Production and nonclinical evaluation of an autologous iPSC-derived platelet product for the iPLAT1 clinical trial

血小板減少症に対するiPS細胞由来血小板の自己輸血に関する臨床研究」の成果公表（論文発表）について. 京都大学プレスリリース. 2022-09-30.Donor-derived platelets are used to treat or prevent hemorrhage in patients with thrombocytopenia. However, ∼5% or more of these patients are complicated with alloimmune platelet transfusion refractoriness (allo-PTR) due to alloantibodies against HLA-I or human platelet antigens (HPA). In these cases, platelets from compatible donors are necessary, but it is difficult to find such donors for patients with rare HLA-I or HPA. To produce platelet products for patients with aplastic anemia with allo-PTR due to rare HPA-1 mismatch in Japan, we developed an ex vivo good manufacturing process (GMP)–based production system for an induced pluripotent stem cell–derived platelet product (iPSC-PLTs). Immortalized megakaryocyte progenitor cell lines (imMKCLs) were established from patient iPSCs, and a competent imMKCL clone was selected for the master cell bank (MCB) and confirmed for safety, including negativity of pathogens. From this MCB, iPSC-PLTs were produced using turbulent flow bioreactors and new drugs. In extensive nonclinical studies, iPSC-PLTs were confirmed for quality, safety, and efficacy, including hemostasis in a rabbit model. This report presents a complete system for the GMP-based production of iPSC-PLTs and the required nonclinical studies and thus supports the iPLAT1 study, the first-in-human clinical trial of iPSC-PLTs in a patient with allo-PTR and no compatible donor using the autologous product. It also serves as a comprehensive reference for the development of widely applicable allogeneic iPSC-PLTs and other cell products that use iPSC-derived progenitor cells as MCB

Programmed cell death 1 as prognostic marker and therapeutic target in upper gastrointestinal cancers

Gastrointestinal (GIs) cancers are among the most common causes of cancer related death, and hence the importance for the identification of novel prognostic/predictive biomarkers for detection of patients at an early stage, and for using these to identify novel targeted therapies to improve the efficacy of existing chemotherapeutic regimens. Programmed cell death 1 has been reported as a potential target in several malignancies, and targeting agents are being developed, some already approved by FDA, such as: pembrolizumab, Atezolizumab, Nivolumab. Pembrolizumab that have been approved for the treatment of metastatic non-small cell lung cancer. Here we provide an overview of the mechanism of action PD-1/PD-L1, prognostic value and current progress in clinical trials using PD-1/PD-L1 inhibitors, and the resistant mechanisms at underlie the inhibitory effect of these agents in the treatment of gastrointestinal cancers

Case Report Total Hip Arthroplasty for Rapidly Destructive Coxarthrosis in a Patient with Severe Platelet Deficiency due to Liver Cirrhosis and Immune Thrombocytopenic Purpura

Rapidly destructive coxarthrosis (RDC) causes rapid and extreme destruction of the hip joint, which was reported by Postel and Kerboull. RDC is commonly unilateral and occurs mostly in elderly women. Immune thrombocytopenic purpura (ITP) is characterized by a low platelet count that is the result of both immune-mediated platelet destruction and suppression of platelet production. In patients with ITP undergoing surgery, bleeding associated with a low preoperative platelet count can lead to unsuccessful outcomes. To the best of our knowledge, there has been only one report describing total hip arthroplasty (THA) for patients with ITP and there have been no reports of THA for RDC with a very low platelet count due to liver cirrhosis (LC) and ITP. We report the case of a patient who had right RDC and a very low platelet count due to LC and ITP in whom THA was successfully performed. Furthermore, this case was also unique in that her platelet count increased after THA. THA for right RDC might resolve ITP by relieving inflammation of the right hip since her platelet count recovered after THA

Dasatinib and Prednisolone Induction Therapy for a Case of Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia with Dilated Cardiomyopathy Accompanied by Life-Threatening Ventricular Tachycardia

A 56-year-old man being treated for dilated cardiomyopathy presented with epigastralgia. He was diagnosed with ventricular tachycardia and Philadelphia chromosome-positive acute lymphoblastic leukemia. After treating incessant ventricular tachycardia, we commenced induction therapy for leukemia with dasatinib and prednisolone to minimize toxicity towards cardiomyocytes and the cardiac conduction system. Although dasatinib was temporarily withheld because of a recurrence of ventricular tachycardia, we rechallenged dasatinib while using bisoprolol and amiodarone and achieved a complete hematological response three weeks later. Although drug interactions between dasatinib and amiodarone were of concern, the blood concentration of each drug remained within the safe range after concomitant use, and there were no adverse cardiac effects such as QT prolongation after rechallenging dasatinib. Induction therapy with dasatinib and prednisolone may be an acceptable therapeutic option for Philadelphia chromosome-positive acute lymphoblastic leukemia with severe cardiac complications

Substrate-guided optimization of the syringolins yields potent proteasome inhibitors with activity against leukemia cell lines

Natural products that inhibit the proteasome have been fruitful starting points for the development of drug candidates. Those of the syringolin family have been underexploited in this context. Using the published model for substrate mimicry by the syringolins and knowledge about the substrate preferences of the proteolytic subunits of the human proteasome, we have designed, synthesized, and evaluated syringolin analogs. As some of our analogs inhibit the activity of the proteasome with second-order rate constants 5-fold greater than that of the methyl ester of syringolin B, we conclude that the substrate mimicry model for the syringolins is valid. The improvements in in vitro potency and the activities of particular analogs against leukemia cell lines are strong bases for further development of the syringolins as anti-cancer drugs.National Institutes of Health (U.S.) (Grant AI-16892