BACKGROUND: The 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.
RESULTS: In 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)].
CONCLUSIONS: Vaccination 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.

BACKGROUND: Although lung transplantation (LTx) is the last resort for patients with end-stage lymphangioleiomyomatosis (LAM), the high waitlist mortality is a source of concern in Japan. Discontinuation of mechanistic target of rapamycin (mTOR) inhibitors prior to LTx is recommended due to the incidence of severe adverse events. Therefore, we hypothesized that mTOR inhibitors may affect the mortality of patients with LAM on the LTx waitlist.
METHODS: We retrospectively compared the characteristics of consecutive patients with LAM on the LTx waitlist who were and were not receiving mTOR inhibitors.
RESULTS: Twenty-nine consecutive patients with LAM who listed our center between January 2004 and December 2021 were selected from the database and enrolled in the present study. Seventeen patients (58.6%) were receiving a mTOR inhibitor, sirolimus (treatment group). During a median listing period of 1277 days, 12 patients (41.4%) were hospitalized, six patients (20.7%) died from disease before LTx, and 15 patients underwent LTx. Among the deceased patients, four patients (66.6%) had pneumothoraces. The waitlist mortality in the treatment group was significantly lower than that in the non-treatment group (p = 0.03). Among the six patients who discontinued sirolimus in the treatment group, four patients (66.6%) were hospitalized with respiratory complications after the discontinuation of sirolimus. No mTOR inhibitor-related complications arose in the treatment group undergoing LTx (n = 7), including those on a reduced sirolimus dose.
CONCLUSIONS: Administration of an mTOR inhibitor until LTx may decrease waitlist mortality. Due to life-threatening events after discontinuing sirolimus pre-LTx, a reduced dose until LTx is permissible.

OBJECTIVE: Despite significant progress in biomedical research, the rate of success in oncology drug development remains inferior to that of other therapeutic fields. Mechanistic models provide comprehensive understanding of the therapeutic effects of drugs, which is crucial for designing effective clinical trials. This study was performed to acquire a better understanding of PI3K-AKT-TOR pathway modulation and preclinical to clinical translational bridging for a specific compound, apitolisib (PI3K/mTOR inhibitor), by developing integrated mechanistic models.
METHODS: Integrated pharmacokinetic (PK)-pharmacodynamic (PD)-efficacy models were developed for xenografts bearing human renal cell adenocarcinoma and for patients with solid tumors (phase 1 studies) to characterize relationships between exposure of apitolisib, modulation of the phosphorylated Akt (pAkt) biomarker triggered by inhibition of the PI3K-AKT-mTOR pathway, and tumor response.
RESULTS: Both clinical and preclinical integrated models show a steep sigmoid curve linking pAkt inhibition to tumor growth inhibition and quantified that a minimum of 35-45% pAkt modulation is required for tumor shrinkage in patients, based on platelet-rich plasma surrogate matrix and in xenografts based on tumor tissue matrix. Based on this relationship between targeted pAkt modulation and tumor shrinkage rate, it appeared that a constant pAkt inhibition of 61% and 65%, respectively, would be necessary to achieve tumor stasis in xenografts and patients.
CONCLUSIONS: These results help when it comes to evaluating the translatability of the preclinical analysis to the clinical target, and provide information that will enhance the value of future preclinical translational dose-finding and dose-optimization studies to accelerate clinical drug development.
BACKGROUND: ClinicalTrials.gov NCT00854152 and NCT00854126.

Systemic mastocytosis (SM) corresponds to a rare and heterogeneous spectrum of diseases characterized by the accumulation of atypical mast cells (MCs). Advanced mastocytosis (Adv-SM) is associated with poor survival; in contrast, patients with non-advanced SM (non-Adv-SM) usually have a normal life expectancy but may experience poor quality of life. Despite recent therapeutic progress including tyrosine kinase inhibitors, new treatment options are needed for refractory and/or intolerant patients with both severely symptomatic and Adv-SM. In vitro, the mTOR pathway is activated in MCs from patients bearing the KIT D816V mutation. Furthermore, rapamycin induces the apoptosis of KIT D816V MCs selectively. In this nationwide study, we report the outcomes of patients diagnosed with SM and treated with a mammalian target of rapamycin inhibitor (imTOR) within the French National Reference Center for mastocytosis (CEREMAST). All patients registered were relapsing, treatment-refractory, or ineligible for other cytoreductive therapy. Non-Adv-SM patients received imTOR as a monotherapy (rapamycin/everolimus), and Adv-SM patients received imTOR as a monotherapy or in combination with cytarabine. The objective response rate (ORR) in non-Adv-SM was 60% (partial response in 40% and major response in 20%), including reductions in skin involvement, mediator release symptoms, and serum tryptase. In the Adv-SM group, the ORR was 20% (including one major response and one partial response, both in patients with a KIT D816V mutation), which enabled a successful bridge to allogeneic stem cell transplantation in one patient. Our results suggest that imTOR treatment has potential benefits in patients with SM harboring a KIT D816V mutation.

UNASSIGNED: Sirolimus has emerged as a safe and effective treatment for complicated lymphatic malformations (LMs). We aim to prove the effectiveness and safety of sirolimus as a therapeutic option for patients with complicated LMs.
UNASSIGNED: Fifty-eight patients with complicated LMs treated with sirolimus for at least 6 months at multicenter between July 2018 and January 2023 were enrolled. All patients were administered oral sirolimus starting at 0.8 mg/m2 every 12 hours, with target serum concentration levels of 8-15 ng/mL. Evaluation for clinical symptoms and LMs volume on MRI were reviewed to assess treatment response and toxicities. Evaluation of disease response was divided into 3 values: complete response, partial response (significant, moderate, and modest), and progressive disease.
UNASSIGNED: The median age at the initiation of sirolimus treatment was 6.0 years (range, 1 month-26.7 years). The median duration of treatment was 2.0 years (range, 6 months-4.4 years). The most common lesions were head and neck (25 of 58, 43.1%). Forty-six patients (79.3%) demonstrated a reduction in LMs volume on MRI or improvement of clinical symptoms including 2 complete responses. The young age group and the patients who underwent few prior therapies showed better responses. None of the patients had toxicities attributable to sirolimus with a Common Terminology Criteria for Adverse Events grade of ≥3.
UNASSIGNED: Oral sirolimus treatment brought a successful outcome without severe adverse effects. It could be the first-line therapy, especially for the young age group of complicated LMs, and an additional option for refractory lesions that did not respond to conventional treatment.

OBJECTIVE: We investigated the efficacy of a predetermined protocol that consisted of immunosuppressive drug reduction/withdrawal and intravenous immunoglobulin administration for the treatment of polyoma BK virus nephropathy.
METHODS: Patients with biopsy-proven polyoma BK virus nephropathy received a treatment regimen based on discontinuation of both calcineurin inhibitors and antiproliferative agents and switching to mTOR inhibitors accompanied by intravenous immunoglobulin administration.
RESULTS: Our study included 508 patients, with polyoma BK viremia detected in 80 patients. The mean age was 45.3 ± 9.5 years (range, 18-71 y), 64% were male, and mean follow-up was 37 ± 21 months (6-94 mo). All 16 patients who developed polyoma BK virus nephropathy and 9 patients who had highgrade polyoma BK viremia without nephropathy received intravenous immunoglobulin treatment. Compared with patients with viremia, patients with polyoma BK virus nephropathy had significantly higher rates of graft loss due to rejection (18.8% vs 1.6%; P = .024) and all-cause graft loss (31.2% vs 6.3%; P = .014). Histopathologically, viral inclusion bodies disappeared and SV40 became negative after treatment in all 13 patients who underwent protocol biopsies. Unfortunately, histopathologically complete recovery without chronic tubular and interstitial tissue damage was achieved in only 4 patients after treatment. In addition, 3 patients lost their grafts due to acute antibody-mediated or mixed-type rejection (18.8%).
CONCLUSIONS: In patients with polyoma BK virus nephropathy, clearance of viremia and SV40 should not be the sole outcomes to obtain. Aggressive reductions in maintenance immunosuppression and switching to double-drug therapy combined with high-dose intravenous immunoglobulin leads to high rates of graft loss/rejection and sequalae of chronic histological changes.

UNASSIGNED: 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.
UNASSIGNED: 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.
UNASSIGNED: 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.
UNASSIGNED: 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.

S1 and S2, two structurally similar quinazoline derivatives, are novel anticancer drugs targeting the PI3K/AKT/mTOR signaling pathway channel. However, their pharmacokinetic and tissue distribution characteristics are unknown, which has hindered further development and in-depth studies. In this study, a simple, rapid and sensitive method using high performance liquid chromatography was established and validated to quantitatively study the pharmacokinetics and tissue distribution profiles of S1 and S2 in rats following intravenous injection. The results indicated that after intravenous injection, the elimination of S1 and S2 fit the two-compartment model and linear pharmacokinetics characteristics were observed. Furthermore, S1 and S2 were widely distributed and found in high concentrations in liver and kidney tissues and a small proportion of S1 and S2 could cross the blood-brain barrier and be distributed in the brain. The current findings will contribute to interpretation and understanding the relationship between dosage and pharmacodynamic effects of S1 and S2.

Kidney transplant recipients are at an increased risk of fractures, and targeted preventive strategies are needed. Therefore, in this retrospective cohort study, we investigated a large population-based cohort to identify the transplant recipient-specific risk factors for fractures in Taiwanese kidney transplant recipients.
We conducted a retrospective cohort study using the National Health Insurance Research Database. Patients who underwent renal transplantation between 2003 and 2015 were identified and followed until December 31, 2015, to observe the development of fractures. Variables associated with the development of post-transplant fractures were identified by calculating hazard ratios in a Cox regression model.
5,309 renal transplant recipients were identified, of whom 553 (10.4%) were diagnosed with post-transplant fractures. Independent predictors of post-transplant fractures included an age at transplant ≥65 years (p < 0.001), female sex (p < 0.001), fractures within 3 years prior to transplantation (p < 0.001), and diabetes mellitus (p < 0.001). In addition, daily prednisolone doses >2.9–5.3 mg/day (p < 0.001), >5.3–8.7 mg/day (p < 0.001), and >8.7 mg/day (p < 0.001) were also independent predictors of post-transplant fractures. Conversely, the use of peritoneal dialysis before renal transplantation (p = 0.021), hypertension (p = 0.005), and the use of tacrolimus (p < 0.001), azathioprine (p = 0.006), mycophenolate mofetil/mycophenolic acid (p = 0.002), mTOR inhibitors (p = 0.004), and calcium supplements (p = 0.009) were inversely correlated with post-transplant fractures.
We recommend minimizing daily glucocorticoids as early and as far as possible in conjunction with immunosuppressive regimens such as tacrolimus, azathioprine, mycophenolate mofetil/mycophenolic acid, mTOR inhibitors, and calcium supplements, especially in older female recipients and in recipients with diabetes and a history of prior fractures.

Data on calcineurin-inhibitor (CNI) free immunosuppression after lung transplantation (LTx) are limited. Aim of this study was to investigate CNI-free immunosuppression using mechanistic target of rapamycin (mTOR) inhibitors.
This retrospective analysis was performed at a single center. Adult patients after LTx without CNI during the follow-up period were included. Outcome was compared to those LTx patients with malignancy who continued CNI.
Among 2,099 patients in follow-up, fifty-one (2.4%) were converted median 6.2 years after LTx to a CNI-free regimen combining mTOR inhibitors with prednisolone and an antimetabolite, two patients were switched to mTOR inhibitors with prednisolone only. In 25 patients, malignancies without curative treatment options were the reason of the conversion, with a 1-year survival of 36%. The remaining patients had a 1-year survival of 100%. Most common non-malignant indication was neurological complications (n = 9). Fifteen patients were re-converted to a CNI-based regimen. The median duration of CNI-free immunosuppression was 338 days. No acute rejections were detected in 7 patients with follow-up biopsies. In multivariate analysis, CNI-free immunosuppression were not associated with improved survival after malignancy. The majority of patients with neurological diseases improved 12 months after conversion. Glomerular filtration rate increased by median 5 (25 and 75% percentiles -6; +18) ml/min/1.73 m2.
mTOR inhibitor based CNI-free immunosuppression may be safely performed in selected patients after LTx. This approach was not associated with improved survival in patients with malignancy. Significant functional improvements were observed in patients with neurological diseases.