Integrated genomic/epigenomic analysis stratifies subtypes of clear cell ovarian carcinoma, highlighting their cellular origin.

The cellular origin of clear cell ovarian carcinoma (CCOC), a major histological subtype of ovarian carcinoma remains elusive. Here, we explored the candidate cellular origin and identify molecular subtypes using integrated genomic/epigenomic analysis. We performed whole exome-sequencing, microarray, and DNA methylation array in 78 CCOC samples according to the original diagnosis. The findings revealed that ARID1A and/or PIK3CA mutations were mutually exclusive with DNA repair related genes, including TP53, BRCA1, and ATM. Clustering of CCOC and other ovarian carcinomas (n = 270) with normal tissues from the fallopian tube, ovarian surface epithelium, endometrial epithelium, and pelvic peritoneum mesothelium (PPM) in a methylation array showed that major CCOC subtypes (with ARID1A and/or PIK3CA mutations) were associated with the PPM-lile cluster (n = 64). This cluster was sub-divided into three clusters: (1) mismatch repair (MMR) deficient with tumor mutational burden-high (n = 2), (2) alteration of ARID1A (n = 51), and (3) ARID1A wild-type (n = 11). The remaining samples (n = 14) were subdivided into (4) ovarian surface epithelium-like (n = 11) and (5) fallopian tube-like (considered as high-grade serous histotype; n = 3). Among these, subtypes (1-3) and others (4 and 5) were found to be associated with immunoreactive signatures and epithelial-mesenchymal transition, respectively. These results contribute to the stratification of CCOC into biological subtypes.

Evaluating the specific STAT3 inhibitor YHO-1701 in ovarian cancer cell lines and patient-derived cell models: efficacy, mechanisms, and therapeutic potential.

OBJECTIVE: Signal transducer and activator of transcription 3 (STAT3) plays key roles in regulating cancer cell proliferation, survival, and metastasis. We aimed to determine the effects of YHO-1701, an oral STAT3 inhibitor, in ovarian cancer (OC). METHODS: We evaluated the impact of YHO-1701 on cell growth in patient-derived cells (PDCs) and OC cell lines using standard cell proliferation assays. Spheroid models derived from PDCs were assessed using three-dimensional (3D) cell viability assays. Antitumor activity was performed in SKOV3 xenograft mice treated orally administrated YHO-1701 with 20 mg/kg. Changes in STAT3 signaling were analyzed by western blotting. The molecular mechanisms of STAT3 inhibition were investigated by sequencing RNA and analyzing pathways in the SKOV3 using a small interfering RNA targeting STAT3 (STAT3 siRNA) and YHO-1701. RESULTS: YHO-1701 inhibited the growth of OC cell lines by preventing STAT3 dimerization and decreasing the expression of its downstream signaling molecule, survivin. The growth of PDCs and spheroids obtained from patients with primary and recurrent OCs was significantly inhibited. Antitumor effect was observed in the SKOV3 xenograft mice with YHO-1701. YHO-1701 induced apoptosis in OC cells. Additionally, p53 and/or MAPK signaling pathways were upregulated in SKOV3 cells incubated with YHO-1701 and in those with STAT3 siRNA. CONCLUSION: Our results showed that YHO-1701 suppressed cell growth in PDCs of OC, accompanied by survivin inhibition, and a decrease in the number of peritoneal metastasis in the mice by YHO-1701, compared with those treated with control. Therefore, YHO-1701 could be a promising candidate agent for treating OC.

Antibody-Drug Conjugates: The New Treatment Approaches for Ovarian Cancer.

Ovarian cancer (OC), accounting for approximately 200,000 deaths worldwide annually, is a heterogeneous disease showing major differences in terms of its incidence, tumor behavior, and outcomes across histological subtypes. In OC, primary chemotherapy, paclitaxel carboplatin, bevacizumab, and PARP inhibitors have shown prolonged progression-free survival and a favorable overall response rate compared to conventional treatments. However, treatment options for platinum-resistant recurrence cases are limited, with no effective therapies that significantly prolong the prognosis. Recently, mirvetuximab soravtansine, an alpha-folate receptor (FRα)-targeted antibody-drug conjugate (ADC), was approved by the US Food and Drug Administration for patients with FRα-positive recurrent epithelial OC (EOC). This approval was based on a Phase II study, which demonstrated its efficacy in such patients. ADCs comprise an antibody, a linker, and a payload, representing new concept agents without precedence. Advanced clinical studies are developing ADCs for patients with OC, targeting solid tumors such as gynecologic cancer. Ongoing clinical trials are evaluating ADCs targeting FRα and human epidermal growth factor receptor 2, trophoblast cell surface antigen-2, sodium-dependent phosphate transport protein 2B, and cadherin-6 in Phase II/III studies. In this review, we summarize the existing evidence supporting the use of ADCs in OC, discuss ongoing clinical trials and preclinical studies, and explore the potential of these innovative agents to address the challenges in OC treatment.

Intestinal ultrasound for intestinal Behçet disease reflects endoscopic activity and histopathological findings.

BACKGROUND/AIMS: Intestinal Behçet disease is typically associated with ileocecal punched-out ulcers and significant morbidity and mortality. Intestinal ultrasound is a noninvasive imaging technique for disease monitoring. However, no previous reports have compared intestinal ultrasound with endoscopic ulcer activity or histopathological findings for intestinal Behçet disease. We evaluated the usefulness of intestinal ultrasound for assessing the activity of ileocecal ulcers in intestinal Behçet disease. METHODS: We retrospectively compared intestinal ultrasound findings with 73 corresponding endoscopic images and 6 resected specimens. The intestinal ultrasound findings were assessed for 7 parameters (bowel wall thickness, vascularity [evaluated using the modified Limberg score with color Doppler], bowel wall stratification, white-plaque sign [strong hyperechogenic lines or spots], mesenteric lymphadenopathy, extramural phlegmons, and fistulas), and endoscopic ulcer activity was classified into active, healing, and scar stages. Histopathological findings were evaluated by consensus among experienced pathologists. RESULTS: Bowel wall thickness (P< 0.001), vascularity (P< 0.001), loss of bowel wall stratification (P= 0.015), and white-plague sign (P= 0.013) were significantly exacerbated in the endoscopic active ulcer stage. Receiver operating characteristic curve analysis revealed that a bowel wall thickness of > 5.5 mm (sensitivity 89.7%, specificity 85.3%) was potentially useful for detecting active lesions. When compared with histopathological findings, an increase in bowel wall thickness reflected the ulcer marginal ridge, and the white-plaque sign reflected the ulcer bottom. CONCLUSIONS: Intestinal ultrasound is useful for monitoring intestinal ulcer activity in intestinal Behçet disease.

Hepatitis B surface antigen (HBsAg) glycan isomer is predictive of HBsAg seroclearance in patients with chronic hepatitis B.

AIM: Measurement of O-glycosylated middle hepatitis B surface antigen (HBsAg glycan isomer, HBsAgGi) has been developed to quantify hepatitis B virus (HBV) infectious virions and distinguish them from subviral particles. This study aimed to evaluate the association between serum HBsAg seroclearance and serum HBV virions measured by HBsAgGi in patients with chronic hepatitis B (CHB). METHODS: Serum HBsAgGi levels were quantified in 232 treatment-naïve patients with CHB genotype C. Cox proportional hazards analysis was used to calculate hazard ratios (HRs) for factors associated with HBsAg seroclearance. RESULTS: Baseline HBsAgGi levels showed significant differences among HBV phenotypes. During a median follow-up period of 7.4 years, 22 of the 232 patients achieved HBsAg seroclearance. Multivariate analysis demonstrated that quantitative HBsAg, nucleoside/nucleotide analog therapy during the follow-up period, and HBsAgGi levels were independent predictors of seroclearance. The adjusted HR indicated that the HBsAg seroclearance probability in patients with low HBsAgGi (≤3.5log ng/mL) was over five times higher than that in patients with high HBsAgGi. Kaplan-Meier analysis indicated that the 10-year probabilities of HBsAg seroclearance were 21.0% and 3.0% in patients with low and high HBsAgGi levels, respectively (p < 0.001), and that patients with high HBsAgGi levels showed low seroclearance probabilities irrespective of the other predictors. CONCLUSION: Serum HBV infectious virion levels, measured using HBsAgGi, may be a novel predictor of HBsAg seroclearance.

Comparative Study of Postmortem MRI and Pathological Findings in Malignant Brain Tumors.

This study compared magnetic resonance imaging (MRI) findings of postmortem brain specimens with neuropathological findings to evaluate the value of postmortem MRI. Postmortem MRI was performed on five formalin-fixed whole brains with malignant tumors. Postmortem T2-weighted images detected all neuropathological abnormalities as high-signal regions but also showed histological tumor invasion in areas without edema. Tumor lesions with high necrosis and edema showed high signal intensity on T2-weighted images; in three cases, lesion enlargement was detected on the final prenatal imaging and postmortem MRI. Disease progression immediately before death may have contributed to this difference. In conclusion, the correlation between MRI and neuropathological findings facilitates understanding of the mechanisms responsible for MRI abnormalities. Increased free water due to edema, necrosis, and brain tissue injury can explain the increased signal intensity observed on T2-weighted images. Postmortem MRI may contribute to effective pathology by identifying subtle abnormalities prior to brain dissection.

Delayed Pseudoprogression in Glioblastoma Patients Treated With Tumor-Treating Fields.

Tumor-treating fields (TTFields) is an established treatment modality for glioblastoma. False progression to chemoradiation is a known problem in patients with glioblastoma multiforme (GBM), with most cases occurring within three months of radiation therapy. In this report, we present two cases of delayed pseudoprogression caused by TTFields. Two patients with GBM who received TTFields showed signs of radiographic progression six months after the completion of radiation therapy. Patient 1 was a 37-year-old female with a glioblastoma in the right temporal lobe. Patient 2 was a 70-year-old male with glioblastoma in the left temporal lobe. Both patients received radiation therapy, followed by temozolomide (TMZ) maintenance therapy and TTFields. Patient 1 underwent a second resection; however, the pathology revealed only a treatment effect, and the final diagnosis was a pseudoprogression. In Case 2, the disease resolved with steroid therapy alone. In both patients, the lesions appeared later than during the typical pseudoprogression period. A recent study reported that TTFields increase the permeability of the plasma cell membrane, which may result in further leakage of gadolinium into the extracellular lumen. Further studies are needed to better characterize delayed pseudoprogression and improve treatment outcomes.

The real-world data of immune-checkpoint inhibitor combination therapy for unresectable or metastatic esophageal cancer: a multi-institutional cohort study.

BACKGROUND: The real-world efficacy, feasibility, and prognostic factors of immune-checkpoint inhibitor combination therapy for unresectable or metastatic esophageal cancer are not fully established. METHODS: This multi-institutional retrospective cohort study evaluated 71 consecutive patients treated with immune-checkpoint inhibitor combination therapy for esophageal cancer between March 2021 and December 2022. We assessed tumor response, safety, and long-term survival. RESULTS: In patients with measurable lesions, the response rate was 58%, and the disease control rate for all enrolled patients was 80%. Five patients (7.0%) underwent successful conversion surgery. Grade 3 or higher immune-related adverse events occurred in 13% of patients, and one patient (1.4%) died due to cholangitis. Median progression-free survival was 9.7 (95% confidence interval: 6.5-not reached). C-reactive protein levels and performance status were identified as significant predictors of progression-free survival through Cox proportional hazards analysis. CONCLUSIONS: Immune-checkpoint inhibitor combination therapy for esophageal cancer demonstrated comparable tumor response, safety, and long-term survival to previous randomized clinical trials. Patients with good performance status and low C-reactive protein levels may be suitable candidates for this treatment.

Evaluation of Treatment Strategies for Male Prolactin-Secreting Pituitary Neuroendocrine Tumors.

Prolactin-secreting pituitary neuroendocrine tumors (PitNETs) are more common in women. Male patients may also have few symptoms and have macroadenomas extending outside the sella turcica. This study aimed to report the results of cabergoline treatment in male patients with prolactin-secreting PitNET. The study included nine male patients aged 26-65 years (median, 46 years) diagnosed with prolactin-secreting PitNETs. The age at onset, prolactin values, tumor size, symptoms, and treatment were assessed. The mean prolactin value at the initial presentation was 2734.6 ng/mL, and the mean maximum tumor diameter was 40.4 mm. Visual field disturbance was the most common symptom (44.4%), followed by headaches (33.3%), asymptomatic symptoms (11.1%), and galactorrhea (11.1%). Eight patients responded to cabergoline treatment with normalization of prolactin levels and tumor shrinkage. One patient did not respond to the cabergoline treatment and required surgical intervention. There were no cases of cerebrospinal fluid leakage. Cabergoline was found to be an effective treatment for male prolactin-secreting PitNETs.

[A Case of Desmoid-Type Fibromatosis of the Mesentery of Small Intestine].

Desmoid-type fibromatosis is a relatively rare disease, often associated with familial adenomatous polyposis and a history of abdominal surgery. A 43-year-old male patient presented with abdominal pain and contrast-enhanced CT showed a mass in the lower abdomen. The mass was a 4×4×3 cm white, dense tumor with a wreath-like arrangement of eosinophilic spindle-shaped cells. Immunostaining showed KIT(-), CD34(-), desmin(-), ß-catenin(+), SMA(few+), and the diagnosis was desmoid-type fibrosis. Six months after surgery, there was no apparent recurrence.

A single-institution retrospective exploratory analysis on the effectiveness and safety of lenvatinib plus pembrolizumab for advanced endometrial cancer: insights from ProMisE molecular classification system.

BACKGROUND: The Proactive Molecular Risk Classifier for Endometrial Cancer has identified four risk groups for the prognosis of endometrial cancer. Lenvatinib plus pembrolizumab was recently approved as a second-line treatment for unresectable endometrial cancer, but reports in clinical practice are lacking. The relationship between the efficacy of lenvatinib/pembrolizumab and Proactive Molecular Risk Classifier for Endometrial Cancer classification is unclear. METHODS: This single-centre retrospective study included patients who underwent lenvatinib/pembrolizumab therapy at Iwate Medical University Hospital between January 2022 and March 2023. Formalin-fixed paraffin-embedded specimens obtained from patients before treatment were collected and classified into the mismatch repair-deficient, p53 abnormal and no specific molecular profile subtypes using immunohistochemistry. The response rate, progression-free survival and adverse events were evaluated using electronic medical records. The study was approved by the hospital's ethics committee (approval number: MH2022-093). RESULTS: This study enrolled 20 patients, who underwent a median follow-up of 17.8 months (95% confidence interval: 16.6-18.9). The best overall response rate was 60.0% (36.1-80.9), and the median progression-free survival was 11.6 months (2.9-20.3). The median progression-free survival in the p53 abnormal group (n = 9) was 3.4 months (3.0-3.8); however, progression-free survival did not reach the median (P < 0.001) in the mismatch repair-deficient/no specific molecular profile group (n = 11). Symptomatic immune-related adverse events (except hypothyroidism) occurred in 4/20 (25.0%) patients, and partial responses were observed in all cases. No treatment-related deaths occurred. CONCLUSION: The p53abn group in the Proactive Molecular Risk Classifier for Endometrial Cancer classification has a poor prognosis even after treatment with lenvatinib/pembrolizumab.

What can cause cancer patients to attempt suicide? Thiamine deficiency mimicking the symptoms of major depressive disorder.

OBJECTIVES: Thiamine deficiency (TD) presents with various physical and psychiatric symptoms, but no cases with depression-like symptoms have been reported. METHODS: We report a patient with cancer who appeared to attempt suicide as a consequence of depressive mood likely related to TD. RESULTS: The patient was a 58-year-old woman diagnosed with recurrent endometrial cancer, with lung metastasis and pelvic dissemination. The patient apparently attempted suicide was referred to the psycho-oncology department. At the time of the examination, major depressive disorder was suspected based on her mental symptoms, but when thiamine was administered intravenously in response to her poor dietary intake, her palpitations, dyspnea, anorexia, and insomnia improved, and her suicidal ideation disappeared at her reexamination 1 hour later after thiamine administration. SIGNIFICANCE OF RESULTS: It is likely that the observed palpitations, dyspnea, anorexia, and insomnia, as well as the severe depression and the attempted suicide, which were thought to be physical symptoms associated with depression, were actually related to TD. Suicidal ideation and attempted suicide are conspicuous as psychiatric symptoms. However, in such cases, rather than simply starting treatment for depression, it is necessary to consider reversible TD as a cause of these symptoms and perform differential diagnosis to confirm the physical illness.

Retrograde Transcaval Obliteration for Refractory Hepatic Encephalopathy with Multiple Intrahepatic Portosystemic Venous Shunts.

An intrahepatic portosystemic venous shunt (IPSVS) is a rare vascular abnormality, particularly in patients without cirrhosis. An 80-year-old woman without a history of chronic liver disease was admitted to our hospital with hepatic encephalopathy. Computed tomography revealed multiple IPSVSs with two large shunts in segment 6. As conservative therapies were insufficient for treating the symptoms and reducing ammonia levels, retrograde transcaval obliteration was performed. The two large shunts were successfully embolized using detachable coils. Consequently, hyperammonemia and hepatic encephalopathy dramatically improved, and the triphasic wave patterns of the electroencephalogram disappeared. Retrograde transcaval obliteration may be effective for refractory hepatic encephalopathy with IPSVS.

Small Intestinal Arteriovenous Malformation Treated by Double-balloon Endoscopy.

A 42-year-old man was referred to our hospital because of anemia. The patient underwent gastroscopy and colonoscopy, but no bleeding site was detected. Abdominal contrast-enhanced computed tomography (CT) showed vascular dilatation along the wall of the small intestine. Small bowel capsule endoscopy and antegrade double-balloon endoscopy (DBE) were performed, and the patient was diagnosed with a small intestinal arteriovenous malformation (AVM). The AVM was clipped using DBE. After clipping, abdominal contrast-enhanced CT and small bowel angiography revealed the disappearance of the AVM. DBE may be a viable therapeutic option, helping avoid surgery and its associated risks.

Quantitation and characterization of glucosylsphingosine in cerebrospinal fluid (CSF), plasma, and brain of monkey model with Gaucher disease.

Treatment with conduritol-ß-epoxide (CBE) in preclinical species is expected to be a powerful approach to generate animal models of Gaucher disease (GD) and Parkinson's disease associated with heterozygous mutations in Glucocerebrosidase (GBA-PD). However, it is not fully elucidated how quantitatively the change in glucosylsphingosine (GlcSph) levels in cerebrospinal fluid (CSF) correlates with that in the brain, which is expected to be clinically informative. Herein, we aimed to investigate the correlation with successfully quantified GlcSph in monkey CSF by developing highly sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods. The GlcSph in normal monkey CSF was 0.635 ± 0.177 pg/mL at baseline and increased by CBE treatment at 3 mg/kg daily for five days up to a moderate level, comparable to that in GD patients. The balance between GlcSph and galactosylsphingosine (GalSph) in the CSF matched that in the brain rather than plasma. In addition, GlcSph in the CSF was increased, accompanied by that in the brain at a dose of 3 mg/kg daily. These results indicate that GlcSph in the CSF is worth evaluating for concentration changes in the brain. Thus, this model can be useful for evaluating GBA-related diseases such as GD and GBA-PD.

Ramucirumab Plus Paclitaxel as a Second-line Chemotherapy in Older Adults With Advanced Gastric Cancer (YCOG1601).

BACKGROUND/AIM: Ramucirumab plus paclitaxel has been widely used as a second-line chemotherapy for treating advanced gastric cancer. However, the real-world data of this regimen for older patients with gastric cancer (GC) remains unrevealed. The aim of this study was to clarify the feasibility and efficacy of this regimen for older patients with GC in a single-arm, phase II study. PATIENTS AND METHODS: Patients aged ≥70 years having unresectable or recurrent GC who met the eligible criteria were enrolled. Paclitaxel was administered at a dose of 80 mg/m2 on days 1, 8, and 15, and ramucirumab was administered at a dose of 8 mg/kg on day 1 and day 15 of a 4-week cycle. Primary endpoint was the incidence of adverse events and secondary endpoints were response rate, progression-free survival, and overall survival. A total of 25 patients were enrolled in the full-set analysis. RESULTS: Grade 3 or more adverse events were observed in 21 patients (84.0%). Neutropenia was most frequently observed (68.0%), followed by peripheral sensory neuropathy (12.0%), and febrile neutropenia (12.0%). Median progression-free survival and overall survival were 6.9 months and 13.4 months, respectively. Disease control rate was 88.0%, and response rate of patients with measurable lesions was 52.9%. Notably, no treatment-related deaths occurred. CONCLUSION: Ramucirumab plus paclitaxel as a second-line chemotherapy demonstrated acceptable oncological outcomes, despite the occurrence of frequent adverse events. It is necessary to carefully select patients and adjust treatment regimens in older patients with GC to safely administer chemotherapy and subsequently achieve satisfactory long-term outcomes.

Endoscopic Resection with One-Port Placement: A Newly Developed Technique for the Safe Management of Advanced Endoscopic Resection for Gastric Gastrointestinal Stromal Tumors.

INTRODUCTION: Endoscopic full-thickness resection (EFTR) without laparoscopic assistance (pure EFTR) is an emerging, less invasive treatment for gastrointestinal stromal tumors (GISTs). However, the technique has seldom been performed outside China because of concerns regarding pneumoperitoneum, maintenance of endoscopic view, and endoscopic suturing. This study aimed to evaluate the efficacy and safety of endoscopic resection with one-port placement (EROPP) for gastric GISTs. METHODS: This retrospective study included 17 patients with gastric GISTs originating from the muscularis propria who underwent EROPP between 2019 and 2022. One camera port was inserted in the umbilicus before initiating the endoscopic procedure to maintain intra-abdominal pressure, which was monitored and adjusted via this port. While allowing for conversion to laparoscopic surgery if needed, EFTR was performed as follows: (1) circumferential incision of the mucosal and submucosal layers around the lesion was performed by typical endoscopic submucosal dissection; (2) an intentional perforation and subsequent seromuscular resection was made using dental floss and an endo-clip for traction; and (3) closure of the gastric full-thickness defect was performed with an over-the-scope clip (OTSC) after peroral retrieval of the specimen. We retrospectively assessed the short-term outcomes and safety. RESULTS: All procedures were completed successfully without conversion to laparoscopic surgery. The median size of the resected tumors was 23 mm (range, 8-35 mm), the median resection time was 36 min (range, 22-95 min), and closure time was 18 min (range, 10-45 min). The rates of en bloc and complete resection were 100% and 88%, respectively. In 2 cases, another port was added to aspirate the leaking fluid or check the condition of the endoscopic closure. All gastric defects were endoscopically closed, mainly using OTSCs. The recovery course for all patients was uneventful, and no adverse events were reported. CONCLUSIONS: EROPP is a safe and minimally invasive treatment for gastric GISTs and appears to be suitable for introducing EFTR procedures.

Long-term Outcomes of Neoadjuvant Chemotherapy With Docetaxel, Cisplatin and S-1 for Stage III Gastric Cancer.

BACKGROUND/AIM: In the previous phase I/II study, we established neoadjuvant chemotherapy (NAC) using bi-weekly docetaxel, cisplatin, and S-1 (DCS) for clinical stage III gastric cancer. This study aimed to clarify long-term outcomes of this treatment. PATIENTS AND METHODS: Relapse-free survival (RFS) and overall survival (OS) were calculated by the Kaplan-Meier method and prognostic factors for RFS and OS were identified by univariate analysis. RESULTS: A total of 47 patients with clinical stage III gastric cancer were enrolled in this study. The 5-year RFS and OS rates were 69.8% and 74.3%, respectively, in all registered patients. Moreover, the 5-year OS and RFS rates in patients receiving R0 gastrectomy were 68.0% and 79.4%, respectively. Neutrophil-lymphocyte ratio (NLR) before NAC ≥2.41, prognostic nutritional index (PNI) before NAC ≤50.4, Glasgow prognostic score before NAC classification 2, NLR after NAC ≥1.43, PNI after NAC <48.0, and Grade 1a/1b pathological response significantly worsened RFS. NLR after NAC ≥1.43, PNI before NAC ≤50.4, NLR after NAC ≥1.43, and body weight loss >5 kg after NAC significantly worsened OS. CONCLUSION: Although bi-weekly DCS therapy as neoadjuvant setting showed acceptable long-term outcomes, poor immune-nutritional status before and after NAC caused worse long-term survival in stage III gastric cancer patients. It is warranted to conduct a well-designed prospective randomized control study to compare long-term outcomes using the bi-weekly DCS regimen between patients with and without immune-nutritional support during peri-NAC.

Advanced translational PBPK model for transferrin receptor-mediated drug delivery to the brain.

Transferrin receptor (TfR)-mediated transcytosis is an attractive pathway for delivering large-molecule therapeutics to the central nervous system across the blood-brain barrier. Despite the clinical success of some drugs conjugated with TfR-binder, the desired drug profile for efficient TfR-mediated delivery to the targeted compartment within the brain, especially considering the species-related differences, has not been fully elucidated. To provide a prospective direction in the TfR-mediated drug delivery system, we developed an advanced physiologically based pharmacokinetic (PBPK) model. The model addresses TfR-mediated trans- and intracellular disposition of anti-TfR antibodies from brain capillary blood, endothelial cells, extracellular fluid (ECF), and eventually to brain parenchymal cells (BPCs), which correspond to pharmacological target sites of interest. The PBPK model is applicable in rats, monkeys, and human TfR knock-in (hTfR-KI) mice with satisfactory prediction accuracy through model calibration using the brain and plasma PK data of anti-TfR monoclonal antibodies, including their fused protein, with diverse binding affinity to TfR (TfR-Kd). The sensitivity analysis to determine drug properties required for the optimal brain delivery revealed 1) a bell-shaped relationship between TfR-Kd and brain exposure; 2) a minimum species difference between monkeys and hTfR-KI mice in the optimal TfR-Kd range, but not with rats; 3) a low TfR-Kd range to be preferably targeted for BPCs compared with ECF; and 4) an increase in brain exposure when using the pH-sensitive antibody. This may advance model-informed drug development, improve molecular design optimization, and provide precise human dose projection of drugs leveraging TfR-mediated shuttle technology into the brain.