VETINUITY
After CHOP relapse, options are re-induction with CHOP, lomustine 70-90 mg/m2 every 3 weeks, LPP, DMAC every 2 weeks, or rabacfosadine 1 mg/kg IV every 3 weeks.
Lomustine and rabacfosadine are given alone. The DMAC rows are one 14-day cycle.
Vetinuity’s lymphoma rescue table lists the options for a dog that relapses after CHOP: re-induction with the original CHOP drugs when the relapse comes well after treatment ended, single-agent lomustine at 70 to 90 mg/m2 PO every 3 weeks, the LPP combination of lomustine, procarbazine and prednisolone, DMAC on a 14-day cycle, or rabacfosadine at 1 mg/kg IV every 3 weeks for up to 5 doses. The Vetinuity lymphoma rescue dose calculator above gives milligrams for each drug. Vetinuity is the clinical assistant made by Brian Toncray, DVM, who works emergency shifts.
| Option | Doses | Cycle | Best fit |
|---|---|---|---|
| CHOP re-induction | original CHOP doses | weekly, as first line | relapse months after finishing CHOP, doxorubicin total still under the cardiac limit |
| Lomustine | 70 to 90 mg/m2 PO | every 3 weeks | oral, few visits; watch ALT |
| LPP | lomustine, procarbazine, prednisolone | 4-week cycles | relapsed high-grade lymphoma (Tanis 2018) |
| DMAC | dexamethasone 1 mg/kg PO days 1 and 8; actinomycin D 0.75 mg/m2 IV and cytarabine 300 mg/m2 day 1; melphalan 20 mg/m2 PO day 8 | 14 days | drug-resistant relapse (Alvarez 2006) |
| Rabacfosadine | 1 mg/kg IV over 30 min | every 3 weeks, up to 5 doses | relapsed B-cell lymphoma (Saba 2018) |
A dog that relapses months after a completed CHOP protocol often responds again to the same drugs. A dog that progresses while still on CHOP, or within weeks of finishing, has drug-resistant disease, and outcomes with every rescue protocol are worse (Parker 2024). Re-stage before choosing: a new staging work-up, immunophenotype if not known, and a calcium level.
CHOP (cyclophosphamide, doxorubicin, vincristine, prednisolone) is first-line for canine nodal lymphoma: median survival 302 to 321 days; prednisone alone 50 days.
Lomustine is dosed at 60-90 mg/m2 PO every 3 weeks in dogs and 50-60 mg/m2 PO every 3 to 6 weeks in cats, rounded to whole capsules, with ALT and a CBC checked before every dose.
Single-agent doxorubicin for canine lymphoma is 30 mg/m2 IV every 2 to 3 weeks for 5 doses, or 1 mg/kg in dogs under 10 kg, after a baseline echocardiogram in breeds at cardiac risk.
The WHO staging scheme describes how far canine lymphoma extends anatomically; substage a or b separately records whether systemic signs are absent or present.
COP gives cyclophosphamide 300 mg/m2 PO every 3 weeks, vincristine 0.75 mg/m2 IV weekly for 4 weeks then every 3 weeks, and daily prednisolone, in dogs and cats with lymphoma.
Yes. Dogs that progress during CHOP or soon after finishing it do worse with every rescue protocol than dogs that relapse later (Parker 2024). A late relapse is the best case for re-induction with the original drugs.
The label warns of pulmonary fibrosis, which can be fatal, and advises against use in West Highland white terriers and dogs with pulmonary fibrosis or poor lung function.
No. The goal is a second remission with good quality of life; second remissions are usually shorter than the first.
Vetinuity explains clinical options with journal citations.
The veterinarian diagnoses and prescribes.