Benzinga | Dec 11, 2021 12:19PM EST

Janssen Presented Updated Results Evaluating First-in-Class Talquetamab (GPRC5DxCD3 Bispecific Antibody) in Heavily Pretreated Patients with Multiple Myeloma at ASH 2021; Said No New Safety Signals Were Identified With Longer Follow-up of Either Dose Cohort

The Janssen Pharmaceutical Companies of Johnson & Johnson announced today updated results from the MonumenTAL-1 Phase 1 first-in-human dose-escalation study of talquetamab (NCT03399799). Talquetamab is the only investigational off-the-shelf T cell redirecting bispecific antibody in clinical development targeting both GPRC5D, a novel multiple myeloma target, and CD3 on T cells.1 Results from the study show that no new safety signals were observed with longer follow-up.1 Heavily pretreated patients with multiple myeloma treated with talquetamab at the recommended subcutaneous (SC) Phase 2 doses (RP2D) administered weekly (QW) and every two weeks (Q2W) achieved high overall responses that deepened over time.1 These data were featured during the American Society of Hematology (ASH) 2021 Annual Meeting as an oral presentation (Abstract #158).1

No new safety signals were identified with longer follow-up of either dose cohort.1 The most common adverse events (AEs) at the SC 405 g/kg QW dose were cytokine release syndrome (CRS 77 percent; three percent grade 3), neutropenia (67 percent; 60 percent grade 3/4) and dysgeusia (60 percent).1 Dysgeusia was generally mild with few dose adjustments required. The most common AEs at the SC 800 g/kg Q2W dose were CRS (72 percent; all grade 1/2), neutropenia (44 percent; 36 percent grade 3/4), and dry mouth (40 percent; all grade 1/2).1 Cytopenias were mostly confined to step-up doses and cycles one and two and were reversible, including neutropenias which generally resolved within a week. Infections occurred in 33 percent of patients and there was a low rate of high-grade infections (five percent grade 3/4).1 Skin-related and nail disorder AEs occurred in 75 percent of patients, most commonly exfoliation (37 percent at SC 405 g/kg QW; 36 percent at 800 g/kg Q2W, all grade 1/2), which did not lead to treatment modification.1 Injection site reactions occurred in 16 percent of patients and were all grade 1/2.1

Pre-treatment medications (including glucocorticoid, antihistamine, and antipyretic treatments) were only required at the step-up and first full doses, and no steroid treatment was required after the first full dose.

"New treatment options are needed for patients with multiple myeloma," said Amita Krishnan, M.D., Chief, Division of Multiple Myeloma, Department of Hematology and Hematopoietic Cell Transplantation, City of Hope Comprehensive Cancer Center, Duarte, California, and principal study investigator. "The continued observation of a tolerable safety profile and durable responses seen in these updated data suggest that in both doses, talquetamab may offer a new treatment option for heavily pretreated patients."

With a median follow-up of nine months (range 0.9-17.1), 70 percent (21/30) of response-evaluable patients treated with the SC 405 g/kg QW dose achieved a response, 53 percent achieved a very good partial response (VGPR) or better, 13 percent achieved a complete response (CR) or better, and 10 percent achieved a stringent complete response (sCR).1 With a median follow-up of 4.8 months (range 0.4-11.1), 67 percent (14/21) of response-evaluable patients treated with the SC 800 g/kg Q2W dose achieved a response, 52 percent achieved a VGPR or better, 19 percent achieved a CR or better, and 10 percent achieved an sCR.1 The median duration of response (DOR) was not reached for either dose.1

Among response-evaluable patients who were triple-class refractory, a response was achieved by 65 percent (15/23) of patients treated with the SC 405 g/kg QW dose and 67 percent (12/18) of patients treated with the SC 800 g/kg Q2W dose.1 In patients who were penta-drug refractory, 83 percent (5/6) of patients responded in both dose groups.1

"These new data provide important insights into the potential safety, efficacy and tolerability of talquetamab for relapsed and refractory patients," said Sen Zhuang, M.D., Ph.D., Vice President, Clinical Research and Development, Janssen Research & Development, LLC. "We look forward to fully evaluating this novel bispecific antibody as both a monotherapy and in combination immunotherapy regimens."

The primary objectives of the MonumenTAL-1 study were to identify the recommended subcutaneous Phase 2 dose(s) (part 1) and assess the safety and tolerability of talquetamab at the recommended dose (part 2).1 As of September 2021, 102 patients with multiple myeloma who had relapsed or become refractory or intolerant to established therapies have received SC talquetamab in the study.1 For part 2, 30 patients received the weekly RP2D of SC 405 g/kg QW dosing schedule with step-up doses; 100 percent were triple-class exposed, 80 percent were penta-drug exposed, 77 percent were triple-class refractory, 20 percent were penta-drug refractory and 27 percent had prior B-cell maturation antigen (BCMA)-directed therapy.1 Twenty-five patients received the SC RP2D of 800 g/kg Q2W; 92 percent were triple-class exposed; 68 percent were pentadrug exposed; 76 percent were triple-class refractory, 24 percent were penta-drug refractory, and 16 percent had prior BCMA-directed therapy.1

Data from the Phase 2 TRiMM-2 Study Evaluating Talquetamab in Combination with DARZALEX FASPRO(r) (Abstract #161)

Additional data for talquetamab will be highlighted in an oral presentation at ASH on Saturday, December 11 (Abstract #161).2 The Phase 1b TRIMM-2 investigational study (NCT04108195) evaluated talquetamab in combination with DARZALEX FASPRO(r) (daratumumab and hyaluronidase-fihj) the CD38-directed monoclonal antibody approved to be given subcutaneously for the treatment of patients with multiple myeloma. Results suggest that the combination is tolerable in patients with relapsed or refractory multiple myeloma who had received a median of six prior lines of therapy (range 2-18), with a safety profile comparable to each agent as a monotherapy at each of three doses evaluated in the study.2

Patients received step-up doses of talquetamab of SC 400 g/kg QW (n=9); SC 400 g/kg Q2W (n=5); or SC 800 g/kg Q2W (n=15), in combination with DARZALEX FASPRO(r) at the approved dosing schedule.2 At a median follow-up of 4.2 months, 86 percent (6/7) of response-evaluable patients treated with the SC 400 g/kg QW achieved a response, and 80 percent (4/5) of patients treated with the SC 400 g/kg Q2W dose achieved a response. At the SC 800 g/kg Q2W dose of talquetamab 78 percent (7/9) of patients achieved a response.2

The safety profile of the combination appeared consistent with each agent as a monotherapy.2 At all doses, the most common AE was cytokine release syndrome (CRS), observed in 55 percent (16/29) of patients.2 All CRS events were grade 1/2 and all but one event occurred with step-up doses of talquetamab.2 CRS resolved in all patients, and no patients discontinued treatment due to CRS.2 Other AEs included dysgeusia (48 percent; all grade 1/2) and dry mouth (35 percent; all grade 1/2).2 Skin-related and nail disorders were reported in 65 percent of patients (all grade 1/2); the most commonly reported skin or nail event was skin exfoliation (28 percent, all grade 1/2).2 One patient experienced immune effector cell-associated neurotoxicity syndrome (ICANS), including one grade 3 event and one grade 1 event, both of which resolved yet resulted in discontinuation of talquetamab.2

The primary objectives of the TRiMM-2 study were to identify the Phase 2 dose (RP2D) for each component of the treatment combination (Part One); characterize the safety of the treatment combination at the RP2D (Part 2); and assess antitumor activity, pharmacokinetics and pharmacodynamics for the combination treatment (Part 3).2 Patients in the study (n=29) all had multiple myeloma and had received a minimum three prior lines of therapy or were double refractory to a proteasome inhibitor (PI) and an immunomodulatory agent; patients who had been exposed or refractory to an anti-CD38 therapy more than ninety days prior to the start of the trial were also included, as well as those refractory to anti-CD38 therapy.2

About Talquetamab

Talquetamab is a first-in-class, investigational T-cell redirecting bispecific antibody targeting both GPRC5D, a novel multiple myeloma target, and CD3, a T-cell receptor.3 CD3 is involved in activating T-cells, and GPRC5D is highly expressed on multiple myeloma cells.4,5 Results from preclinical studies in mouse models demonstrate that talquetamab induces T-cell-mediated killing of GPRC5D-expressing multiple myeloma cells through the recruitment and activation of CD3-positive T-cells and inhibits tumor formation and growth.6

Talquetamab is currently being evaluated in a Phase 1/2 clinical study for the treatment of relapsed or refractory multiple myeloma (NCT03399799) and is also being explored in combination studies (NCT04586426). In January 2021, talquetamab was granted PRIority MEdicines (PRIME) designation by the European Commission.