Use Of mTOR Inhibitors Research Articles

TNO155 is a selective SHP2 inhibitor to target PTPN11-dependent oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is known to be driven by multiple intricated receptor tyrosine kinases (RTKs) including EGFR, PI3K/AKT and MAPK signaling pathways. However, whilst targeting EGFR with cetuximab has been approved for the treatment of OSCC, other single-agent inhibitors of the RTKs have shown modest effects in improving survival. From the genome-wide CRISPR/Cas9 screen on 21 OSCC cell lines, we have identified PTPN11 among the top essential genes in OSCC. PTPN11 encodes for SHP2, a phosphatase that acts as a master signal transducer, downstream of various RTKs. Although PTPN11 overexpression has been reported in OSCC, little is known about its role as an essential gene for OSCC survival and its potential as a therapeutic target. Herein, we confirmed that PTPN11 is an essential gene in OSCC where its deletion significantly impacted cell survival. We evaluated three SHP2 inhibitors on 21 OSCC cell lines and found TNO155 to be significantly associated with CRISPR dependency score. We showed that TNO155 caused dose-dependent suppression on p-ERK and p-MEK, and suppresses the JAK/STAT pathway via downregulating p-JAK1, p-STAT1, p-STAT3. Furthermore, we confirmed that the combination of the mTOR inhibitor, everolimus with TNO155 is synergistic in OSCC. In summary, PTPN11 is a promising therapeutic target in OSCC that can be selectively targeted by SHP2 inhibitor such as TNO155. Our findings on the use of mTOR inhibitor, everolimus to overcome resistance to TNO155 are essential to inform on next phases of clinical trials which is warranted for the treatment of OSCC.

The Role of mTOR in the Doxorubicin-Induced Cardiotoxicity: A Systematic Review.

Doxorubicin (DOX) is a chemotherapy drug known to induce metabolic changes in the heart, leading to potential heart toxicity. These changes impact various cellular functions and pathways such as disrupting the mechanistic target of rapamycin (mTOR) signaling pathway. The study aimed to investigate the effect of DOX on the mTOR pathway through an in vivo systematic review. Databases were searched on September 11, 2023. We finally included 30 in vivo studies that examined the mTOR expression in cardiac tissue samples. The present study has shown that the PI3K/AKT/mTOR, the AMPK/mTOR, the p53/mTOR signaling, the mTOR/TFEB pathway, the p38 MAPK/mTOR, the sestrins/mTOR, and the KLF15/eNOS/mTORC1 signaling pathways play a crucial role in the development of DOX-induced cardiotoxicity. Inhibition or dysregulation of these pathways can lead to increased oxidative stress, apoptosis, and other adverse effects on the heart. Strategies that target and modulate the mTOR pathways, such as the use of mTOR inhibitors like rapamycin, have the potential to enhance the anticancer effects of DOX while also mitigating its cardiotoxic side effects.

Safety and efficacy of COVID-19 vaccination in the Chinese population with pulmonary lymphangioleiomyomatosis: a single-center retrospective study

BackgroundThe safety and efficacy of vaccination against coronavirus disease 2019 (COVID-19) in patients with lymphangioleiomyomatosis (LAM) is still unclear. This study investigates COVID-19 vaccine hesitancy, vaccine safety and efficacy, and COVID-19 symptoms in LAM patients.ResultsIn total, 181 LAM patients and 143 healthy individuals responded to the questionnaire. The vaccination rate of LAM patients was 77.34%, and 15.7% of vaccinated LAM patients experienced adverse events. Vaccination decreased the risk of LAM patients developing anorexia [OR: 0.17, 95% CI: (0.07, 0.43)], myalgia [OR: 0.34, 95% CI: (0.13, 0.84)], and ageusia [OR: 0.34, 95% CI: (0.14, 0.84)]. In LAM patients, a use of mTOR inhibitors reduced the risk of developing symptoms during COVID-19, including fatigue [OR: 0.18, 95% CI: (0.03, 0.95)], anorexia [OR: 0.30, 95% CI: (0.09, 0.96)], and ageusia [OR: 0.20, 95% CI: (0.06, 0.67)].ConclusionsVaccination rates in the LAM population were lower than those in the general population, as 22.7% (41/181) of LAM patients had hesitations regarding the COVID-19 vaccine. However, the safety of COVID-19 vaccination in the LAM cohort was comparable to the healthy population, and COVID-19 vaccination decreased the incidence of COVID-19 symptoms in LAM patients. In addition, mTOR inhibitors seem not to determine a greater risk of complications in patients with LAM during COVID-19.

Racial differences in genomic profiles and targeted treatment use in ER+ HER2- metastatic breast cancer.

1017 Background: Despite well-documented disparities in survival between patients (pts) with Black and White racial backgrounds, there are limited data on racial equity of targeted treatment use for pts with estrogen receptor positive, HER2 negative (ER+/HER2-) metastatic breast cancer (MBC). We evaluated differences in circulating tumor DNA (ctDNA) genomic alterations in Black and White pts with ER+/HER2- MBC. Methods: This retrospective cohort study analyzed a database of 1327 pts with MBC who were treated at Washington University in St. Louis, Massachusetts General Hospital, and Northwestern University and had ctDNA testing through the commercially available Guardant360 assay. Progesterone receptor (PR) status of the ER+/HER2- pts was identified to categorize pts as ER+/PR+/HER2- (N=60 Black, N=435 White) and ER+/PR-/HER2- (N=24 Black, N=237 White). Pts were evaluated by self-reported race and use of PIK3CA, CDK4/6, and mTOR inhibitors, either through clinical trial enrollment or after FDA approval. A multivariate logistic analysis was performed to determine genomic and prognostic differences by race. Overall survival (OS) from time of first ctDNA testing was determined by subgroup. Results: Black pts with PIK3CA single nucleotide variants (SNVs) were significantly less likely to receive targeted therapy than White pts (5.9%, 1/17 pts vs. 28.8%, 45/156 pts, Fisher’s exact test p=0.045), while there was no difference in use of CDK4/6 or mTOR inhibitors. None of the Black pts with PIK3CA mutations were enrolled in clinical trials vs. 11.5% of White pts. Black pts with ER+/PR+/HER2- tumors were more likely to have CCND1 copy number variation (cnv) (odds ratio (OR) 2.4, 95% confidence interval (CI) 1.1-5.4, p=0.030) when compared with White pts. Black pts with PR- tumors were more likely to have de novo metastatic disease (OR 3.4, 95% CI 1.1-10.8, p=0.034) and GATA3SNV (OR 3.5, 95% CI 1.04-11.6, p=0.044). KRAS cnv was more common in White PR- pts (HR 2.9, CI 1.02-8.3, p=0.045). There were significant differences in OS between Black and White pts with ER+/PR+/HER2- tumors (median OS of 25 vs. 32 months, respectively) and for Black and White pts with ER+/PR-/HER2- MBC, (median OS of 9.1 vs. 21 months, respectively, log-rank test p=0.00093). Conclusions: To our knowledge, this is the largest clinicogenomic dataset comparing genomic alterations and targeted treatment use by race in MBC. We identified significant disparities in the use of PI3K inhibitors for Black pts while other drugs that do not require genomic profiling were similarly utilized. OS and clinical trial enrollment disparities are consistent with prior findings and must continue to be addressed. Further research is needed to validate these findings, elucidate the factors contributing to these disparities, and explore interventions to improve racial disparities in use of precision medicine therapies and enrollment in clinical trials.

#1327 mTOR inhibitors in kidney transplant recipients: long-term efficacy and discontinuation causes

Abstract Background and Aims mTOR inhibitors use in kidney transplantation showed conflicting results, but their use as add-on treatment to calcineurin inhibitors (CNI) is still considered a valuable option. High frequency of drug discontinuation hinders their use in clinical practice. We present a real-life study on long term efficacy of mTOR inhibitors use vs mycophenolic acid (MPA) and the causes of drug discontinuation. Method This is an observational retrospective monocentric study. We analyzed data from 773 patients that underwent kidney transplantation at Hospital Clinic between 2013 and 2019. Induction treatment was based either on basiliximab or a lymphocyte-depleting agent together with methylprednisolone. Maintenance treatment was based either on MPA or mTORi with a CNI. Baseline differences were accounted for with the Inverse Propensity of Treatment Weighting (IPTW). Outcomes explored were death with a functioning graft, graft loss or biopsy-proven rejection. Predictors of outcome were explored through logistic regression or Cox-regression as appropriate. Results 335/773 (43.3%) of the patients received MPA as maintenance treatment, whereas 438/773 (56.6%) received an mTOR inhibitor. Average follow-up was 3.36 years (SD ± 2.04 years). No outcome resulted statistically significant at the logistic regression weighted with IPTW in the subgroup mTORi vs MPA: odds ratio was 1.16 (0.75-1.63, p = 0.57) for death, 0.87 (0.54-1.41, p = 0.59) for graft loss and 1.15 (0.79-1.67, p = 0.45) for biopsy-proven acute rejection. The per-protocol analysis confirmed these results as not statistically significant. Strongest predictors of death resulted having a deceased donor of cardiac death (HR 2.17 (1.06-4.40, p = 0.03), having a delayed graft function (HR 1.9 (1.26-2.87, p = 0.002) and being readmitted within three months from the surgery (HR 1.76 (1.21-2.55, p = 0.003). Diabetic nephropathy as cause of kidney disease was significant as well (HR 2.01 (1.24-3.26, p = 0.004). Proportion of patients with a CMV infection were significantly lower in the mTORi than MPA subgroups (33.5% vs 41.5%, p = 0.02). Proportion of patients developing neoplasias were not significantly different (10% vs 11.3%, p = 0.55). A total of 307/773 (39.7%) of patients changed their immunosuppressive treatment at a median time of 110 days (26.5-375.5). In the MPA subgroup 77/335 (22.9%) changed treatment, whereas in the mTORi subgroup 230/438 (52.5%). The causes of change due to drug-related events were the most represented and related to mTOR treatment: lymphocele in 36/773 (4.6%), complications of the surgical wound in 31/773 (4.1%) and edemas in 23/773 (2.9%) were the most common. Of note, unspecific physician preference was cause of discontinuation in a total of 66/773 (8.5%) patients. Conclusion Our data from a tertiary-center, real-life experience show that mTOR inhibitors are a solid alternative to MPA based protocols, with effectiveness proven at the multivariate and weighted analysis. mTOR treatment has a high rate of discontinuation, with most of the causes represented by post-intervention complications; interestingly, physician preference represent a frequent cause. Further experience and research is needed to optimize mTORi treatment, in order to maintain a therapeutic option for transplanted patients.

#3052 mTOR inhibitors in kidney transplant recipients with high immunological risk: practical insights from clinical experience

Abstract Background and Aims The use of mTOR inhibitors (mTORi) is not usually considered in high immunological risk kidney transplant recipients (KTR) for a perceived increased risk of rejection. However, in most of the studies that examined the combination of mTORi with calcineurin inhibitors (CNI), hypersensitized patients have been excluded from enrollment. The aim of the present study is to analyze our clinical experience with the use of mTORi in association with calcineurin inhibitors (CNI) in this subset of patients. Method Analysis of 212 consecutive kidney transplant recipients with a baseline calculated panel reactive antibody (cPRA) ≥50% who received a graft from June 2013 to December 2019. Immunosuppression was based on tacrolimus, steroids and, alternatively, mycophenolic acid (MPA; n = 96) or mTORi (either sirolimus or everolimus, target trough levels 3-8 ng/ml, n = 116) depending on the active Institution's protocol at the time of transplantation. The outcomes chosen included rejection-free, graft and patient survival and were analyzed by means of Cox-regression analysis. Results Demographic and immunological characteristics were similar between groups, apart from the higher number of living donors in the MPA group (42.7% vs 14.7%%, P < 0.001). Baseline cPRA was 92.5 [76-98]% for the MPA and 94 [77.25-98]% for the mTORi group, respectively (P = 0.882). Induction therapy with lymphocyte-depleting agents was employed in the majority of patients (91.7% in the MPA group and 88.8% in the mTORi group, P = 0.898). Median follow-up time was 2.6 [1.45-4.05] years. Biopsy-proven rejection (either cellular or humoral) occurred in 33.3% of the MPA and in 19.8% of the mTORi group, respectively. Cox-regression analysis of rejection-free survival revealed better rejection-free survival with mTORi versus MPA (HR [95% CI], 0.54 [0.32-0.98], P = 0.028). The only other baseline factor associated with rejection was previous transplantation (HR [95% CI] 1.96 [1.07-3.60], P = 0.030). When entered into a bivariable Cox-regression analysis, both mTORi and previous transplantation maintained a statistical significant association with rejection (mTORi versus MPA HR [95% CI] 0.53 [0.31-0.91], P = 0.023, and previous transplantation HR [95% CI] 2.01 [1.09-3.69], P = 0.024). No differences between mTORi and MPA were noted for graft (HR [95% CI] 0.90 [0.40-2.02], P = 0.807) and patient survival (HR [95% CI] 1.23 [0.60-2.50, P = 0.606). Median creatinine 1 year after transplantation was 1.45 [1.11-1.98]mg/dl for the MPA group and 1.51 [1.09-2.06]mg/dl for the mTORi group (P = 0.917). Conclusion This retrospective study suggests that hypersensitized KTRs can receive safely a maintenance immunosuppression based on a combination of CNI with mTORi, without an increased risk of rejection.

Conversion from twice-daily everolimus to once-daily sirolimus in long-term stable liver transplant recipients

BackgroundAfter organ transplantation, strategies for simplifying the therapeutic regimen may improve adherence and prevent acute organ rejection and/or late graft loss. The present study aimed to evaluate the safety and efficacy of conversion from everolimus (EVR) twice daily to sirolimus (SIR) once daily in a large cohort of liver transplantation (LT) patients. MethodsWe included 108 LT patients with at least 12 months of post-transplant follow-up and no rejection episodes in the last year. Conversion was based on a 1:1 ratio (but eventually adapted to available formulations of SIR). ResultsThe median age at the time of conversion was 68.9 years (range: 26.1–83.6); 75.0% were men. The main indications for mTOR inhibitor use were renal failure (38.9%) and/or a history of malignancy (37.0%). Median conversion time after LT was 14.8 years (range: 2.3–31.5). The median dose of EVR and SIR (initially) was 1.50 mg/day (range: 0.5–4.5). The mean follow-up after conversion was 15.8±4.4 months. Median serum EVR/SIR trough levels before/after conversion were 3.85 ng/mL vs. 6.32 ng/mL (p < 0.05), i.e. a 1:1.64 ratio. At the end of follow-up after conversion, the median dose of SIR was 1.25 mg/day (range: 0.5–3.5), and the mean serum SIR trough level was 5.23 ng/mL; 9 patients (8.3%) had returned to EVR, because of side effects (mainly digestive), that resolved thereafter. No biopsy-proven acute rejection episode was observed. Finally, 87.1% of patients considered the conversion beneficial and the cost was reduced by 50.3%. ConclusionThe results of our study indicate that conversion from once-daily EVR to once-daily SIR in stable LT patients is safe, but needs dose adaptations and careful monitoring.

Survey on maintenance immunosuppressive therapy in patients undergoing solid organ transplantation: experiences from Italian transplant centers.

The post-organ transplant immunosuppressive therapy includes the administration of tacrolimus (Tac) or cyclosporine (CsA), along with antimetabolites (Antim) or mTOR inhibitors, with or without prednisone. A survey was conducted to investigate clinical experience regarding the use, efficacy, safety profile, and determinants of choice of maintenance immunosuppressive therapies. The questionnaire was sent to healthcare workers of 45 transplant centers specializing in kidney (K), liver (L), heart (H), and lung (P) transplants. Seventy-one responses were received from 15 Italian regions. The indicated first-choice therapy was Tac + Antim, except in the hepatic field where Tac monotherapy was favored. According to 44.1% of respondents, the first-choice therapy has changed over the last 15 years due to the replacement of CsA with Tac and increased use of mTOR inhibitors. Regarding the determinants of the index therapy, the choice of schemes to be applied depends mainly on international guidelines, previous experience, and internal protocols within the facility (80.3%; 54.9%; 50.7%, respectively). Compared to standard therapy, the criteria guiding the prescription of different therapies mainly involve the presence of comorbidities (K: 81.3%; L: 88.2%; H: 73.3%; P: 85.7%) and the evaluation of specific clinical parameters of the recipient. Additionally, the majority of respondents are in favor of using generic versions where available. The survey reveals dimensions not detectable by current healthcare administrative flows; such integrations provide a broader picture of the factors influencing the choice of post-transplant immunosuppressive therapeutic schemes.

Mammalian target of rapamycin inhibitors: A new-possible approach for in-utero medication therapy.

The mammalian/mechanistic target of rapamycin (mTOR) is a protein kinase that plays a crucial role in regulating cellular growth, metabolism, and survival. Although there is no absolute contraindication for the use of mTOR inhibitors during pregnancy, the specific fetal effects remain unknown. Available data from the past 2decades have examined the use of mTOR inhibitors during pregnancy in patients with solid organ transplantation, showing no clear link to fetal complications or structural abnormalities. Recently, a handful of case reports and series have described transplacental therapy of mTOR inhibitors to control symptomatic and complicated pathologies in the fetus. The effect of these agents includes a significant reduction in lesion size in the fetus and a reduced need for mechanical ventilation in neonates. In this context, we delve into the potential of mTOR inhibitors as in-utero therapy for fetal abnormalities, with a primary focus on lymphatic malformation (LM) and cardiac rhabdomyoma (CR). While preliminary reports underscore the efficacy of mTOR inhibitors for the treatment of fetal CR and fetal brain lesions associated with tuberous sclerosis complex, chylothorax, and LMs, additional investigation and clinical trials are essential to comprehensively assess the safety and efficacy of these medications.

Risk factors for incisional hernia after liver transplantation in the era of mammalian target of rapamycin inhibitors use: a retrospective study of living donor liver transplantation dominant center in Korea.

Incisional hernia (IH) is a common complication after liver transplantation (LT) with an incidence rate of 5% to 46%. This retrospective study aimed to evaluate the risk factors for IH development after LT in the era of mammalian target of rapamycin (mTOR) inhibitors use. Data on patients who underwent LT between 2015 and 2021 were retrospectively reviewed. The patients were divided into 2 groups (IH group and non-IH group) according to the postoperative occurrence of IH. We analyzed data from 878 patients during the study period, with 28 patients (3.2%) developing IH. According to multivariate analysis, body mass index exceeding 25 kg/m2 and the use of mTOR inhibitors within the first month after LT were the sole significant factors for both IH occurrence and the subsequent need for repair operations. Notably, a history of wound complications, a Model for End-stage Liver Disease score, and the timing of LT-whether conducted during regular hours or at night-did not emerge as significant risk factors for IH after LT. Our study reveals a higher incidence of IH among obese patients following LT, often requiring surgical repair, particularly in cases involving mTOR inhibitor usage within the initial month after LT. Consequently, it is crucial to exercise increased vigilance, especially in obese patients, and exercise caution when considering early mTOR inhibitor administration after LT.

Stabilization of Rapidly Progressive Cardiac Allograft Vasculopathy Using mTOR Inhibition After Heart Transplantation

Inhibition of the mammalian target of rapamycin (mTor) pathway after heart transplantation has been associated with reduced progression of coronary allograft vasculopathy (CAV). The application of low-dose mTOR inhibition in the setting of modern immunosuppression, including tacrolimus, remains an area of limited exploration. This retrospective study included patients who received heart transplantation between January 2009 and January 2019 and had baseline, 1-year and 2-3-year coronary angiography with intravascular ultrasound (IVUS). Intimal thickness in 5 segments along the left anterior descending artery was compared across imaging time points in patients who were transitioned to low-dose mTOR inhibitor (sirolimus) vs standard treatment with mycophenolate on a background of tacrolimus. Long-term adverse cardiovascular outcomes (revascularization, severe CAV, retransplant, and cardiovascular death) were also assessed. Among 216 patients (mean age 51.5 ± 11.9 years, 77.8% men, 80.1% white), 81 individuals (37.5%) were switched to mTOR inhibition. mTOR inhibition was associated with a reduction in intimal thickness by 0.05 mm (95% CI 0.02-0.07; P < 0.001). This reduction was driven by patients who met the criteria for rapidly progressive CAV 1-year post-transplant (0.12 mm; P = 0.016 for interaction). After a median follow-up of 8.6 (IQR 6.6-11) years, 40 patients had major adverse cardiovascular outcomes. The use of mTOR inhibitors was not significantly associated with cardiovascular outcomes (P = 0.669). Transitioning patients after heart transplantation to an immunosuppression regimen composed of low-dose mTOR inhibition and tacrolimus was associated with a lack of progression of CAV, particularly in those with rapidly progressive CAV at 1 year, but not with long-term cardiovascular outcomes.

Treatment of tuberous sclerosis complex manifestations in children with mTOR inhibitors.

Tuberous sclerosis complex (TSC) is a rare autosomal dominant genetic disorder that affects multiple organ systems. Mutations in the TSC1 and TSC2 genes result in the constitutive hyperactivation of the mammalian target of rapamycin (mTOR) pathway, contributing to the growth of benign tumors or hamartomas in various organs. Due to the implication of mTOR pathway dysregulation in the disease pathology, increasing evidence supports the use of mTOR inhibitors for treating multiple manifestations of TSC. In this study, we conducted a retrospective analysis of clinical findings and treatment data from 38 patients diagnosed with tuberous sclerosis who were followed up in the Pediatric Oncology Clinic between 2010 and 2020. We collected information on patients' ages, genders, affected sites, familial history, imaging findings, presence of tumors, and treatments. Among the patients, nine individuals with TSC manifestations were treated with mTOR inhibitors. Specifically, everolimus was successfully administered to five patients with inborn cardiac rhabdomyoma causing hemodynamic impairment. In addition, two patients with refractory seizures received everolimus in combination with anti-epileptic drugs. A patient with renal angiomyolipomas larger than 3cm was treated with everolimus, while a patient with extensive facial angiofibroma received topical sirolimus. All patients tolerated the mTOR inhibitors well, and the side effects were deemed acceptable. The utilization of mTOR inhibition in TSC is expected to become more prevalent in clinical practice, as current research is anticipated to provide a better understanding of the therapeutic roles of these treatments in TSC.

Enhanced Biohomogeneous Composite Membrane-Encapsulated Nanoplatform with Podocyte Targeting for Precise and Safe Treatment of Diabetic Nephropathy.

Diabetic nephropathy (DN), associated with high mobility and disability, is the leading cause of end-stage kidney disease worldwide. Dysfunction of the mammalian target of the rapamycin (mTOR) pathway and reactive oxygen species (ROS) activation in the glomeruli is the main hypnosis for DN progression. However, the use of mTOR inhibitors for DN treatment remains controversial. In this study, we built a multifunctional selective mechanistic target of rapamycin complex 1 (mTORC1) inhibiting nanoplatform (naming as ESC-HCM-B) that targets the release of mTOR and ROS inhibitors near podocytes, aiming to confirm whether combination therapy is an alternative method for DN treatment. The results showed that ESC-HCM-B achieved high drug loading because of the core mesoporous silica nanoparticles (MSNPs), and the enhanced biohomogeneous composite membrane endowed ESC-HCM-B with the characteristics of avoiding immune phagocytosis, automatic valve-type slow-release drug, and high stability. In vitro, the nanoplatform showed high efficiency in podocyte targeting but no significant cytotoxicity or apoptotic promotion. In particular, the quantum dots carried by ESC-HCM-B further amplified the effect of "nanoenzyme"; this mechanism reduced the ROS level in podocytes induced by high glucose, protected mitochondrial damage, and restored mitochondrial energy metabolism. In vivo, the nanoplatform specifically targeted the glomerular and podocyte regions of the kidney. After treatment, the nanoplatform significantly reduced urinary protein levels and delayed glomerulosclerosis in DN rats. This nanoplatform provides a safe and effective strategy for DN treatment.

Renal Dysfunction After Heart Transplant

Moderate or severe renal dysfunction (MSRD) is a frequent complication after heart transplantation. Strategies to delay progression and improve outcomes, such as renoprotective medications and timely referral to nephrology, remain important in providing care to heart transplant recipients with MSRD. What are chronic renal dysfunction's prevalence, risk factors, and optimal clinical management strategies in heart transplant recipients? This single-center, cross-sectional study examined patients who received a heart transplant from January 1, 2000, to June 30, 2011, and followed until December 31, 2011. Moderate or severe renal dysfunction was defined as a glomerular filtration rate of <60 mL/min/1.73 m2. The prevalence of MSRD among 195 heart transplant recipients was 60%. Variables associated with MSRD were female sex (odds ratio [OR]: 4.82; 95% CI, 1.72-13.54), greater age (OR: 1.10 per year; 95% CI, 1.06-1.14), time since transplant (OR: 1.0004 per year; 95% CI, 1.0001-1.0007), and mTOR inhibitor use (OR: 2.89; 95% CI, 1.24-6.71). Tacrolimus use (OR: 0.19; 95% CI, 0.05-0.71) and cyclosporine use (OR: 0.21; 95% CI, 0.05-0.80) were associated with patients without MSRD. Among patients with MSRD, 19.6% were referred to a nephrologist. Median eGFR remained stable at approximately 60 mL/min/1.73 m2 for 3 years after the study. Our results suggest that female sex, older age at transplant, and time since transplant are associated with MSRD in heart transplant recipients. Tacrolimus and cyclosporine use seemed renoprotective, but lower usage and increased mTOR inhibitor use may more likely indicate existing treatment patterns for patients with MSRD.

Rapamycin improves social and stereotypic behavior abnormalities induced by pre-mitotic neuronal subset specific Pten deletion.

The mechanistic target of rapamycin (mTOR) pathway is a signaling system integral to neural growth and migration. In both patients and rodent models, mutations to the phosphatase and tensin homolog gene (PTEN) on chromosome 10 results in hyperactivation of the mTOR pathway, as well as seizures, intellectual disabilities and autistic behaviors. Rapamycin, an inhibitor of mTOR, can reverse the epileptic phenotype of neural subset specific Pten knockout (NS-Pten KO) mice, but its impact on behavior is not known. To determine the behavioral effects of rapamycin, male and female NS-Pten KO and wildtype (WT) mice were assigned as controls or administered 10 mg/kg of rapamycin for 2 weeks followed by behavioral testing. Rapamycin improved social behavior in both genotypes and stereotypic behaviors in NS-Pten KO mice. Rapamycin treatment resulted in a reduction of several measures of activity in the open field test in both genotypes. Rapamycin did not reverse the reduced anxiety behavior in KO mice. These data show the potential clinical use of mTOR inhibitors by showing its administration can reduce the production of autistic-like behaviors in NS-Pten KO mice.

#5509 LOW DOSE THYMOGLOBULIN-BASILIXIMAB INDUCTION PROTOCOL ON INCIDENCE OF ACUTE REJECTION AND POSTTRANSPLANT NEOPLASIA: AN OBSERVATIONAL RETROSPECTIVE STUDY

Abstract Background and Aims Induction therapy plays a key role in the prevention of 1-year acute rejection in kidney transplantation. Several studies suggest that depleting drugs, including thymoglobulin (ATG), are superior to anti-CD25 antibodies in reducing the incidence of acute rejection. However, large retrospective investigations demonstrate a close and significant association between the use of depleting agents and the development of post-transplant neoplasia, in particular post-transplant lymphoproliferative disease. Thus, in the attempt to improve the risk/benefit profile of antibody therapy, we implemented an induction protocol based on low-dose ATG and anti-CD25 blocker basiliximab (Bas). The aim of the present study was to evaluate the efficacy and safety of this approach compared to standard dose ATG alone and basiliximab alone. Method This is a an observational, retrospective, single center study including 957 patients receiving a single kidney transplant the Gemelli kidney transplant center from January 2000 to February 2022 The primary efficacy outcome was biopsy proven acute rejection and the primary safety outcome was the development of post-transplant neoplasia. Patients in the ATG group received a cumulative dose of 7mg/kg in the first week after transplantation; patients in the Bas group were administered the anti-CD25 antibody at a dose of 20 mg before surgery and 20 mg 4 days after transplantation. Finally, patients in the ATG-Bas group received ATG at a cumulative concentration of 3mg/kg over the first 6 days after transplantation and Bas at a dose of 20 mg before surgery and 20 mg 4 days after transplantation. Results In our study population we evaluated 154 patients in the standard ATG group, 492 patients in the low AATG-Bas group and 311 patients in the Bas group. No statistical difference for age, mismatches, donor type, donor age, pre-transplant PRA was observed among groups. Use of mTOR inhibitors was more frequent in the standard ATG and low ATG-Bas groups compared to Bas group (80/154, 155/492, 76/311, respectively, p&amp;lt;0.001). We did not observe any significant difference in the use of other maintenance immunosuppressive drugs. Multivariate analysis (Cox model, including number of mismatches, presence of DSA at transplantation and use of mTOR inhibitors) demonstrated that only low ATG-Bas treatment (HR 0.509 95%CI 0.344-0.754, p&amp;lt;0.001), but not standard ATG (HR 0,819 95%CI 0.472-1.423, p = 0.5), was able to reduce the risk for acute rejection compared to Bas alone. On the other hand, multivariate analysis (Cox model including acute rejection, age, use of mTOR inhibitors) demonstrated that standard ATG induction (HR 1.677 95%CI 1.035-2.717, p = 0.03), but not low ATG-Bas (HR 1,324 95%CI 0,930-1,884, p = 0.1), significantly increased the risk for the development of post-transplant neoplasia compared to Bas alone. Conclusion In this retrospective analysis we demonstrated that low ATG-Bas protocol was the most effective treatment in preventing biopsy-proven acute rejection. In addition, on the contrary of standard ATG dose protocol it did not increase the risk of post-transplant neoplasia compared to Bas alone induction therapy.

Disparities in PI3K/mTOR inhibitor use, toxicities, and outcomes among patients with metastatic breast cancer.

6597 Background: Advances in breast cancer treatment have led to improvements in survival among patients with metastatic breast cancer (MBC). Nevertheless, Black patients and patients with lower socioeconomic status (SES) continue to bear a disproportionate mortality burden. Furthermore, because landmark trials for novel anticancer agents lacked racial diversity, their toxicity profile for minority patients remains uncertain. Our study examines the impact of race and other sociodemographic characteristics in the use and toxicity outcomes of PI3K and mTOR inhibitors (PI3K/mTORi). Methods: We conducted a retrospective analysis of EHR-derived data from the Flatiron Health Database (FHD). A dataset was constructed to include patients with hormone receptor-positive, HER2-negative MBC diagnosed between 1/1/2011 and 1/31/2022. Outcomes included PI3K/mTORi use, rates of hyperglycemia and dose reduction, and time on treatment. Multivariable logistic regression was used to evaluate factors associated with use and outcomes. Results: A total of 13,388 patients with MBC were included in our analysis, of which 2,620 (19.6%) received PI3K/mTORi (78.3% everolimus, 14.7% alpelisib, 6.9% both agents). Overall, 67.5% of all patients were categorized as White, 9.8% as Black/African-American (Black/AA); 18.9% were &gt;75 years old; 10.1% were treated at an academic site; 4.0% had Medicaid insurance. Insurance through Medicaid was associated with lower use of PI3K/mTORi compared to commercial insurance (15.6% vs 18.8%; OR: 0.76, 95% CI: 0.59-0.99, p=0.04), as was advanced age (10.9% for &gt;75 years old vs 22.9% for &lt;60 years old; OR: 0.68, 95% CI: 0.58-0.80, p&lt;0.001) and poorer performance status at diagnosis (15.1% for ECOG ≥2+ vs 22.9% for ECOG 0; OR: 0.84, CI: 0.72-0.98, p=0.03). Odds of PI3K/mTORi use were almost 50% higher for patients treated at an academic center (OR: 1.46, CI: 1.06-2.05, p=0.02). While Black/AA patient had lower rates of use than White patients (17.4% vs 20.1%), they had similar odds of receiving PI3K/mTORi on multivariable analysis (OR: 1.00, CI: 0.85-1.17, p&gt;0.9). Black/AA patients experienced higher rates of hyperglycemia on PI3K/mTORi than White patients (67.6% vs 52.5%). On multivariable analysis, odds of hyperglycemia were twice as high for Black/AA patients (OR: 2.1, CI: 1.33-3.35, p&lt;0.01). However, rates of dose reductions and time on PI3K/mTORi therapy did not differ significantly among White vs Black/AA patients. Conclusions: This analysis of real-world data suggests that lower SES is associated with decreased PI3K/mTORi use. Efforts to improve access to these life-prolonging agents are warranted. Of concern, we also found racial disparities in toxicity outcomes, with Black patients having twice the risk of hyperglycemia. Greater attention to the tolerability of novel agents in diverse populations is warranted.

Advances in the mTOR signaling pathway and its inhibitor rapamycin in epilepsy.

Epilepsy is one of the most common and serious brain syndromes and has adverse consequences on a patient's neurobiological, cognitive, psychological, and social wellbeing, thereby threatening their quality of life. Some patients with epilepsy experiencepoor treatment effects due to the unclear pathophysiological mechanisms of the syndrome. Dysregulation of the mammalian target of the rapamycin (mTOR) pathway is thought to play an important role in the onset and progression of some epilepsies. This review summarizes the role of the mTOR signaling pathway in the pathogenesis of epilepsy and the prospects for the use of mTOR inhibitors. The mTOR pathway functions as a vital mediator in epilepsy development through diverse mechanisms, indicating that the it has great potential as an effective target for epilepsy therapy. The excessive activation of mTOR signaling pathway leads to structural changes in neurons, inhibits autophagy, exacerbates neuron damage, affects mossy fiber sprouting, enhances neuronal excitability, increases neuroinflammation, and is closely associated with tau upregulation in epilepsy. A growing number of studies have demonstrated that mTOR inhibitors exhibit significant antiepileptic effects in both clinical applications and animal models. Specifically, rapamycin, a specific inhibitor of TOR, reduces the intensity and frequency of seizures. Clinical studies in patients with tuberous sclerosis complex have shown that rapamycin has the function of reducing seizures and improving this disease. Everolimus, a chemically modified derivative of rapamycin, has been approved as an added treatment to other antiepileptic medicines. Further explorations are needed to evaluate the therapeutic efficacy and application value of mTOR inhibitors in epilepsy. Targeting the mTOR signaling pathway provides a promising prospect for the treatment of epilepsy.

Effectiveness of Changing the Class of Molecularly Targeted Agent after Disease Progression during Initial Molecularly Targeted Therapy for Luminal Advanced/Metastatic Breast Cancer.

The emergence of molecularly targeted agents (MTAs) has altered the treatment landscape for hormone receptor-positive (HR+), human epidermal growth factor 2-negative (HER2-) advanced breast cancer (ABC) /metastatic breast cancer (MBC). Multiple guidelines recommend molecularly targeted therapy as first-line treatment for HR+/HER2- ABC/MBC. However, optimal treatment for disease progression during MTA therapy remains undetermined. This study evaluated the suitability of different MTA types for this patient subgroup. In this retrospective study, we analyzed the electronic health records of 56 patients with HR+/HER2- ABC/MBC receiving treatment with palbociclib, abemaciclib, or everolimus in our center between April 2014 and June 2021. Overall, 39, 14, and 35 regimens using palbociclib, abemaciclib, and everolimus, respectively, were identified. Three and 53 patients were premenopausal and postmenopausal, respectively. MTAs were included in the 1st-11th lines of treatment. Time to failure (TTF) was significantly different among the three MTAs. In contrast, TTF did not significantly differ among the 50 regimens that included CDK4/6 inhibitors, with/without prior mTOR inhibitor use, and the 35 regimens that included mTOR inhibitors, with/without prior CDK4/6 inhibitor use. The sequential use of different MTA classes did not affect the TTF of another MTA. mTOR inhibitor + exemestane is a favorable treatment option after CDK4/6 inhibitor + hormone therapy, and CDK4/6 inhibitor + hormone therapy is suitable for patients previously treated with mTOR inhibitor + exemestane. Although this study was retrospective and conducted at a single center, the present findings are useful for treatment selection in clinical practice.

Effect of mTOR Inhibitors in Epilepsy Treatment in Children with Tuberous Sclerosis Complex Under 2 Years of Age

Mechanistic target of rapamycin (mTOR) inhibitors sirolimus and everolimus are an effective therapy for subependymal giant cell astrocytomas, cardiac rhabdomyomas, renal angiomyolipomas, and lymphangioleiomyomatosis associated with tuberous sclerosis complex (TSC). Everolimus was recently approved in the EU and the USA for the treatment of refractory focal-onset seizures. Despite frequent use of mTOR inhibitors, there are only a few studies on their effect on epilepsy control in children under 2years of age. This study aims to assess the effect of adjunctive mTOR inhibitor treatment on seizure frequency in this age group. We performed retrospective data analysis of medical records of patients with TSC who initiated sirolimus or everolimus under the age of 2years. Participants' antiseizure medication was adjusted according to their epilepsy control independently from mTOR inhibitor administration. The data was assessed separately for patients treated with mTOR inhibitors before and after the onset of seizures. We also compared the treatment group with a matched control group. The follow-up duration was up to 24months. Twenty-one patients with TSC from two clinical centers were included in the study. Nine participants had no history of seizures before mTOR inhibitor initiation. Twelve reported active epilepsy in the month prior to treatment initiation. Most patients treated preventively with mTOR inhibitors did not report active epilepsy at the end of their follow-up. In the second group, the mean frequency of seizures decreased with time. According to the comparative analysis, seizure control was better in the groups treated with mTOR inhibitors. Patients with TSC treated with mTOR inhibitors demonstrated better seizure control than individuals without this treatment. Adjunctive pharmacotherapy with mTOR inhibitors appears to have a beneficial effect on epilepsy outcome in young children. Further prospective clinical trials should be conducted to determine the efficacy of mTOR inhibitors on epilepsy in patients with TSC under the age of 2years.