Approved in China as the first subcutaneous PD-1 inhibitor, securing 19 solid tumor indications
Asian commercial rollout accelerates across South Korea, Japan, and China as market monitors IV-to-SC transition speed
Keytruda SC, incorporating South Korean biotech Alteogen Inc.’s (196170) subcutaneous (SC) formulation technology, has officially entered the Chinese market. Following the start of commercial supply in South Korea on October 1 and regulatory approval in Japan last month, the addition of China—home to a massive cancer patient population—significantly broadens the drug's commercial reach across Asia.
Global pharmaceutical giant Merck (known as MSD outside the U.S. and Canada) announced on September 29 that the subcutaneous formulation of its PD-1 inhibitor pembrolizumab received regulatory approval from China’s National Medical Products Administration (NMPA).
The clearance covers 19 solid tumor indications. Keytruda SC is the first and currently only subcutaneous PD-1 inhibitor approved in China.
Keytruda SC utilizes ALT-B4 (berahyaluronidase alfa), a proprietary human hyaluronidase variant developed by Alteogen. The technology enables the subcutaneous administration of Keytruda, which was previously delivered exclusively via intravenous (IV) infusion.
Expanding Global Rollout: From North America to East Asia
The global regulatory momentum for Keytruda SC began in the United States in September last year, followed by approval in the European Union in November and Canada earlier this year.
More recently, commercial approvals and launches have gathered speed across major Asian markets. In South Korea, following approval by the Ministry of Food and Drug Safety in May, commercial supply began on October 1. Japan also granted manufacturing and marketing authorization last month under the local product name "KEYJECT," covering all indications previously approved for IV Keytruda in the country.
With China now included, Keytruda SC has built a robust commercial foundation across North America, Europe, and key Asian markets.
The rapid pace of global expansion is notable: in roughly one year since its initial U.S. clearance, the subcutaneous formulation has secured successive regulatory approvals across major economies, expanding the geographic markets where commercial sales can take place.
19 Indications at Once: Unlocking China’s Massive Market
The approval in China represents a major commercial milestone given the sheer size of the market. According to the International Agency for Research on Cancer (IARC), an agency under the World Health Organization (WHO), China recorded approximately 4.82 million new cancer cases in 2022—accounting for a substantial share of the 20 million new cases reported globally that year.
Crucially, the regulatory approval encompasses 19 solid tumor indications simultaneously. Because MSD already markets IV Keytruda across multiple cancer types in China, the SC formulation can enter the market built on Keytruda’s established clinical footprint.
China’s immuno-oncology landscape is highly competitive, with numerous local and international PD-1 therapies vying for market share. However, Keytruda SC holds a distinct advantage as the first and only subcutaneous option available. Industry observers are closely watching how its ability to drastically reduce administration time compared to conventional IV infusions will differentiate it in the Chinese market.
Given China’s vast patient base, the speed of patient conversion from IV to SC will be a critical metric. Unlike therapies entering entirely new indication areas, Keytruda SC can leverage existing clinical infrastructure and customer bases. The rate at which current IV demand shifts to SC post-launch will serve as a primary indicator of its commercial adoption speed.
From Approval to Sales: Market Attention Shifts to Conversion Speed
For Alteogen, regulatory approval in China significantly broadens the commercial addressable market for Keytruda SC.
Alteogen’s licensing agreement with MSD includes up to $1 billion in total sales milestone payments tied to Keytruda SC’s commercial performance. Alteogen has already received its first sales milestone payment of $25 million.
With commercial supply underway in South Korea and regulatory approvals finalized in Japan and China, the foundation is laid for sales momentum in North America to extend into other major global markets.
Going forward, the focus will be on the specific launch timelines in each country and the speed at which healthcare providers convert IV Keytruda prescriptions to the SC formulation. In particular, the conversion velocity in China across all 19 indications will directly impact the timing of Alteogen’s future sales milestone payments.
