Celltrion advances Keytruda & Darzalex biosimilars

Korea's Celltrion just moved two of the biggest oncology biosimilar opportunities on the planet a step forward. On 7 September 2026, it cleared regulators in the US and Korea to amend the Phase 3 protocols for:

CT-P51 — a biosimilar of Keytruda (pembrolizumab) , MSD's immuno-oncology blockbuster. The global Phase 3 will enrol 220 patients with previously untreated metastatic non-squamous NSCLC, comparing CT-P51 head-to-head with Keytruda over a two-year treatment period. (The US amendment took effect 5 Sep, via the FDA's 60-day IND review.)

CT-P44 — a biosimilar of Darzalex (daratumumab) , the multiple-myeloma antibody. Korea's MFDS approved the amended Phase 3 protocol; the trial will run two years in 394 patients with relapsed/refractory multiple myeloma, testing CT-P44 against Darzalex Faspro (the subcutaneous form) alongside lenalidomide and dexamethasone.

The honest caveat: both remain in Phase 3 — these are protocol clearances, not marketing approvals or trial wins. Celltrion still has to demonstrate similarity and clear full approval. But the direction is unmistakable: Celltrion is systematically queuing up biosimilars of the world's highest-value oncology brands.

Why this matters for MENA pharma — the opportunity

Here's the read for our region, and it's a direct one:

These are exactly the molecules MENA will want to localize next — and Celltrion is already a MENA partner. In October 2025, Celltrion signed with Hikma for exclusive commercialization of six biosimilars across MENA (part of a relationship already spanning Vegzelma, Yuflyma, Truxima, Remsima and more). CT-P51 (pembrolizumab) and CT-P44 (daratumumab) are the natural next candidates to flow down that same channel once approved. A MENA player with an early relationship to Celltrion is positioned at the front of the queue for two future blockbusters.

The patent-cliff timing is the whole opportunity. Keytruda — the world's top-selling drug — faces its key patent expiries around 2028 , and Darzalex follows later this decade. Biosimilar developers are racing to be ready the day exclusivity lapses. For MENA, that means a narrow but high-value window : the regional champion that secures rights to a Keytruda or Darzalex biosimilar before approval locks in access to two of the largest oncology markets in the region — cancer being MENA's most acute unmet need — at a fraction of originator cost.

It fits the pattern our tracker keeps surfacing. Asian innovators (Korea's Celltrion, China's Bio-Thera, Henlius, Junshi) develop and manufacture; MENA champions (Hikma, Avalon, Jamjoom, SVAX) take registration, market access and increasingly local manufacturing. Celltrion's CT-P51/CT-P44 progress is fresh supply entering that pipeline.

The action item for a MENA BD desk: map which Keytruda/Darzalex biosimilars (Celltrion's CT-P51/CT-P44, plus Bio-Thera's BAT3306, Formycon's FYB206, Henlius's HLX17) are un-licensed in MENA — and move before the 2028 cliff, not after.

Bottom line: not a deal today, but a signal of what's licensable tomorrow. The originators' patent cliff is becoming the region's access opportunity — and the biosimilars clearing Phase 3 now are the ones MENA should be negotiating for today.