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Emerging treatmentsLarge study to confirm benefit and safetyGreek status differs by study

Orelabrutinib: Phase 3 studies in two forms of progressive MS

Published by MyelinWatch:

Study sponsor
Zenas BioPharma (USA), LLC

Orelabrutinib

Greek centres and contacts ↓

In plain words

An experimental drug tested in two large studies: one in primary progressive and one in non-active secondary progressive multiple sclerosis. They check whether it slows the worsening of disability; there are no results yet, and some participants receive a placebo. In Greece the status differs between the two studies (Greek enrolment for one was still listed as pending), so each centre must confirm enrolment and eligibility.

What is being studied

Orelabrutinib is an experimental drug designed to inhibit BTK, a protein involved in immune-cell signalling. Zenas BioPharma (USA), LLC sponsors studies of orelabrutinib in primary progressive MS (NCT07067463) and non-active secondary progressive MS (NCT07299019). The studies assess whether treatment affects disability worsening.

Research stage

Large study to confirm benefit and safety

The two trial records list overall recruitment; Greek country participation differs by study and is explained below.

What we know so far

ClinicalTrials.gov lists both Phase 3 studies overall as accepting participants, with about 705 and 990 planned participants and no posted results (both records updated 27 October 2026). At the 25 October CTIS check, Greece was listed as accepting participants for PriMroSe, with seven Greek site listings. For Monarch, the EU register (Greek entry last updated 16 October) still listed Greek recruitment as pending at the 28 October check, with six Greek site listings, while the ClinicalTrials.gov record now lists an Athens centre, recorded as "Errikos Dunant Hospital" and matching the Henry Dunant Hospital Center, as accepting participants. The two registers were updated on different dates. Neither source establishes benefit, safety, myelin repair, an available place or individual eligibility at a Greek centre.

What this means for patients today

A person with primary progressive MS may wish to discuss PriMroSe because it tests whether orelabrutinib can delay disability progression; taking part helps answer that question. No PriMroSe results are posted, and participants are assigned to orelabrutinib or placebo, so neither receiving the experimental drug nor personal benefit is assured. At the 25 October CTIS check, Greece was listed as accepting participants for PriMroSe. A person with non-active secondary progressive MS may wish to ask about the separate Monarch study, which also compares orelabrutinib with placebo and has no posted results: ClinicalTrials.gov lists an Athens centre, recorded as "Errikos Dunant Hospital" (the Henry Dunant Hospital Center), as accepting participants, although the EU register still listed Greek recruitment as pending at the last update of its Greek entry (16 October). An individual centre must confirm current enrolment and eligibility; study access is not approved treatment or evidence of Greek commercial availability or reimbursement. No established approved treatment has been proven to reliably restore myelin in MS.

PriMroSe — primary progressive MS

At its 25 Oct 2026 check, the EU trial register listed Greece as accepting participants for this study and included seven Greek site listings. No per-site recruitment status, available place or individual eligibility was shown in that register. Confirm current participation with the relevant centre. The ClinicalTrials.gov record lists overall recruitment but no Greek location rows; that absence applies only to that record.

Chaidari

University General Hospital Attikon General Hospital Of West Attica H Agia Varvara

2nd Department of Neurology NKUA

Address
Rimini 1, 124 61, Greece
Study contact
Prof. Georgios Tsivgoulis

EU trial register ↗ · Source checked:

Cholargos

Metropolitan General Hospital Healthcare Facilities Operation And Management Single Member S.A.

3rd Neurology Clinic

Address
Leoforos Mesogeion 264, 155 62, Greece
Study contact
Dr. Dimitrios Papadopoulos

EU trial register ↗ · Source checked:

Larissa

General University Hospital Of Larissa

Department of Neurology

Address
P. O. Box 1425, 411 10, Greece
Study contact
Prof. Efthimios Dardiotis

Postal box; this is not a visit address.

EU trial register ↗ · Source checked:

Thessaloniki

St. Luke's Hospital S.A.

Multiple Sclerosis Unit - Neurology Department

Address
Harilaou Trikoupi Str. 3, 552 36, Greece
Study contact
Prof. Anastasios Orologas

EU trial register ↗ · Source checked:

Monarch — non-active secondary progressive MS

At its 28 Oct 2026 check, the EU trial register (Greek entry last updated 16 Oct 2026) listed recruitment in Greece as pending for this study and included six Greek site listings. No per-site recruitment status, available place or individual eligibility was shown in that register. Confirm current participation with the relevant centre. The ClinicalTrials.gov record, updated 27 Oct 2026, lists "Errikos Dunant Hospital" in Athens (postcode 115 26) as accepting participants; this matches the Henry Dunant Hospital Center listed below. The two registers were updated on different dates.

Larissa

General University Hospital Of Larissa

Neurology Department

Address
P. O. Box 1425, 411 10, Greece
Study contact
Prof. Efthimios Dardiotis

Postal box; this is not a visit address.

EU trial register ↗ · Source checked:

Chaidari

University General Hospital Attikon General Hospital Of West Attica H Agia Varvara

2nd Department of Neurology

Address
Rimini 1, 124 61, Greece
Study contact
Prof. Georgios Tsigvoulis

EU trial register ↗ · Source checked:

Cholargos

Metropolitan General Hospital Healthcare Facilities Operation And Management Single Member S.A.

3rd Neurology Clinic

Address
Leoforos Mesogeion 264, 155 62, Greece
Study contact
Dr. Dimitrios Papadopoulos

EU trial register ↗ · Source checked:

Treatment or approach
Orelabrutinib — an experimental treatment for progressive MS
Where the study is running
CTIS checks: PriMroSe (25 October 2026) — Greece accepting participants, seven Greek site listings; Monarch (28 October 2026; Greek entry last updated 16 October) — Greece recruitment pending, six Greek site listings. CTIS shows no site-specific recruitment status for either study. The ClinicalTrials.gov records, both updated 27 October 2026, list no Greek location for PriMroSe and one for Monarch: "Errikos Dunant Hospital", Athens, listed as accepting participants, which matches the Henry Dunant Hospital Center in the CTIS list.
Source: EU Clinical Trials Information System — official EU clinical-trial register ↗Source: EU CTIS — Monarch, Greek country recruitment pending ↗ Source: ClinicalTrials.gov — PriMroSe, NCT07067463 ↗ Source: ClinicalTrials.gov — Monarch, NCT07299019 ↗
Published by MyelinWatch
Last substantive MyelinWatch update

Programme updates — newest research developments first

  1. Registered Phase 3 studies in people; no results postedResearch event/source date:

    Two Phase 3 orelabrutinib studies for progressive MS are listed as accepting participants

    NCT07067463, for primary progressive MS, was updated on 22 September 2026 and plans about 705 participants. NCT07299019, for non-active secondary progressive MS, was updated on 23 September 2026 and plans about 990 participants. Both Phase 3 studies, sponsored by Zenas BioPharma (USA), LLC, are listed as accepting participants. Neither registry record has posted results. These dates mark registry updates, not the start of the studies or recruitment.

    Source: ClinicalTrials.gov — official clinical-trial registry ↗Source: ClinicalTrials.gov — NCT07067463, primary progressive MS; update posted 22 September 2026 ↗