GS441 treatment Process Dr. Pedersen's case study determined that the successful course of treatment for GS441 was 12 weeks of daily dosing. Once the blood tests and diagnosis returned to normal, some owners stopped treatment. However, the few cats that relapsed were among those that stopped before the 12-week regimen. Because the treatment process is emotionally and financially taxing, most owners currently using GS choose to pursue the full 12 weeks,To ensure the highest likelihood of success. Cats that received a full 12 weeks and remained asymptomatic for 90 days after the end of treatment were officially cured of FIP. GS441 is available in both injectable and pill form as of June 2019. Both are given daily and the dosage depends on the weight of the cat.