A phase I/Ib study of trametinib (GSK1120212) alone and in combination with gemcitabine in Japanese patients with advanced solid tumors.

BACKGROUND: Trametinib is an inhibitor of MEK1/MEK2 activation and kinase activity. In order to evaluate the safety, tolerability, pharmacokinetics, and preliminary efficacy of single-agent trametinib (part 1) and trametinib in combination with gemcitabine (part 2), we undertook the first clinical study of this combination in Japanese patients with cancer and herein report our results. METHODS: In part 1, 13 patients with advanced solid tumors were enrolled into 3 dose cohorts, receiving trametinib once daily at a dose of 1.0, 2.0, or 3.0 mg. In part 2, 5 patients with pancreatic cancer received trametinib (2.0 mg once daily) in combination with gemcitabine (1000 mg/m(2)). RESULTS: In part 1, a dose-limiting toxicity was observed in a patient in the 2.0-mg dose cohort, but the maximum tolerated dose was not reached at doses up to 3.0 mg daily. The best overall response was a PR in 1 patient, and 6 patients had SD. In part 2, the combination of trametinib and gemcitabine was tolerated for a short period of time. However, serious interstitial lung disease (ILD) was observed in 3 of 5 patients 4 weeks or more after the start of the treatment, including 1 fatal case. Three patients achieved a PR, and 2 patients had SD. The most common adverse event was rash (85 % in part 1 and 100 % in part 2). CONCLUSIONS: Trametinib monotherapy was tolerable in Japanese patients with cancer. However, the combination of trametinib plus gemcitabine carried a higher risk as compared with monotherapy, during which no ILD was observed. (ClinicalTrials.gov number, NCT01324258.).

Safety, pharmacokinetics and efficacy findings in an open-label, single-arm study of weekly paclitaxel plus lapatinib as first-line therapy for Japanese women with HER2-positive metastatic breast cancer.

BACKGROUND: Lapatinib is the human epidermal growth factor receptor 2 (HER2) targeting agent approved globally for HER2-positive metastatic breast cancer (MBC). The efficacy, safety and pharmacokinetics (PK) of lapatinib combined with paclitaxel (L+P) were investigated in this study, to establish clear evidence regarding the combination in Japanese patients. METHODS: In this two-part, single-arm, open-label study, the tolerability of L+P as first-line treatment in Japanese patients with HER2-positive MBC was evaluated in six patients in the first part, and the safety, efficacy and PK were evaluated in a further six patients (making a total of twelve patients) in the second part. Eligible women were enrolled and received lapatinib 1500 mg once daily and paclitaxel 80 mg/m(2) weekly for at least 6 cycles. RESULTS: The only dose-limiting toxicity reported was Grade 3 diarrhea in one patient. The systemic exposure to maximum plasma concentration and area under the plasma concentration curve (AUC) for lapatinib, as well as the AUC of paclitaxel, were increased when combined. The most common adverse events (AEs) related to the study treatment were alopecia, diarrhea and decreased hemoglobin. The majority of drug-related AEs were Grade 1 or 2. The median overall survival was 35.6 months (95 % confidence interval 23.9, not reached). The response rate and clinical benefit rate were both 83 % (95 % confidence interval 51.6, 97.9). CONCLUSIONS: The L+P treatment was well tolerated in Japanese patients with HER2-positive MBC. Although the PK profiles of lapatinib and paclitaxel influenced each other, the magnitudes were not greatly different from those in non-Japanese patients.

Efficacy, safety, pharmacokinetics and biomarker findings in patients with HER2-positive advanced or metastatic breast cancer treated with lapatinib in combination with capecitabine: results from 51 Japanese patients treated in a clinical study.

BACKGROUND: The results from a phase III trial conducted outside of Japan demonstrated a significant improvement in time to progression (TTP) when lapatinib was combined with capecitabine compared with capecitabine alone in patients with HER2-positive advanced or metastatic breast cancer. In this clinical study of lapatinib in combination with capecitabine, efficacy, safety, pharmacokinetics (PK) and biomarkers were investigated in Japanese patients with HER2-positive advanced or metastatic breast cancer treated with prior trastuzumab. METHODS: Eligible women received lapatinib 1250 mg once daily and capecitabine 1000 mg/m(2) twice daily on days 1 through 14 of a 21-day cycle. The primary endpoint was the clinical benefit rate (CBR: complete response, partial response or stable disease for at least 24 weeks). RESULTS: Lapatinib in combination with capecitabine was well tolerated in the 51 patients enrolled in this study. CBR was 59 % (95 % CI 44.2, 72.4), and the median TTP in the Kaplan-Meier estimate was 36 weeks (95 % CI 27.1, 48.0). The majority of drug-related adverse events were mild to moderate (grade 1 or 2); the most common adverse events reported were palmar-plantar erythrodysesthesia syndrome (76 %), diarrhea (67 %) and stomatitis (41 %). CONCLUSIONS: Lapatinib in combination with capecitabine in Japanese HER2-positive breast cancer patients was well tolerated. Overall, our findings on the efficacy, safety and PK were similar to those reported from the overseas studies.