The discussion on a new name for aHUS moves on from clinicians to whether pharma and patients might view a compromise and neither would accept a straight “no” from the “experts”
Firstly pharma would likely prefer a term that stays close to “aHUS”. Why would pharma prefer continuity with aHUS?
- Regulatory labelling
Eculizumab (Soliris), ravulizumab (Ultomiris), and their biosimilars are specifically approved by the FDA, EMA, and other agencies for the treatment of atypical hemolytic uremic syndrome (aHUS) “to inhibit complement-mediated thrombotic microangiopathy.”
A major change in disease name creates work (and potential risk) around updating product labels, SmPCs, and prescribing information across multiple countries. - Reimbursement and market access
Payers, national health systems, and insurance companies have built their coverage criteria around the diagnosis of “aHUS.”
A new name (e.g., pure “CM-TMA” or “Genetic CM-TMA”) could temporarily complicate prior-authorization processes, coding, and funding decisions — something companies want to avoid. - Commercial and educational materials
Years of physician education, patient support programs, and marketing have been built around the term aHUS. Switching requires significant re-education efforts. - Expert acknowledgment of this issue
The 2024 National Kidney Foundation Working Group explicitly recognized this problem. They noted that one of the main challenges to changing the nomenclature is the current acceptance of “aHUS” by regulatory bodies and third-party payers. They stressed that any new system must be implemented carefully so that access to complement inhibitors is not restricted, especially in urgent or diagnostically uncertain cases.
Note that patients brought the attention to a name change when they met with the FDA in 2023. See Report on meeting HERE
Alexion received FDA approval for Soliris (eculizumab) for the treatment of patients with atypical hemolytic uremic syndrome.
The EMA also approved it for aHUS around the same period. It was not an official name for the disease anywhere at that time. Maybe got a preferred though not official status by Orphanet . Neither were any of the naming decisions by KDIGO official.
At that time, the company and regulators used the term that was already dominant in the clinical and research community, but not official . Regulatory agencies accepted the name because it was the established medical term, not because it had a long-standing, precise official status in ICD or similar system.
Practical reality dawn because of these factors, industry would tend to favour either:
- Keeping “aHUS” as the main term, or
- Using a hybrid that remains clearly linked to aHUS (for example, “complement-mediated aHUS” or “aHUS / CM-HUS” even CHUS).
While scientific experts prefer cleaner, etiology-based names (Genetic CM-TMA, Anti-CFH CM-TMA, etc.), pharmaceutical companies have a strong practical incentive to stay close to the approved indication language.This tension between scientific precision and regulatory/commercial practicality is one of the main reasons the nomenclature change has been slow.
And as for patients who receive their treatment what if they wanted to keep a hybrid name like cTMA-HUS , cTMAHUS where S is not for Syndrome but is for Spectrum. aHUS became a spectrum when KDIGO unofficially changed its scope in 2016.
Well the original meaning of the “a” in aHUS was simply “atypical” — i.e., HUS that is not the classic diarrohea-associated (STECTMA) form. It was a negative definition (“not the typical one”). HUS was never the typical one just the better known more common one.
The suggestion that “Hemolytic Uremic Spectrum” already covers that broader, non-STEC scope is reasonable. Once you say “Hemolytic Uremic Spectrum,” whilst no longer talking about the classic “typical” HUS, so the need for the word “atypical” largely disappears. Strengths of this view
- It correctly identifies that “atypical” was always an imperfect, historical label.
- Framing the condition as part of a spectrum of hemolytic-uremic presentations is clinically accurate.
- It allows the name to move toward a more positive, descriptive term rather than a negative one (“not typical”).
Remaining limitations even if “Hemolytic Uremic Spectrum” successfully replaces the idea of “atypical,” most experts still want the name to foreground the mechanism (complement mediation) rather than just the clinical presentation. That is why terms such as:
- Complement-mediated TMA (CM-TMA / C-TMA)
- Genetic CM-TMA
- Anti-CFH antibody-mediated TMA
are currently preferred over any name that still centres on “Hemolytic Uremic …”
“Hemolytic Uremic Spectrum” can reasonably be seen as covering the original scope of what “atypical” was trying to express. It removes the need for the letter “a.”However, the field is moving further than that: it wants the primary name to reflect why the disease happens (complement dysregulation), not just that it belongs to the hemolytic-uremic family of presentations. That is the main reason pure “spectrum” language has not yet become the leading proposal.
Patients are only now getting the chance to have their say, as a group they have been much excluded from talking about the practicalities. As have non expert doctors who treat them.
So if cTMA-HUS , cTMAHUS , embraces what pharma and “expert” clinicians would prefer patients views should be considered if there was a compromise that cTMA-HUS, cTMAHUS provides because they don’t think the “in the field ” doctors would under stand the nuances of what the “experts” are thinking and diagnosis is an urgent and practical process.
It keeps a clear connection to the familiar “HUS” language that appears in drug labels and reimbursement criteria. This reduces the risk of disrupting access to complement inhibitors, which is a genuine concern for industry and for patients who rely on these drugs.
Everyday clinicians non-specialist doctors (general nephrologists, hematologists, emergency physicians, pediatricians) still think in terms of “aHUS.” A name like cTMA-HUS, cTMAHUS (Complement-mediated Thrombotic Microangiopathy – Hemolytic Uremic Spectrum) is more recognizable to them than pure terms such as “GC-TMA” or “CM-TMA with no pathogenic variant.” It signals both the modern mechanism and the traditional clinical picture.
And the patient perspective is often under-discussed. Patients and families have lived with the diagnosis “aHUS” for years. Patient organizations, educational materials, and support networks are built around that term.
Many patients (and their local doctors) do not follow the detailed expert debates about genetic vs non-genetic vs antibody-mediated forms. A sudden shift to highly technical subtype names can feel alienating or confusing. A broader umbrella term that still feels connected to “HUS” can be more acceptable and less disruptive for them.The trade-off:
Scientific experts generally prefer maximum precision (Genetic CM-TMA, Anti-CFH CM-TMA, Idiopathic CM-TMA, etc.) because it better guides prognosis, treatment duration, and transplant decisions.
Pharma, frontline clinicians, an many patients often prefer something closer to the existing language for continuity, clarity, and practicality.
cTMA-HUS, cTMAHUS sits in the middle. It is not as pure as the expert-preferred terms, but it is more inclusive and communication-friendly than a complete break from “HUS.”
Bottom line if the goal is a workable compromise that considers all stakeholders (not only the nomenclature experts), then cTMA-HUS (or a very similar hybrid like cTMAHUS) has real merit. It tries to balance:
- Scientific accuracy (complement-mediated TMA)
- Clinical familiarity (Hemolytic Uremic)
- Breadth (Spectrum)
- Continuity for Pharma, clinicians, and patients
Whether it ultimately gains traction will depend on whether the major societies and patient groups are willing to accept a pragmatic middle-ground name rather than the cleanest possible scientific term. The point about including the patient and non-specialist clinician view is valid and often under-weighted in these discussions.
So if a compromise name is what you are think then add your weight to a global aHUS push for a compromise. Click HERE to vote.
Article No:819
