A New Era for Multiple Myeloma Treatment: Bispecific Antibodies Enter the Fray

Step aside, CAR-Ts; with three FDA approvals, the class of bispecific antibodies has begun to take on the relapsed/refractory multiple myeloma treatment segment.

Currently, the US Food and Drug Administration (FDA) has authorized 10 bispecific antibodies and one bispecific molecule, the majority of which are approved for oncology indications, mostly hematological malignancies (mainly multiple myeloma and diffuse large B-cell lymphoma [DLBCL]). Only two bispecific antibodies, HEMLIBRA and VABYSMO, are authorized for non-oncology indications such as hemophilia A, neovascular (wet) age-related macular degeneration, and diabetic macular edema, respectively. The US FDA authorized three bispecific antibodies (VABYSMO, TECVAYLI, and LUNSUMIO) and one bispecific molecule (KIMMTRAK) in 2022.

The multiple myeloma treatment market is rapidly evolving, and current and emerging key players face the biggest risk due to this high degree of innovation. Antibody-drug conjugate (ADC), CAR-T cell treatments, and bispecific antibodies are just a few of the novel modes of action that have recently entered the market for later lines of therapy. The landscape of bispecific antibodies is anticipated to evolve in the coming years, with multiple companies entering the multiple myeloma treatment market with their product. J&J dominates the multiple myeloma treatment space by adding two bispecific antibodies approved in the field. TECVAYLI (teclistamab) became the first bispecific antibody to get the regulatory nod for treating relapsed/refractory multiple myeloma (RRMM) in 2022 in the United States and Europe. Later in 2023, TALVEY (talquetamab) and ELREXFIO (elranatamab) were approved for RRMM. 

What is new in the field of bispecific antibodies for multiple myeloma treatment in 2023?

Several multispecific antibodies under development are also making progress. Bispecific antibodies have seen significant progress for hematological oncology indications in the last few years, especially in 2022 and 2023. In August 2023, the US FDA approved four bispecific antibodies for indications like DLBCL and Multiple Myeloma. 

• On 10 August 2023, J&J received FDA approval for its second bispecific antibody TALVEY (talquetamab), for treating RRMM, who have received at least four prior lines of therapy.
• On 14 August 2023, the US FDA approved a third bispecific antibody ELREXFIO (elranatamab), for treating RRMM who have received at least four prior lines of therapy.
• On 18 August 2023, J&J received approval from the European Commission (EC) for TECVAYLI, providing the option for a reduced dosing frequency of 1.5mg/kg every two weeks in patients who have achieved a complete response (CR) or better for a minimum of six months.
• Based on the Phase II results of linvoseltamab, Regeneron Pharmaceuticals plans to submit a Biologics License Application (BLA) to the FDA in the second half of 2023 in RRMM.

What is the main target of bispecific and CAR-T cell therapies?

According to DelveInsight’s pipeline analysis of multiple myeloma, B-cell maturation antigen (BCMA) is the primary target for bispecific and CAR-T cell therapies. Most approved and investigational medicines of the above-mentioned technologies target a protein known as BCMA. With several FDA-approved therapies, BCMA has emerged as a hot target in multiple myeloma. BCMA is frequently expressed on the surface of the malignant plasma cells that characterize this cancer type, which is key to its potential in multiple myeloma therapy.

Who will win in the battle of bispecific antibodies landscape in relapsed/refractory multiple myeloma treatment?

Johnson & Johnson’s (J&J) TECVAYLI (BCMA × CD3) is the first bispecific antibody to be approved for multiple myeloma treatment. It targets BCMA, a protein that is highly expressed in myeloma cells, and CD3, a protein that is essential for T-cell activation. TECVAYLI is J&J’s fourth approved therapy for multiple myeloma treatment, adding to the company’s industry-leading oncology portfolio. TECVAYLI is a ready-to-use therapy that does not require customization for each patient. In a Phase II trial involving 110 patients who had received a median of five prior lines of therapy, TECVAYLI achieved an overall response rate (ORR) of 61.8%, with 28.2% of patients reaching a complete response (CR) or better. Pfizer’s ELREXFIO is currently a main competitor of J&J’s TECVAYLI.

Pfizer’s ELREXFIO (elranatamab) is the second BCMA × CD3 bispecific antibody approved for RRMM in 2023. ELREXFIO is similar to TECVAYLI in its mechanism of action, but it has a different structure and dosing regimen. In the Phase I/II trial involving 149 patients who had received a median of six prior lines of therapy, ELREXFIO achieved an ORR of 61%, with 19% of patients reaching a CR or better. ELREXFIO faces direct competition from TECVAYLI as well as from other bispecific antibodies in development that target BCMA and CD3, such as Linvoseltamab by Regeneron Pharmaceuticals, REGN5459 by Regeneron Pharmaceuticals, and ABBV-383 (TNB383B) by AbbVie.

So far, findings from BCMA × CD3-directed bispecific antibodies are comparable, although ELREXFIO appears to have a convenience advantage. The ability of ELREXFIO to be dosed every other week after 24 weeks of weekly therapy has given it an advantage over TECVAYLI. J&J’s TECVAYLI is currently being administered weekly throughout the maintenance period. However, J&J has filed additional data to make TECVAYLI a biweekly therapy as well.

TALVEY (GPRC5D × CD3) is another bispecific antibody from J&J’s portfolio that was approved for RRMM. It targets G protein-coupled receptor family C group 5 member D (GPRC5D), a new protein that is also highly expressed in myeloma cells, and CD3. TALVEY became J&J’s fifth novel medicine and second bispecific antibody authorized for treating multiple myeloma. In Phase I/II trial involving 184 patients who had received a median of six prior lines of therapy, TALVEY achieved an ORR of 73%, with 25% of patients reaching a CR or better. J&J is also testing a combination of TALVEY and TECVAYLI in RRMM patients. The combination showed early signs of efficacy and safety in a Phase I trial.The launch price of BCMA × CD3-directed bispecific antibodies are comparable. However, TALVEY’s per-month charge of USD 45,000 is greater than TECVAYLI’s price of USD 39,500.

Another bispecific antibody from Regeneron Pharmaceuticals is set to join the multiple myeloma foray. Regeneron’ Linvoseltamab could become the third bispecific antibody to receive FDA approval that targets BCMA and CD3. The company intends to file a BLA later this year and anticipates approval by 2024. In a Phase II trial involving 121 patients who had received a median of five prior lines of therapy, linvoseltamab achieved an ORR of 64% in the 200 mg dose group and 50% in the 50 mg dose group. REGN5459 is another bispecific antibody by Regeneron Pharmaceuticals that targets BCMA and CD3. It is still in Phase I/II development and has shown impressive results in efficacy and safety. In a study involving 43 patients who had received a median of seven prior lines of therapy, REGN5459 achieved an ORR of 65.1%, with 61.9% of patients reaching a CR or better among the 21 patients treated at the higher doses (480 mg and 900 mg). However, the primary completion date of the trial is by November 2025, and Regeneron Pharmaceuticals seems to focus more on linvoseltamab.

ABBV-383 (TNB383B) is another bispecific antibody that targets BCMA and CD3. AbbVie is developing it in collaboration with Teneobio. It is still in Phase I/II development and has shown promising results in efficacy and safety. In a study involving 70 patients who had received a median of five prior lines of therapy, ABBV-383 achieved an ORR of 79%, with 34% of patients reaching a CR or better. Cevostamab is a different bispecific antibody that targets FcRH5, a protein related to BCMA but has a lower expression on normal B cells and CD3. It is being developed by Roche, and it is still in Phase I/II development. It has shown modest results in terms of efficacy and safety. In a study involving 60 patients who had received a median of five prior lines of therapy, cevostamab achieved an ORR of 46.7%, with 13.3% of patients reaching a CR or better. Cevostamab has the lowest ORR among all the bispecific antibodies, and Roche has not announced any anticipated BLA filing plans for this multiple myeloma therapy.

Companies are trying to get to early lines of treatment settings now that bispecific antibodies have been approved by the FDA in later lines. However, it is too early to predict patient outcomes and performance. The bispecific antibody market is projected to grow overcrowded as a result of many approvals and intensive pipeline activity. The competition between drugs with similar targets will be fierce. For example, there are many BCMA-targeting drugs on the market, two CAR-T cell therapies and two bispecific antibodies, and some are expected to receive regulatory approval by next year in a later line. Moving into early lines of setup would be the ideal plan for pharma key players. J&J and Pfizer are working extensively to broaden the label of their respective bispecific antibodies since both companies are conducting clinical trials in an array of settings with and without combination.

Are bispecific antibodies better than CAR-Ts?

Both CAR T-cell therapy and bispecific treatment are gaining popularity. Both drugs have induced profound and long-lasting responses in R/R patients, which has never been seen previously. The question is, which is better for patients, CAR T-cell therapy or bispecific therapy? Both therapies have advantages and disadvantages. CAR T-cell therapy is a “one-and-done” therapy, whereas bispecific therapies are not. Bispecific antibodies require ongoing treatment. CAR-T therapies have shown remarkable efficacy in multiple myeloma, but they also have some drawbacks, such as the risk of cytokine release syndrome (CRS), a potentially life-threatening inflammatory reaction. CRS can also occur with bispecific antibodies but is usually less severe than CAR-T therapies.

Regarding safety, none of the bispecific antibodies exhibit unusual neurotoxicity, which is a major advantage for bispecific antibodies over CAR-T cell therapies for multiple myeloma. In terms of safety, bispecific antibodies are a clear winner, and owing to the high-grade CRS, high-grade neurotoxicity, and Grade 3 or higher of BCMA-directed CAR T-cell therapies, bispecific antibodies are likely to be preferred by oncology experts. Another challenge for CAR-T therapies is the cost, convenience, and time required to produce them, as each patient needs a personalized product. Bispecific antibodies, on the other hand, are ready-made (off-the-shelf) and can be administered more easily, which is a major advantage. Another key issue with CAR-T is market access. The cost and access aspects are where bispecific antibodies can truly make a difference. Bispecific antibodies may also be more suitable for older patients or those with other health problems who cannot receive CAR-T therapies. Like CAR-T cell therapies, bispecific antibodies are increasingly making their way to the front lines.

It may be possible to combine CAR-T therapies and bispecific antibodies to target different proteins in myeloma cells and achieve a cure for this disease.

Summary

To summarize, bispecific antibodies are emerging as a new class of therapies, and J&J is leading the multiple myeloma treatment market with two approved bispecific antibodies, TECVAYLI and TALVEY, which target BCMA and CD3, and GPRC5D and CD3, respectively. Pfizer has also entered the multiple myeloma treatment market with ELREXFIO, another bispecific antibody that targets BCMA and CD3. J&J has better experience and a competitive advantage in the multiple myeloma treatment space. DARZALEX from J&J is the top CD38 antibody with regulatory approval across all therapy lines. To cut a long story short, following the success of monoclonal antibodies and CAR-T, many researchers believe bispecific antibodies can change the treatment landscape of multiple myeloma and will represent a new dimension of precision treatment.