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Central Nervous System (CNS) Lymphomas are aggressive brain tumors with limited treatment options. Targeting the phosphoinositide 3-kinase (PI3K) pathway yields promising responses across B-cell malignancies, but its therapeutic potential in CNS lymphomas remains unexplored. We present pre-clinical and clinical data on the pan-PI3K inhibitor Buparlisib in CNS lymphomas. In a primary CNS lymphoma-patient-derived cell line, we define the EC50. Four patients with recurrent CNS lymphoma were enrolled in a prospective trial. We evaluated Buparlisib plasma and cerebrospinal fluid pharmacokinetics, clinical outcomes, and adverse events. Treatment was well tolerated. Common toxicities include hyperglycemia, thrombocytopenia, and lymphopenia. The presence of Buparlisib in plasma and CSF was confirmed 2h post-treatment with a median CSF concentration below the EC50 defined in the cell line All four patients were evaluated for response and the median time to progression was 39 days. Buparlisib monotherapy did not lead to meaningful responses and the trial was prematurely stopped.Clinical Trial Registration: NCT02301364 [ABSTRACT FROM AUTHOR]

Most glioblastoma tumours exhibit intrinsic phosphatidylinositol 3-kinase (PI3K) pathway activation. Preclinical in vitro and in vivo models suggest that buparlisib (an oral pan-PI3K inhibitor) can have an effect on glioblastoma directly and by enhancing the activity of radiation and of temozolomide. This was a phase I, two-stage, multicentre, open-label, dose-escalation study of buparlisib in combination with temozolomide and radiotherapy in patients with newly diagnosed glioblastoma. In stage I, patients who completed the concomitant phase of combination of temozolomide and radiation prior to study entry received buparlisib in combination with temozolomide. In stage II, patients received buparlisib in combination with temozolomide and radiotherapy in the concomitant phase and temozolomide in the adjuvant treatment phase. The primary objective was to estimate the maximum tolerated dose (MTD) of buparlisib when combined with the approved first-line treatment of temozolomide and radiotherapy. The MTD of buparlisib in combination with temozolomide at stage I (adjuvant phase only) was 80 mg/day, which was used as the starting dose in stage II. The MTD of buparlisib in combination with temozolomide and radiotherapy in stage II (concomitant + adjuvant phase) was not determined due to the observed dose-limiting toxicities and treatment discontinuations due to adverse events (AEs). In stage I, the most commonly reported AEs were nausea (72.7%) and fatigue (59.1%). In stage II, the most commonly reported AEs were fatigue and nausea (56.3% each). No on-treatment deaths were reported during the study. Considering that the primary objective of estimating the MTD was not achieved in addition to the observed challenging safety profile of buparlisib in combination with radiotherapy and temozolomide, Novartis decided not to pursue the development of buparlisib in newly diagnosed glioblastoma.Trial registration numberClinicalTrials.gov identifier: NCT01473901.

Oncogenic transformation of lung epithelial cells is a multistep process, frequently starting with the inactivation of tumour suppressors and subsequent development of activating mutations in proto‐oncogenes, such as members of the PI3K or MAPK families. Cells undergoing transformation have to adjust to changes, including altered metabolic requirements. This is achieved, in part, by modulating the protein abundance of transcription factors. Here, we report that the ubiquitin carboxyl‐terminal hydrolase 28 (USP28) enables oncogenic reprogramming by regulating the protein abundance of proto‐oncogenes such as c‐JUN, c‐MYC, NOTCH and ∆NP63 at early stages of malignant transformation. USP28 levels are increased in cancer compared with in normal cells due to a feed‐forward loop, driven by increased amounts of oncogenic transcription factors such as c‐MYC and c‐JUN. Irrespective of oncogenic driver, interference with USP28 abundance or activity suppresses growth and survival of transformed lung cells. Furthermore, inhibition of USP28 via a small‐molecule inhibitor resets the proteome of transformed cells towards a ‘premalignant’ state, and its inhibition synergizes with clinically established compounds used to target EGFRL858R‐, BRAFV600E‐ or PI3KH1047R‐driven tumour cells. Targeting USP28 protein abundance at an early stage via inhibition of its activity is therefore a feasible strategy for the treatment of early‐stage lung tumours, and the observed synergism with current standard‐of‐care inhibitors holds the potential for improved targeting of established tumours.

Simple Summary: Pancreatic neuroendocrine tumors (PanNETs) are often diagnosed when advanced or metastatic, and at this stage curative surgery in no longer an option. Given that available treatments for advanced disease have shown limited efficacy, novel therapies are urgently needed. In this scenario, we selected two drugs, inhibiting pathways known to be activated in PanNETs, and evaluated their efficacy in various preclinical tumor models. We chose a PI3K inhibitor (buparlisib) and a CDK4/6 inhibitor (ribociclib). We first tested these drugs, alone or in combination, on established cell lines representing distinct PanNET differentiation states. The combination buparlisib plus ribociclib reduced the proliferation of the cell lines more effectively than the single drugs. Inhibition of downstream target genes and/or proteins explained the drugs' anti-proliferative activity. Buparlisib, but not ribociclib, promoted cell death. We then demonstrated that the combination treatment with buparlisib and ribociclib inhibits the viability of primary islets from a genetic animal model of PanNETs (Men1-deficient mice), without significantly affecting viability and function of primary islets from wild-type mice. Noteworthy, treatment of primary patient-derived PanNET cultures supported the efficacy of the combination treatment. Our findings indicate that the combined inhibition of PI3K and CDK4/6 pathways is a potentially effective therapeutic option for PanNETs. Pancreatic neuroendocrine neoplasms (PanNENs) are the second most common malignancy of the pancreas. Surgery remains the only curative treatment for localized disease. For patients with inoperable advanced or metastatic disease, few targeted therapies are available, but their efficacy is unpredictable and variable. Exploiting prior knowledge on pathogenetic processes involved in PanNEN tumorigenesis, we tested buparlisib (PI3K inhibitor) and ribociclib (CDK4/6 inhibitor), as single agents or in combination, in different preclinical models. First, we used cell lines representative of well-differentiated (INS-1E, NT-3) and poorly differentiated (BON-1) PanNENs. The combination of buparlisib with ribociclib reduced the proliferation of 2D and 3D spheroid cultures more potently than the individual drugs. Buparlisib, but not ribociclib, induced apoptosis. The anti-proliferative activity of the drugs correlated with downstream target inhibition at mRNA and protein levels. We then tested the drugs on primary islet microtissues from a genetic PanNET animal model (Men1-defective mice) and from wild-type mice: the drug combination was effective against the former without altering islet cell physiology. Finally, we treated PanNET patient-derived islet-like 3D tumoroids: the combination of buparlisib with ribociclib was effective in three out of four samples. Combined targeting of PI3K and CDK4/6 is a promising strategy for PanNENs spanning various molecular and histo-pathological features. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the efficacy and safety of buparlisib, an oral pan-PI3K inhibitor, in relapsed or refractory thymomas. Methods: This was a single center, single arm, open label phase II trial of buparlisib in patients with recurrent thymoma who have progressed after at least one prior line of treatment. The primary endpoint was objective response rate (complete response [CR] + partial response [PR]). Secondary endpoints included toxicity; progression free survival (PFS); overall survival (OS); disease control rate (DCR), i.e., the percentage of patients who achieve either PR or CR or stable disease [SD] for at least 4 months. Results: Between 10/13/2014 and 1/18/2017, 14 patients with stage IV disease were enrolled. Median age was 58y (23-74). 71% were females and 71% white. All patients had WHO B2 (29%) or B3 (71%) thymoma. Patients received buparlisib for a median of 4.5m (2-33). At a median follow up of 16.6m (2.4-31.3), onr patients (7%) achieved a PR. DCR was 50%. Median PFS was 11.1m (95% CI 2.9 - 18.8). Median OS, updated as of March, 2021 was 22.5m (10.7-31.3). Most common grade 3-4 adverse events related to buparlisib were dyspnea (21%), rash (14%), elevated transaminases (14%), cough (7%), pneumonitis (7%), anxiety (7%), fatigue (7%) and hyperglycemia (7%). Reasons for treatment discontinuation included progression of disease (n= 5), rash (n=4), pulmonary toxicity (n=3), sinusitis (n=1), and disseminated toxoplasmosis plus autoimmune cholangitis (n=1). As of 3/2021, 8 patients have died, 7 due to disease progression and 1 due to central nervous system toxoplasmosis and autoimmune cholangitis. Conclusion: Buparlisib showed modest activity in patients with relapsed or refractory thymomas. Further investigation of PI3K pathway targeted therapy in thymoma is warranted. (clinicaltrials.gov ID: NCT02220855). [ABSTRACT FROM AUTHOR]

Oncogenic transformation of lung epithelial cells is a multistep process, frequently starting with the inactivation of tumour suppressors and subsequent development of activating mutations in proto-oncogenes, such as members of the PI3K or MAPK families. Cells undergoing transformation have to adjust to changes, including altered metabolic requirements. This is achieved, in part, by modulating the protein abundance of transcription factors. Here, we report that the ubiquitin carboxyl-terminal hydrolase 28 (USP28) enables oncogenic reprogramming by regulating the protein abundance of proto-oncogenes such as c-JUN, c-MYC, NOTCH and ∆NP63 at early stages of malignant transformation. USP28 levels are increased in cancer compared with in normal cells due to a feed-forward loop, driven by increased amounts of oncogenic transcription factors such as c-MYC and c-JUN. Irrespective of oncogenic driver, interference with USP28 abundance or activity suppresses growth and survival of transformed lung cells. Furthermore, inhibition of USP28 via a small-molecule inhibitor resets the proteome of transformed cells towards a ‘premalignant’ state, and its inhibition synergizes with clinically established compounds used to target EGFRL858R-, BRAFV600E- or PI3KH1047R-driven tumour cells. Targeting USP28 protein abundance at an early stage via inhibition of its activity is therefore a feasible strategy for the treatment of early-stage lung tumours, and the observed synergism with current standard-of-care inhibitors holds the potential for improved targeting of established tumours. [ABSTRACT FROM AUTHOR]

Among breast cancer (BC) patients, 15–25% develop BC brain metastases (BCBM), a severe condition due to the limited therapeutic options, which points to the need for preventive strategies. We aimed to find a drug able to boost blood–brain barrier (BBB) properties and prevent BC cells (BCCs) extravasation, among PI3K, HSP90, and EGFR inhibitors and approved drugs. We used BCCs (4T1) and BBB endothelial cells (b.End5) to identify molecules with toxicity to 4T1 cells and safe for b.End5 cells. Moreover, we used those cells in mixed cultures to perform a high-throughput microscopy screening of drugs' ability to ameliorate BBB properties and prevent BCCs adhesion and migration across the endothelium, as well as to analyse miRNAs expression and release profiles. KW-2478, buparlisib, and minocycline hydrochloride (MH) promoted maximal expression of the junctional protein β-catenin and induced 4T1 cells nucleus changes. Buparlisib and MH further decreased 4T1 adhesion. MH was the most promising in preventing 4T1 migration and BBB disruption, tumour and endothelial cytoskeleton-associated proteins modifications, and miRNA deregulation. Our data revealed MH's ability to improve BBB properties, while compromising BCCs viability and interaction with BBB endothelial cells, besides restoring miRNAs' homeostasis, paving the way for MH repurposing for BCBM prevention. [ABSTRACT FROM AUTHOR]

PurposeTo investigate the efficacy and safety of buparlisib, an oral pan-PI3K inhibitor, in relapsed or refractory thymomas.MethodsThis was a single center, single arm, open label phase II trial of buparlisib in patients with recurrent thymoma who have progressed after at least one prior line of treatment. The primary endpoint was objective response rate (complete response [CR] + partial response [PR]). Secondary endpoints included toxicity; progression free survival (PFS); overall survival (OS); disease control rate (DCR), i.e., the percentage of patients who achieve either PR or CR or stable disease [SD] for at least 4 months.ResultsBetween 10/13/2014 and 1/18/2017, 14 patients with stage IV disease were enrolled. Median age was 58y (23–74). 71% were females and 71% white. All patients had WHO B2 (29%) or B3 (71%) thymoma. Patients received buparlisib for a median of 4.5m (2–33). At a median follow up of 16.6m (2.4–31.3), onr patients (7%) achieved a PR. DCR was 50%. Median PFS was 11.1m (95% CI 2.9 – 18.8). Median OS, updated as of March, 2021 was 22.5m (10.7–31.3). Most common grade 3-4 adverse events related to buparlisib were dyspnea (21%), rash (14%), elevated transaminases (14%), cough (7%), pneumonitis (7%), anxiety (7%), fatigue (7%) and hyperglycemia (7%). Reasons for treatment discontinuation included progression of disease (n= 5), rash (n=4), pulmonary toxicity (n=3), sinusitis (n=1), and disseminated toxoplasmosis plus autoimmune cholangitis (n=1). As of 3/2021, 8 patients have died, 7 due to disease progression and 1 due to central nervous system toxoplasmosis and autoimmune cholangitis.ConclusionBuparlisib showed modest activity in patients with relapsed or refractory thymomas. Further investigation of PI3K pathway targeted therapy in thymoma is warranted. (clinicaltrials.gov ID: NCT02220855).Clinical trial registrationclinicaltrials.gov, identifier (NCT02220855)

Abstract Background Treatment options for triple-negative breast cancer remain limited. Activation of the PI3K pathway via loss of PTEN and/or INPP4B is common. Buparlisib is an orally bioavailable, pan-class I PI3K inhibitor. We evaluated the safety and efficacy of buparlisib in patients with metastatic triple-negative breast cancer. Methods This was a single-arm phase 2 study enrolling patients with triple-negative metastatic breast cancer. Patients were treated with buparlisib at a starting dose of 100 mg daily. The primary endpoint was clinical benefit, defined as confirmed complete response (CR), partial response (PR), or stable disease (SD) for ≥ 4 months, per RECIST 1.1. Secondary endpoints included progression-free survival (PFS), overall survival (OS), and toxicity. A subset of patients underwent pre- and on-treatment tumor tissue biopsies for correlative studies. Results Fifty patients were enrolled. Median number of cycles was 2 (range 1–10). The clinical benefit rate was 12% (6 patients, all SD ≥ 4 months). Median PFS was 1.8 months (95% confidence interval [CI] 1.6–2.3). Median OS was 11.2 months (95% CI 6.2–25). The most frequent adverse events were fatigue (58% all grades, 8% grade 3), nausea (34% all grades, none grade 3), hyperglycemia (34% all grades, 4% grade 3), and anorexia (30% all grades, 2% grade 3). Eighteen percent of patients experienced depression (12% grade 1, 6% grade 2) and anxiety (10% grade 1, 8% grade 2). Alterations in PIK3CA/AKT1/PTEN were present in 6/27 patients with available targeted DNA sequencing (MSK-IMPACT), 3 of whom achieved SD as best overall response though none with clinical benefit ≥ 4 months. Of five patients with paired baseline and on-treatment biopsies, reverse phase protein arrays (RPPA) analysis demonstrated reduction of S6 phosphorylation in 2 of 3 patients who achieved SD, and in none of the patients with progressive disease. Conclusions Buparlisib was associated with prolonged SD in a very small subset of patients with triple-negative breast cancer; however, no confirmed objective responses were observed. Downmodulation of key nodes in the PI3K pathway was observed in patients who achieved SD. PI3K pathway inhibition alone may be insufficient as a therapeutic strategy for triple-negative breast cancer. Trial registration NCT01790932 . Registered on 13 February 2013; NCT01629615 . Registered on 27 June 2012.

Abstract The PIKTAM study evaluated the efficacy and safety of the PI3K inhibitor buparlisib in combination with tamoxifen in hormone receptor‐positive (HR+), HER2‐negative advanced breast cancer patients after failure of prior endocrine therapy. In this open‐label, single‐arm phase II trial, 25 patients were enrolled in 11 sites in Germany. Patients were stratified according to PIK3CA mutation status (tissue and cfDNA from serum samples) and/or loss of PTEN expression. Patients received buparlisib (100 mg) and tamoxifen (20 mg) once daily on a continuous schedule (28‐day cycle) until progression or unacceptable toxicity. Primary endpoint was overall 6‐month progression‐free survival (PFS) rate. Key secondary endpoints included the 6‐month PFS rate in subpopulations, PFS, overall survival, overall response rate (ORR), disease control rate (DCR), and safety. Overall, the 6‐month PFS rate was 33.3% (n/N = 7/21, one‐sided 95% CI 16.8‐100) and median PFS was 6.1 (CI 2.6‐10.6) months. The ORR and DCR were 12.5% and 44%. The PIK3CA‐mutated subgroup consistently showed the highest 6‐month PFS rate (62.5%, n/N = 5/8), median PFS (8.7 months), ORR (40%), and DCR (80%). No new safety signals emerged. Most common adverse events were gastrointestinal disorders (56%), psychiatric/mood disorders (48%), skin rash/hypersensitivity (44%), cardiovascular (40%), and hepatic (32%) events. The trial was prematurely terminated due to the substantially altered risk‐benefit profile of buparlisib. Nevertheless, PIK3CA mutations emerged as a clinically feasible and useful biomarker for combined PI3K inhibition and endocrine therapy in patients with HR+ breast cancer. Further biomarker‐stratified studies with isoform‐specific PI3K inhibitors are warranted. EudraCT No: 2014‐000599‐24.

Non-small cell lung cancer (NSCLC) is a global health issue lacking effective treatments. Buparlisib is a pan-PI3K inhibitor that shows promising clinical results in treating NSCLC. However, chemoresistance is inevitable and hampers the application of buparlisib. Studies show that a combination of phytochemicals and chemotherapeutics enhances its effectiveness. Here, we evaluated the role of metformin, an agent with multiple pharmacological properties, in enhancing the anti-tumour activities of buparlisib against NSCLC cells. Our results showed that metformin and buparlisib synergistically inhibited cell viability, migration, and invasion of NSCLC cells. In addition, co-treatment of metformin and buparlisib also induced cell cycle arrest and cell death in NSCLC cells. Mechanistically, metformin and buparlisib repressed Mcl-1 and upregulated Puma in NSCLC cells in a p53-independent manner. Moreover, they inhibited the PI3K/Akt signalling pathway, leading to activation of the FoxO3a/Puma signalling in NSCLC cells. Our findings suggest that combined treatment of metformin and buparlisib might provide a promising strategy for treating NSCLC. • Metformin and buparlisib synergistically inhibit tumorigenesis of non-small cell lung cancer cells. • Metformin and buparlisib synergistically inhibit the PI3K/Akt signalling pathway in non-small cell lung cancer cells. • Co-treatment of Metformin and buparlisib lead to activation of the FoxO3a/Puma signalling. [ABSTRACT FROM AUTHOR]

Among breast cancer (BC) patients, 15–25% develop BC brain metastases (BCBM), a severe condition due to the limited therapeutic options, which points to the need for preventive strategies. We aimed to find a drug able to boost blood–brain barrier (BBB) properties and prevent BC cells (BCCs) extravasation, among PI3K, HSP90, and EGFR inhibitors and approved drugs. We used BCCs (4T1) and BBB endothelial cells (b.End5) to identify molecules with toxicity to 4T1 cells and safe for b.End5 cells. Moreover, we used those cells in mixed cultures to perform a high-throughput microscopy screening of drugs’ ability to ameliorate BBB properties and prevent BCCs adhesion and migration across the endothelium, as well as to analyse miRNAs expression and release profiles. KW-2478, buparlisib, and minocycline hydrochloride (MH) promoted maximal expression of the junctional protein β-catenin and induced 4T1 cells nucleus changes. Buparlisib and MH further decreased 4T1 adhesion. MH was the most promising in preventing 4T1 migration and BBB disruption, tumour and endothelial cytoskeleton-associated proteins modifications, and miRNA deregulation. Our data revealed MH’s ability to improve BBB properties, while compromising BCCs viability and interaction with BBB endothelial cells, besides restoring miRNAs’ homeostasis, paving the way for MH repurposing for BCBM prevention.

Multiple primary cancers (MPC) occurring in the same individual is considered rare but being increasingly recognized owing to the longer cancer survival nowadays. Despite of accumulating experience in diagnosis, effective treatment remains to be problematic in many scenarios. Genetic testing-based targeted therapy could be an invaluable option for both diagnosis and treatment of such patients. Here we present a 74-year-old male with triple primary cancers including kidney, prostate, and lung with metastatic tumor on the costal bones. The patient visited the hospital for persistent cough and hemoptysis, and a diagnosis of squamous cell carcinoma of the left lung was made by bioptic fiberoptic bronchoscopy. A previous history included renal cancer controlled by Sorafenib and prostate cancer controlled by Goserelin. Radiotherapy and platinum-based chemotherapy failed to help the patient and the tumor size increased over a period of 6 months. In order to seek better therapeutical options, we performed targeted sequencing using the cancerous tissues from his lung, kidney, and prostate cancers. Briefly, the results identified VHL, EGFR, PIK3CA, TP53, and AKT1 mutations in lung cancer, AKT1, FGFR2, and TP53 mutations in renal cancer, and FGFR2 mutations in prostate cancer. A combined medication targeting PIK3CA and AKT1 signaling was recommended and the patient was given BKM120 (PIK3CA, Phase III clinical trial) and MK2206 (AKT, phase III clinical trial). Revisit chest CTs after 4 months and 9 months showed a significant shrinkage of tumor size by 40% and 80%, respectively. Our experience demonstrated a good example that genetic analysis could be valuable to diagnose and precisely treat multiple primary cancers. [ABSTRACT FROM AUTHOR]

Background: Treatment options for triple-negative breast cancer remain limited. Activation of the PI3K pathway via loss of PTEN and/or INPP4B is common. Buparlisib is an orally bioavailable, pan-class I PI3K inhibitor. We evaluated the safety and efficacy of buparlisib in patients with metastatic triple-negative breast cancer.Methods: This was a single-arm phase 2 study enrolling patients with triple-negative metastatic breast cancer. Patients were treated with buparlisib at a starting dose of 100 mg daily. The primary endpoint was clinical benefit, defined as confirmed complete response (CR), partial response (PR), or stable disease (SD) for ≥ 4 months, per RECIST 1.1. Secondary endpoints included progression-free survival (PFS), overall survival (OS), and toxicity. A subset of patients underwent pre- and on-treatment tumor tissue biopsies for correlative studies.Results: Fifty patients were enrolled. Median number of cycles was 2 (range 1-10). The clinical benefit rate was 12% (6 patients, all SD ≥ 4 months). Median PFS was 1.8 months (95% confidence interval [CI] 1.6-2.3). Median OS was 11.2 months (95% CI 6.2-25). The most frequent adverse events were fatigue (58% all grades, 8% grade 3), nausea (34% all grades, none grade 3), hyperglycemia (34% all grades, 4% grade 3), and anorexia (30% all grades, 2% grade 3). Eighteen percent of patients experienced depression (12% grade 1, 6% grade 2) and anxiety (10% grade 1, 8% grade 2). Alterations in PIK3CA/AKT1/PTEN were present in 6/27 patients with available targeted DNA sequencing (MSK-IMPACT), 3 of whom achieved SD as best overall response though none with clinical benefit ≥ 4 months. Of five patients with paired baseline and on-treatment biopsies, reverse phase protein arrays (RPPA) analysis demonstrated reduction of S6 phosphorylation in 2 of 3 patients who achieved SD, and in none of the patients with progressive disease.Conclusions: Buparlisib was associated with prolonged SD in a very small subset of patients with triple-negative breast cancer; however, no confirmed objective responses were observed. Downmodulation of key nodes in the PI3K pathway was observed in patients who achieved SD. PI3K pathway inhibition alone may be insufficient as a therapeutic strategy for triple-negative breast cancer.Trial Registration: NCT01790932 . Registered on 13 February 2013; NCT01629615 . Registered on 27 June 2012. [ABSTRACT FROM AUTHOR]

Background: The phosphatidyl 3‐inositol kinase (PI3K)/Akt/mechanistic target of rapamycin (mTOR) pathway frequently is activated in patients with urothelial carcinoma (UC). In the current study, the authors performed a phase 2 study evaluating the efficacy of the pan‐isoform class I PI3K inhibitor buparlisib in patients with platinum‐refractory metastatic UC. Methods: Two cohorts were recruited: an initial genetically unselected cohort and a subsequent expansion cohort of patients with PI3K/Akt/mTOR pathway–altered tumors. The primary endpoint was the 2‐month progression‐free survival rate. A rate of ≥80% was considered promising using a Simon 2‐stage minimax design. Secondary endpoints included safety and correlation of markers of PI3K pathway activation with outcome. Results: Six of 13 evaluable patients within the initial cohort demonstrated stable disease and 1 demonstrated a partial response, which was below the cutoff of 9 patients required to proceed to stage 2. Three of the patients with stable disease and the patient with a partial response harbored somatic TSC1 alterations. Four patients subsequently were recruited onto an expansion cohort: 3 patients with TSC1 alterations and 1 patient with a PIK3CA‐activating mutation. No patient achieved disease control at 8 weeks and accrual was halted. Of the 19 patients evaluable for toxicity, 17 demonstrated treatment‐related toxicities, 2 of whom had to discontinue therapy. Conclusions: Buparlisib was found to demonstrate modest activity in patients with metastatic UC whose tumors harbored TSC1 loss of function alterations; however, this was not a robust predictor of response to buparlisib. The pattern of genetic coalterations likely influences drug sensitivity. Given the modest clinical activity and substantial toxicity of buparlisib, future trials of PI3K inhibitors in patients with UC should focus on isoform‐selective PI3K inhibitors in genomically selected patients. Lay Summary: The phosphatidyl 3‐inositol kinase (PI3K)/Akt/mechanistic target of rapamycin (mTOR) signaling pathway frequently is upregulated in patients with metastatic urothelial carcinoma (UC).This trial explored buparlisib, an inhibitor of the pathway, in patients with heavily pretreated metastatic UC.Although the drug was found to have modest efficacy, with 6 patients experiencing stable disease and 1 patient achieving a partial response at 8 weeks on therapy, significant side effects also were observed. Patients with specific genetic alterations responded to treatment.Further studies of PI3K pathway inhibition are warranted using newer agents that have superior toxicity profiles and are more selective inhibitors of the pathway. Phosphatidyl 3‐inositol kinase (PI3K) pathway inhibition with buparlisib demonstrates modest activity in patients with metastatic urothelial carcinoma, with significant toxicity. Further studies of PI3K pathway inhibition should focus on patients with select genetic alterations and use isoform‐selective inhibitors. [ABSTRACT FROM AUTHOR]

Buparlisib is an orally available pan-Class I PI3K inhibitor, that is more potent than idelalisib in vitro. Its distinct toxicities include hyperglycemia, hypertension, and mood disturbance. IND216 is a single arm phase II trial of buparlisib in Relapsed/refractory (R/R) chronic lymphocytic leukemia (CLL). Fourteen patients were enrolled, 13 were evaluable for response and toxicity. Six of 13 patients had a partial response (46%) with a median duration of response of 15.5 months, all 11 patients with tumor assessment experienced tumor shrinkage. The most common adverse events (≥15%) were hyperglycemia, fatigue, anxiety, and gastrointestinal toxicities; all were < grade 3 except for fatigue. Three patients stopped therapy for alterations in mood. Lower levels of raptor were significantly associated with greater tumor shrinkage, suggesting that raptor could be a biomarker for response. This requires further validation in a larger CLL patient cohort. The clinical activity of buparlisib is comparable to other phosphatidylinositol-3-kinase inhibitors, with a different toxicity profile. Buparlisib, an oral, pan PI3 kinase inhibitor, is associated with a 46% partial response rate among patients with relapse chronic lymphocytic leukemia (CLL). This is a similar clinical activity to other phosphatidylinositol-3-kinase inhibitors tested. However, buparlisib has a distinct toxicity profile, characterized by hyperglycemia, hypertension, and mood alteration. In agreement with our previous preclinical study, our results suggest that basal raptor expression in CLL correlates with clinical response to buparlisib. [ABSTRACT FROM AUTHOR]

The PIKTAM study evaluated the efficacy and safety of the PI3K inhibitor buparlisib in combination with tamoxifen in hormone receptor‐positive (HR+), HER2‐negative advanced breast cancer patients after failure of prior endocrine therapy. In this open‐label, single‐arm phase II trial, 25 patients were enrolled in 11 sites in Germany. Patients were stratified according to PIK3CA mutation status (tissue and cfDNA from serum samples) and/or loss of PTEN expression. Patients received buparlisib (100 mg) and tamoxifen (20 mg) once daily on a continuous schedule (28‐day cycle) until progression or unacceptable toxicity. Primary endpoint was overall 6‐month progression‐free survival (PFS) rate. Key secondary endpoints included the 6‐month PFS rate in subpopulations, PFS, overall survival, overall response rate (ORR), disease control rate (DCR), and safety. Overall, the 6‐month PFS rate was 33.3% (n/N = 7/21, one‐sided 95% CI 16.8‐100) and median PFS was 6.1 (CI 2.6‐10.6) months. The ORR and DCR were 12.5% and 44%. The PIK3CA‐mutated subgroup consistently showed the highest 6‐month PFS rate (62.5%, n/N = 5/8), median PFS (8.7 months), ORR (40%), and DCR (80%). No new safety signals emerged. Most common adverse events were gastrointestinal disorders (56%), psychiatric/mood disorders (48%), skin rash/hypersensitivity (44%), cardiovascular (40%), and hepatic (32%) events. The trial was prematurely terminated due to the substantially altered risk‐benefit profile of buparlisib. Nevertheless, PIK3CA mutations emerged as a clinically feasible and useful biomarker for combined PI3K inhibition and endocrine therapy in patients with HR+ breast cancer. Further biomarker‐stratified studies with isoform‐specific PI3K inhibitors are warranted. EudraCT No: 2014‐000599‐24. [ABSTRACT FROM AUTHOR]

Buparlisib is a selective phosphoinositide 3 kinase inhibitor currently evaluated in clinical trials. We developed and validated an LC–MS/MS coupled with a one‐step protein precipitation extraction method for the quantitation of buparlisib in rat plasma. After protein precipitation with acetonitrile, the plasma sample was analyzed using a Cortecs UPLC C18 column, with acetonitrile–0.1% formic acid as the mobile phase system. Mass spectrometric detection was conducted in positive ionization mode, with target quantitative ion pair of m/z 411.2 → 367.2 for buparlisib. The calibration curve showed good linearity (1.0–3000 ng/ml), with acceptable accuracy (RE ranging from −6.2 to 5.9%) and precision (RSD within 8.2%) values at quality control concentrations. Extraction recovery from plasma was 80.9–88.7% and the matrix effect was negligible (92.6–95.2%). The validated method presented a simple quantification method of buparlisib in detail and utilized it for a pharmacokinetic study at three dose concentrations after oral administration in Wistar rats. [ABSTRACT FROM AUTHOR]

Background: This multicenter, open‐label, phase Ib study investigated the safety and efficacy of binimetinib (MEK inhibitor) in combination with buparlisib (phosphatidylinositol 3‐kinase [PI3K] inhibitor) in patients with advanced solid tumors with RAS/RAF alterations. Materials and Methods: Eighty‐nine patients were enrolled in the study. Eligible patients had advanced solid tumors with disease progression after standard therapy and/or for which no standard therapy existed. Evaluable disease was mandatory, per RECIST version 1.1 and Eastern Cooperative Oncology Group performance status 0‐2. Binimetinib and buparlisib combinations were explored in patients with KRAS‐, NRAS‐, or BRAF‐mutant advanced solid tumors until the maximum tolerated dose and recommended phase II dose (RP2D) were defined. The expansion phase comprised patients with epidermal growth factor receptor (EGFR)‐mutant, advanced non‐small cell lung cancer, after progression on an EGFR inhibitor; advanced RAS‐ or BRAF‐mutant ovarian cancer; or advanced non‐small cell lung cancer with KRAS mutation. Results: At data cutoff, 32/89 patients discontinued treatment because of adverse events. RP2D for continuous dosing was buparlisib 80 mg once daily/binimetinib 45 mg twice daily. The toxicity profile of the combination resulted in a lower dose intensity than anticipated. Six (12.0%) patients with RAS/BRAF‐mutant ovarian cancer achieved a partial response. Pharmacokinetics of binimetinib were not altered by buparlisib. Pharmacodynamic analyses revealed downregulation of pERK and pS6 in tumor biopsies. Conclusion: Although dual inhibition of MEK and the PI3K pathways showed promising activity in RAS/BRAF ovarian cancer, continuous dosing resulted in intolerable toxicities beyond the dose‐limiting toxicity monitoring period. Alternative schedules such as pulsatile dosing may be advantageous when combining therapies. Implications for Practice: Because dysregulation of the mitogen‐activated protein kinase (MAPK) and the phosphatidylinositol 3‐kinase (PI3K) pathways are both frequently involved in resistance to current targeted therapies, dual inhibition of both pathways may be required to overcome resistance mechanisms to single‐agent tyrosine kinase inhibitors or to treat cancers with driver mutations that cannot be directly targeted. A study investigating the safety and efficacy of combination binimetinib (MEK inhibitor) and buparlisib (PI3K inhibitor) in patients harboring alterations in the RAS/RAF pathway was conducted. The results may inform the design of future combination therapy trials in patients with tumors harboring mutations in the PI3K and MAPK pathways. This article reports on the safety and efficacy of binimetinib and buparlisib combination therapy in patients with advanced solid tumors harboring selected genomic alterations in the RAS/RAF pathway. [ABSTRACT FROM AUTHOR]

Purpose: To estimate the maximum tolerated dose (MTD) and/or identify the recommended Phase II dose (RP2D) for combined INC280 and buparlisib in patients with recurrent glioblastoma with homozygous phosphatase and tensin homolog (PTEN) deletion, mutation or protein loss. Methods: This multicenter, open-label, Phase Ib/II study included adult patients with glioblastoma with mesenchymal-epithelial transcription factor (c-Met) amplification. In Phase Ib, patients received INC280 as capsules or tablets in combination with buparlisib. In Phase II, patients received INC280 only. Response was assessed centrally using Response Assessment in Neuro-Oncology response criteria for high-grade gliomas. All adverse events (AEs) were recorded and graded. Results: 33 patients entered Phase Ib, 32 with altered PTEN. RP2D was not declared due to potential drug–drug interactions, which may have resulted in lack of efficacy; thus, Phase II, including 10 patients, was continued with INC280 monotherapy only. Best response was stable disease in 30% of patients. In the selected patient population, enrollment was halted due to limited activity with INC280 monotherapy. In Phase Ib, the most common treatment-related AEs were fatigue (36.4%), nausea (30.3%) and increased alanine aminotransferase (30.3%). MTD was identified at INC280 Tab 300 mg twice daily + buparlisib 80 mg once daily. In Phase II, the most common AEs were headache (40.0%), constipation (30.0%), fatigue (30.0%) and increased lipase (30.0%). Conclusion: The combination of INC280/buparlisib resulted in no clear activity in patients with recurrent PTEN-deficient glioblastoma. More stringent molecular selection strategies might produce better outcomes. Trial registration: NCT01870726. [ABSTRACT FROM AUTHOR]

Background: This study assessed the maximum tolerated dose (MTD) of the PI3K inhibitor buparlisib given concurrently with cetuximab in recurrent and metastatic (R/M) head and neck squamous cell carcinoma (HNSCC). Methods: Twelve patients with R/M HNSCC were enrolled. Patients were given oral buparlisib starting day 7 and daily thereafter. The dose of buparlisib was escalated in a 3 + 3 design followed by a dose expansion cohort of 6 patients. The MTD of buparlisib per protocol was 100 mg daily with cetuximab given intravenously every 14 days starting day 0. Results: Ten patients had ≥2 previous treatment regimens (11 with prior cetuximab). There were no dose limiting toxicities observed during dose escalation. One patient achieved a partial response and 4 achieved stable disease. Conclusion: Based on this pilot study, buparlisib at 100 mg daily plus cetuximab proved to be well‐tolerated. Patients previously treated with cetuximab monotherapy showed benefit from this combination. [ABSTRACT FROM AUTHOR]

Purpose: Metaplastic carcinoma of the breast (MCB) is a rare cancer characterized by the histologic presence of two or more histological cell types originating from epithelial and mesenchymal stem cells. Patients with metastatic MCB have a low response rate to conventional chemotherapy and poor survival. Optimal treatment strategies for metastatic MCB are urgently needed.Methods: We retrospectively reviewed a patient who had enrolled in the phase II/III seamless study, BELLE-4 (NCT01572727). The patient's response to the study drug assessed by an investigator per protocol and clinical course were examined and compared with those of the main cohorts in the BELLE-4 study.Results: Our patient exhibited metastatic MCB and received systemic chemotherapy, paclitaxel (70 mg/m2/week) and buparlisib (80 mg/day), a pan-class I phosphatidylinositol-3 kinase (PI3K) inhibitor. The optimal response was a confirmed partial response for 17 months in total. During the compassionated use program period, the tumor regrew when buparlisib was stop because of toxicity, and responded to the treatment again after resumed the buparlisib treatment. The overall survival of the patient after the development of metastatic MCB was 42 months. She experienced grade 3 hyperglycemia similar to that observed in the main cohort.Conclusion: Buparlisib plus weekly paclitaxel might be a new treatment option for patients with metastatic MCB harboring a PIK3CA mutation. Additional prospective studies for investigating the efficacy of the proposed combination are warranted. [ABSTRACT FROM AUTHOR]

Abstract Buparlisib is a pan-class I phosphoinositide 3-kinase (PI3K) inhibitor and is currently under clinical evaluation for the treatment of different cancers. Because PI3K signalling is related to cell proliferation and resistance to chemotherapy, new therapeutic approaches are focused on combining PI3K inhibitors with other anti-cancer therapeutics. Carbonyl-reducing enzymes catalyse metabolic detoxification of anthracyclines and reduce their cytotoxicity. In the present work, the effects of buparlisib were tested on six human recombinant carbonyl-reducing enzymes: AKR1A1, AKR1B1, AKR1B10, AKR1C3, and AKR7A2 from the aldo-keto reductase superfamily and CBR1 from the short-chain dehydrogenase/reductase superfamily, all of which participate in the metabolism of daunorubicin. Buparlisib exhibited the strongest inhibitory effect on recombinant AKR1C3, with a half-maximal inhibitory concentration (IC 50) of 9.5 μM. Its inhibition constant K i was found to be 14.0 μM, and the inhibition data best fitted a mixed-type mode with α = 0.6. The same extent of inhibition was observed at the cellular level in the human colorectal carcinoma HCT 116 cell line transfected with a plasmid encoding the AKR1C3 transcript (IC 50 = 7.9 μM). Furthermore, we performed an analysis of flexible docking between buparlisib and AKR1C3 and found that buparlisib probably occupies a part of the binding site for a cofactor most likely via the trifluoromethyl group of buparlisib interacting with catalytic residue Tyr55. In conclusion, our results show a novel PI3K-independent effect of buparlisib that may improve therapeutic efficacy and safety of daunorubicin by preventing its metabolism by AKR1C3. Graphical abstract Image 1 Highlights • Buparlisib is an effective inhibitor of AKR1C3. • Buparlisib decreases metabolism of daunorubicin in cancer cells. • Inhibition of AKR1C3-mediated reduction of daunorubicin by buparlisib best fitted a mixed-type mode. • Buparlisib helps to manage anthracycline resistance and anthracycline-associated adverse effects. [ABSTRACT FROM AUTHOR]

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Abstract Background Buparlisib, a pan-phosphatidylinositol 3-kinase (PI3K) inhibitor, plus fulvestrant in the BELLE-2 study significantly improved progression-free survival (PFS) in patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative advanced breast cancer. Patients and methods In this phase III study, patients were randomised 1:1 to buparlisib (100 mg/day; continuously in 28-day cycles) or placebo, plus fulvestrant (500 mg on cycle 1 day 15, and day 1 of subsequent cycles). Overall survival (OS) was assessed in the overall population and patients with known PI3K pathway status (both had shown significant PFS improvements). OS by PIK3CA status in circulating tumour DNA (ctDNA) was an exploratory end-point. Results A total of 2025 patients were screened for eligibility between 7th September 2012 and 10th September 2014, and 1178 received fulvestrant (500 mg) during a run-in phase; 31 discontinued. Of 1147 patients (median age 62 years), 98% had the Eastern Cooperative Oncology Group performance status ≤1, and 59% had visceral disease. Median follow-up from randomisation to data cut-off (23rd December 2016) was 37.6 months. Median OS trended in favour of the buparlisib arm in the overall population (33.2 versus 30.4 months; P = 0.045) and among patients with known PI3K pathway status (30.9 versus 28.9 months; P = 0.144); neither outcome was statistically significant. Median OS also trended in favour of buparlisib among patients with PIK3CA -mutant ctDNA (26.0 versus 24.8 months). Grade III/IV adverse events with ≥10% difference between the buparlisib versus placebo arms were elevated alanine aminotransferase (26% versus 1%), elevated aspartate aminotransferase (18% versus 3%) and hyperglycemia (15% versus <1%). Conclusions OS results were in favour of buparlisib plus fulvestrant versus placebo plus fulvestrant; however, there is no statistical significance and more frequent grade III/IV adverse events were reported. Use of more selective PI3K inhibitors might provide the greatest clinical benefit and tolerable safety profile in this setting. Further evaluation of the predictive benefit of PIK3CA -mutant ctDNA is warranted. Trial registration number NCT01610284. Highlights • In this phase III study, median overall survival trended in favour of buparlisib plus fulvestrant versus placebo plus fulvestrant. ○ In the overall population (1147 patients), median OS was 33.2 versus 30.4 months; 1-sided P = 0.045. ○ In patients with known PI3K pathway status (851 patients), median OS was 30.9 versus 28.9 months; 1-sided P = 0.144. • Both outcomes were not statistically significant and more frequent grade III/IV adverse events were reported. • Investigation of selective PI3K inhibitors is warranted. [ABSTRACT FROM AUTHOR]

Alteration of the phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin signaling pathway is key for the growth and survival of several cancers, including breast cancer. In addition, dysregulation of PI3K signaling may contribute to resistance to several anticancer agents. PI3K inhibitors may, therefore, be effective as antineoplastic therapy. Buparlisib is a potent and highly specific oral inhibitor of the pan-class I PI3K family. Buparlisib specifically inhibits class I PIK3 in the PI3K/AKT kinase signaling pathway in an ATP-competitive manner, thus inhibiting the production of the secondary messenger phosphatidylinositol (3,4,5)-trisphosphate and activation of the PI3K signaling pathway. This may induce inhibition of tumor cell growth and survival in susceptible tumor cell populations. Buparlisib is currently under investigation in patients with a variety of solid tumors, including breast cancer. Buparlisib has been validated as a promising anticancer agent, and tremendous efforts have been taken to develop it. However, buparlisib monotherapy has resulted in humble benefit so far. Results from studies combining buparlisib with different anticancer agents - namely, endocrine therapy, anti-HER2 therapy, and chemotherapy - have showed variable efficacy with consistent substantial toxicity. [ABSTRACT FROM AUTHOR]

Purpose We previously reported the phase I dose escalation study of buparlisib, a pan-class 1A PI3K inhibitor, combined with platinum/taxane-based chemotherapy in patients with advanced solid tumors. The combination was well tolerated and promising preliminary efficacy was observed in PTEN deficient tumors. This phase I dose expansion study now evaluates buparlisib plus high dose carboplatin and paclitaxel in unselected patients with advanced solid tumors and buparlisib plus standard dose carboplatin and paclitaxel in patients with PTEN deficient tumors (ClinicalTrials.gov, NCT01297452). Methods There were two expansion cohorts: Cohort A received continuous buparlisib (100 mg/daily) orally plus high dose carboplatin AUC 6 and paclitaxel 200 mg/m2; Cohort B treated patients with PTEN deficient tumors only and they received the recommended phase II dose (RP2D) of continuous buparlisib (100 mg/daily) orally plus standard dose carboplatin AUC 5 and paclitaxel 175 mg/m2. Both cohorts received chemotherapy intravenously on day 1 of the 21-day cycle with pegfilgrastim support. Primary endpoint in Cohort A was to evaluate the safety and tolerability of chemotherapy dose intensification with buparlisib and in Cohort B was to describe preliminary efficacy of the combination among patients with tumors harboring a PTEN mutation or homozygous deletion. Results 14 subjects were enrolled, 7 in Cohort A and 7 in Cohort B. Dose reductions were required in 5 (71%) and 3 (43%) patients, in cohort A and B respectively. Grade 3 adverse events in Cohort A included lymphopenia ( n = 5 [71%]), hyperglycemia ( n = 2, [29%]), diarrhea ( n = 2, [29%]) and rash ( n = 2, [29%]) and in cohort B included lymphopenia ( n = 5 [71%]), hyperglycemia ( n = 4 [57%]) and neutropenia ( n = 2 [29%]. The mean number of cycles on protocol was 6. The overall objective response rate was 14% (2 /14). No objective responses were observed in the PTEN deficient cohort. Four out of 6 patients with stable disease (SD) had SD or better for ≥6 cycles, 2 of which had PTEN deficient tumors. Conclusion The addition of buparlisib to high dose carboplatin and paclitaxel was not tolerable. The combination did not reveal significant clinical activity amongst a small and heterogenous group of PTEN deficient tumors, [ABSTRACT FROM AUTHOR]

Background Phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin pathway is frequently activated in HER2-positive breast cancer and may play a major role in resistance to trastuzumab. Buparlisib is a pan-class-I PI3K inhibitor with potent and selective activity against wild-type and mutant PI3K p110 isoforms. Patients and methods PIKHER2 phase IB study aimed primarily to determine a maximum tolerated dose (MTD) and propose a recommended phase II dose (RP2D) for buparlisib in combination with lapatinib in HER2-positive, trastuzumab-resistant, advanced breast cancer. Oral buparlisib (40, 60 or 80 mg) and lapatinib (750, 1000 or 1250 mg) were administered daily. A modified continuous reassessment method using an adaptive Bayesian model guided the dose escalation of both agents. Secondary end-points included antitumour activity and pharmacokinetic (PK) assessments. Results A total of 24 patients were treated across five dose levels. Dose-limiting toxicities included transaminases elevation, vomiting, stomatitis, hyperglycemia and diarrhoea. MTD was declared at buparlisib 80 mg/d + lapatinib 1250 mg/d, but toxicities and early treatment discontinuation rate beyond cycle 1 led to select buparlisib 80 mg + lapatinib 1000 mg/d as the RP2D. Main drug-related adverse events included diarrhoea, nausea, skin rash, asthenia, depression, anxiety and transaminases increase. There was no significant evidence for drug–drug PK interaction. Disease control rate was 79% [95% confidence interval [CI] 57–92%], one patient obtained a complete remission, and six additional patients experienced stable disease for ≥ 24 weeks (clinical benefit rate of 29% [95% CI 12–51%]). Conclusion Combining buparlisib and lapatinib in HER2-positive trastuzumab-resistant advanced breast cancer was feasible. Preliminary evidence of antitumour activity was observed in this heavily pre-treated population. Trial registration ID NCT01589861 . [ABSTRACT FROM AUTHOR]

Aim The Neoadjuvant PI3K inhibition in HER2 OverExpressing Breast cancEr (NeoPHOEBE) trial evaluated the efficacy and safety of buparlisib, a pan-phosphatidylinositol 3-kinase (PI3K) inhibitor, plus trastuzumab and paclitaxel as neoadjuvant treatment for human epidermal growth factor receptor-2 positive (HER2+) breast cancer. Methods NeoPHOEBE was a neoadjuvant, phase II, randomised, double-blind study. Women with HER2+ breast cancer were randomised within two independent cohorts by PIK3CA mutation status and, in each cohort stratified by oestrogen receptor (ER) status to receive buparlisib or placebo plus trastuzumab (first 6 weeks) followed by buparlisib or placebo with trastuzumab and paclitaxel. Primary end-point was pathological complete response (pCR) rate; key secondary end-point was objective response rate (ORR) at 6 weeks. Exploratory end-points were evaluation of Ki67 levels and change in tumour infiltrating lymphocytes (TILs) in intermediate biopsies at day 15. Results Recruitment was suspended mainly due to liver toxicity after enrolment of 50 of the planned 256 patients. In each arm (buparlisib n = 25; placebo n = 25) 21 patients (84%) had wild type PIK3CA and 4 patients (16%) had mutant PIK3CA . Overall, pCR rate was similar between buparlisib and placebo arms (32.0% versus 40%; one-sided P = 0.811). A trend towards higher ORR (68.8% versus 33.3%; P = 0.053) and a significant decrease in Ki67 (75% versus 26.7%; P = 0.021) was observed in buparlisib versus placebo arm in the ER+ subgroup ( P interaction = 0.03). Conclusions Addition of the pan-PI3K inhibitor buparlisib to taxane-trastuzumab-based therapy in HER2+ early breast cancer was not feasible. However, the higher ORR and Ki67 reduction in the ER+, HER2+ subgroup indicates a potential role for PI3K-targeted therapy in this setting and may warrant further investigation with better-tolerated second-generation PI3K inhibitors. Trial registration identifier NCT01816594 . [ABSTRACT FROM AUTHOR]

Background Phosphatidylinositol-3-kinase (PI3K) and androgen receptor pathway activation is common in metastatic castration resistant prostate cancer (mCRPC). Buparlisib is an oral, pan-class I PI3 kinase inhibitor. Methods This was a multisite single arm phase II trial of buparlisib 100 mg ± enzalutamide daily in men with mCRPC whose disease progressed on or who were not candidates for docetaxel. The primary end-point was the rate of radiographic/clinical progression-free survival (PFS) at 6 months. Results Thirty men were accrued: 67% post-docetaxel; median prostate specific antigen (PSA) was 70 ng/dl, 83% had ≥4 prior therapies for mCRPC; 43% received concurrent enzalutamide. The final 6 month PFS rate was estimated to be 10% (95% confidence interval 2.5–23.6%). Median PFS was 1.9 months and was 3.5 months with concurrent enzalutamide. Median overall survival was 10.6 months. Concurrent enzalutamide led to a five-fold reduction in buparlisib concentrations. PSA declines were observed in 23%; no patients achieved a ≥50% decline, and no radiographic responses were observed. Severe adverse events occurred in four men including respiratory infection and multi-organ failure, urinary tract obstruction, confusion and one seizure in the setting of a new central nervous system (CNS) metastasis. Grade III adverse events were seen in 43% of patients; common toxicities included grade I–II weight loss, diarrhoea, nausea, fatigue, anorexia, rash, hyperglycemia and anxiety/mood disorders. Conclusions Buparlisib did not demonstrate significant activity in men with mCRPC, suggesting that PI3K inhibition is not sufficient to reverse resistant mCRPC progression. Future studies of PI3K pathway inhibitors with concurrent enzalutamide should develop optimal dosing and focus on selected patients more likely to benefit. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to compare progression-free survival, overall survival, clinical benefits, and adverse effects in postmenopausal women with hormone receptor-positive and HER2-negative breast cancer who received buparlisib plus fulvestrant against those of women who received dalpiciclib plus fulvestrant, considering ribociclib plus letrozole treatment as the reference standard., Methods: Women received buparlisib plus fulvestrant (BF cohort, n = 108), dalpiciclib plus fulvestrant (DF cohort, n = 132), or ribociclib plus letrozole (RL cohort, n = 150) until unacceptable toxicity was observed., Results: A total of 117 (89 %), 80 (74 %), and 84 (56 %) women in the BF, DF, and RL cohorts, respectively, had clinical benefits. After treatment, the clinical benefits for women and after 42 months of follow-up progression-free survival and overall survival were higher in the DF cohort than in the BF and RL cohorts (p < 0.05 for all). Neutropenia, vomiting, constipation, nausea, diarrhea, and anorexia were reported higher in women of the DF and BF cohorts than in women of the RL cohort. Leukopenia and increased levels of alanine aminotransferase and aspartate aminotransferase were reported to be higher in women in the RL cohort than in women in the DF and BF cohorts. Depression, anxiety, and increased levels of alanine aminotransferase and aspartate aminotransferase were reported to be higher in women in the BF cohort than in women in the DF and RL cohorts., Conclusions: Dalpiciclib plus fulvestrant is effective and comparatively safe in postmenopausal women with hormone receptor-positive and HER2-negative breast cancers. Dalpiciclib, buparlisib, fulvestrant, and ribociclib cause neutropenia, severe depression, adverse gastroenterological effects, and adverse hepatological effects, respectively., Competing Interests: Conflicts of Interest The authors declare no conflicts of interest., (Copyright © 2023 HCFMUSP. Published by Elsevier España, S.L.U. All rights reserved.)

Background: The phosphatidylinositol-3 kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway is dysregulated in patients with metastatic renal cell carcinoma (mRCC). Buparlisib is a pan-PI3K inhibitor with activity in advanced solid tumors. The primary objective of the current study was to determine the maximum tolerated dose (MTD) and dose-limiting toxicities of buparlisib and bevacizumab in patients with mRCC. Secondary objectives included efficacy, biomarker discovery, and additional toxicity.Methods: This was a standard 3 + 3 dose escalation study of buparlisib (at a dose of 60-100 mg/day) and bevacizumab (at a dose of 10 mg/kg every 2 weeks). After the MTD was defined, 15 patients were accrued to the expansion cohort.Results: Thirty-two patients were accrued (3 were treated at 60 mg/day, 21 were treated at 80 mg/day, 6 were treated at 100 mg/day, and 2 patients never received therapy). The majority of patients had clear cell histology (87%) and 50% had received ≥2 prior lines of therapy. The MTD of buparlisib was 80 mg/day and that of bevacizumab was 10 mg/kg every 2 weeks. A total of 28 patients discontinued therapy: 17 because of disease progression, 7 because of toxicity, and 4 for other reasons. Dose-limiting toxicities included rash/pruritis, elevated lipase/amylase, anorexia, and psychiatric disorders (suicidal ideation, depression, and cognitive disturbances). Of the 30 patients who received at least 1 dose, 13% achieved a partial response (95% confidence interval, 4%-31%). Two patients harboring activating PI3KA mutations achieved 42% and 16% maximal tumor shrinkage, respectively.Conclusions: Buparlisib at a dose of 80 mg/day with bevacizumab was found to be a tolerable regimen with preliminary activity in vascular endothelial growth factor-refractory mRCC. The benefit of this combination may be of interest for future mRCC trials, possibly in a selected patient population. Cancer 2016;122:2389-2398. © 2016 American Cancer Society. [ABSTRACT FROM AUTHOR]

Aberrations in the PI3K signaling pathway are frequently observed in patients with breast cancer. Because of that, PI3K inhibitors are attractive options for the treatment of breast cancer because PI3K is the most proximal component of the pathway other than receptor tyrosine kinases. Buparlisib is a potent and highly specific oral pan-class I PI3K inhibitor, which is currently under investigation in patients with breast cancer. In this article, we describe the PI3K signaling pathway, the prognostic value of PI3K pathway mutations, as well as the mechanism of action of buparlisib. Lastly, we discuss preliminary results of preclinical and clinical studies showing the efficacy and safety profile of this agent in breast cancer patients. [ABSTRACT FROM AUTHOR]

The pharmacokinetics (PK) and safety of single-dose buparlisib (30 mg) were assessed in subjects with mild to severe hepatic impairment (n = 6 each) relative to healthy controls (n = 13). Blood samples were collected until 336 hours postdose and evaluated by liquid chromatography tandem mass spectrometry. PK parameters (including area under the curve [AUC∞] and Cmax) were derived using noncompartmental analysis. Buparlisib was rapidly absorbed in all groups (median Tmax 1.0-1.3 h). Buparlisib exposure (AUC∞) was moderately increased in subjects with mild (geometric mean ratio [GMR] 1.16; 90%CI 0.81, 1.65), moderate (GMR 1.14; 90%CI 0.80, 1.63), or severe (GMR 1.20; 90%CI 0.84, 1.72) hepatic impairment, relative to healthy controls. Apparent oral clearance was similar across groups. Due to a higher unbound fraction in the severe group (0.21) than all other groups (0.17), subjects with severe hepatic impairment had greater exposure to unbound buparlisib (GMR relative to healthy controls: AUC∞ 1.52; 90%CI 1.09, 2.13; Cmax 1.83; 90%CI 1.42, 2.36). The results indicate that a buparlisib dose adjustment may not be necessary for patients with mild to moderate hepatic impairment. The safety and therapeutic indices should be considered before determining if a dose adjustment is appropriate for patients with severe hepatic impairment. [ABSTRACT FROM AUTHOR]