Celltrion biosimilars gain dominance in Japanese drug market

Celltrion’s oncology biosimilars are rapidly solidifying their market dominance in Japan, one of Asia’s largest pharmaceutical markets, with two leading products -- breast and gastric cancer treatment Herzuma (ingredient: trastuzumab) and metastatic colorectal and breast cancer Vegzelma (ingredient: bevacizumab).

According to data from IQVIA, Herzuma, a biosimilar referencing Roche’s Herceptin, held a commanding 75 percent market share as of April 2025, maintaining its top position among five trastuzumab-based therapies available in Japan. 

The product surpassed Herceptin in the second quarter of 2021 and has since remained the most prescribed trastuzumab product for four consecutive years.

Vegzelma, a biosimilar referencing Avastin, has also quickly gained traction after entering the Japanese market in January 2023 as the latest bevacizumab biosimilar.

Despite being the sixth and final entrant among bevacizumab products in Japan, Vegzelma achieved a 29 percent market share as of April. It now trails the top-prescribed product by just two percentage points, signaling a strong possibility of overtaking the market lead in the near future.

The company attributed the success of Celltrion’s oncology products in Japan to a combination of strategic local marketing and regulatory advantages. 

The company’s Japanese affiliate and distribution partners have leveraged a tailored commercial strategy that aligns with the unique characteristics of the Japanese pharmaceutical system.

Notably, Celltrion capitalized on Japan’s Diagnosis Procedure Combination (DPC) reimbursement system, a government policy widely considered favorable to biosimilars. 

Under the DPC scheme, hospitals are incentivized to prescribe cost-effective drugs because they retain savings generated by using lower-priced medicines. This structure benefits hospitals, patients, and the government alike.

Celltrion’s dominance in Japan extends beyond oncology. Its flagship autoimmune disease biosimilar, Remsima (ingredient: infliximab), leads the Japanese biosimilar market with a 41 percent share as of April 2025, while Yuflyma (ingredient: adalimumab), launched earlier this year, has rapidly grown from 8 percent to 12 percent market share in just four months.

“The outstanding prescription results of all four Celltrion biosimilars in Japan demonstrate the effectiveness of our hands-on, field-based sales strategy tailored for Japan’s retail-oriented drug supply model,” a Celltrion official said. “With the planned launch of our ustekinumab biosimilar, Stekima, later this year, we will build on our local experience and market insights to ensure swift market penetration and continued success.”