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The FDA is expected to decide on Imsidolimab for Generalized pustular psoriasis by December 12, 2026, under a BLA from Vanda Pharmaceuticals.
What the FDA is deciding on Imsidolimab for Generalized pustular psoriasis
The FDA is reviewing Vanda Pharmaceuticals' application to approve Imsidolimab (Quimilza) for generalized pustular psoriasis.
IL-36 receptor antibody targeting generalized pustular psoriasis flares. Vanda's August 5, 2026 quarterly release refers to the product by the proposed brand name Quimilza and reaffirmed the December 12th target action date.
Who the Imsidolimab decision matters to
Generalized pustular psoriasis (GPP) is the rarest form of psoriasis and behaves like a different disease. During a flare, painful pus-filled bumps spread across large areas of skin within a week, with fever, chills and exhaustion, and untreated flares can become life threatening.
Spevigo, the first drug built for GPP, was approved in 2022. A second IL-36 blocker, imsidolimab, has an FDA decision due December 12, 2026.
Prevalence: Roughly 2 to 7 new cases per million people a year worldwide (NORD); published estimates range from 2 to 124 per million, lower in Europe and higher in parts of Asia; about half of people with GPP also have ordinary plaque psoriasis. See our full Generalized Pustular Psoriasis page for current treatments, recruiting trials, and community resources.
How Imsidolimab works
Imsidolimab: fully humanized IgG4 monoclonal antibody that blocks interleukin-36 receptor signaling. Our full Imsidolimab profile covers how it works, side effects in plain language, and its trial history.
What an approval or a rejection of Imsidolimab would mean
An approval starts a second race rather than ending the first one: specialty pharmacy setup, insurance review, and patient assistance typically take weeks even when everything goes right. Our guide to the 90 days after a rare disease approval explains the timeline and the moves families can make on day 1.
A complete response letter would mean the FDA declined to approve in the application's current form. The letter describes what the FDA wants addressed, and the company then decides whether to resubmit, run more studies or stop. Either way, this page updates with the outcome and what it means.
Where Generalized Pustular Psoriasis treatment stands today
Read our full Generalized Pustular Psoriasis treatment summary
Spevigo (spesolimab), an antibody that blocks the IL-36 receptor, was approved on September 1, 2022 as the first treatment designed for GPP flares, and a new indication was added on March 18, 2024; the current label covers an intravenous dose for active flares and a monthly under-the-skin injection to reduce the risk of flares, in adults and children 12 and older weighing at least 40kg.
In the flare trial, 54% of people given the intravenous dose had no visible pustules after 1 week, versus 6% on placebo (19 of 35 patients compared with 1 of 18). In the prevention trial, 27 of 30 people on the monthly injection stayed flare-free for 48 weeks, compared with 15 of 31 on placebo.
Before Spevigo, flares were managed with older drugs borrowed from plaque psoriasis, including cyclosporine, acitretin, methotrexate and biologics that block TNF, IL-17 or IL-23.
The next decision is imsidolimab, a second IL-36 receptor antibody licensed by Vanda Pharmaceuticals from AnaptysBio. In the GEMINI-1 and GEMINI-2 trials, a single intravenous dose cleared or almost cleared the skin in 53% of patients at week 4 versus 13% on placebo, and monthly doses kept patients flare-free through roughly 2 years of follow-up.
The FDA accepted the application in February 2026 with a target action date of December 12, 2026.
Ask your dermatologist ahead of time which centers near you take part in GPP studies; the National Psoriasis Foundation's Patient Navigation Center (800-723-9166) can also point you to specialists and to the CorEvitas GPP registry.
The Generalized Pustular Psoriasis page has every treatment and trial →Meanwhile, 3 Generalized Pustular Psoriasis studies are open or about to open
Whatever the FDA decides here, research on Generalized Pustular Psoriasis does not stop. Of these, 1 tests a treatment; the others follow patients over time. The most recently updated:
We'll email you when the decision is public, with what it means in plain language, and when new trials open for Generalized Pustular Psoriasis. Unsubscribe anytime.
- Trial Alerts, when a new trial opens or a trial changes
- Disease Updates, FDA decisions and condition news, usually 1 or 2 emails a month
Frequently asked questions
When will the FDA decide on Imsidolimab?
The FDA's target date (PDUFA date) for Imsidolimab in Generalized pustular psoriasis is December 12, 2026.
Who disclosed it: Vanda Pharmaceuticals. The FDA does not publish these dates.
Can it move: the FDA can act early, and a major amendment to the application can push the date back 3 months.
Source: Vanda announcement
What is Imsidolimab being reviewed for?
Vanda Pharmaceuticals submitted a BLA for Imsidolimab in Generalized pustular psoriasis.
What to know: IL-36 receptor antibody targeting generalized pustular psoriasis flares. Vanda's August 5, 2026 quarterly release refers to the product by the proposed brand name Quimilza and reaffirmed the December 12th target action date.
How it works: Fully humanized IgG4 monoclonal antibody that blocks interleukin-36 receptor signaling.
More: the Imsidolimab drug page explains it in plain language.
Is there already an FDA-approved treatment for Generalized Pustular Psoriasis?
Trial Friend does not have pages yet for the FDA-approved drugs for Generalized Pustular Psoriasis, if there are any. The Generalized Pustular Psoriasis page checks FDA drug labels for approved treatments.
Check: the Generalized Pustular Psoriasis page also searches FDA drug labels for approved treatments.
What did the Imsidolimab trials show?
GEMINI-1 and GEMINI-2 were the pivotal efficacy studies, run in the United States, France, Spain, Poland, Turkey, Malaysia, Thailand, Georgia, Tunisia, Taiwan and Morocco. A single intravenous dose of imsidolimab led to rapid clearance, with 53% of patients reaching clear or almost clear skin on the GPP Physician Global Assessment (GPPPGA 0/1) at week 4 compared with 13% on placebo.
More: the Imsidolimab drug page has the full trial history and sources.
What are the side effects of Imsidolimab?
Vanda describes the safety profile in GEMINI-1 and GEMINI-2 as favorable with a low incidence of anti-drug antibodies, and the full results were published in NEJM Evidence in April 2026. The company's announcements do not list individual adverse event rates, and there is no US label yet.
More: the Imsidolimab drug page has the safety details reported so far.
Can I get Imsidolimab before the FDA decides?
Usually only through a clinical trial or an expanded access program, and the company decides whether to offer one.
Trials: 3 Generalized Pustular Psoriasis studies are open or about to open, 1 of them testing a treatment. See them.
Check your fit: Match Me compares your details with every open trial.
Expanded access: your doctor can ask Vanda Pharmaceuticals directly. Registered programs are listed on ClinicalTrials.gov.
How much will Imsidolimab cost?
Vanda Pharmaceuticals has not announced a price. Drugmakers usually set it around approval.
Help paying: drugmaker programs and charity funds usually open at launch.
Find help: the patient assistance finder lists programs by insurance type.
What happens after the Imsidolimab decision?
This page updates with the outcome the day it is announced.
If approved: getting the drug still takes time. Specialty pharmacy setup, insurance review and patient assistance often take weeks. Our guide covers what families can do on day 1.
If not approved: a complete response letter means the FDA declined the application in its current form. Many are about manufacturing or how data were presented, and companies often resubmit.
Where this date comes from
The FDA does not publish PDUFA dates; companies disclose them. This one comes from Vanda announcement. Dates can move, and the FDA can act early or late. This page rechecks against our calendar, which is re-verified daily.