument can be processed by Bionano Access™ and VIA™ software to call SVs, copy number variants (CNVs), regions of loss of heterozygosity (LOH), on a genome wide basis, and to classify those variants automatically according to guidelines such as the National Comprehensive Cancer Network (NCCN), World Health Organization (WHO), and National Health Services (NHS, United Kingdom). This new high throughput system with advanced bioinformatic data analysis has the potential to further transform structural variation analysis in cancer research. Citation Format: Alex R. Hastie, Pat Lynch. Genome wide, high-throughput, high-resolution structural variation detection at low variant allele fraction for oncology samples [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6257.