MOPP and LOPP for Canine Lymphoma: Distinct Alkylator-Rich Protocols

MOPP and LOPP multi-agent chemotherapy is covered as alkylator-rich canine lymphoma protocols, with species, evidence, regulatory, safety, interaction and monitoring boundaries for a veterinarian-led decision.

Alkylator-rich canine lymphoma protocols. MOPP contains mechlorethamine, vincristine, procarbazine and prednisone or prednisolone. LOPP replaces mechlorethamine with lomustine; the two protocols are related but not interchangeable.

MOPP contains mechlorethamine, vincristine, procarbazine and prednisone or prednisolone. LOPP replaces mechlorethamine with lomustine; the two protocols are related but not interchangeable.

Both protocols combine DNA-damaging alkylator activity, microtubule inhibition and glucocorticoid effects. LOPP uses lomustine, which adds a clinically important cumulative liver-risk profile, while MOPP uses mechlorethamine, a vesicant with distinct administration hazards.

MOPP has historical evidence as rescue treatment for resistant canine lymphoma. LOPP has been studied as first-line treatment for selected non-indolent T-cell lymphoma. A 2025 retrospective comparison addressed a defined population of previously untreated multicentric T-cell lymphoma and cannot select a protocol for an individual dog.

MOPP has historical evidence as rescue treatment for resistant canine lymphoma. LOPP has been studied as first-line treatment for selected non-indolent T-cell lymphoma. A 2025 retrospective comparison addressed a defined population of previously untreated multicentric T-cell lymphoma and cannot select a protocol for an individual dog.

Specialist multi-agent chemotherapy combining clinic and hazardous oral medicines

The evidence includes retrospective cohorts with different eras, eligibility criteria, prior treatments and endpoints. One study of resistant lymphoma and another of treatment-naive T-cell disease answer different questions. Response proportions from those cohorts must not be pooled into a universal expectation.

Both protocols can cause clinically important marrow suppression and gastrointestinal toxicity. Mechlorethamine extravasation can produce severe local injury. Lomustine can cause cumulative hepatotoxicity. Procarbazine is hazardous oral chemotherapy with interaction concerns, and vincristine adds gastrointestinal, neurologic and extravasation risks.

Previous chemotherapy, liver dysfunction, other marrow suppressants, serotonergic or sympathomimetic medicines and unreviewed supplements can alter risk. Substituting vinblastine for vincristine or changing the alkylator creates a different protocol and a different evidence base.

Neither MOPP nor LOPP is a regulator-approved veterinary combination product. Component drugs are used according to their applicable labels or under lawful extra-label veterinary prescribing. US use is governed by AMDUCA and a valid VCPR.

Multi-region specialist use; individual component availability, pharmacy handling and extra-label law vary.

Pathology, immunophenotype, stage, prior-response history, liver status and baseline blood counts should be documented. The oncologist defines laboratory timing, liver surveillance, tumour measurements and handling instructions for oral hazardous medicines and bodily waste. Fever, bleeding, severe gastrointestinal illness, jaundice or infusion-site injury needs prompt review.