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Antibody-drug conjugates (ADCs) combine the specific antibody and cytotoxic agent by a linker and represent a promising drug class with a wider therapeutic window than conventional chemotherapeutic agents by substantiating efficient and specific drug delivery to antigen-expressing tumor cells. However, there are rooms for improvement in terms of efficacy, safety, physicochemical property; therefore, the development of promising ADC drugs across multiple indications are eagerly awaited. In 2015, Daiichi Sankyo initiated the first-in-human study of HER2 ADC, trastuzumab deruxtecan (T-DXd, ENHERTU®) which possesses DNA topoisomerase I inhibitor, exatecan derivative and proprietary linker, in Japan. Based on the provocative results in phase 1 study, the global development program has been accelerated to show the high and durable efficacy in patients with HER2 positive breast cancer pretreated with trastuzumab emtansine. As a result, T-DXd was approved based on single arm phase 2 study in the US (Dec 2019) and Japan (March 2020) by leveraging the breakthrough designation and conditional early approval system, respectively, at the first time for the HER2 positive breast cancer. In addition, T-DXd was recently approved in gastric cancer through Sakigake designation in Japan based on a randomized phase 2 study. T-DXd is also being developed in the earlier lines or other indications where no anti-HER2 therapies were approved to date. Combination studies with other agents, such as immune checkpoint inhibitors are underway. In the near future, we hope that more patients worldwide can enjoy the therapeutic benefits of T-DXd through our continuous efforts to expand its indications.

Antibody-drug conjugates (ADCs) combine the specific antibody and cytotoxic agent by a linker and represent a promising drug class with a wider therapeutic window than conventional chemotherapeutic agents by substantiating efficient and specific drug delivery to antigen-expressing tumor cells. However, there are rooms for improvement in terms of efficacy, safety, physicochemical property; therefore, the development of promising ADC drugs across multiple indications are eagerly awaited. In 2015, Daiichi Sankyo initiated the first-in-human study of HER2 ADC, trastuzumab deruxtecan (T-DXd, ENHERTU

Primary hepatic neuroendocrine carcinoma is rare and its origin is not clearly understood. An admixture of hepatocellular carcinoma (HCC) and neuroendocrine carcinoma is particularly rare. Here, we report a patient with an extremely rare combination of HCC and neuroendocrine carcinoma of the liver. To our knowledge, this is the first reported case in which the carcinoma showed sarcomatous change. The patient was a 76-year-old man who had received outpatient treatment for chronic hepatitis C. On abdominal computed tomography (CT), the hepatic tumor was enhanced in the arterial phase but its density was lower than that of normal liver in the portal phases. His serum α-fetoprotein (AFP) level was very high. Therefore, transarterial chemoembolization (TACE) was performed based on the diagnosis of HCC. Ten months after TACE, his serum AFP level had increased to the level measured before TACE. Partial hepatectomy was performed because CT revealed poor enhancement of the recurrent tumor. Histopathologically, the tumor consisted of two distinct components: moderately differentiated HCC was intermingled with a neuroendocrine carcinoma, which was accompanied by sarcomatous changes. Immunohistochemically, the neuroendocrine carcinoma cells were positive for CD56, chromogranin A and neuron-specific enolase, and negative for AFP. The sarcomatous area was positive for AE1/3 and CD56, consistent with sarcomatous change of neuroendocrine carcinoma. The neuroendocrine carcinoma and/or sarcomatous change may have been due to phenotypic changes and/or dedifferentiation of HCC induced by TACE. Six months after surgery, the patient was diagnosed with metastasis of the neuroendocrine carcinoma to sacral bone. He died 7 months after surgery.

Primary hepatic neuroendocrine carcinoma is rare and its origin is not clearly understood. An admixture of hepatocellular carcinoma (HCC) and neuroendocrine carcinoma is particularly rare. Here, we report a patient with an extremely rare combination of HCC and neuroendocrine carcinoma of the liver. To our knowledge, this is the first reported case in which the carcinoma showed sarcomatous change. The patient was a 76-year-old man who had received outpatient treatment for chronic hepatitis C. On abdominal computed tomography (CT), the hepatic tumor was enhanced in the arterial phase but its density was lower than that of normal liver in the portal phases. His serum α-fetoprotein (AFP) level was very high. Therefore, transarterial chemoembolization (TACE) was performed based on the diagnosis of HCC. Ten months after TACE, his serum AFP level had increased to the level measured before TACE. Partial hepatectomy was performed because CT revealed poor enhancement of the recurrent tumor. Histopathologically, the tumor consisted of two distinct components: moderately differentiated HCC was intermingled with a neuroendocrine carcinoma, which was accompanied by sarcomatous changes. Immunohistochemically, the neuroendocrine carcinoma cells were positive for CD56, chromogranin A and neuron-specific enolase, and negative for AFP. The sarcomatous area was positive for AE1/3 and CD56, consistent with sarcomatous change of neuroendocrine carcinoma. The neuroendocrine carcinoma and/or sarcomatous change may have been due to phenotypic changes and/or dedifferentiation of HCC induced by TACE. Six months after surgery, the patient was diagnosed with metastasis of the neuroendocrine carcinoma to sacral bone. He died 7 months after surgery.

The desired 5,6-dihydro-4H-pyrrolo[3,4-d]thiazole (VII) is readily prepared via a Mitsunobu reaction of diol (IV) with sulfonamide (V).

We investigated the effect and safety of chemotherapy for patients over eighty-year-old.Ten patients with advanced or recurrent pancreas or biliary tract cancer who were over 80 years old and administered gemcitabine hydrochloride (GEM), were named as "the oldest group", and compared with the control group.The overall response rate was 22. 2% without a significant difference between those 2 groups. The mean duration of treatment and the mean period from the initial chemotherapy to death were 8. 0 and 12 months, respectively, without a significant difference. There was a higher incidence of initial reduction of GEM in the oldest group. There was no significant difference at the DI ratio (actual drug intensity/ideal drug intensity) between 2 groups. Side effects found were 5 cases of neutropenia, 4 cases of anemia and appetite loss greater than grade 3. The dropout ratio (50%) in the oldest group was significantly higher. There was no death related with chemotherapy.Chemotherapy can be used safely and usefully, if appropriately reduced from first administration, for a patient over eighty years old.

In the early 1990's, we reported on the low-molecular selective fXa inhibitor DX-9065a having two amidino groups. However, it had poor oral bioavailability due to its strong basic amidino groups. To obtain fXa inhibitors with improved oral bioavailability, we investigated various non-amidino fXa inhibitors and finally discovered cis-1,2-diaminocyclohexane derivative 4c to have potent fXa inhibition, promising anticoagulant activity, and good oral bioavailability, compared with amidino compound DX-9065a. In addition, we will discuss the influence of the third substituent on the cyclohexane ring on anti-fXa activity, anticoagulant activity, PK profile, and lipophilicity.

The improved routes to prepare tetrahydrothiazolo[5,4-c]-pyridine-2-carboxylic acid lithium salts (2 and 3) were developed. Route A is consisted of the improved preparation of thiazolopyridine intermediates, and Route B is applicable for a large scale synthesis of tetrahydrothiazolo[5,4-c]pyridine-2-carboxylic acid derivatives. The methods we developed may serve as facile means for preparing thiazolopyridine and tetrahydrothiazolopyridine derivatives.