Mutations in TP53 lead to a defective G1 checkpoint and the dependence on checkpoint kinase 1 (Chk1) for G2 or S phase arrest in response to DNA damage. In preclinical studies, Chk1 inhibition resulted in enhanced cytotoxicity of several chemotherapeutic agents. The high frequency of TP53 mutations in triple negative breast cancer (TNBC: negative for estrogen receptor, progesterone receptor, and HER2) make Chk1 an attractive therapeutic target. UCN-01, a non-selective Chk1 inhibitor, combined with irinotecan demonstrated activity in advanced TNBC in our Phase I study. The goal of this trial was to further evaluate this treatment in women with TNBC. Patients with metastatic TNBC previously treated with anthracyclines and taxanes received irinotecan (100–125 mg/m2 IV days 1, 8, 15, 22) and UCN-01 (70 mg/m2 IV day 2, 35 mg/m2 day 23 and subsequent doses) every 42-day cycle. Peripheral blood mononuclear cells (PBMC) and tumor specimens were collected. Twenty five patients were enrolled. The overall response (complete response (CR) + partial response (PR)) rate was 4 %. The clinical benefit rate (CR + PR + stable disease ≥6 months) was 12 %. Since UCN-01 inhibits PDK1, phosphorylated ribosomal protein S6 (pS6) in PBMC was assessed. Although reduced 24 h post UCN-01, pS6 levels rose to baseline by day 8, indicating loss of UCN-01 bioavailability. Immunostains of γH2AX and pChk1S296 on serial tumor biopsies from four patients demonstrated an induction of DNA damage and Chk1 activation following irinotecan. However, Chk1 inhibition by UCN-01 was not observed in all tumors. Most tumors were basal-like (69 %), and carried mutations in TP53 (53 %). Median overall survival in patients with TP53 mutant tumors was poor compared to wild type (5.5 vs. 20.3 months, p = 0.004). This regimen had limited activity in TNBC. Inconsistent Chk1 inhibition was likely due to the pharmacokinetics of UCN-01. TP53 mutations were associated with a poor prognosis in metastatic TNBC.

Purpose Phosphatidylinositol-3-kinase (PI3K)/AKT pathway activation is an important endocrine resistance mechanism in estrogen receptor positive (ER+) breast cancer. After promising preclinical modeling of MK-2206, an allosteric pan-AKT inhibitor, with either estrogen-deprivation or fulvestrant, we conducted a Phase 1 trial in patients with metastatic ER+HER2− breast cancer to determine the recommended phase II treatment dose (RPTD) of MK-2206 when combined with either anastrozole, fulvestrant, or anastrozole/fulvestrant. Methods ER+ breast cancer cell lines were exposed in vitro to MK-2206 plus estrogen-deprivation with or without fulvestrant and monitored for apoptosis. A standard 3+3 design was employed to first determine the maximum tolerated dose (MTD) of MK-2206 plus anastrozole based on cycle 1 toxicity. Each cycle was 28 days. The RPTD was determined based on toxicities observed at MTD level during the first 3 cycles. Subsequent patients received MK-2206, at the RPTD determined above, and fulvestrant or anastrozole/fulvestrant to define RPTD for these additional regimens. Results MK-2206 induced apoptosis in parental ER+ but not in long term estrogen deprived cell lines, for which fulvestrant was required for apoptosis induction. Thirty one patients enrolled. The RPTD was defined as MK-2206 150 mg PO weekly with prednisone prophylaxis for each combination. Grade 3 rash was dose limiting. 42% (95% CI: 23%–63%) patients derived clinical benefit without progression within 6 months. Response was not associated with tumor PIK3CA mutation. Conclusion MK-2206 plus endocrine treatments were tolerable. MK-2206 in combination with anastrozole is being further evaluated in a phase II neoadjuvant trial for newly diagnosed ER+HER2− breast cancer.

PurposeUCN-01 (7-hydroxystaurosporine) is a multi-targeted protein kinase inhibitor that exhibits synergistic activity with DNA-damaging agents in preclinical studies. We conducted a Phase I study to determine the maximum-tolerated dose (MTD), dose-limiting toxicity (DLT), pharmacokinetic, and pharmacodynamic effects of UCN-01 and irinotecan in patients with resistant solid tumors.Experimental designPatients received irinotecan (75–125 mg/m2 IV on days 1, 8, 15, 22) and UCN-01 (50–90 mg/m2 IV on day 2 and 25–45 mg/m2 on day 23 and subsequent doses) every 42 days. Blood for pharmacokinetics of UCN-01 and irinotecan, and blood, normal rectal mucosa, and tumor biopsies for pharmacodynamic studies were obtained.ResultsTwenty-five patients enrolled to 5 dose levels. The MTD was irinotecan 125 mg/m2 on days 1, 8, 15, 22 and UCN-01 70 mg/m2 on day 2 and 35 mg/m2 on day 23. DLTs included grade 3 diarrhea/dehydration and dyspnea. UCN-01 had a prolonged half-life and a low clearance rate. There was a significant reduction in SN-38 Cmax and aminopentanocarboxylic acid (APC) and SN-38 glucuronide half-lives. Phosphorylated ribosomal protein S6 was reduced in blood, normal rectal mucosa, and tumor biopsies at 24 h post-UCN-01. Two partial responses were observed in women with ER, PgR, and HER2-negative breast cancers (TBNC). Both tumors were defective for p53. Twelve patients had stable disease (mean duration 18 weeks, range 7–30 weeks).ConclusionUCN-01 and irinotecan demonstrated acceptable toxicity and target inhibition. Anti-tumor activity was observed and a study of this combination in women with TNBC is underway.Electronic supplementary materialThe online version of this article (doi:10.1007/s00280-010-1410-1) contains supplementary material, which is available to authorized users.

Docosahexaenoic acid-paclitaxel administered weekly to a maximum dose of 600 mg/m(2) was well-tolerated. The slow release of paclitaxel from DHA-paclitaxel and the weekly schedule approximates continuous infusion paclitaxel which may be more active than every 3 week or weekly taxanes.

Purpose: Lack of trust and rapport with health care providers has been identified in the under-representation of racial/ethnic minorities within clinical trials. Our study used a coach to promote trust among minority patients with advanced cancer.