For patients living with Relapsed or Refractory Multiple Myeloma (RRMM), life revolves around treatment cycles, clinical trials, brief periods of good health, and the uncertainty of when they will be sick again. By definition, RRMM is a rare type of incurable blood cancer referred to as relapsed when the cancer returns within 60 days of last treatment, or refractory, when treatment stops working altogether. For the roughly 160,000 people living with this disease, new hope is found in Pfizer’s Elrexfio™ drug, which has received accelerated approval from the U.S. Food and Drug Administration (FDA).
“Elrexfio reflects our ongoing commitment to developing scientific breakthroughs that meaningfully improve outcomes for people with cancer. Discovered at Pfizer, we advanced this therapy from a first-in-patient trial to approval in less than five years, because we know that time is life for people living with multiple myeloma.” Pfizer’s Chief Commercial Officer and President of Global Biopharmaceuticals Business, Angela Hwang, highlights the importance of the FDA’s decision to grant Pfizer access to the Accelerated Approval program, which provides early approval for pharmaceuticals targeting serious medical conditions and filling an unmet medical need.
Elratnamab-bcmm, branded as Elrexfio, is designed to treat adults with RRMM. Elrexfio leverages a bispecific T-cell engager (BiTE) as a form of targeted therapy, with response rate results expressed in patients who have undergone several cancer treatments, including a proteasome inhibitor, an anti-CD38 monoclonal antibody, and an immunomodulatory agent. The drug works by binding to the CD3 protein on healthy T cells (the immunity cells responsible for eliminating cancer) and the BCMA protein on myeloma cells. By bringing the T cells closer to the cancer cells, the T cells can more effectively kill the myeloma.
The accelerated approval of Elrexfio was based on results obtained from the single-arm Phase 2 MagnestisMM-3 trial, and the FDA has expressed that conditions for continued approval are contingent on confirmatory trials.
Benefits of Elrexfio
Pfizer has reported encouraging data indications from the MagentisMM-3 trial. RRMM patients have shown partial or complete responses to the drug, a significant breakthrough for patients who have stopped responding to existing myeloma treatments. RRMM patients experience a high treatment and symptom burden, and are often forced to plan their lives around intensive treatment schedules—and usually with a low degree of long-term tolerability. One of the key considerations in the development of Elrexfio was the patient experience and how this can be improved.
In seeking to treat RRMM more like a chronic illness rather than a terminal one, Pfizer has created a drug that is convenient and effective. Elrexfio is a monotherapy administered by injection; this reduces the clinical time for patients and vastly improves quality of life. The administration schedule is also vastly improved, with patients receiving a weekly dose for six months, after which they receive the injection every second week. This is a first of its kind BCMA treatment in the U.S. for patients who previously had to travel to specialist oncologists for treatments ranging from 2 to 8 hours long; this ready-to-use injection is revolutionary.
The positive clinical results from Phase 2 that led to the accelerated approval indicated an objective response rate of 57% in cohort A (patients that received at least four lines of therapy).
Of these, 82% maintained a response for a minimum of nine months, and on average, patients started showing their first signs of response within 36 days. The clinicians are invested in ensuring this response rate improves significantly, and learning around the other 43% will be important in any iterative development of the drug.
Cohort B consisted of 64 patients, who had each received the prescribed four prior lines of therapy, which included a BCMA-directed treatment (a similar treatment to Elrexfio). For Cohort B, the overall response rate was 33%. Using 10 months as a median time period, the trial indicates an estimated 84% maintained the response for a minimum of nine months. Pfizer also released longer-term efficacy data at the 2023 European Hematology Association meeting, which took results from a median follow-up at 14.7 months. Cohort A achieved an objective response rate of 61%; however, results for overall survival, progression-free survival, and median duration of response had not yet been achieved. The lack of a median duration of response is a strong indication that Elrexfio has long-term durability, ensuring patients can use this drug for an extended period of time before going into relapse or refraction.
Elrexfio vs Tecvayli™
For RRMM patients, it’s a relief to know that pharmaceutical companies invest in finding a viable treatment path for this cancer. Tecvayli (teclistamab-cqyv) and Talvey™ (talquetamab-tgvs) are two other treatment options offered by J&J, available through clinical trials. Talvey targets the GPR5CD protein, while Tecvayli is a similar treatment program to Elrexfio, working on binding to CD3 and BCMA proteins. This makes Tecvayli a direct competitor to Elrexfio. Tecvayli has also received FDA approval and is also currently in the clinical trial stage. The major difference between Tecvayli and Elrexfio is the dosage. Both of J&J’s products are dosed according to the patient’s weight, while Elrexfio has a fixed single dose.
The symptoms associated with treatment remain more or less the same between both Elrexfio and Tecvayli, with the main concern being cytokine release syndrome (CRS). Approximately 58% of patients in the Pfizer trial developed CRS, and similar concerns for Tecvayli. The other common symptoms and reactions noted were anemia and neutropenia (loss of white blood cells), which leaves patients vulnerable to infection. Fewer than 30% of patients reported additional symptoms like decreased appetite, rash, and joint pain.
One of the ways the FDA is helping Pfizer and J&J mitigate CRS is through “step-up” dosing and observation. For Elrexfio, patients are required to remain under observation after their initial dose for 48 hours and 24 hours after the second dose. In the case of Tecvayli and Talvey, patients are required to remain under observation for 48 hours after their first and second doses.
The overall benefit of the race to find an ideal treatment path is that patients have increased access to clinical trials, their clinical time for treatment is reduced, and they experience increased treatment tolerability in the long-term. Thanks to Talvey, patients will also have an additional option for treatment should they relapse after exploring either Elrexfio or Tecvayli, as it targets the GDPR5CD protein. For patients with RRMM, access to treatment is the difference between life and death. At the same time, pharmaceutical companies have the opportunity to save thousands of lives and claim their market share in an industry worth approximately $4 billion.
Conclusion
Ajay Nooka, Director of the Multiple Myeloma Program at Winship Cancer Institute of Emory University, outlined the significance of Elrexfio by highlighting the struggles patients and clinicians face. Multiple myeloma is incurable, and eventually, treatments either stop working or patients relapse. What physicians and patients need is more options, and with the increased investment from leading pharmaceutical companies into new treatment pathways, they’ve made this possible.
Heavily pretreated patients face an increased symptom burden, alongside declining survival rates with each line of therapy. Pfizer has taken the lifestyle elements of the patient experience seriously, created a drug that is easily administered and durable for long-term use, and implemented the FDA safety guidelines to ensure minimal risk of developing CRS. In short, Elrexfio represents new hope for pre-treated multiple myeloma patients and with accelerated approval, commercial access is soon to follow.
