Adult CAH With Bone Loss on Supraphysiologic Steroids: Adding Crinecerfont
A single patient whose glucocorticoid dose has never been reducible without losing androgen control, tested against a genuinely new drug with real trial evidence but limited real-world experience.
Bianca R., a 29-year-old classic congenital adrenal hyperplasia patient, has been on supraphysiologic glucocorticoid dosing since infancy — the accepted, decades-old strategy for suppressing the adrenal androgen excess her 21-hydroxylase deficiency drives, at a real, known cost. Her bone density scan this year showed a T-score of -2.1 at the lumbar spine, new since her last scan three years ago, and she has gained eighteen pounds despite no change in diet, both patterns her endocrinologist attributes honestly to years of dosing above physiologic replacement rather than to anything else. Reducing her glucocorticoid dose the conventional way has never worked without her androstenedione climbing back into a range that brought hirsutism and irregular cycles within weeks — the dose that suppresses her androgens and the dose that protects her bones and metabolism have simply never overlapped.
Crinecerfont, approved in December 2024 as the first new CAH treatment in seventy years, works through a genuinely different mechanism — blocking the CRF1 receptor to reduce ACTH drive directly, rather than suppressing the adrenal gland with more glucocorticoid — and the pivotal CAHtalyst Adult trial found it allowed a 27% reduction in daily glucocorticoid dose while maintaining androstenedione control, against a 10% dose increase in the placebo group over the same 24 weeks; 63% of treated patients reached a physiologic glucocorticoid dose. That is real, randomized evidence for exactly the two things Bianca has never been able to have together. It is also a drug approved barely over a year ago, with a wholesale cost around $38,000 for a 30-day supply, and long-term safety data that, by definition, do not yet exist the way three decades of glucocorticoid experience does.
Endocrinology follow-up, discussing crinecerfont
Her bone density and weight are both moving in the wrong direction on the only approach we've ever had, and every attempt to lower her glucocorticoid dose has failed the same way — androgens climb back within weeks. CAHtalyst Adult found crinecerfont let patients reduce dose by 27% while keeping androstenedione controlled. That's a real trial result matching her exact problem. I'd start it.
I'd want real caution built into how we start it. This drug is barely a year past approval — long-term safety data simply don't exist yet, by definition, the way thirty years of glucocorticoid experience does. Its own labeling specifically warns about acute adrenal insufficiency risk if the glucocorticoid dose comes down too fast during the transition. That's not a reason to avoid it, but it is a reason the titration needs to be genuinely careful, not just "start and reduce."
I'm not arguing against trying it for her — I'm arguing the caution belongs in the monitoring plan, not in delaying a treatment her current regimen has already failed to provide.
I think you're both actually agreeing on the plan, not disagreeing about whether to try it. Start crinecerfont, hold her glucocorticoid dose steady initially and reduce it per the labeled guidance that came with the CAHtalyst program, and reduce gradually with morning cortisol and androstenedione checked at each step. Given how documented her bone and metabolic harm already is, and how consistently the conventional approach alone has failed her, that's a reasonable trial with real safeguards, not a leap of faith.
Agreed: start crinecerfont with glucocorticoid held steady initially, then reduced gradually per the labeled dose-reduction guidance, with cortisol and androstenedione checked at every step.
Not agreed: how long to continue monitoring at this intensity once her dose stabilizes. The pharmacologist wants sustained close monitoring for at least a year given the drug's novelty; the endocrinologist would space out visits sooner once her numbers show a consistent, expected pattern, reasoning that indefinite intensive monitoring has its own real burden.