Second-line therapeutic efficacy of ZACTRAN® (gamithromycin injectable solution) against Swine Respiratory Disease in a field trial in Japan

Swine Respiratory Disease (SRD) is a complex condition involving viral agents and bacterial agents such as A. pleuropneumoniae , H. parasuis and P. multocida. These organisms often act together to increase the severity and duration of the disease, therefore, appropriate control of these pathogens is important for swine health management. The present abstract refers to the field efficacy of ZACTRAN®, Merial in comparison with ADVOCIN® (Danofloxacin mesylate injectable solution), Zeotis when used as a second-line therapy for the treatment of SRD in pigs that had failed to respond to first line therapy.

The study was conducted on 2 Japanese farms. Each site was recruited based on the confirmation of SRD clinical signs associated with lesions and isolation of the target pathogens in lung tissue at necropsy from 5 sentinel pigs per site.

A total of 63 3 month-old pigs weighing 21.5 to 43 kg were recruited on Day 0 (D0). The included pigs were from the same batch on each test site. These pigs displayed a minimum level of a composite SRD clinical score for respiratory condition, cough, physical activity and appetite and a body temperature of at least 39.5°C on D-7, D-5/D-4 and on D0 just prior to treatment allocation. They has failed to respond to treatment with either an amoxicillin therapy (15 mg/kg bodyweight (BW), on D-7 and D-5) or oxytetracycline (20 mg/kg BW, on D-7 and D-4).

Allocation to the treatment groups was performed randomly in replicates of 3 pigs in a 2:1 ratio of ZACTRAN-treated pigs to ADVOCIN-treated pigs. On D0, ZACTRAN was administered IM at 6.0 mg/kg BW once; ADVOCIN was injected once daily for 3 consecutive days IM at 1.25 mg/kg BW.

Pigs were monitored daily for their clinical scores until D14. A clinical improvement index was calculated for each pig using the clinical scores recorded on D0 and D7. The proportion of improved pigs for each treatment was compared using a non-inferiority hypothesis test (non-inf. margin = 0.15).

No health abnormality other than SRD related symptoms was observed in any pigs treated with ZACTRAN. No local reactions were observed in any ZACTRAN-treated pigs. The proportion of improved pigs was 86% in ZACTRAN-single-treated pigs and 65% in ADVOCIN-three-time-treated pigs. This result supported that on single injection of ZACTRAN was equivalent to or better than three consecutive injections of ADVOCIN, a reference product approved for the treatment of SRD.

Under the conditions of this trial, a single IM injection of ZACTRAN was shown to be effective for the second-line treatment of pigs with spontaneously acquired SRD that had failed to respond to first line treatment by providing clinical cure of 86%.

Disclosure of Interest: Y. Kondo Conflict with: Merial Japan Limited, N. Nakanishi: None Declared, Y. Wakui Conflict with: Merial Japan Limited, A. RichardMazet Conflict with: Merial S.A.S., K. Tokuyama Conflict with: Merial Japan Limited, G. Kinoshita Conflict with: Merial Japan Limited, P. Jeannin Conflict with: Merial S.A.S.