A phase I study of HM781-36B, a novel pan-HER inhibitor, in patients (pts) with advanced solid tumors.

3076 Background: HM781-36B is a pan-HER tyrosine kinase inhibitor, which showed a potent activity against the gefitinib- or erlotinib-resistant, EGFR L858R/T790M double mutant cells. A phase I study was conducted to determine the MTD, pharmacokinetics, and antitumor activity. Methods: Eligible pts had advanced malignancies refractory to standard therapies. Standard 3+3 scheme was used in the dose escalation part, and additional 12 pts were enrolled in the expansion cohort of molecular enrichment. Results: In dose-escalation part, 43 pts (median age: 55 yrs (range 25-82), M:F=25:18, ECOG PS 0/1/2/3: 23/17/2/1, median prior chemotherapy: 4) were treated. DLTs were G3 diarrheas in 5 pts, one at 12 mg, 16 mg, 24 mg, and two at 32 mg. The MTD was determined as 24mg. The most common drug-related adverse events were diarrhea, stomatitis, rash, pruritus, and anorexia. Among 41 evaluable pts, 4 pts achieved PR (1 unconfirmed, duration of response: 11.9 mo, 7.07 mo+, 4.5 mo+), and 19 pts had SD. Two of 4 PR pts wer...