A Wrestling Coach's Textbook History, Against an MRI That Won't Cooperate
His story is about as classic as inflammatory back pain gets, and everyone in the room believes him. The guideline's biologic threshold was never built to run on belief — it runs on an MRI and a CRP that both landed just short.
Tobias H. coaches high school wrestling and wrestled competitively himself through college, which is part of why it took him two years to bring his low back pain to a doctor — "sore" was just what his body had always felt like. What finally changed his mind was the pattern, not the intensity: pain that wakes him around 3 a.m., stiffness that takes a full hour of moving around the gym before it loosens, and real improvement with exercise rather than rest, a combination that reads, almost point for point, like the textbook description of inflammatory back pain his rheumatologist has used to teach the concept to residents. He is HLA-B27 positive, meets the ASAS clinical arm for axSpA classification, and his BASDAI has held at 6.1 despite two adequate NSAID trials.
What he doesn't have is the objective finding biologic eligibility for non-radiographic axSpA is specifically built around. His CRP has come back at 4.8 mg/L against an upper limit of normal of 5.0 — technically within range, close enough that a single repeat draw on a different day could plausibly land on either side of that line. His sacroiliac MRI, read independently by two radiologists, shows changes short of the bone-marrow-edema pattern required for a positive reading under ASAS criteria: real, but equivocal. C-axSpAnd, the trial that established certolizumab's efficacy in nr-axSpA and won it the indication, required objective inflammation to enroll at all — and its stratified analysis is genuinely reassuring for patients carrying only one marker, with benefit holding in the MRI-positive/CRP-normal and MRI-negative/CRP-elevated groups as well as in those with both. Tobias carries neither, which places him not at the weak end of the studied population but outside it, and outside the qualifier written into the drug's own label. He was blunt when this was explained to him, having watched enough of his own wrestlers get held out over a borderline weigh-in to find the parallel almost funny. What the room could not tell him is what the trial would have found in someone like him, because it never enrolled anyone like him: the question is not answered weakly, it is unasked.
Believing him and treating him aren't the same threshold
His CRP is 4.8 against an upper limit of 5.0, and his MRI is equivocal rather than positive. The pivotal evidence for biologic efficacy in nr-axSpA, C-axSpAnd, didn't merely enrich for patients with objective inflammation — it required at least one marker as an entry criterion. He has neither. Starting him today isn't treating at the uncertain edge of that evidence, it's treating off it entirely, and the label's own wording carries the same qualifier. I'd repeat the CRP and get a follow-up MRI in eight to twelve weeks before committing to a biologic.
I'd push back on treating 4.8 versus 5.0 as a meaningful biological difference. Inflammation is a continuous process; a single decimal point on one blood draw isn't a switch flipping from "no disease" to "disease." He has nocturnal pain, real improvement with exercise, and has already failed two adequate NSAID trials. That clinical picture is doing more work here than a CRP value close enough to the threshold that a different lab on a different day could easily land it on the other side.
I'm not arguing the threshold is meaningless — I'm arguing it's being read with more precision than the underlying biology actually has, in a patient whose overall picture is about as clear as inflammatory back pain gets.
I don't think either of you needs to fully win this one, but I want to be exact about what the trial does and doesn't say, because it cuts against both of you. Its stratified analysis found benefit whether the marker was the MRI or the CRP — one was enough, which undercuts any argument that he needs to cross both. What it cannot tell us is anything at all about someone carrying neither, since that patient was excluded at screening. So the honest answer isn't "the evidence predicts a weaker response" — it makes no prediction for him. I'd start certolizumab now, say plainly that we are extrapolating past the studied population rather than working at its edge, and set a genuine checkpoint at 12 weeks instead of the usual longer window — when there's no trial to borrow a prior from, his own early response is the only evidence we're going to get.
Agreed: start certolizumab pegol now, continue NSAIDs, repeat CRP and obtain a follow-up MRI in parallel, and hold a genuine 12-week checkpoint to assess response given his borderline objective findings.
Not agreed: what should happen at 12 weeks if response is partial rather than clearly present or clearly absent. The first rheumatologist would want repeat objective testing to have resulted by then to help interpret an ambiguous response; the clinical pharmacologist would weight his subjective report and functional improvement more heavily than any single follow-up lab or imaging result, regardless of how the numbers land.