GS-441524 Success Rate: What the UC Davis FIP Trial Shows

Key takeaway: GS-441524 reached a 92% success rate against Feline Infectious Peritonitis (FIP) in the UC Davis clinical trial led by Niels Pedersen and published in 2019 (PMC6435921). That figure comes from GS-441524 monotherapy delivered by daily injection across an 84-day protocol under veterinary supervision. It is the strongest evidence caregivers have when deciding whether to commit to treatment, and it is the number CureFIP builds its injectable protocol around.

Below, we explain where the 92% comes from, what it does and does not promise, how the four forms of FIP shape dosing, and how to read your own cat's progress against the data.

A cat resting comfortably at home.

What is the GS-441524 success rate for FIP?

The GS-441524 success rate for FIP is 92%, reported by UC Davis in the Pedersen 2019 field trial of cats treated with GS-441524 monotherapy (PMC6435921). That study followed cats through a defined treatment course and measured sustained remission, not a single moment of improvement.

GS-441524 is the antiviral at the core of modern FIP treatment, and it is the hero ingredient of every CureFIP injectable. The 92% figure is specific to injectable GS-441524 monotherapy, so it should never be blended with results from other protocols or products.

Since 2019, the GS-441524 approach has grown into a global standard, with 100,000+ cats treated since 2019 across the wider network. That scale is why caregivers now research providers on rigor and transparency rather than on whether antiviral treatment works at all.

What did the UC Davis FIP study actually measure?

The UC Davis FIP study (Pedersen, 2019, PMC6435921) measured whether cats with confirmed FIP achieved and held remission after a full course of GS-441524, given by daily subcutaneous injection. Remission means the disease is controlled and clinical signs resolve, with the cat returning to normal function.

The trial is important for three reasons. First, it studied real patients with naturally occurring FIP, not a laboratory model. Second, it defined success as durable remission rather than short-term relief. Third, it attached a clear number, 92%, to a disease that was previously considered almost uniformly fatal.

We are clear about what the data shows and what it does not. A 92% success rate is not a promise for any individual cat, because outcomes depend on the form of FIP, how early treatment starts, dosing accuracy, and the cat's overall condition. Your veterinarian remains the person who interprets these factors for your specific case.

Is the 92% GS-441524 success rate the same as the FIP survival rate?

The 92% figure is a success rate for durable remission in the UC Davis trial, and it is the most useful FIP survival rate reference caregivers have for GS-441524 monotherapy. Before effective antivirals, FIP survival was measured in weeks, so the shift the data represents is enormous.

Still, a trial average is not a guarantee. Some cats need dose adjustments, extended treatment, or monitoring for relapse after the course ends. For a plain-language walkthrough of the evidence base, our guide on how effective GS-441524 treatment for FIP really is breaks the research down further.

What are the four forms of FIP, and how do they affect treatment?

FIP takes four forms, wet, dry, ocular, and neurological, and each shapes the treatment plan and the GS-441524 dose. Getting the form right matters, because the dose per kilogram rises as the virus reaches harder-to-treat tissue like the eyes and central nervous system.

Each form below mirrors a row in the dosing table for CureFIP injectables. If you are still at the diagnosis stage, our guide on what to do if your U.S. vet suspects FIP explains the first steps.

Wet (effusive) FIP

Wet FIP is the effusive form, marked by fluid buildup in the abdomen or chest that can cause a swollen belly or labored breathing. It is often the fastest-moving presentation and tends to be recognized earliest because the fluid is visible on examination or imaging.

For wet FIP, CureFIP injectables are dosed at 6 mg/kg once daily, based on the UC Davis protocol (PMC6435921).

Dry (non-effusive) FIP

Dry FIP is the non-effusive form, with little or no fluid, which makes it harder to spot. Signs can include weight loss, persistent fever, lethargy, and inflammatory masses in organs.

For dry FIP, CureFIP injectables are dosed at 8 mg/kg once daily. Because the signs are subtle, cats sometimes arrive later in the disease, which is one reason some feline viruses are diagnosed too late.

Ocular FIP

Ocular FIP involves the eyes, with signs such as color changes in the iris, cloudiness, inflammation, or sudden vision problems. Because the eye is a protected site, this form needs a higher dose to reach effective drug levels.

For ocular FIP, CureFIP injectables are dosed at 10 mg/kg once daily.

Neurological FIP

Neurological FIP affects the brain and spinal cord, and signs can include wobbliness, tremors, seizures, or behavior changes. Like the eyes, the central nervous system requires the highest dose to cross into affected tissue.

For neurological FIP, CureFIP injectables are dosed at 10 mg/kg once daily.

FIP dosing by form at a glance

FIP form	GS-441524 injectable dose	Schedule	Duration
Wet / effusive	6 mg/kg	1 subcutaneous injection daily	84 days
Dry / non-effusive	8 mg/kg	1 subcutaneous injection daily	84 days
Ocular	10 mg/kg	1 subcutaneous injection daily	84 days
Neurological	10 mg/kg	1 subcutaneous injection daily	84 days

All doses above are from the CureFIP catalog and follow Pedersen et al., UC Davis (PMC6435921). Your veterinarian confirms the correct dose for your cat's weight and form.

How long is the GS-441524 protocol, and why 84 days?

The standard GS-441524 course runs 84 days, which is 12 weeks of one injection per day, seven days per week, under veterinary supervision. The 84-day protocol reflects the treatment length used in the UC Davis trial that produced the 92% success rate.

The full duration matters even when a cat looks well after a few weeks. Stopping early risks leaving virus behind, which can lead to relapse. This is also why the concentration printed on a vial is only part of the story, a point we explain in why the number on the label isn't the number that matters.

To follow progress objectively, most caregivers work with their veterinarian on periodic labs. Our guide to what your cat's blood work is really telling you during FIP treatment explains which numbers tend to move first.

Which GS-441524 injectable strengths does CureFIP offer?

CureFIP offers GS-441524 injectables in several concentrations so the volume per dose can suit cats of different weights. Higher concentrations mean a smaller injection volume, which many caregivers find easier for daily home dosing.

Product	Strength	Volume	Price
GS-441524 Antiviral Injectables	15 mg/ml	8ml	$49.00
GS-441524 Antiviral Injectables	20 mg/ml	8ml, 10ml	$69.00
GS-441524 Antiviral Injectables	30 mg/ml	8ml, 10ml	$89.00
GS-441524 Antiviral Injectables	40 mg/ml	8ml, 10ml	$119.00
GS-441524 Antiviral with Vitamin B12	20 mg/ml + B12 50mcg/ml	8ml, 10ml	$75.00
GS-441524 Antiviral with Vitamin B12	30 mg/ml + B12 50mcg/ml	8ml, 10ml	$95.00

The Vitamin B12 versions pair the same GS-441524 antiviral with added B12, which some caregivers choose when appetite and energy support are a priority. Every strength above follows the same per-form dosing and the same 84-day protocol. Your veterinarian helps you match strength to your cat's weight so daily volume stays comfortable.

Does the 92% figure apply to oral or dual antiviral treatment?

No. The 92% success rate applies specifically to GS-441524 monotherapy injectables in the UC Davis trial (Pedersen, 2019), and it should never be applied to oral or dual antiviral protocols. Different products are matched to different evidence.

For a separate dual antiviral approach that combines GS-441524 with EIDD-1931, the relevant figure is a 78.3% remission rate in previously relapsed FIP cats, reported by Li and Cheah (2025). That is a distinct study population and a distinct number, which is why the two are kept separate.

If you want to understand where the dual route fits, see our overview of dual antiviral FIP treatment for American cat owners and the reporting on the 78.3% remission study in relapsed cats. CureFIP's Cure FIP™ Oral Capsules are priced at $129.00 and dosed by weight band, and your veterinarian can advise whether an oral or injectable route suits your cat.

What should you do to give your cat the best chance?

To align with the conditions that produced strong results in the UC Davis trial, focus on early, accurate, and complete treatment. The following steps keep your plan close to the evidence.

1. Get a confirmed diagnosis and identify the FIP form with your veterinarian, since the form sets the dose.

2. Start GS-441524 as soon as FIP is confirmed, because earlier treatment generally supports better outcomes.

3. Weigh your cat regularly and adjust dosing with your veterinarian as weight changes.

4. Complete the full 84-day protocol, even if your cat looks well sooner.

5. Monitor with periodic blood work so you and your veterinarian can catch problems early.

For a broader orientation to treatment in the United States, our complete FIP treatment FAQ guide answers the practical questions caregivers ask most.

FAQ

What is the GS-441524 success rate for FIP?

The GS-441524 success rate for FIP is 92%, based on the UC Davis field trial of GS-441524 monotherapy published by Pedersen in 2019 (PMC6435921). The figure reflects durable remission across a full 84-day protocol under veterinary supervision.

Is a 92% success rate a guarantee my cat will recover?

No. A 92% success rate is a trial average, not a promise for any individual cat, and outcomes depend on the FIP form, how early treatment begins, dosing accuracy, and overall health. Your veterinarian is the right person to assess your cat's specific chances.

How long does GS-441524 FIP treatment take?

The standard GS-441524 protocol is 84 days, given as one subcutaneous injection per day, seven days per week, under veterinary supervision. Completing the full course matters even if your cat improves early, because stopping too soon raises the risk of relapse.

Does the FIP dose change depending on the form?

Yes. Using CureFIP injectables and the UC Davis protocol, the dose is 6 mg/kg for wet FIP, 8 mg/kg for dry FIP, 10 mg/kg for ocular FIP, and 10 mg/kg for neurological FIP. Your veterinarian confirms the exact dose for your cat's weight and form.

Is the 92% figure the same for oral or dual antiviral treatment?

No. The 92% figure applies only to GS-441524 monotherapy injectables (UC Davis, Pedersen 2019). A separate dual antiviral protocol combining GS-441524 with EIDD-1931 reported a 78.3% remission rate in previously relapsed cats (Li and Cheah, 2025), and the two numbers are never combined.

If you are weighing your options, we are here to help you understand the protocol, the evidence, and the products before you decide. You can explore CureFIP's FIP treatment options and then talk them through with our team and your own veterinarian, who remains your best guide for every medical decision.