EXPERIMENTAL TREATMENT OF EQUINE SARCOID USING A XANTHATE COMPOUND AND RECOMBINANT HUMAN TUMOR-NECROSIS-FACTOR-ALPHA

A xanthate compound with antiviral and antitumoural activities, tricyc lodecan-9-yl-xanthogenate (D609) in combination with the potassium sal t of the lauric acid (KC12) and, in a further investigation, the above mentioned substances together with recombinant human TNF alpha (rh-TN F alpha), were tested on equine sarcoid rumours for therapeutic effica cy. A pilot investigation on 5 healthy horses showed that the compound s were well-tolerated; apart from a local, temporary oedema at the inj ection site, no other clinical symptoms were observed after subcutaneo us administration of volumes from 0.1 to 10 ml per injection. The test ed concentrations of D609 and KC12 (5 mg/ml solution) and of rh-TNF al pha (50 mu g/ml) were used for the treatment experiments. The repeated injections of the compounds to 11 sarcoid affected horses were also w ell-tolerated, except by one horse. In this case the treatment had to be interrupted after two injections because of severe reaction, i.e. f ever and lameness due to oedemas. Five horses (n = 6 sarcoids) were tr eated by local, subcutaneous injection of D609 and KC,, under the tumo ur at intervals of 3 weeks. On one periocular sarcoid the compounds we re applied as an ointment. After a follow-up period of 18 months, 5 ru mours did completely regress and one remained unchanged. The periocula r tumour showed a reduction in size. Five horses (n = 9 sarcoids) were then treated with a combination of D609, KC12 and rhT-NF alpha. After a follow-up period of 13 months, one horse showed a complete regressi on of the treated tumour, 3 horses showed an important reduction (50 % ) in size of the treated neoplasms (n = 4) and one of those also exhib ited a complete regression of the other multiple, small untreated rumo urs. Two sarcoids (2 horses) did not change and one of the horses even showed continuous growth of two other treated sarcoids. These prelimi nary results may open a new way to conservative treatment of the equin e sarcoid.