Arcellx is already planning to investigate its CAR-T asset CART-ddBCMA in second- and third-line relapsed or refractory multiple myeloma in a randomised Phase III study, CMO Christopher Heery says. Now, the company is gearing to initiate the registrational Phase II iMMagine-1 study (NCT05396885) investigating the candidate in later-line patients: fourth-line and beyond.
While the company has previously indicated it is looking to investigate the asset in earlier line populations via an iMMagine-2 trial, Heery tells Clinical Trials Arena the Phase III is expected to enrol around 400 patients after the enrolment for iMMagine-1 is completed. The trial design will probably not be “terribly dissimilar” from ones seen with Bristol-Myers Squibb’s Abecma (idecabtagene vicleucel) and Johnson & Johnson’s Carvykti (ciltacabtagene autoleucel), he says.
CAR-T approaches Abecma and Carvykti garnered FDA approval in multiple myeloma in patients who have received four or more prior lines of therapy, in March 2021 and February 2022, respectively. Both assets are currently being investigated in earlier settings.
Abecma’s Phase III KarMMa-3 trial (NCT03651128) is enrolling 381 patients who have received at least two but no greater than four prior regimens. The study, which recruited its first patient in April 2019, has data expected sometime between 2023 and 2024, according to an April 2022 presentation.
Meanwhile, the 419-subject Phase III CARTITUDE-4 trial (NCT04181827) investigating Carvykti is recruiting patients who have previously received one to three prior lines of therapy. The first patient was enrolled in June 2020, with data expected in December 2026, according to a March 2022 EMA report. Both trials are measuring progression-free survival (PFS) as the primary endpoint.
The FDA has been very clear in discussions that it expects a randomised trial in the second- and third-line settings, because there’s a great amount of variability in patient outcomes, Heery adds. CART-ddBCMA is a cell therapy product that targets cancer cells expressing B-cell maturation antigen (BCMA), a target antigen for multiple myeloma.
Later-line multiple myeloma trial yet to start
As for Arcellx’s later-line iMMagine-1 trial, the company is working towards getting the study open and start recruiting by YE 2022, Heery says. Currently, the company is finalising the product’s technology transfer from an early research facility to a commercial launch facility, where trial participants will be dosed, he adds. iMMagine-1’s ClinicalTrials.gov listing states the trial having two sites in the US.
If iMMagine-1 delivers positive results, Arcellx expects an FDA approval sometime in 2025 in the later-line setting. The asset received FDA’s Fast Track and Orphan Drug Designations in 2020 and Regenerative Medicine Advanced Therapy Designation in 2021.
iMMagine-1’s trial design is similar to the single-arm Phase Ib/II CARTITUDE-1 trial (NCT03548207) that led to Carvykti’s FDA approval, Heery says. Data shows that in 97 patients, Carvykti delivered an overall response rate (ORR) of 97.9%, CARTITUDE-1’s primary endpoint. CARTITUDE-1 recruited participants with at least three lines of prior therapy. iMMagine-1 will enrol roughly 100 patients in the same setting, also with an ORR primary endpoint.
Update: After the publication of this article, Arcellx updated that the company will start recruiting for Phase III after the enrolment for iMMagine-1 is completed.
Cell & Gene Therapy coverage on Clinical Trials Arena is supported by Cytiva.
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