August 2026 in Hematology: 8 Developments That Advanced—and Challenged—Patient Care

August 2026 delivered consequential developments across malignant and classical hematology, led by 3 FDA approvals with the potential to alter treatment in multiple myeloma, warm autoimmune hemolytic anemia (wAIHA), and polycythemia vera (PV). The month also brought strong phase 3 data supporting earlier-line teclistamab, a highly active investigational combination for mantle cell lymphoma (MCL), and a new approach to degrading the historically difficult-to-target MYC oncogene.

A large phase 3 study found that intravenous arginine did not improve acute sickle cell disease (SCD) pain outcomes, challenging earlier evidence from smaller trials. The CDC also warned that B-cell–depleting therapies may increase the risk of severe or fatal arboviral neuroinvasive disease.

This month’s developments reflected hematology’s continued shift toward precision therapeutics and mechanism-based treatment while reinforcing the pharmacist’s role in safety monitoring, infection prevention, supportive care, and treatment access.

FDA Approves First CELMoD Regimen for Relapsed or Refractory Multiple Myeloma

The FDA granted accelerated approval to iberdomide (Zenbexus; Bristol Myers Squibb) in combination with daratumumab and hyaluronidase-fihj (Darzalex Faspro; Janssen Biotech) and dexamethasone for adults with relapsed or refractory multiple myeloma (RRMM) who received at least 1 prior line of therapy containing a proteasome inhibitor and an immunomodulatory agent.¹

Iberdomide is the first approved cereblon E3 ligase modulator, or CELMoD. It binds cereblon and promotes degradation of the transcription factors Ikaros and Aiolos, producing direct antimyeloma and immune-stimulatory effects.¹

Accelerated approval was supported by the ongoing phase 3 EXCALIBER-RRMM trial, which compared iberdomide, daratumumab, and dexamethasone with daratumumab, bortezomib, and dexamethasone. The minimal residual disease–negative complete response rate was 41% with the iberdomide regimen and 21% with the comparator. Progression-free survival (PFS) remains under evaluation as the confirmatory clinical-benefit end point.¹

The recommended iberdomide dosage is 1 mg orally once daily on days 1 through 21 of each 28-day cycle. Its prescribing information includes boxed warnings for embryo-fetal toxicity and serious venous and arterial thromboembolism. Additional risks include neutropenia, infection, and secondary malignancies. The drug is available only through the restricted Zenbexus Risk Evaluation and Mitigation Strategy program, making pharmacist oversight essential for REMS adherence, thromboprophylaxis assessment, adherence, and toxicity monitoring.¹

FDA Approves the First Treatment Specifically for Warm Autoimmune Hemolytic Anemia

Nipocalimab-aahu (Imaavy; Johnson & Johnson) became the first FDA-approved treatment specifically indicated for wAIHA. The approval covers adults and patients aged 12 years and older who are currently or were previously treated with corticosteroids.²

Nipocalimab is a neonatal Fc receptor blocker that reduces circulating pathogenic immunoglobulin G antibodies involved in red blood cell destruction. Unlike broad immunosuppressive approaches, the therapy targets a central mechanism of the disease.²

Approval was supported by the phase 2/3 ENERGY trial, which randomized 115 adults to receive nipocalimab or placebo with standard care. A durable hemoglobin response was achieved by 38.6% of patients receiving nipocalimab compared with 12.7% receiving placebo. The response was defined by hemoglobin improvement without prohibited rescue therapy or increased corticosteroid use.²

Nipocalimab is administered through weight-based intravenous infusion every 4 weeks following initial loading doses. Important safety considerations include infection, infusion-related reactions, and hypersensitivity. Vaccination status should be reviewed before treatment, and live vaccines should be avoided during therapy. Pharmacists can support infection screening, steroid taper coordination, infusion monitoring, and education regarding signs of hemolysis or disease recurrence.

FDA Approves First-in-Class Hepcidin Mimetic for Polycythemia Vera

The FDA approved rusfertide (Mimrylo; Takeda/Protagonist Therapeutics), a first-in-class hepcidin mimetic, for adults with PV whose erythrocytosis is not adequately controlled with existing therapy.³

PV causes excessive red blood cell production, increasing blood viscosity and the risk of thrombosis, stroke, and myocardial infarction. Many patients require repeated therapeutic phlebotomy to maintain hematocrit below 45%. Rusfertide mimics the iron-regulating hormone hepcidin, limiting the iron available for erythropoiesis.

In the phase 3 VERIFY trial, 293 adults requiring frequent phlebotomy despite standard therapy were randomly assigned to rusfertide or placebo. A clinical response—defined as no phlebotomy eligibility and no phlebotomy from weeks 20 through 32—was achieved by 76.9% of patients receiving rusfertide and 32.9% receiving placebo.³

Rusfertide also improved hematocrit control, reduced phlebotomy use, and improved fatigue. The most common adverse reactions included injection-site reactions and anemia. Pharmacists will need to monitor hemoglobin, hematocrit, iron parameters, injection tolerability, and concurrent cytoreductive therapy while helping prevent excessive iron restriction or treatment-related anemia.³

Teclistamab Improves Survival in Earlier-Line Multiple Myeloma

Phase 3 MajesTEC-9 findings supported moving teclistamab-cqyv (Tecvayli; Johnson & Johnson) into earlier RRMM. The trial enrolled 593 patients who received 1 to 3 previous lines and compared teclistamab monotherapy with pomalidomide, bortezomib, and dexamethasone or carfilzomib and dexamethasone.⁴

At a median follow-up of 17.3 months, teclistamab reduced the risk of progression or death by 71% compared with the standard regimens. The estimated 18-month PFS rate was 69.8% with teclistamab and 26.9% with standard therapy. Median PFS was not reached and was 8.2 months, respectively.⁴

The overall response rate was 84.5% with teclistamab compared with 54.2% in the control group. Complete response or better occurred in 65.9% and 16.8%, respectively. An interim overall survival analysis also favored teclistamab, with 18-month survival rates of 79.2% and 68.6%.⁴

Infection remains a central limitation. Grade 3 or 4 infections occurred in 41.6% of patients receiving teclistamab compared with 29.0% receiving standard therapy, and fatal infections occurred in 5.5% and 2.8%.⁴ Earlier use may therefore improve disease control while increasing the number of patients exposed to prolonged hypogammaglobulinemia, cytopenias, and infection risk. Pharmacists should help manage step-up dosing, cytokine release syndrome, antiviral and Pneumocystis jirovecii prophylaxis, immunoglobulin monitoring, vaccination, and intravenous immunoglobulin replacement when appropriate.⁴

Mosunetuzumab Plus Polatuzumab Produces High Response Rate After BTK Inhibitors

A fixed-duration combination of mosunetuzumab (Lunsumio; Genentech) and polatuzumab vedotin (Polivy; Genentech) produced an independently assessed overall response rate of 88.1% in patients with heavily pretreated RR MCL following Bruton tyrosine kinase inhibitor therapy. The complete response rate was 78.6%.⁵

The phase 2 trial included patients with clinically challenging disease characteristics, including TP53 abnormalities, blastoid or pleomorphic histology, and high Ki-67 expression. Participants had received a median of 3 prior lines, and 26% had undergone CAR T-cell therapy.⁵

At 15.9 months of median follow-up, median PFS was 18.6 months and median overall survival was 20.7 months. The median duration of response and duration of complete response had not been reached.⁵

Grade 3 or 4 adverse events occurred in 69% of patients, with neutropenia reported in 40.5%. Cytokine release syndrome occurred in 42.9% but was limited to grade 1 or 2. The subcutaneous administration of mosunetuzumab, fixed treatment duration, and lack of mandatory hospitalization could make the regimen relevant to outpatient care if confirmed in larger studies. Neither agent is currently approved for MCL in this combination.⁵

Phase 3 Trial Finds No Benefit With Intravenous Arginine for Sickle Cell Acute Pain

The phase 3 PECARN STArT trial found that intravenous arginine did not significantly shorten SCD-related acute pain episodes or reduce parenteral opioid use among children and young adults. The multicenter study randomized 274 patients at 10 US hospitals to intravenous arginine or saline placebo and was stopped early for futility.⁶

Median time to acute pain episode resolution was approximately 77 hours with arginine and 81 hours with placebo. Total parenteral opioid exposure also did not differ significantly between groups.⁶

The findings challenge positive results from earlier, smaller trials. More notably, outcomes varied substantially among participating hospitals: median time to pain resolution differed by as much as 61 hours, and mean parenteral opioid exposure differed by as much as 3.0 mg/kg.⁶

For hematology pharmacists, the findings do not support routine intravenous arginine use for SCD acute pain. The site-level variation instead strengthens the case for standardized vaso-occlusive episode pathways, rapid analgesic administration, scheduled reassessment, individualized opioid dosing, appropriate hydration, and multimodal supportive care.⁶

CDC Warns of Severe Arboviral Disease With B-Cell–Depleting Therapies

The CDC issued a Health Alert Network advisory warning that patients receiving B-cell–depleting or B-cell–modulating medications may face increased risk of severe, prolonged, or fatal arboviral neuroinvasive disease.⁷

Anti-CD20 therapies—including rituximab, obinutuzumab, ofatumumab, and other agents used in hematologic malignancies—can impair antibody production. Reported infections have included West Nile, eastern equine encephalitis, Powassan, Jamestown Canyon, La Crosse, Cache Valley, and Potosi viruses.⁷

Standard serologic testing may be falsely negative in B-cell–depleted patients. The CDC recommends considering molecular testing, including reverse-transcription polymerase chain reaction testing of blood or cerebrospinal fluid, when clinical suspicion remains high.⁷

No vaccines or targeted treatments are available for US-endemic arboviruses. Pharmacists should counsel patients receiving B-cell–directed therapy about mosquito and tick avoidance, appropriate repellent use, protective clothing, and prompt evaluation of fever, weakness, confusion, tremor, or other neurologic symptoms.⁷

RNA Degrader Offers a New Strategy for Targeting MYC in Multiple Myeloma

A first-in-class ribonuclease-targeting chimera, MYC-RiboTAC, reduced MYC expression and myeloma-cell survival in preclinical models. MYC is a major driver of multiple myeloma progression but has remained difficult to target with conventional small-molecule drugs.⁸

MYC-RiboTAC binds an internal ribosome entry site within MYC messenger RNA and recruits RNase L to destroy the transcript before it can be translated into protein. Antimyeloma activity was observed in cell lines, patient-derived samples, and xenograft models.⁸

The degrader retained activity in models replicating the bone marrow microenvironment and demonstrated synergy with carfilzomib, lenalidomide, and pomalidomide. These therapies may increase RNase L expression, enhancing RNA-degrader activity.⁸

The findings remain preclinical. Human development will require evidence of adequate exposure, tumor selectivity, tolerability, and sustained MYC suppression. Biomarker strategies may also be needed to identify tumors with sufficient MYC dependence and RNase L activity.⁸

Looking Ahead

August’s developments introduced clinically meaningful treatments across plasma cell malignancies, autoimmune cytopenias, and myeloproliferative neoplasms. Iberdomide expands the multiple myeloma armamentarium through a new generation of cereblon modulation, while nipocalimab and rusfertide directly address central disease mechanisms in wAIHA and PV.

At the same time, the month reinforced that therapeutic innovation brings new responsibilities. Earlier-line bispecific therapy requires stronger infection-prevention infrastructure. B-cell–directed treatment demands awareness of uncommon but potentially fatal infections. Negative SCD trial results require clinicians to reassess ineffective interventions while examining variation in existing care.

For pharmacists, these developments create immediate responsibilities involving REMS compliance, supportive care, vaccination, infection prophylaxis, laboratory monitoring, infusion management, patient education, and coordination across community and specialized hematology settings.

REFERENCES

1. FDA grants accelerated approval to iberdomide with daratumumab and hyaluronidase-fihj and dexamethasone for multiple myeloma. News release. FDA. August 13, 2026. Accessed August 31, 2026. https://www.fda.gov/drugs/resources-information-approved-drugs/fda-grants-accelerated-approval-iberdomide-daratumumab-and-hyaluronidase-fihj-and-dexamethasone

2. FDA approves first drug for warm autoimmune hemolytic anemia. News release. FDA. August 25, 2026. Accessed August 31, 2026. https://www.fda.gov/drugs/news-events-human-drugs/fda-approves-first-drug-warm-autoimmune-hemolytic-anemia

3. FDA approves first drug of its kind for polycythemia vera, a rare blood disorder. News release. FDA. Released August 28, 2026. Accessed August 31, 2026. https://www.fda.gov/news-events/press-announcements/fda-approves-first-drug-its-kind-polycythemia-vera-rare-blood-disorder

4. Touzeau C, Mina R, Quach H, et al. Teclistamab in Multiple Myeloma with One to Three Previous Lines of Therapy. N Engl J Med. 2026;395(5):440-453. doi:10.1056/NEJMoa2603870

5. Budde LE, Kamdar M, Assouline SE, et al. Mosunetuzumab plus polatuzumab vedotin for relapsed/refractory MCL after BTK inhibitor therapy: a phase 2 study. Blood. 2026;148(6):682-692. doi:10.1182/blood.2025032422

6. Morris CR, Hatabah D, Korman R, et al. Arginine Therapy for Sickle Cell Disease Acute Pain Episodes: The STArT Randomized Clinical Trial. JAMA. Published online August 19, 2026. doi:10.1001/jama.2026.13310

7. CDC. Risk of severe arboviral disease in patients receiving B-cell–depleting or B-cell–modulating medications. Health Alert Network Health Advisory. Updated August 11, 2026. Accessed August 31, 2026. https://www.cdc.gov/han/php/notices/han00532.html

8. Maisano D, Wang T, Kulp SB, et al. A first-in-class RNA degrader reduces c-MYC expression and myeloma cell survival in preclinical models. Blood. Published online July 29, 2026. doi:10.1182/blood.2026033241