Janssen Pharmaceutical has reported follow-up results from the Phase I MajesTEC-1 dose-escalation study, where its investigational antibody, teclistamab, provided durable responses in relapsed or refractory multiple myeloma patients.
A T-cell redirecting bispecific antibody, teclistamab targets cluster of differentiation 3 (CD3) and B-cell maturation antigen (BCMA), which is found at increased levels on multiple myeloma cells.
Data from a more than six-month median follow-up showed an overall response rate (ORR) of 65% with the recommended subcutaneous (SC) Phase II dose (RP2D) in a group of subjects who were heavily pre-treated with a median of five previous lines of treatment.
In the trial, 40 subjects received the RP2D, identified as 1500 µg/kg SC.
Durable responses that intensified over time were observed in the trial. About 58% of the subjects in teclistamab arm had a very good partial response (VGPR) or better and 40% had a complete response (CR) or better at the RP2D.
Furthermore, the median time to first established response was one month. The median duration of response was not met and 85% of the subjects were alive and receiving treatment after 7.1 months of median follow-up.
No dose-limiting toxicities at the RP2D were noted in the first part of the trial, with the most common adverse events at the dose being cytokine release syndrome and neutropenia.
Janssen noted that the favourable safety, efficacy, pharmacokinetics and pharmacodynamics validate the selection of the 1500ug/kg SC as the RP2D.
Janssen Research & Development Hematologic Malignancies vice-president and global head Yusri Elsayed said: “We remain committed to investigating new treatments and approaches for patients with multiple myeloma, including off-the-shelf, T-cell redirecting bispecific antibodies like teclistamab.
“The encouraging efficacy data reported at ASCO and especially the durability of the deep responses support the further investigation of teclistamab use as a monotherapy and in combination with other agents.”
According to preclinical studies, teclistamab showed an ability to kill myeloma cell lines and bone marrow-derived myeloma cells in patients who received heavy prior treatment.
This development comes after Janssen reported that Imbruvica plus venetoclax demonstrated overall survival benefits in a Phase II CAPTIVATE study in chronic lymphocytic leukaemia patients.