Multiple myeloma (MM) is the second most common haematologic cancer globally. The conventional approach to managing MM involves utilising immunomodulatory agents, proteasome inhibitors, and anti-CD38 antibodies. However, the options for patients who experience disease progression despite receiving these treatments are restricted, and the overall prognosis is generally poor. Janssen’s talquetamab is a bispecific T-cell engager (BiTE), targeting GPRC5D and CD3, that is being investigated for relapsed/refractory multiple myeloma (R/R MM).

At the European Hematology Association (EHA) conference on 8-11 June 2023, results were presented from the pivotal Phase II Monumental-1 single-arm, open-label study investigating talquetamab in adults with R/R MM who had received three or more prior lines of therapy. The patients received subcutaneous talquetamab at the recommended Phase II doses of 0.8mg/kg biweekly (Q2W) or 0.4mg/kg weekly (QW) with step-up doses. Notably, the overall response rate to talquetamab was found to be similar across both dosage regimens. Among the response-evaluable patients treated with the 0.4mg/kg QW dose, 74.1% achieved a positive response, with 59.4% achieving a very good partial response or better, 9.8% achieving a complete response, and 23.8% achieving a stringent complete response. The 12-month overall survival rates varied between the different cohorts, with 77.4% for the 0.8mg/kg Q2W dose, 76.4% for the 0.4mg/kg QW dose, and 62.9% for the prior T-cell redirection cohort. Importantly, the study demonstrated a low discontinuation rate of 8% in the 0.8mg/kg Q2W cohort and 5% in the 0.4mg/kg QW cohort due to adverse events, and no new safety concerns were observed during the longer-term follow-up period.

Talquetamab offers a distinct competitive advantage with its innovative mode of action, enabling the treatment of patients resistant to anti-B cell maturation antigen (BCMA) therapeutics. While other competitors are conveniently administered via a subcutaneous route, talquetamab, administered intravenously, may become the agent of choice in later lines of therapy when other options are exhausted. Chimeric antigen receptor T cell (CAR-T) therapies are also gaining traction in the MM pipeline, which could be a potential threat; however, BiTEs, including talquetamab, offer speed and convenience, as they are “off-the-shelf” products, while autologous CAR-Ts need to be sent to an offsite manufacturing centre and typically require two weeks production time. As a first-in-class GPRC5D-targeting BiTE, Janssen’s talquetamab is set to have an advantage in the MM market, with GlobalData estimating it could launch as early as 2024 in the US.