Toxic effects of sirolimus and everolimus on the development and behavior of zebrafish embryos.

Sirolimus and everolimus have been widely used in children. These mammalian target of rapamycin (mTOR) inhibitors have shown excellent efficacy not only in organ transplant patients as immunosuppressive agents but also in patients with some other diseases. However, whether mTOR inhibitors can affect the growth and development of children is of great concern. In this study, using zebrafish models, we discovered that sirolimus and everolimus could slow the development of zebrafish, affecting indicators such as survival, hatching, deformities, body length, and movement. In addition to these basic indicators, sirolimus and everolimus had certain slowing effects on the growth and development of the nervous system, blood vessels, and the immune system. These effects were dose dependent. When the drug concentration reached or exceeded 0.5 µM, the impacts of sirolimus and everolimus were very significant. More interestingly, the impact was transient. Over time, the various manifestations of experimental embryos gradually approached those of control embryos. We also compared the effects of sirolimus and everolimus on zebrafish, and we revealed that there was no significant difference between these drugs in terms of their effects. In summary, the dose of sirolimus and everolimus in children should be strictly controlled, and the drug concentration should be monitored over time. Otherwise, drug overdosing may have a certain impact on the growth and development of children.

Dosing-time dependent testicular toxicity of everolimus in mice.

The circadian timing system controls many biological functions in mammals including drug metabolism and detoxification, cell cycle events, and thus may affect pharmacokinetics, target organ toxicity and efficacy of medicines. Selective mTOR (mammalian target of rapamycin) inhibitor everolimus is an immunosuppressant and anticancer drug that is effective against several cancers. The aim of this study was to investigate dosing-time dependent testicular toxicity of subacute everolimus administration in mice. C57BL/6 J male mice were synchronized with Light-Dark (12h:12 h) cycle, with Light-onset at Zeitgeber Time (ZT)-0. Everolimus (5 mg/kg/day) was administered orally to mice at ZT1rest-span or ZT13activity-span for 4 weeks. Body weight loss, clinical signs, changes in testicular weights, testis histology, spermatogenesis and proliferative activity of germinal epithelium of seminiferous tubules were examined. Steady-state everolimus concentrations in testes were determined with validated HPLC method. Everolimus toxicity was less severe following dosing at ZT13 compared to ZT1, as shown with least body weight loss (p<0.001), least reductions in testes weights (p<0.001) and least histopathological findings. Everolimus-induced histological changes on testes included vacuolisation and atrophy of germinal epithelium, and loss of germinal cell attachment. The severity of everolimus-induced histological toxicity on testes was significantly more evident in mice treated at ZT1 than ZT13 (p<0.001). Spermatogenic cell population significantly decreased when everolimus administered at ZT1 compared to ZT13 (p<0.001). Proliferative activity of germinal epithelium was significantly decreased due to treatment at ZT1 compared to ZT13 (p<0.001). Everolimus concentrations in testes indicated a pronounced circadian variation, which was greater in mice treated at ZT1 compared to ZT13 (p<0.05). Our study revealed dosing-time dependent testicular toxicity of everolimus in mice, which was greater in severity when everolimus administered at early rest-span (daytime-ZT1) than early activity-span (nighttime-ZT13). These findings support the concept of everolimus chronotherapy for minimizing reproductive toxicity and increasing the tolerability of everolimus, as a clinical advantage.

Relationship between metabolic toxicity and efficacy of everolimus in patients with neuroendocrine tumors: A pooled analysis from the randomized, phase 3 RADIANT-3 and RADIANT-4 trials.

BACKGROUND: Hyperglycemia and hypercholesterolemia are class effects of mammalian target of rapamycin inhibitors such as everolimus. This post hoc pooled analysis assessed the potential impact of these events on the efficacy of everolimus. METHODS: Patients with advanced, low- or intermediate-grade pancreatic, gastrointestinal, or lung neuroendocrine tumors received either oral everolimus at 10 mg/d or a placebo in the RAD001 in Advanced Neuroendocrine Tumors 3 (RADIANT-3) and RAD001 in Advanced Neuroendocrine Tumors 4 (RADIANT-4) trials. A landmark progression-free survival (PFS) analysis by central review was performed for patients treated for at least 16 weeks (n = 308) and according to the occurrence of any-grade adverse events (AEs) within this treatment period. RESULTS: The overall PFS with everolimus from the pooled analysis was 11.4 months (95% confidence interval, 11.01-13.93 months), which was consistent with the findings of RADIANT-3 and RADIANT-4. Overall, 19.1% and 9.8% of patients in RADIANT-3 and 11.9% and 6.4% of patients in RADIANT-4 developed any-grade hyperglycemia and hypercholesterolemia, respectively (regardless of the study drug). The duration of everolimus exposure was longer in patients who developed these AEs versus patients without these AEs. Overall, 308 patients were exposed to treatment for at least 16 weeks (hyperglycemia, 39 of 269 patients; hypercholesterolemia, 20 of 288 patients). No association was observed between the development of these AEs and PFS (18.8 and 14.1 months with and without hyperglycemia, respectively, and 14.1 and 14.8 months with and without hypercholesterolemia, respectively). CONCLUSIONS: Although limitations apply because of the small number of AEs observed, there was no significant impact of these AEs on PFS; this suggests similar efficacy in the presence or absence of these events.

Everolimus after failure of one prior VEGF-targeted therapy in metastatic renal cell carcinoma: Final results of the MARC-2 trial.

MARC-2, a prospective, multicenter phase IV trial, aimed to investigate clinical outcomes in patients with metastatic renal cell carcinoma (mRCC) treated with everolimus after failure of one initial vascular endothelial growth factor receptor tyrosine kinase inhibitor (VEGFR-TKI) therapy and to identify subgroups benefiting most, based on clinical characteristics and biomarkers. Patients with clear cell mRCC failing one initial VEGFR-TKI received everolimus until progression or unacceptable toxicity. Primary endpoint was 6-month progression-free survival rate (6moPFS). Secondary endpoints were overall response rate (ORR), PFS, overall survival (OS), and safety. Between 2011 and 2015, 63 patients were enrolled. Median age was 65.4 years (range 43.3-81.1). 6moPFS was 39.3% (95% confidence interval [CI], 27.0-51.3) overall, 54.4% (95% CI, 35.2-70.1) vs 23.7% (95% CI, 10.5-39.9) for patients aged ≥65 vs <65 years and 51.4% (95% CI, 34.7-65.7) vs 18.2% (95% CI, 5.7-36.3) for patients with body mass index (BMI) >25 vs ≤25 kg/m2 . A Cox proportional hazards model confirmed a longer PFS for patients aged ≥65 years (hazard ratio [HR] 0.46; 95% CI, 0.26-0.80) and a longer OS for patients with BMI >25 kg/m2 (HR 0.36; 95% CI, 0.18-0.71). Median PFS and median OS were 3.8 months (95% CI, 3.2-6.2) and 16.8 months (95% CI, 14.3-24.3). ORR was 7.9% and disease control rate was 60.3%. No new safety signals emerged. Most common adverse events were stomatitis (31.7%), fatigue (31.7%), and anemia (30.2%). One patient died from treatment-related upper gastrointestinal hemorrhage. Everolimus remains a safe and effective treatment option for mRCC patients after one prior VEGFR-TKI therapy. Patients aged ≥65 years and patients with BMI >25 kg/m2 benefited most.

Preclinical Evaluation of a Novel Sirolimus-Eluting Iron Bioresorbable Coronary Scaffold in Porcine Coronary Artery at 6 Months.

OBJECTIVES: The aim of this study was to investigate the operability, 6-month efficacy, and safety of the novel sirolimus-eluting iron bioresorbable coronary scaffold (IBS) system compared with a cobalt-chromium everolimus-eluting stent (EES) (XIENCE Prime stent) in porcine coronary arteries. BACKGROUND: Bioresorbable scaffolds have been considered the fourth revolution in percutaneous coronary intervention. However, the first-generation bioresorbable scaffold showed suboptimal results. METHODS: Forty-eight IBS and 48 EES were randomly implanted into nonatherosclerotic swine. The operability, efficacy, and safety of the IBS and EES were evaluated using coronary angiography, optical coherence tomography, micro-computed tomography, scanning electron microscopy, and histopathologic evaluation at 7, 14, 28, 90, and 180 days after implantation. RESULTS: The operability of the ultrathin IBS (∼70 µm) was comparable with that of the EES, except for its visibility. There was no statistically significant difference in area stenosis between the IBS and EES from 28 to 180 days. The IBS maintained its integrity up to 90 days without corrosion, while corrosion was observed in a few struts in 2 of 10 IBS at 180 days. The percentage of endothelialization of IBS was higher than that of XIENCE Prime stents within 14 days after implantation. The fibrin score was higher in the IBS group at 28 days but comparable with the EES group at 90 and 180 days. No scaffold or stent thrombosis was seen in either group. No abnormal histopathologic changes in scaffolded or stented vessel segments and 5 main remote organs were observed in either group. CONCLUSIONS: Preclinical results suggest that the novel IBS has comparable operability, mid-term efficacy, and safety with the EES, and its corrosion profile in porcine coronary arteries is reasonable, which could support initial clinical study of the IBS.

The immune system as a chronotoxicity target of the anticancer mTOR inhibitor everolimus.

The circadian timing system controls many biological functions in mammals including xenobiotic metabolism, detoxification, cell proliferation, apoptosis and immune functions. Everolimus is a mammalian target of rapamycin inhibitor, whose immunosuppressant properties are both desired in transplant patients and unwanted in cancer patients, where it is indicated for its antiproliferative efficacy. Here we sought whether everolimus circadian timing would predictably modify its immunosuppressive effects so as to optimize this drug through timing. C57BL/6J mice were synchronized with light-dark 12h:12h, with L onset at Zeitgeber Time (ZT) 0. Everolimus was administered orally to male (5 mg/kg/day) and female mice (15 mg/kg/day) at ZT1, during early rest span or at ZT13, during early activity span for 4 weeks. Body weight loss, as well as hematological, immunological and biochemical toxicities, were determined. Spleen and thymus were examined histologically. Everolimus toxicity was less severe following dosing at ZT13, as compared to ZT1, as shown with least body weight inhibition in both genders; least reductions in thymus weight both in males (p < 0.01) and females (p < 0.001), least reduction in female spleen weight (p < 0.05), and less severe thymic medullar atrophy both in males (p < 0.001) and females (p < 0.001). The mean circulating counts in total leukocytes, total lymphocytes, T-helper and B lymphocytes displayed minor and non-significant changes following dosing at ZT13, while they were decreased by 56.9% (p < 0.01), 45.5% (p < 0.01), 43.1% (p < 0.05) and 48.7% (p < 0.01) after everolimus at ZT1, respectively, in only male mice. Chronotherapy of everolimus is an effective way to increase the general tolerability and decrease toxicity on the immune system.

mTOR inhibition reduces growth and adhesion of hepatocellular carcinoma cells in vitro.

Mechanistic target of rapamycin (mTOR) signaling is typically increased in hepatocellular carcinoma (HCC). A panel of HCC cell lines (HepG2, Hep3B and HuH6) was exposed to various concentrations of the mTOR inhibitors, everolimus and temsirolimus, in order to investigate their effects on cell growth, clonal formation, cell cycle progression, and adhesion and chemotactic migration using MTT and clonal cell growth assays, fluorometric detection of cell cycle phases and a Boyden chamber assay. In addition, integrin α and ß adhesion receptors were analyzed by flow cytometry and blocking studies using function blocking monoclonal antibodies were conducted to explore functional relevance. The results demonstrated that everolimus and temsirolimus significantly suppressed HCC cell growth and clonal formation, at 0.1 or 1 nM (depending on the cell line). In addition, the number of cells in G0/G1 phase was increased in response to drug treatment, whereas the number of G2/M phase cells was decreased. Drug treatment also considerably suppressed HCC cell adhesion to immobilized collagen. Integrin profiling revealed strong expression of integrin α1, α2, α6 and ß1 subtypes; and integrin α1 was upregulated in response to mTOR inhibition. Suppression of integrin α1 did not affect cell growth; however, it did significantly decrease adhesion and chemotaxis, with the influence on adhesion being greater than that on motility. Due to a positive association between integrin α1 expression and the extent of adhesion, whereby reduced receptor expression was correlated to decreased cell adhesion, it may be hypothesized that the adhesion­blocking effects of mTOR inhibitors are not associated with mechanical contact inhibition of the α1 receptor but with integrin α1­dependent suppression of oncogenic signaling, thus preventing tumor cell­matrix interaction.

Continuous low plasma concentrations of everolimus provides equivalent efficacy to oral daily dosing in mouse xenograft models of human cancer.

PURPOSE: Everolimus is a drug used successfully in a number of different oncology indications, but significant on-target toxicities exist. We explored the possibility of improving the therapeutic index (TI) by studying alternative means of administering the drug based upon low continuous dosing. METHODS: All studies were performed using naïve nude mice or nude mice bearing s.c. human renal 786-O tumours or human breast MDA-MB-468 tumours. Everolimus was administered via a standard emulsion, either i.v., p.o., i.p., s.c., or via s.c. osmotic mini-pumps (MP) or via poly-lactic-co-glycolic (PLGA)-microparticles (PLGA-µP) prepared from everolimus powder injected s.c. Total-drug levels in blood, plasma or tissues were quantified ex vivo by LC-MS/MS. Efficacy studies were performed over 2-3 weeks and toxicity assessed by changes in body weight, glucose and white blood cell count. Effects on tumour activity biomarkers were quantified using reverse-phase protein array. RESULTS: Everolimus administration s.c. in an emulsion decreased the absorption rate but increased the C max and bio-availability of everolimus compared to standard approaches of administration p.o. or i.p. Everolimus administration s.c. via MP or PLGA-µP reduced the C max and provided continuous low concentrations of everolimus in the plasma, which inhibited tumour pS6/S6 to a similar degree to oral administration. Toxicities such as changes in body weight or white blood cell count were unaffected. Provided the everolimus concentration was above the free unbound IC50 for proliferation of the tumour cell line, efficacy could be achieved equivalent to that provided by standard oral administration. However, an overall improvement in the TI could not be demonstrated. CONCLUSIONS: Continuous low plasma concentrations of everolimus can provide strong efficacy in preclinical models, which if translatable to the clinic may reduce on-target toxicities and so increase the TI.

Prediction of Everolimus Toxicity and Prognostic Value of Skeletal Muscle Index in Patients With Metastatic Renal Cell Carcinoma.

BACKGROUND: The objective of the study was to assess the prognostic role of skeletal muscle index (SMI) in metastatic renal cell carcinoma (mRCC) patients treated with everolimus, and its effect of on everolimus-induced toxicity. PATIENTS AND METHODS: Consecutive mRCC patients treated with everolimus between February 2007 and November 2014 underwent computed tomography scans at a single center performed by the same radiologist. SMI was assessed before everolimus treatment using the L3 cross-sectional area. Overall survival (OS) was analyzed according to SMI value. Results were adjusted using the International Metastatic Database Consortium (IMDC) prognostic group, body mass index (BMI), and/or number of previous tyrosine kinase inhibitor lines (NPL). RESULTS: One hundred twenty-four mRCC patients (mean age, 60.21 years) were treated with everolimus as second- or third-line (82.3%) or > third-line (17.7%) therapy. Most patients (87.9%) had clear cell carcinoma. IMDC prognostic group was "favorable" (32.3%), "intermediate" (50%), or "poor" (17.7%). Median SMI was 40.75. OS was longer in patients from the highest versus lowest SMI tercile: 21.9 versus 10 months (P = .002). Continuous SMI at baseline was not significantly associated with OS after adjustment for IMDC prognostic group, BMI, or NPL but the highest versus lowest SMI tercile was an independent prognostic factor in multivariate analysis (P = .025). There was no difference in everolimus toxicity between SMI tercile groups. CONCLUSION: SMI was an independent prognostic factor for mRCC patients treated with everolimus. Whether this provides additional prognostic value to IMDC criteria needs to be confirmed in a larger cohort. SMI does not seem to be predictive of everolimus-induced toxicity.

Risk of gastrointestinal toxicities with PD-1 inhibitors in cancer patients: A meta-analysis of randomized clinical trials.

BACKGROUND: Anti-programmed cell death protein 1 (PD-1) antibodies have demonstrated significant clinical activity in many cancer entities. Gastrointestinal toxicities are one of its major side effects, but the overall risks have not been systematically evaluated. Thus, the purpose of this study was to evaluate the incidence and risk of gastrointestinal toxicities with PD-1 inhibitors in cancer patients through a meta-analysis. METHODS: Eligible studies were searched for in PubMed, Embase, and the Cochrane Library. We included randomized controlled trials with cancer patients treated with PD-1 inhibitors with adequate data on gastrointestinal adverse events. RESULTS: A total of 14 randomized controlled trials involving 7508 patients met eligibility criteria for this meta-analysis. The relative risk of all-grade diarrhea and colitis was 0.66 (95% confidence interval (CI): [0.50, 0.87]; P = .003) and 3.36 (95% CI: [1.25, 9.04]; P = .02), respectively. The relative risk of high-grade diarrhea and colitis was 0.58 (95% CI: [0.30, 1.11]; P = .10) and 4.31 (95% CI: [1.11, 16.79]; P = .04), respectively. Compared with ipilimumab alone, the nivolumab/ipilimumab combination was associated with a higher risk of developing all-grade diarrhea. Additionally, PD-1 inhibitor monotherapy resulted in a lower risk of developing gastrointestinal adverse events compared with ipilimumab alone. CONCLUSIONS: Our meta-analysis has demonstrated that the use of PD-1 inhibitors is associated with an increased risk of colitis compared with chemotherapy or everolimus.

Birth defects in juvenile Wistar rats after exposure to immunosuppressive drugs during pregnancy.

INTRODUCTION: Immunosuppressive drugs and their active metabolites can cross the placental barrier and enter fetal circulation. The adverse effects on the fetus include chromosomal aberrations, structural malformations, organ-specific toxicity and intrauterine growth retardation. The aim of our study was to investigate the impact of "safe" and "contraindicated" immunosuppressive drugs on birth defects in juvenile Wistar rats after exposure of pregnant female rats to these drugs. MATERIAL AND METHODS: The study was conducted on 32 female Wistar rats, subjected to immunosuppressive regimens most commonly used in therapy of human kidney transplant recipients. The animals received drugs by oral gavage 2 weeks before pregnancy and during 3 weeks of pregnancy. RESULTS: Treatment with mycophenolate mofetil and everolimus turned out to be toxic. We have noticed a significantly reduced number of live births in all pregnant rats exposed to these drugs in combination with calcineurin inhibitors and prednisone. Malformations and histological changes of fetal organs were confirmed after mycophenolate mofetil exposure during pregnancy. CONCLUSIONS: Mycophenolate mofetil turned out to be more toxic when used with tacrolimus than with cyclosporin (delivery of live offspring was possible only in the latter group). Everolimus in combination with cyclosporin effectively suppressed the fetal maturation in utero, but did not contribute to the development of malformations.

Everolimus in patients with metastatic renal cell carcinoma previously treated with bevacizumab: a prospective multicenter study CRAD001LRU02T.

Everolimus is an orally administered inhibitor of the mammalian target of rapamycin (mTOR) recommended for patients with metastatic renal cell carcinoma (mRCC) who progressed on previous vascular endothelial growth factor (VEGF) receptor-tyrosine kinase inhibitor therapy. Efficacy of everolimus in patients who progressed on anti-VEGF monoclonal antibody bevacizumab is unknown. We did a multicenter prospective trial of everolimus in patients with mRCC whose disease had progressed on bevacizumab ± interferon alpha (IFN). Patients with clear-cell mRCC which had progressed on bevacizumab ± IFN received everolimus 10 mg once daily. The primary end point was the proportion of patients remaining progression-free for 56 days, and a two-stage Simon design was used, with 80% power and an alpha risk of 5%. This study is registered with ClinicalTrials.gov, number NCT02056587. From December 2011 to October 2013, a total of 37 patients (28 M, 9 F) were enrolled. Median age was 60.5 years (range 41-66), 1% had Eastern Cooperative Oncology Group Performance Status (ECOG PS) >2, and Memorial Sloan-Kettering Cancer Center (MSKCC) favorable/intermediate risk was 38/62%. Five (14%) patients had a confirmed partial response and 26 (70%) patients had a stable disease. Median progression-free survival was 11.5 months (95% CI, 8.8-14.2). Median overall survival was not reached. No grade 3 or 4 treatment-related toxicities were observed. The most common grade 2 adverse events were fatigue (19%) and pneumonitis (8%). Everolimus demonstrated a favorable toxicity profile and promising anti-tumor activity as a second-line therapy in metastatic renal cell carcinoma (RCC) patients previously treated with bevacizumab ± IFN.