SUMMARY

• TALVEY is not approved by the regulatory agencies for the treatment of patients with plasma cell leukemia (PCL).
• Johnson & Johnson does not recommend any practices, procedures, or usage that deviate from the product labeling or are not approved by the regulatory agencies.
• MonumenTAL-1 is an ongoing, open-label, phase 1/2 study evaluating the efficacy and safety of TALVEY in patients with relapsed or refractory multiple myeloma (RRMM).¹ 
  • Per protocol, patients with PCL (>2.0 x 10⁹/L plasma cells by standard differential), were excluded from enrollment.^1,2 
• Bernardi et al (2024)³ presented the clinical course of a 40-year-old male with primary plasma cell leukemia (pPCL) who was treated with TALVEY as 5^th line therapy.
• Other relevant literature has been identified in addition to the data summarized above.^4,5

PRODUCT LABELING

• TALVEY (talquetamab-tgvs) [Prescribing Information]. Horsham, PA: Janssen Biotech, Inc.; https://www.janssenlabels.com/package-insert/product-monograph/prescribing-information/TALVEY-pi.pdf.
• DARZALEX FASPRO (daratumumab and hyaluronidase-fihj) [Prescribing Information]. Horsham, PA: Janssen Biotech, Inc.; https://www.janssenlabels.com/package-insert/product-monograph/prescribing-information/DARZALEX+Faspro-pi.pdf.

CASE REPORT

Bernardi et al (2024)³ presented the clinical course of a 40yearold male with pPCL who was treated with TALVEY as 5^th line therapy.

• Upon diagnosis of pPCL, the patient presented with bone pain with severe anemia (7.6 g/dL hemoglobin), thrombopenia at 16 g/L, white blood cells count at 15.1 g/L with 47% circulating plasma cells, hypercalcemia, elevated lactate dehydrogenase (LDH) and β2‑microglobulin, an immunoglobulin A (IgA)-lambda of 31.6  g/L, free lambda light chains of 6,730 mg/L, and 80% bone marrow plasma cell infiltration. Chromosomal karyotyping revealed a complex karyotype with 17p13.1 loss and t(14;16), and positron emission tomography-computed tomography (PET-CT) revealed increased gastric and bone marrow activity. Gastric biopsy confirmed gastric infiltration by monoclonal plasma cells.
• The patient had received 4 prior lines of therapy before initiating TALVEY as 5^th line treatment. The 4 prior lines of therapy included:
  • Four cycles of KRD (carfilzomib, lenalidomide, dexamethasone) with weekly DARZALEX FASPRO added to cycles 3 and 4.  
  • Two cycles of VP-DACE (dexamethasone, cisplatin, doxorubicin, cyclophosphamide, etoposide, bortezomib, pomalidomide).
  • Autologous hematopoietic stem-cell transplantation (HSCT) with pomalidomide maintenance, followed by one cycle of PVD (bortezomib, dexamethasone, and pomalidomide)
  • Five cycles of elranatamab.
• Fifth-line therapy with TALVEY was started using sub-cutaneous (SC) step-up dosing of 0.01 mg/kg (day 1), 0.06 mg/kg (day 3), and 0.4 mg/kg (days 5 and 7), during which the patient developed grade 1 CRS requiring intravenous (IV) tocilizumab 8 mg/kg.
• After 2 cycles of TALVEY, the patient experienced explosive relapse characterized by a rapid increase in free light chain (FLC) and PET-CT evidence of radiologic relapse with multiple new hypermetabolic bone lesions, followed by death 3 weeks later.

LITERATURE SEARCH

A literature search of MEDLINE^®, Embase^®, BIOSIS Previews^®, and Derwent Drug File databases (and/or other resources, including internal/external databases) was conducted on 13 March 2026.