Therapeutic Effects of Mutian® Xraphconn on 141 Client-Owned Cats with Feline Infectious Peritonitis Predicted by Total Bilirubin Levels

Abstract

Feline infectious peritonitis (FIP) is a fatal disease caused by feline coronavirus or its variant, referred to as the FIP virus. Recently, favorable treatment outcomes of the anti-viral drug Mutian® Xraphconn (Mutian X) were noted in cats with FIP. Thus, the therapeutic efficacy of Mutian X in cats with FIP must be explored, although the predictors of therapeutic success remain unknown. In the present study, we administered Mutian X to 141 pet cats with effusive FIP following initial veterinarian examinations. Of these, 116 cats survived but the remaining 25 died during treatment. Pre-treatment signalment, viral gene expression, and representative laboratory parameters for routine FIP diagnosis (i.e., hematocrit, albumin-to-globulin ratio, total bilirubin, serum amyloid-A, and α1-acid glycoprotein) were statistically compared between the survivor and non-survivor groups. The majority of these parameters, including hematocrit, albumin-to-globulin ratio, serum amyloid-A, α1-acid glycoprotein, and viral gene expression, were comparable between the two groups. Interestingly, however, total bilirubin levels in the survivor group were significantly lower than those in the non-survivor group (p < 0.0001). Furthermore, in almost all surviving cats with effusive FIP (96.6%, 28/29), the pre-treatment total bilirubin levels were below 0.5 mg/dL; however, the survival rate decreased drastically (14.3%, 1/7) when the pre-treatment total bilirubin levels exceeded 4.0 mg/dL. Thus, circulating total bilirubin levels may act as a prognostic risk factor for severe FIP and may serve as the predictor of the therapeutic efficacy of Mutian X against this fatal disease.

Prognostic Prediction for Therapeutic Effects of Mutian on 324 Client-Owned Cats with Feline Infectious Peritonitis Based on Clinical Laboratory Indicators and Physical Signs

“…Mutian X was obtained from Mutian Life Sciences Co., Ltd. (Nantong, China). Based on previous studies, the main active ingredient of Mutian X is GS-441524, and the Mutian X 100 mg formulation includes 5 mg of GS-441524 [ 16 , 17 ]. The active ingredient of the injectable product, designated as Mutian II, has not yet been confirmed by third parties, but is presumably identical to that of Mutian X for oral administration.…”

“…Between June 2019 and December 2021, 161 cats diagnosed with mixed-type FIP and 163 cats diagnosed with dry-type FIP at our hospital were included in the study. Mutian X was administered to the cats as described previously [ 17 ]. To put it briefly, immediately after the initial FIP diagnosis, Mutian was administered at q24h for mixed-type FIP at 150 mg/kg in the early to middle disease stages or at 200 mg/kg in the late stage.…”

“…If oral administration was difficult owing to gastrointestinal dysfunction or FIP onset, such as an inability to absorb nutrients, subcutaneous administration was performed at the same dose. The drug was administered on a regular basis and on an empty stomach [ 17 ]. Each patient underwent a standard drug administration protocol for 84 days, followed by a 3-month observation period; stable cases with no apparent deterioration in quality of life were regarded as being in remission [ 17 ].…”

“…The main drug component of Mutian X, GS-441524, exerts a remarkable therapeutic effect on FIP, including the wet type [ 14 , 15 , 16 ]. We previously administered Mutian X to 141 cats with wet-type FIP, observed its promising therapeutic effect, and confirmed remission in approximately 82% of the cats [ 17 ]. Furthermore, we showed that its effect can be predicted using circulating bilirubin levels as a prognostic indicator prior to treatment initiation [ 17 ].…”

“…We previously administered Mutian X to 141 cats with wet-type FIP, observed its promising therapeutic effect, and confirmed remission in approximately 82% of the cats [ 17 ]. Furthermore, we showed that its effect can be predicted using circulating bilirubin levels as a prognostic indicator prior to treatment initiation [ 17 ]. In the present study, we determined the therapeutic effect of Mutian administration on dry and mixed types of FIP, and predicted its effect by analyzing various clinical diagnostic parameters before administration.…”