A phase I study of capivasertib in combination with abiraterone acetate in patients with metastatic castration-resistant prostate cancer

The Emerging Predictive and Prognostic Role of Aggressive-Variant-Associated Tumor Suppressor Genes Across Prostate Cancer Stages

Aggressive variant prostate cancer (AVPC) is characterized by a molecular signature involving combined defects in TP53, RB1, and/or PTEN (AVPC-TSGs), identifiable through immunohistochemistry or genomic analysis. The reported prevalence of AVPC-TSG alterations varies widely, reflecting differences in assay sensitivity, treatment pressure, and disease stage evolution. Although robust clinical evidence is still emerging, the study of AVPC-TSG alterations in prostate cancer (PCa) is promising. Alterations in TP53, RB1, and PTEN, as well as the combined loss of AVPC-TSGs, may have significant implications for prognosis and treatment. These biomarkers might help predict responses to various therapies, including hormonal treatments, cytotoxic agents, radiotherapy, and targeted therapies. Understanding the impact of these molecular alterations in patients with PCa is crucial for personalized management. In this review, we provide a comprehensive overview of the emerging prognostic and predictive roles of AVPC-TSG alterations across PCa stages. Moreover, we discuss the implications of different methods used for detecting AVPC-TSG alterations and summarize factors influencing their prevalence. As our comprehension of the genomic landscape of PCa disease deepens, incorporating genomic profiling into clinical decision making will become increasingly important for improving patient outcomes.

Efficacy and Safety of Combination AKT and Androgen Receptor Signaling Inhibition in Metastatic Castration-Resistant Prostate Cancer: Systematic Review and Meta-Analysis

BACKGROUND

Metastatic castration-resistant prostate cancer (mCRPC) has a poor prognosis with current treatment options including chemotherapy and androgen receptor signaling inhibitor (ARSI) medications. Poly-ADP ribose polymerase (PARP) inhibitors alone and in combination with ARSI has recently been incorporated in management for mCRPC deficient in BRCA1/2 genes. However, downregulating androgen-receptor signaling using ARSIs can upregulate the PI3K/AKT/mTOR pathway, promoting tumor cell survival. This creates a rationale for co-targeting both these pathways. This systematic review aimed to investigate AKT inhibitors and ARSI combination therapy.

METHODS

EMBASE, MEDLINE, and Scopus were searched from database inception to July 2023. Primary outcomes included objective response rate (ORR), prostate-specific antigen (PSA) response rate, adverse events (AEs), overall survival (OS), and radiographic progression-free survival (rPFS). Quality was assessed using the risk of bias tool (ROB2) and certainty of evidence with GRADE.

RESULTS

Six clinical trials with 3 Phase I, 1 Phase II, 1 Phase III were included with 771 patients and a median age ranging from 67 years to 70 years. The pooled ORR was 30% (n = 5 studies, 95% CI, 3%-84%) and PSA response rate was 43% (n = 5 studies, 95% CI, 15%-77%). The median duration of rPFS ranged from 8.2 to 19.2 months in the intervention compared with 6.4 to 16.6 months in the placebo group. A 16% reduction in radiographic progression or death was reported in patients receiving dual therapy compared with those receiving placebo. This reduction was greater by PTEN-loss status, ranging from 23% to 61%. The median OS ranged from 15.6 to 18.9 months. No significant difference was reported in survival relative to placebo. 98.8% (767/776) of patients experienced AEs of any grade, with GRADE ≥3 AEs occurring in 65.9% (512/776) of patients. The most common AE and GRADE ≥3 AEs were diarrhoea (pooled prevalence = 70%, 95% CI, 57%-81%), and hyperglycaemia (pooled prevalence = 12%, 95% CI, 6%-20%), respectively.

CONCLUSION

Combined therapy reduced the risk of rPFS, with the response higher in PTEN-loss subgroup, with a modest but not significant increase in OS. Our AE estimates showed consistency with other studies. AEs of any grade were common with the majority experiencing at least 1 AE. (PROSPERO Registration Number: CRD420202352583).

The efficacy and safety of PI3K and AKT inhibitors for patients with cancer: A systematic review and network meta-analysis

BACKGROUND

Inhibiting PI3K/AKT pathway activation may hinder the occurrence and progression of cancer. The aim of this study was to evaluate the efficacy and safety of the PI3K/AKT inhibitors and determine the most appropriate inhibitor for different cancer types.

METHODS

Electronic databases up to June 2024 were used to examine the efficacy and safety of PI3K inhibitors (alpelisib, copanlisib, duvelisib, and idelalisib) and AKT inhibitors (capivasertib, ipatasertib and MK-2206) for the treatment of cancer. Data was assessed with a random-effect pairwise and network meta-analysis. Randomized controlled trials and retrospective studies were eligible if they compared PI3K or AKT inhibitors with non-PI3K/AKT controls with no restriction.

RESULTS

The results were based on 34 studies from 34 published articles and 6 online registration trials (6710 patients). According to pairwise meta-analysis, PI3K/AKT inhibitors showed to be highly effective, especially for treating mutant cancers, but had poor safety profiles. According to our network meta-analysis, PI3K/AKT inhibitors, especially the AKT inhibitor capivasertib, are effective for treating solid cancers such as breast cancer (BC). Moreover, PI3K inhibitors, especially idelalisib, were effective for treating hematologic cancers such as chronic lymphocytic leukemia (CLL).

CONCLUSIONS

The PI3K/AKT inhibitors are effective in patients with genetic mutations. For solid cancers such as BC, capivasertib was efficacy and safety. For hematological cancers represented by CLL, idelalisib was efficacy and safety. The above studies can be used when recommending appropriate targeted therapies for patients with different cancer types.

Important Roles of PI3K/AKT Signaling Pathway and Relevant Inhibitors in Prostate Cancer Progression

Prostate cancer (PCa) is an extremely common malignant tumor of the male genitourinary system, originating from the prostate gland epithelium. Male patients are prone to relapse after treatment, which seriously threatens their health. Phosphoinositide 3-kinase (PI3K)/protein kinase B (PKB, also known as Akt) plays an important role in the growth, invasion, and metastasis of PCa. This review aimed to present an overview of the mechanism of action of the PI3K/AKT signaling pathway in PCa and discuss the application prospects of inhibitors of this pathway in treating PCa, providing a theoretical basis and reference for its clinical treatment targets.

Capivasertib

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Population Pharmacokinetics of Capivasertib in Patients with Advanced or Metastatic Solid Tumours

BACKGROUND AND OBJECTIVE

Overactivation of the PI3K/AKT pathway can occur in many cancers. Capivasertib is a potent, selective pan-AKT inhibitor. The objectives of this analysis were to develop a population pharmacokinetic model for capivasertib and to quantitatively assess the impact of intrinsic and extrinsic factors on the pharmacokinetics of capivasertib.

METHODS

Pharmacokinetic data from four phase I and II studies were combined. Capivasertib was administered orally at a dose range of 80-800 mg twice daily over 28-day and 21-day cycles as monotherapy or in combination with paclitaxel or fulvestrant, using continuous dosing or one of two intermittent dosing schedules: either 4 days on, 3 days off (4/3) or 2 days on, 5 days off (2/5). Several models and approaches were tested for their ability to describe capivasertib disposition. The covariates assessed included dose, schedule, age, body weight, race, sex, creatinine clearance, hepatic function, renal function, smoking status, food effect, formulation, and concomitant use with paclitaxel, fulvestrant, cytochrome P450, family 3, subfamily A (CYP3A) inducers, CYP3A inhibitors and acid-reducing agents.

RESULTS

A total of 3963 capivasertib plasma concentrations from 441 patients were included. Capivasertib pharmacokinetics was adequately described by a three-compartment model where the apparent clearance (CL/F) presented a moderate time-dependent and dose-dependent clearance. Following oral administration of multiple doses of capivasertib (400 mg twice daily; [4/3]), the initial CL/F was 62.2 L/h (between-subject variability 39.3%), and after approximately 120 hours, CL/F decreased by 18%. The effective half-life was 8.34 h. Steady state was predicted to be reached on every third and fourth dosing day each week from the second week with exposure levels that produced robust inhibition of AKT but not of other related kinases. The area under the plasma concentration-time curve and maximum plasma concentration of capivasertib were proportional between the dose levels of 80-480 mg after multiple doses but more than proportional beyond 480 mg. Schedule, age, race, sex, creatinine clearance, hepatic function, renal function, smoking status and concomitant use with fulvestrant, CYP3A inducers, CYP3A inhibitors or acid-reducing agents were not significant covariates for capivasertib pharmacokinetics. Concomitant use of paclitaxel, food effect and formulation statistically significantly affected capivasertib pharmacokinetics, but the effect was low. Body weight was statistically significantly related to capivasertib CL/F, with a 12% reduction in CL/F at steady state and a 14% increase in the area under the curve for 12 hours at steady state and maximum concentration at steady state at a lower body weight (47 kg vs 67 kg reference).

CONCLUSIONS

Capivasertib pharmacokinetics showed moderate between-subject variability, and most covariates assessed had no significant impact. Body weight, dose, concomitant use of paclitaxel, food effect and formulation showed statistically significant effects. However, these were predicted to impact exposure to capivasertib by  <20% and were not expected to be clinically relevant. Based on the population pharmacokinetics, no a priori dose adjustment is needed for intrinsic and extrinsic factors.

Pharmacokinetic study of capivasertib and the CYP3A4 substrate midazolam in patients with advanced solid tumors

PURPOSE

Capivasertib, a potent, selective inhibitor of all three AKT serine/threonine kinase (AKT) isoforms, is being evaluated in phase 3 trials in advanced breast and prostate cancer. This study evaluated the drug-drug interaction risk of capivasertib with the cytochrome P450 3A substrate midazolam in previously treated adults with advanced solid tumors.

METHODS

Patients received oral capivasertib 400 mg twice daily (BID) on an intermittent schedule (4 days on/3 days off) starting on day 2 of cycle 1 (29 days) and on day 1 of each 28-day cycle thereafter. In cycle 1 only, patients received oral midazolam (1 mg) on day 1 (alone), and days 8 and 12 (3rd day off and 4th day on capivasertib, respectively). Midazolam pharmacokinetics on days 8 and 12 were analyzed versus day 1. Capivasertib, with or without standard-of-care treatment, was continued in patients deemed likely to benefit. Safety and exploratory efficacy analyses were conducted.

RESULTS

Capivasertib-midazolam coadministration increased midazolam exposure (n = 21): geometric mean ratio (90% confidence interval) AUCinf and Cmax was 1.13 (0.97-1.32) and 1.15 (0.99-1.33) for day 8 versus day 1, and 1.75 (1.50-2.05) and 1.25 (1.08-1.46) for day 12 versus day 1. The capivasertib safety profile was manageable when administered with or without midazolam. Two patients had partial responses to treatment.

CONCLUSION

The up to 1.75-fold increase in midazolam exposure indicates capivasertib is a weak CYP3A inhibitor at 400 mg BID on an intermittent schedule. Capivasertib was well tolerated; exploratory efficacy analysis demonstrated evidence of clinical activity in this heavily pre-treated population.

CLINICALTRIALS

gov: NCT04958226.

Capivasertib in combination with enzalutamide for metastatic castration resistant prostate cancer after docetaxel and abiraterone: Results from the randomized phase II RE-AKT trial

BACKGROUND

PTEN loss and aberrations in PI3K/AKT signaling kinases associate with poorer response to abiraterone acetate (AA) in metastatic castration-resistant prostate cancer (mCRPC). In this study, we assessed antitumor activity of the AKT inhibitor capivasertib combined with enzalutamide in mCRPC with prior progression on AA and docetaxel.

METHODS

This double-blind, placebo-controlled, randomized phase 2 trial, recruited men ≥ 18 years with progressing mCRPC and performance status 0-2 from 15 UK centers. Randomized participants (1:1) received enzalutamide (160 mg orally, once daily) with capivasertib (400 mg)/ placebo orally, twice daily on an intermittent (4 days on, 3 days off) schedule. Primary endpoint was composite response rate (RR): RECIST 1.1 objective response, ≥ 50 % PSA decrease from baseline, or circulating tumor cell count conversion (from ≥ 5 at baseline to < 5 cells/7.5 mL). Subgroup analyses by PTENIHC status were pre-planned.

RESULTS

Overall, 100 participants were randomized (50:50); 95 were evaluable for primary endpoint (47:48); median follow-up was 43 months. RR were 9/47 (19.1 %) enzalutamide/capivasertib and 9/48 (18.8 %) enzalutamide/placebo (absolute difference 0.4 % 90 %CI -12.8 to 13.6, p = 0.58), with similar results in the PTENIHC loss subgroup. Irrespective of treatment, OS was significantly worse for PTENIHC loss (10.1 months [95 %CI: 4.6-13.9] vs 14.8 months [95 %CI: 10.8-18]; p = 0.02). Most common treatment-emergent grade ≥ 3 adverse events for the combination were diarrhea (13 % vs 2 %) and fatigue (10 % vs 6 %).

CONCLUSIONS

Combined capivasertib/enzalutamide was well tolerated but didn't significantly improve outcomes from abiraterone pre-treated mCRPC.

The emerging role of lactate in tumor microenvironment and its clinical relevance

In recent years, the significant impact of lactate in the tumor microenvironment has been greatly documented. Acting not only as an energy substance in tumor metabolism, lactate is also an imperative signaling molecule. It plays key roles in metabolic remodeling, protein lactylation, immunosuppression, drug resistance, epigenetics and tumor metastasis, which has a tight relation with cancer patients' poor prognosis. This review illustrates the roles lactate plays in different aspects of tumor progression and drug resistance. From the comprehensive effects that lactate has on tumor metabolism and tumor immunity, the therapeutic targets related to it are expected to bring new hope for cancer therapy.

Combination of navitoclax (Bcl-2 and Bcl-xL inhibitor) and Debio-0932 (Hsp90 inhibitor) suppresses the viability of prostate cancer cells via induction of apoptotic signaling pathway

Prostate cancer is one of the most common cancers in men. Given the diverse nature of prostate cancer and its tendency to respond differently to various treatments, combination therapies are often employed to enhance outcomes. In this study, the synergetic efficiency of chemotherapeutic drug Navitoclax and heat shock protein 90 (Hsp90) inhibitor Debio-0932 was evaluated in human prostate cancer cell line (PC3). Our results indicated that Navitoclax-Debio-0932 combination exhibited synergistic activity in PC3 cells at concentrations lower than IC50 values. The combination of Navitoclax and Debio-0932 decreased PC3 cell viability in a dose dependent manner at 48 h. To investigate the apoptotic potential of the Navitoclax-Debio-0932 combination against prostate cancer cells, the mRNA and protein expression levels of apoptotic and antiapoptotic markers (Bax, Bcl-2, Bcl-xL, Cyt-c, Apaf-1, Casp-3, Casp-7, and Casp-9) were measured using RT-PCR and ELISA assay. Furthermore, the cleavage activity of Casp-3 was determined by colorimetric assay. The results revealed that Navitoclax-Debio-0932 combination potently induced intrinsic apoptotic pathway in PC3 cells rather than using drugs alone. The combined treatment of Navitoclax and Debio-0932 displayed synergistic cytotoxic and apoptotic effects on prostate cancer cells, presenting a promising approach for combination therapy in prostate cancer.

Epithelial-Mesenchymal Transition: A Fundamental Cellular and Microenvironmental Process in Benign and Malignant Prostate Pathologies

Epithelial-mesenchymal transition (EMT) is a crucial and fundamental mechanism in many cellular processes, beginning with embryogenesis via tissue remodulation and wound healing, and plays a vital role in tumorigenesis and metastasis formation. EMT is a complex process that involves many transcription factors and genes that enable the tumor cell to leave the primary location, invade the basement membrane, and send metastasis to other tissues. Moreover, it may help the tumor avoid the immune system and establish radioresistance and chemoresistance. It may also change the normal microenvironment, thus promoting other key factors for tumor survival, such as hypoxia-induced factor-1 (HIF-1) and promoting neoangiogenesis. In this review, we will focus mainly on the role of EMT in benign prostate disease and especially in the process of establishment of malignant prostate tumors, their invasiveness, and aggressive behavior. We will discuss relevant study methods for EMT evaluation and possible clinical implications. We will also introduce clinical trials conducted according to CONSORT 2010 that try to harness EMT properties in the form of circulating tumor cells to predict aggressive patterns of prostate cancer. This review will provide the most up-to-date information to establish a keen understanding of the cellular and microenvironmental processes for developing novel treatment lines by modifying or blocking the pathways.

Enzyme-Responsive Branched Glycopolymer-Based Nanoassembly for Co-Delivery of Paclitaxel and Akt Inhibitor toward Synergistic Therapy of Gastric Cancer

Combined chemotherapy and targeted therapy holds immense potential in the management of advanced gastric cancer (GC). GC tissues exhibit an elevated expression level of protein kinase B (AKT), which contributes to disease progression and poor chemotherapeutic responsiveness. Inhibition of AKT expression through an AKT inhibitor, capivasertib (CAP), to enhance cytotoxicity of paclitaxel (PTX) toward GC cells is demonstrated in this study. A cathepsin B-responsive polymeric nanoparticle prodrug system is employed for co-delivery of PTX and CAP, resulting in a polymeric nano-drug BPGP@CAP. The release of PTX and CAP is triggered in an environment with overexpressed cathepsin B upon lysosomal uptake of BPGP@CAP. A synergistic therapeutic effect of PTX and CAP on killing GC cells is confirmed by in vitro and in vivo experiments. Mechanistic investigations suggested that CAP may inhibit AKT expression, leading to suppression of the phosphoinositide 3-kinase (PI3K)/AKT signaling pathway. Encouragingly, CAP can synergize with PTX to exert potent antitumor effects against GC after they are co-delivered via a polymeric drug delivery system, and this delivery system helped reduce their toxic side effects, which provides an effective therapeutic strategy for treating GC.