A phase Ib open-label dose escalation study of the safety, pharmacokinetics, and pharmacodynamics of cobimetinib (GDC-0973) and ipatasertib (GDC-0068) in patients with locally advanced or metastatic solid tumors.

BACKGROUND: This Phase Ib study explored combination dosing of the allosteric MEK1/2 inhibitor cobimetinib and the ATP-competitive pan-AKT inhibitor ipatasertib. METHODS: Patients with advanced solid tumors were enrolled to two dose escalation arms, each using a 3 + 3 design in 28-day cycles. In Arm A, patients received concurrent cobimetinib and ipatasertib on days 1-21. In Arm B, cobimetinib was administered intermittently with ipatasertib for 21 days. Primary objectives evaluated dose-limiting toxicities (DLTs), maximum tolerated doses (MTD), and the recommended Phase II dose (RP2D). Secondary objectives included analysis of pharmacokinetic parameters, MAPK and PI3K pathway alterations, changes in tissue biomarkers, and preliminary anti-tumor efficacy. Expansion cohorts included patients with PTEN-deficient triple-negative breast cancer and endometrial cancer. RESULTS: Among 66 patients who received ≥1 dose of study drug, all experienced an adverse event (AE). Although no DLTs were reported, 6 patients experienced Cycle 1 DLT-equivalent AEs. The most common treatment-related AEs were diarrhea, nausea, vomiting, dermatitis acneiform, and fatigue. Thirty-five (53%) patients experienced drug-related AEs of ≥ grade 3 severity. Cobimetinb/ipatasertib MTDs were 60/200 mg on Arm A and 150/300 mg on Arm B; the latter was chosen as the RP2D. No pharmacokinetic interactions were identified. Biomarker analyses indicated pathway blockade and increases in IFNγ and PD-L1 gene expression following the combination. Three patients with endometrial or ovarian cancer achieved partial response, all with PTEN-low disease and two with tumor also harboring KRAS mutation. CONCLUSION: There was limited tolerability and efficacy for this MEK and AKT inhibitor combination. Nonetheless, pharmacodynamic analyses indicated target engagement and suggest rationale for further exploration of cobimetinib or ipatasertib in combination with other anticancer agents. ClinicalTrials.gov identifier: NCT01562275.

A First-in-Human Phase I Study of the ATP-Competitive AKT Inhibitor Ipatasertib Demonstrates Robust and Safe Targeting of AKT in Patients with Solid Tumors.

Activation of AKT signaling by PTEN loss or PIK3CA mutations occurs frequently in human cancers, but targeting AKT has been difficult due to the mechanism-based toxicities of inhibitors that target the inactive conformation of AKT. Ipatasertib (GDC-0068) is a novel selective ATP-competitive small-molecule inhibitor of AKT that preferentially targets active phosphorylated AKT (pAKT) and is potent in cell lines with evidence of AKT activation. In this phase I study, ipatasertib was well tolerated; most adverse events were gastrointestinal and grade 1-2 in severity. The exposures of ipatasertib ≥200 mg daily in patients correlated with preclinical TGI90, and pharmacodynamic studies confirmed that multiple targets (i.e., PRAS40, GSK3ß, and mTOR) were inhibited in paired on-treatment biopsies. Preliminary antitumor activity was observed; 16 of 52 patients (30%), with diverse solid tumors and who progressed on prior therapies, had radiographic stable disease, and many of their tumors had activation of AKT. SIGNIFICANCE: Potent inhibition of AKT signaling with ipatasertib was associated with a tolerable safety profile and meaningful disease control in a subgroup of patients. Targeting pAKT with an ATP-competitive inhibitor provides a greater therapeutic window than allosteric inhibitors. Further investigation with ipatasertib is ongoing in phase II studies. Cancer Discov; 7(1); 102-13. ©2016 AACR.This article is highlighted in the In This Issue feature, p. 1.

A randomized controlled trial of a cardiopulmonary resuscitation video in advance care planning for progressive pancreas and hepatobiliary cancer patients.

BACKGROUND: Cardiopulmonary resuscitation (CPR) is an important advance directive (AD) topic in patients with progressive cancer; however such discussions are challenging. OBJECTIVE: This study investigates whether video educational information about CPR engenders broader advance care planning (ACP) discourse. METHODS: Patients with progressive pancreas or hepatobiliary cancer were randomized to an educational CPR video or a similar CPR narrative. The primary end-point was the difference in ACP documentation one month posttest between arms. Secondary end-points included study impressions; pre- and post-intervention knowledge of and preferences for CPR and mechanical ventilation; and longitudinal patient outcomes. RESULTS: Fifty-six subjects were consented and analyzed. Rates of ACP documentation (either formal ADs or documented discussions) were 40% in the video arm (12/30) compared to 15% in the narrative arm (4/26), OR=3.6 [95% CI: 0.9-18.0], p=0.07. Post-intervention knowledge was higher in both arms. Posttest, preferences for CPR had changed in the video arm but not in the narrative arm. Preferences regarding mechanical ventilation did not change in either arm. The majority of subjects in both arms reported the information as helpful and comfortable to discuss, and they recommended it to others. More deaths occurred in the video arm compared to the narrative arm, and more subjects died in hospice settings in the video arm. CONCLUSIONS: This pilot randomized trial addressing downstream ACP effects of video versus narrative decision tools demonstrated a trend towards more ACP documentation in video subjects. This trend, as well as other video effects, is the subject of ongoing study.

gamma-Secretase inhibitors abrogate oxaliplatin-induced activation of the Notch-1 signaling pathway in colon cancer cells resulting in enhanced chemosensitivity.

Because Notch signaling is implicated in colon cancer tumorigenesis and protects cells from apoptosis by inducing prosurvival targets, it was hypothesized that inhibition of Notch signaling with gamma-secretase inhibitors (GSI) may enhance the chemosensitivity of colon cancer cells. We first show that the Notch-1 receptor, as well as its downstream target Hes-1, is up-regulated with colon cancer progression, similar to other genes involved in chemoresistance. We then report that chemotherapy induces Notch-1, as oxaliplatin, 5-fluorouracil (5-FU), or SN-38 (the active metabolite of irinotecan) induced Notch-1 intracellular domain (NICD) protein and activated Hes-1. Induction of NICD by oxaliplatin was caused by an increase in the activity and expression of gamma-secretase complex, as suppression of the protein subunit nicastrin with small interfering RNA (siRNA) prevented NICD induction after oxaliplatin. Subsequent inhibition of Notch-1 signaling with a sulfonamide GSI (GSI34) prevented the induction of NICD by chemotherapy and blunted Hes-1 activation. Blocking the activation of Notch signaling with GSI34 sensitized cells to chemotherapy and was synergistic with oxaliplatin, 5-FU, and SN-38. This chemosensitization was mediated by Notch-1, as inhibition of Notch-1 with siRNA enhanced chemosensitivity whereas overexpression of NICD increased chemoresistance. Down-regulation of Notch signaling also prevented the induction of prosurvival pathways, most notably phosphoinositide kinase-3/Akt, after oxaliplatin. In summary, colon cancer cells may up-regulate Notch-1 as a protective mechanism in response to chemotherapy. Therefore, combining GSIs with chemotherapy may represent a novel approach for treating metastatic colon cancers by mitigating the development of chemoresistance.