Efficacy and adverse events of L-Asparaginase administration as a first-line treatment for feline large-cell gastrointestinal lymphoma

Abstract

L-Asparaginase (L-Asp) is often used to induce remission in feline large-cell gastrointestinal lymphoma (LCGIL). However, no study has evaluated the efficacy and adverse events following the initial use of this drug as a first-line treatment in feline LCGIL. We retrospectively reviewed medical records of cats with LCGIL treated with L-Asp to induce remission. This study included 43 cats. The response rate (RR) after the first administration of L-Asp was 37.2% (Complete remission: 7.0%, partial remission: 30.2%). RR was significantly higher in cases with primary gastric lesions (64.3%) than in those with primary intestinal lesions (24.1%) (P=0.018), and it was also higher in cases without anemia (57.1%) than those with anemia (15.0%) (P=0.009). The most common adverse event was hyperammonemia, which occurred in 10 of 12 cases where we could compare plasma ammonia concentrations before and after the first dose of L-Asp. Plasma phosphate concentrations were also significantly increased (P<0.001) within 24 hr after the first dose. Decreased appetite, vomiting, and diarrhea were also observed in five, three, and seven cases, respectively, and Grade 3 or higher gastrointestinal signs were observed as adverse events in three cases. The median overall survival of all cats was 150 days (range, 5-1,065 days), and the median progression-free survival was 104 days (range, 2-978 days). In conclusion, L-Asp was effective to induce remission, and severe adverse events were uncommon in feline LCGIL.

Keywords: ammonia; cat; chemotherapy; phosphate; toxicity.

Fig. 1.

Comparisons of plasma ammonia (A) and phosphate (B) concentrations between before and after the first dose of L-Asparaginase. The red line shows an upper limit of reference range, and the blue line shows a lower limit. **P<0.01, ***P<0.001.

Fig. 2.

The Kaplan–Meier curve showing progression free survival (A) and overall survival (B) of the cats included in the present study. Vertical lines indicate the cases censored.

Fig. 3.

Comparisons of progression free survival (A) and overall survival (B) between the cats in Group 1 and Group 2. Vertical lines indicate the cases censored. *P=0.02.