Safety and tolerability of oral vorolanib for neovascular (wet) age-related macular degeneration: a phase I, open-label study.

OBJECTIVE: To evaluate the efficacy and safety of oral vorolanib for the treatment of neovascular (wet) age-related macular degeneration (nAMD). METHODS: In the dose escalation, participants received ascending doses of oral vorolanib (25-100 mg daily). In the dose expansion, participants received recommended doses (25 and 50 mg daily). RESULTS: Between March 15, 2015, and January 23, 2019, 41 participants were enrolled in 6 centres in China. At the data cut-off (November 14, 2019), two dose-limiting toxicities (DLTs) were observed during dose escalation (one in the 75 mg cohort and one in the 100 mg cohort). The maximum tolerated dose was not reached. Treatment-related adverse events (TRAEs) occurred in 33 (80.5%) participants, and grade 3 or higher TRAEs occurred in 12 (29.3%) participants. No fatal TRAEs were observed. Increases in the mean best-corrected visual acuity (BCVA) from baseline to Day 360 of +7.7 letters (range, -5-29; n = 41) were observed in participants who were administered vorolanib. Corresponding reductions in mean central subfield thickness (CST) and choroidal neovascularization (CNV) area at Day 360 were observed in these three groups. CONCLUSIONS: Oral administration of vorolanib improved visual outcomes in participants with nAMD with manageable systemic safety profiles.

Phase 1b trial of anti-VEGF/PDGFR vorolanib combined with immune checkpoint inhibitors in patients with advanced solid tumors.

PURPOSE: Vorolanib is a multi-target tyrosine kinase inhibitor with anti-angiogenic properties. This study aimed to evaluate the tolerability, safety and efficacy of vorolanib when added to checkpoint inhibitors (CPIs) in patients with advanced solid tumors. METHODS: We conducted a phase 1b study of vorolanib (300 or 400 mg orally once daily) plus pembrolizumab or nivolumab using a standard 3 + 3 design to determine the dose-limiting toxicity (DLT), maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D). The endpoints included safety, toxicity and objective response rate, according to Response Evaluation Criteria in Solid Tumors, version 1.1 (RECIST 1.1). RESULTS: Sixteen patients (9 in pembrolizumab arm, 7 in nivolumab arm) with gastrointestinal or lung cancers were enrolled. All patients had at least 1 treatment-related adverse event (TRAE). The most common TRAEs across all cohorts were lymphopenia (n = 7), leukopenia (n = 5), fatigue (n = 5), and alanine aminotransferase elevation (n = 5); most toxicities were grade (G) 1-2. DLTs were reported in 3 patients at vorolanib 400 mg dose level, with G3 aspartate aminotransferase elevation, G3 rectal hemorrhage, and G3 rash. Of 13 total response-evaluable patients, 2 patients had confirmed partial responses (1 rectal squamous cell cancer and 1 small cell lung cancer). Two patients achieved prolonged stable disease. Vorolanib 300 mg daily was determined to be the RP2D for either pembrolizumab or nivolumab. CONCLUSION: Combination vorolanib 300 mg orally once daily plus CPI appears to be a feasible regimen with manageable toxicity and promising efficacy in select tumor types. NCT03511222. Date of Registration: April 18, 2018.

Vorolanib, a novel tyrosine receptor kinase receptor inhibitor with potent preclinical anti-angiogenic and anti-tumor activity.

Vorolanib (CM082) is a multi-targeted tyrosine kinase receptor inhibitor with a short half-life and limited tissue accumulation that has been shown to reduce choroidal neovascularization in rats. In this preclinical study, vorolanib demonstrated competitive binding and inhibitory activities with KDR, PDGFRß, FLT3, and C-Kit, and inhibited RET and AMPKα1 more weakly than sunitinib, indicating more stringent kinase selectivity. Vorolanib inhibited vascular endothelial growth factor (VEGF)-induced proliferation of human umbilical vein endothelial cells (HUVECs) and HUVEC tube formation in vitro. In mouse xenograft models, vorolanib inhibited tumor growth of MV-4-11, A549, 786-O, HT-29, BxPC-3, and A375 cells in a dose-dependent fashion. Complete tumor regression was achieved in the MV-4-11 xenograft model. No significant toxicities were observed in vorolanib groups, whereas a significant negative impact on body weights was observed in the sunitinib group at a dose of 40 mg/kg qd. Overall, vorolanib is a novel multi-kinase receptor inhibitor with potent preclinical anti-angiogenic and anti-tumor activity that is potentially less toxic than other similar kinase inhibitors.

Ensartinib vs Crizotinib for Patients With Anaplastic Lymphoma Kinase-Positive Non-Small Cell Lung Cancer: A Randomized Clinical Trial.

IMPORTANCE: Ensartinib, an oral tyrosine kinase inhibitor of anaplastic lymphoma kinase (ALK), has shown systemic and central nervous system efficacy for patients with ALK-positive non-small cell lung cancer (NSCLC). OBJECTIVE: To compare ensartinib with crizotinib among patients with advanced ALK-positive NSCLC who had not received prior treatment with an ALK inhibitor. DESIGN, SETTING, AND PARTICIPANTS: This open-label, multicenter, randomized, phase 3 trial conducted in 120 centers in 21 countries enrolled 290 patients between July 25, 2016, and November 12, 2018. Eligible patients were 18 years of age or older and had advanced, recurrent, or metastatic ALK-positive NSCLC. INTERVENTIONS: Patients were randomized (1:1) to ensartinib, 225 mg once daily, or crizotinib, 250 mg twice daily. MAIN OUTCOMES AND MEASURES: The primary end point was blinded independent review committee-assessed progression-free survival (PFS). Secondary end points included systemic and intracranial response, time to central nervous system progression, and overall survival. Efficacy was evaluated in the intent-to-treat (ITT) population as well as a prespecified modified ITT (mITT) population consisting of patients with central laboratory-confirmed ALK-positive NSCLC. RESULTS: A total of 290 patients (149 men [51.4%]; median age, 54 years [range, 25-90 years]) were randomized. In the ITT population, the median PFS was significantly longer with ensartinib than with crizotinib (25.8 [range, 0.03-44.0 months] vs 12.7 months [range, 0.03-38.6 months]; hazard ratio, 0.51 [95% CI, 0.35-0.72]; log-rank P < .001), with a median follow-up of 23.8 months (range, 0-44 months) for the ensartinib group and 20.2 months (range, 0-38 months) for the crizotinib group. In the mITT population, the median PFS in the ensartinib group was not reached, and the median PFS in the crizotinib group was 12.7 months (95% CI, 8.9-16.6 months; hazard ratio, 0.45; 95% CI, 0.30-0.66; log-rank P < .001). The intracranial response rate confirmed by a blinded independent review committee was 63.6% (7 of 11) with ensartinib vs 21.1% (4 of 19) with crizotinib for patients with target brain metastases at baseline. Progression-free survival for patients without brain metastases was not reached with ensartinib vs 16.6 months with crizotinib as a result of a lower central nervous system progression rate (at 12 months: 4.2% with ensartinib vs 23.9% with crizotinib; cause-specific hazard ratio, 0.32; 95% CI, 0.16-0.63; P = .001). Frequencies of treatment-related serious adverse events (ensartinib: 11 [7.7%] vs crizotinib: 9 [6.1%]), dose reductions (ensartinib: 34 of 143 [23.8%] vs crizotinib: 29 of 146 [19.9%]), or drug discontinuations (ensartinib: 13 of 143 [9.1%] vs crizotinib: 10 of 146 [6.8%]) were similar, without any new safety signals. CONCLUSIONS AND RELEVANCE: In this randomized clinical trial, ensartinib showed superior efficacy to crizotinib in both systemic and intracranial disease. Ensartinib represents a new first-line option for patients with ALK-positive NSCLC. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02767804.

Vorolanib, an oral VEGFR/PDGFR dual tyrosine kinase inhibitor for treatment of patients with advanced solid tumors: An open-label, phase I dose escalation and dose expansion trial.

OBJECTIVE: This study evaluated the safety and preliminary efficacy of vorolanib, a novel tyrosine kinase inhibitor, for treatment of patients with advanced solid tumors. METHODS: During dose escalation, patients received increasing doses of oral vorolanib (50-250 mg once daily) in cycles of four weeks for up to one year. During dose expansion, patients received recommended doses (100 and 200 mg) in 4-week cycles. The primary endpoint was to determine the safety and maximum tolerated dose and/or the recommended phase II dose (RP2D). The severity and type of adverse drug reactions (ADRs) were assessed using the Common Terminology Criteria for Adverse Events version 4.0. The second endpoint was preliminary efficacy in terms of objective response and progression-free survival (PFS). RESULTS: No dose-limiting toxicity occurred during dose escalation (50-250 mg). Five (26.3%) patients in the escalation cohort (n=19) and 12 (48.0%) in the expansion cohort (n=25) experienced grade 3 ADRs. The most common ADRs were hair color changes, fatigue, portal hypertension, hypertriglyceridemia, and proteinuria. During dose expansion, the patients treated with 200 mg and 100 mg (once daily) showed an objective response rate of 22.2% and 5.9%, respectively; the disease control rate was 88.9% and 73.3%, respectively; the median PFS was 9.9 [95% confidence interval (95% CI): 7.4-not reached] months and 3.8 (95% CI: 1.9-not reached) months, respectively. CONCLUSIONS: Oral vorolanib at a dose of 200 mg (once daily) exhibited an acceptable safety profile and favorable clinical benefit for patients with advanced solid tumors. The RP2D for vorolanib was determined to be 200 mg as a daily regimen.

Vorolanib (X-82), an oral anti-VEGFR/PDGFR/CSF1R tyrosine kinase inhibitor, with everolimus in solid tumors: results of a phase I study.

Background Anti-vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitors (TKI) combined with mTOR inhibitors, like everolimus, result in significant responses and prolonged progression-free survival (PFS) among patients with renal cell carcinoma (RCC) [1]. However, everolimus doses >5 mg are often not tolerated when combined with other TKIs2,3. Vorolanib (X-82), an oral anti-VEGFR/platelet derived growth factor receptor (PDGFR)/colony stimulating factor 1 receptor (CSF1R) multitarget TKI, has a short half-life and limited tissue accumulation. We conducted a Phase 1 study of vorolanib with everolimus (10 mg daily) in patients with solid tumors. Methods A 3 + 3 dose escalation design was utilized to determine dose limiting toxicities (DLT) and recommended Phase 2 dose (RP2D) of vorolanib/everolimus. Oral vorolanib at 100, 150, 200, 300, or 400 mg was combined with 10 mg oral everolimus daily. The phase 2 portion was terminated after enrolling two patients due to funding. Results Eighteen patients were evaluable for DLT among 22 treated subjects. Observed DLTs were grade 3 fatigue, hypophosphatemia, and mucositis. The RP2D is vorolanib 300 mg with everolimus 10 mg daily. In 15 patients evaluable for response, three had partial response (PR; 2 RCC, 1 neuroendocrine tumor [NET]) and eight had stable disease (SD; 2 RCC, 6 NET). Conclusions Vorolanib can safely be combined with everolimus. Encouraging activity is seen in RCC and NET. Further studies are warranted. Trial Registration Number: NCT01784861.

Monitoring Therapeutic Response and Resistance: Analysis of Circulating Tumor DNA in Patients With ALK+ Lung Cancer.

INTRODUCTION: Despite initial effectiveness of ALK receptor tyrosine kinase inhibitors (TKIs) in patients with ALK+ NSCLC, therapeutic resistance will ultimately develop. Serial tracking of genetic alterations detected in circulating tumor DNA (ctDNA) can be an informative strategy to identify response and resistance. This study evaluated the utility of analyzing ctDNA as a function of response to ensartinib, a potent second-generation ALK TKI. METHODS: Pre-treatment plasma was collected from 76 patients with ALK+ NSCLC who were ALK TKI-naive or had received prior ALK TKI, and analyzed for specific genetic alterations. Longitudinal plasma samples were analyzed from a subset (n = 11) of patients. Analysis of pre-treatment tumor biopsy specimens from 22 patients was compared with plasma. RESULTS: Disease-associated genetic alterations were detected in 74% (56 of 76) of patients, the most common being EML4-ALK. Concordance of ALK fusion between plasma and tissue was 91% (20 of 22 blood and tissue samples). Twenty-four ALK kinase domain mutations were detected in 15 patients, all had previously received an ALK TKI; G1269A was the most prevalent (4 of 24). Patients with a detectable EML4-ALK variant 1 (V1) fusion had improved response (9 of 17 patients; 53%) to ensartinib compared to patients with EML4-ALK V3 fusion (one of seven patients; 14%). Serial changes in ALK alterations were observed during therapy. CONCLUSIONS: Clinical utility of ctDNA was shown, both at pre-treatment by identifying a potential subgroup of ALK+ NSCLC patients who may derive more benefit from ensartinib and longitudinally by tracking resistance. Prospective application of this technology may translate to improved outcomes for NSCLC patients treated with ALK TKIs.

Phase I, First-in-Human, Dose-Escalation Study to Evaluate the Safety, Tolerability, and Pharmacokinetics of Vorolanib in Patients with Advanced Solid Tumors.

LESSONS LEARNED: Pharmacokinetic results underscore that the vorolanib (X-82) study design was successful without the need for further dose escalation beyond 400 mg once daily (q.d.).Therefore, the recommended dose of X-82 as a single agent in patients with advanced cancer is 400 mg q.d. BACKGROUND: Vorolanib (X-82) is a novel, oral, multikinase vascular endothelial growth factor (VEGF) receptor/platelet-derived growth factor (PDGF) receptor inhibitor that was developed on the same chemical scaffold as sunitinib, but designed to improve upon the safety profile while maintaining the efficacy of sunitinib. By targeting the VEGF and PDGF receptors, X-82 was expected to disrupt tumor angiogenesis and be active in a broad spectrum of solid tumors. Therefore, we determined the maximum tolerated dose (MTD) and characterized the preliminary pharmacokinetics and clinical tumor response of X-82 as a single agent in patients with advanced solid tumors. METHODS: Adult patients with advanced solid tumors received X-82 as tablets or capsules (once daily [q.d.] or b.i.d.) every 4 weeks. Patients were evaluated for response every 8 weeks, and continued treatment until disease progression or intolerable toxicity. RESULTS: Fifty-two patients received study treatment in 17 cohorts. X-82 capsule dosing was as follows: cohorts 1-6 (20-400 mg q.d.) and cohorts 7-8 (140-200 mg b.i.d.). Patients in cohorts 9-17 received 50-800 mg q.d. tablet dosing. The median time on treatment was 58 days. X-82 blood pharmacokinetics appeared dose-independent with a t 1/2 of 5.13 hours and 6.48 hours for capsule and tablet formulations, respectively. No apparent accumulation was observed after 21 days of daily dosing. CONCLUSION: X-82 had a safety profile consistent with its mechanism of action. It has a short half-life and was well tolerated by most patients. Study enrollment ended prior to the determination of the MTD because of the apparent saturation of absorption at 400-800 mg. The recommended dose of X-82 as a single agent in patients with advanced cancer is 400 mg q.d.

Pharmacodynamic study using FLT PET/CT in advanced solid malignancies treated with a sequential combination of X-82 and docetaxel.

BACKGROUND: A sequential approach, synchronizing cell-cycle specific chemotherapy during VEGFR-TKI treatment breaks, may improve the therapeutic index of this combination therapy. In this study we investigate the safety/tolerability and pharmacodynamic effects of docetaxel used in sequential combination with the novel VEGFR-TKI X-82. METHODS: Patients with advanced solid malignancies underwent 21-day treatment cycles with X-82 administered daily on days 1-14, a treatment break on days 15-20, and docetaxel administered on day 21. Randomization was 1:1 to either a low-dose X-82 (200 mg) or high-dose X-82 (400 mg) arm. Patients were scheduled to undergo four 3'-deoxy-3'-18F-fluorothymidine (FLT) PET/CT scans to assess changes in tumor cell proliferation. PET standardized uptake values (SUV) were summarized for tumors and changes were assessed using mixed effects models. RESULTS: 14 patients were enrolled and treated with median 3.5 cycles (range 0-12). Three patients in the high-dose cohort (50%) and three patients in the low-dose cohort (38%) experienced at least one grade 3 adverse event during the study (infections, cytopenias, electrolyte abnormalities, and vascular complications). Four patients with 13 metastatic tumors underwent FLT PET/CT scanning. During the cycle 1 X-82 exposure period, tumor SUVmax decreased by - 11% (p = 0.04). After administration of docetaxel and the cycle 2 X-82 exposure period, tumor SUVmax decreased - 44% (p = 0.03). CONCLUSIONS: The sequential combination of X-82 and docetaxel was safe and led to diminished FLT uptake. Further, decrease in FLT uptake during cycle 2 (X-82 plus docetaxel) was greater than in cycle 1 (X-82 alone), suggesting sequential chemotherapy enhances the pharmacodynamic effect of therapy.

Dual PI3 K/mTOR inhibition reduces prostate cancer bone engraftment altering tumor-induced bone remodeling.

Morbidity in advanced prostate cancer patients is largely associated with bone metastatic events. The development of novel therapeutic strategies is imperative in order to effectively treat this incurable stage of the malignancy. In this context, Akt signaling pathway represents a promising therapeutic target able to counteract biochemical recurrence and metastatic progression in prostate cancer. We explored the therapeutic potential of a novel dual PI3 K/mTOR inhibitor, X480, to inhibit tumor growth and bone colonization using different in vivo prostate cancer models including the subcutaneous injection of aggressive and bone metastatic (PC3) and non-bone metastatic (22rv1) cell lines and preclinical models known to generate bone lesions. We observed that X480 both inhibited the primary growth of subcutaneous tumors generated by PC3 and 22rv1 cells and reduced bone spreading of PCb2, a high osteotropic PC3 cell derivative. In metastatic bone, X480 inhibited significantly the growth and osteolytic activity of PC3 cells as observed by intratibial injection model. X480 also increased the bone disease-free survival compared to untreated animals. In vitro experiments demonstrated that X480 was effective in counteracting osteoclastogenesis whereas it stimulated osteoblast activity. Our report provides novel information on the potential activity of PI3 K/Akt inhibitors on the formation and progression of prostate cancer bone metastases and supports a biological rationale for the use of these inhibitors in castrate-resistant prostate cancer patients at high risk of developing clinically evident bone lesions.

Ensartinib (X-396) in ALK-Positive Non-Small Cell Lung Cancer: Results from a First-in-Human Phase I/II, Multicenter Study.

Purpose: Evaluate safety and determine the recommended phase II dose (RP2D) of ensartinib (X-396), a potent anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitor (TKI), and evaluate preliminary pharmacokinetics and antitumor activity in a first-in-human, phase I/II clinical trial primarily in patients with non-small cell lung cancer (NSCLC).Patients and Methods: In dose escalation, ensartinib was administered at doses of 25 to 250 mg once daily in patients with advanced solid tumors; in dose expansion, patients with advanced ALK-positive NSCLC were administered 225 mg once daily. Patients who had received prior ALK TKI(s) and patients with brain metastases were eligible.Results: Thirty-seven patients enrolled in dose escalation, and 60 enrolled in dose expansion. The most common treatment-related toxicities were rash (56%), nausea (36%), pruritus (28%), vomiting (26%), and fatigue (22%); 23% of patients experienced a treatment-related grade 3 to 4 toxicity (primarily rash and pruritus). The maximum tolerated dose was not reached, but the RP2D was chosen as 225 mg based on the frequency of rash observed at 250 mg without improvement in activity. Among the ALK-positive efficacy evaluable patients treated at ≥200 mg, the response rate (RR) was 60%, and median progression-free survival (PFS) was 9.2 months. RR in ALK TKI-naïve patients was 80%, and median PFS was 26.2 months. In patients with prior crizotinib only, the RR was 69% and median PFS was 9.0 months. Responses were also observed in the central nervous system, with an intracranial RR of 64%.Conclusions: Ensartinib was active and generally well tolerated in patients with ALK-positive NSCLC. Clin Cancer Res; 24(12); 2771-9. ©2018 AACR.

Oral Tyrosine Kinase Inhibitor for Neovascular Age-Related Macular Degeneration: A Phase 1 Dose-Escalation Study.

Importance: An oral treatment for neovascular age-related macular degeneration would be less burdensome than repeated intravitreous injections. X-82 is an oral tyrosine kinase inhibitor active against vascular endothelial growth factor (VEGF) and platelet-derived growth factor. Objective: To undertake safety testing of oral X-82 administered for the treatment of neovascular AMD. Design, Setting, and Participants: Phase 1, open-label, uncontrolled, dose-escalation study at 5 US retinal clinics between November 2012 and March 2015 (Retina-Vitreous Associates Medical Group, Beverly Hills, California; Blanton Eye Institute, Houston Methodist Hospital, Retina Consultants of Houston, Houston, Texas; New England Retina Associates, Guilford, Connecticut; Elman Retina Group, Baltimore, Maryland; and Retina Research Institute of Texas, Abilene). Thirty-five participants with neovascular age-related macular degeneration, 7 of whom were treatment naive. Interventions: Participants received oral X-82 for 24 weeks at 50 mg alternate days (n = 3), 50 mg daily (n = 8), 100 mg alternate days (n = 4), 100 mg daily (n = 10), 200 mg daily (n = 7), and 300 mg daily (n = 3), with intravitreous anti-VEGF therapy using predefined retreatment criteria. Every 4 weeks, participants underwent best-corrected visual acuity measurement, fundus examination, and spectral-domain optical coherence tomography. Main Outcomes and Measures: The main outcome was adverse events. Other outcomes included visual acuity, central subfield retinal thickness, and number of anti-VEGF injections. Results: Of the 35 participants, the mean age was 76.8 years, 16 were men and 19 were women, and 33 were white and 2 were nonwhite. Of 25 participants (71%) who completed the 24 weeks of X-82 treatment, all except 1 maintained or improved their visual acuity (mean [SD], +3.8 [9.6] letters). Fifteen participants (60%) required no anti-VEGF injections (mean, 0.68). Mean [SD] central subfield thickness reduced by -50 [97] µm, with 8 participants (all receiving at least 100 mg daily) demonstrating sustained reductions despite no anti-VEGF injections. The most common adverse events attributed to X-82 were diarrhea (n = 6), nausea (n = 5), fatigue (n = 5), and transaminase elevation (n = 4). A dose relationship to the transaminase elevations was not identified; all normalized when X-82 was discontinued. All but 1 were asymptomatic. Ten participants withdrew consent or discontinued prematurely, 6 owing to adverse events attributed to X-82 including leg cramps (n = 2), elevated alanine aminotransferase (n = 2), diarrhea (n = 1), and nausea/anorexia (n = 1). Conclusions and Relevance: X-82 can be associated with reversible, elevated liver enzymes; hence, liver function testing is needed to identify those unsuited to treatment. Although 17% of participants discontinued X-82 owing to AEs, those who completed the study had lower than expected anti-VEGF injection rates. Further studies appear justified, with a phase 2 randomized clinical study under way.

New therapeutic strategies in neuroblastoma: combined targeting of a novel tyrosine kinase inhibitor and liposomal siRNAs against ALK.

Many different aberrations in the Anaplastic Lymphoma Kinase (ALK) were found to be oncogenic drivers in several cancers including neuroblastoma (NB), therefore ALK is now considered a critical player in NB oncogenesis and a promising therapeutic target. The ALK-inhibitor crizotinib has a limited activity against the various ALK mutations identified in NB patients. We tested: the activity of the novel ALK-inhibitor X-396 administered alone or in combination with Targeted Liposomes carrying ALK-siRNAs (TL[ALK-siRNA]) that are active irrespective of ALK gene mutational status; the pharmacokinetic profiles and the biodistribution of X-396; the efficacy of X-396 versus crizotinib treatment in NB xenografts; whether the combination of X-396 with the TL[ALK-siRNA] could promote long-term survival in NB mouse models. X-396 revealed good bioavailability, moderate half-life, high mean plasma and tumor concentrations. X-396 was more effective than crizotinib in inhibiting in vitro cell proliferation of NB cells and in reducing tumor volume in subcutaneous NB models in a dose-dependent manner. In orthotopic NB xenografts, X-396 significantly increased life span independently of the ALK mutation status. In combination studies, all effects were significantly improved in the mice treated with TL[ALK-siRNA] and X-396 compared to mice receiving the single agents. Our findings provide a rational basis to design innovative molecular-based treatment combinations for clinical application in ALK-driven NB tumors.

Upregulation of MAPK Negative Feedback Regulators and RET in Mutant ALK Neuroblastoma: Implications for Targeted Treatment.

PURPOSE: Activating ALK mutations are present in almost 10% of primary neuroblastomas and mark patients for treatment with small-molecule ALK inhibitors in clinical trials. However, recent studies have shown that multiple mechanisms drive resistance to these molecular therapies. We anticipated that detailed mapping of the oncogenic ALK-driven signaling in neuroblastoma can aid to identify potential fragile nodes as additional targets for combination therapies. EXPERIMENTAL DESIGN: To achieve this goal, transcriptome profiling was performed in neuroblastoma cell lines with the ALK(F1174L) or ALK(R1275Q) hotspot mutations, ALK amplification, or wild-type ALK following pharmacologic inhibition of ALK using four different compounds. Next, we performed cross-species genomic analyses to identify commonly transcriptionally perturbed genes in MYCN/ALK(F1174L) double transgenic versus MYCN transgenic mouse tumors as compared with the mutant ALK-driven transcriptome in human neuroblastomas. RESULTS: A 77-gene ALK signature was established and successfully validated in primary neuroblastoma samples, in a neuroblastoma cell line with ALK(F1174L) and ALK(R1275Q) regulable overexpression constructs and in other ALKomas. In addition to the previously established PI3K/AKT/mTOR, MAPK/ERK, and MYC/MYCN signaling branches, we identified that mutant ALK drives a strong upregulation of MAPK negative feedback regulators and upregulates RET and RET-driven sympathetic neuronal markers of the cholinergic lineage. CONCLUSIONS: We provide important novel insights into the transcriptional consequences and the complexity of mutant ALK signaling in this aggressive pediatric tumor. The negative feedback loop of MAPK pathway inhibitors may affect novel ALK inhibition therapies, whereas mutant ALK induced RET signaling can offer novel opportunities for testing ALK-RET oriented molecular combination therapies.

Simultaneous targeting of PI3Kδ and a PI3Kδ-dependent MEK1/2-Erk1/2 pathway for therapy in pediatric B-cell acute lymphoblastic leukemia.

B cell acute lymphoblastic leukemia (B-ALL) is the most common hematological malignancy diagnosed in children, and blockade of the abnormally activated PI3Kδ displayed promising outcomes in B cell acute or chronic leukemias, but the mechanisms are not well understood. Here we report a novel PI3Kδ selective inhibitor X-370, which displays distinct binding mode with p110δ and blocks constitutively active or stimulus-induced PI3Kδ signaling. X-370 significantly inhibited survival of human B cell leukemia cells in vitro, with associated induction of G1 phase arrest and apoptosis. X-370 abrogated both Akt and Erk1/2 signaling via blockade of PDK1 binding to and/or phosphorylation of MEK1/2. Forced expression of a constitutively active MEK1 attenuated the antiproliferative activity of X-370. X-370 preferentially inhibited the survival of primary pediatric B-ALL cells displaying PI3Kδ-dependent Erk1/2 phosphorylation, while combined inhibition of PI3Kδ and MEK1/2 displayed enhanced activity. We conclude that PI3Kδ inhibition led to abrogation of both Akt and Erk1/2 signaling via a novel PI3K-PDK1/MEK1/2-Erk1/2 signaling cascade, which contributed to its efficacy against B-ALL. These findings support the rationale for clinical testing of PI3Kδ inhibitors in pediatric B-ALL and provide insights needed to optimize the therapeutic strategy.

A novel lead compound CM-118: antitumor activity and new insight into the molecular mechanism and combination therapy strategy in c-Met- and ALK-dependent cancers.

The anaplastic lymphoma kinase (ALK) and the c-Met receptor tyrosine kinase play essential roles in the pathogenesis in multiple human cancers and present emerging targets for cancer treatment. Here, we describe CM-118, a novel lead compound displaying low nanomolar biochemical potency against both ALK and c-Met with selectivity over>90 human kinases. CM-118 potently abrogated hepatocyte growth factor (HGF)-induced c-Met phosphorylation and cell migration, phosphorylation of ALK, EML4-ALK, and ALK resistance mutants in transfected cells. CM-118 inhibited proliferation and/or induced apoptosis in multiple c-Met- and ALK-addicted cancer lines with dose response profile correlating target blockade. We show that the CM-118-induced apoptosis in c-Met-amplified H1993 NSCLC cells involved a rapid suppression of c-Met activity and c-Met-to-EGFR cross-talk, and was profoundly potentiated by EGFR inhibitors as shown by the increased levels of apoptotic proteins cleaved-PARP and Bim as well as reduction of the survival protein Mcl-1. Bim-knockdown or Mcl-1 overexpression each significantly attenuated apoptosis. We also revealed a key role by mTOR in mediating CM-118 action against the EML4-ALK-dependent NSCLC cells. Abrogation of EML4-ALK in H2228 cells profoundly reduced signaling capacity of the rapamycin-sensitive mTOR pathway leading to G 1 cell cycle arrest and mitochondrial hyperpolarization, a metabolic perturbation linked to mTOR inhibition. Depletion of mTOR or mTORC1 inhibited H2228 cell growth, and mTOR inhibitors potentiated CM-118's antitumor activity in vitro and in vivo. Oral administration of CM-118 at a wide range of well tolerated dosages diminished c-Met- and ALK phosphorylation in vivo, and caused tumor regression or growth inhibition in multiple c-Met- and ALK-dependent tumor xenografts in mice. CM-118 exhibits favorable pharmacokinetic and drug metabolism properties hence presents a candidate for clinical evaluation.

Inhibition of tumor cell growth, proliferation and migration by X-387, a novel active-site inhibitor of mTOR.

The mammalian target of rapamycin (mTOR), is deregulated in about 50% of human malignancies and exists in two complexes: mTORC1 and mTORC2. Rapalogs partially inhibit mTORC1 through allosteric binding to mTORC1 and their efficacy is modest as a cancer therapy. A few mTOR kinase inhibitors that inhibit both mTORC1 and mTORC2 have been reported to possess potent anticancer activities. Herein, we designed and synthesized a series of pyrazolopyrimidine derivatives targeting mTOR kinase domain and X-387 was identified as a promising lead. X-387 selectively inhibited mTOR in an ATP-competitive manner while sparing a panel of kinases from the PIKK family. X-387 blocked mTORC1 and mTORC2-mediacted signaling pathway in cell lines with activated mTOR signaling and in rapamycin-resistant cells. Specifically, X-387 inhibited phosphorylation of AKT at T308, which is thought to be a target of PDK1 but not mTOR. Such activity was not due to inhibition of PI3K since X-387 did not inhibit translocation of AKT to the cell membrane. X-387 induced autophagy as observed for other mTOR inhibitors, while induced autophagy is pro-survival since concurrent inhibition of autophagy by 3-MA reinforced the antiproliferative activity of mTOR inhibitors. X-387 also inhibited cell motility, which is associated with decrease in activity of small GTPases such as RhoA, Rac1 and Cdc42. Taken together, X-387 is a promising compound lead targeting mTOR and with a wide spectrum anticancer activity among tumor cell lines. The data also underscores the complexity of the mTOR signaling pathways which are far from being understood.

Insights into ALK-driven cancers revealed through development of novel ALK tyrosine kinase inhibitors.

Aberrant forms of the anaplastic lymphoma kinase (ALK) have been implicated in the pathogenesis of multiple human cancers, where ALK represents a rational therapeutic target in these settings. In this study, we report the identification and biological characterization of X-376 and X-396, two potent and highly specific ALK small molecule tyrosine kinase inhibitors (TKIs). In Ambit kinome screens, cell growth inhibition studies, and surrogate kinase assays, X-376 and X-396 were more potent inhibitors of ALK but less potent inhibitors of MET compared to PF-02341066 (PF-1066), an ALK/MET dual TKI currently in clinical trials. Both X-376 and X-396 displayed potent antitumor activity in vivo with favorable pharmacokinetic and toxicity profiles. Similar levels of drug sensitivity were displayed by the three most common ALK fusion proteins in lung cancer (EML4-ALK variants E13;A20, E20;A20, and E6b;A20) as well as a KIF5B-ALK fusion protein. Moreover, X-396 could potently inhibit ALK kinases engineered with two point mutations associated with acquired resistance to PF-1066, L1196M, and C1156Y, when engineered into an E13;A20 fusion variant. Finally, X-396 displayed synergistic growth inhibitory activity when combined with the mTOR inhibitor rapamycin. Our findings offer preclinical proof-of-concept for use of these novel agents to improve therapeutic outcomes of patients with mutant ALK-driven malignancies.

SU14813: a novel multiple receptor tyrosine kinase inhibitor with potent antiangiogenic and antitumor activity.

Receptor tyrosine kinases (RTK), such as vascular endothelial growth factor receptor (VEGFR), platelet-derived growth factor receptor (PDGFR), stem cell factor receptor (KIT), and fms-like tyrosine kinase 3 (FLT3), are expressed in malignant tissues and act in concert, playing diverse and major roles in angiogenesis, tumor growth, and metastasis. With the exception of a few malignancies, seemingly driven by a single genetic mutation in a signaling protein, most tumors are the product of multiple mutations in multiple aberrant signaling pathways. Consequently, simultaneous targeted inhibition of multiple signaling pathways could be more effective than inhibiting a single pathway in cancer therapies. Such a multitargeted strategy has recently been validated in a number of preclinical and clinical studies using RTK inhibitors with broad target selectivity. SU14813, a small molecule identified from the same chemical library used to isolate sunitinib, has broad-spectrum RTK inhibitory activity through binding to and inhibition of VEGFR, PDGFR, KIT, and FLT3. In cellular assays, SU14813 inhibited ligand-dependent and ligand-independent proliferation, migration, and survival of endothelial cells and/or tumor cells expressing these targets. SU14813 inhibited VEGFR-2, PDGFR-beta, and FLT3 phosphorylation in xenograft tumors in a dose- and time-dependent fashion. The plasma concentration required for in vivo target inhibition was estimated to be 100 to 200 ng/mL. Used as monotherapy, SU14813 exhibited broad and potent antitumor activity resulting in regression, growth arrest, or substantially reduced growth of various established xenografts derived from human or rat tumor cell lines. Treatment in combination with docetaxel significantly enhanced both the inhibition of primary tumor growth and the survival of the tumor-bearing mice compared with administration of either agent alone. In summary, SU14813 inhibited target RTK activity in vivo in association with reduction in angiogenesis, target RTK-mediated proliferation, and survival of tumor cells, leading to broad and potent antitumor efficacy. These data support the ongoing phase I clinical evaluation of SU14813 in advanced malignancies.

Design and synthesis of aminopropyl tetrahydroindole-based indolin-2-ones as selective and potent inhibitors of Src and Yes tyrosine kinase.

A novel series of substituted 3-[3-(aminopropyl)-4,5,6,7-tetrahydro-1H-indol-2-ylmethylene]-1,3-dihydro-indole-2-ones was discovered as potent inhibitors of the non-receptor tyrosine kinase Src and Yes. A structure-activity relationship was developed in order to optimize their potency and selectivity. Syntheses of these compounds are also described herein.