On 11 November 2025, Viet Nam News, reported that the Vietnam Ministry of Health has granted marketing authorisation for Pembroria™, biosimilar to MSD’s Keytruda® (pembrolizumab), in Vietnam for a three-year period.

Pembroria™ is reportedly manufactured in Russia by a Russian company, Limited Liability “PK-137”.  However, the product was developed by Biocad, which initiated phase 1 clinical trials for the biosimilar (then known as BCD-201) in 2022.

On 31 October 2025, Biocad announced that BCD-201 demonstrated a favourable safety and efficacy profile in real-world clinical trials in Cuba in patients with metastatic and inoperable melanoma.  Biocad claims to have been supplying anticancer drugs such as pembrolizumab to Cuba free of charge since 2023.

Bioéticos claimed to have launched the first pembrolizumab biosimilar in Paraguay in August 2025 under the name Pembrolizumab Bioéticos.  A number of other pembrolizumab biosimilars are currently in clinical trials, including by Samsung Bioepis, Amgen, mAbxience, Sandoz, Formycon, Celltrion, Bio-Thera and BioNTech.  Alvotech and Dr Reddy’s have entered into a global collaboration and licence agreement to co-develop, manufacture and commercialise a biosimilar to Keytruda®.

Between 18 and 23 September 2025, the US Patent Trial and Appeal Board (PTAB) issued final decisions invalidating Johns Hopkins University’s 11,339,219 (IPR2024-00625), 11,649,287 (IPR2024-00647), 11,629,187 (IPR2024-00649) and 11,634,491 (IPR2024-00650) in four inter partes review proceedings (IPRs) brought by MSD.  JHU subsequently filed an appeal in relation to Patent 11,649,287 (IPR2024-00647) on 7 October 2025.

The four JHU patents relate to the use of pembrolizumab in treating cancer patients with high mutational burdens, such as those found in microsatellite instability high (MSI) or DNA mismatch repair deficient cancer (dMMR).  The PTAB found that the patents were invalid for lack of novelty and/or obviousness based on prior art including a record of a JHU phase 2 clinical trial of Keytruda® (pembrolizumab) in MSI/dMMR cancer.

The four IPRs are a subset of nine IPRs filed by MSD against JHU patents in 2023 – 2024.  One of the IPRs had previously been determined in June 2025, finding US 11,591, 393 invalid.  The remaining four IPRs remain pending:

• 10,934,356 (IPR2024-00622), 11,325,974 (IPR2024-00623), 11,325,975 (IPR2024-00624): filed on 4 March 2024 and instituted on 23 September 2024; and
• 11,643,462 (IPR2024-00648): petition filed 13 March 2024, IPR instituted 3 October 2024.

In November 2022, MSD filed a complaint in the United States District Court (District of Maryland) against JHU seeking declarations of breach of contract, non-infringement and promissory estoppel.  Based on the complaint, the dispute arose out of a contract between MSD and JHU to design and conduct a clinical trial on administration regimes for Keytruda® (pembrolizumab) in cancer patients with certain genetic biomarkers.  JHU filed a counter-claim on 12 April 2023, including alleging infringement of each of the patents subject to the IPR proceedings referred to above.  The US Court proceeding has been stayed pending the outcome of the IPRs.  No trial date has been scheduled.

On 26 September 2025, Shanghai Henlius announced that the first patient has been dosed in its phase 1 multicentre clinical trial for HLX17, biosimilar to MSD’s Keytruda® (pembrolizumab).

The trial is being conducted in China to evaluate the pharmacokinetic profile, efficacy, safety and immmunogencity of HLX17 in comparison to US-sourced Keytruda® in patients with multiple-resected solid tumours (including non-small cell lung cancer, melanoma, or renal cell carcinoma).

A number of pembrolizumab biosimilars are currently in clinical trials, including by Samsung Bioepis, Amgen, mAbxience, Sandoz, Formycon, Celltrion, Bio-Thera and BioNTech.  Alvotech and Dr Reddy’s have entered into a global collaboration and licence agreement to co-develop, manufacture and commercialise a biosimilar to Keytruda®.  Bioéticos claims to have launched the first pembrolizumab biosimilar in Paraguay in August 2025 under the name Pembrolizumab Bioéticos.

On 24 September 2025, Medical Dialogues reported that India’s Subject Expert Committee (SEC) of the Central Drugs Standard Control Organisation (CDSCO) has instructed Intas Pharmaceuticals to submit a revised protocol for its proposed biosimilar pembrolizumab Phase I/III clinical trial.

Intas’ proposed clinical trial is intended to be a multicentre study comparing the efficacy, safety, pharmacokinetics and immunogenicity of INTP58 with MSD’s Keytruda® (pembrolizumab), both administered with chemotherapy, in first line treatment of locally advanced or metastatic squamous or non-squamous non-small cell lung cancer.  The SEC raised a number of issues in relation to the trial protocol, including that the study duration should be increased, and the dose of chemotherapy (paclitaxel) should be reduced.

There are a number of pembrolizumab biosimilars already in clinical trials, including those of Samsung Bioepis, Amgen, mAbxience, Sandoz, Formycon, Celltrion, Shanghai Henlius, Bio-Thera and BioNTech.  Alvotech and Dr Reddy’s entered into a global collaboration and licence agreement to co-develop, manufacture and commercialise a biosimilar to Keytruda®.  Bioéticos claimed to have launched the first pembrolizumab biosimilar in Paraguay in August 2025, under the name Pembrolizumab Bioéticos.

On 19 September 2025, MSD announced that Keytruda Qlex™ (pembrolizumab and berahyaluronidase alfa-pmph; MK-3475A) has been approved by the FDA for subcutaneous use in adults across 38 indications, covering most solid tumour indications for Keytruda® (pembrolizumab).  MSD is planning a late September 2025 US launch for Keytruda Qlex™.

According to Business Korea, if Keytruda Qlex™ successfully penetrates the market, Alteogen, the developer of hyaluronidase technology used with the subcutaneous formulation, is expected to generate annual royalty income exceeding 1 trillion won.

The FDA had accepted MSD’s BLA for SC pembrolizumab in March 2025, with a target action date of 23 September 2025.

The good news for MSD comes a day after the European Medicines Agency (EMA) Committee for Medicinal Products for Human Use (CHMP) recommended a change to the marketing authorisation for MSD’s Keytruda®, adopting a new pharmaceutical form, solution for injection, associated with two new strengths (790 mg and 305 mg), together with subcutaneous use as a new route of administration.

MSD was sued by Halozyme in the US on 24 April 2025 in relation to SC pembrolizumab, with Halozyme alleging that it infringes 15 patents owned by Halozyme in relation to MDASE subcutaneous delivery platform.  The lawsuit followed reports in March 2025 that Halozyme had offered MSD an opportunity to licence its MDASE patents.  At the time, a spokesperson from MSD said the enzyme used in SC Keytruda® was “developed independently” from Halozyme and that MSD “strongly believe” that any Halozyme patents that attempt to cover the enzyme variant are invalid.

MSD has filed 14 petitions for post-grant review with the US Patent Trial and Appeal Board challenging the validity of US patents owned by Halozyme, a number of which are asserted in the litigation.  The petitions were filed between November 2024 and June 2025.  Petitions in relation to 5 patents have been instituted (US 11952600 (2 June 2025), US 12018298 (11 June 2025), US 12152262 (16 June 2025), US 12123035 (11 July 2025), US 12110520 (8 September 2025)), while others are pending.

On 5 September 2025, the World Health Organisation (WHO) announced that it has updated its Model List of Essential Medicines (EML) to include pembrolizumab (including “quality assured biosimilars”) as a first-line monotherapy for metastatic cervical cancer, metastatic colorectal cancer, and metastatic non-small cell lung cancer (NSCLC).  Atezolizumab and cemiplimab (including “quality assured biosimilars”) are listed as therapeutic alternatives to pembrolizumab for metastatic NSCLC.

The WHO Model Lists are updated every two years and are intended as a guide for countries or regional authorities to adopt or adapt in accordance with local priorities and treatment guidelines for the development and updating of national essential medicines lists.  Essential medicines are those considered to satisfy the priority health care needs of a population.

Amongst the biopharmaceuticals added to the Model List this year, ustekinumab and adalimumab (with certolizumab pegol, etanercept and infliximab as therapeutic alternatives) were also added to a complementary list (medicines for which specialised monitoring, diagnostics or care are required) for the treatment of adults and children with moderate-to-severe psoriasis.  Emicizumab has been included on the Model List for Haemophilia A.

MSD’s Keytruda® (pembrolizumab) has been approved in multiple jurisdictions for multiple cancer-related indications.  In August 2025, Bioéticos claimed to have launched the first pembrolizumab biosimilar in Paraguay, under the name Pembrolizumab Bioéticos.  A number of pembrolizumab biosimilars are currently in clinical trials, including those of Samsung Bioepis, Amgen, mAbxience, Sandoz, Formycon, Celltrion, Shanghai Henlius, Bio-Thera and BioNTech.  Alvotech and Dr Reddy’s have entered into a global collaboration and licence agreement to co-develop, manufacture and commercialise a biosimilar to Keytruda®.

No biosimilars to Roche’s Tecentriq® (atezolizumab) or Regeneron and Sanofi’s Libtayo® (cemiplimab) have been approved to date.

At its July 2025 meeting, Australia’s Pharmaceutical Benefits and Advisory Committee (PBAC) rejected MSD’s proposal for a multi-indication (broad) listing for Keytruda® (pembrolizumab) in advanced or metastatic cancers.  MSD had proposed that Keytruda® be PBS listed for all usages registered on the Australian Register of Therapeutic Goods (ARTG) for such cancers.

However, the PBAC considered that because the proposed funding model “was restricted to the indications for which pembrolizumab was registered with the Therapeutic Goods Administration” it “would not provide access to some patient groups in which there is a significant unmet clinical need, such as rare cancers.”

MSD said the decision was “bewildering” given “the proposal was developed with the explicit intention of removing immunotherapy access barriers, including for certain rare cancers, where the number of patients involved in a study is often too small to meet requirements for a PBS subsidy”.

In October 2024, PBAC had issued guidance as to the parameters that any broad subsidy proposal for PD-(L)1 inhibitors (such as Keytruda®) would have to address, noting that it was “supportive of implementing simplified listings for PD-(L)1 inhibitors within a specific tumour type if this would facilitate appropriate and timely access for patients”.

At the July 2025 meeting, PBAC also recommended against PBS listing of Keytruda® for the treatment of primary advanced or recurrent endometrial cancer.

Paraguay-headquartered Bioéticos, which is part of Laboratorio Productos Eticos C.E.I.S.A (a member of Savone Holding and part of Insud Pharma) claims to have launched the first pembrolizumab biosimilar in Paraguay, under the name Pembrolizumab Bioéticos.  According to a banner currently appearing on Bioéticos’ website, and a May 2025 LinkedIn post, the biosimilar to MSD’s Keytruda® was developed by mAbxience.

However, in an article dated 14 August 2025, Generics and Biosimilars Initiative noted that as of mid-May 2025, there was no indication that Paraguay’s regulatory authority, DINAVISA (Dirección Nacional de Vigilancia Sanitaria), had officially approved a pembrolizumab biosimilar for use in Paraguay.

There have been no announcements by mAbxience in relation to the product.  Based on the clinicaltrials.gov database, mAbxience is undertaking a Ph 3 study to compare the PK, efficacy, safety and immunogenicity of MB12 (biosimilar pembrolizumab) versus Keytruda® in combination with pemetrexed-platinum chemotherapy as first-line treatment in patients with metastatic nsNSCLC.  The study commenced in December 2024 and is currently recruiting, with estimated primary completion in June 2026.

With a number of biosimilars to MSD’s Keytruda® (pembrolizumab) currently in clinical trials, we provide the following update on those trials and their status, based on previous reports and the information available to date in the clinicaltrials.gov registry:

• Samsung Bioepis (SB27): Ph 3 study to compare efficacy, safety, PK and immunogenicity between SB27 and Keytruda® in patients metastatic nsNSCLC initiated in April 2024. The study is currently recruiting with estimated primary completion in September 2025.
• Amgen (ABP 234): Ph 3 study in nsNSCLC initiated May 2024 to compare PK between ABP 234 and Keytruda® in patients with early-stage nsNSCLC as adjuvant treatment following resection and platinum-based chemotherapy. The study is currently recruiting, with estimated primary completion in March 2026.  Ph 3 study commenced in September 2024 to compare the efficacy, PK, safety and immunogenicity between ABP 234 and Keytruda® in patients with advanced or metastatic nsNSCLC.  The study is currently recruiting, with estimated primary completion in February 2028.
• Formycon (FYB206): Integrated Ph1/3 study commenced in June 2024 to demonstrate PK similarity of FYB206 with Keytruda® in patients with Stage IIB/IIC or Stage III melanoma. On 10 July 2025, Formycon announced that it had completed patient enrolment.  Formycon expects results to be available in Q1 2026.  Formycon had originally intended to conduct a parallel Phase 3 trial to compare the safety and efficacy of FYB206 with Keytruda® in NSCLC.  However, in February 2025, Formycon announced the premature termination of the Phase 3 trial on the basis that the trial was not necessary to obtain US approval of FYB206.
• mAbxience (MB12): Ph 3 study to compare the PK, efficacy, safety and immunogenicity of MB12 versus Keytruda® in combination with pemetrexed-platinum chemotherapy as first-line treatment in patients with metastatic nsNSCLC. The study commenced in December 2024 and is currently recruiting, with estimated primary completion in June 2026.
• Sandoz (GME751): Ph 1 study commenced in May 2024 to compare PK of GME751 and Keytruda® in patients with stage II and III melanoma requiring adjuvant treatment with pembrolizumab. The study is currently recruiting with estimated primary completion in July 2026.  In April 2025, Sandoz announced it has “minimised” its Ph 3 trial in untreated metastatic nsNSCLC due to streamlining of FDA study requirements.
• Celltrion (CT-P51): Ph 3 trial plan approved by FDA in August 2024 with study initiated in January 2025 to compare efficacy and safety of CT-P51 and Keytruda® in combination with platinum pemetrexed chemotherapy in patients with previously untreated metastatic nsNSCLC. The study is currently recruiting with estimated primary completion in February 2027.
• Shanghai Henlius (HLX17): Integrated Ph 1/3 study initiated in April 2025 to evaluate the efficacy, safety, PK profile and immunogenicity of HLX17 vs Keytruda® in the first-line treatment of advanced nsNSCLC. The study is not yet recruiting, with estimated primary completion in April 2027.
• Bio-Thera (BAT3306): Ph 1/3 study commenced in July 2024 to evaluate the PK, efficacy and safety of BAT3306 plus chemotherapy versus Keytruda® plus chemotherapy in patients with stage IV nsNSCLC. The study is currently recruiting with estimated primary completion in July 2027.
• BioNTech (BNT327): Phase 2/3, Master Protocol for a Global Trial of BNT327 in combination with chemotherapy and other investigational agents in first-line NSCLC, initiated in January 2025. The study is currently recruiting, with estimated primary completion in December 2029.

On 10 July 2025, Formycon announced that it has completed patient enrolment for its clinical study, “Dahlia”, which is comparing the pharmacokinetics, safety and tolerability of FYB206 (pembrolizumab) with MSD’s Keytruda® in malignant melanoma.  The study was commenced in June 2024 and has now enrolled a total of 96 participants.

Formycon had originally intended to conduct a parallel Phase 3 trial (“Lotus”) to compare the safety and efficacy of FYB206 with Keytruda® in non-small cell lung cancer (NSCLC).  However, in February 2025, Formycon announced the premature termination of the Phase 3 trial following communications with the US FDA and concluding that the trial was not necessary to obtain US approval of FYB206.

Formycon expects results of the study to be available in Q1 2026, with the earliest market entry of FYB206 being in 2029 for the US and after 2030 for the EU.

There are a number of other pembrolizumab biosimilars in clinical trials, including Celltrion’s CT-P51 (Ph 3 trial plan approved by FDA in August 2024), Bio-Thera’s BAT3306 (Ph 1/3 in nsNSCLC commenced in July 2024), Amgen’s ABP 234 (Ph 3 in nsNSCLC initiated May 2024), Samsung Bioepis’ SB27 (Ph 3 in metastatic nsNSCLC commenced April 2024) and Sandoz’s GME751 (Ph 1 commenced in May 2024).

In September 2024, Shanghai Henlius Biotech received approval in China for a clinical trial of its pembrolizumab biosimilar, HLX17 and, in June 2025, Alvotech and Dr Reddy’s announced that they entered into a global collaboration and licence agreement to co-develop, manufacture and commercialise a pembrolizumab biosimilar.