Thor

Thor, a 9 month old domestic short hair kitten presented with a 2 week history of vomiting, weight loss,  progressive ataxia and generalized weakness, which had progressed to nonambulatory paraparesis.  A pronounced physiologic nystagmus and intermittent rotary nystagmus was also noted at the initial exam. Withdrawals,  superficial pain and menace responses were intact.

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Hematological and serum biochemistry abnormalities at the initial exam included lymphopenia, (718 uL; reference interval 850-5850 uL) mild hypoalbuminemia, and an A/G ratio of 0.4 (albumin, 2.5 g/dL; reference interval, 2.6‐3.9 g/dL; globulin, 5.6 g/dL; reference interval, 3.0‐5.9 g/dL).  Tests for Toxoplasmosis, FeLV and FIV were negative, and FCoV antibody titer was positive at 1:6400.  

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Thor declined rapidly after exam, with progressive paresis and dysphagia.  Uveitis was also noted in his right eye.

 

Treatment with GS-441524 was initiated at 25 mg/kg BID, for the first week, and then weaned down to 25 mg/kg SID for the remaining 11 weeks.  A higher dose than the standard starting neurological FIP dose was chosen due to Thor's critically worsening condition.

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Within 24 hours of starting treatment with GS-441524, Thor began to show improvement in neurologic signs and ability to move limbs.  Within 4 days, Thor regained crude ambulatory ability which progressively improved throughout treatment, most rapidly within the first 4 weeks.  At about 8 weeks Thor was nearly clinically normal, with minor residual gait and movement changes which appear to be permanent.

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After 6 weeks of treatment previously noted hematological and serum biochemistry abnormalities had normalized. (Lymphocytes, 2875 uL; reference interval 850-5850 uL; albumin, 3.0 g/dL; reference interval, 2.6‐3.9 g/dL; globulin, 3.6 g/dL; reference interval, 3.0‐5.9 g/dL; A/G ratio: 0.8)

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Other than some mild gait abnormalities which appear to be permanent residual effects, Thor is clinically normal as of 1 year post treatment.