Current Takeaway
Daratumumab is an anti-CD38 monoclonal antibody that depletes plasma cells, the immune cells responsible for long-lived antibody production. In ME/CFS, it is being investigated to determine if a patient subgroup has symptoms sustained by autoantibodies or other plasma-cell-mediated pathways. The research sequence progressed from an uncontrolled ten-patient open-label pilot to the registry of the randomized ResetME Phase II trial, followed by the peer-reviewed publication of the pilot findings.
An update from the ongoing ResetME trial reported that 38 of the target 66 patients have been enrolled, with 17 completing initial follow-up, while pilot follow-up data demonstrated a correlation between clinical improvement and reductions in autoantibody profiles. However, because the trial remains blinded and recruitment is incomplete, these findings do not establish clinical efficacy. Additionally, the reporting of a serious adverse event involving hospitalization for symptom worsening underscores that safety and tolerability remain unproven.
Why This Matters
Testing a concrete immune-treatment hypothesis (rather than only describing associations) helps determine whether a biologically defined, treatment-responsive subgroup exists in ME/CFS. If the ResetME trial is positive, it would validate this pathway; if negative, it will narrow the field by testing one of the more specific plasma-cell-targeting theories under placebo control.
State of Evidence
- Established:
- A small open-label pilot demonstrated the safety and feasibility of daratumumab in ten female ME/CFS patients, with six achieving marked clinical improvement.
- The follow-up ResetME randomized Phase II trial was registered and has enrolled 38 of its target 66 participants.
- Clinical responders in pilot follow-up evaluations show post-treatment reductions in autoantibody profiles (autoreactome).
- Plausible but early:
- The pilot’s response pattern, NK-cell association, and post-treatment autoantibody reductions support the hypothesis of an antibody-mediated disease subgroup.
- Not established:
- Efficacy and safety of daratumumab for ME/CFS are not established; the ResetME trial is still ongoing and remains blinded.
- Key limitations:
- The initial pilot was small (10 participants) and limited to female patients.
- The ResetME trial uses strict enrollment criteria, including a minimum baseline Natural Killer (NK) cell threshold (>125 x 10^6/L), limiting generalizability.
- A serious adverse event involving hospitalization due to symptom worsening has been reported, requiring careful supervision.
- Conference updates and recap videos provide incomplete data until the full trial dataset is analyzed and published.
Timeline
Before 2025-06-01 - Open-label pilot generates the initial signal
The Bergen group conducted an open-label daratumumab pilot in ten female ME/CFS patients, reporting that six participants achieved marked and sustained clinical improvement with physical function scores rising from an average of 32.2 to 78.3. This clinical signal suggested that targeting CD38 on long-lived plasma cells could deplete autoantibody-producing cells that are unaffected by standard B-cell therapies like rituximab, pointing toward a possible autoimmune subgroup. However, due to the small, open-label, and all-female cohort, the study cannot distinguish the drug’s therapeutic effect from placebo responses, regression to the mean, or selection effects, and the association between baseline Natural Killer (NK) cells and clinical response remains an unvalidated stratifying hypothesis rather than a proven biomarker.
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2025-06-01 - ResetME randomized trial registered
The ResetME Phase II clinical trial was registered as a randomized, double-blind, placebo-controlled study to evaluate the efficacy and safety of subcutaneous daratumumab (combined with hyaluronidase) compared to placebo in 66 moderate to severe ME/CFS patients aged 18 to 64. This trial establishes a rigorous, placebo-controlled framework to validate the pilot’s plasma-cell depletion hypothesis and uses a specific inclusion threshold for baseline NK cells (>125 x 10^6/L) to select the patient subset hypothesized to respond. As a trial registration, it does not confirm the feasibility, safety, or efficacy of the intervention in a controlled cohort.
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2025-07-09 - Pilot paper published
The Bergen pilot study was formally published in a peer-reviewed journal, providing the primary publication of the design, safety data, and the response patterns observed in the ten-patient cohort. Peer-reviewed publication subjects the preliminary findings to scientific scrutiny, establishing a referenceable baseline for the drug’s mechanism of action and the reported NK-cell responder correlation. However, the publication of these pilot results does not overcome the inherent limitations of the open-label design, nor does it establish safety or efficacy in a wider patient population.
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2026-05-10 - ResetME trial progress and autoantibody profiles presented at conference
At the ME/CFS Research Foundation Conference 2026, presenter Øystein Fluge provided an update titled ‘ResetME: A Randomized, Placebo-controlled Study of Daratumumab in ME/CFS’, reporting that the ongoing trial has enrolled 38 of its target 66 participants, with 17 completing the initial 8-week follow-up, and shared pilot follow-up data showing larger decreases in autoantibody profiles (autoreactome) among clinical responders. This progress provides early evidence of trial execution and additional mechanistic support for the plasma-cell depletion hypothesis by correlating clinical improvement with reduction in autoantibodies, while also highlighting the necessity of close clinical supervision due to a reported serious adverse event involving a brief hospitalization for symptom worsening. Because the trial remains blinded, these updates do not establish the clinical efficacy or final safety profile of daratumumab in the randomized cohort.
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