Evaluating Readiness to End 
Treatment

Determining if a patient is ready to complete treatment after 84 days or after extended treatment requires taking both clinical and diagnostic information into consideration.  It is extremely important that the entire picture of the cat's health be considered rather than assigning undue weight to any one slightly anomalous value on bloodwork. (For example, a slightly high globulin value or slightly  low A:G ratio.)  Treat the cat, not the bloodwork!

Bloodwork

A CBC and chemistry panel is recommended to evaluate readiness for cessation of treatment. Ideally  the usual bloodwork markers for FIP should have returned to within normal limits.  More specifically:

  • Anemia should be resolved

  • Neutrophils should be within the normal range

  • % Lymphocytes at 20% or higher.  Lymphocytosis is often noted during and after treatment and is the effect of immune activation.  It may take months post-treatment for this to return to normal.  Lymphocytosis can be safely ignored within the context of FIP.

  • Hyperbilirubinemia resolved

  • Globulins within normal limits

  • An A/G ratio of 0.7 or higher is desirable, although some cats won't achieve this but may be cured.  An A/G level lower than 0.7 is less worrisome if it is the result of normal globulins and low (or low-normal) albumin rather than the reverse.

 

CBC and serum chemistry panels also include numerous other values and these can generally be safely ignored unless they are significantly elevated/decreased and associated with clinical signs.

Unless there is a specific concern, getting ultrasound or xrays at the conclusion of treatment is neither required nor recommended.  This is because terminal ultrasound findings small amounts of abdominal fluid, or vague irregularities in organs such as the kidneys,  spleen, pancreas, or intestines are more likely to be residual than signs of active disease.

Clinical Evaluation

The cat should be evaluated for outward manifestations of health.  For example:

  • Have neurological and ocular symptoms resolved?

    • Keep in mind, neurological and ocular FIP can leave behind some residual damage/symptoms​

  • Does the cat have a normal (or above normal) energy level?  

  • Does the cat have a normal appetite?

  • Has the cat gained weight?

If a cat does not substantially meet the above criteria, it is recommended to increase the dosage and extend treatment by a minimum of 4 weeks.  If resistance to the current antiviral is suspected, it may be desirable to switch the cat to a different antiviral treatment.  Antiviral resistance is typically indicated by either no response to the antiviral or a pattern of initial positive response followed by relapse which continues as the dose is raised progressively higher.  Aggressive dosage increases are sometimes able to overcome antiviral resistance, but large doses can complicate administration, making alternative antiviral therapies more attractive.

 

If there is concern that the cat is not ready to end treatment, but the concern is more minimal, a trial may be done at a higher dosage (or alternative antiviral) for 2 weeks at which point the cat is re-evaluated -- if the symptoms or labwork do not improve, you can more safely conclude they are not caused by active FIP disease and end treatment.  If improvement is seen, treatment should be extended for at least 2 more weeks.

Once a cat ends treatment, it is recommended that they be observed for 3 months to confirm whether the treatment has been successful.  During this time, a checkup and bloodwork are recommended every 4-6 weeks.