ASH 2021 | Phase I/II trial of ADCT-602 in B-ALL
Nitin Jain, MD, University of Texas MD Anderson Cancer Center, Houston, TX, describes preliminary results from a Phase I/II trial (NCT03698552) of ADCT-602, an antibody drug conjugate composed of an anti-CD22 antibody and a pyrrolobenzodiazepine (PBD) dimer cytotoxin, in patients with relapsed/refractory B-cell acute lymphoblastic leukemia (B-ALL). Patients were initially given ADCT-602 every 3 weeks, but weekly infusions were administered due to the pharmacokinetics of the drug. One patient so far has achieved minimal residual disease (MRD) negativity, and ongoing research will continue to assess the efficacy of ADCT-602. This interview took place at the 63rd ASH Annual Meeting and Exposition congress in Atlanta, GA.
Transcript (edited for clarity)
At this ASH meeting, we are reporting data for the first time for ADCT-602, which is a CD22 targeting antibody drug conjugate for relapsed/refractory B-ALL. There is currently already an approved CD22 antibody drug conjugate for relapsed/refractory B-ALL, which is inotuzumab. And inotuzumab is bound to a toxin called calicheamicin, which can cause VOD. With ADCT-602, the toxin payload is different...
At this ASH meeting, we are reporting data for the first time for ADCT-602, which is a CD22 targeting antibody drug conjugate for relapsed/refractory B-ALL. There is currently already an approved CD22 antibody drug conjugate for relapsed/refractory B-ALL, which is inotuzumab. And inotuzumab is bound to a toxin called calicheamicin, which can cause VOD. With ADCT-602, the toxin payload is different. It’s PBD, pyrrolobenzodiazepine, which does not have VOD signal in the studies which have been recorded so far.
We designed the study at MD Anderson, and now we have one other site open as well. We have treated adult patients with relapsed/refractory B-ALL with this regimen. It’s a Phase I dose-escalation study, where initially we tested every three weeks, schedule of the drug. What we realized from the PK analysis is that the drug did not last three weeks. So then we have to amend the study to make it a weekly dose level schedule. The study right now is ongoing at the weekly dose level schedule. We are in the dose escalation phase. We are starting to see some evidence of clinical activity, including one patient which we highlighted in our abstract, a patient who had failed two prior bone marrow transplants, a patient who had failed a CAR T-cell therapy, many other chemotherapy regimens, and the patient has now achieved MRD-negative remission, ongoing remission, six months plus on therapy.
Overall, the study continues to accrue. We hope to finish the Phase I part in the next six months to one year. And then depending on that, a Phase II part will begin.
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