buparlisib and Colorectal-Neoplasms

Background Resistance to Epidermal Growth Factor inhibition (EGFRi) in patients with KRAS wild-type (wt) Colorectal Cancer (CRC) may occur as a result of PI3K/AKT/mTOR signaling. We conducted a study to establish the recommended phase II dose (RP2D) and response rate of panitumumab, an EGFRi, plus BKM120, a PI3K inhibitor, in advanced CRC. Methods Patients with chemotherapy refractory KRAS wt CRC, who were EGFRi naive were enrolled. A 3 + 3 dose escalation design was utilized. The starting dose of panitumumab was 6 mg/kg iv every 2 weeks with BKM120 at 60 mg oral daily. Results Nineteen patients were treated and 17 were evaluable for response. The starting dose was not tolerable (mucositis, fatigue). At dose level (DL) 1, three of six patients discontinued treatment due to toxicity, DL - 1 had no significant toxicity. Panitumumab 6 mg/kg iv q 2 weeks with BKM120 60 mg given 5 out of 7 days per week was declared the RP2D. One patient (5.9%) who was PTEN and PIK3CA negative by IHC had a partial response, seven had stable disease, and nine had disease progression. Conclusion Panitumumab (6 mg/kg iv q 2 weeks) with BKM120 60 mg given 5 out of 7 days per week was declared the RP2D. Toxicities including fatigue, rash and mucositis. There was little evidence of activity in this biomarker unselected cohort.

Topics: Aged; Aged, 80 and over; Aminopyridines; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Biomarkers, Tumor; Colorectal Neoplasms; Exanthema; Fatigue; Female; Humans; Male; Middle Aged; Morpholines; Mucositis; Panitumumab; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Proto-Oncogene Proteins p21(ras); PTEN Phosphohydrolase

Buparlisib (BKM120) is an oral pan-phosphatidylinositol 3-kinase inhibitor, targeting all four isoforms of class I PI3K (α, β, γ and δ). This open-label Phase I dose-escalation study was conducted to determine the maximum tolerated dose of continuous daily buparlisib in Japanese patients with advanced solid tumors. Secondary objectives included safety and tolerability, pharmacokinetics, antitumor activity and pharmacodynamic marker changes. Fifteen patients were treated at 25 mg/day (n = 3), 50 mg/day (n = 3) and 100 mg/day (n = 9) dose levels. One dose-limiting toxicity of Grade 4 abnormal liver function occurred at 100 mg/day. Considering the safety profile and the maximum tolerated dose in the first-in-man study of buparlisib in non-Japanese patients, further dose escalation was stopped and 100 mg/day was declared the recommended dose. The most common treatment-related adverse events were rash, abnormal hepatic function (including increased transaminase levels), increased blood insulin levels and increased eosinophil count. Hyperglycemia was experienced by two patients, one Grade 1 and one Grade 4, and mood alterations were experienced by three patients, two Grade 1 and one Grade 2. Pharmacokinetic results showed that buparlisib was rapidly absorbed in a dose-proportional manner. Best overall response was stable disease for six patients, including one unconfirmed partial response. In these Japanese patients with advanced solid tumors, buparlisib had a manageable safety profile, with similar pharmacokinetics to non-Japanese patients. The recommended dose of 100 mg/day will be used in future studies of buparlisib in Japanese patients.

Topics: Adult; Aged; Aminopyridines; Antineoplastic Agents; Area Under Curve; Carcinoma, Squamous Cell; Colorectal Neoplasms; Drug Administration Schedule; Female; Head and Neck Neoplasms; Humans; Japan; Lymphatic Metastasis; Male; Maximum Tolerated Dose; Middle Aged; Morpholines; Phosphoinositide-3 Kinase Inhibitors; Treatment Outcome; Young Adult

The irinotecan-induced phosphokinome changes in colorectal cancer (CRC) cells were used to guide the selection of targeted agents to be tested in combination with irinotecan.. Phosphokinome profiling with peptide arrays of tumour samples from nude mice xenografted with HT29 cells and treated or not with an effective dose of irinotecan was used to identify signalling pathways activated by irinotecan treatment. Then, drugs targeting these pathways were combined in vitro with irinotecan to test potential synergistic effect. The interactions between these drug combinations were assessed by a dose matrix approach. Confirmation of the most potential combination has been confirmed in vivo in xenografted mice.. Irinotecan induced in vivo the activation of AKT and MEK1 phosphorylation. The dose matrix approach showed that BKM120 (PI3K inhibitor) and MEK162 (MEK inhibitor) are synergistic in vitro and in vivo with a cytostatic and cytotoxic effect, while combination of BKM120 and irinotecan or MEK162 and irinotecan are only additive or even antagonistic. However, the triple combination of SN38, BKM120 and MEK162 showed a better synergistic effect that BKM120 and MEK162, indicating that the cells need to inhibit both AKT and ERK pathways to become more sensitive to irinotecan-based chemotherapies.. Analysis of chemotherapy-induced phosphokinome changes helps to elucidate the mechanisms of drug resistance and to guide the selection of targets for combination therapies with synergistic activity.

Topics: Aminopyridines; Animals; Benzimidazoles; Camptothecin; Cell Proliferation; Colorectal Neoplasms; Drug Resistance, Neoplasm; Drug Synergism; HT29 Cells; Humans; Irinotecan; MAP Kinase Kinase 1; Mice; Molecular Targeted Therapy; Morpholines; Protein Kinase Inhibitors; Signal Transduction; Xenograft Model Antitumor Assays