Tan, Eng Huat

e17017 Background: Epigenetic up-regulation of EBV and cellular genes via demethylation and histone deacetylase inhibition can induce EBV lytic replication enhancing immune mediated tumor killing and up-regulation of tumor suppressor genes resulting in tumor apoptosis. Methods: Patients (Pt) with relapsed or refractory NPC and NK-T cell lymphomas were enrolled to determine safety, tolerability, pharmacokinetics (PK), pharmacodynamics and preliminary anti-tumor activity using a dose escalation design. 5AC was administered on days 1 to 10 sub-cutaneously while SAHA was administered on days 1 to 14 orally. PK for SAHA, EBV viral load, characterization of circulating EBV, Immunohistochemistry (IHC) and EBV promoter methylation analysis in tumor tissue were performed. Results: 11 pt have been treated (M:F 8:3, median age 48, R: 35-71) at 3 dose levels – 5AC 50 mg/m2 and SAHA 200 mg b.i.d. (dose level 1), 5AC 37.5 mg/m2 and SAHA 200 mg q. am and 100 mg q. pm (dose level 2), and 5AC 25 mg/m2 and SAHA 100 mg b.i.d (dose level 3). Median number of previous treatment regimens was 3 (R:1-6). Dose limiting toxicities (DLT) were seen in 2/2 pts at dose level 1: grade 4 thrombocytopenia (1 pt), grade 3 nausea, vomiting and fatigue (2 pts), and grade 5 hepatic failure (1 pt). Two of six patients at dose level 2 experienced DLT: grade 3 fatigue (1 pt) and worsening of pre-existing Sweet’s Syndrome (1 pt). Common AEs (G1/2) included fatigue (73%), cough (64%), anorexia (55%), and injection site reaction (45%). One minor response was seen and 5 pt had prolonged stable disease (>16 weeks), including one patient for 88 weeks. Analysis of post-treatment tumor biopsies showed demethylation of EBV lytic cycle gene promoters after treatment. SAHA PK, IHC results for EBV gene expression in tumor tissue, EBV viral load and characterization of circulating EBV will be presented. Conclusions: 5AC/SAHA appears to be tolerable at dose level 3 with suggestion of clinical benefit. Analysis of post-treatment tumor and blood samples suggests that modulation of EBV gene expression may play a role in the mechanism underlying clinical benefit. Continued accrual at dose level 3 is ongoing. Clinical trial information: NCT00336063.

Abstract Background: NPC is endemic to Asia and over 40% of cases harbor PIK3CA amplification. MK2206 is an allosteric AKT inhibitor with activity in NPC in vitro. Methods: Pts who had progressed after palliative chemotherapy (chemo) for metastatic or recurrent NPC, received oral MK-2206 at 200 mg on Days 1, 8, 15 & 22 of each 28-day cycle until disease progression. Plasma samples were collected at serial time points during cycle 1 for EBV DNA analysis, archived tumor samples were collected where feasible. The primary dual endpoints (2-stage design) consisted of RECIST-defined tumor response rate (RR) and 6-month (m) progression-free survival (PFS) rate. Secondary endpoints were overall survival (OS), PFS and adverse events (AEs). Results: Of the 21 pts enrolled, the median age was 47 years (range: 32-67), 91% were male, 81% had prior radiotherapy and 81% had > 1 prior line of palliative chemo. At the time of analysis, 20 out of 21 pts have ended treatment. The best responses were: 1 partial response (PR, 5%) lasting 4 ms; 10 stable disease (SD, 50%), 9 progressive disease (PD, 45%). The 6-m PFS rate was 38.9% (95% CI: 18.1-59.3%) and median PFS was 2.7 ms (95% CI: 0.9-7.2 ms). The 6-m OS rate was 67.9% (95% CI: 41.8-84.1%) and median survival has not been reached. In 7 pts who had SD more than or equal to 6 ms, the duration of treatment ranged from 6.4-13.9 ms. Of the 21 pts evaluable for AEs, 12 pts (57%) had at least one grade 3 AE [[Unable to Display Character: –]] macular rash (6 pts - 29%), dysphagia (2 pts - 10%), hyperglycemia (2 pts - 10%) (see Table 1). The tumor samples of 7 pts were analyzed by FISH; 3 showed PIK3CA amplification, including 1 pt with chromosome 3 polysomy. Amongst these pts, 1 had SD more than 6ms, 1 had SD more than 12 ms, and 1 is still on treatment. Pts who had SD less than 6 m or PD did not have PIK3CA amplification. Conclusions: MK2206 is well tolerated and has signs of activity in unselected pts with NPC. Preliminary results suggest that PIK3CA amplification may be related to prolonged disease stabilization from MK2206, and analysis for other PIK3CA gene alterations in more samples will be undertaken. Result of the plasma EBV DNA result will be presented. Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B273. Citation Format: Brigette B. Ma, Boon Cher Goh, Wan Teck Lim, Eng Huat Tan, Gilberto de Lima Lopes, Edwin P. Hui, Ann D. King, Kwok Wai Lo, Herbert Loong, Leung Li, Nathan Foster, Michael Kam, Sing Fai Leung, Charles Erlichman, Anthony TC Chan. Multicenter Phase II study of MK-2206 in previously treated patients (pts) with recurrent and metastatic nasopharyngeal carcinoma (NPC): Mayo Clinic Phase II Consortium (Protocol: MC1079). [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B273.