An Oncogenic Alteration Creates a Microenvironment that Promotes Tumor Progression by Conferring a Metabolic Advantage to Regulatory T Cells.

Only a small percentage of patients afflicted with gastric cancer (GC) respond to immune checkpoint blockade (ICB). To study the mechanisms underlying this resistance, we examined the immune landscape of GC. A subset of these tumors was characterized by high frequencies of regulatory T (Treg) cells and low numbers of effector T cells. Genomic analyses revealed that these tumors bore mutations in RHOA that are known to drive tumor progression. RHOA mutations in cancer cells activated the PI3K-AKT-mTOR signaling pathway, increasing production of free fatty acids that are more effectively consumed by Treg cells than effector T cells. RHOA mutant tumors were resistant to PD-1 blockade but responded to combination of PD-1 blockade with inhibitors of the PI3K pathway or therapies targeting Treg cells. We propose that the metabolic advantage conferred by RHOA mutations enables Treg cell accumulation within GC tumors, generating an immunosuppressive TME that underlies resistance to ICB.

A novel pan-PI3K inhibitor KTC1101 synergizes with anti-PD-1 therapy by targeting tumor suppression and immune activation.

BACKGROUND: Phosphoinositide 3-kinases (PI3Ks) are critical regulators of diverse cellular functions and have emerged as promising targets in cancer therapy. Despite significant progress, existing PI3K inhibitors encounter various challenges such as suboptimal bioavailability, potential off-target effects, restricted therapeutic indices, and cancer-acquired resistance. Hence, novel inhibitors that overcome some of these challenges are needed. Here, we describe the characterization of KTC1101, a novel pan-PI3K inhibitor that simultaneously targets tumor cell proliferation and the tumor microenvironment. Our studies demonstrate that KTC1101 significantly increases the anti-PD-1 efficacy in multiple pre-clinical mouse models. METHODS: KTC1101 was synthesized and characterized employing chemical synthesis, molecular modeling, Nuclear Magnetic Resonance (NMR), and mass spectrometry. Its target specificity was confirmed through the kinase assay, JFCR39 COMPARE analysis, and RNA-Seq analysis. Metabolic stability was verified via liver microsome and plasma assays, pharmacokinetics determined by LC-MS/MS, and safety profile established through acute toxicity assays to determine the LD50. The antiproliferative effects of KTC1101 were evaluated in a panel of cancer cell lines and further validated in diverse BALB/c nude mouse xenograft, NSG mouse xenograft and syngeneic mouse models. The KTC1101 treatment effect on the immune response was assessed through comprehensive RNA-Seq, flow cytometry, and immunohistochemistry, with molecular pathways investigated via Western blot, ELISA, and qRT-PCR. RESULTS: KTC1101 demonstrated strong inhibition of cancer cell growth in vitro and significantly impeded tumor progression in vivo. It effectively modulated the Tumor Microenvironment (TME), characterized by increased infiltration of CD8+ T cells and innate immune cells. An intermittent dosing regimen of KTC1101 enhanced these effects. Notably, KTC1101 synergized with anti-PD-1 therapy, significantly boosting antitumor immunity and extending survival in preclinical models. CONCLUSION: KTC1101's dual mechanism of action-directly inhibiting tumor cell growth and dynamically enhancing the immune response- represents a significant advancement in cancer treatment strategies. These findings support incorporating KTC1101 into future oncologic regimens to improve the efficacy of immunotherapy combinations.

Preclinical evaluation and phase 1 study of the PI3Kα/δ inhibitor TQ-B3525 in Chinese patients with advanced cancers.

BACKGROUND: Phosphatidylinositol 3-kinase (PI3K) inhibitors transformed management of various malignancies. This study preclinically characterized TQ-B3525 (dual PI3Kα/δ inhibitor) and assessed the recommended phase 2 dose (RP2D), safety, efficacy, and pharmacokinetics in relapsed or refractory (R/R) lymphoma or advanced solid tumors (STs). METHODS: Oral TQ-B3525 was given at eight dose levels on a 28-day cycle. Primary end points were dose-limiting toxicity (DLT), maximum tolerated dose (MTD), and safety. RESULTS: TQ-B3525 showed high selectivity and suppressed tumor growth. Between June 12, 2018, and November 18, 2020, 80 patients were enrolled (63 in dose-escalation cohort; 17 in dose-expansion cohort). Two DLTs occurred in two (two of 63, 3.2%) DLT-evaluable patients; MTD was not identified. TQ-B3525 at 20 mg once daily was selected as RP2D. Grade 3 or worse treatment-related adverse events mainly included hyperglycemia (16.3%), neutrophil count decreased (15.0%), and diarrhea (10.0%). Two (2.5%) treatment-related deaths were reported. Sixty patients with R/R lymphoma and 11 advanced STs demonstrated objective response rates of 68.3% and 9.1%, disease control rates of 91.7% and 54.6%, median progression-free survivals of 12.1 and 1.1 months; median overall survivals were not reached. CONCLUSION: TQ-B3525 exhibited rapid absorption and a nearly proportional increase in exposure. Acceptable safety and promising efficacy support further investigation of TQ-B3525 (20 mg once daily) for R/R lymphoma.

Real-world treatment patterns and clinical outcomes in patients treated with eribulin after prior phosphoinositide 3-Kinase inhibitor treatment for metastatic breast cancer.

PURPOSE: In 2010, the US Food and Drug Administration approved eribulin for the treatment of metastatic breast cancer (MBC). Since then, the treatment landscape has evolved with many new therapy classes, a more recent one being the small molecule inhibitors of phosphoinositide 3 kinase (PI3K). We sought to characterize the treatment patterns and clinical outcomes of patients with MBC who received eribulin following prior treatment with a PI3K inhibitor. METHODS: A retrospective cohort study based on medical record review included MBC patients who initiated eribulin between March 2019 and September 2020 following prior treatment with a PI3K inhibitor was conducted. Patient demographics, treatment characteristics, and clinical outcomes were analyzed descriptively. Real-world progression-free survival (rwPFS) and overall survival (OS) were estimated from the initiation of eribulin therapy using Kaplan-Meier analyses. RESULTS: 82 eligible patients were included. Patients' median age at eribulin initiation was 62 years; 86.5% had hormone receptor-positive, human epidermal growth factor receptor 2-negative tumors. Eribulin was most often administered in the second or third line (82.9%) in the metastatic setting. Best overall response on eribulin was reported as complete or partial response in 72% of the patients. The median rwPFS was 18.9 months (95% confidence interval [CI], 12.4-not estimable); median OS was not reached. The estimated rwPFS and OS rates at 12 months were 63.3% (95% CI, 50.5-73.7) and 82.6% (95% CI, 72.4-89.3), respectively. CONCLUSION: Our real-world study suggests that eribulin may be a potential treatment option for MBC patients who fail a prior PI3K inhibitor.

Preclinical characterization of the absorption and disposition of the brain penetrant PI3K/mTOR inhibitor paxalisib and prediction of its pharmacokinetics and efficacy in human.

Glioblastoma multiforme (GBM) is the most common primary brain tumour in adults. Available treatments have not markedly improved patient survival in the last twenty years. However, genomic investigations have showed that the PI3K pathway is frequently altered in this glioma, making it a potential therapeutic target.Paxalisib is a brain penetrant PI3K/mTOR inhibitor (mouse Kp,uu 0.31) specifically developed for the treatment of GBM. We characterised the preclinical pharmacokinetics and efficacy of paxalisib and predicted its pharmacokinetics and efficacious dose in humans.Plasma protein binding of paxalisib was low, with the fraction unbound ranging from 0.25 to 0.43 across species. The hepatic clearance of paxalisib was predicted to be low in mice, rats, dogs and humans, and high in monkeys, from hepatocytes incubations. The plasma clearance was low in mice, moderate in rats and high in dogs and monkeys. Oral bioavailability ranged from 6% in monkeys to 76% in rats.The parameters estimated from the pharmacokinetic/pharmacodynamic modelling of the efficacy in the subcutaneous U87 xenograft model combined with the human pharmacokinetics profile predicted by PBPK modelling suggested that a dose of 56 mg may be efficacious in humans. Paxalisib is currently tested in Phase III clinical trials.

Antitumor activity of the PI3K δ-sparing inhibitor MEN1611 in PIK3CA mutated, trastuzumab-resistant HER2 + breast cancer.

PURPOSE: Dysregulation of the PI3K pathway is one of the most common events in breast cancer. Here we investigate the activity of the PI3K inhibitor MEN1611 at both molecular and phenotypic levels by dissecting and comparing its profile and efficacy in HER2 + breast cancer models with other PI3K inhibitors. METHODS: Models with different genetic backgrounds were used to investigate the pharmacological profile of MEN1611 against other PI3K inhibitors. In vitro studies evaluated cell viability, PI3K signaling, and cell death upon treatment with MEN1611. In vivo efficacy of the compound was investigated in cell line- and patient-derived xenografts models. RESULTS: Consistent with its biochemical selectivity, MEN1611 demonstrated lower cytotoxic activity in a p110δ-driven cellular model when compared to taselisib, and higher cytotoxic activity in the p110ß-driven cellular model when compared to alpelisib. Moreover, MEN1611 selectively decreased the p110α protein levels in PIK3CA mutated breast cancer cells in a concentration- and proteasome-dependent manner. In vivo, MEN1611 monotherapy showed significant and durable antitumor activity in several trastuzumab-resistant PIK3CA-mutant HER2 + PDX models. The combination of trastuzumab and MEN1611 significantly improved the efficacy compared to single agent treatment. CONCLUSIONS: The profile of MEN1611 and its antitumoral activity suggest an improved profile as compared to pan-inhibitors, which are limited by a less than ideal safety profile, and isoform selective molecules, which may potentially promote development of resistance mechanisms. The compelling antitumor activity in combination with trastuzumab in HER2 + trastuzumab-resistant, PIK3CA mutated breast cancer models is at the basis of the ongoing B-Precise clinical trial (NCT03767335).

Design, synthesis and antitumor effects of novel benzimidazole derivatives as PI3K inhibitors.

Blocking the PI3K/Akt pathway has been widely recognized as an attractive cancer therapeutic strategy because of its crucial role in cell growth and survival. This study presents the synthesis of 24 new 5-Methoxy-6-substituted-1H-benzimidazole derivatives (4a-4x) and the evaluation of their anti-proliferative activities against A549, Siha, MCF-7, HepG2, PC3, and HCT-116 tumor cell lines through MTT assay. Compound 4w exhibited superior anti-tumor activity against the A549 cells with IC50 values of 1.55 ± 0.18 µM, and better than the BKM120 (IC50 = 9.75 ± 1.25 µM). Further studies indicated that 4w could induce G0/G1 phase arrest, cell apoptosis, and down-regulate expression of p-PI3K and p-Akt. These results indicate that 4w could be served as a lead compound of PI3K inhibitor for the treatment of human lung cancers.

Current Treatment Options in Relapsed and Refractory Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma: a Review.

OPINION STATEMENT: Treatment of relapsed and refractory (R/R) chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL) has changed dramatically over the past decade due to the development of oral targeted agents in several therapeutic classes, including BTK inhibitors (such as ibrutinib, acalabrutinib, zanubrutinib, and the non-covalent BTK inhibitor pirtobrutinib), the first in class BCL2 inhibitor venetoclax, PI3K inhibitors (idelalisib and duvelisib), and monoclonal antibodies in monotherapy and in combination. My approach to treatment of the R/R patient draws heavily on prior therapies, such that a patient with no exposure to prior novel therapies would be offered either a BTK or BCL2-based regimen, whereas patients with prior BTK inhibitor exposure would likely receive a BCL2 inhibitor and vice versa. For patients who are intolerant to a BTK inhibitor but are otherwise responding, an alternate BTK inhibitor may be considered. For those patients who have received a fixed-duration BCL2 inhibitor-based regimen and have maintained a response for greater than 12-24 months, re-treatment with a BCL2 inhibitor-based regimen at progression may be considered based on limited data, recognizing that robust prospective clinical trials are lacking in this space. For those patients who are "double refractory" and have progressed on both a BTK inhibitor and a BCL2 inhibitor-based regimen, clinical trials are strongly preferred. In absence of a clinical trial, these patients can be challenged with PI3K inhibitors, though responses are usually not durable, and toxicity is high. Combination cytotoxic chemotherapy with novel agents, allogeneic hematopoietic stem cell transplant, and cellular therapy may be considered for very high-risk populations, such as patients with Richter's transformation, though novel approaches are urgently needed and clinical trial enrollment is highly encouraged.

Anti-cancer effect of palmatine through inhibition of the PI3K/AKT pathway in canine mammary gland tumor CMT-U27 cells.

Canine mammary gland tumors (CMTs) are the most common and lethal cancers in female dogs. Dysregulated phosphoinositide 3-kinases (PI3K)/AKT pathway reportedly was involved in the growth and metastasis of CMTs. However, there are few studies on therapeutic strategies for targeting the PI3K pathway in CMTs. In this study, we aimed to determine whether palmatine, a natural isoquinoline alkaloid with anti-cancer properties, could inhibit the growth of CMTs and whether the inhibitory effect was mediated through the PI3K/AKT pathway. Our in vitro experiments on CMT-U27, a CMT cell line, showed that palmatine reduced cell proliferation and induced cell death. Western blotting results revealed that palmatine decreased the protein expression of PI3K, PTEN, AKT, and mechanistic target of rapamycin in the PI3K/AKT pathway, which was supported by the results of immunocytochemistry. Additionally, palmatine suppressed the migration and tube formation of canine aortic endothelial cells as well as the migration of CMT U27 cells. Our in vivo results showed that palmatine inhibited tumor growth in a CMT-U27 mouse xenograft model. We observed a decreased expression of proteins in the PI3K/AKT pathway in tumor tissues, similar to the in vitro results. Furthermore, palmatine significantly disrupted the tumor vasculature and inhibited metastasis to adjacent lymph nodes. In conclusion, our findings demonstrate that palmatine exerts anti-cancer effects against CMTs by inhibiting PI3K/AKT signaling pathway, suggesting that palmatine has potential as a canine-specific PI3K inhibitor for the treatment of CMTs.

The Attenuation of Insulin/IGF-1 Signaling Pathway Plays a Crucial Role in the Myo-Inositol-Alleviated Aging in Caenorhabditis elegans.

Myo-Inositol (MI) has been shown to alleviate aging in Caenorhabditis (C). elegans. However, the mechanism by which MI alleviates aging remains unclear. In this study, we investigate whether MI can modulate the PI3K so as to attenuate the insulin/IGF-1 signaling (IIS) pathway and exert the longevity effect. The wild-type C. elegans and two mutants of AKT-1 and DAF-16 were used to explore the mechanism of MI so as to extend the lifespan, as well as to improve the health indexes of pharyngeal pumping and body bend, and an aging marker of autofluorescence in the C. elegans. We confirmed that MI could significantly extend the lifespan of C. elegans. MI also ameliorated the pharyngeal pumping and body bend and decreased autofluorescence. We further adopted the approach to reveal the loss-of-function mutants to find the signaling mechanism of MI. The functions of the lifespan-extending, health-improving, and autofluorescence-decreasing effects of MI disappeared in the AKT-1 and DAF-16 mutants. MI could also induce the nuclear localization of the DAF-16. Importantly, we found that MI could dramatically inhibit the phosphoinositide 3-kinase (PI3K) activity in a dose-dependent manner with an IC50 of 90.2 µM for the p110α isoform of the PI3K and 21.7 µM for the p110ß. In addition, the downregulation of the PI3K expression and the inhibition of the AKT phosphorylation by MI was also obtained. All these results demonstrate that MI can inhibit the PI3K activity and downregulate the PI3K expression, and the attenuation of the IIS pathway plays a crucial role for MI in alleviating aging in C. elegans.

Discovery of a novel photoswitchable PI3K inhibitor toward optically-controlled anticancer activity.

Light has been used increasingly as an external stimulus in drug design. Herein, we report a novel photoswitchable azo-PI3K inhibitor, which bears an azobenzene moiety and can be efficiently converted between trans and cis configuration with changes of anticancer activity upon different light irradiation. Its photochemical properties were characterized by UV, LC-MS and NMR techniques. In biological assessment, trans and cis isomers of the azo-PI3K inhibitor exhibited differential anticancer activity in inhibition of PI3K pathway, cell migratory ability, and colony formation and can be switched at a cellular level upon light irradiation. Moreover, both isomers of the azo-PI3K inhibitor significantly inhibited tumor growth in a zebrafish xenograft model. Together, this photoswitchable azo-PI3K inhibitor may be useful as a valuable tool compound for studying the PI3K pathway and further optimization toward optically-controlled anticancer activity.

Metformin resistant MDA-MB-468 cells exhibit EMT-like phenotype and increased migration capacity.

PURPOSE: Metformin is one of the most prescribed drugs for the treatment of type II diabetes. Its anti-proliferative effect is also taken advantage for the treatment of cancer. Despite many of the studies mentioning the positive effects of metformin in inhibiting the proliferation of cancer cells, there are also studies which questions this idea as well. METHODS: In this study, we investigated the most widely studied breast cancer cell lines, ER (+) MCF7 cells, TNBC MDA-MB-231 and MDA-MB-468 cells in terms of metastatic behavior under long-term metformin treatment. MCF7, MDA-MB-231 and MDA-MB-468 cells were gained resistant to metformin starting from 0.2 to 3.2 mM. RESULTS: Compared to MCF7 and MDA-MB-231 cell lines, we only observed dramatic changes in MDA-MB-468 cells whose morphology has been changed towards mesenchymal like phenotype. Moreover, migration capacity of these cells was also significantly increased which were validated at both mRNA and protein levels as well as wound healing assay. In addition to EMT like phenotype and increasing migration capacity of metformin resistant MDA-MB-468 cells, they exhibited less sensitivity to PI3K inhibitor. CONCLUSIONS: All together, our data pointed out that, metformin's effects should be questioned depending on the subtype of the breast cancer that's to be treated.

EPIK-O/ENGOT-OV61: alpelisib plus olaparib vs cytotoxic chemotherapy in high-grade serous ovarian cancer (phase III study).

Patients with platinum-resistant or -refractory high-grade serous ovarian cancer (HGSOC) have a poor prognosis, and their management represents a substantial unmet medical need. Preclinical data and results from a phase Ib trial demonstrated the efficacy and tolerability of the combination of the α-specific phosphatidylinositol-3-kinase (PI3K) inhibitor alpelisib plus the poly(adenosine diphosphate-ribose) polymerase (PARP) inhibitor olaparib in platinum-resistant, non-BRCA-mutated ovarian cancer. Here, we describe the study design and rationale for the phase III, multicenter, open-label, randomized, active-controlled EPIK-O/ENGOT-OV61 trial investigating alpelisib in combination with olaparib compared with standard-of-care chemotherapy in patients with platinum-resistant or -refractory HGSOC with no germline BRCA mutation. Progression-free survival (blinded independent review committee) is the primary end point. Overall survival is a key secondary end point. Clinical Trial Registration:: NCT04729387 (ClinicalTrials.gov).

Design, synthesis and bioactivities evaluation of novel oleanolic acid derivatives as potent PI3K inhibitors.

Oleanolic acid has previously been shown to possess PI3K inhibitory activity, thus, the purpose of this work was to generate a series of derivatives that improve the potency. Twenty rationally designed oleanolic acid derivatives were synthesized and tested the cytotoxicity and PI3K inhibitory activity. The results suggested that attachment of additional structural elements such as association of thiazole group to A ring and insertion of phenylurea group was important for increasing activities. The most active derivative was compound II2, which exhibited PI3K inhibitory activity (IC50 = 58.42 nmol/l) and improved interaction with activity site of PI3K according with docking studies.

Combined Treatment with PI3K Inhibitors BYL-719 and CAL-101 Is a Promising Antiproliferative Strategy in Human Rhabdomyosarcoma Cells.

Rhabdomyosarcoma (RMS) is a highly malignant and metastatic pediatric cancer arising from skeletal muscle myogenic progenitors. Recent studies have shown an important role for AKT signaling in RMS progression. Aberrant activation of the PI3K/AKT axis is one of the most frequent events occurring in human cancers and serves to disconnect the control of cell growth, survival, and metabolism from exogenous growth stimuli. In the study reported here, a panel of five compounds targeting the catalytic subunits of the four class I PI3K isoforms (p110α, BYL-719 inhibitor; p110ß, TGX-221 inhibitor; p110γ, CZC24832; p110δ, CAL-101 inhibitor) and the dual p110α/p110δ, AZD8835 inhibitor, were tested on the RMS cell lines RD, A204, and SJCRH30. Cytotoxicity, cell cycle, apoptosis, and the activation of downstream targets were analyzed. Of the individual inhibitors, BYL-719 demonstrated the most anti-tumorgenic properties. BYL-719 treatment resulted in G1/G0 phase cell cycle arrest and apoptosis. When combined with CAL-101, BYL-719 decreased cell viability and induced apoptosis in a synergistic manner, equaling or surpassing results achieved with AZD8835. In conclusion, our findings indicate that BYL-719, either alone or in combination with the p110δ inhibitor, CAL-101, could represent an efficient treatment for human rhabdomyosarcoma presenting with aberrant upregulation of the PI3K signaling pathway.

[Expert consensus on the clinical application of PI3K/AKT/mTOR inhibitors in the treatment of advanced breast cancer].

Phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway (PAM pathway) plays an important role in the development of breast cancer and are closely associated with the resistance to endocrine therapy in advanced breast cancer. Therefore, anti-cancer treatment targeting key molecules in this signaling pathway has become research hot-spot in recent years. Randomized clinical trials have demonstrated that PI3K/AKT/mTOR inhibitors bring significant clinical benefit to patients with advanced breast cancer, especially to those with hormone receptor (HR)-positive, human epidermal growth factor receptor (HER) 2-negative advanced breast cancer. Alpelisib, a PI3K inhibitor, and everolimus, an mTOR inhibitor, have been approved by Food and Drug Administration. Based on their high efficacy and relatively good safety profile, expanded indication of everolimus in breast cancer have been approved by National Medical Products Administration. Alpelisib is expected to be approved in China in the near future. The members of the consensus expert panel reached this consensus to comprehensively define the role of PI3K/AKT/mTOR signaling pathway in breast cancer, efficacy and clinical applications of PI3K/AKT/mTOR inhibitors, management of adverse reactions, and PIK3CA mutation detection, in order to promote the understanding of PI3K/AKT/mTOR inhibitors for Chinese oncologists, improve clinical decision-making, and prolong the survival of target patient population.

Targeting the mutant PIK3CA gene by DNA-alkylating pyrrole-imidazole polyamide in cervical cancer.

PIK3CA is the most frequently mutated oncogene in cervical cancer, and somatic mutations in the PIK3CA gene result in increased activity of PI3K. In cervical cancer, the E545K mutation in PIK3CA leads to elevated cell proliferation and reduced apoptosis. In the present study, we designed and synthesized a novel pyrrole-imidazole polyamide-seco-CBI conjugate, P3AE5K, to target the PIK3CA gene bearing the E545K mutation, rendered possible by nuclear access and the unique sequence specificity of pyrrole-imidazole polyamides. P3AE5K interacted with double-stranded DNA of the coding region containing the E545K mutation. When compared with conventional PI3K inhibitors, P3AE5K demonstrated strong cytotoxicity in E545K-positive cervical cancer cells at lower concentrations. PIK3CA mutant cells exposed to P3AE5K exhibited reduced expression levels of PIK3CA mRNA and protein, and subsequent apoptotic cell death. Moreover, P3AE5K significantly decreased the tumor growth in mouse xenograft models derived from PIK3CA mutant cells. Overall, the present data strongly suggest that the alkylating pyrrole-imidazole polyamide P3AE5K should be a promising new drug candidate targeting a constitutively activating mutation of PIK3CA in cervical cancer.

LPIN1 downregulation enhances anticancer activity of the novel HDAC/PI3K dual inhibitor FK-A11.

Phosphatidylinositol-3 kinase (PI3K) inhibitor and histone deacetylase (HDAC) inhibitor have been developed as potential anticancer drugs. However, the cytotoxicity of PI3K inhibitor or HDAC inhibitor alone is relatively weak. We recently developed a novel HDAC/PI3K dual inhibitor FK-A11 and confirmed its enhanced cytotoxicity when compared to that of PI3K inhibitor or HDAC inhibitor alone on several cancer cell lines. However, the in vivo antitumor activity of FK-A11 was insufficient. We conducted high-throughput RNA interfering screening and identified gene LPIN1 which enhances the cytotoxicity of FK-A11. Downregulation of LPIN1 enhanced simultaneous inhibition of HDAC and PI3K by FK-A11 and enhanced the cytotoxicity of FK-A11. Propranolol, a beta-adrenoreceptor which is also a LPIN1 inhibitor, enhanced the in vitro and in vivo cytotoxicity and antitumor effect of FK-A11. These findings should help in the development of FK-A11 as a novel HDAC/PI3K dual inhibitor.

A phase II study of the PI3K inhibitor copanlisib in combination with the anti-CD20 monoclonal antibody rituximab for patients with marginal zone lymphoma: treatment rationale and protocol design of the COUP-1 trial.

BACKGROUND: Advanced stage marginal zone lymphoma (MZL) is an incurable indolent B-cell lymphoma, for which a wide variety of treatments ranging from single agent rituximab to more dose intense immunochemotherapy exists. One of the major goals in this palliative setting is to develop chemotherapy-free treatments, which approach the efficacy of immunochemotherapies, but avoid chemotherapy associated toxicity in this often elderly patient population. The PI3K inhibitor copanlisib has recently shown remarkable clinical activity in refractory or relapsed indolent B-cell lymphomas, among them MZL. Based on these data, copanlisib monotherapy was granted breakthrough designation by the FDA for the treatment of adult patients with relapsed marginal zone lymphoma who have received at least two prior therapies. However, data are still limited in particular for MZL. Based on this, the COUP-1 trial aims at testing the toxicity and efficacy of copanlisib in combination with rituximab in treatment naive and relapsed MZL. METHODS: COUP-1 is a prospective, multicenter, single-arm, open-label, non-randomized phase II trial of 6 cycles (28 days cycle) of copanlisib (60 mg intravenous day 1, 8, 15) and rituximab (375 mg/m2 intravenous day 1) in the induction phase followed by a maintenance phase of copanlisib (d1, d15 every 4 weeks for a maximum of 12 cycles) and rituximab (d1 every 8 weeks for a maximum of 12 cycles) in patients aged ≥18 years with previously untreated or relapsed MZL in need of treatment. A total of 56 patients are to be enrolled. Primary endpoint is the complete response (CR) rate determined 12 months after start of induction therapy. Secondary endpoints include the overall response (OR) rate, progression free survival (PFS), overall survival (OS), safety and patient related outcome with quality of life. The study includes a translational bio-sampling program with the prospect to measure minimal residual disease. The study was initiated in November 2019. DISCUSSION: The COUP-1 trial evaluates the efficacy and toxicity of the treatment of copanlisib in combination with rituximab in patients with MZL and additionally offers the chance for translational research in this heterogenous type of lymphoma. TRIAL REGISTRATION: ClinicalTrials.gov : NCT03474744 . Registration date: 03/23/2018.

Discovery of cinnoline derivatives as potent PI3K inhibitors with antiproliferative activity.

Cinnoline is a potential pharmacophore which has rarely been reported for uses as PI3K inhibitors. In this study, a series of cinnoline derivatives were developed as PI3K inhibitors and evaluated for enzymatic and cellular activities. Most compounds displayed nanomolar inhibitory activities against PI3Ks, among which 25 displayed high LLE and micromolar inhibitory potency against three human tumor cell lines (IC50 = 0.264 µM, 2.04 µM, 1.14 µM).