Effects of glucokinase activator, DS-7309, on embryo-fetal developmental toxicity in rats and rabbits.

The toxicological effects of DS-7309, a glucokinase activator, on pregnancy and embryo-fetal development in rats and rabbits and maternal blood glucose levels were examined. DS-7309 was administered at 3, 10, or 100 mg/kg to rats from Days 7-17 of pregnancy or at 10, 30, or 100 mg/kg to rabbits from Days 6-18 of pregnancy. In rats, maternal hypoglycemia (approximately 50 mg/dL) was seen at 3 and 10 mg/kg, but it recovered 7 h after dosing, leading to no toxic changes. In contrast, continuous severe maternal hypoglycemia (approximately 40 mg/dL, ≥7 h), fetal eye anomalies, and decreased fetal body weight were noted at 100 mg/kg. In rabbits, no fetal anomalies were seen at 10 and 30 mg/kg where maternal blood glucose level dropped to approximately 60-90 mg/dL, but recovered by 7 h after dosing at the latest. In contrast, at 100 mg/kg, severe hypoglycemia (around 60 mg/dL) was maintained and did not recover until 24 h after dosing; it resulted in decreased fetal viability and increased fetal skeleton anomalies. These findings indicate that DS-7309 could lead to embryo-fetal toxicity in rats and rabbits, with such toxicity considered to be related to continuous severe maternal hypoglycemia.

[Richter syndrome successfully treated with ibrutinib monotherapy: two case reports].

The Richter syndrome (RS) is defined as a histologically diagnosed diffuse large B-cell lymphoma (DLBCL) or Hodgkin lymphoma (HL) in patients with chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma. A standard treatment for RS has not yet been established. Most patients with RS are treated with combination chemotherapy regimens used for de novo DLBCL or HL. Recently, the Bruton's tyrosine kinase inhibitor, ibrutinib (IBR), has shown remarkable efficacy in CLL; however, limited evidence exists regarding its single agent efficacy in RS. We encountered two patients with RS in whom CLL transformed to DLBCL, confirmed by G-banding/spectral karyotyping analysis. Both patients achieved durable responses for 12 and 10 months, with IBR alone. Hemorrhagic cystitis due to adenovirus occurred in one patient at an initial dose of 420 mg/day, but a dose reduction to 280 mg/day made long-term continuation of IBR possible. Interestingly, retreatment with IBR alone achieved disease control again for 5.5 and 2 months, after these patients underwent salvage chemotherapies for aggressive relapse.