Polaris Rx Selected by Bristol Myers Squibb to Dispense First-in-Class Multiple Myeloma Therapy ZENBEXUS (Iberdomide)
Polaris Rx has announced that it has been selected by Bristol Myers Squibb (BMS) to dispense ZENBEXUS™ (iberdomide), the first cereblon E3 ligase modulator (CELMoD) therapy approved by the U.S. Food and Drug Administration (FDA). The selection represents an important development in expanding patient access to an innovative treatment option for adults living with multiple myeloma, particularly those whose disease has returned or stopped responding to previous therapies.
ZENBEXUS received FDA approval in combination with daratumumab and hyaluronidase-fihj and dexamethasone for the treatment of adults with multiple myeloma who have received at least one prior line of therapy, including both a proteasome inhibitor and an immunomodulatory agent.
Through its selection by Bristol Myers Squibb, Polaris Rx will play a role in dispensing the newly approved therapy and supporting patients throughout their treatment journey. The company’s pharmacy services are expected to provide patients and healthcare professionals with additional assistance in managing treatment, coordinating medication access, and maintaining adherence to prescribed therapy.
The introduction of ZENBEXUS represents an important advancement in multiple myeloma treatment because it belongs to a new class of medicines known as cereblon-modulating protein degraders. These therapies are designed to influence the degradation of specific proteins involved in cancer cell survival and proliferation, offering a different therapeutic approach from conventional treatment strategies.
The FDA granted accelerated approval to ZENBEXUS on August 13, 2026, based on findings from the Phase 3 EXCALIBER-RRMM clinical trial. The study demonstrated encouraging results, with 41% of patients receiving the ZENBEXUS-based combination achieving a complete response with minimal residual disease (MRD) negativity.
The approval also marks the first time the FDA has approved a new multiple myeloma drug based directly on MRD findings, highlighting the growing importance of deeper disease response measurements in evaluating cancer treatments.
Polaris Rx to Support Access to First-in-Class CELMoD Therapy
Polaris Rx’s selection by Bristol Myers Squibb positions the pharmacy among a select group of dispensing partners responsible for extending access to ZENBEXUS. The partnership is expected to support the distribution of the therapy to eligible patients and provide additional pharmacy-based assistance during treatment.
For patients with multiple myeloma, access to newly approved therapies can involve several considerations, including prescription coordination, medication availability, treatment education, and ongoing communication with healthcare providers.
As ZENBEXUS is an oral medication taken at home, patients may benefit from pharmacy support that helps them understand their prescribed treatment and maintain consistency throughout their therapy.
Eric Sredzinski, PharmD, Chief Strategy Officer of Polaris Rx, emphasized the importance of the company’s selection and its commitment to supporting patients receiving the new treatment.
“Polaris Rx is proud to be among a select group of pharmacies extending access to ZENBEXUS, the first therapy of its kind for patients with relapsed multiple myeloma,” said Sredzinski.
He noted that because ZENBEXUS is administered at home, pharmacists and patient-support teams can help individuals remain on track with their treatment between scheduled clinical visits.
“We’re excited to help bring this new option to patients and the care teams who support them,” he added.
The company’s role highlights the importance of specialty pharmacy services in the delivery of advanced oncology medicines. Specialty pharmacies often provide additional support for patients receiving complex treatments, including medication education, prescription coordination, and assistance with ongoing treatment management.
For individuals living with relapsed multiple myeloma, maintaining access to prescribed medications and receiving appropriate support can be important components of long-term disease management.
Multiple Myeloma Continues to Represent a Significant Healthcare Challenge
Multiple myeloma is a blood cancer that develops from plasma cells, a type of white blood cell found primarily in the bone marrow. Healthy plasma cells play an important role in the immune system by producing antibodies that help the body fight infections.
In multiple myeloma, abnormal plasma cells grow uncontrollably and accumulate in the bone marrow. These malignant cells can interfere with normal blood cell production and contribute to several disease-related complications, including bone damage, anemia, kidney problems, and an increased risk of infections.
The disease is generally considered incurable, although advances in treatment have significantly expanded the therapeutic options available to patients and improved disease management.
According to estimates from the American Cancer Society, approximately 36,000 people in the United States are expected to be diagnosed with multiple myeloma in 2026, while approximately 10,850 deaths are projected during the same year.
Multiple myeloma is more commonly diagnosed in older adults, with most patients aged 65 years or older at diagnosis. The average age at diagnosis is approximately 69 years.
Although treatment advances have improved outcomes, many patients eventually experience relapse or develop resistance to previously administered therapies. As the disease progresses, physicians may need to consider alternative treatment combinations that target different biological pathways.
Relapsed or refractory multiple myeloma remains a major area of unmet medical need, particularly among patients who have already received multiple classes of treatment.
The availability of therapies with different mechanisms of action is therefore important for expanding treatment possibilities and addressing disease progression following earlier interventions.
ZENBEXUS introduces a new therapeutic class into this evolving treatment landscape.
ZENBEXUS Introduces a New Class of Cereblon-Modulating Protein Degraders
ZENBEXUS (iberdomide) is the first FDA-approved therapy belonging to the cereblon E3 ligase modulator (CELMoD) class of medicines.
CELMoD therapies are designed to modify the activity of the cereblon protein, which is part of the cellular ubiquitin-proteasome system responsible for identifying and degrading specific proteins.
Protein degradation is an important biological process through which cells regulate the levels of proteins involved in growth, survival, and other essential cellular functions.
In multiple myeloma, certain proteins contribute to the survival and proliferation of malignant plasma cells. By modulating cereblon activity, CELMoD therapies are designed to promote the degradation of selected proteins involved in cancer cell biology.
This mechanism provides a distinct approach to targeting multiple myeloma compared with traditional chemotherapy and other established treatment classes.
The approval of iberdomide represents an important milestone in the development of targeted protein degradation as a therapeutic strategy for hematologic malignancies.
ZENBEXUS is available in two tablet strengths: 0.75 mg and 1 mg.
Its approved treatment regimen combines iberdomide with daratumumab and hyaluronidase-fihj and dexamethasone.
The combination brings together different therapeutic mechanisms intended to target malignant plasma cells.
Daratumumab is a monoclonal antibody directed against CD38, a protein expressed on the surface of multiple myeloma cells. It helps eliminate malignant cells through immune-mediated mechanisms.
Hyaluronidase-fihj is included in the formulation to facilitate subcutaneous administration of daratumumab.
Dexamethasone is a corticosteroid commonly incorporated into multiple myeloma treatment regimens because of its activity against malignant plasma cells and its ability to complement other anticancer agents.
By combining iberdomide with these established treatment components, the ZENBEXUS regimen is designed to provide a multi-mechanistic approach to disease management.
FDA Accelerated Approval Supported by Phase 3 EXCALIBER-RRMM Trial
The FDA granted accelerated approval to ZENBEXUS on August 13, 2026, based on clinical evidence from the Phase 3 EXCALIBER-RRMM study.
The clinical trial evaluated the ZENBEXUS-based combination against a comparator regimen consisting of daratumumab, bortezomib, and dexamethasone.
A total of 420 patients participated in the study.
Of these participants, 207 received the ZENBEXUS combination, while 213 received the comparator treatment.
The study generated encouraging findings regarding the depth of response achieved with the investigational treatment combination.
According to the reported results, 41% of patients receiving the ZENBEXUS regimen achieved a complete response with minimal residual disease negativity.
A complete response indicates that the available clinical assessments show no detectable signs of active disease according to established response criteria. However, even when patients achieve a complete response, small numbers of cancer cells may remain below the detection limits of conventional testing.
Minimal residual disease testing uses more sensitive techniques to identify very small amounts of remaining cancer cells.
An MRD-negative result means that malignant cells were not detected at the sensitivity level of the test used. This is considered an important measure of treatment depth in multiple myeloma because deeper responses may be associated with improved disease control.
The finding that 41% of patients receiving the ZENBEXUS combination achieved MRD-negative complete responses highlights the treatment’s potential to produce deep responses in patients with previously treated multiple myeloma.
The FDA’s decision also represents a notable regulatory milestone because ZENBEXUS became the first new multiple myeloma drug approved directly based on MRD findings.
Accelerated approval is intended to facilitate earlier access to therapies addressing serious diseases when preliminary clinical evidence supports a potential meaningful benefit. Continued approval may depend on verification and description of clinical benefit through confirmatory trials.
Therefore, additional clinical evidence will remain important for establishing the long-term benefit and overall role of the ZENBEXUS combination in multiple myeloma treatment.
MRD Testing Becomes Increasingly Important in Multiple Myeloma Treatment
The use of minimal residual disease testing has become an important development in multiple myeloma research and clinical practice.
Traditional response assessments generally evaluate factors such as monoclonal protein levels, bone marrow findings, and other indicators of disease activity. However, these approaches may not identify very small populations of remaining malignant plasma cells.
MRD testing provides a more sensitive method of evaluating treatment response by detecting cancer cells at levels that may not be identified through conventional assessments.
Achieving MRD negativity is increasingly considered an important measure of treatment effectiveness, particularly in clinical trials investigating therapies designed to produce deeper and more durable responses.
The EXCALIBER-RRMM findings demonstrate the relevance of this approach in evaluating the ZENBEXUS combination.
The FDA’s acceptance of MRD-based evidence also reflects the evolving approach to assessing treatment outcomes in multiple myeloma drug development.
For patients, achieving deeper disease responses may represent an important treatment objective. Nevertheless, MRD negativity does not necessarily indicate that the disease has been permanently eliminated, and continued monitoring remains necessary.
Further clinical evaluation will help determine the relationship between MRD-negative responses, response durability, progression-free survival, and long-term patient outcomes.
Specialty Pharmacy Support Plays an Important Role in Oncology Treatment
Polaris Rx’s selection as a dispensing pharmacy highlights the growing role of specialty pharmacy providers in making innovative cancer therapies accessible to patients.
Many modern oncology treatments involve specialized distribution and patient-support requirements. These services can include prescription processing, medication education, coordination with healthcare professionals, and ongoing assistance with treatment adherence.
For patients receiving oral cancer therapies at home, pharmacy support can be particularly important because treatment administration takes place outside the hospital or clinic environment.
Pharmacists and patient-support teams can help patients understand their medication instructions, address questions about treatment administration, and coordinate with prescribing physicians when additional support is needed.
Polaris Rx intends to use its pharmacy and patient-support capabilities to help patients receiving ZENBEXUS remain engaged with their prescribed treatment plans between clinic visits.
The company’s selection by Bristol Myers Squibb also reflects the importance of collaboration between pharmaceutical manufacturers and specialty dispensing providers in supporting the introduction of new oncology medicines.
As new treatment classes enter the market, effective distribution and patient-support infrastructure can help connect approved therapies with eligible patients and the healthcare teams responsible for their care.
Expanding Treatment Options for Relapsed Multiple Myeloma
The introduction of ZENBEXUS adds a new mechanism of action to the treatment landscape for adults with previously treated multiple myeloma.
The therapy’s approval is particularly relevant for patients who have received at least one prior line of treatment that included both a proteasome inhibitor and an immunomodulatory agent.
For these patients, disease relapse or treatment resistance can create additional challenges, making access to therapies with different mechanisms increasingly important.
The CELMoD mechanism offers a new approach to targeting malignant plasma cells through cereblon-mediated protein degradation.
Combined with daratumumab and dexamethasone, iberdomide represents a multi-agent treatment strategy supported by the findings from the EXCALIBER-RRMM clinical program.
Meanwhile, Polaris Rx’s selection by Bristol Myers Squibb is expected to support the dispensing and patient-service requirements associated with the therapy’s availability.
The partnership brings together an innovative oncology medicine and specialty pharmacy services focused on helping patients access and manage their treatment.
As the multiple myeloma treatment landscape continues to evolve, the introduction of new therapeutic classes, increasingly sensitive response assessments, and specialized patient-support services may contribute to expanding treatment opportunities.
For Polaris Rx, the selection to dispense ZENBEXUS represents an opportunity to support access to the first FDA-approved CELMoD therapy. For Bristol Myers Squibb, the launch of iberdomide represents an important addition to its multiple myeloma portfolio.
Ultimately, continued clinical evaluation, confirmatory evidence, and effective patient access will help establish the long-term role of ZENBEXUS in treating relapsed multiple myeloma.
About Polaris Rx
Experience the future of pharmacy care with Polaris Rx. As leaders in specialty, infusion, long-term and post-acute care, corrections, and PACE pharmacy solutions, Polaris Rx is elevating pharmacy standards by combining clinical expertise with advanced technology to improve outcomes, optimize costs, and enhance the patient experience. Founded in 2015, Polaris Rx is independently owned with more than 20 pharmacies nationwide.