A phase II study of dasatanib (BMS 354825) in recurrent or metastatic ckit-expressing adenoid cystic (ACC) and non-ACC malignant salivary glands tumors (MSGT).

Abstract

6022 Background: ACC is a rare disease, accounting for 1/3rd of MSGT, in which 90% of cases express the protein product of the ckit proto-oncogene. Dasatinib is a potent and selective inhibitor of five oncogenic PTKs/kinase families including ckit. We conducted a phase II study to determine the antitumor activity of dasatinib in ACC and non-ACC MSGT. Methods: In a two-stage design, adult patients (pts) with recent radiographic progressive, recurrent or metastatic ACC, + cKIT, were treated with dasatinib 70 mg PO BID. Pts with non-ACC MSGT of other histologic types, were treated as a separate cohort. Response was assessed every 8 wks by imaging using RECIST criteria. The study design stipulated enrollment of n=40 ACC patients (20 in stage I and 20 in stage II) and 25 non-ACC patients (14 in stage I and 11 in stage II). Results: Fifty-four pts were enrolled, 40 ACC and 14 non-ACC. One additional pt was a screen failure. Baseline data on 54 pts are: M:F = 28:26, median age 56.6 yrs (range 20-82), PS 0:1:2 = 24:28:2, prior radiation:chemotherapy = 44:21. The most frequent adverse events experienced (as % of pts, worst grade 2 or higher and at least possibly related to study drug) were: fatigue (28%), nausea (19%), headache (15%), lymphopenia (11%), dyspnea (11%), alanine aminotransferase increased (7%), anorexia (7%), vomiting (7%), alkaline phosphatase increased (6%), diarrhea (6%), and non-cardiac chest pain (6%). No grade 4 adverse events occurred and only 15 pts experienced a grade 3 adverse event (at least possibly attributed to study drug), primarily dyspnea (4 patients) and fatigue (3 patients). Significant cardiac toxicity was observed in one pt (grade 3 prolonged QT corrected interval). Among ACC pts, best response to dasatinib: 0 pts (0%) had PR, 21 pts (52%) had SD (range 2.8-13.8 months), 12 pts (30%) had PD, and 2 died prior to cycle 2. Median PFS was 4.8 mos. For 14 evaluable non-ACC pts, none had an objective response, triggering early stopping. 7 had SD (range 1.4-6.6 months), and 4 PD. Conclusions: Although there were no objective responses, dasatinib is well tolerated, with tumor stabilization achieved by 52% of ACC pts. Dasatinib demonstrated no activity in non-ACC MSGT. Clinical trial information: NCT00859937.