Introduction

Dogs with lymphoma that fail CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) chemotherapy before completion of their protocol are commonly thought to have a poor long-term outcome; however, no previous studies have evaluated the effect of early CHOP relapse on progression free interval (PFI) or overall survival time (OST) for patients undergoing rescue chemotherapy. The aim of this study was to determine if dogs with multicentric lymphoma that fail CHOP prior to completion have a worse outcome with rescue therapy than dogs that complete CHOP.

Methods

Data were collected from six previous retrospective or prospective studies in 193 dogs with multicentric lymphoma that received CHOP-based chemotherapy then received either lomustine (CCNU), L-asparaginase and prednisone, or rabacfosadine (Tanovea-CA1) with or without prednisone or L-asparaginase.

Results

Length of CHOP PFI (progression during versus after completion of CHOP) was significantly associated with PFI and post-relapse OST for both rescue protocols. Patients achieving a complete response to CHOP had a significantly longer PFI for both rescue protocols. Immunophenotype (B vs. T cell) was not significantly associated with response, PFI or OST for L-asparaginase/lomustine but was significantly associated with PFI for rabacfosadine.

Conclusion

Dogs with multicentric lymphoma that fail a CHOP protocol prior to completion are likely to have shorter PFI and OST with rescue therapy. Immunophenotype does not significantly affect outcome with L-asparaginase/lomustine but is associated with PFI for rabacfosadine.

Funding Information

This work was supported by VetDC and Elanco (FDA grant # 1R01 FD006323-01).