Bispecific Antibodies Clinical Trials

**Conclusion**: Since 2024, the evidence base for bispecific antibodies (BsAbs) in relapsed/refractory multiple myeloma (RRMM) has matured with long-term follow-up from pivotal trials, new pooled safety analyses, and expanded regulatory approvals, while the approved indication remains for triple-class-exposed patients who have received ≥4 prior lines of therapy. --- ## Clinical Evidence & Efficacy ### Long-Term Follow-Up of Pivotal Trials **Ciltacabtagene autoleucel (cilta-cel)** — CARTITUDE-1 (Phase 1b/2) - **Long-term (≥5 year) data** presented at ASCO 2025 demonstrated sustained remissions and survival in patients with RRMM [1]. - Median follow-up now exceeds 5 years, confirming durable disease control in this heavily pretreated population. **Teclistamab** — MajesTEC-1 (Phase 1/2) - At a median follow-up of 22 months, 43% of patients achieved a complete response (CR) or better, with median duration of response (DOR) and median progression-free survival (PFS) of 24 months and 12.5 months, respectively [6]. - Patients with extramedullary disease (EMD), high tumor burden (bone marrow plasmacytosis >60%), and prior BCMA-directed therapy had lower response rates [6]. **Elranatamab** — MagnetisMM-3 (Phase 2) - In BCMA-directed therapy-naïve patients (n=123), ORR was 61% (95% CI 52–70) at a median follow-up of 14.7 months [5][6]. - Median PFS: 17.2 months (95% CI 9.8–NE); median OS: 21.9 months [5][6]. - Lower response rates observed in patients with EMD, high-risk cytogenetics, and R-ISS stage III disease [5]. ### Real-World Evidence Real-world studies of teclistamab have reported comparable efficacy, with ORR ranging from 60% to 62%, albeit with shorter follow-up [6]. ### Efficacy in Special Populations: Renal Impairment A multicenter retrospective analysis evaluated teclistamab in patients with RRMM and renal impairment (RI), a population excluded from the pivotal MajesTEC-1 trial (which required CrCl ≥40 mL/min) [3]. This analysis provides the first evidence of teclistamab's efficacy and safety in patients with moderate-to-severe RI, addressing a critical evidence gap [3]. --- ## Safety Profile ### Pooled Analysis of BsAbs in MM (2025) A comprehensive pooled analysis of 22 trials involving 2,374 patients with MM (through April 2025) provided updated safety benchmarks [4]: | Adverse Event | All-Grade (%) | Grade 3/4 (%) | |---------------|---------------|---------------| | Infections | 45.8 | 20.3 | | Neutropenia | 40.4 | 35.2 | | Anemia | 39.2 | 24.5 | | Thrombocytopenia | 21.4 | 13.5 | | Lymphopenia | 19.2 | 17.7 | | Cytokine Release Syndrome (CRS) | 65.0 | 1.5 | **Key comparative findings**: - CRS and need for tocilizumab were significantly less frequent with BCMA-targeted BsAbs vs GPRC5D/FcRH5-targeted BsAbs (P < 0.002) [4]. - Principal component analysis (PCA) revealed similar clustering patterns for all-grade and grade 3/4 AEs across most agents, except for three outliers [4]. ### Elranatamab Safety Similar safety signals to other BCMA-targeting BsAbs have been noted, including a high incidence of hematological toxicity (>80%), CRS (58%), and infection (67%; grade 3–4 in 35%) [5]. --- ## Approved Indications | Agent | Target | Approval Date | Indication | |-------|--------|---------------|------------| | **Teclistamab** | BCMA × CD3 | October 2022 (FDA) | RRMM after ≥4 prior lines of therapy including an immunomodulatory agent, a proteasome inhibitor, and an anti-CD38 monoclonal antibody [3][6] | | **Elranatamab** | BCMA × CD3 | August 2023 (FDA, EMA) | RRMM after ≥4 prior lines of therapy including a PI, IMiD, and an anti-CD38 monoclonal antibody [5][6] | | **Talquetamab** | GPRC5D × CD3 | 2023 (FDA) | RRMM after ≥4 prior lines of therapy [6] | **No new approved indications have been added since 2024** for these agents. The approved indication remains consistent across all three: **triple-class-exposed RRMM with ≥4 prior lines of therapy**. --- ## Guideline Recommendations - **Teclistamab** is now a recommended treatment from second relapse onwards in patients with triple-class-exposed (TCE) RRMM per the **2025 European Hematology Association-European Myeloma Network (EHA-EMN) guidelines** [2]. - The **International Myeloma Working Group (IMWG) Immunotherapy Committee** has published consensus guidelines and recommendations for optimal use of T-cell-engaging BsAbs in MM, covering patient selection, adverse event management, and infection prophylaxis [5]. --- ## Emerging Data and Ongoing Research ### Combination Strategies - **Teclistamab + talquetamab** (RedirecTT-1; NCT04586426): A study evaluating the combination of these two BsAbs in RRMM [2]. - **Teclistamab + daratumumab + pomalidomide**: Results from MajesTEC-2 cohort A and TRIMM-2 studies presented at ASH 2024 [2]. - **Talquetamab + pomalidomide** (MonumenTAL-2): Phase 1b results showing safety and preliminary efficacy [6]. ### Next-Generation Agents - **JNJ-79635322 (JNJ-5322)**: A novel, next-generation trispecific antibody (TsAb) — initial Phase 1 results presented at ASCO 2025 [2]. - **ISB 2001**: A BCMA × CD38 × CD3-targeting trispecific antibody — dose escalation results from the TRIgnite-1 study presented in 2025 [2]. ### Sequencing After BCMA-Directed Therapies - Teclistamab has demonstrated efficacy in patients with prior exposure to other BCMA-targeted agents (e.g., CAR-T or other BsAbs), though response rates are lower [6]. - Salvage strategies including retreatment with BCMA-directed approaches after BCMA CAR-T relapse are being actively investigated [6]. --- ## Critical Gaps 1. **Renal impairment data**: While retrospective data are now available for teclistamab, prospective studies in patients with moderate-to-severe RI (CrCl <40 mL/min) remain highly anticipated [3][7]. 2. **Optimal sequencing**: The optimal sequence of BsAbs relative to CAR-T therapy and other immunotherapies has not been established in prospective trials. 3. **Long-term safety**: Extended follow-up beyond 5 years is needed to characterize late-onset toxicities and durability of responses. 4. **Comparative effectiveness**: No head-to-head trials directly comparing different BsAbs (e.g., teclistamab vs elranatamab) have been conducted. --- *This analysis is based on retrieved literature and clinical guidelines. All clinical decisions should be made in the context of individual patient factors and verified against the latest official prescribing information.*