Update and Current Challenges for Biosimilars in Japan

Despite its benefits, biosimilars are currently underutilized in Japan, where a lack of information and educational activities have created an environment non-conducive for full adoption. A new article published in Future Medicine, focuses on the current climate of biosimilars in Japan, using the biosimilar trastuzumab (proven effective in the treatment of breast cancer) as an example.

Breast cancer is currently the leading specific cancer affecting Japanese women, with 76,257 female breast cancer patients listed as of 2014, and 14,285 mortalities occurring as of 2017. Although most breast cancers are operable with no distant spreading detected at diagnosis, recurrent breast cancer, which is experienced in 20-30% of patients, is challenging to cure, with such patients requiring drug therapy intervention to prolong their lives. Physicians recommend drug therapy for breast cancer based on the cancer’s subtype, determined by the expression of hormone receptors and the human epidermal growth factor receptor 2 (HER2). An overexpression of HER2 can result in a malfunction of gene signaling that leads to uncontrollable cancer growth.

The use of anti-body targeting biologics that pinpoint HER2-positive breast cancer has significantly improved breast cancer prognosis. Trastuzumab represents the first human antibody specifically designed to target the HER2 protein, and combats breast cancer by impeding growth factor signaling. A previous cohort study conducted in Japan revealed that trastuzumab therapy positively affects outcomes in patients diagnosed with early stage breast cancer. A third phased trial (the CLEOPATRA study) showed that the use of trastuzumab in conjunction with pertuzumbab and docetaxel (two antibodies that also combat HER2) precipitably extended the survival rate of breast cancer patients included in the study, and is now considered the standard, first-line treatment for HER2-positive metastatic breast cancer.

While anti-HER2 antibodies are shown to prolong life, the high price of biologics is problematic, prompting the American Society of Clinical Oncology to issue a statement that stresses the importance of developing and evaluating cost-effective biologics. Therefore, the need for producing biosimilars that provide a lower cost without scarifying safety or efficacy has increased, prompting the approval of three trastuzumbab biosimilars (CT-P6, ABP980, and PF-05280014) in Japan.

However, a recent survey displayed biosimilars have yet to be fully recognized and understood by physicians, pharmacists, as well as patients in Japan, with 43% of Japanese oncologists conveying unfamiliarity with the products. Some physicians cite a concern in the use of biosimilars by what they perceive as insufficient clinical data.

Recently, the Japanese government began promoting the use of biosimilars, backing supportive measures for their development. The Japanese government also plans ramp up educational activities to bolster the population’s understanding of biosimilars. The American Society of Clinical Oncology issued position statements and guidance for oncologists aiming to guide sound decision-making concerning biosimilar treatment in oncology. Other materials are now readily available to promote biosimilar understanding while encouraging communication about the products with inquiring patients.

Regarding the future, the authors of this review wrote noted that “since maintaining the current Japanese healthcare system is essential to realize the clinical benefits of these new therapies, [reducing] healthcare cost, including drug costs, will be more and more important.” Because various breakthrough therapies, such as antibody drug conjugates and immune checkpoint inhibitors, may be approved and implemented to impact cancer treatment in Japan, trastuzumab biosimilars are poised to play a leading