On November 23, the application for the Bayer prostate cancer new drug Xofigo (Rainium Chloride [223Ra] Injection) was officially accepted by CDE.
Xofigo was first approved by the FDA on May 15, 2013 for the treatment of advanced bone metastases in castration-resistant prostate cancer. In the Phase 3 ALSYMPCA study, Xofigo combined with Best Supportive Care (BSoC) compared with placebo in the BSoC group extended overall survival by 3.6 months (14.9 vs 11.3 months) and reduced the risk of death by 30%. In addition, the time to first symptomatic skeletal events in patients treated with Xofigo was postponed (15.6 vs 9.8 months) compared with placebo. In 2017, Xofigo’s global sales reached 408 million euros.
Prostate cancer is an androgen-dependent tumor, and androgen can stimulate the growth and disease progression of prostate cancer cells. Traditional endocrine therapies include castration therapy to block testicular-derived androgens (surgical resection of bilateral orchiectomy, injection of goserelin, etc.) and anti-male therapy (oral anti-androgenic drugs) to block adrenal-derived androgens. However, as the disease progresses, although the androgen from the testis and adrenal glands is blocked, the ability of the tumor cells to biosynthesize androgens is increased, and the mutated androgen receptor (AR) is more sensitive to low levels of androgens. It can still drive disease progression, and the disease state at this time is prostate cancer at the stage of castration resistance.
The survival of patients with prostate cancer is relatively longer than that of other malignant tumors, but it is also prone to distant metastasis during long-term survival. The total incidence of bone metastases in castration-resistant prostate cancer is between 65% and 75%, whereas in metastatic castration-resistant prostate cancer (mCRPC), the incidence of bone metastases is >90%. Patients with bone metastases often have bone-related events and thus increase the risk of death in prostate cancer patients by 28%.
Current drugs for the treatment of bone metastases in prostate cancer include classic bisphosphonates, RANK inhibitors, and radiopharmaceuticals. Previous radionuclide drugs have a large adverse reaction, and radiotherapy is not a routine recommendation for patients with prostate cancer. As the understanding of nuclides has gradually deepened, radiopharmaceuticals have once again entered everyone’s field of vision.
Radiotherapy drugs have become a hot spot in 2018. Following Xofigo, the FDA approved Advanced Accelerator Applications 177Lu-oxodotreotide for the treatment of somatostatin receptor-positive gastrointestinal pancreatic neuroendocrine tumors in January this year, which was acquired by Novartis in early October for $3.9 billion. And Novartis, who entered the field of radiotherapy, then acquired Endocyte for $2.1 billion on October 18 to obtain its first-in-class project for the treatment of metastatic castration against prostate cancer in phase III. 177Lu- PSMA-617, continue to strengthen the radiopharmaceutical pipeline.