Daratumumab subcutaneous formulation for the treatment of multiple myeloma

A validated LC-MS/MS method for the quantitation of daratumumab in rat serum using rapid tryptic digestion without IgG purification and reduction

Daratumumab, a humanized monoclonal antibody utilized in treating immunoglobulin light-chain amyloidosis and relapsed/refractory multiple myeloma, was quantified in rat serum through a simple, economical and effective liquid chromatography tandem-mass spectrometry (LC-MS/MS) method. A surrogate peptide, LLIYDASNR, derived from trypsin hydrolysis, was quantitatively analyzed with LLIYDASN [13C6, 15N4] RAT as an internal standard. This corrected variations from sample pretreatment and mass spectrometry response, involving denaturation and trypsin hydrolysis in a two-step process lasting approximately 1 hour. Methodological validation demonstrated a linear range of 1 µg/mL to 1000 µg/mL in rat serum. Precision, accuracy, matrix effect, sensitivity, stability, selectivity, carryover, and interference met acceptance criteria. The validated LC-MS/MS approach was successfully applied to a pharmacokinetic study of daratumumab in rats at an intravenous dose of 15 mg/kg.

Clinical Pharmacokinetics and Pharmacodynamics of Daratumumab

Daratumumab is a fully human, monoclonal immunoglobulin G1 and a first-in-class CD38-targeting drug approved by the US Food and Drug Administration for the treatment of patients with relapsed/refractory and newly diagnosed multiple myeloma or newly diagnosed light-chain amyloidosis. CD38 is heavily expressed on malignant myeloma cells, and daratumumab exerts anti-myeloma activity via immune-mediated mechanisms, direct induction of apoptosis, and immunomodulation. Daratumumab is used as monotherapy or in combination with standard-of-care myeloma therapies, including proteasome inhibitors, immunomodulatory agents, DNA-alkylating agents, and corticosteroids. Following an intravenous infusion, daratumumab exhibits nonlinear pharmacokinetics (PK), as clearance decreases with higher doses and over time because of target-mediated effects. Dosing schedules vary depending on indications and co-administered drugs, but generally daratumumab is administered weekly for 6-9 weeks followed by a less frequent dosing regimen, once every 2-4 weeks. Daratumumab exposure is strongly correlated with efficacy, and the exposure-efficacy relationship follows a maximal effect model, whereas exposure is not correlated with safety endpoints. The approved dose of 16 mg/kg of daratumumab results in the saturation of 99% of the target at the end of weekly dosing in most patients, and high target saturation is maintained over time during the less frequent dosing schedule. Infusion-related reactions are frequently observed in patients given daratumumab, particularly with the first infusion, thus prompting long durations of infusion (~ 7 h) and splitting of the first dose across 2 days. This led to the development of a subcutaneous delivery formulation for daratumumab (Dara-SC). Dara-SC provides a similar efficacy and safety profile to intravenous daratumumab (Dara-IV) but has a much lower rate of infusion-related reactions and a shorter infusion time. Exposure-response relationships for efficacy and safety endpoints were similar between Dara-SC and Dara-IV, and co-administered drugs with either Dara-IV or Dara-SC do not significantly affect daratumumab PK. Except for baseline myeloma type and albumin level, none of the other investigated disease and patient characteristics (renal/hepatic function, age, sex, race, weight, Eastern Cooperative Oncology Group performance status) was identified to have clinically relevant effects on exposure to daratumumab monotherapy or combination therapy regimens. Dara-IV exposure was significantly lower in patients with immunoglobulin G myeloma compared with patients with non-immunoglobulin G myeloma (p < 0.0001) and in patients with a lower albumin level, whereas the overall response rate was similar regardless of the myeloma type and albumin level. Daratumumab dose adjustment is not currently recommended based on disease and patient characteristics.

Efficacy of maintenance treatment in patients with multiple myeloma: a systematic review and network meta-analysis

BACKGROUND

Despite conspicuous advances in innovating novel drugs and combination regimens in multiple myeloma (MM) in recent decades, the most appropriate maintenance regimens after inductive therapy are still controversial and opaque.

OBJECTIVE

We aimed to identify the most effective maintenance treatment for newly diagnosed multiple myeloma (NDMM) patients via network meta-analysis.

METHOD

We searched PubMed, Embase, Cochrane Library, Scopus, and Google Scholars from inception to April, 2022. Odds ratios (ORs) were generated for dichotomous variants. The primary endpoint was overall survival (OS).

RESULTS

Eventually a total of 19 trials, including 11 treatments and 8337 patients, were included in this analysis. For OS, lenalidomide (OR ranged from 1.61 to 1.99) and daratumumab (OR ranged from 1.83 to 2.41) showed significant efficacy over placebo. Maintenance therapy comprising lenalidomide-carfilzomib (OR ranged from 3.19 to 6.95), lenalidomide-prednisone (OR ranged from 2.62 to 4.44), bortezomib-thalidomide (OR ranged from 2.48 to 3.64), daratumumab (OR ranged from 2.0 to 2.98), lenalidomide (OR ranged from 1.4 to 3.19), ixazomib (OR ranged from 1.36 to 2.05), thalidomide (OR ranged from 1.5 to 1.86) demonstrated significant effects in prolonging PFS compared with placebo; Among the efficient therapies, lenalidomide-carfilzomib was significantly superior to lenalidomide (OR ranged from 2.18 to 2.20), daratumumab (OR ranged from 1.49 to 2.66) and ixazomib (OR ranged from 2.75 to 3.57).

CONCLUSION

Considering OS and PFS, lenalidomide-carfilzomib should be recommended as the best therapy. In clinical practice, this must be weighed against the increased risk of adverse events and financial burden. However, more head-to-head studies are needed to confirm these findings.