Hiroaki Itamochi

Characterization of Mutational Status, Spheroid Formation, and Drug Response of a New Genomically-Stable Human Ovarian Clear Cell Carcinoma Cell Line, 105C

Ovarian clear cell carcinoma (OCCC) is a rare subtype of gynecological cancer for which well-characterized and authenticated model systems are scarce. We provide an extensive characterization of ‘105C’, a cell line generated from an adenocarcinoma of the clear cell histotype using targeted next-generation sequencing, cytogenetic microarrays, along with analyses of AKT/mTOR signaling. We report that that the 105C cell line is a bona fide OCCC cell line, carrying PIK3CA, PTEN, and ARID1A gene mutations, consistent with OCCC, yet maintain a stable genome as reflected by low copy number variation. Unlike KOC-7c, TOV-21G, and RMG-V OCCC lines also mutated for the above genes, the 105C cells do not carry mutations in mismatch repair genes. Importantly, we show that 105C cells exhibit greater resistance to mTOR inhibition and carboplatin treatment compared to 9 other OCCC cell lines in 3D spheroid cultures. This resistance may be attributed to 105C cells remaining dormant in suspension culture which surprisingly, contrasts with several other OCCC lines which continue to proliferate in long-term suspension culture. 105C cells survive xenotransplantation but do not proliferate and metastasize. Collectively, we show that the 105C OCCC cell line exhibits unique properties useful for the pre-clinical investigation of OCCC pathobiology.

Pembrolizumab plus chemotherapy in Japanese patients with persistent, recurrent or metastatic cervical cancer: Results from KEYNOTE‐826

AbstractPembrolizumab plus chemotherapy with or without bevacizumab demonstrated prolonged progression‐free survival (PFS) and overall survival (OS) versus chemotherapy in patients with persistent, recurrent, or metastatic cervical cancer in the phase 3, randomized, double‐blind, placebo‐controlled KEYNOTE‐826 study. We report outcomes in patients enrolled in Japan. Patients received pembrolizumab 200 mg or placebo Q3W for up to 35 cycles plus chemotherapy (paclitaxel 175 mg/m2 + cisplatin 50 mg/m2 or carboplatin AUC 5) with or without bevacizumab 15 mg/kg. Dual primary endpoints were PFS per RECIST v1.1 by investigator assessment and OS in the global population; these were evaluated in patients with tumors with PD‐L1 combined positive score (CPS) ≥1, all‐comers, and PD‐L1 CPS ≥10. Fifty‐seven patients from Japan were randomized (pembrolizumab plus chemotherapy, n = 35; placebo plus chemotherapy, n = 22). Pembrolizumab plus chemotherapy improved PFS versus placebo plus chemotherapy in patients with PD‐L1 CPS ≥1 (n = 51; hazard ratio [HR; 95% CI], 0.36 [0.16–0.77]), all‐comers (n = 57; 0.45 [0.22–0.90]), and patients with PD‐L1 CPS ≥10 (n = 25; 0.36 [0.12–1.07]). HRs (95% CI) for OS were 0.38 (0.14–1.01), 0.41 (0.17–1.00), and 0.37 (0.10–1.30), respectively. Incidence of grade 3–5 AEs was 94% in the pembrolizumab group and 100% in the placebo group. Consistent with findings in the global KEYNOTE‐826 study, pembrolizumab plus chemotherapy with or without bevacizumab may prolong survival versus placebo plus chemotherapy with or without bevacizumab and had a manageable safety profile in Japanese patients with persistent, recurrent, or metastatic cervical cancer.

Niraparib in Japanese patients with platinum-sensitive recurrent ovarian cancer: final results of a multicenter phase 2 study

This study evaluated the long-term safety and efficacy of niraparib in Japanese patients with platinum-sensitive recurrent ovarian cancer. This was a follow-up analysis of a phase 2, multicenter, open-label, single-arm study in Japanese women with platinum-sensitive, relapsed ovarian cancer. Participants received niraparib (starting dose 300 mg) once daily in continuous 28-day cycles. The primary endpoint was the incidence of Grade 3 or 4 thrombocytopenia-related events (defined as the overall incidence of the MedDRA Preferred Terms "thrombocytopenia" and "platelet count decreased") occurring in the 30 days after initial administration of niraparib, and secondary endpoints included evaluation of treatment-emergent adverse events and progression-free survival. Nineteen patients (median age, 62 years; median body weight, 53.9 kg) were enrolled. As previously reported, the incidence of Grade 3 or 4 thrombocytopenia-related events during the first 30 days of treatment was 31.6%. At data cutoff, median (range) treatment exposure was 504.0 (56-1,054) days and mean ± standard deviation dose intensity was 154.4±77.5 mg/day. The most common treatment-emergent adverse events were nausea (n=14, 73.7%), decreased platelet count (n=12, 63.2%), decreased neutrophil count (n=11, 57.9%), anemia, vomiting, and decreased appetite (all n=9, 47.4%). One patient was diagnosed with treatment-related leukemia, which resulted in death. Median (95% confidence interval) progression-free survival was 18.0 (5.6-26.7) months. Overall, the safety profile of niraparib was considered manageable in this study population of Japanese patients with platinum-sensitive, relapsed ovarian cancer and was consistent with that observed in studies of non-Japanese patients. ClinicalTrials.gov Identifier: NCT03759587.