Zamyl (lintuzumab)

While previous CD33-targeting antibody-drug conjugates (ADCs) like gemtuzumab ozogamicin (GO, Mylotarg) have shown efficacy in AML treatment, they have suffered from toxicity and narrow therapeutic window...The development of GLK-33 addresses the limitations of previous ADCs, offering a wider therapeutic window, improved tolerability, and activity against drug-resistant leukemia cells. These findings encourage further exploration of GLK-33 in AML through clinical trials.

CD33 is a preferential target for AML CAR T cell therapy as it is expressed on the majority (>80%) of AML blasts and because prior clinical experience with gemtuzumab ozogamicin (GO; tradename: MylotargTM) has demonstrated the safety and efficacy of targeting CD33...Patients will receive lymphodepletion on days -5 to -2 with fludarabine (total 120 mg/m2) and cyclophosphamide (total 1000 mg/m2) followed by infusion of VCAR33 on Day 0...*NCT number pending. Clinical trial information submitted to CT.gov on July 19, 2023.

CD33 is widely expressed by myeloid cells and is a validated drug target in acute myeloid leukemia (AML), as shown by the benefit of some patients from the CD33 antibody-drug conjugate gemtuzumab ozogamicin (GO)...In summary, our findings demonstrate that BMS-986357 TriNKET® has potent CD33-dependent cytolytic activity in vitro against human AML cells, supporting the drug's exploration in early phase clinical trials. One such trial (NCT04789655) has opened accrual for adults with relapsed/refractory AML.

CD33-M2T has demonstrated clear advantages over anti-CD33 monoclonal antibodies (e. g. , gemtuzumab, lintuzumab), including the ability to bind to the truncated alternatively spliced version of CD33, long duration of action, and no overt toxicities in mice. Conclusions These experiments demonstrate the preclinical potential of an innovative immunotherapy targeting CD33-positive childhood AML.

In this study, we demonstrate CD33 ARC alpha targeted radiotherapy depletes human CD33 positive immune suppressing MDSCs present in multiple cancer types, to enhance antitumor immunity. These findings present a translatable strategy that supports further evaluation of 225Ac lintuzumab as a MDSC targeting agent to improve the efficacy of antitumor therapies.

An I-labeled CD45 antibody (Iomab-B [apamistamab-I131]) is currently studied in the registration-type phase 3 SIERRA trial (NCT02665065) for this purpose...Clinical efforts with At-labeled CD45 antibodies and Ac-labeled CD33 antibodies (e.g. Ac-lintuzumab [Actimab-A]) are ongoing. A first anti-AML RIT may soon become available. This might propel further work to develop RIT-based treatments for AML, with many such efforts already ongoing.

CD33 is a critical antigen for potential immunotherapeutic targeting in patients with AML. Based on this rigorous preclinical evaluation, our validated clinical grade lintuzumab-CD28/CD3ζ CD33CART immunotherapy is now under evaluation in a first-in-child/first-in-human phase 1 clinical trial for children and adolescents/young adults with relapsed/refractory AML.

There results suggest that the combination of Ac-lintuzumab with venetoclax is a promising therapeutic strategy for the treatment of patients with venetoclax-resistant AML. Clinical trial of this combination therapy (NCT03867682) is currently ongoing.