Purpose: Wee1 tyrosine kinase phosphorylates and inactivates cyclin-dependent kinase (Cdk) 1/2 in response to DNA damage. AZD1775 is a first-in-class inhibitor of Wee1 kinase with single-agent antitumor activity in preclinical models. We conducted a phase I study of single-agent AZD1775 in adult patients with refractory solid tumors to determine its maximum-tolerated dose (MTD), pharmacokinetics, and modulation of phosphorylated Tyr15-Cdk (pY15-Cdk) and phosphorylated histone H2AX (γH2AX) levels in paired tumor biopsies. Patients and Methods: AZD1775 was administered orally twice per day over 2.5 days per week for up to 2 weeks per 21-day cycle (3 + 3 design). At the MTD, paired tumor biopsies were obtained at baseline and after the fifth dose to determine pY15-Cdk and γH2AX levels. Six patients with BRCA-mutant solid tumors were also enrolled at the MTD. Results: Twenty-five patients were enrolled. The MTD was established as 225 mg twice per day orally over 2.5 days per week for 2 weeks per 21-day cycle. Confirmed partial responses were observed in two patients carrying BRCA mutations: one with head and neck cancer and one with ovarian cancer. Common toxicities were myelosuppression and diarrhea. Dose-limiting toxicities were supraventricular tachyarrhythmia and myelosuppression. Accumulation of drug (t_1/2 approximately 11 hours) was observed. Reduction in pY15-Cdk levels (two of five paired biopsies) and increases in γH2AX levels (three of five paired biopsies) were demonstrated. Conclusion: This is the first report of AZD1775 single-agent activity in patients carrying BRCA mutations. Proof-of-mechanism was demonstrated by target modulation and DNA damage response in paired tumor biopsies.

Wee1, a protein kinase, regulates the G2 checkpoint in response to DNA damage. Preclinical studies have elucidated the role of wee1 in DNA damage repair and the stabilization of replication forks, supporting the validity of wee1 inhibition as a viable therapeutic target in cancer. MK-1775, a selective and potent small-molecule inhibitor of wee1, is under clinical development as a potentiator of DNA damage caused by cytotoxic chemotherapies. We present a review of the role of wee1 in the cell cycle and DNA replication and summarize the clinical development to date of this novel class of anticancer agents.

Purpose: Alveolar soft part sarcoma (ASPS) is a rare, highly vascular tumor, for which no effective standard systemic treatment exists for patients with unresectable disease. Cediranib is a potent, oral small-molecule inhibitor of all three vascular endothelial growth factor receptors (VEGFRs). Patients and Methods: We conducted a phase II trial of once-daily cediranib (30 mg) given in 28-day cycles for patients with metastatic, unresectable ASPS to determine the objective response rate (ORR). We also compared gene expression profiles in pre- and post-treatment tumor biopsies and evaluated the effect of cediranib on tumor proliferation and angiogenesis using positron emission tomography and dynamic contrast-enhanced magnetic resonance imaging. Results: Of 46 patients enrolled, 43 were evaluable for response at the time of analysis. The ORR was 35%, with 15 of 43 patients achieving a partial response. Twenty-six patients (60%) had stable disease as the best response, with a disease control rate (partial response + stable disease) at 24 weeks of 84%. Microarray analysis with validation by quantitative real-time polymerase chain reaction on paired tumor biopsies from eight patients demonstrated downregulation of genes related to vasculogenesis. Conclusion: In this largest prospective trial to date of systemic therapy for metastatic ASPS, we observed that cediranib has substantial single-agent activity, producing an ORR of 35% and a disease control rate of 84% at 24 weeks. On the basis of these results, an open-label, multicenter, randomized phase II registration trial is currently being conducted for patients with metastatic ASPS comparing cediranib with another VEGFR inhibitor, sunitinib.

Purpose: Desmoid tumors (aggressive fibromatosis) arise from connective tissue cells or fibroblasts. In general, they are slow growing and do not metastasize; however, locally aggressive desmoid tumors can cause severe morbidity and loss of function. Disease recurrence after surgery and/or radiation and diagnosis of multifocal desmoid tumors highlight the need to develop effective systemic treatments for this disease. In this study, we evaluate objective response rate after therapy with the γ-secretase inhibitor PF-03084014 in patients with recurrent, refractory, progressive desmoid tumors. Patients and Methods: Seventeen patients with desmoid tumors received PF-03084014 150 mg orally twice a day in 3-week cycles. Response to treatment was evaluated at cycle 1 and every six cycles, that is, 18 weeks, by RECIST (Response Evaluation Criteria in Solid Tumors) version 1.1. Patient-reported outcomes were measured at baseline and at every restaging visit by using the MD Anderson Symptoms Inventory. Archival tumor and blood samples were genotyped for somatic and germline mutations in APC and CTNNB1. Results: Of 17 patients accrued to the study, 15 had mutations in APC or CTNNB1 genes. Sixteen patients (94%) were evaluable for response; five (29%) experienced a confirmed partial response and have been on study for more than 2 years. Another five patients with prolonged stable disease as their best response remain on study. Patient-reported outcomes confirmed clinician reporting that the investigational agent was well tolerated and, in subgroup analyses, participants who demonstrated partial response also experienced clinically meaningful and statistically significant improvements in symptom burden. Conclusion: PF-03084014 was well tolerated and demonstrated promising clinical benefit in patients with refractory, progressive desmoid tumors who receive long-term treatment.