Phase Ib study of dovitinib in combination with gemcitabine plus cisplatin or gemcitabine plus carboplatin in patients with advanced solid tumors.

PURPOSE: Dovitinib is a small molecule kinase inhibitor with activity against the fibroblast growth factor and vascular endothelial growth factor receptor families. The purpose of this phase Ib study was to define the recommended phase 2 dose of the combinations of gemcitabine and cisplatin or gemcitabine and carboplatin plus dovitinib. METHODS: Patients with advanced solid tumors were enrolled in two parallel dose escalation arms (cisplatin- or carboplatin-based regimens). Treatment was administered with gemcitabine (1,000 mg/m(2) on days 1 and 8), cisplatin (70 mg/m(2)), or carboplatin (AUC 5) on day 1, and dovitinib (orally on days 1-5, 8-12, and 15-19), every 21 days. The starting dose of dovitinib was 300 mg and was dose escalated in successive cohorts using 3 + 3 dose escalation rules. RESULTS: Fourteen patients with advanced solid tumors were enrolled, five to the cisplatin arm and nine to the carboplatin arm. Patients enrolled in the cisplatin arm received a median of two cycles of treatment (range 1-5), and patients enrolled in the carboplatin arm received a median of one cycle of treatment (range 1-4). There were no protocol-defined dose-limiting toxicities in the cisplatin arm. However, the cohort was closed due to the need for frequent dose delays and/or reductions and two patients experiencing severe thromboembolic events. There were two dose-limiting toxicities in the carboplatin arm at the starting dose level of dovitinib (both prolonged neutropenia), and the dose of dovitinib was de-escalated to 200 mg. Two additional dose-limiting toxicities (prolonged neutropenia and febrile neutropenia) occurred in the lower dose cohort, and the study was closed. No patients achieved an objective response to treatment. CONCLUSIONS: Dovitinib in combination with gemcitabine plus cisplatin or gemcitabine plus carboplatin was poorly tolerated due to myelosuppression.

Phase Ib/II trial of gemcitabine, cisplatin, and lenalidomide as first-line therapy in patients with metastatic urothelial carcinoma.

BACKGROUND: Outcomes with current chemotherapy in metastatic urothelial carcinoma (MUC) remain poor. Lenalidomide, an antiangiogenic and immunomodulatory agent, enhances the effects of chemotherapy in preclinical studies. In this phase Ib/II study, we sought to determine a tolerable dose of lenalidomide in combination with gemcitabine and cisplatin (GCL) in patients with MUC and to explore the safety and activity of this regimen. METHODS: Patients with chemotherapy-naïve MUC received gemcitabine 1,000 mg/m(2) on days 1 and 8 and cisplatin 70 mg/m(2) on day 1 every 21 days. In phase Ib, there were four planned escalating dose levels of lenalidomide (10, 15, 20, and 25 mg) daily on days 1-14. RESULTS: Seven patients received GCL in phase Ib. The dose of lenalidomide was not escalated beyond 10 mg because of cytopenias requiring repeated dose delays and reductions. Two additional patients were enrolled in phase II, but the study was ultimately terminated due to poor tolerability and slow accrual. The most frequent grade ≥ 3 adverse events were cytopenias and diarrhea. Three of the nine patients experienced an objective response (one complete response, two partial responses). CONCLUSION: Chronic administration of the GCL regimen was poorly tolerated because of additive and cumulative myelosuppression.

Characterization of a novel CRAC inhibitor that potently blocks human T cell activation and effector functions.

Store operated calcium entry (SOCE) downstream of T cell receptor (TCR) activation in T lymphocytes has been shown to be mediated mainly through the Calcium Release Activated Calcium (CRAC) channel. Here, we compared the effects of a novel, potent and selective CRAC current inhibitor, 2,6-Difluoro-N-{5-[4-methyl-1-(5-methyl-thiazol-2-yl)-1,2,5,6-tetrahydro-pyridin-3-yl]-pyrazin-2-yl}-benzamide (RO2959), on T cell effector functions with that of a previously reported CRAC channel inhibitor, YM-58483, and a calcineurin inhibitor Cyclosporin A (CsA). Using both electrophysiological and calcium-based fluorescence measurements, we showed that RO2959 is a potent SOCE inhibitor that blocked an IP3-dependent current in CRAC-expressing RBL-2H3 cells and CHO cells stably expressing human Orai1 and Stim1, as well as SOCE in human primary CD4(+) T cells triggered by either TCR stimulation or thapsigargin treatment. Furthermore, we demonstrated that RO2959 completely inhibited cytokine production as well as T cell proliferation mediated by TCR stimulation or MLR (mixed lymphocyte reaction). Lastly, we showed by gene expression array analysis that RO2959 potently blocked TCR triggered gene expression and T cell functional pathways similar to CsA and another calcineurin inhibitor FK506. Thus, both from a functional and transcriptional level, our data provide evidence that RO2959 is a novel and selective CRAC current inhibitor that potently inhibits human T cell functions.

AF-353, a novel, potent and orally bioavailable P2X3/P2X2/3 receptor antagonist.

BACKGROUND AND PURPOSE: Purinoceptors containing the P2X3 subunit (P2X3 homotrimeric and P2X2/3 heterotrimeric) are members of the P2X family of ion channels gated by ATP and may participate in primary afferent sensitization in a variety of pain-related diseases. The current work describes the in vitro pharmacological characteristics of AF-353, a novel, orally bioavailable, highly potent and selective P2X3/P2X2/3 receptor antagonist. EXPERIMENTAL APPROACH: The antagonistic potencies (pIC(50)) of AF-353 for rat and human P2X3 and human P2X2/3 receptors were determined using methods of radioligand binding, intracellular calcium flux and whole cell voltage-clamp electrophysiology. KEY RESULTS: The pIC(50) estimates for these receptors ranged from 7.3 to 8.5, while concentrations 300-fold higher had little or no effect on other P2X channels or on an assortment of receptors, enzymes and transporter proteins. In contrast to A-317491 and TNP-ATP, competition binding and intracellular calcium flux experiments suggested that AF-353 inhibits activation by ATP in a non-competitive fashion. Favourable pharmacokinetic parameters were observed in rat, with good oral bioavailability (%F = 32.9), reasonable half-life (t(1/2) = 1.63 h) and plasma-free fraction (98.2% protein bound). CONCLUSIONS AND IMPLICATIONS: The combination of a favourable pharmacokinetic profile with the antagonist potency and selectivity for P2X3 and P2X2/3 receptors suggests that AF-353 is an excellent in vivo tool compound for study of these channels in animal models and demonstrates the feasibility of identifying and optimizing molecules into potential clinical candidates, and, ultimately, into a novel class of therapeutics for the treatment of pain-related disorders.