Dose optimization for cancer treatments with considerations for late-onset toxicities.

Given that novel anticancer therapies have different toxicity profiles and mechanisms of action, it is important to reconsider the current approaches for dose selection. In an effort to move away from considering the maximum tolerated dose as the optimal dose, the Food and Drug Administration Project Optimus points to the need of incorporating long-term toxicity evaluation, given that many of these novel agents lead to late-onset or cumulative toxicities and there are no guidelines on how to handle them. Numerous methods have been proposed to handle late-onset toxicities in dose-finding clinical trials. A summary and comparison of these methods are provided. Moreover, using PI3K inhibitors as a case study, we show how late-onset toxicity can be integrated into the dose-optimization strategy using current available approaches. We illustrate a re-design of this trial to compare the approach to those that only consider early toxicity outcomes and disregard late-onset toxicities. We also provide proposals going forward for dose optimization in early development of novel anticancer agents with considerations for late-onset toxicities.

Follicular Lymphoma: a Focus on Current and Emerging Therapies

Follicular lymphoma (FL) is the most common indolent lymphoma and is characterized by a relapsing and remitting course. In addition to significant biologic heterogeneity, the clinical trajectory for patients is variable, with some being observed for many years, and others having aggressive disease requiring multiple treatment courses. Unfortunately, FL remains incurable, and continues to cause early mortality. Improved understanding of the genetic and immune biology of FL has led to several FDA-approved therapies in the relapsed and refractory setting, including PI3K inhibitors; immunomodulatory agents; the EZH2 inhibitor, tazemetostat; and anti-CD19 chimeric antigen receptor (CAR) T-cell therapy, axicabtagene ciloleucel. This review outlines the current approach to the diagnosis and treatment of FL with a focus on emerging investigational therapies, including targeted protein inhibitors, antibody-drug conjugates, monoclonal antibodies, bispecific antibodies, and novel combination strategies.

Ghrelin signaling in dCA1 suppresses neuronal excitability and impairs memory acquisition via PI3K/Akt/GSK-3ß cascades.

Ghrelin is a circulating peptide hormone that promotes feeding and regulates metabolism in humans and rodents. The action of ghrelin is mediated by the growth hormone secretagogue receptor type 1a (GHSR-1a) that is widely distributed in the brain, including the hippocampus. Studies have demonstrated the critical role of hippocampal ghrelin/GHS-R1a signaling in synaptic physiology and memory. However, those findings are controversial, and the mechanism underlying ghrelin modulation of learning and memory is uncertain. Here, we report that micro-infusion of ghrelin in the CA1 region of the dorsal hippocampus during training specifically impairs memory acquisition. The activation of GHS-R1a and the subsequent PI3K/Akt/GSK3ß signaling cascades are involved in this process. Moreover, we report that bath application of ghrelin suppresses the intrinsic excitability of dCA1 pyramidal neurons through activating GHS-R1a, and PI3K inhibitor LY294002 blocks ghrelin's effect. However, LY294002 fails to rescue ghrelin-induced LTP impairment. Our findings support an adverse effect of ghrelin-dependent activation of GHS-R1a on memory acquisition, and suggest that PI3K/Akt/GSK3ß signaling-dependent repression of neuronal intrinsic excitability is an important novel mechanism underlying memory inhibition of ghrelin in the hippocampus.

(-)-4-O-(4-O-ß-D-glucopyranosylcaffeoyl) quinic acid enhanced the efficacy of anti-PD-L1 against esophageal carcinoma through inhibiting PI3K pathway.

PURPOSE: Using antibodies to block the programmed cell death 1 (PD-1)/programmed cell death-ligand 1 (PD-L1) pathway as an immunotherapy has achieved great success in the clinical treatment of various types of carcinoma. However, the efficacy is limited because of tumor-mediated immune immunosuppression and evasion. This study demonstrated that inhibiting the PI3K pathway with (-)-4-O-(4-O-ß-D-glucopyranosylcaffeoyl) quinic acid (QA), a new compound from endophytic fungus Penicillium citrinum of Avicennia marina, enhanced the therapeutic efficacy of anti-PD-L1 antibody against esophageal tumors. MATERIALS AND METHODS: mEC25 cells were injected into C57BL/6 mice to establish a syngeneic esophageal tumor model. Tumor infiltration lymphocytes (TILs) were analyzed by flow cytometry. Gene and protein expression was detected by qPCR and western blot, respectively. Moreover, the therapeutic effects of QA combining with anti-PD-L1 antibody were evaluated in the tumor model. RESULTS: These data demonstrated that inhibition of PI3K with QA could overcome immunosuppression and promote the response of T-lymphocytes, resulting in the restoration of cytotoxic T cell-mediated tumor control. QA and anti-PD-L1 combination therapy significantly delayed tumor growth. CONCLUSIONS: Our results provide a scientific basis to develop combination therapies involving anti-PD-L1 and PI3K inhibitors to improve responses in patients with esophageal cancer.

BET protein inhibition evidently enhances sensitivity to PI3K/mTOR dual inhibition in intrahepatic cholangiocarcinoma.

Intrahepatic cholangiocarcinoma (ICC), the second most common primary liver cancer, is a fatal malignancy with a poor prognosis and only very limited therapeutic options. Although molecular targeted therapy is emerged as a promising treatment strategy, resistance to molecular-targeted therapy occurs inevitably, which represents a major clinical challenge. In this study, we confirmed that mammalian target of rapamycin (mTOR) signaling is the most significantly affected pathways in ICC. As a novel phosphoinositide 3-kinase (PI3K)/mTOR dual inhibitor, BEZ235, exerts antitumour activity by effectively and specifically blocking the dysfunctional activation of the PI3K/serine/threonine kinase (AKT)/mTOR pathway. We generate the orthotopic ICC mouse model through hydrodynamic transfection of AKT and yes-associated protein (YAP) plasmids into the mouse liver. Our study confirmed that BEZ235 can suppress the proliferation, invasion and colony conformation abilities of ICC cells in vitro but cannot effectively inhibit ICC progression in vivo. Inhibition of PI3K/mTOR allowed upregulation of c-Myc and YAP through suppressed the phosphorylation of LATS1. It would be a novel mechanism that mediated resistance to PI3K/mTOR dual inhibitor. However, Bromo- and extraterminal domain (BET) inhibition by JQ1 downregulates c-Myc and YAP transcription, which could enhance the efficacy of PI3K/mTOR inhibitors. The efficacy results of combination therapy exhibited effective treatment on ICC in vitro and in vivo. Our data further confirmed that the combination of PI3K/mTOR dual inhibitor and BET inhibition induces M1 polarization and suppresses M2 polarization in macrophages by regulating the expression of HIF-1α. Our study provides a novel and efficient therapeutic strategy in treating primary ICC.

Fimepinostat (CUDC-907) in patients with relapsed/refractory diffuse large B cell and high-grade B-cell lymphoma: report of a phase 2 trial and exploratory biomarker analyses.

Fimepinostat (CUDC-907), a first-in-class oral small-molecule inhibitor of histone deacetylase and phosphatidylinositol 3-kinase, demonstrated efficacy in a phase 1 study of patients with relapsed/refractory (R/R) diffuse large and high-grade B-cell lymphomas (DLBCL/HGBL), particularly those with increased MYC protein expression and/or MYC gene rearrangement/copy number gain (MYC-altered disease). Therefore, a phase 2 study of fimepinostat was conducted in this patient population with 66 eligible patients treated. The primary end-point of overall response (OR) rate for patients with MYC-IHC ≥40% (n = 46) was 15%. Subsequently, exploratory pooled analyses were performed including patients treated on both the phase 1 and 2 studies based upon the presence of MYC-altered disease as well as a biomarker identified by Virtual Inference of Protein activity by Enriched Regulon analysis (VIPER). For these patients with MYC-altered disease (n = 63), the overall response (OR) rate was 22% with seven responding patients remaining on treatment for approximately two years or longer, and VIPER yielded a three-protein biomarker classification with positive and negative predictive values of ≥85%. Prolonged durations of response were achieved by patients with MYC-altered R/R DLBCL/HGBL treated with single-agent fimepinostat. Combination therapies and/or biomarker-based patient selection strategies may lead to higher response rates in future clinical trials.

The effectiveness of monotherapy with PI3K/AKT/mTOR pathway inhibitors in ovarian cancer: A meta-analysis.

OBJECTIVE: To determine the clinical benefit of monotherapy with PI3K/AKT/mTOR inhibitors in patients diagnosed with advanced or recurrent ovarian cancer and to investigate the predictive value of current PI3K/AKT/mTOR biomarkers on therapy response. METHODS: A systematic search was conducted in PubMed, Embase and the Cochrane Library for articles reporting on treatment with PI3K/AKT/mTOR inhibitors in ovarian cancer. The primary endpoint was defined as the clinical benefit rate (CBR), including the proportion of patients with complete (CR) and partial response (PR) and stable disease (SD). Secondary endpoints included the overall response rate (ORR, including CR and PR) and drug-related grade 3 and 4 adverse events. RESULTS: We included 233 patients from 19 studies and observed a pooled CBR of 32% (95% CI 20-44%) and ORR of 3% (95% CI 0-6%) in advanced or recurrent ovarian cancer patients treated with PI3K/AKT/mTOR inhibitors. Subgroup analysis tended to favor the studies who selected patients based on current PI3K/AKT/mTOR biomarker criteria (e.g. genomic alterations or loss of PTEN protein expression), but the difference in CBR was not statistically significant from studies with unselected populations (respectively, CBR of 42% (95% CI 23-62%) and 27% (95% CI 14-42%), P = 0.217). To better reflect true patient benefit, we excluded SD <6 months as a beneficial outcome which resulted in a pooled CBR of 7% (95% CI 2-13%). The overall proportion of patients with drug-related grade 3 and 4 adverse events was 36%. CONCLUSIONS: The efficacy of monotherapy with PI3K/AKT/mTOR inhibitors in advanced recurrent ovarian cancer patients is limited to a small subgroup and selection of patients with the use of current biomarkers did not improved the CBR significantly. Given the toxicity profile, we suggest that current treatment with PI3K/AKT/mTOR inhibitors should not be initiated unless in clinical trials. Furthermore, improved biomarkers to measure functional PI3K/AKT/mTOR pathway activity are needed to optimize patient selection.

Phase I trial of copanlisib, a selective PI3K inhibitor, in combination with cetuximab in patients with recurrent and/or metastatic head and neck squamous cell carcinoma.

Background The phosphatidylinositol-3 kinase pathway is often altered in head and neck squamous cell carcinoma (HNSCC), and is involved in the resistance to EGFR inhibitors. Objective We investigated the dose-limiting toxicities (DLTs), maximum tolerated dose, pharmacokinetics, and preliminary efficacy of the combination of copanlisib, an intravenous, pan-class I PI3K inhibitor, with the anti-EGFR monoclonal antibody cetuximab in recurrent and/or metastatic HNSCC patients in a phase I dose-escalation trial. Patients and methods Copanlisib was given intravenously on days 1, 8, and 15 of 28-day cycles at the dose of 45 mg and 30 mg, in combination with standard doses of weekly cetuximab (400 mg/m2 loading dose followed by 250 mg/m2 on days 8, 15, and 22, and weekly thereafter). Results Three patients received copanlisib 45 mg, of whom two experienced grade 3 hyperglycemia during Cycle 1 that met the DLT criteria. Eight patients were then treated with copanlisib at the dose of 30 mg. Because of the occurrence of hyperglycemia, a premedication with metformine was introduced on the day of the injections. No DLTs were reported at this dose level. The trial was stopped early because of the unfavourable toxicity profile of the combination. Among eight evaluable patients for response, four patients (50%) had disease stabilization according to RECIST1.1 as best response. Conclusion Copanlisib combined with cetuximab demonstrated unfavorable toxicity and limited efficacy in heavily pretreated recurrent and/or metastatic HNSCC patients.Trial registration NCT02822482, Date of registration: June 2016.

Ziziphus jujuba Mill. leaf extract restrains adipogenesis by targeting PI3K/AKT signaling pathway.

The escalation in the global prevalence of obesity has focused attention on finding novel approaches for its management. Ziziphus jujuba Mill. (ZJL) leaf extract is reported as a traditional remedy for diverse pathological conditions, including obesity. The present study investigated whether ZJL affects adipogenic differentiation in human adipocytes. Additionally, following metabolite profiling of the extract, apigenin (APG), betulinic acid (BA) and maslinic acid (MA) were selected for biological activity evaluation. The possible interactions between APG, BA, MA and target proteins with a central role in adipogenesis were assessed through molecular docking. The potential mechanisms of ZJL, APG, BA and MA were identified using transcriptional analysis through real-time quantitative PCR and protein abundance evaluation by Western blotting. The obtained results revealed a concentration-dependent reduction of accumulated lipids after ZJL, BA and MA application. The key adipogenic transcription factors peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT-enhancer-binding protein alpha (C/EBPα) were strongly decreased at a protein level by all treatments. Moreover, the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway was found to be involved in the anti-adipogenic effect of ZJL, APG and BA. Collectively, our findings indicate that ZJL and its pure compounds hampered adipocyte differentiation through PI3K/AKT inhibition. Among the selected compounds, BA exhibits the most promising anti-adipogenic activity. Furthermore, being a complex mixture of phytochemicals, the ZJL extract could be utilized as source of yet unknown bioactive leads with potential implementation in obesity management.

A retrospective observational study to evaluate the clinical outcomes and routine management of patients with chronic lymphocytic leukaemia treated with idelalisib and rituximab in the UK and Ireland (RETRO-idel).

Idelalisib (IDL) is an oral first-in-class phosphatidylinositol 3-kinase delta (PI3Kδ) inhibitor approved for chronic lymphocytic leukaemia (CLL) alongside rituximab (R) since 2014. However, little data exist on routine practice. The RETRO-idel was a protocol-led, retrospective study of 110 patients [n = 27 front-line (1L)] who received IDL-R. The primary end-point was clinical overall response rate (ORR). The median (range) follow-up of the whole cohort was 30·2 (0·1-51·9) months. The median (range) age was 72 (48-89) years. Tumour protein p53-disruption was common [100% 1L, 32·5% relapsed/refractory (R/R)]. The best ORR (intention-to-treat) was 88·2% (1L 96·3%, R/R 85·5%). Overall, the median event-free survival (mEFS) was 20·3 months and time-to-next treatment was 29·2 months. The mEFS for 1L patients was 18·7 months and R/R patients was 21·7 months. The 3-year overall survival was 56·1% (95% confidence interval 45·7-65·3). IDL was discontinued in 87·3% (n = 96). More patients discontinued due to adverse events in the front-line setting (1L 63·0% vs. R/R 44·6%) and due to progressive disease in R/R patients (20·5% vs. 3·7% in 1L). Lower respiratory tract infection/pneumonia were reported in 34·5% (Grade ≥3, 19·1%), diarrhoea in 30·9% (Grade ≥3, 6·4%), and colitis in 9·1% (Grade ≥3, 5·5%). Overall, these data describe clear efficacy for IDL-R in routine practice. No new safety signals were identified, although careful management of known toxicities is required.

Inhibition of the PI3K/mTOR Pathway in Breast Cancer to Enhance Response to Immune Checkpoint Inhibitors in Breast Cancer.

OBJECTIVES: Inhibition of the PI3K/mTOR pathway suppresses breast cancer (BC) growth, enhances anti-tumor immune responses, and works synergistically with immune checkpoint inhibitors (ICI). The objective here was to identify a subclass of PI3K inhibitors that, when combined with paclitaxel, is effective in enhancing response to ICI. METHODS: C57BL/6 mice were orthotopically implanted with syngeneic luminal/triple-negative-like PyMT cells exhibiting high endogenous PI3K activity. Tumor growth in response to treatment with anti-PD-1 + anti-CTLA-4 (ICI), paclitaxel (PTX), and either the PI3Kα-specific inhibitor alpelisib, the pan-PI3K inhibitor copanlisib, or the broad spectrum PI3K/mTOR inhibitor gedatolisib was evaluated in reference to monotherapy or combinations of these therapies. Effects of these therapeutics on intratumoral immune populations were determined by multicolor FACS. RESULTS: Treatment with alpelisib + PTX inhibited PyMT tumor growth and increased tumor-infiltrating granulocytes but did not significantly affect the number of tumor-infiltrating CD8+ T cells and did not synergize with ICI. Copanlisib + PTX + ICI significantly inhibited PyMT growth and increased activation of intratumoral CD8+ T cells as compared to ICI alone, yet did not inhibit tumor growth more than ICI alone. In contrast, gedatolisib + ICI resulted in significantly greater inhibition of tumor growth compared to ICI alone and induced durable dendritic-cell, CD8+ T-cell, and NK-cell responses. Adding PTX to this regimen yielded complete regression in 60% of tumors. CONCLUSION: PI3K/mTOR inhibition plus PTX heightens response to ICI and may provide a viable therapeutic approach for treatment of metastatic BC.

Co-occurring gain-of-function mutations in HER2 and HER3 modulate HER2/HER3 activation, oncogenesis, and HER2 inhibitor sensitivity.

Activating mutations in HER2 (ERBB2) drive the growth of a subset of breast and other cancers and tend to co-occur with HER3 (ERBB3) missense mutations. The HER2 tyrosine kinase inhibitor neratinib has shown clinical activity against HER2-mutant tumors. To characterize the role of HER3 mutations in HER2-mutant tumors, we integrate computational structural modeling with biochemical and cell biological analyses. Computational modeling predicts that the frequent HER3E928G kinase domain mutation enhances the affinity of HER2/HER3 and reduces binding of HER2 to its inhibitor neratinib. Co-expression of mutant HER2/HER3 enhances HER2/HER3 co-immunoprecipitation and ligand-independent activation of HER2/HER3 and PI3K/AKT, resulting in enhanced growth, invasiveness, and resistance to HER2-targeted therapies, which can be reversed by combined treatment with PI3Kα inhibitors. Our results provide a mechanistic rationale for the evolutionary selection of co-occurring HER2/HER3 mutations and the recent clinical observations that HER3 mutations are associated with a poor response to neratinib in HER2-mutant cancers.

Efficacy and safety of CDK4/6 and PI3K/AKT/mTOR inhibitors as second-line treatment in postmenopausal patients with hormone receptor-positive, HER-2-negative metastatic breast cancer: a network meta-analysis.

BACKGROUND: We compared the efficacy and safety of combinations of cyclin-dependent kinase 4/6 (CDK4/6) inhibitors and PI3K/AKT/mTOR inhibitors as second-line treatment in postmenopausal women with HR+, HER2- metastatic breast cancer. METHODS: We searched the Medline, Embase, and Cochrane Library electronic databases for phase II/III randomized trials evaluating CDK4/6 and PI3K/AKT/mTOR inhibitors plus fulvestrant. We compared the results with a network meta-analysis. Study quality was assessed following the GRADE approach. Outcomes of interest were progression-free survival, overall response rate, overall survival and G3-4 adverse drug events (ADEs). RESULTS: Eight RCTs were identified in the network meta-analysis. PFS was significantly improved by treatment with abemaciclib plus fulvestrant and ribociclib plus fulvestrant compared to pictilisib plus fulvestrant. The ORR following treatment with abemaciclib plus fulvestrant, ribociclib plus fulvestrant, palbociclib plus fulvestrant, buparlisib plus fulvestrant, and alpelisib plus fulvestrant significantly differed from that observed following treatment with placebo plus fulvestrant. In terms of OS, compared with placebo plus fulvestrant, abemaciclib plus fulvestrant, ribociclib plus fulvestrant, and buparlisib plus fulvestrant had a significant difference. The risks of ADEs were similar among three CDK4/6 inhibitors. CONCLUSION: As second-line treatment, three CDK4/6 inhibitors showed superior clinical efficacy compared to other PI3K/AKT/mTOR inhibitors with comparable safety profiles.

Multifunctional Nanodrug Mediates Synergistic Photodynamic Therapy and MDSCs-Targeting Immunotherapy of Colon Cancer.

An ideal tumor treatment is supposed to eliminate the primary tumor and simultaneously trigger the host antitumor immune responses to prevent tumor recurrence and metastasis. Herein, a liposome encapsulating phosphoinositide 3-kinase gamma (PI3Kγ) inhibitor IPI-549 and photosensitizer chlorin e6 (Ce6), denoted by LIC, is prepared for colon cancer treatment. LIC internalized into CT26 cells generates reactive oxygen species (ROS) under laser irradiation to cause immunogenic tumor cell death, during which immunostimulatory signals such as calreticulin are released to further induce T lymphocyte-mediated tumor cell killing. Meanwhile, IPI-549 transported by liposome can inhibit PI3Kγ in the myeloid-derived suppressive cells (MDSCs), resulting in downregulation of arginase 1 (Arg-1) and ROS to promote MDSCs apoptosis and reduce their immunosuppressive activity to CD8+ T cells. LIC-mediated immunogenic photodynamic therapy synergizes with MDSCs-targeting immunotherapy, which significantly inhibits tumor growth via facilitating the dendritic cell maturation and tumor infiltration of CD8+ T cells while decreasing the tumor infiltration of immunosuppressive regulatory T cells, MDSCs, and M2-like tumor-associated macrophages. Moreover, the synergistic therapy increases the number of effector memory T cells (TEM ) in spleen, which suggests a favorable immune memory to prevent tumor recurrence and metastasis. The Ce6 and IPI-549-coloaded multifunctional nanodrug demonstrates high efficacy in colon cancer treatment.

5-Lipoxygenase inhibition reduces inflammation and neuronal apoptosis via AKT signaling after subarachnoid hemorrhage in rats.

Early brain injury (EBI) is a major contributor to the high mortality and morbidity after subarachnoid hemorrhage (SAH). Inflammatory responses and neuronal apoptosis are important causes of EBI. Because 5- lipoxygenase (5-LOX) is known to be involved various central nervous system diseases, we investigated the effects of 5-LOX inhibition during EBI after SAH. Zileuton and LY294002 were used to inhibit expression of 5-LOX and Akt, respectively. We found that 5-LOX expression was significantly increased in the cytoplasm of cortical neurons after SAH and was accompanied by upregulated expression of the inflammatory factors LTB4, TNF-α, IL-1ß and IL-6; upregulation of the pro-apoptotic factor Bax; downregulation of the anti-apoptotic factor Bcl-2; and an increased apoptosis rate. Gastric Zileuton administration significantly suppressed all of those effects and improved neurological function. Zileuton also upregulated activated (phosphorylated) AKT levels, and these beneficial effects of Zileuton were abolished by intracerebroventricular infusion of the PI3K inhibitor LY294002. Taken together, these findings indicate that 5-LOX mediates pro-inflammatory and pro-apoptotic effects that contribute to EBI after SAH and that those effects are suppressed by activation of PI3K/Akt signaling. This suggests targeting 5-LOX may be an effective approach to treating EBI after SAH.

Copanlisib plus rituximab versus placebo plus rituximab in patients with relapsed indolent non-Hodgkin lymphoma (CHRONOS-3): a double-blind, randomised, placebo-controlled, phase 3 trial.

BACKGROUND: Copanlisib, an intravenous pan-class I PI3K inhibitor, showed efficacy and safety as monotherapy in patients with relapsed or refractory indolent non-Hodgkin lymphoma who had received at least two therapies. The CHRONOS-3 study aimed to assess the efficacy and safety of copanlisib plus rituximab in patients with relapsed indolent non-Hodgkin lymphoma. METHODS: CHRONOS-3 was a multicentre, double-blind, randomised, placebo-controlled, phase 3 study in 186 academic medical centres across Asia, Australia, Europe, New Zealand, North America, Russia, South Africa, and South America. Patients aged 18 years and older with an Eastern Cooperative Oncology Group performance status of no more than 2 and histologically confirmed CD20-positive indolent B-cell lymphoma relapsed after the last anti-CD20 monoclonal antibody-containing therapy and progression-free and treatment-free for at least 12 months, or at least 6 months for patients unwilling or unfit to receive chemotherapy, were randomly assigned (2:1) with an interactive voice-web response system via block randomisation (block size of six) to copanlisib (60 mg given as a 1-h intravenous infusion on an intermittent schedule on days 1, 8, and 15 [28-day cycle]) plus rituximab (375 mg/m2 given intravenously weekly on days 1, 8, 15, and 22 during cycle 1 and day 1 of cycles 3, 5, 7, and 9) or placebo plus rituximab, stratified on the basis of histology, progression-free and treatment-free interval, presence of bulky disease, and previous treatment with PI3K inhibitors. The primary outcome was progression-free survival in the full analysis set (all randomised patients) by masked central review. Safety was assessed in all patients who received at least one dose of any study drug. This study is registered with ClinicalTrials.gov, NCT02367040 and is ongoing. FINDINGS: Between Aug 3, 2015, and Dec 17, 2019, 652 patients were screened for eligibility. 307 of 458 patients were randomly assigned to copanlisib plus rituximab and 151 patients were randomly assigned to placebo plus rituximab. With a median follow-up of 19·2 months (IQR 7·4-28·8) and 205 total events, copanlisib plus rituximab showed a statistically and clinically significant improvement in progression-free survival versus placebo plus rituximab; median progression-free survival 21·5 months (95% CI 17·8-33·0) versus 13·8 months (10·2-17·5; hazard ratio 0·52 [95% CI 0·39-0·69]; p<0·0001). The most common grade 3-4 adverse events were hyperglycaemia (173 [56%] of 307 patients in the copanlisib plus rituximab group vs 12 [8%] of 146 in the placebo plus rituximab group) and hypertension (122 [40%] vs 13 [9%]). Serious treatment-emergent adverse events were reported in 145 (47%) of 307 patients receiving copanlisib plus rituximab and 27 (18%) of 146 patients receiving placebo plus rituximab. One (<1%) drug-related death (pneumonitis) occurred in the copanlisib plus rituximab group and none occurred in the placebo plus rituximab group. INTERPRETATION: Copanlisib plus rituximab improved progression-free survival in patients with relapsed indolent non-Hodgkin lymphoma compared with placebo plus rituximab. To our knowledge, copanlisib is the first PI3K inhibitor to be safely combined with rituximab and the first to show broad and superior efficacy in combination with rituximab in patients with relapsed indolent non-Hodgkin lymphoma. FUNDING: Bayer.

Vitamin C sensitizes triple negative breast cancer to PI3K inhibition therapy.

Rationale: The clinical use of PI3K inhibitors, such as buparlisib, has been plagued with toxicity at effective doses. The aim of this study is to determine if vitamin C, a potent epigenetic regulator, can improve the therapeutic outcome and reduce the dose of buparlisib in treating PIK3CA-mutated triple negative breast cancer (TNBC). Methods: The response of TNBC cells to buparlisib was assessed by EC50 measurements, apoptosis assay, clonogenic assay, and xenograft assay in mice. Molecular approaches including Western blot, immunofluorescence, RNA sequencing, and gene silencing were utilized as experimental tools. Results: Treatment with buparlisib at lower doses, along with vitamin C, induced apoptosis and inhibited the growth of TNBC cells in vitro. Vitamin C via oral delivery rendered a sub-therapeutic dose of buparlisib able to inhibit TNBC xenograft growth and to markedly block metastasis in mice. We discovered that buparlisib and vitamin C coordinately reduced histone H3K4 methylation by enhancing the nuclear translocation of demethylase, KDM5, and by serving as a cofactor to promote KDM5-mediated H3K4 demethylation. The expression of genes in the PI3K pathway, such as AKT2 and mTOR, was suppressed by vitamin C in a KDM5-dependent manner. Vitamin C and buparlisib cooperatively blocked AKT phosphorylation. Inhibition of KDM5 largely abolished the effect of vitamin C on the response of TNBC cells to buparlisib. Additionally, vitamin C and buparlisib co-treatment changed the expression of genes, including PCNA and FILIP1L, which are critical to cancer growth and metastasis. Conclusion: Vitamin C can be used to reduce the dosage of buparlisib needed to produce a therapeutic effect, which could potentially ease the dose-dependent side effects in patients.

Genomic Alterations in PIK3CA-Mutated Breast Cancer Result in mTORC1 Activation and Limit the Sensitivity to PI3Kα Inhibitors.

PI3Kα inhibitors have shown clinical activity in PIK3CA-mutated estrogen receptor-positive (ER+) patients with breast cancer. Using whole genome CRISPR/Cas9 sgRNA knockout screens, we identified and validated several negative regulators of mTORC1 whose loss confers resistance to PI3Kα inhibition. Among the top candidates were TSC1, TSC2, TBC1D7, AKT1S1, STK11, MARK2, PDE7A, DEPDC5, NPRL2, NPRL3, C12orf66, SZT2, and ITFG2. Loss of these genes invariably results in sustained mTOR signaling under pharmacologic inhibition of the PI3K-AKT pathway. Moreover, resistance could be prevented or overcome by mTOR inhibition, confirming the causative role of sustained mTOR activity in limiting the sensitivity to PI3Kα inhibition. Cumulatively, genomic alterations affecting these genes are identified in about 15% of PIK3CA-mutated breast tumors and appear to be mutually exclusive. This study improves our understanding of the role of mTOR signaling restoration in leading to resistance to PI3Kα inhibition and proposes therapeutic strategies to prevent or revert this resistance. SIGNIFICANCE: These findings show that genetic lesions of multiple negative regulators of mTORC1 could limit the efficacy of PI3Kα inhibitors in breast cancer, which may guide patient selection strategies for future clinical trials.

Phase 1 cohort expansion study of LY3023414, a dual PI3K/mTOR inhibitor, in patients with advanced mesothelioma.

BACKGROUND LY3023414 is a selective, ATP competitive inhibitor of class I PI3K isoforms, mTORC1/2 and DNA-PK. A Phase 1 dose escalation, 200 mg twice daily (BID) of LY3023414 was the determined recommended phase 2 dose (RP2D). We report the antitumor activity and safety of LY3023414 monotherapy in patients with advanced mesothelioma.METHODS Patients enrolled had advanced malignant pleural or peritoneal mesothelioma with measurable disease, ECOG PS 0-1, were refractory or ineligible to receive standard therapies. Patients received LY3023414 200 mg BID. This dose expansion cohort is intended to evaluate preliminary antitumor activity of LY3023414 by overall response rate. Safety, tolerability and pharmacokinetics were assessed. Biomarkers associated with treatment response was an exploratory endpoint. RESULTS Forty-two patients received LY3023414 for a median duration of 11.2 weeks (range: 1.1-53.0). One patient had a confirmed partial response (PR) (ORR 2.4%). Three patients had an unconfirmed PR. Seventeen patients had stable disease (SD) (DCR 43%). Most common adverse events (AEs) included fatigue (43%), nausea (43%), decreased appetite (38%), vomiting (33%), and diarrhea (29%). AEs were mostly mild or moderate. Grade ≥ 3 AEs were reported for 21% of patients with fatigue as the most frequent event (10%). Alterations of BAP1 were identified in 11/19 patients as the most common molecular aberration, followed by SETD2 and NF2 alterations. No obvious pattern of genetic changes/mutations in single genes or pathways was associated with anti-tumor activity. CONCLUSION LY3023414 monotherapy (200 mg BID) demonstrated an acceptable and manageable safety profile with limited single-agent activity in patients with advanced mesothelioma. ClinicalTrials.gov identifier: NCT01655225; Date of registration: 19 July 2012.