This is the 5985th most frequent Japanese word.
アステラス
"アステラス" (Asteras) is the name of a Japanese pharmaceutical company, Astellas Pharma.
In this sentence, "アステラス" refers to the company name "Astellas Pharma." It's a proper noun.
アステラス製薬は有名な製薬会社です。
Astellas Pharma is a famous pharmaceutical company.
Here, "アステラス" signifies the company where the researchers are employed.
アステラスの研究者たちは新しい薬を開発しています。
Researchers at Astellas are developing new medicines.
In this context, "アステラス" points to the corporate entity and its culture.