Combination Of RAD001 Research Articles

Bone-Targeting Radionuclides in the Treatment of Metastatic Castration-Resistant Prostate Cancer: A Review on Radium-223 Chloride (Alpharadin) in Combination with Other Therapies

Recent advances have broadened the range of therapeutic options for mCRPC, with several new treatments, including novel hormonal therapies (enzalutamide, abiraterone), chemotherapeutic agents (docetaxel, cabazitaxel), immunotherapies (sipuleucel-T), and bone targeting radiopharmaceuticals (radium-223) showing improved clinical outcomes and receiving U.S. Food and Drug Administration approval. These new treatments provide new avenues for improving patient survival and quality of life. Radium-223, a targeted alpha-emitter, specifically targets bone metastases, offering palliative benefits and a potential increase in life expectancy. The integration of radium-223 with other treatments shows promise for managing mCRPC. However, the optimal sequencing and combination of radium-223 with other therapies are still being explored, with various clinical trials investigating new therapeutic approaches. The integration of these therapies, especially to provide more effective, personalized treatment strategies, requires further investigation. A thorough literature review was conducted on current treatments for mCRPC, including chemotherapeutic agents, oral hormonal therapies targeting the androgen receptor axis, immunotherapies, and radium-223. Ongoing clinical trials investigating radium-233 in the context of other therapies for the treatment of mCRPC patients were also reviewed. Further studies should focus on determining the optimal sequencing and dosing and identifying biomarkers that predict treatment response to enhance outcomes of mCRPC patients. This review underlines the rational strategies of combining radium-223 with other therapies, investigating their impact on bone in terms of delaying skeletal-related events, and managing bone disease progression in mCRPC patients.

LBA1 A randomized multicenter open label phase III trial comparing enzalutamide vs a combination of Radium-223 (Ra223) and enzalutamide in asymptomatic or mildly symptomatic patients with bone metastatic castration-resistant prostate cancer (mCRPC): First results of EORTC-GUCG 1333/PEACE-3

LBA1 A randomized multicenter open label phase III trial comparing enzalutamide vs a combination of Radium-223 (Ra223) and enzalutamide in asymptomatic or mildly symptomatic patients with bone metastatic castration-resistant prostate cancer (mCRPC): First results of EORTC-GUCG 1333/PEACE-3

Abstract 688: Radium-223 in combination with darolutamide exhibits synergistic antitumor efficacy in LNCaP prostate cancer models

Abstract Radium-223 dichloride (radium-223) is a targeted alpha therapy that binds to newly formed abnormal bone in bone metastases and induces DNA double-strand breaks (DSBs) in cancer cells, osteoblasts and osteoclasts. Radium-223 is used for the treatment of patients with metastatic castration-resistant prostate cancer (mCRPC). Darolutamide is an androgen receptor inhibitor indicated for patients with metastatic hormone-sensitive prostate cancer or non-metastatic CRPC. We studied the antitumor effects of radium-223 in combination with darolutamide using LNCaP human prostate cancer cells in vitro and an intratibial LNCaP model mimicking prostate cancer metastasized to bone. The in vitro antiproliferative effects of radium-223 and darolutamide were determined using LNCaP cells. Gene set enrichment analysis (GSEA) was conducted on RNA sequencing data from LNCaP cells treated with the synthetic androgen R1881 alone or in combination with darolutamide. LNCaP cells were inoculated into the right tibia of male NOD.scid mice. The mice (n=7-9/group) were randomized based on serum prostate-specific antigen (PSA) and treated with vehicle, radium-223 (330 kBq/kg, Q4Wx2, i.v.), darolutamide (100 mg/kg, BID, p.o.), or with a combination of radium-223 and darolutamide, for 41 days. PSA and the bone turnover markers PINP and CTX-I were measured every second week in serum. Tumor-induced abnormal bone area, bone formation rate and radium-223 uptake in tumor-bearing tibiae were determined by X-ray, histomorphometry and gamma counter, respectively. The combination of radium-223 and darolutamide showed synergistic antiproliferative effects with combination indexes between 0.69-0.75 in vitro. GSEA demonstrated a prominent darolutamide-induced downregulation of DNA damage response (DDR) signaling pathways. In vivo, the combination treatment showed synergistic antitumor efficacy (p=0.04) as demonstrated by lower PSA concentrations when compared with the vehicle, radium-223 or darolutamide monotherapies (p=0.004, p=0.011 and p=0.002, respectively). In the vehicle and combination treatment groups, the mean serum PSA was 541% and 95.9% of the pre-treatment level, respectively. Furthermore, radium-223 alone or in combination with darolutamide inhibited increased bone turnover, tumor-induced abnormal bone growth and trabecular bone formation when compared to vehicle. Concurrent administration of darolutamide did not affect radium-223 uptake in tibiae. Radium-223 in combination with darolutamide exhibited synergistic antitumor efficacy both in vitro and in vivo. The synergistic effects could be due to the radiosensitization of cancer cells by darolutamide-induced downregulation of DDR pathways. Our results suggest that the combination of targeted alpha therapy with an androgen receptor inhibitor is a promising treatment strategy for mCRPC. Citation Format: Christoph A. Schatz, Mari I. Suominen, Andreas Schlicker, Matias Knuuttila, Esa Alhoniemi, Sanna-Maria Käkönen, Bernard Haendler, Urs B. Hagemann, Arne Scholz. Radium-223 in combination with darolutamide exhibits synergistic antitumor efficacy in LNCaP prostate cancer models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 688.

Zoledronic Acid Prevents Bone Resorption Caused by the Combination of Radium-223, Abiraterone Acetate, and Prednisone in an Intratibial Prostate Cancer Mouse Model.

An increased risk of non-pathological fractures in patients with prostate cancer and bone metastases has been associated with combination treatment with radium-223, abiraterone, and prednisone/prednisolone in the absence of bone-protecting agents. Here, we investigated possible mechanisms leading to this outcome using an intratibial LNCaP model mimicking prostate cancer bone metastases. Male NOD.scid mice were inoculated intratibially with LNCaP prostate cancer cells and treated with vehicle, radium-223, abiraterone, prednisone, zoledronic acid, or their combinations for 28 days. Serum TRACP 5b and PSA levels were measured. Bone structure, quality, and formation rate of non-tumor-bearing and tumor-bearing tibiae were analyzed by microCT, 3-point bending assay, and dynamic histomorphometry, respectively. Radium-223 incorporation into bone was also measured. Radium-223/abiraterone/prednisone combination treatment induced a transient increase in bone resorption indicated by elevated TRACP 5b levels, which was inhibited by concurrent treatment with zoledronic acid. Furthermore, radium-223/abiraterone/prednisone combination reduced periosteal and trabecular new bone formation and the number of osteoblasts, but bone structure or biomechanical quality were not affected. The abiraterone/prednisone treatment decreased radium-223 incorporation into tumor-bearing bone, possibly explaining the lack of additional antitumor efficacy. In conclusion, radium-223/abiraterone/prednisone combination increased bone resorption, which may have been one of the mechanisms leading to an increased fracture risk in patients with mCRPC.

Enhanced Antitumor Efficacy of Radium-223 and Enzalutamide in the Intratibial LNCaP Prostate Cancer Model.

Radium-223 dichloride and enzalutamide are indicated for metastatic castration-resistant prostate cancer and their combination is currently being investigated in a large phase 3 clinical trial. Here, we evaluated the antitumor efficacy of radium-223, enzalutamide, and their combination in the intratibial LNCaP model mimicking prostate cancer metastasized to bone. In vitro experiments revealed that the combination of radium-223 and enzalutamide inhibited LNCaP cell proliferation and showed synergistic efficacy. The combination of radium-223 and enzalutamide also demonstrated enhanced in vivo antitumor efficacy, as determined by measuring serum PSA levels in the intratibial LNCaP model. A decreasing trend in the total area of tumor-induced abnormal bone was associated with the combination treatment. The serum levels of the bone formation marker PINP and the bone resorption marker CTX-I were lowest in the combination treatment group and markedly decreased compared with vehicle group. Concurrent administration of enzalutamide did not impair radium-223 uptake in tumor-bearing bone or the ability of radium-223 to inhibit tumor-induced abnormal bone formation. In conclusion, combination treatment with radium-223 and enzalutamide demonstrated enhanced antitumor efficacy without compromising the integrity of healthy bone. The results support the ongoing phase 3 trial of this combination.

AlphaBet: Combination of Radium-223 and [17 7Lu]Lu-PSMA-I&T in men with metastatic castration-resistant prostate cancer (clinical trial protocol).

[177Lu]Lu-PSMA is a radioligand therapy used in metastatic castration-resistant prostate cancer (mCRPC). Despite a survival benefit, the responses for many patients receiving [177Lu]Lu-PSMA are not durable, and all patients eventually develop progressive disease. The bone marrow is the most common site of progression. Micrometastases in this area likely receive an inadequate dose of radiation, as the emitted beta-particles from 177Lu travel an average range of 0.7 mm in soft tissue, well beyond the diameter of micrometastases. Radium-223 (223Ra) is a calcium-mimetic and alpha-emitting radionuclide approved for use in men with mCRPC with bone metastases. The range of emitted alpha particles in soft tissue is much shorter (≤100 μm) with high linear energy transfer, likely more lethal for osseous micrometastases. We anticipate that combining a bone-specific alpha-emitter with [177Lu]Lu-PSMA will improve eradication of micrometastatic osseous disease, and thereby lead to higher and longer responses. This is a single-center, single-arm phase I/II trial evaluating the combination of 223Ra and [177Lu]Lu-PSMA-I&T in men with mCRPC. Thirty-six patients will receive 7.4 GBq of [177Lu]Lu-PSMA-I&T, concurrently with 223Ra in escalating doses (28 kBq/kg - 55kBq/kg), both given intravenously every six weeks for up to six cycles. Eligible patients will have at least two untreated bone metastases visible on bone scintigraphy, and PSMA-positive disease on PSMA PET scan. Patients must have adequate bone marrow and organ function and be willing to undergo tumor biopsies. Patients with discordant disease visible on FDG PET scan (defined as FDG positive disease with minimal or no PSMA expression and no uptake on bone scan) will be excluded. Other key exclusion criteria include the presence of diffuse marrow disease, prior treatment with 223Ra or [177Lu]Lu-PSMA, or more than one prior line of chemotherapy for prostate cancer. The co-primary objectives of this study are to determine the maximum tolerated dose of 223Ra when combined with [177Lu]Lu-PSMA-I&T and the 50% PSA response rate. The AlphaBet trial is a phase I/II study combining 223Ra with [177Lu]Lu-PSMA-I&T in patients with mCRPC. We aim to enroll the first patient in Q3 2022, and recruitment is anticipated to continue for 24 months. NCT05383079.

Synergistic anticancer effects of everolimus (RAD001) and Rhein on gastric cancer cells via phosphoinositide-3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway

ABSTRACT Everolimus (RAD001) is a mTOR inhibitor and is widely used for the treatment of gastric cancer (GC). Evidence suggests that Rhein has anticancer effect on GC. But the synergistic effect and mechanism of RAD001 and Rhein combination on GC is not clear. The current study aims to clarify the combination of RAD001 and Rhein in GC treatment. We found Rhein dose-dependently repressed MGC-803 cell viability (50% inhibition concentration (IC50) value = 94.26 μM). Rhein (80 μM) significantly suppressed GC cell proliferation and invasion. RAD001 dose-dependently repressed MGC-803 cells viability (IC50 value = 45.41 nM). The combination of Rhein and RAD001 repressed MGC-803 cells viability, invasion, and proliferation compared to the administration of Rhein or RAD001 alone. Protein levels of epithelial-mesenchymal transition (EMT)-related molecules E-cadherin, N-cadherin and Vimentin expressions were significantly affected by the combination of Rhein and RAD001. The combination of Rhein and RAD001 significantly facilitated cell apoptosis and up-regulated expressions of cell apoptosis and cycle-related protein p53, cyclin-dependent kinase 4 (CDK4) and cyclin D1 compared to the administration of Rhein or RAD001 alone. Moreover, the combination of Rhein and RAD001 repressed the expressions of phosphorylation-phosphoinositide-3-kinase (p-PI3K), p-protein kinase B (p-AKT) and p-mammalian target of rapamycin (p-mTOR). Finally, the combination of RAD001 and Rhein significantly decreased tumor weight and volume, suppressed the expressions of p-PI3K, p-Akt and p-mTOR, and repressed cell proliferation marker Ki-67 expression, which exerted synergistic cancer prevention in GC in vivo. Overall, the combination of Rhein and RAD001 exert synergistic cancer prevention in GC via PI3K/Akt/mTOR pathway.

Additive Benefits of Radium-223 Dichloride and Bortezomib Combination in a Systemic Multiple Myeloma Mouse Model.

Osteolytic bone disease is a hallmark of multiple myeloma (MM) mediated by MM cell proliferation, increased osteoclast activity, and suppressed osteoblast function. The proteasome inhibitor bortezomib targets MM cells and improves bone health in MM patients. Radium-223 dichloride (radium-223), the first targeted alpha therapy approved, specifically targets bone metastases, where it disrupts the activity of both tumor cells and tumor-supporting bone cells in mouse models of breast and prostate cancer bone metastasis. We hypothesized that radium-223 and bortezomib combination treatment would have additive effects on MM. In vitro experiments revealed that the combination treatment inhibited MM cell proliferation and demonstrated additive efficacy. In the systemic, syngeneic 5TGM1 mouse MM model, both bortezomib and radium-223 decreased the osteolytic lesion area, and their combination was more effective than either monotherapy alone. Bortezomib decreased the number of osteoclasts at the tumor–bone interface, and the combination therapy resulted in almost complete eradication of osteoclasts. Furthermore, the combination therapy improved the incorporation of radium-223 into MM-bearing bone. Importantly, the combination therapy decreased tumor burden and restored body weights in MM mice. These results suggest that the combination of radium-223 with bortezomib could constitute a novel, effective therapy for MM and, in particular, myeloma bone disease.

High in vitro and in vivo synergistic activity between mTORC1 and PLK1 inhibition in adenocarcinoma NSCLC.

Significant rational is available for specific targeting of PI3K/AKT/mTOR pathway in the treatment of non-small cell lung cancer (NSCLC). However, almost all clinical trials that have evaluated Pi3K pathway-based monotherapies/combinations did not observe an improvement of patient’s outcome. The aim of our study was therefore to define combination of treatment based on the determination of predictive markers of resistance to the mTORC1 inhibitor RAD001/Everolimus. An in vivo study showed high efficacy of RAD001 in NSCLC Patient-Derived Xenografts (PDXs). When looking at biomarkers of resistance by RT-PCR study, three genes were found to be highly expressed in resistant tumors, i.e., PLK1, CXCR4, and AXL. We have then focused our study on the combination of RAD001 + Volasertib, a PLK1 inhibitor, and observed a high antitumor activity of the combination in comparison to each monotherapy; similarly, a clear synergistic effect between the two compounds was found in an in vitro study. Pharmacodynamics study demonstrated that this synergy was due to (1) tumor vascularization decrease, increase of the HIF1 protein expression and decrease of the intracellular pH, and (2) decrease of the Carbonic Anhydrase 9 (CAIX) protein that could not correct intracellular acidosis. In conclusion, all these preclinical data strongly suggest that the inhibition of mTORC1 and PLK1 proteins may be a promising therapeutic approach for NSCLC patients.

Radium-223 Treatment Increases Immune Checkpoint Expression in Extracellular Vesicles from the Metastatic Prostate Cancer Bone Microenvironment.

Radium-223 prolongs survival in a fraction of men with bone metastatic prostate cancer (PCa). However, there are no markers for monitoring response and resistance to Radium-223 treatment. Exosomes are mediators of intercellular communication and may reflect response of the bone microenvironment to Radium-223 treatment. We performed molecular profiling of exosomes and compared the molecular profile in patients with favorable and unfavorable overall survival. We performed exosomal transcriptome analysis in plasma derived from our preclinical models (MDA-PCa 118b tumors, TRAMP-C2/BMP4 PCa) and from the plasma of 25 patients (paired baseline and end of treatment) treated with Radium-223. All samples were run in duplicate, and array data analyzed with fold changes +2 to -2 and P < 0.05. We utilized the preclinical models to establish that genes derived from the tumor and the tumor-associated bone microenvironment (bTME) are differentially enriched in plasma exosomes upon Radium-223 treatment. The mouse transcriptome analysis revealed changes in bone-related and DNA damage repair-related pathways. Similar findings were observed in plasma-derived exosomes from patients treated with Radium-223 detected changes. In addition, exosomal transcripts detected immune-suppressors (e.g., PD-L1) that were associated with shorter survival to Radium-223. Treatment of the Myc-CaP mouse model with a combination of Radium-223 and immune checkpoint therapy (ICT) resulted in greater efficacy than monotherapy. These clinical and coclinical analyses showed that RNA profiling of plasma exosomes may be used for monitoring the bTME in response to treatment and that ICT may be used to increase the efficacy of Radium-223.

A phase I/II study of combination olaparib and radium-223 in men with metastatic castration-resistant prostate cancer with bone metastases (COMRADE): A trial in progress.

TPS182 Background: Radium-223 is an α-emitting radioisotope that induces DNA double-stranded breaks leading to cell death and has demonstrated improvement in overall survival in men with metastatic castration-resistant prostate cancer (mCRPC) with bone metastases. PARP inhibitors, including olaparib and rucaparib, inhibit repair of DNA single-stranded beaks and have demonstrated clinical efficacy in mCRPC patients harboring alterations in the homologous recombination repair (HRR) pathway. In extensive preclinical cancer models, PARP inhibitors have shown efficacy as radiosensitizing agents. We designed a phase 1/2 trial to test the clinical hypothesis that the combination of radium-223 with olaparib will demonstrate anti-tumor activity in patients with mCRPC irrespective of underlying HRR deficiency status. Methods: This is an open label, multi-center, phase 1/2 study (NCT03317392) evaluating the dosing, safety and efficacy of olaparib in combination with radium-223 in men with mCRPC with bone metastases. Patient must have 2 or more bone metastases and at least 1 bone metastasis that has not been treated with prior radiation therapy. Key exclusion criteria include the presence of visceral metastases or malignant lymphadenopathy exceeding 4 cm and prior therapy with radium-223 and/or PARP inhibitors. The phase 1 component of the study uses a 3+3 dose escalation design to determine the recommended phase 2 dose of olaparib in combination with standard of care dosing of Radium-223. The primary endpoint of the phase 1 component is safety. The phase 2 component of the study is an open-label, randomized study evaluating the combination of olaparib and radium-223 compared to radium-223 alone. The primary endpoint of the phase 2 component is radiographic progression-free survival as defined by Prostate Cancer Working Group 3 guidelines for bone metastases and RECIST v1.1 for non-bone metastases. Secondary endpoints include time to PSA progression, PSA response, time to subsequent therapy, time to first skeletal event, overall survival, and safety. Exploratory endpoints include stratification of response based on HRR alterations, whole exome sequencing of plasma cell free DNA both at baseline, on treatment, and at progression, and evaluation of changes in the tumor immune microenvironment with therapy. As of October 1, 2020, the phase 1 component has completed accrual and we anticipate opening the phase 2 component by December 2020. Clinical trial information: NCT03317392.

Radium-223 in combination with enzalutamide in metastatic castration-resistant prostate cancer: a multi-centre, phase II open-label study

Background:Radium-223 and enzalutamide are approved agents for patients with metastatic castration-resistant prostate cancer (mCRPC). Combining radium-223 and enzalutamide to improve outcomes is of clinical interest due to their differing modes of action and non-overlapping toxicity profiles.Methods:This phase II study enrolled patients with mCRPC and bone metastases. Patients received six cycles of radium-223 in combination with enzalutamide, followed by enzalutamide alone. The primary endpoint was safety for the combination; secondary endpoints included radiographic/clinical progression-free survival (PFS), PSA PFS, overall survival (OS), change in alkaline phosphatase, patient-reported pain outcomes and skeletal related events.Results:Forty-five patients received the combination treatment: 42 patients (93.3%) received all six cycles. Fourteen patients (31.1%) developed grade 3 or 4 toxicities, most commonly fatigue and neutropaenia. Fractures during the combination period occurred in four patients (8.9%). A further 13 patients (28.9%) developed fractures after completing combination treatment, giving a total of 17 patients (37.8%) who developed a fracture at any time on study. The median time to fracture was greater than 17.2 months [95% confidence interval (CI), 17.2–not estimable]. The median time to PSA progression was 18.1 months (95% CI, 12.68–22.60) and the median time to radiological/clinical progression was 28.0 months (95% CI, 22.54–not reached). At the primary analysis, 19 (42.2%) out of 45 patients had died with a median OS not reached (mean 34.8 months, standard error 1.4).Conclusion:In men with progressive mCRPC and bone metastases, the combination of radium-223 and enzalutamide was tolerable with the majority of patients completing the combination treatment. Bone fractures during the combination period were uncommon; however, we did identify a higher incidence of fractures occurring in patients after completing combination treatment. Bone health agents should be administered and bone health should be closely monitored following treatment with radium-223 and enzalutamide.

Synthesis and validation of [18F]mBPET-1, a fluorine-18 labelled mTOR inhibitor derivative based on a benzofuran backbone

BackgroundTargeted therapy of HER2 positive breast cancer has led to clinical success in some cases with primary and secondary resistance being major obstacles. Due to the substantial involvement of mTOR kinase in cell growth and proliferation pathways it is now targeted in combination treatments to counteract HER2 targeted therapy resistance. However, the selection of receptive patient populations for a specific drug combination is crucial. This work aims to develop a molecular probe capable of identifying patients with tumour populations which are receptive to RAD001 combination therapy. Based on the structure of a mTOR inhibitor specific for mTORC1, we designed, synthesised and characterised a novel benzofuran based molecular probe which suits late stage fluorination via Click chemistry.ResultsSynthesis of the alkyne precursor 5 proceeded in 27.5% yield over 7 linear steps. Click derivatisation gave the non-radioactive standard in 25% yield. Radiosynthesis of [18F]1-((1-(2-Fluoroethyl)-1H-1,2,3-triazol-4-yl) methyl)-4-((5-methoxy-2-phenylbenzofuran-4-yl) methyl) piperazine ([18F]mBPET-1) proceeded over two steps which were automated on an iPhase FlexLab synthesis module. In the first step, 2-[18F]fluoroethylazide ([18F]6) was produced, purified by automated distillation in 60% non-decay-corrected yield and subjected to Click conditions with 5. Semi-preparative RP-HPLC purification and reformulation gave [18F]mBPET-1 in 40% ± 5% (n = 6) overall RCY with a process time of 90 min. Radiochemical purity was ≥99% at end of synthesis (EOS) and ≥ 98% after 4 h at room temperature. Molar activities ranged from typically 24.8 GBq/μmol (EOS) to a maximum of 78.6 GBq/μmol (EOS). Lipophilicity of [18F]mBPET-1 was determined at pH 7.4 (logD7.4 = 0.89). [18F]mBPET-1 showed high metabolic stability when incubated with mouse S9 liver fractions which resulted in a 0.8% drop in radiochemical purity after 3 h. Cell uptake assays showed 1.3–1.9-fold increased uptake of the [18F]mBPET-1 in RAD001 sensitive compared to insensitive cells across a panel of 4 breast cancer cell lines.ConclusionMolecular targeting of mTOR with [18F]mBPET-1 distinguishes mTOR inhibitor sensitive and insensitive cell lines. Future studies will explore the ability of [18F]mBPET-1 to predict response to mTOR inhibitor treatment in in vivo models.

A randomized, double-blind, comparison of radium-223 and placebo, in combination with abiraterone acetate and prednisolone, in castration-resistant metastatic prostate cancer: subgroup analysis of Japanese patients in the ERA 223 study.

ERA 223 compared concurrent abiraterone acetate/prednisolone (AAP) plus radium-223 with AAP plus placebo in men with chemotherapy-naïve asymptomatic or mildly symptomatic metastatic castration-resistant prostate cancer (mCRPC) and bone metastases. We report data from a subgroup of Japanese patients in ERA 223. Patients were randomized to radium-223 (55kBq/kg) or placebo once every 4weeks (max. 6 cycles), and also received oral abiraterone acetate 1000mg once daily plus prednisone/prednisolone 5mg twice daily during and after radium-223/placebo treatment, until a symptomatic skeletal event (SSE). The primary endpoint was SSE-free survival (SSE-FS); overall survival (OS) was a secondary endpoint. Of 806 patients randomized in ERA 223, 114 patients (57 per arm) were enrolled in Japan. SSE-FS was not improved significantly in the radium-223 arm [25.5months, 95% CI 20.6-not estimated (NE)] compared with the placebo arm (28.7months, 95% CI 19.7-NE) (HR = 0.907, 95% CI 0.501-1.642). OS and other secondary endpoints were not improved significantly in the radium-223 arm. The incidence of fracture was 23% and 11% in the radium-223 and placebo arms, respectively. The incidence of death was 32% and 36%, respectively. In the Japanese ERA 223 subgroup, concurrent treatment with AAP and radium-223 did not significantly improve SSE-FS and increased the incidence of fracture, similar to outcomes achieved in the overall population, while an increased incidence of death was not evident. The combination of radium-223 with AAP is not recommended in Japanese patients with asymptomatic or mildly symptomatic mCRPC and bone metastases. Clinical trial registration no: NCT02043678.

An updated analysis evaluating skeletal related events (SREs) in CTRIAL-IE 13-21: Phase II trial of radium-223 (R223) in combination with enzalutamide (ENZA) for patients (pts) with metastatic castration-resistant prostate cancer (mCRPC).

215 Background: This phase II single arm study, previously reported on the safety and tolerability of the combination of R223 and ENZA in pts with mCRPC. R223 in combination with ENZA was well tolerated with acceptable safety and toxicity profiles. Methods: This study enrolled pts with mCRPC to bone with or without visceral/lymph node involvement progressing on ADT. Pts received 6 cycles of R223 (55 kBq/kg IV Q4W) in combination with ENZA (160mg/day), followed by ENZA alone. Bone health agents were initiated as per treating clinician choice. SREs were defined as: a pathologic fracture, spinal cord compression (SCC), necessity for external beam radiation (EBRT) or surgery to bone. SREs during the combination period and after completion of R223 are reported here. An unplanned retrospective analysis of all scans performed on each patient for any fracture was performed and is included. Results: From July 2015 to July 2017, 45 pts were enrolled. 42 pts (93.3%) received all 6 cycles of combination therapy. 16 pts (35.5%) remain on ENZA alone. In total, 6 pts (13.3%) had SREs. 4 developed pathological fractures (femur = 1, vertebrae = 3) while 3 had EBRT for pain. Of these 6 pts, 2 developed SCC requiring EBRT. The average time from starting R223 to SRE was 615 days. 2/6 pts were not receiving bone protection. One pt who developed a pathological fracture has subsequently died related to progressive disease (time to death = 292 days). In the retrospective analysis, 4 pts (8.8%) developed fractures which were associated with a history of trauma (radius = 1, tibia = 1 ribs = 2). 11 pts (24.4%) developed asymptomatic insufficiency fractures (ankle = 1, femur = 1, sacrum = 2, vertebrae = 4, ribs = 4). The average time to insufficiency fracture was 354 days. No interventions were required. The majority of pts (75.5%) on the study were receiving bone health agents. Conclusions: SREs were in keeping with previously published data. In an unplanned retrospective analysis, there was a higher incidence of asymptomatic insufficiency fractures in this cohort of patients, however no interventions were required. Clinical trial information: NCT02225704.

The combination of everolimus and terameprocol exerts synergistic antiproliferative effects in endometrial cancer: molecular role of insulin-like growth factor binding protein 2.

Oncogenic PIK3CA mutations are common in endometrial cancers, and the PI3K/AKT/mTOR pathway is targetable by drugs. We sought to investigate whether the combination of an mTOR inhibitor, everolimus (RAD001), and an AKT inhibitor, terameprocol (M4N), exerts better antiproliferative effects in endometrial cancer. The molecular mechanisms underlying their pharmacological action were also examined. The combination of RAD001 and M4N exerted in vitro synergistic effects on cell viability, apoptosis, and expression of IGFBP2 in endometrial cancer cells. Mechanistically, the Sp1 site on the IGFBP2 promoter was required for RAD001- and M4N-induced downregulation. IGFBP2 protein expression was higher in endometrial cancer than in the normal endometrium (P < 0.001). Furthermore, elevated IGFBP2 histoscores were significantly associated with a lower overall survival (P = 0.021). In conclusion, our in vitro results demonstrate that RAD001 and M4N exert synergistic antiproliferative effects against endometrial cancer cells, which appeared to be mediated by the inhibition of IGFBP2, a key anti-apoptotic regulator. Further clinical studies of this drug combination in patients with endometrial cancer may be warranted, especially in the presence of PIK3CA and IGFBP2 aberrations. KEY MESSAGES: RAD001 and M4N synergistically suppress endometrial cancer growth. IGFBP2 is overexpressed in endometrial cancer. The combination of RAD001 and M4N significantly reduces IGFBP2 overexpression. Sp1 binding site on the IGFBP2 promoter is required for RAD001- and M4N-induced downregulation. High IGFBP2 histoscore in endometrial cancer portends a poor prognosis.

Targeting tumour re-wiring by triple blockade of mTORC1, epidermal growth factor, and oestrogen receptor signalling pathways in endocrine-resistant breast cancer

BackgroundEndocrine therapies are the mainstay of treatment for oestrogen receptor (ER)-positive (ER+) breast cancer (BC). However, resistance remains problematic largely due to enhanced cross-talk between ER and growth factor pathways, circumventing the need for steroid hormones. Previously, we reported the anti-proliferative effect of everolimus (RAD001-mTORC1 inhibitor) with endocrine therapy in resistance models; however, potential routes of escape from treatment via ERBB2/3 signalling were observed. We hypothesised that combined targeting of three cellular nodes (ER, ERBB, and mTORC1) may provide enhanced long-term clinical utility.MethodsA panel of ER+ BC cell lines adapted to long-term oestrogen deprivation (LTED) and expressing ESR1wt or ESR1Y537S, modelling acquired resistance to an aromatase-inhibitor (AI), were treated in vitro with a combination of RAD001 and neratinib (pan-ERBB inhibitor) in the presence or absence of oestradiol (E2), tamoxifen (4-OHT), or fulvestrant (ICI182780). End points included proliferation, cell signalling, cell cycle, and effect on ER-mediated transactivation. An in-vivo model of AI resistance was treated with monotherapies and combinations to assess the efficacy in delaying tumour progression. RNA-seq analysis was performed to identify changes in global gene expression as a result of the indicated therapies.ResultsHere, we show RAD001 and neratinib (pan-ERBB inhibitor) caused a concentration-dependent decrease in proliferation, irrespective of the ESR1 mutation status. The combination of either agent with endocrine therapy further reduced proliferation but the maximum effect was observed with a triple combination of RAD001, neratinib, and endocrine therapy. In the absence of oestrogen, RAD001 caused a reduction in ER-mediated transcription in the majority of the cell lines, which associated with a decrease in recruitment of ER to an oestrogen-response element on the TFF1 promoter. Contrastingly, neratinib increased both ER-mediated transactivation and ER recruitment, an effect reduced by the addition of RAD001. In-vivo analysis of an LTED model showed the triple combination of RAD001, neratinib, and fulvestrant was most effective at reducing tumour volume. Gene set enrichment analysis revealed that the addition of neratinib negated the epidermal growth factor (EGF)/EGF receptor feedback loops associated with RAD001.ConclusionsOur data support the combination of therapies targeting ERBB2/3 and mTORC1 signalling, together with fulvestrant, in patients who relapse on endocrine therapy and retain a functional ER.

Phase II safety and tolerability study of Radium-223 (R223) in combination with enzalutamide (ENZA) in patients (pts) with metastatic castration-resistant prostate cancer (mCRPC): CTRIAL-IE (ICORG) 13-21.

5050Background: R223 and ENZA are standard of care agents in the treatment of patients (pts) with mCRPC. The combination of R223 and ENZA is of interest due to differing modes of action and non-ove...

Radium-223 in the therapeutic sequence of metastatic castration-resistant prostate cancer

ContextRadium-223 is an α-particle transmitter with specific action on bone metastases. The Alpharadin in Symptomatic Prostate Cancer Patients (ALSYMPCA) study showed that radium-223 extended overall survival and delayed the onset of bone events in patients with symptomatic castration-resistant prostate cancer with bone metastases (mCRPC) and without visceral metastases, with a good safety profile. ObjectiveTo review the new scientific evidence on radium-223 based on prespecified and post hoc analyses of the ALSYMPCA study and on early-access programs after the publication of the ALSYMPCA study, thereby providing new data on the management of patients with mCRPC. Acquisition of evidenceWe searched for evidence on PubMed and in the abstracts of international urology and oncology congresses, as well as ongoing clinical trials (ClinicalTrials.gov). Synthesis of the evidenceThe results of the reviewed studies offer promising results that will broaden the therapeutic benefits of radium-223 to patients with mild symptoms and those with no symptoms. The results also provide preliminary evidence on the benefit of radium-223 treatment after the failure of docetaxel, enzalutamide or abiraterone or the combination of radium-223 with these agents or other therapeutic agents such as bone-targeted agents and immunotherapy. ConclusionRadium-223 can be a treatment option for patients with mild symptoms and can provide a therapeutic benefit after failure of currently available treatments or in combination with these treatments. This evidence should be corroborated in clinical trials before being added to clinical practice.

Radio-223 en la secuencia terapéutica del cáncer de próstata resistente a la castración metastásico

ContextRadium-223 is an □ -particle transmitter with specific action on bone metastases. The Alpharadin in Symptomatic Prostate Cancer Patients (ALSYMPCA) study showed that radium-223 extended overall survival and delayed the onset of bone events in patients with symptomatic castration-resistant prostate cancer with bone metastases (mCRPC) and without visceral metastases, with a good safety profile. ObjectiveTo review the new scientific evidence on radium-223 based on prespecified and post-hoc analyses of the ALSYMPCA study and on early-access programs after the publication of the ALSYMPCA study, thereby providing new data on the management of patients with mCRPC. Acquisition of evidenceWe searched for evidence on PubMed and in the abstracts of international urology and oncology congresses, as well as ongoing clinical trials (ClinicalTrials.gov). Synthesis of the evidenceThe results of the reviewed studies offer promising results that will broaden the therapeutic benefits of radium-223 to patients with mild symptoms and those with no symptoms. The results also provide preliminary evidence on the benefit of radium-223 treatment after the failure of docetaxel, enzalutamide or abiraterone or the combination of radium-223 with these agents or other therapeutic agents such as bone-targeted agents and immunotherapy. ConclusionRadium-223 can be a treatment option for patients with mild symptoms and can provide a therapeutic benefit after failure of currently available treatments or in combination with these treatments. This evidence should be corroborated in clinical trials before being added to clinical practice.