Promising Activity In Combination Research Articles

Abstract 3443: The IAP antagonist xevinapant, in combination with high-dose cisplatin chemoradiotherapy, induces NF-kB and apoptotic pathway biomarkers in patients with high-risk locally advanced squamous cell carcinoma of the head and neck

Abstract Introduction: Inhibitor of Apoptosis Proteins (IAPs) regulate apoptosis and modulate NF-kB signaling, which in turn drives the expression of genes involved in immune and inflammatory responses. Xevinapant (XVT) (a.k.a Debio 1143) is an orally available IAP antagonist shown to enhance tumor response to radiation through the proapoptotic cytokine TNFα and caspase activation. Results from a double-blind, multicenter, randomized, phase II trial in patients with high-risk locally advanced squamous cell carcinoma of the head and neck (LA-SCCHN) revealed significant improvement in overall survival (OS), progression free survival (PFS) and duration of response with XVT in combination with high-dose cisplatin chemoradiotherapy (CRT) vs CRT alone (NCT02022098). We analyzed XVT pharmacodynamic (PD) biomarker time-concentration profiles and explored the association of PD changes over time with clinical efficacy and safety parameters. Methods: Three serum PD biomarkers were measured during cycle 1: caspase-cleaved cytokeratin 18 fragment (CKM30), a biomarker of epithelial apoptosis, MCP1 and TNFα, both NF-kB target genes. Time course changes in PD biomarker exposure, measured by their Area Under the Curve (AUC), were tested for association with clinical efficacy and safety endpoints, by linear, logistic, and Cox Proportional Hazard models. Clinical response parameters included locoregional control (LRC) at 18 months from end of treatment (EOT), PFS, duration of LRC, time to distant relapse (TTDR), OS and complete response (CR) 6 months after EOT. Results: The biomarker analysis set was composed of all patients with baseline PD assessments and at least one post-baseline measurement and included 35 and 40 patients in the XVT and placebo (PBO) arms, respectively. All three serum PD biomarkers increased upon administration of CRT + XVT during cycle 1. The increase in CKM30 and MCP1 levels was significantly higher in the CRT + XVT arm vs the CRT + PBO arm, as tested by linear mixed effect models (CKM30: p = 0.0167; MCP1: p = 0.0135). Interestingly, CKM30 AUC appeared to be correlated with response in CRT + XVT but not CRT + PBO (based on LRC at month 18 or CR at month 6). No associations between any of the three biomarkers were observed with the safety endpoints explored. Conclusions: Xevinapant has demonstrated promising activity in combination with CRT in LA-SCCHN. The outcome of the exploratory PD analyses indicates that XVT modulates NF-kB signaling, leading to serum increases in MCP1 and TNFα while further augmenting CRT-induced apoptotic marker CKM30. Our findings further characterize the mechanism of action of XVT and how it may ultimately result in enhanced clinical responses to CRT. Citation Format: Luke Piggott, Bruno Gavillet, Franck Brichory, Kathrin Gollmer, Florilene Bouisset, Gregoire Vuagniaux. The IAP antagonist xevinapant, in combination with high-dose cisplatin chemoradiotherapy, induces NF-kB and apoptotic pathway biomarkers in patients with high-risk locally advanced squamous cell carcinoma of the head and neck [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3443.

123MO BARBICAN: A randomized, phase II study to determine the contribution of ipatasertib to neoadjuvant chemotherapy plus atezolizumab in women with triple-negative breast cancer

Pathological complete response (pCR) to neoadjuvant treatment in TNBC is strongly correlated with improved EFS and OS. Randomised trials have demonstrated increased pCR rates with the addition of checkpoint inhibitors to NACT in TNBC. Preclinical evidence suggests that AKT inhibition can enhance checkpoint inhibitor efficacy. The AKT inhibitor ipatasertib (IPAT) has shown promising activity in combination with paclitaxel as 1L therapy for metastatic TNBC. BARBICAN was designed to evaluate the clinical and biological effects of adding IPAT to NACT plus atezolizumab (atezo). International phase II, randomised trial in 146 patients (pts) with newly diagnosed, non-metastatic, high risk (node+ and/or tumour size ≥2 cm) TNBC. Patients were randomised (1:1) to receive one cycle of atezo (1200mg Q3W) ± IPAT (400mg D1-14), followed by 3 cycles of atezo (840mg Q2W) + weekly paclitaxel (80mg/m2) ± IPAT (400mg D1-21), followed by 4 cycles of atezo (840mg Q2W) + dose-dense doxorubicin (60mg/m2)/cyclophosphamide (600 mg/m2). Tumour biopsies were obtained at baseline, after each treatment phase and surgery. The primary clinical endpoint was pCR rate (ypT0/is ypN0). PD-L1 expression was assessed using the SP142 assay (1% cut-off). 144 pts received treatment, IPAT (n = 72) vs no ipatasertib (no-IPAT) (n = 72). There was no difference in pCR rates between treatment groups (chemo/atezo + IPAT, 49.3%, 95%CI, 36.8%-61.8%; chemo/atezo alone, 48.5%, 95%CI, 36.2%-61.0%). For IPAT vs no-IPAT, pCR was 66.7% vs 75.0% in the PD-L1-positive population (65 pts) and 32.4% vs 25.0% in the PD-L1-negative population (70 pts). pCR in node-positive pts was 55.6% (IPAT, 51.6%, no-IPAT 59.4%) compared to 43.1% (IPAT, 47.2%, no-IPAT 38.9%) in node-negative pts. Grade 3 or higher AE rates were 73.6% in the chemo/atezo + IPAT group and 40.3% in the chemo/atezo alone group, with rash, neutropenia, ALT increase, diarrhoea and mucosits being the most common. The majority of patients required IPAT dose modifications and the dose intensity was low. Addition of IPAT to neoadjuvant atezo plus chemotherapy did not improve pCR rates. IPAT dose intensity was low due to increased toxicity.

Angiogenesis Inhibitors in Small Cell Lung Cancer.

Inhibition of angiogenesis has been demonstrated to be an efficacious strategy in treating several tumors. Vascular endothelial growth factor (VEGF) is the most important protein with proangiogenic functions and it is overexpressed in small cell lung cancer (SCLC). Bevacizumab, a monoclonal antibody directed against VEGF, showed a promising activity in combination with etoposide and cisplatin as first-line treatment of patients with extended stage (ES)-SCLC and two randomized studies confirmed that bevacizumab improved PFS, but failed to prolong OS. Instead, disappointing results have been observed with endostar, sunitinib, sorafenib, vandetanib, and thalidomide in combination with chemotherapy in the first-line setting, with sunitinib in the maintenance setting, with sunitinib, cediranib and nintedanib as single agents or ziv-aflibercept in combination with topotecan in second-line setting. Only anlotinib improved OS and PFS as third-line therapy in Chinese patients with SCLC, and it was approved with this indication in China. Future challenges are the evaluation of the role of angiogenesis inhibitors in combination with immune- checkpoint inhibitors and chemotherapy in SCLC patients and the identification of predictive biomarkers of response to both agents.

Synergy of FLT3 inhibitors and the small molecule inhibitor of LIM kinase1/2 CEL_Amide in FLT3-ITD mutated Acute Myeloblastic Leukemia (AML) cells

Patients with FLT3-ITD mutated (FLT3-ITD+) Acute Myeloid Leukemia (AML), have frequently relapsed or refractory disease and FLT3-ITD+ inhibitors have limited efficacy. Rho kinases (ROCK) are constitutively activated by FLT3-ITD+ in AML via PI3 kinase and Rho GTPase. Upon activation by ROCK, LIM kinases (LIMK) inactivate cofilin by phosphorylation which affects cytoskeleton dynamics, cell growth and apoptosis. LIMK inhibition leads to cofilin activation via dephosphorylation and activated cofilin localizes to mitochondria inducing apoptosis. Thus, we investigated the therapeutic potential of the LIMK1/2 inhibitor CEL_Amide (LIMKi) in FLT3-ITD+ AML. Expression of LIMK1/2 in FLT3-ITD+ cell lines MOLM-13 and MV-4-11 cells could be detected by RT-qPCR and at the protein level. IC50 after LIMKi monotherapy was 440 nM in MOLM-13 cells and 420 nM in MV4-11 cells. Treatment with LIMKi decreased LIMK1 protein levels and repression of inactivating phosphorylation of cofilin in FLT3-ITD+ cells. Combination experiments with LIMKi and FLT3 inhibitors including midostaurin, crenolanib and gilteritinib were synergistic for treatment of MOLM-13 cells while combinations with quizartinib were additive. Combinations of LIMKi and the hypomethylating agent azacitidine or the ROCK inhibitor fasudil were additive. In NOD-SCID mice engrafted with MOLM13-LUC cells, the FLT3 inhibitor midostaurin and LIMKi delayed MOLM13-LUC engraftment as detected by in vivo bioluminescence imaging and the LIMKi and midostaurin combination prolonged significantly survival of leukemic mice. LIMK1/2 inhibition by the small molecule CEL_Amide seems to have promising activity in combination with FLT3 inhibitors in vitro as well as in vivo and may constitute a novel treatment strategy for FLT3-ITD+ AML.

33 Poster Discussion - XL092, a multi-targeted inhibitor of MET, VEGFR2, AXL and MER with an optimized pharmacokinetic profile

Background: Receptor tyrosine kinases (RTKs) MET, VEGFR2, AXL and MER are believed to play important roles in tumor growth, vascularization, resistance to therapy and in modulating the tumor immune microenvironment. Consistent with this the multi-targeted RTK inhibitor cabozantinib, a potent inhibitor of these RTKs as well as others, has shown significant clinical activity in a variety of solid tumors, and shows promising activity in combination with checkpoint inhibitors. Cabozantinib has an extended plasma half-life which results in drug accumulation during initial dosing. We sought to develop a novel RTK inhibitor that retains the target profile of cabozantinib but with a significantly shorter clinical half-life. The profile of XL092, a compound meeting these criteria, will be presented.

Genetic Alterations in the PI3K/AKT Pathway and Baseline AKT Activity Define AKT Inhibitor Sensitivity in Breast Cancer Patient-derived Xenografts.

AZD5363/capivasertib is a pan-AKT catalytic inhibitor with promising activity in combination with paclitaxel in triple-negative metastatic breast cancer harboring PI3K/AKT-pathway alterations and in estrogen receptor-positive breast cancer in combination with fulvestrant. Here, we aimed to identify response biomarkers and uncover mechanisms of resistance to AZD5363 and its combination with paclitaxel. Genetic and proteomic markers were analyzed in 28 HER2-negative patient-derived xenografts (PDXs) and in patient samples, and correlated to AZD5363 sensitivity as single agent and in combination with paclitaxel. Four PDX were derived from patients receiving AZD5363 in the clinic which exhibited concordant treatment response. Mutations in PIK3CA/AKT1 and absence of mTOR complex 1 (mTORC1)-activating alterations, for example, in MTOR or TSC1, were associated with sensitivity to AZD5363 monotherapy. Interestingly, excluding PTEN from the composite biomarker increased its accuracy from 64% to 89%. Moreover, resistant PDXs exhibited low baseline pAKT S473 and residual pS6 S235 upon treatment, suggesting that parallel pathways bypass AKT/S6K1 signaling in these models. We identified two mechanisms of acquired resistance to AZD5363: cyclin D1 overexpression and loss of AKT1 p.E17K. This study provides insight into putative predictive biomarkers of response and acquired resistance to AZD5363 in HER2-negative metastatic breast cancer.

Abstract 1452: Development of ONCR-148, a miR-attenuated oncolytic HSV-1 designed to potently activate antitumor T cell response

Abstract Oncolytic viruses, through cancer cell-selective lysis and accompanying release of danger signals that promote immune activation, have demonstrated antitumor efficacy in monotherapy of metastatic melanoma and have shown promising activity in combination with checkpoint inhibitors. We present here the activity of ONCR-148, a recombinant oncolytic Herpes Simplex Virus (oHSV) designed to be a safe and efficacious therapy for the treatment of solid tumors. Neuron-specific miR attenuation of ICP4 gene inhibits viral replication in neurons while preserving its potent oncolytic activity in tumor cells. The antitumor potency of the virus is enhanced by incorporating in its genome a transgene expressing fibroblast activation protein (FAP)- and CD3- bispecific antibody that recruits and re-directs the cytolytic activity of T cells toward FAP-expressing stromal cells. FAP is a cell-surface serine protease that is almost exclusively found in fibroblasts within tumor stroma. However, systemic administration of a FAP-CD3 bispecific antibody was not tolerated due to the toxicity toward FAP-expressing bone marrow mesenchymal cells (Tran et al., 2013. J.Exp.Med, 210(6), 1125-1135). Thus, the local intra-tumoral delivery of FAP-CD3 is an attractive approach to promote tumor lysis and T cell activation against cancerous lesions. To test the in vivo activity of ONCR-148, as FAP is poorly expressed in syngeneic mouse tumor models, we developed a bilateral mouse FAP-expressing MC38 syngeneic colon carcinoma model (MC38-FAP), allowing to test local antitumor activity in oHSV-injected tumors and abscopal efficacy mediated by immune cells in the non-injected tumors. Intra-tumoral administration of ONCR-148 in the MC38-FAP model resulted in tumor growth inhibition of 60% (p<0.03) and 46% (p<0.01) on the injected (ipsilateral) and non-injected (contralateral) tumor, respectively. We then investigated additional transgenes that could potentiate the antitumor activity of ONCR-148. We combined in vivo ONCR-148 with ONCR-153, an oHSV armed with the NK and T cell activating cytokine IL-12 and the chemokines CXCL10 and CCL4, allowing for expansion and recruitment of T cells and antigen presenting cells in the tumor milieu. Combined intra-tumoral administration of ONCR-148 and ONCR-153 increased the antitumor response to 90% on the injected tumor (p<0.0001), leading to complete tumor remission in 5 out of 9 treated mice and to 80% on distant tumors (p<0.0001, with no complete responses observed).These data indicate that oHSV expressing bispecific antibodies, while being well tolerated, is efficacious in injected tumors and mediate systemic antitumor immune response. The efficacy can be potentiated by a local co-expression of immunostimulatory cytokines. Such data support the further development of oHSV-1 armed with CD3 bispecific antibodies for the therapy of patients with metastatic cancer. Citation Format: Agnieszka Denslow, Brian B. Haines, Michael S. Ball, Jacqueline Gursha, Daniel Wambua, Cecilia Kwong, Lingxin Kong, Allison Colthart, Prajna Behera, Peter Grzesik, Jennifer Lee, Terry Farkaly, Caitlin Goshert, Edward M. Kennedy, Lorena Lerner, Christophe Quéva. Development of ONCR-148, a miR-attenuated oncolytic HSV-1 designed to potently activate antitumor T cell response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1452.

Abstract 2931: MTX-211, a dual and selective inhibitor of EGFR and PI3 kinase, shows promising activity in combination with MEK inhibition in preclinical models of pancreatic cancer

Abstract Pancreatic cancer is one of the deadliest forms of cancer, with median 5-year survival rates less than 10%. This disease is recalcitrant to chemotherapeutic approaches and recently approved therapies afford only modest improvements in survival. KRAS is the most commonly mutated gene in pancreatic tumors with an incidence rate exceeding 90%. Despite intensive efforts, KRAS has remained undruggable. Kinases acting both upstream and downstream of RAS continue to be exploited for the development of novel agents to attenuate signaling through this critical oncogene. While EGFR and MEK inhibitor monotherapies have been evaluated in the clinic for the treatment of pancreatic cancer, efficacy has been modest despite their relevance to MAP kinase (MAPK) pathway-altered tumors. Novel therapies are urgently needed to address adaptive signaling mechanisms that diminish the effectiveness of kinase-targeted approaches. MTX-211 is a first-in-class dual inhibitor of PI3K and EGFR kinase with a promising pharmaceutical profile and proven ability to potentiate the effectiveness of MEK inhibitor therapy in KRAS mutant colorectal tumors. The present study was undertaken to extend our evaluation of MTX-211 to include pancreatic cancer model systems. We have found that MTX-211 exhibits low micromolar potency against an extensive panel of primary models of pancreatic cancer and is highly synergistic with the MEK inhibitor trametinib. Preliminary data suggest that this synergy is driven by the ability of MTX-211 to target compensatory transcriptional activation of HER3 that occurs in response to MEK inhibition. A genetically engineered KRAS and p53 mutant (KPC) mouse model was transduced with a lentiviral construct encoding a caspase reporter, which was used to show that the combination of MTX-211 and trametinib elicited a significant increase in apoptosis over single agent controls. Results from an animal study conducted with the KPC model further showed that the combination of MTX-211 and trametinib significantly slowed growth of these aggressive tumors. Employing both KPC and patient-derived xenograft models of pancreatic cancer, efforts are underway to optimize therapeutic outcome in response to MTX-211-based combination treatment regimens. Citation Format: Christy Frankowski-McGregor, Joel Maust, Elizabeth Ziemke, Rachel Mumby, Amy Delaney, Alnawaz Rehemtulla, Christopher Whitehead, Judith S. Sebolt-Leopold. MTX-211, a dual and selective inhibitor of EGFR and PI3 kinase, shows promising activity in combination with MEK inhibition in preclinical models of pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2931.

Epacadostat Shows Value in Two SCCHN Trials.

In the ECHO-202/KEYNOTE-037 and ECHO-204 trials reported at the 2017 Annual Meeting of the American Society of Clinical Oncology, patients with squamous cell carcinoma of the head and neck responded well to the combinations of epacadostat plus pembrolizumab and epacadostat plus nivolumab. An IDO1 inhibitor, epacadostat also demonstrated promising activity in combination with the PD-1 checkpoint inhibitors in other solid tumors, including melanoma, urothelial carcinoma, renal cell carcinoma, and non-small cell lung cancer.

The role of neratinib in HER2-driven breast cancer

Up to 25% of patients with early-stage HER2+ breast cancer relapse despite adjuvant trastuzumab-based regimens and virtually all patients with metastatic disease eventually die from resistance to existing treatment options. In addition, recent studies indicate that activating HER2 mutations without gene amplification could drive tumor growth in a subset of HER2-negative breast cancer that is not currently eligible for HER2-targeted agents. Neratinib is an irreversible HER kinase inhibitor with activity as extended adjuvant therapy following standard trastuzumab-based adjuvant treatment in a Phase III trial. Phase II trials of neratinib demonstrate promising activity in combination with cytotoxic agents in trastuzumab resistant metastatic HER2+ breast cancer, and either as monotherapy or in combination with fulvestrant for HER2-mutated breast cancers. We anticipate a potential role for neratinib in the therapy of these patient populations.

Abstract OT2-01-02: COLET: A multistage, phase 2 study evaluating the safety and efficacy of a doublet regimen of cobimetinib (C) in combination with paclitaxel (P) or triplet regimens of C in combination with atezolizumab (atezo) plus either P or nab-paclitaxel (nab-P) in metastatic triple-negative breast cancer (TNBC)

Abstract Preclinical data suggest that upregulation of the MAPK pathway confers resistance to taxane chemotherapy. Mutations and gene amplifications in the MAPK pathway are present in many TNBC tumors and may contribute to taxane resistance. Preliminary data from an initial safety run-in stage of the COLET study (ClinicalTrials.gov ID, NCT02322814; EudraCT number, 2014-002230-32) suggest improvement of clinical outcomes when MEK inhibition is combined with taxane chemotherapy. Additionally, in preclinical models, MEK inhibition was shown to enhance anti–PD-L1 activity. The monoclonal antibody PD-L1 inhibitor atezo has shown promising activity in combination with nab-P in metastatic TNBC. Accordingly, the COLET protocol was amended to include the evaluation of triplet regimens combining atezo with MEK inhibition and taxane chemotherapy[SL1] . COLET is evaluating the safety and efficacy of various combinations of C as first-line treatment for metastatic or locally advanced TNBC. Key eligibility criteria include measurable disease per Response Evaluation Criteria in Solid Tumors, version 1.1 (RECIST v1.1) and left ventricular ejection fraction > institutional lower limit of normal or >50%. Neoadjuvant or adjuvant therapy is allowed if completed >6 months prior to study entry. COLET has 3 cohorts: I, II, and III. Cohort I has 2 stages: an initial safety run-in stage (n∼12) followed by an expansion stage (n∼90) of 1:1 randomization to C + P or placebo (PBO) + P. Patients received P 80 mg/m2 on days 1, 8, and 15 and C/PBO 60 mg/day on days 3-23 of each 28-day cycle. In the expansion stage of Cohort I, randomization is stratified by prior neoadjuvant/adjuvant taxane therapy and disease-free interval from last chemotherapy dose. Cohorts II and III will evaluate the safety and efficacy of adding atezo to C + P or nab-P, respectively. Each cohort has a safety run-in stage (n∼15) and an expansion stage (additional n∼15); each will receive atezo 840 mg on days 1 and 15 and C 60 mg/day on days 3-23 of every 28-day cycle. Cohort II will receive P 80 mg/m2 and Cohort III will receive intravenous nab-P 100 mg/m2 on days 1, 8, and 15. Patients will receive treatment until disease progression or toxicity. The primary efficacy end point is investigator-assessed progression-free survival (PFS) for the expansion stage (Cohort I), and the primary PFS analysis will be performed when 60 PFS events occur across the 2 arms. This provides 77% power to detect a hazard ratio of 0.5 at a two-sided significance level of 0.05. For Cohorts II and III, the primary efficacy end point is overall response rate per RECIST v1.1; secondary end points include duration of response, PFS, and overall survival. Recruitment into the safety run-in stage of Cohort I is complete. Accrual into the randomization stage of Cohort I and the initial safety run-in stage of Cohorts II and III are ongoing. Patients from sites across North America, Europe, and the Asia-Pacific region will be enrolled. Citation Format: Miles D, Kim S-B, McNally V, Simmons B, Wongchenko M, Xu N, Brufsky A. COLET: A multistage, phase 2 study evaluating the safety and efficacy of a doublet regimen of cobimetinib (C) in combination with paclitaxel (P) or triplet regimens of C in combination with atezolizumab (atezo) plus either P or nab-paclitaxel (nab-P) in metastatic triple-negative breast cancer (TNBC) [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr OT2-01-02.

Abstract 3039: Lurbinectedin specifically targets transcription in cancer cells, triggering DNA breaks and degradation of phosphorylated Pol II

Abstract Cancer cells are characterized for their avid demand for active transcription, which reaches the level of a real addiction in solid tumors as small cell lung cancer (SCLC) or triple-negative breast cancer. Pharmacological modulation of transcription may thus provide a therapeutic approach to treat tumor types that depend on deregulated transcription for the maintenance of their oncogenic state. Lurbinectedin, currently under evaluation in a Phase III clinical trial for platinum-resistant ovarian cancer patients, and with very promising activity in combination with doxorubicin in SCLC, inhibits active transcription. Here we demonstrate that, after binding to specific DNA triplets highly represented in the CG-rich region surrounding the promoter of genes, this drug induces a rapid degradation of RNA Polymerase II (Pol II). Our results show that the hyperphosphorylated form of Pol II, already engaged in transcription elongation and likely blocked during this process by the lurbinectedin-DNA adduct, is then specifically submitted to the ubiquitin/proteasome degradation process, which finally removes the majority of the Pol II protein pool in treated cells. Disappearance of Pol II is followed by the formation of DNA breaks, process in which the nucleotide excision repair (NER) machinery, specifically the endonuclease XPF, has an important role. Pol II degradation and subsequent DNA damage were not only abrogated by inhibitors of CDK7 and CDK9 cyclin dependent kinases (DRB and flavopyridol), ubiquitin ligation (PYR-41), or proteasome activity (MG132), but also correlated with the antiproliferative activity of lurbinectedin in different cancer cell line models. In summary, lurbinectedin exemplifies a prototype drug for targeting transcriptional dependency in tumor cells and, thus, it could represent a new therapeutic alternative for solid tumors with this addiction. Citation Format: Gema Santamaria-Nunez, Carlos M. Genes-Robles, Juan F. Martínez-Leal, Carlos M. Galmarini, Jean Marc Egly. Lurbinectedin specifically targets transcription in cancer cells, triggering DNA breaks and degradation of phosphorylated Pol II. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3039.

New developments in the management of chronic lymphocytic leukemia: role of ofatumumab.

Ofatumumab is one of the three anti-CD20 monoclonal antibodies currently available for the treatment of chronic lymphocytic leukemia (CLL). The US Food and Drug Administration (FDA) approved the use of ofatumumab in patients with CLL refractory to fludarabine and alemtuzumab in 2009, and the European Medicines Agency (EMA) granted approval for the same indication in 2010. Subsequent positive results of ofatumumab in combination with chlorambucil in treatment-naïve patients led the FDA in April 2014 to approve the use of this combination for first-line treatment of patients with CLL for whom fludarabine-based therapy is considered inappropriate. Later that year, the EMA approved the use of ofatumumab in combination with chlorambucil or bendamustine for the same indication. Ofatumumab has also shown potential as maintenance therapy for patients with relapsed CLL; an application to broaden the label for ofatumumab as maintenance therapy was submitted earlier this year to the EMA and FDA. Finally, ofatumumab has shown promising activity in combination with ibrutinib or idelalisib in relapsed/refractory CLL patients; combinations of ofatumumab with B-cell-receptor pathway inhibitors could represent another potential use of this antibody in the near future.

Abstract 739: The MEK-inhibitor pimasertib in B-cell lymphomas: Evaluation of the pre-clinical activity as single agent or in combination and identification of biomarkers of response

Abstract Treatment of patients with lymphomas resistant/refractory to standard chemotherapy is challenging. Development and identification of new compounds targeting components of relevant pathways is needed. Pimasertib is a potent and highly selective ATP noncompetitive MEK1/2 inhibitor, which has been shown able to induce G1 cell cycle arrest and apoptosis in different pre-clinical cancer models and potent antitumor activity in xenograft models with mainly BRAF and KRAS activating mutations. Here, we report data on the evaluation of pimasertib in a large panel of B-cell lymphoma cell lines. Methods. Cell lines from diffuse large B-cell lymphoma (DLBCL, n=16), mantle cell lymphoma (MCL, n=4), splenic marginal zone lymphoma (SMZL, n=3) underwent 72 hrs exposure to increasing doses of pimasertib (EMD Merck KGaA, Darmstadt, Germany) to assess anti-proliferative activity by MTT assay. Apoptosis was assessed by Annexin-V/7-AAD staining, gene expression profiling (GEP) with Illumina HumanHT-12 Expression BeadChips at baseline on all the cell lines. GEP/IC50 correlation was assessed by Spearman correlation. Cell lines with IC50 < 15μM were defined as sensitive; data mining included LIMMA, GSEA and Metacore. Three DLBCL cell lines were exposed to increasing doses of pimasertib in combination with other drugs, and synergy was assessed by Chou-Talalay combination index (CI). Results. The median IC50 value was 26.1 μM (range, 1.4-100 μM). The effect was largely cytostatic, with apoptosis detected in 1/5 cell lines and only at high doses (80 μM). DLBCL and SMZL cells appeared more sensitive than MCL (P=0.047 and P=0.039). No differences were observed between germinal center B-cell or activated B-cell (ABC) DLBCL. TP53 (P=0.0283) and TNFAIP3 (P=0.012) inactivation negatively affected the response to pimasertib. Transcripts significantly associated with higher sensitivity to pimasertib were enriched of MEK and RAS regulated genes, E2F target genes, genes expressed in germinal center B cells. Transcripts associated with resistance were enriched of IFN target genes (including TNFAIP3) and genes down-regulated in the presence of active MEK or RAS. Pimasertib showed synergism combined with PI3K inhibitor idelalisib (median CI=0.34), and the effect was strong in 2/3 cell lines (OCI-Ly10, CI= 0.03; TMD8, CI= 0.25). Synergism was observed with BTK-inhibitor ibrutinib in the ABC-DLBCL cell lines (OCI-Ly10, CI=0.32; TMD8, CI=0.63). Less synergistic effects were observed with pimasertib in combination with anti-CD20 moAb rituximab (CI=0.78) and with MDM2 inhibitor nutlin-3 (CI=0.67). Conclusions. Pimasertib showed promising activity in combination with PI3K and BTK inhibitors in preclinical models of mature lymphomas, worth of being further evaluated. GEP signatures associated with the response to pimasertib were identified. Citation Format: Eugenio Gaudio, Ivo Kwee, Chiara Tarantelli, Elena Bernasconi, Andrea Rinaldi, Luciano Cascione, Maurilio Ponzoni, Anastasios Stathis, Emanuele Zucca, Samantha Goodstal, Francesco Bertoni. The MEK-inhibitor pimasertib in B-cell lymphomas: Evaluation of the pre-clinical activity as single agent or in combination and identification of biomarkers of response. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 739. doi:10.1158/1538-7445.AM2014-739

Icotinib and whole brain radiotherapy (WBRT) for patients with brain metastases from non-small cell lung cancer (NSCLC): Preliminary results of a phase II study.

e19073 Background: Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs), such as gefitinib and erlotinib, have shown efficacy in advanced NSCLC with brain metastases (BM). Icotinib is a new EGFR-TKI. A randomized, double blind phase III trial proved that icotinib was non-inferior to gefitinib in advanced NSCLC. We have conducted a phase II study to evaluate the efficacy and safety of icotinib in combination with WBRT in Chinese NSCLC patients with BM. Methods: From January 2012 to January 2013, 20 patients aged 18-75 years with ECOG PS 0-2 and BM from NSCLC,were recruited regardless of EGFR status. The treatment comprised icotinib 125mg, TID concurrently with WBRT (30Gy/10f/2w). CSF and plasma samples were collected at the same time from 10 patients at least 5 days after icotinib treatment. The concentrations of icotinib in the CSF and plasma were measured by high performance liquid chromatography coupled with tandem mass spectrometry. The primary end point was progression-free survival (PFS) . Additional end points were response rate, safety and CSF concentrations of icotinib. Results: The median PFS was 7.3 months [95% confidence interval (CI) 4. 2-9.8]. Patients with EGFR mutation-positive disease had significantly longer median PFS versus EGFR wild-type disease [NR versus 4.2 months (95% CI 2.9-5.1); P = 0.000]. The CNS response rates were 25% complete response (n=5), 55% partial response (n= 11), 15% stable disease (n=3), and 5% progressive disease (n =1). The overall CNS response rate was 80% (n = 16). The most common adverse events were rash (40.0%), diarrhea (15.0%),nausea (45.0%), vomiting (20.0%), headache (35.0%)and fatigue (45.0%). And no patient experienced grade ≥ 3 toxicity. The mean plasma and CSF concentrations of icotinib were 936.47 ± 503.80 and 8.93 ± 8.01 ng/ml, respectively, and the mean ratio of CSF-plasma concentration was 1.04% ± 0.95. Conclusions: Icotinib was well tolerated and showed promising activity in combination with WBRT in patients with BM from NSCLC. The concentrations of icotinib in CSF were low. Further randomized trials are warranted. Clinical trial information: NCT01514877.

Fludarabine combined with radiotherapy in patients with locally advanced NSCLC lung carcinoma: a phase I study

Background and purposeFludarabine is an adenine nucleoside analogue that has significant activity in hematological malignancies and has shown promising activity in combination with radiation in preclinical solid tumor models. We designed a phase I trial exploring concurrent fludarabine and radiotherapy in patients with advanced non-small cell lung cancer (NSCLC) to determine the maximum tolerated dose (MTD) of fludarabine given with concurrent irradiation.Materials and methodsThirteen patients with stage IIIB NSCLC received thoracic irradiation of 60 Gy. Fludarabine was administered during the 5th and 6th week of radiotherapy. Doses started at 10 mg/m2 per day and increased by steps of 3 mg/m2 per day.ResultsAt a daily dose of 16 mg/m2, one out of six patients developed a grade 4 leukopenia, and one a grad 3 pneumonitis. Further grade III toxicity was not observed. The dose of 13 mg/m2 was identified as the MTD. All patients developed a fludarabine dose-dependent lymphocytopenia.ConclusionFludarabine can be safely administered concurrently with radiation at a daily dose of 13 mg/m2 during the final 2 weeks of radiotherapy. Further prospective clinical studies are required to establish the potential role of concurrent fludarabine and radiotherapy in the treatment of locally advanced inoperable NSCLC.

Mesothelioma and Small Cell Lung Cancer

In the mesothelioma section, two presentations were given. First, Dr. Donington delivered an overview of the most common targeted pathways and agents studied in malignant pleural mesothelioma (MPM). As described, the current front-line standard of care for unresectable MPM patients remains platinum pemetrexed, and numerous targeted agents have been investigated in combination with front-line chemotherapy and in the salvage setting. Although mesothelioma has the highest secreted levels of VEGF of any solid tumor, adding bevacizumab to cisplatin-gemcitabine did not improve PFS or OS in the ITT population from a large phase II randomized trial. 1 Nevertheless, targeting the VEGF pathway may still be relevant in MPM, because patients with serum VEGF levels below the median who received bevacizumab had a superior OS (p 0.028). In the salvage setting, several phase I and II studies that targeted angiogenesis (VEGFR, PDGFR), EGFR, TRAILR1,2, Bcl-2, tRNA, immunotherapy, and mesothelin were discussed. In general, only modest results from these studies (negative results from the monotherapy EGFR tyrosine kinase inhibitor and imatinib mesylate studies) were reported. In terms of promising new agents under investigation, a large international phase III trial of vorinostat versus placebo in second- and third-line therapy was discussed. 2 This trial has completed its accrual of 660 patients and will have the results presented later this year. If positive, this will potentially alter the treatment landscape in the salvage setting for MPM. In the second presentation, a phase I neoadjuvant dasatinib trial being conducted at MDACC was presented. This study is the first neoadjuvant targeted therapy study to be conducted in MPM and consists of tissue harvesting from multiple areas of the tumor at two time points, before and after 4 weeks of neoadjuvant dasatinib therapy. The preliminary results suggest that Src kinase Tyr419 IHC overexpression may be a valid biomarker at baseline that predicts for a response to dasatinib therapy and is a consistent pharmacodynamic marker. 3 A phase I trial in the unresectable MPM patients using cisplatin-pemetrexed-imatinib mesylate was presented which seemed to stabilize the cancer more than achieve a response. Nevertheless, this trial provided the rationale for SWOG 0905, a phase I/II trial in chemonaive MPM patients evaluating cisplatin-pemtrexed cediranib (VEGFR, PDGFR inhibitor). S0905 is open for enrollment and has completed the phase I portion and has established the phase II cediranib dose as 20 mg po daily. Small Cell Lung Cancer Although standard therapy for extensive stage SCLC remains chemotherapy, several new therapeutic approaches for SCLC are currently under investigation. VEGFR pathway inhibitors SCLC is known to overexpress ligands for the VEGF and PDGF receptors and frequently harbor c-KIT amplifications. Cediranib, an inhibitor of all three receptor tyrosine kinases, is being investigated in combination with etoposide and cisplatin (EP) chemotherapy. In phase I testing, cediranib demonstrated promising activity in combination with EP, with a median progression-free survival of 8.9 months and a objective response rate of 70%, results that compare favorably with historical controls. A phase II/III trial is currently in development. In phase II, promising activity has also been observed for bevacizumab in combinations with EP 4 or irinotecan/carboplatin. 5 BCL-2 inhibitors BCL-2 is frequently overexpressed in SCLC and is associated with resistance to chemotherapy-induced apoptosis. The BCL-2 inhibitor ABT-263 was tested in patients with SCLC and other solid tumors. Among 29 patients with SCLC or pulmonary carcinoid, one patient had a durable partial response, whereas eight had prolonged stable disease. Progastrin-releasing peptide was identified as a surrogate for Bcl-2 amplification. ABT-263 is currently undergoing further testing in combination with EP.

Gemtuzumab ozogamicin in non-acute promyelocytic acute myeloid leukemia

Introduction:Gemtuzumab ozogamicin (GO) has been used in relapsed, refractory and newly diagnosed acute myeloid leukemia (AML) as a single agent and in combination with intensive chemotherapy. Results of recent Phase III trials have led to its withdrawal in the USA although a beneficial effect of GO in genetically defined AML subgroups was evident.Areas covered:This review examines the use of GO as a single agent or in combination with intensive chemotherapy in non-acute promyelocytic AML. The literature search was based on publications on GO indexed in the PubMed electronic database and selected meeting abstracts. GO has shown moderate activity as a single agent but promising activity in combination with intensive chemotherapy in refractory or relapsed AML. Relapsed AML defined molecularly by mutant nucleophosmin-1 without concurrent fms-related tyrosine kinase 3 (FLT3) internal tandem duplication seems to benefit most from GO. In newly diagnosed AML two up-front randomized Phase III trials evaluating GO in induction therapy failed to demonstrate an improvement in response and survival. Again, genetically defined subgroups may benefit.Expert opinion:Future challenges of personalized therapy in AML will be to integrate the signals from current subgroup analyses underlining the role of GO in genetically defined AML entities.

Abstract 4911: Molecular investigation of the FTI/Taxol synergy using an integrated framework of transcriptome analysis

Abstract Farnesyltransferase inhibitors (FTIs) are a class of anticancer drugs that have exhibited modest activity in the clinic as single agents, but were found to have promising activity in combination with the microtubule-stabilizing drug Taxol (TX), both in vitro and in vivo. Clinical trials with an FTI/TX combination have demonstrated a clinical benefit for a subset of patients refractory to previous taxane-treatment. However, the precise cellular machinery underlying the FTI/TX synergistic drug combination still needs to be elucidated. To this end, we undertook an unbiased experimental/computational approach designed to identify the key cellular components that either contribute to or drive the therapeutic synergy of this drug combination. The approach combined (i) measurements of drug-mediated changes on tubulin biomarkers and overall survival; (ii) whole-genome transcriptome analysis using the combination index drug synergy algorithm; (iii) utilization of interaction and functional databases to identify pathway connections and (iv) a reverse-engineering forward simulation (REFS) approach to identify genes that drive synergy. Drug-induced transcriptome changes were examined using whole-genome Affymetrix HGU133 Plus 2 microarrays. Gene changes deemed significant using a fold change criterion, identified as synergistic with the combination index analysis, and their biological relevance was assessed by experimental validation by qPCR and siRNA studies. Also, the transcriptome changes unique to the LNF/TX combination were evaluated in the context of detailed molecular interaction maps and groups of biological function. Our analyses identified several major network hubs that include: (i) overexpression of the class II β-tubulin isotype TUBB2A and of several heat shock protein such as HSP40 and HSP70 and (ii) synergistic overexpression of cell cycle genes CDKN1A and MDM2 (iii) through REFS modeling, prosaposin and granulin were identified as drivers of drug synergy (iv) induction of the focal adhesion molecule paxillin (PXN). Interestingly, stable knockdown of protein farnesyltransferase mimicked the effects of FTI treatment and resulted in strong substratum attachment and migration defects suggesting that PXN could be regulated by farnesyltransferase and its pharmacologic inhibitors. Ultimately, we plan to check the expression levels of the key genes in tumor biopsies from patients enrolled in the Phase 1 FTI/Taxotere clinical trial and correlate their expression in pre- and post-treatment biopsies with clinical response to the combination chemotherapy. Herein, we demonstrate a combined experimental and computational approach that includes functional analysis, data-driven simulation and experimental validation, and its power to identify key cellular components, both known and novel, in the anticancer activity of drug combinations exhibiting therapeutic synergy. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4911. doi:10.1158/1538-7445.AM2011-4911

Abstract 115: An integrated framework of transcriptome analysis leads to mechanistic insights into the FTI/Taxol synergy

Abstract A novel class of anticancer agents, the farnesyltransferase inhibitors (FTIs), has exhibited modest activity in the clinic as single agents, but was found to have promising activity in combination with the microtubule-stabilizing drug Taxol (TX), both in vitro and in vivo models. Recent phase I and II oncology clinical trials with an FTI/TX combination have demonstrated a clinical benefit for a subset of patients refractory to previous taxane-treatment. However, the precise cellular machinery underlying the FTI/TX synergistic drug combination still needs to be better understood. To this end, we undertook an unbiased experimental/computational approach that combined (i) measurements of drug-mediated changes on tubulin biomarkers and overall survival; (ii) whole-genome transcriptome analysis; (iii) utilization of interaction and functional databases to identify functional and pathway connections, (iv) computational modeling and prediction based on an in silico model predictive of drug synergy. Drug-induced transcriptome changes were examined using whole-genome Affymetrix HGU133 Plus 2 microarrays. The raw data were analyzed using two global statistical analysis methods (ANOVA and SAM). Gene changes that passed both tests, using a fold change criterion, were deemed significant and subjected to experimental validation by qPCR and siRNA. The transcriptome changes that were unique to the LNF/TX combination were evaluated in the context of detailed molecular interaction maps and groups of biological function. Our analyses identified several major network hubs that include: (i) repression of the mitotic spindle-checkpoint kinase, polo-like kinase 1 (Plk1) which is also implicated in carcinogenesis and was shown to directly bind and phosphorylate α- and β-tubulins. (ii) overexpression of CDKN1A and MDM2, both of which are shown to be inversely regulated by Plk1; (iii) overexpression of the class II beta tubulin isotype TUBB2A and of several heat shock protein such as HSPA1A and DNAJB9 and (iv) induction of the focal adhesion molecule paxillin (PXN). Interestingly, stable knockdown of protein farnesyltransferase mimicked the effects of FTI treatment and resulted in strong substratum attachment and migration defects suggesting that paxillin could be regulated by farnesyltransferase and its pharmacologic inhibitors. Functional studies to elucidate this mechanism are currently underway. In summary, we demonstrate a combined experimental and computational approach that includes functional analysis, data-driven simulation and experimental validation, and its power to identify key cellular components, both known and novel, in the anticancer activity of drug combinations exhibiting therapeutic synergy. (Supported by NCI P50 CA128613 & P01 CA116676) Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 115.