Gemtuzumab ozogamicin-induced sinusoidal obstructive syndrome treated with defibrotide: a case report

Combining Biology and Chemistry for a New Take on Chemotherapy: Antibody-Drug Conjugates in Hematologic Malignancies

PURPOSE OF REVIEW

This review is about the antibody-drug conjugate (ADC), a form of drug delivery consisting of a monoclonal antibody, linker, and cytotoxic payload. We summarize the history of ADC development, highlighting the three FDA-approved ADCs currently available.

RECENT FINDINGS

Gemtuzumab ozogamicin is a CD33-targeted ADC linked to calicheamicin. It is approved for CD33+ AML in the first line or the relapsed or refractory (R/R) setting. Brentuximab vedotin is a CD30-targeted ADC bound to MMAE. It is approved for the treatment of certain R/R CD30+ lymphomas. Recently, it has been approved for first line therapy with chemotherapy in advanced HL. Inotuzumab ozogamicin is a CD22-directed ADC attached to calicheamicin indicated for the treatment of adults with R/R B cell precursor ALL. Three ADCs have been approved for the treatment of various hematologic malignancies. We discuss the pertinent human trials that led to FDA approval. We include our perspectives about drug resistance, toxicities, and future development.

Antibody-based therapy of acute myeloid leukemia with gemtuzumab ozogamicin

Antibodies have created high expectations for effective yet tolerated therapeutics in acute myeloid leukemia (AML). Hitherto the most exploited target is CD33, a myeloid differentiation antigen found on AML blasts in most patients and, perhaps, leukemic stem cells in some. Treatment efforts have focused on conjugated antibodies, particularly gemtuzumab ozogamicin (GO), an anti-CD33 antibody carrying a toxic calicheamicin-g 1 derivative that, after intracellular hydrolytic release, induces DNA strand breaks, apoptosis, and cell death. Serving as paradigm for this strategy, GO was the first anti-cancer immunoconjugate to obtain regulatory approval in the U.S. While efficacious as monotherapy in acute promyelocytic leukemia (APL), GO alone induces remissions in less than 25-35% of non-APL AML patients. However, emerging data from well controlled trials now indicate that GO improves survival for many non-APL AML patients, supporting the conclusion that CD33 is a clinically relevant target for some disease subsets. It is thus unfortunate that GO has become unavailable in many parts of the world, and the drug's usefulness should be reconsidered and selected patients granted access to this immunoconjugate.

Hepatopathy-thrombocytopenia syndrome (HTS) after actinomycin-D therapy: report of three cases and review of the literature

Hepatopathy-thrombocytopenia syndrome (HTS) is a severe complication very similar to vein occlusive disease (VOD), also known as hepatic sinusoidal obstructive syndrome (SOS), characterized by fever, hepatopathy (hepatomegaly with abnormal liver function tests), ascites, weight gain, jaundice, and thrombocytopenia (platelet count less than 25 × 10(3)/μL). It has been generally observed in patients with Wilms tumor, and is commonly associated to administration of actinomycin D. We report three children with Wilms tumor, with severe HTS/SOS, but had a different outcome, in spite of vigorous supportive therapy.

What role does gemtuzumab ozogamicin have in the treatment of acute myelogenous leukemia?

Gemtuzumab ozogamicin (GO) is a novel, targeted chemotherapy designed to treat acute myeloid leukemia (AML). GO consists of an antitumor antibiotic, calicheamicin, linked to a humanized monoclonal antibody against CD33. It has been approved in the United States since 2000 to treat CD33+ AML in first relapse in older adults who are not candidates for cytotoxic therapy. Beyond this indication, the role of GO is evolving. Single-agent GO has a limited role in de novo AML. Incorporation of GO into standard induction treatment in de novo and relapsed AML is feasible. Comparative phase III studies of such an approach are ongoing. GO is associated with serious toxicities, such as infusional reactions, transient liver function test abnormalities, and veno-occlusive disease of the liver, especially in patients who undergo hematopoietic stem cell transplantation.