Nicola Steele

A Phase 1 Pharmacokinetic and Pharmacodynamic Study of the Histone Deacetylase Inhibitor Belinostat in Patients with Advanced Solid Tumors

Purpose: To determine the safety, dose-limiting toxicity, maximum tolerated dose, and pharmacokinetic and pharmacodynamic profiles of the novel hydroxamate histone deacetylase inhibitor belinostat (previously named PXD101) in patients with advanced refractory solid tumors. Experimental Design: Sequential dose-escalating cohorts of three to six patients received belinostat administered as a 30-min i.v. infusion on days 1 to 5 of a 21-day cycle. Pharmacokinetic variables were evaluated at all dose levels. Pharmacodynamic measurements included acetylation of histones extracted from peripheral blood mononuclear cells, caspase-dependent cleavage of cytokeratin-18, and interleukin-6 levels. Results: Forty-six patients received belinostat at one of six dose levels (150-1,200 mg/m2/d). Dose-limiting toxicities were grade 3 fatigue (one patient at 600 mg/m2; one patient at 1,200 mg/m2), grade 3 diarrhea combined with fatigue (one patient at 1,200 mg/m2), grade 3 atrial fibrillation (one patient at 1,200 mg/m2; one patient at 1,000 mg/m2), and grade 2 nausea/vomiting leading to inability to complete a full 5-day cycle (two patients at 1,000 mg/m2). The maximum tolerated dose was 1,000 mg/m2/d. I.v. belinostat displayed linear pharmacokinetics with respect to Cmax and AUC. The intermediate elimination half-life was 0.3 to 1.3 h and was independent of dose. Histone H4 hyperacetylation was observed after each infusion and was sustained for 4 to 24 h in a dose-dependent manner. Increases in interleukin-6 levels were detected following belinostat treatment. Stable disease was observed in a total of 18 (39%) patients, including 15 treated for ≥4 cycles, and this was associated with caspase-dependent cleavage of cytokeratin-18. Of the 24 patients treated at the maximum tolerated dose (1,000 mg/m2/d), 50% achieved stable disease. Conclusions: I.v. belinostat is well tolerated, exhibits dose-dependent pharmacodynamic effects, and has promising antitumor activity.

Candidate DNA methylation drivers of acquired cisplatin resistance in ovarian cancer identified by methylome and expression profiling

Multiple DNA methylation changes in the cancer methylome are associated with the acquisition of drug resistance; however it remains uncertain how many represent critical DNA methylation drivers of chemoresistance. Using isogenic, cisplatin-sensitive/resistant ovarian cancer cell lines and inducing resensitizaton with demethylating agents, we aimed to identify consistent methylation and expression changes associated with chemoresistance. Using genome-wide DNA methylation profiling across 27 578 CpG sites, we identified loci at 4092 genes becoming hypermethylated in chemoresistant A2780/cp70 compared with the parental-sensitive A2780 cell line. Hypermethylation at gene promoter regions is often associated with transcriptional silencing; however, expression of only 245 of these hypermethylated genes becomes downregulated in A2780/cp70 as measured by microarray expression profiling. Treatment of A2780/cp70 with the demethylating agent 2-deoxy-5′-azacytidine induces resensitization to cisplatin and re-expression of 41 of the downregulated genes. A total of 13/41 genes were consistently hypermethylated in further independent cisplatin-resistant A2780 cell derivatives. CpG sites at 9 of the 13 genes (ARHGDIB, ARMCX2, COL1A, FLNA, FLNC, MEST, MLH1, NTS and PSMB9) acquired methylation in ovarian tumours at relapse following chemotherapy or chemoresistant cell lines derived at the time of patient relapse. Furthermore, 5/13 genes (ARMCX2, COL1A1, MDK, MEST and MLH1) acquired methylation in drug-resistant ovarian cancer-sustaining (side population) cells. MLH1 has a direct role in conferring cisplatin sensitivity when reintroduced into cells in vitro. This combined genomics approach has identified further potential key drivers of chemoresistance whose expression is silenced by DNA methylation that should be further evaluated as clinical biomarkers of drug resistance.

Combined inhibition of DNA methylation and histone acetylation enhances gene re-expression and drug sensitivity in vivo

Histone deacetylation and DNA methylation have a central role in the control of gene expression in tumours, including transcriptional repression of tumour suppressor genes and genes involved in sensitivity to chemotherapy. Treatment of cisplatin-resistant cell lines with an inhibitor of DNA methyltransferases, 2-deoxy-5′azacytidine (decitabine), results in partial reversal of DNA methylation, re-expression of epigenetically silenced genes including hMLH1 and sensitisation to cisplatin both in vitro and in vivo. We have investigated whether the combination of decitabine and a clinically relevant inhibitor of histone deacetylase activity (belinostat, PXD101) can further increase the re-expression of genes epigenetically silenced by DNA methylation and enhance chemo-sensitisation in vivo at well-tolerated doses. The cisplatin-resistant human ovarian cell line A2780/cp70 has the hMLH1 gene methylated and is resistant to cisplatin both in vitro and when grown as a xenograft in mice. Treatment of A2780/cp70 with decitabine and belinostat results in a marked increase in expression of epigenetically silenced MLH1 and MAGE-A1 both in vitro and in vivo when compared with decitabine alone. The combination greatly enhanced the effects of decitabine alone on the cisplatin sensitivity of xenografts. As the dose of decitabine that can be given to patients and hence the maximum pharmacodynamic effect as a demethylating agent is limited by toxicity and eventual re-methylation of genes, we suggest that the combination of decitabine and belinostat could have a role in the efficacy of chemotherapy in tumours that have acquired drug resistance due to DNA methylation and gene silencing.

Management of crizotinib therapy for ALK-rearranged non-small cell lung carcinoma: An expert consensus

Within 4 years of the discovery of anaplastic lymphoma kinase (ALK) rearrangements in non-small cell lung cancer (NSCLC), the ALK inhibitor crizotinib gained US and European approval for the treatment of advanced ALK-positive NSCLC. This was due to the striking response data observed with crizotinib in phase I and II trials in patients with ALK-positive NSCLC, as well as the favorable tolerability and safety profile observed. Recently published phase III data established crizotinib as a new standard of care for this NSCLC molecular subset. A consequence of such rapid approval, however, is the limited clinical experience and relative paucity of information concerning optimal therapy management. In this review, we discuss the development of crizotinib and the clinical relevance of its safety profile, examining crizotinib-associated adverse events in detail and making specific management recommendations. Crizotinib-associated adverse events were mostly mild to moderate in severity in clinical studies, and appropriate monitoring and supportive therapies are considered effective in avoiding the need for dose interruption or reduction in most cases. Therapy management of patients following disease progression on crizotinib is also discussed. Based on available clinical data, it is evident that patients may have prolonged benefit from crizotinib after Response Evaluation Criteria in Solid Tumors-defined disease progression, and crizotinib should be continued for as long as the patient derives benefit.

Third-Line Nivolumab Monotherapy in Recurrent Small Cell Lung Cancer: CheckMate 032

Introduction: For patients with recurrent SCLC, topotecan remains the only approved second‐line treatment, and the outcomes are poor. CheckMate 032 is a phase 1/2, multicenter, open‐label study of nivolumab or nivolumab plus ipilimumab in SCLC or other advanced/metastatic solid tumors previously treated with one or more platinum‐based chemotherapies. We report results of third‐ or later‐line nivolumab monotherapy treatment in SCLC. Methods: In this analysis, patients with limited‐stage or extensive‐stage SCLC and disease progression after two or more chemotherapy regimens received nivolumab monotherapy, 3 mg/kg every 2 weeks, until disease progression or unacceptable toxicity. The primary end point was objective response rate. Secondary end points included duration of response, progression‐free survival, overall survival, and safety. Results: Between December 4, 2013, and November 30, 2016, 109 patients began receiving third‐ or later‐line nivolumab monotherapy. At a median follow‐up of 28.3 months (from first dose to database lock), the objective response rate was 11.9% (95% confidence interval: 6.5–19.5) with a median duration of response of 17.9 months (range 3.0–42.1). At 6 months, 17.2% of patients were progression‐free. The 12‐month and 18‐month overall survival rates were 28.3% and 20.0%, respectively. Grade 3 to 4 treatment‐related adverse events occurred in 11.9% of patients. Three patients (2.8%) discontinued because of treatment‐related adverse events. Conclusions: Nivolumab monotherapy provided durable responses and was well tolerated as a third‐ or later‐line treatment for recurrent SCLC. These results suggest that nivolumab monotherapy is an effective third‐ or later‐line treatment for this patient population.

Vistusertib (dual m-TORC1/2 inhibitor) in combination with paclitaxel in patients with high-grade serous ovarian and squamous non-small-cell lung cancer

Abstract Background We have previously shown that raised p-S6K levels correlate with resistance to chemotherapy in ovarian cancer. We hypothesised that inhibiting p-S6K signalling with the dual m-TORC1/2 inhibitor in patients receiving weekly paclitaxel could improve outcomes in such patients. Patients and methods In dose escalation, weekly paclitaxel (80 mg/m2) was given 6/7 weeks in combination with two intermittent schedules of vistusertib (dosing starting on the day of paclitaxel): schedule A, vistusertib dosed bd for 3 consecutive days per week (3/7 days) and schedule B, vistusertib dosed bd for 2 consecutive days per week (2/7 days). After establishing a recommended phase II dose (RP2D), expansion cohorts in high-grade serous ovarian cancer (HGSOC) and squamous non-small-cell lung cancer (sqNSCLC) were explored in 25 and 40 patients, respectively. Results The dose-escalation arms comprised 22 patients with advanced solid tumours. The dose-limiting toxicities were fatigue and mucositis in schedule A and rash in schedule B. On the basis of toxicity and pharmacokinetic (PK) and pharmacodynamic (PD) evaluations, the RP2D was established as 80 mg/m2 paclitaxel with 50 mg vistusertib bd 3/7 days for 6/7 weeks. In the HGSOC expansion, RECIST and GCIG CA125 response rates were 13/25 (52%) and 16/25 (64%), respectively, with median progression-free survival (mPFS) of 5.8 months (95% CI: 3.28–18.54). The RP2D was not well tolerated in the SqNSCLC expansion, but toxicities were manageable after the daily vistusertib dose was reduced to 25 mg bd for the following 23 patients. The RECIST response rate in this group was 8/23 (35%), and the mPFS was 5.8 months (95% CI: 2.76–21.25). Discussion In this phase I trial, we report a highly active and well-tolerated combination of vistusertib, administered as an intermittent schedule with weekly paclitaxel, in patients with HGSOC and SqNSCLC. Clinical trial registration ClinicialTrials.gov identifier: CNCT02193633