Small Molecule Tyrosine Kinase Inhibitors Research Articles

HER2CLIMB-04: Phase 2 open label trial of tucatinib plus trastuzumab deruxtecan in patients with HER2+ unresectable locally advanced or metastatic breast cancer with and without brain metastases (trial in progress).

TPS1097 Background: Tucatinib (TUC) is an oral, reversible, small molecule tyrosine kinase inhibitor highly selective for human epidermal growth factor receptor 2 (HER2) with minimal inhibition of human epidermal growth factor receptor (EGFR). In the pivotal, randomized HER2CLIMB trial (NCT02614794), the combination of TUC + trastuzumab (T) + capecitabine (C) demonstrated statistically significant and clinically meaningful improvements in progression free survival (PFS), overall survival (OS), and PFS in patients (pts) with brain metastases (BM), compared to T + C alone. These data supported regulatory approvals in the US and internationally for TUC in combination with T + C in pts with HER2+ metastatic breast cancer (MBC). Trastuzumab deruxtecan (T-DXd) is an antibody-drug conjugate of trastuzumab and a topoisomerase I inhibitor payload approved in the US for treatment of HER2+ MBC in pts who have received 2 or more prior anti-HER2 regimens in the metastatic setting. Approval was based on data from the single arm Destiny-Breast01 trial (NCT03248492) where treatment with T-DXd resulted in a confirmed objective response rate (cORR) of 61.4% (95% CI: 54.0, 68.5) in pts with HER2+ MBC who had prior ado-trastuzumab emtansine treatment. Despite these advances, HER2+ MBC remains incurable, and pts will eventually progress on currently available therapies. Combining TUC and T-DXd may result in further improvement on the efficacy seen with either agent alone. Methods: HER2CLIMB-04 (NCT04539938) is a single arm, open-label phase 2 trial evaluating safety and antitumor activity of TUC + T-DXd in pts with HER2+ unresectable locally-advanced or MBC who have received 2 or more prior HER2-based regimens in the metastatic setting. Pts with BM, including active BM, may be enrolled. Ten pts will be enrolled in the safety lead-in portion of the trial and followed for at least 1 cycle. If safety of the combination is acceptable, the trial will continue until approximately 60 response-evaluable pts have been enrolled, approximately evenly distributed between pts with and without BM. The primary endpoint is cORR by investigator (INV) per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1. Secondary endpoints are PFS, duration of response (DOR), and disease control rate (DCR) by INV per RECIST v1.1, OS, and safety. Exploratory endpoints will include cORR, PFS, DOR, DCR by independent central review per RECIST v1.1, pharmacokinetic analyses, biomarker analyses, and changes in patient-reported outcomes using the European Quality of Life 5-Dimension 5-Level instrument. Enrollment began in late 2020 in the United States. Clinical trial information: NCT04539938 .

A phase III study (APROMISS) of AL3818 (Catequentinib, Anlotinib) hydrochloride monotherapy in subjects with metastatic or advanced synovial sarcoma.

11505 Background: AL3818 (Catequentinib, Anlotinib) is a novel, orally administered, small molecule tyrosine kinase inhibitor. The primary objective of this Phase 3 study is to evaluate the efficacy of AL3818 monotherapy in patients (pts) with synovial sarcoma (SS) comparing with dacarbazine in randomization setting. Methods: Patients with a diagnosis of synovial sarcoma requiring second line or further line treatment were eligible for enrollment. The regimen was a 21-day cycle with oral AL3818 administered on 14 days on and 7 days off. This phase 3 trial is randomized in 2:1 ratio of AL3818 comparing to dacarbazine with option of crossover after PD of dacarbazine treatment. Progression free survival (PFS) with Log Rank test is the primary endpoint and this trial for SS is currently completed enrolled in US and Italy. Results: Total 79 pts initiated treatment and are evaluable, 52 received AL3818 as treatment arm (T), and 27 received dacarbazine (D) as control arm (C). Arms T/C median ages were 40.5/42.0 years (range: 18-70+) and 20/16 (38.5%/59.3%) were male. Overall, PFS was 2.89 months (95% CI: 2.73 – 6.87) for AL3818 and 1.64 (95% CI: 1.45 – 2.70) for D. The PFS of study met the primary endpoint with a p-value of 0.0015 and a HR of 0.449 (95% CI: 0.270– 0.744). At the month 4, 6, and 12, the percentages of progression free patients for AL3818 were 48.1%, 42.3% and 26.9%; and for D were 14.85%, 11.1% and 3.7%. For grade 3 treatment-related adverse events, 12(23.1%) of pts experienced for AL3818 and 7(25.9%) of pts experienced for D. The most common AL3818 related grade 3 AEs were diarrhea (5.8%) and hypertension (3.8%). Conclusions: This phase III trial demonstrates improved disease control and superior progression free survival for AL3818 vs dacarbazine in advanced SS. In addition, the study further confirms the acceptable benefit-risk profile of AL3818 from the prior randomized Phase 2b soft tissue sarcoma study (NCT02449343). AL3818 is a meaningful treatment option for pts with advanced SS. Clinical trial information: NCT 03016819 Clinical trial information: NCT03016819.

Apatinib plus vinorelbine versus vinorelbine for advanced triple-negative breast cancer with failed first or second-line treatment: The NAN trial.

1075 Background: No standard treatment exists for triple negative breast cancer (TNBC) with failure of multi-line therapies. Apatinib is a small-molecule tyrosine kinase inhibitor that has promising anti-angiogenesis and antitumor activity for TNBC. We aimed to evaluate the safety and efficacy of adding apatinib to chemotherapy in patients with metastatic TNBC with failed first/second-line treatment. Methods: This randomized, open-label, phase 2 trial recruited patients with advanced TNBC who failed to receive first or second-line treatment. A total of 66 patients were randomly assigned, in a 1:1 ratio, to receive vinorelbine 25 mg/m2 (days 1, 8, 15) or vinorelbine 20 mg/m2 (days 7, 14, 21) with apatinib (250 mg once daily, days 1-5, 8-12, 15-19, if tolerable, the second cycle started with 500 mg per day) in 28-day cycles. The efficacy was evaluated every two treatment cycles (8 weeks ± 3 days). According to the RECIST criterion, patients with CR, PR and SD continued treatment until disease progression or unacceptable toxicity or withdrawal of consent. The primary end point was progression-free survival (PFS). Secondary end points included overall survival (OS), overall response rate (ORR) and safety. Results: Between Sep 14, 2017 and Dec 08, 2020, 66 patients underwent randomization. Median follow-up was 21.3 months. 33 received apatinib plus vinorelbine and 32 received vinorelbine (1 was withdrawal of consent). Median PFS was significantly longer in the apatinib plus vinorelbine group than in the vinorelbine group (3.8 months vs. 1.9 months; hazard ratio for disease progression or death, 1.76; 95% confidence interval [CI], 1.02 to 3.05; P= 0.039). Median OS was 14.6 months with apatinib plus vinorelbine and 14.1 months with vinorelbine (HR,1.34; 95% CI, 0.60 to 3.00; P= 0.469). The ORR was 48.5% in the apatinib plus vinorelbine group and 31.3% in the vinorelbine group ( P= 0.156). The most common treatment-related hematologic grade 3–4 adverse events in those treated with apatinib plus vinorelbine versus vinorelbine, respectively, were leukopenia (42.4% vs. 34.4%), granulocytopenia (57.6% vs. 28.1%), anemia (9.1% vs. 12.5%) and thrombocytopenia (3.1% vs. 3.0%). The most frequent grade 3 nonhematologic toxicities were hand–foot syndrome (21%), proteinuria (9%), hypertension (9%) and increased ALT (9%) and which only occurred in apatinib plus vinorelbine group. No treatment-related nonhematologic grade 4 adverse events or treatment-related deaths were observed. Conclusions: Collectively, among patients with advanced TNBC with failed first/second-line treatment, apatinib plus vinorelbine show a promising benefit in PFS compared to vinorelbine monotherapy. Apatinib plus vinorelbine regimen shows promising efficacy and manageable toxicity, which might be a previously unappreciated therapeutic option for advanced TNBC. Clinical trial information: NCT03254654 .

Apatinib plus paclitaxel versus placebo plus paclitaxel as second-line therapy in patients with gastric cancer with peritoneal carcinomatosis: A double-blind, randomized phase II trial.

e16022 Background: Individuals with gastric cancer who present with peritoneal metastasis (PM) have poor prognosis. VEGF and VEGFR-2-mediated angiogenesis can increase vascular permeability, mesothelial cell permeability and promote peritoneal metastasis and ascites formation. This study assessed whether apatinib, a small-molecule VEGFR-2 tyrosine kinase inhibitor, in combination with paclitaxel would improve survival in patients with gastric cancer with PM as second-line therapy. Methods: This was a randomized, placebo-controlled, double-blind phase 2 trial. Recruitment of the trial was stopped after 44 patients due to poor accrual. Patients aged 18 years or older with gastric adenocarcinoma with PM and disease progression after first-line chemotherapy (platinum plus fluoropyrimidine) were randomly assigned in a 1:1 ratio to receive apatinib or placebo 500 mg oral once daily plus paclitaxel 80 mg/m2 intravenously on days 1, 8, and 15 of a 28-day cycle. The primary endpoint was progression-free survival (PFS). Secondary endpoints included overall survival (OS), overall response rate (ORR), disease control rate (DCR) and safety profiles. Results: Between January 2017 and January 2019, 44 patients were randomly assigned to treatment (21 in Paclitaxel/apatinib group while 23 in Paclitaxel/placebo group). Median PFS was significantly longer in apatinib plus paclitaxel group than in placebo plus paclitaxel group (4.67 months [95% CI, 3.90 to 9.13 months] vs 4.07 months [95% CI, 1.93 to 5.00 months]; hazard ratio 0.46 [95% CI, 0.22 to 0.97]; P=0.037). There was no significant difference between the two groups in median OS (8.57 months vs. 9.03 months; P=0.85), ORR (19.0% vs. 4.3%; P=0.290) and DCR (76.2% vs. 52.2%, P=0.098). Apatinib group showed a higher incidence of proteinuria (38.1% vs. 4.3%; P=0.016), while no significant difference was found in the incidence of grade 3 or higher drug-related adverse events. Conclusions: Compared with placebo plus paclitaxel, the combination of apatinib with paclitaxel as second-line therapy significantly improved median PFS with an acceptable safety profile in patients with gastric cancer with peritoneal metastasis. Clinical trial information: NCT03144843. [Table: see text]

Efficacy and Safety of Apatinib Treatment for Advanced Cholangiocarcinoma After Failed Gemcitabine-Based Chemotherapy: An Open-Label Phase II Prospective Study.

PurposeAs a novel small-molecule vascular endothelial growth factor receptor-2 tyrosine kinase inhibitor (VEGFR2-TKI), Methylsulfonic apatinib (apatinib) exhibits a specific antitumor effect in various solid tumors via inhibition of angiogenesis. The present study was performed to evaluate the clinical efficacy and safety of apatinib in the treatment of advanced cholangiocarcinoma after failed gemcitabine-based chemotherapy.Patients and MethodsThis was a prospective open-label phase II trial (NCT03521219). A total of 32 patients, in whom gemcitabine-based first-line chemotherapy for advanced intrahepatic cholangiocarcinoma had failed, were consecutively enrolled in a prospective, open, exploratory, and single-center clinical trial from November 2017 to November 2018. They were treated with apatinib mesylate second-line monotherapy (orally, 500 mg per day for a cycle of 28 days) until progressive disease or unacceptable toxicity. Using Response Evaluation Criteria in Solid Tumor version 1.1 (RECIST 1.1) and the Common Terminology Criteria for Adverse Events version 4.0 (NCI-CTCAE 4.0), the efficacy and adverse were evaluated, respectively. Kaplan-Meier method was used for survival analysis.ResultsTwenty-six patients were enrolled in full analysis set. At the end of follow-up, two patients were lost to follow-up, 24 of 26 patients in FAS were included in efficacy analyses. For the efficacy analysis set, the objective response rate (ORR) was 20.8% [95% confidence interval (CI): 9.24–40.47%] and the disease control rate (DCR) was 62.5% (95% CI: 112.86–387.14 days). One patient (4%) showed complete response (CR), 4 patients (17%) showed partial response (PR), 10 patients (41.7%) stable disease (SD), and 9 patients (37.5%) had progressive disease (PD). Meanwhile, apatinib therapy achieved the median progression-free survival PFS was 95 days (95% CI: 79.70–154.34 days), and the median OS was 250 days (95% CI: 112.86–387.14 days). Furthermore, univariate analysis revealed that age and tumor’s anatomic location significantly affected PFS (P < 0.05). The most common clinically adverse events (AEs) included myelosuppression (69.2%), hypertension (57.7%), proteinuria (46.2%). The AEs were mild, mainly in grade 1 or 2, and no toxicity-induced death occurred.ConclusionApatinib monotherapy is an effective and promising regimen for treating patients with advanced cholangiocarcinoma who experienced failure of gemcitabine-based chemotherapy.

128TiP HER2CLIMB-04: Phase II trial of tucatinib + trastuzumab deruxtecan in patients with HER2+ unresectable locally-advanced or metastatic breast cancer with and without brain metastases

Tucatinib (TUC) is an oral, reversible, small molecule tyrosine kinase inhibitor highly selective for human epidermal growth factor receptor 2 (HER2). In the HER2CLIMB trial (NCT02614794), the combination of TUC + trastuzumab (T) + capecitabine (C) demonstrated statistically significant and clinically meaningful improvement in progression free survival (PFS), overall survival (OS), and PFS in patients (pts) with brain metastases (BM) compared to T + C alone, supporting regulatory approvals internationally for pts with HER2+ metastatic breast cancer (MBC).

CYP3A Mediated Metabolism of Tyrosine Kinase Inhibitor Pexidartinib and Alleviated its Cytotoxicity to HepG2 Cells

Pexidartinib (PLX, TURALIOTM) is a novel small molecule tyrosine-kinase inhibitor with highly selective activity against colony-stimulating factor-1 receptor. PLX was developed for the treatment of symptomatic tenosynovial giant cell tumor in adult patients and approved by the US FDA in 2019. Despite its effectivity, frequently reported clinical cases with severe hepatotoxicity led to a black-box warning issued to PLX by the FDA. However, the mechanisms of PLX-induced hepatotoxicity remain largely unknown and the roles of PLX metabolism in its toxicity have not been investigated. Using liquid chromatography/mass spectrometry-based metabolomic approaches, this study revealed 36 PLX metabolites in human liver microsome (HLM) and mouse liver microsome (MLM), including characterized 11 glutathione (GSH) -PLX adducts and 3 methoxyamine-trapped aldehydes (hydrazones). Using recombinant cytochrome P450 enzymes, CYP3A4 and CYP3A5 were identified as the primary enzymes contributing to the formation of major metabolites, GSH-PLX adducts, and methoxyamine-trapped hydrazones. Their formation was significantly suppressed by the CYP3A inhibitor ketoconazole and in the liver S9 fraction of Cyp3a-null mice, further confirming the role of CYP3A in PLX Phase I metabolism. More interestingly, we found that PLX is less toxic to CYP3A4- or CYP3A5-overexpressed HepG2 cells compared to their counterpart HepG2 cells transduced with empty vector, indicating that CYP3A-mediated metabolism attenuates PLX cytotoxicity to HepG2. In summary, 36 PLX metabolites including 11 GSH adducts and 3 hydrazones were identified in HLM and MLM. CYP3A4 and CYP3A5 are responsible for the Phase I biotransformation of PLX and alleviate its cytotoxicity in HepG2. Further studies are warranted to elucidate the role of metabolism in PLX hepatotoxicity and the mechanism associated with PLX-induced liver injury.

MicroRNAs as Predictive Biomarkers of Resistance to Targeted Therapies in Gastrointestinal Tumors

The advent of precision therapies against specific gene alterations characterizing different neoplasms is revolutionizing the oncology field, opening novel treatment scenarios. However, the onset of resistance mechanisms put in place by the tumor is increasingly emerging, making the use of these drugs ineffective over time. Therefore, the search for indicators that can monitor the development of resistance mechanisms and above all ways to overcome it, is increasingly important. In this scenario, microRNAs are ideal candidate biomarkers, being crucial post-transcriptional regulators of gene expression with a well-known role in mediating mechanisms of drug resistance. Moreover, as microRNAs are stable molecules, easily detectable in tissues and biofluids, they are the ideal candidate biomarker to identify patients with primary resistance to a specific targeted therapy and those who have developed acquired resistance. The aim of this review is to summarize the major studies that have investigated the role of microRNAs as mediators of resistance to targeted therapies currently in use in gastro-intestinal neoplasms, namely anti-EGFR, anti-HER2 and anti-VEGF antibodies, small-molecule tyrosine kinase inhibitors and immune checkpoint inhibitors. For every microRNA and microRNA signature analyzed, the putative mechanisms underlying drug resistance were outlined and the potential to be translated in clinical practice was evaluated.

Capmatinib (Tabrecta™)

Capmatinib (Tabrecta™)

Dosing Strategies for Improving the Risk-Benefit Profile of Ponatinib in Patients With Chronic Myeloid Leukemia in Chronic Phase.

The treatment of chronic myeloid leukemia (CML) has been advanced by the development of small-molecule tyrosine kinase inhibitors (TKIs), which target the fusion protein BCR-ABL1 expressed by the Philadelphia chromosome. Ponatinib is a 3rd generation TKI that binds BCR-ABL1 with high affinity and inhibits most BCR-ABL1 mutants, including the T315I mutation. The approved starting dose of ponatinib is 45 mg once daily (full dose), however, the need for a full dose, especially in patients with dose adjustments due to tolerability problems, remains undemonstrated. Lower starting doses of ponatinib (30 mg or 15 mg once daily) for patients “with lesser degrees of resistance or multiple intolerances, especially those with an increased cardiovascular risk profile” has been recommended by the 2020 European LeukemiaNet. However, the available literature and guidance on the use of ponatinib at low dosage are limited. The objective of this paper is to describe how we select ponatinib dosage for CML patients in chronic phase in our clinical practice based on the available evidence and our clinical experience. We propose dosing regimens for the optimal starting dose for six generic cases of CML patients in chronic phase eligible for the switch to ponatinib and provide an algorithm to guide ponatinib dosing during treatment.

Role of Erlotinib in Influencing the Quality of Life of Cancer Patients

Background:: Cancer is one of the significant causes of morbidity and mortality in patients globally. Lung cancer, among other cancers, remains to be one of the principal causes of deaths in both men and women. The most common type of lung cancer is the non-small-cell lung cancer (NSCLC). Apart from lung cancer, pancreatic cancer is also one of the common cancers currently. Objective:: The assessment of QoL in erlotinib-treated patients can also prove to be very useful in the establishment of this drug as the main treatment option for the patients with pancreatic and lung cancer. Methods:: Therapies that target EGFR-mediated signalling are the latest keystones for treating these two types of cancers. They comprise of two main treatment modalities: firstly, against the extracellular fields, that include monoclonal antibodies and secondly, mechanisms that create interferences in the signalling pathways, primarily the small molecule tyrosine kinase inhibitors. Results:: Quality of life (QoL) is one of the key advantages in erlotinib therapy over chemotherapy. Conclusion:: The present review reports the role of erlotinib in improving the quality of life of cancer patients especially in NSCLC and pancreatic cancers. The studies or trials establishing the relations between erlotinib and QoL are discussed in detail in this review.

Abstract PS6-11: Targetable ERBB2 mutation status is an independent marker of adverse prognosis in estrogen receptor positive, ERBB2 non-amplified primary lobular breast carcinoma: Validation using a novel gene signature of HER2 activation

Abstract Invasive lobular carcinoma (ILC) accounts for 10-15% of primary breast cancer and is typically ER+ and ERBB2 non-amplified. There is preclinical evidence that somatic ERBB2 mutation may provide an alternative and tractable mechanism for upregulation of HER2 activity in tumors that do not express HER2 by current clinical criteria. Using large public datasets, we previously demonstrated that targetable ERBB2 mutations are enriched in ILC versus invasive ductal carcinoma (IDC) and are an independent prognostic factor in ILC (HR=3.7, 95% CI 1.2-11.0; p=0.021)*. We next hypothesized that a gene expression signature incorporating HER2 activity due to ERBB2 mutation and / or amplification would validate the prognostic signal we found in ILC. To derive a novel gene expression signature of HER2 activity that accounted for the effect of potentially targetable ERBB2 mutations in ERBB2 non-amplified tumors, we applied a weighted average difference method to gene expression data in cases from the METABRIC 2012 (N=1,980) and TCGA 2015 (N=817) cohorts. To compare our novel gene expression signature with an established signature of HER2 activity, we performed multivariate regression modeling of response to neratinib, a small molecule tyrosine kinase inhibitor of HER1, 2 and 4, using pharmacogenomic data accessed via the CellMinerCDB online portal. We show that our novel HER2 pathway signature score uniquely enriches for ERBB2 mutated tumors. Using a Cox regression model and stratifying gene expression scores into upper versus lower quartiles, we were able to validate the prognostic signal of ERBB2 mutations in ILC tumors (HR for 10-year OS in ILC=2.3, 95% CI 1.04-5.05; p=0.040). In contrast, no relationship was found between ERBB2 mutation status or novel HER2 pathway enrichment score and patient outcome in cases of IDC. We conclude that ERBB2 mutations that are enriched in ILC provide a robust biomarker of HER2 pathway activation and can be detected via gene expression signature. Novel clinical trials of HER2-targeted therapy in ERBB2 non-amplified primary ILC are warranted. *Reference: Kurozumi S et al, Cancer Research 2019, 80(4) suppl: SABCS 2019 Abstract P1-18-06 and medRxiv 2020.01.24.20018622 Citation Format: Mansour Alsaleem, Sasagu Kurozumi, Kartikeya Bhardwaj, Cintia Monteiro, Stacey EP Joosten, Andrew R Green, Takaaki Fujii, Ken Shirabe, Ian O Ellis, Emad A Rakha, Nigel P Mongan, David M Heery, Wilbert Zwart, Steffi Oesterreich, Simon J Johnston. Targetable ERBB2 mutation status is an independent marker of adverse prognosis in estrogen receptor positive, ERBB2 non-amplified primary lobular breast carcinoma: Validation using a novel gene signature of HER2 activation [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS6-11.

Abstract PS5-41: Machine learning model of gut microbiota predicts neratinib induced diarrhea in patients with breast cancer

Abstract Background: Neratinib is a potent small molecule tyrosine kinase inhibitor (TKI) of human epidermal growth factor receptors (HER1,2,4). One of the major side effects of neratinib is diarrhea. The human gut contains a dense microbiome ecosystem that is essential in maintaining a healthy host physiology, and its disruption may lead to increased risk of toxicities from cancer therapy. In this study, we aimed to develop a machine learning model based on analysis of gut microbiota data to predict neratinib-induced diarrhea. Methods: Patients were enrolled in a phase II trial evaluating safety and tolerability of neratinib in older adults with HER2+ breast cancer (NCT02673398). Neratinib was administered as single agent, 240 mg oral daily in a 28-day cycle. Stool samples were collected at baseline and during treatment for 16S rRNA gene sequencing. Using microbial relative abundance data, we developed gradient-boosted tree models with two nested loops of cross validations to classify whether diarrhea would occur or not after treatment onset. For the inner validation loop, we used ten-fold cross validation to determine the optimal model from hyper-parameters including regularization. For the outer validation loop, we utilized a leave-one-patient-out cross validation to test this model on the hold-out patient’s baseline data and the predictions were used for model assessment. Results: A total of 11 patients and 50 longitudinal stool samples were collected. The median age was 66 years. 73% developed grade ≥ 1 diarrhea attributed to neratinib. Shannon diversity index of gut microbiome was not associated with diarrhea. For predictive modeling, the outer validation loop Area Under the Receiver Operating Characteristic Curve (AUROC) and Area Under the Precision Recall Curve (AUPRC) were 0.92 and 0.97, respectively. The two most important taxa predictive of protection from diarrhea were Ruminiclostridium 9, and Bacteroides sp. HPS0048. We found that patients with a larger relative abundance of Ruminiclostridium 9 and Bacteroides sp. HPS0048 have reduced risk of neratinib-related diarrhea. Conclusions: The machine learning model can identify breast cancer patients at risk of diarrhea prior to neratinib use. Future studies are required to validate this finding. Citation Format: Chi Wah Wong, Susan E. Yost, Jin Sun Lee, John D. Gillece, Megan Folkerts, Lauren Reining, Sarah K. Highlander, Zahra Eftekhari, Joanne Mortimer, Yuan Yuan. Machine learning model of gut microbiota predicts neratinib induced diarrhea in patients with breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS5-41.

Abstract PS10-04: Tucatinib favourably modulates the immune microenvironment and synergises with anti-PD1 therapy in a trastuzumab resistant HER2+ murine model

Abstract Background: The efficacy of PD-(L)1 inhibitors in patients with trastuzumab-resistant advanced HER2+ breast cancer is poor. Although many HER2 targeted therapies are used clinically, their effect on the tumor immune microenvironment (TME) and whether this contributes to efficacy is not understood. Tucatinib is a potent, highly selective, HER2 small molecule tyrosine kinase inhibitor with proven clinical benefit in the advanced setting. Methods: We used two immunocompetent, HER2+ murine cancer models (trastuzumab-sensitive H2N113 and trastuzumab-resistant fo5) to investigate the effects of tucatinib on tumor growth kinetics, as well as tucatinib anti-tumor efficacy in combination with trastuzumab and PD-1 checkpoint blockade. Effects of tucatinib on the tumor infiltrating lymphocytes were analysed using flow cytometry. To identify genes that were modulated by tucatinib treatment, we performed bulk RNA sequencing on fo5 tumors treated with vehicle or tucatinib. We evaluated healthy donor peripheral blood T cells treated with tucatinib for 96 hours and analysed secreted cytokine levels using cytometric bead array. Results: Treatment of CD4+ and CD8+ T cells with tucatinib together with TCR stimulation resulted significantly higher levels of IFNγ and TNFα compared with stimulated controls (p &amp;lt; 0.0001), suggesting tucatinib can directly modulate human T cell function. In both murine models, tucatinib significantly inhibited tumor growth in a dose-dependent manner and was observed at doses of 25 mg/kg, 50 mg/kg and 100 mg/kg (p &amp;lt; 0.05 between each dose). Median survival was 16 days in the vehicle group vs 50 days with 100 mg/kg of tucatinib (p &amp;lt; 0.0001). Ex vivo analysis of tumors by flow cytometry showed increased infiltration of NK cells (p=0.01) and, CD8+ T cells with high PD-1 (p = 0.001), TIM-3 (p = 0.009), IFNγ (p = 0.003) and Ki67 (p = 0.0003) expression in Tucatinib treated mice compared to vehicle treated mice. Concomitant with these changes there was a significant reduction in numbers of neutrophils (p = 0.0085) and MHC-II low expressing macrophage populations (p &amp;lt; 0.0001) following tucatininb treatment with an increase in frequency of MHC-II expressing dendritic cells (p &amp;lt; 0.0001) and macrophages (p &amp;lt; 0.0001) suggesting an increase in anti-tumor immunity. Similarly, in the fo5 model tucatinib treated tumors had significantly higher interferon-γ (IFNγ) produced by CD8+ T cells (p = 0.005). Gene expression profile analysis shows significant enrichment in pathways associated with immune activation, including antigen binding and presentation (p = 0.0002), adaptive immune responses (p = 0.0002) including IFNγ (p = 0.0002) and IFNα (p = 0.0002). In this model, tucatinib in combination with trastuzumab demonstrated significantly better anti-tumor activity (p = 0.03) and survival (p &amp;lt; 0.0001) compared with tucatinib alone, with 33% of mice achieving complete tumour regressions. Tucatinib in combination with PD-1 inhibition also demonstrated significantly greater anti-tumor efficacy compared to tucatinib alone (p = 0.0079) with increased survival (p = 0.05) and 50% of mice achieving complete tumor regression. Conclusions: This study suggests an anti-tumor immune response may be an important component of the efficacy of tucatinib. This is supported by in vitro data demonstrating tucatinib stimulated human peripheral T cells and in vivo data showing favorable effects on the TME mediated by tucatinib treatment. These changes were associated with improved efficacy when tucatinib was combined with PD-1 inhibition or trastuzumab in the setting of trastuzumab resistance. These findings suggest that the combination of tucatinib and PD-1 inhibition is a rational combination that warrants investigation in the clinical setting, particularly for trastuzumab resistant HER2+ breast tumors. Citation Format: Ran Li, Sneha Sant, Emmaline Brown, Franco Caramia, Ann Byrne, Kylie Clarke, Michael Neeson, Paul J Neeson, Phillip K Darcy, Scott Peterson, Sherene Loi. Tucatinib favourably modulates the immune microenvironment and synergises with anti-PD1 therapy in a trastuzumab resistant HER2+ murine model [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS10-04.

Apatinib Plus Temozolomide: An Effective Salvage Treatment for Recurrent Glioblastoma.

BackgroundTreatment for recurrent glioblastoma is poor, and there is a need for better therapies. Here we retrospectively assessed the efficacy and toxicity of temozolomide plus apatinib, an oral small-molecule tyrosine kinase inhibitor targeting vascular endothelial growth factor receptor 2 in recurrent glioblastoma.Materials and MethodsA retrospective analysis of patients with recurrent glioblastoma who underwent apatinib plus temozolomide treatment was performed. Apatinib was given at 500 mg once daily. Temozolomide was administered at 200 mg/m2/d on days 1–5 or 50 mg/m2/d continuous daily according to whether they had experienced temozolomide maintenance treatment before. The main clinical data collected included tumor characteristics, status of MGMT promoter, and IDH mutation, number of relapse, response, survival, adverse reactions, and salvage therapies.ResultsFrom April 2016 to August 2019, thirty-one patients were identified. The objective response rate was 26.3%, and the disease control rate was 84.2%. The progression-free survival (PFS) at 6 months and overall survival (OS) at 12 months were 44.6 and 30.2%. The median PFS and OS were 4.9 and 8.2 months, respectively. Two patients achieved long PFS of 30.9 and 38.7+ months. The median survival time after progression of the patients with or without salvage bevacizumab was 5.1 versus 1.2 months. The most common grade 3 or 4 toxicities were hypertension (5.8%), decreased appetite (5.8%), and thrombocytopenia (4.3%), most of which were resolved after symptomatic treatment or dose reduction.ConclusionApatinib plus temozolomide is an effective salvage regimen with manageable toxicities for recurrent glioblastoma and could not reduce the sensitivity to bevacizumab.

CCL4-mediated targeting of spleen tyrosine kinase (Syk) inhibitor using nanoparticles alleviates inflammatory bowel disease.

Inflammatory bowel disease (IBD) has emerged a global disease and the ascending incidence and prevalence is accompanied by elevated morbidity, mortality, and substantial healthcare system costs. However, the current typical one‐size‐fits‐all therapeutic approach is suboptimal for a substantial proportion of patients due to the variability in the course of IBD and a considerable number of patients do not have positive response to the clinically approved drugs, so there is still a great, unmet demand for novel alternative therapeutic approaches. Spleen tyrosine kinase (Syk), a cytoplasmic nonreceptor protein tyrosine kinase, plays crucial roles in signal transduction and there are emerging data implicating that Syk participates in pathogenesis of several gut disorders, such as IBD. In this study, we observed the Syk expression in IBD patients and explored the effects of therapeutic Syk inhibition using small‐molecule Syk inhibitor piceatannol in bone marrow–derived macrophages (BMDMs). In addition, due to the poor bioavailability and pharmacokinetics of small‐molecule tyrosine kinase inhibitors and superiority of targeting nanoparticles‐based drug delivery system, we herein prepared piceatannol‐encapsulated poly(lactic‐co‐glycolic acid) nanoparticles that conjugated with chemokine C–C motif ligand 4 (P‐NPs‐C) and studied its therapeutic effects in vitro in BMDMs and in vivo in experimental colitis model. Our results indicated that in addition to alleviating colitis, oral administration of P‐NPs‐C promoted the restoration of intestinal barrier function and improved intestinal microflora dysbiosis, which represents a promising treatment for IBD.

DDR1 and DDR2: a review on signaling pathway and small molecule inhibitors as an anticancer agent

Cancer is the 2nd most fatal disease around the globe. Various receptors have been showed to be overexpressed and/or mutated in numerous cancers. Discoidin domain receptors 1 (DDR1) and 2 (DDR2) are one of the novel receptor tyrosine kinases (RTKs), which have been proved to regulate various cellular signaling pathways, cell proliferation, adhesion, migration, matrix remodeling, and dysregulation of these receptors may lead to metastatic cancer progressions. These receptors belong to unique category of RTKs, which require collagen binding for its activation. Yet the mechanism of this extracellular collagen binding and activation of cytosolic kinase domain of the receptors is not clear. Like other RTKs, these receptors also showed its extensive implications in numerous cancers like lung, breast, ovarian, pancreatic cancer and many others. Therefore DDR1 and DDR2 emerge as potential therapeutic targets in preventing cancer. Various small molecule tyrosine kinase inhibitors have been developed against these two receptors and proved to be highly efficacious in reducing tumor progressions. This review would highlight the detailed structure, functions, mechanism of action, signaling pathways of DDR1 and DDR2, their roles in cancer developments and the inhibition of these receptors with numerous inhibitors can be a promising strategy to combat this hefty menace.

Treatment of Brain Metastases of Non-Small Cell Lung Carcinoma.

Lung cancer is one of the most common malignant neoplasms. As a result of the disease’s progression, patients may develop metastases to the central nervous system. The prognosis in this location is unfavorable; untreated metastatic lesions may lead to death within one to two months. Existing therapies—neurosurgery and radiation therapy—do not improve the prognosis for every patient. The discovery of Epidermal Growth Factor Receptor (EGFR)—activating mutations and Anaplastic Lymphoma Kinase (ALK) rearrangements in patients with non-small cell lung adenocarcinoma has allowed for the introduction of small-molecule tyrosine kinase inhibitors to the treatment of advanced-stage patients. The Epidermal Growth Factor Receptor (EGFR) is a transmembrane protein with tyrosine kinase-dependent activity. EGFR is present in membranes of all epithelial cells. In physiological conditions, it plays an important role in the process of cell growth and proliferation. Binding the ligand to the EGFR causes its dimerization and the activation of the intracellular signaling cascade. Signal transduction involves the activation of MAPK, AKT, and JNK, resulting in DNA synthesis and cell proliferation. In cancer cells, binding the ligand to the EGFR also leads to its dimerization and transduction of the signal to the cell interior. It has been demonstrated that activating mutations in the gene for EGFR-exon19 (deletion), L858R point mutation in exon 21, and mutation in exon 20 results in cancer cell proliferation. Continuous stimulation of the receptor inhibits apoptosis, stimulates invasion, intensifies angiogenesis, and facilitates the formation of distant metastases. As a consequence, the cancer progresses. These activating gene mutations for the EGFR are present in 10–20% of lung adenocarcinomas. Approximately 3–7% of patients with lung adenocarcinoma have the echinoderm microtubule-associated protein-like 4 (EML4)/ALK fusion gene. The fusion of the two genes EML4 and ALK results in a fusion gene that activates the intracellular signaling pathway, stimulates the proliferation of tumor cells, and inhibits apoptosis. A new group of drugs—small-molecule tyrosine kinase inhibitors—has been developed; the first generation includes gefitinib and erlotinib and the ALK inhibitor crizotinib. These drugs reversibly block the EGFR by stopping the signal transmission to the cell. The second-generation tyrosine kinase inhibitor (TKI) afatinib or ALK inhibitor alectinib block the receptor irreversibly. Clinical trials with TKI in patients with non-small cell lung adenocarcinoma with central nervous system (CNS) metastases have shown prolonged, progression-free survival, a high percentage of objective responses, and improved quality of life. Resistance to treatment with this group of drugs emerging during TKI therapy is the basis for the detection of resistance mutations. The T790M mutation, present in exon 20 of the EGFR gene, is detected in patients treated with first- and second-generation TKI and is overcome by Osimertinib, a third-generation TKI. The I117N resistance mutation in patients with the ALK mutation treated with alectinib is overcome by ceritinib. In this way, sequential therapy ensures the continuity of treatment. In patients with CNS metastases, attempts are made to simultaneously administer radiation therapy and tyrosine kinase inhibitors. Patients with lung adenocarcinoma with CNS metastases, without activating EGFR mutation and without ALK rearrangement, benefit from immunotherapy. This therapeutic option blocks the PD-1 receptor on the surface of T or B lymphocytes or PD-L1 located on cancer cells with an applicable antibody. Based on clinical trials, pembrolizumab and all antibodies are included in the treatment of non-small cell lung carcinoma with CNS metastases.

A new monoclonal antibody that blocks dimerisation and inhibits c-kit mutation-driven tumour growth

PurposeImatinib, a small-molecule tyrosine kinase inhibitor, has shown good clinical activity by inhibiting adenosine triphosphate (ATP) binding to the receptor. Unfortunately, majority of patients eventually develop drug resistance, which limits the long-term benefits of the tyrosine kinase inhibitors and poses a significant challenge in the clinical management of GIST. The aim of our study was to explore the feasibility of blocking KIT dimerisation upstream of the phosphorylation in imatinib-resistant GIST.MethodKITMAb was prepared using hybridoma technique. The biological function of KITMAb was examined in KIT-dimer-expressing cells constructed by transfecting with liposomes using enzyme linked immunosorbent assay (ELISA), immunohistochemistry, western blot, MTT, Annexin V/FITC, and flow cytometry assay, respectively.ResultsKIT-dimer was expressed in 293 cells transfected with c-kit mutated-type pcDNA3.1. Treatment of KIT-dimer-expressing cells with the KITMAb significantly decreased the expression of both KIT-dimer and other phosphorylated proteins of KIT downstream signalling pathway. Furthermore, KITMAb slowed down cell growth and reduced the proportion of cells in the proliferative phase (S + G2-M). Finally, we also found that KITMAb treatment accelerated cell apoptosis. These results indicate that KITMAb strongly inhibits KIT receptor dimerisation-mediated signalling pathway and cell growth responses in vitro.ConclusionsWe demonstrate c-kit mutation-driven KIT auto-dimerisation prior to tyrosine kinase phosphorylation as same as the procedure in ligand-dependent signalling pathway and describe a monoclonal antibody, KITMAb, with strong affinity to the dimerisation domain of KIT that blocks the important step in both the KIT signalling pathways. Further, the results suggest that treatment with KITMAb may be potentially therapeutic in imatinib-resistant GIST.

Impact of STAT1 polymorphisms on crizotinib-induced hepatotoxicity in ALK-positive non-small cell lung cancer patients.

Crizotinib is the first-line small molecule tyrosine kinase inhibitor for ALK-positive non-small cell lung cancer. In this study, a retrospective pharmacogenomics investigation was conducted to explore the relationship between genes related to RTK downstream signaling pathways and crizotinib-induced hepatic toxicity in ALK-positive NSCLC patients. The variable importance analysis of random forest algorithm was applied to identify the significant features which contribute to the crizotinib sensitivity in Cancer Cell Line Encyclopedia (CCLE) database. The KEGG and reactome pathway enrichment analysis were conducted with EnrichR. The differential expression genes were identified with R package DESeq2 in CCLE liver derived cell lines between crizotinib sensitive and resistant groups. From 2012 to 2015, 42 NSCLC patients were enrolled in this study. 90 polymorphisms were genotyped using the Sequenom Massarray system. Sequencing of HGFR (c-Met) genes was carried out on the Ion Torrent Proton. In total, 66.7% NSCLC patients suffered from crizotinib-induced liver toxicity and 11.9% progressed to severe hepatic toxicity. The features with the top importance from classification and regression random forest model were enriched in RTK downstream signaling pathways (JAK/STAT, RAS/RAF/MAPK, PI3K/AKT pathways) and immune system-related pathways. Collagen family genes (COL1A1, COL1A2, COL6A1, COL5A1) and other extracellular matrix protein (TNC, TAGLN, TENM2, EDIL3, VCAN, CNN1, SH3BP4, TAGLN), which were closely related to MAPK-ERK signaling pathways, were significantly enriched in crizotinib resistant cell lines. In multiple logistic regression, STAT1 rs10208033 (T > C) was significantly associated with crizotinib-induced liver toxicity (OR = 6.733, 95% CI 1.406-32.24, P = 0.017). Compared with non-CC, OR is 5.5 (95% CI 1.219-24.81, P = 0.027) for STAT1 rs10208033 CC genotypeto develop crizotinib-induced liver toxicity. Further cell viability test in human fetal hepatocyte line, L-02, reveals that the STAT1 inhibitor might protect hepatocyte cells from the toxicity caused by crizotinib. Polymorphism of rs10208033 is a potential biomarker for predicting crizotinib-induced hepatotoxicity. These results suggest that STAT1 plays an important role in crizotinib-induced hepatotoxicity. Further studies are needed to confirm our finding and understand the underlying mechanisms.