Purpose: Epithelial tumors, including non–small cell lung cancer (NSCLC) and head and neck squamous cell carcinoma (HNSCC), present clinical challenges. One potential target for systemic therapy is Src family nonreceptor tyrosine kinases, which are overexpressed in these tumors and induce pleiotropic effects, including increased proliferation, enhanced survival, stimulation of angiogenesis, and changes in motility. Dasatinib (BMS-354825), an ATP-competitive, small molecule tyrosine kinase inhibitor, suppresses the activity of these kinases at subnanomolar concentrations. Therefore, we tested the antitumor effects of this inhibitor in vitro to determine whether in vivo analyses were warranted.

Purpose: In locoregionally advanced, resectable cutaneous squamous cell carcinoma of the head and neck (CSCC-HN), surgery followed by radiotherapy is standard but can be cosmetically and functionally devastating, and many patients will have recurrence. Patients and Methods: Newly diagnosed or recurrent stage III–IVA CSCC-HN patients amenable to curative-intent surgery received two cycles of neoadjuvant PD-1 inhibition. The primary endpoint was ORR per RECIST 1.1. Secondary endpoints included pathologic response [pathologic complete response (pCR) or major pathologic response (MPR; ≤10% viable tumor)], safety, DSS, DFS, and OS. Exploratory endpoints included immune biomarkers of response. Results: Of 20 patients enrolled, 7 had recurrent disease. While only 6 patients [30%; 95% confidence interval (CI), 11.9–54.3] had partial responses by RECIST, 14 patients (70%; 95% CI, 45.7–88.1) had a pCR (n = 11) or MPR (n = 3). No SAEs ocurred during or after the neoadjuvant treatment. At a median follow-up of 22.6 months (95% CI, 21.7–26.1), one patient progressed and died, one died without disease, and two developed recurrence. The 12-month DSS, DFS, and OS rates were 95% (95% CI, 85.9–100), 89.5% (95% CI, 76.7–100), and 95% (95% CI, 85.9–100), respectively. Gene expression studies revealed an inflamed tumor microenvironment in patients with pCR or MPR, and CyTOF analyses demonstrated a memory CD8+ T-cell cluster enriched in patients with pCR. Conclusions: Neoadjuvant immunotherapy in locoregionally advanced, resectable CSCC-HN is safe and induces a high pathologic response rate. Pathologic responses were associated with an inflamed tumor microenvironment.

Purpose: Src family kinases (SFKs) promote cancer progression and are commonly expressed in non–small-cell lung cancer (NSCLC), but the clinical effects of SFK inhibition in NSCLC are unknown. We conducted a phase II trial of the SFK inhibitor dasatinib for advanced NSCLC. We tested the hypotheses that the activation of epidermal growth factor receptor (EGFR) or SFK or modulation of serum cytokines may predict a response to dasatinib. Patients and Methods: Patients received dasatinib as first-line therapy. Response was measured by tumor size on computed tomography scans and by metabolic activity on positron emission tomography scans. Tissue samples taken before patients received dasatinib were tested for EGFR and Kras mutation and phosphorylated SFK expression. Results: Thirty-four patients were enrolled. The overall disease control rate (partial responses plus stable disease) for dasatinib was 43%. One patient had a partial response to therapy. Eleven patients (32%) had a metabolic response to dasatinib. SFK activation and EGFR and Kras mutations in tumor tissue did not predict response to dasatinib. Significant toxicities included fatigue and dyspnea. The presence of a pleural effusion before dasatanib therapy predicted the development of a clinically significant effusion during therapy. Conclusion: Dasatinib as a single agent had modest clinical activity that was lower than that generally observed in patients with NSCLC who receive chemotherapy. Pleural effusion was an expected and problematic toxicity that was successfully treated with steroids, diuretics, and dose interruptions. Marked activity in one patient and prolonged stable disease in four others suggested a potential subpopulation of patients with dasatinib-sensitive NSCLC.

Purpose: In oropharyngeal squamous cell carcinoma (OPC), high CD8⁺ tumor-infiltrating lymphocyte (CD8⁺TIL) density confers improved prognosis. We compared neoadjuvant durvalumab (PD-L1 inhibitor) with durvalumab + tremelimumab (CTLA-4 inhibitor) in terms of impact on CD8⁺TIL density, safety, and efficacy in patients with OPC. Patients and Methods: Patients with newly diagnosed stage II–IVA OPC or locoregionally recurrent OPC amenable to resection were included. Patients were randomized to two cycles of durvalumab or durvalumab + tremelimumab before surgery. The primary endpoint was change between baseline and resection specimen in CD8⁺TIL density between arms. Secondary endpoints included safety, response rate per RECIST, major pathologic response (MPR; ≤10% viable tumor cells) rate, and patient-reported outcomes. Results: Of 28 eligible patients (14/arm), 20 (71%) had newly diagnosed OPC, and 24 (86%) were p16-positive. The posttreatment to pretreatment median CD8⁺TIL density ratio was 1.31 for durvalumab and 1.15 for combination treatment (P = 0.97; 95% CI: −1.07–2.28). In each group, 6 patients (43%, 95% CI: 17.66–71.14) had a response. Eight patients (29%) had a MPR at the primary tumor and/or nodal metastases. Neither baseline CD8⁺TIL density nor PD-L1 expression level correlated with overall response, but a trend toward greater CD8⁺TIL change in patients with a MPR was seen (P = 0.059; 95% CI: −0.33–3.46). Four patients (14%) had grade ≥3 adverse events. At median follow-up time of 15.79 months, all patients were alive, and one had an additional recurrence. Conclusions: Durvalumab + tremelimumab did not increase CD8⁺TIL density more than durvalumab alone did. The observed safety and activity support further investigation of neoadjuvant checkpoint inhibitor for OPC.

Locoregional and distant recurrence remains common and usually fatal for patients with advanced head and neck squamous cell carcinoma (HNSCC). One promising molecular target in HNSCC is the Src family kinases (SFK). SFKs can affect cellular proliferation and survival by activating the signal transducer and activator of transcription (STAT) family of transcription factors, especially STAT3. Surprisingly, sustained SFK inhibition resulted in only transient inhibition of STAT3. We investigated the mechanism underlying STAT3 activation and its biological importance. Specific c-Src knockdown with small interfering RNA (siRNA) resulted in STAT3 activation showing specificity, which was inhibited by Janus-activated kinase (JAK; TYK2 and JAK2) depletion with siRNA. Sustained SFK inhibition also resulted in recovered JAK-STAT3 binding and JAK kinase activity after an initial reduction, although JAK phosphorylation paradoxically decreased. To determine the biological significance of STAT3 activation, we combined specific STAT3 depletion with a pharmacologic SFK inhibitor and observed increased cell cycle arrest and apoptosis. Likewise, the addition of STAT3- or JAK-specific siRNA to c-Src–depleted cells enhanced cytotoxicity relative to cells incubated with c-Src siRNA alone. These results show that reactivation of STAT3 after sustained, specific c-Src inhibition is mediated through altered JAK-STAT3 binding and JAK kinase activity and that this compensatory pathway allows for cancer cell survival and proliferation despite durable c-Src inhibition. To our knowledge, this novel feedback pathway has never been described previously. Given that pharmacologic SFK inhibitors are currently being evaluated in clinical trials, these results have potential clinical implications for cancer therapy. [Cancer Res 2009;69(5):1958–65]

BACKGROUND: The recently developed the Src and Abelson (Abl) kinase inhibitor dasatinib has antitumor effects in epithelial and mesenchymal tumors. Preclinical data have indicated that dasatinib is metabolized primarily through cytochrome P450 3A4 (CYP3A4) and may cause QT prolongation. In light of its improved tolerability, the authors were interested in the safety of a once‐daily dasatinib regimen.METHODS: The authors conducted a phase 1 trial of dasatinib in 29 patients with advanced solid tumors. Segment 1 of the trial was short term and sequential and was designed to determine whether the coadministration of the potent CYP3A4 inhibitor ketoconazole had an effect on the pharmacokinetics of dasatinib. Segment 2 was designed to evaluate the safety of dasatinib as dosing was increased. QT intervals were monitored closely in both segments. Efficacy was assessed in Segment 2 using both positron emission tomography and computed tomography.RESULTS: Hematologic toxicities were markedly less than those observed in patients with leukemia, whereas nonhematologic toxicities were similar. The authors determined that the maximum recommended dose was 180 mg once daily based on the incidence of pleural effusion. Coadministration of ketoconazole led to a marked increase in dasatinib exposure, which was correlated with an increase in corrected QT (QTc) values of approximately 6 msec. No adverse cardiac events were observed.CONCLUSIONS: The dose‐limiting toxic effect for dasatinib was pleural effusion. The pharmacokinetic and cardiac studies indicated that coadministration of dasatinib with potent CYP3A4 inhibitors or agents that prolong the QTc interval should be avoided if possible. Close monitoring for toxicity and dose reduction should be considered if the coadministration of such agents cannot be avoided. Cancer 2010. © 2010 American Cancer Society.