AKT/mTOR signaling modulates resistance to endocrine therapy and CDK4/6 inhibition in metastatic breast cancers.

Endocrine therapy (ET) in combination with CDK4/6 inhibition is routinely used as first-line treatment for HR+/HER2- metastatic breast cancer (MBC) patients. However, 30-40% of patients quickly develop disease progression. In this open-label multicenter clinical trial, we utilized a hypothesis-driven protein/phosphoprotein-based approach to identify predictive markers of response to ET plus CDK4/6 inhibition in pre-treatment tissue biopsies. Pathway-centered signaling profiles were generated from microdissected tumor epithelia and surrounding stroma/immune cells using the reverse phase protein microarray. Phosphorylation levels of the CDK4/6 downstream substrates Rb (S780) and FoxM1 (T600) were higher in patients with progressive disease (PD) compared to responders (p = 0.02). Systemic PI3K/AKT/mTOR activation in tumor epithelia and stroma/immune cells was detected in patients with PD. This activation was not explained by underpinning genomic alterations alone. As the number of FDA-approved targeted compounds increases, functional protein-based signaling analyses may become a critical component of response prediction and treatment selection for MBC patients.

Impact of genomic assays on treatment and outcomes in locally advanced breast cancer.

PURPOSE: Genomic profiling in early-stage breast cancer provides prognostic and predictive information. Genomic profiling assays have not been validated in locally advanced breast cancer (LABC). We examined a large cancer registry to evaluate genomic profiling in LABC and its effect on treatment decisions and survival. METHODS: Females with ER+/HER2- LABC who did not receive neoadjuvant therapy were selected from the National Cancer Database 2004-2017. We compared characteristics between patients with and without genomic profiling and with low genomic risk, 21-gene recurrence score ≤ 25 or low-risk 70-gene signature, treated with endocrine therapy ± chemotherapy. Propensity score methods were utilized to account for covariates that may have predicted treatment. Univariable and multivariable survival analyses were performed. RESULTS: Of 18,437 patients with LABC, 1258 (7%) had genomic profiling and 1022 (81%) had low genomic risk results. 562 patients (55%) with low genomic risk received chemotherapy and endocrine therapy (chemoendocrine). Patients who received chemoendocrine therapy were younger, had fewer comorbidities, presented with higher stage disease, had higher grade tumors, more frequently had partial mastectomy, and more often received radiation than those who received endocrine therapy alone. On multivariable analysis, endocrine therapy alone was associated with worse OS compared to chemoendocrine therapy (HR 1.77, 95% CI 1.13-2.78, p = 0.013). CONCLUSION: In women with LABC and low genomic risk, endocrine therapy alone was associated with worse OS compared to chemoendocrine therapy. This suggests that genomic profiling is not predictive in LABC. Accordingly, genomic profiling should not be routinely utilized to make adjuvant treatment decisions in LABC in the absence of further data which shows a benefit.

Phase I study of nelfinavir in liposarcoma.

PURPOSE: HIV protease inhibitors are associated with HIV protease inhibitor-related lipodystrophy syndrome. We hypothesized that liposarcomas would be similarly susceptible to the apoptotic effects of an HIV protease inhibitor, nelfinavir. METHODS: We conducted a phase I trial of nelfinavir for liposarcomas. There was no limit to prior chemotherapy. The starting dose was 1,250 mg twice daily (Level 1). Doses were escalated in cohorts of three to a maximally evaluated dose of 4,250 mg (Level 5). One cycle was 28 days. Steady-state pharmacokinetics (PKs) for nelfinavir and its primary active metabolite, M8, were determined at Levels 4 (3,000 mg) and 5. RESULTS: Twenty subjects (13 males) were enrolled. Median (range) age was 64 years (37-81). One subject at Level 1 experienced reversible, grade 3 pancreatitis after 1 week and was replaced. No other dose-limiting toxicities were observed. Median (range) number of cycles was 3 (0.6-13.5). Overall best responses observed were 1 partial response, 1 minor response, 4 stable disease, and 13 progressive disease. Mean peak plasma levels and AUCs for nelfinavir were higher at Level 4 (7.3 mg/L; 60.9 mg/L × h) than 5 (6.3 mg/L; 37.7 mg/L × h). The mean ratio of M8:nelfinavir AUCs for both levels was ~1:3. CONCLUSIONS: PKs demonstrate auto-induction of nelfinavir clearance at the doses studied, although the mechanism remains unclear. Peak plasma concentrations were within range where anticancer activity was demonstrated in vitro. M8 metabolite is present at ~1/3 the level of nelfinavir and may also contribute to the anticancer activity observed.

Tandem high-dose chemotherapy followed by autologous transplantation in patients with locally advanced or metastatic sarcoma.

BACKGROUND: Patients with locally advanced or metastatic/recurrent soft tissue and Ewing's sarcoma (EWS) have few treatment options. The purpose of our phase II study was to assess the feasibility, safety and efficacy of tandem high-dose chemotherapy (HDCT) followed by autologous stem cell transplantation (ASCT) in such patients. PATIENTS AND METHODS: Thirteen patients were enrolled onto this study. The first cycle of HDCT consisted of doxorubicin (150 mg/m(2)) and ifosfamide (14 g/m(2)) mixed with mesna (14 g/m(2)), while the second cycle consisted of melphalan (150 mg/m(2)) and cisplatin (200 mg/m(2)). RESULTS: Eleven out of 13 patients were able to complete both cycles of HDCT. No treatment-related mortality occurred and grade 3 or 4 toxicity was clinically tolerable. The 5-year progression-free survival (PFS) and overall survival (OS) for all patients was 23% (confidence interval, CI: 0-46%) and 31% (CI: 14-70%), respectively. Out of the four patients still alive, two had EWS and measurable disease at the time of ASCT and achieved a complete remission, remaining progression free 126 and 155 months after ASCT. CONCLUSION: Our study demonstrates the feasibility and safety of tandem HDCT in patients with high-risk or metastatic/recurrent sarcoma, with some patients achieving long-term PFS and OS.