The powerful modern psoriasis drugs can only be given by injection
The old claim turned out to be wrong and was rejected by evidence.
TaughtThe biologics that clear moderate-to-severe psoriasis are large antibody proteins. Swallow one and your gut digests it like food, so they only work as injections. A pill that targets the same pathway is not chemically possible.
NowOn 18 March 2026 the FDA approved Icotyde (icotrokinra), the first oral IL-23 pathway drug for plaque psoriasis. It is a small engineered peptide designed to survive the gut and block the same target the injected biologics hit.
What actually happened
The teaching wasn't foolish; it was true of antibodies, which really are too big and fragile to take by mouth. The workaround is that icotrokinra is not an antibody. It is a small peptide built to be orally stable, blocking the IL-23 receptor rather than mopping up the protein with a giant Y-shaped molecule. Same pathway, radically different chemistry, and it goes in as a once-daily pill.
Injected biologics still tend to clear skin more completely for the toughest cases, so 'disproved' applies to the categorical claim, not to a promise that the pill beats every needle. What broke is the flat statement that hitting this pathway requires an injection. It doesn't anymore; a swallowable version exists.
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Who was taught this
Still standard through 2026, so anyone who finished school between 1950 and 2026 learned the earlier version.