On 16 September 2026, MSD’s subcutaneous pembrolizumab was approved in Japan under the name Keyject™. Keyject™ (pembrolizumab and berahyaluronidase alfa) is approved for the same indications as Keytruda® (IV formulation) and is the first subcutaneous immune checkpoint inhibitor approved in Japan.
MSD’s subcutaneous pembrolizumab has been approved in a number of countries, including in the US as Keytruda Qlex™ (September 2025), and in the EU (November 2025), Canada (February 2026), Korea (May 2026) and Australia (July 2026), as Keytruda SC™.
MSD is currently engaged in disputes with Halozyme in relation to Keytruda SC™, with Halozyme alleging that MSD is infringing various patents to Halozyme’s MDASE™ subcutaneous delivery technology, including:
- in April 2024, Halozyme sued MSD in the US, alleging that MSD’s subcutaneous Keytruda® (Keytruda Qlex®) infringes 15 patents. MSD has successfully invalidated claims of a number of Halozyme’s US patents before the Patent Trial and Appeal Board;
- in December 2025, the Munich Regional Court granted a preliminary injunction (PI) to Halozyme, preventing MSD from distributing and offering for sale in Germany Keytruda SC™; and
- in July 2026, the District Court of The Hague published a judgment dismissing Halozyme’s application for a PI to prevent MSD from marketing Keytruda SC™ (pembrolizumab and berahyaluronidase alfa) in Denmark and Sweden pending the outcome of substantive proceedings.
While there are no reports of biosimilar subcutaneous pembrolizumab development to date, there are multiple pembrolizumab biosimilars approved or in development. Samsung Bioepis and Celltrion each applied for Korean approval of their pembrolizumab biosimilars in August 2026 (SB27 and CT-P51, respectively). In June 2026, Samsung Bioepis claimed to be the first developer of a pembrolizumab biosimilar to announce global phase 3 trial results. Amgen also confirmed on 15 September 2026 that its Keytruda® biosimilar has successfully completed clinical trials with an FDA submission likely later this year. Formycon announced successful Phase 1 results in February 2026, with its US commercialisation partner, Zydus, expressing optimism that it is well-placed to file the first BLA in the US for biosimilar pembrolizumab.
Pembrolizumab biosimilars have reportedly been launched in Paraguay (by Bioeticos in August 2025) and approved in Vietnam (by Biocad in November 2025) and Jordan (by Sana Pharma in February 2026). Pembrolizumab biosimilars are also in clinical trials including by mAbxience, Sandoz, Bio-Thera, Shanghai Henlius, BioNTech, Qilu Pharmaceutical and Enzene.