GPRC5D as a novel target for the treatment of multiple myeloma: a narrative review

Multiple myeloma is a genetically complex and heterogenous malignancy with a 5-year survival rate of approximately 60%. Despite advances in therapy, patients experience cycles of remission and relapse, with each successive line of therapy associated with poorer outcomes; therefore, therapies with different mechanisms of action against new myeloma antigens are needed. G protein-coupled receptor class C group 5 member D (GPRC5D) has emerged as a novel therapeutic target for the treatment of multiple myeloma. We review the biology and target validation of GPRC5D, and clinical data from early phase trials of GPRC5D-targeting bispecific antibodies, talquetamab and forimtamig, and chimeric antigen receptor T cell (CAR-T) therapies, MCARH109, OriCAR-017, and BMS-986393. In addition to adverse events (AEs) associated with T-cell-redirection therapies irrespective of target, a consistent pattern of dermatologic and oral AEs has been reported across several trials of GPRC5D-targeting bispecific antibodies, as well as rare cerebellar events with CAR-T therapy. Additional studies are needed to understand the underlying mechanisms involved in the development of skin- and oral-related toxicities. We review the strategies that have been used to manage these GPRC5D-related toxicities. Preliminary efficacy data showed overall response rates for GPRC5D-targeting T-cell-redirecting therapies were ≥64%; most responders achieved a very good partial response or better. Pharmacokinetics/pharmacodynamics showed that these therapies led to cytokine release and T-cell activation. In conclusion, results from early phase trials of GPRC5D-targeting T-cell-redirecting agents have shown promising efficacy and manageable safety profiles, including lower infection rates compared with B-cell maturation antigen- and Fc receptor-like protein 5-targeting bispecific antibodies. Further clinical trials, including those investigating GPRC5D-targeting T-cell-redirecting agents in combination with other anti-myeloma therapies and with different treatment modalities, may help to elucidate the future optimal treatment regimen and sequence for patients with multiple myeloma and improve survival outcomes. Video Summary.

Results of a Time and Motion Survey Regarding Subcutaneous versus Intravenous Administration of Daratumumab in Patients with Relapsed or Refractory Multiple Myeloma

Purpose

Daratumumab (DARA) is a humanized anti-CD38 monoclonal antibody and approved as monotherapy or in combination with standard of care regimens for the treatment of multiple myeloma (MM). DARA intravenous (IV) administration is time-consuming; availability of DARA subcutaneous (SC) is expected to reduce this burden. A time and motion survey was undertaken to elicit healthcare providers’ (HCPs’) understanding of the workflow and time estimates for administration of DARA IV and SC (beyond treatment time) in patients with relapsed/refractory MM.

Patients and Methods

This web-based, prospective survey collected data from HCPs at sites that actively enrolled patients in the phase 3 COLUMBA trial, a multicenter, noninferiority study of DARA IV versus DARA SC. Data collection included time actively spent on pre-specified drug preparation and drug administration/patient care activities; active HCP and chair time were extrapolated for first and subsequent treatments.

Results

Compared with DARA IV, DARA SC reduced median total active HCP time by 63.8% (from 265.9 to 96.3 minutes) and 49.5% (from 179.2 to 90.4 minutes) for first and subsequent treatments, respectively. When extrapolated to the anticipated number of treatments per year (23 in Year 1 and 13 in Year 2, per label), estimated active HCP time per patient was reduced by 50% in Years 1 (from 70.1 to 34.8 hours) and 2 (from 38.8 to 19.6 hours) for DARA SC versus DARA IV. Estimated chair time for DARA SC was decreased by 97% versus DARA IV for first (from 456.9 to 13.3 minutes) and subsequent treatments (from 238.0 to 8.1 minutes).

Conclusion

These results suggest that DARA SC is associated with less active HCP involvement during drug preparation and drug administration/patient care compared with DARA IV, potentially reducing burdens on patients and caregivers and creating efficiencies for HCPs and healthcare facilities, allowing more patients access to care.

Subcutaneous daratumumab in patients with relapsed or refractory multiple myeloma: Part 2 of the open-label, multicenter, dose-escalation phase 1b study (PAVO)

Intravenous daratumumab is approved for the treatment of multiple myeloma. In Part 1 of the PAVO study, a mix-and-deliver subcutaneous formulation of daratumumab with recombinant human hyaluronidase PH20 (rHuPH20) was well tolerated, with low rates of infusion-related reactions and similar efficacy to intravenous daratumumab. Part 2 of PAVO evaluated a concentrated, pre-mixed co-formulation of daratumumab and rHuPH20 (DARA SC). Patients with ≥2 prior lines of therapy, including a proteasome inhibitor and immunomodulatory drug, received daratumumab (1800 mg) and rHuPH20 (30,000 U) in 15 mL subcutaneously over 3-5 minutes per the approved intravenous monotherapy dosing schedule. Primary endpoints were daratumumab trough concentration at the end of weekly dosing (just prior to the Cycle 3 Day 1 dose) and safety. Twenty-five patients were enrolled in PAVO Part 2. DARA SC achieved daratumumab trough concentrations similar to or greater than intravenous daratumumab 16 mg/kg. The adverse event profile of DARA SC was consistent with intravenous daratumumab, with no new safety concerns and a lower infusion-related reaction rate. At a median follow-up of 14.2 months, the overall response rate was 52%, median duration of response was 15.7 months, and median progression-free survival was 12.0 months. DARA SC 1800 mg was well tolerated in relapsed/refractory multiple myeloma, with a low infusion-related reaction rate and reduced administration time. Daratumumab serum concentrations following DARA SC were consistent with intravenous dosing, and deep and durable responses were observed. Based on these results, ongoing studies are investigating DARA SC in multiple myeloma and other conditions. (ClinicalTrials.gov identifier: 02519452).

Greater treatment satisfaction in patients receiving daratumumab subcutaneous vs. intravenous for relapsed or refractory multiple myeloma: COLUMBA clinical trial results

PURPOSE

The phase III COLUMBA study evaluated daratumumab (DARA) intravenous (IV) and subcutaneous (SC) in patients with relapsed or refractory multiple myeloma. Here, we report patient-reported satisfaction with therapy (SWT) in COLUMBA.

METHODS

DARA IV or DARA SC was administered weekly (cycles 1-2), every 2 weeks (cycles 3-6), and every 4 weeks (cycles 7 +). Patients completed a modified version of the Cancer Therapy Satisfaction Questionnaire (CTSQ) at weekly (cycles 1-2) and monthly (cycles 3 +) intervals and at the end of treatment. Results for each item and the SWT domain score were summarized using descriptive statistics. The distribution of responses for individual items was calculated for each assessment. The proportion of patients for whom SWT domain score change from first assessment met or exceeded the minimally important difference (MID) of 5.9 points was calculated at each assessment time point.

RESULTS

Two-hundred fifty-nine patients were randomized to DARA IV and 263 to DARA SC. Mean scores for SWT domain questions were high and largely positive during treatment. Responses indicating positive perceptions of therapy were given by a numerically greater proportion of patients in the DARA SC group than the DARA IV group for most questions. Changes from the first assessment in SWT domain scores met or exceeded the MID for an average of ~ 40% of patients.

CONCLUSION

In COLUMBA, modified CTSQ results suggest patients in the DARA SC group were more satisfied with their cancer therapy than those in the DARA IV group.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT03277105. Registered September 8, 2107.

Subcutaneous daratumumab plus standard treatment regimens in patients with multiple myeloma across lines of therapy (PLEIADES): an open-label Phase II study

Daratumumab is a CD38-targeting monoclonal antibody approved for intravenous (IV) infusion for multiple myeloma (MM). We describe the Phase II PLEIADES study of a subcutaneous formulation of daratumumab (DARA SC) in combination with standard-of-care regimens: DARA SC plus bortezomib/lenalidomide/dexamethasone (D-VRd) for transplant-eligible newly diagnosed MM (NDMM); DARA SC plus bortezomib/melphalan/prednisone (D-VMP) for transplant-ineligible NDMM; and DARA SC plus lenalidomide/dexamethasone (D-Rd) for relapsed/refractory MM. In total, 199 patients were treated (D-VRd, n = 67; D-VMP, n = 67; D-Rd, n = 65). The primary endpoints were met for all cohorts: the ≥very good partial response (VGPR) rate after four 21-day induction cycles for D-VRd was 71·6% [90% confidence interval (CI) 61·2-80·6%], and the overall response rates (ORRs) for D-VMP and D-Rd were 88·1% (90% CI 79·5-93·9%) and 90·8% (90% CI 82·6-95·9%). With longer median follow-up for D-VMP and D-Rd (14·3 and 14·7 months respectively), responses deepened (ORR: 89·6%, 93·8%; ≥VGPR: 77·6%, 78·5%), and minimal residual disease-negativity (10^-5 ) rates were 16·4% and 15·4%. Infusion-related reactions across all cohorts were infrequent (≤9·0%) and mild. The median DARA SC administration time was 5 min. DARA SC with standard-of-care regimens demonstrated comparable clinical activity to DARA IV-containing regimens, with low infusion-related reaction rates and reduced administration time.

A drug-drug interaction study of ibrutinib with moderate/strong CYP3A inhibitors in patients with B-cell malignancies

This was an open-label, multicenter, phase-1 study to evaluate the drug interaction between steady-state ibrutinib and moderate (erythromycin) and strong (voriconazole) CYP3A inhibitors in patients with B-cell malignancies and to confirm dosing recommendations. During cycle 1, patients received oral ibrutinib 560 mg qd alone (Days 1-4 and 14-18), and ibrutinib 140 mg (Days 5-13; 19-27) plus erythromycin 500 mg tid (Days 5-11) and voriconazole 200 mg bid (Days 19-25). Twenty-six patients (median [range] age: 64.5 [50-88] years) were enrolled. Geometric mean ratio (90% confidence intervals) after co-administration of ibrutinib 140 mg with erythromycin and voriconazole was 74.7 (53.97-103.51) and 143.3 (107.77-190.42), respectively, versus ibrutinib 560 mg alone. The most common (≥20%) adverse events were diarrhea (27%) and neutropenia (23%). The results demonstrate that ibrutinib 140 mg with voriconazole or erythromycin provides exposure within the clinical range for patients with B-cell malignancies.

Results from a Phase IIA Parallel Group Study of JNJ-40346527, an Oral CSF-1R Inhibitor, in Patients with Active Rheumatoid Arthritis despite Disease-modifying Antirheumatic Drug Therapy

Objective.

To assess the efficacy and safety of JNJ-40346527, a selective inhibitor of colony-stimulating factor-1 (CSF-1) receptor kinase that acts to inhibit macrophage survival, proliferation, and differentiation in patients with active rheumatoid arthritis (RA) despite disease-modifying antirheumatic drug (DMARD) therapy.

Methods.

In this randomized, double-blind, placebo-controlled, parallel group study, adults were randomized (2:1) to receive oral JNJ-40346527 100 mg or placebo twice daily through Week 12. Patients with RA had disease activity [≥ 6 swollen/≥ 6 tender joints, C-reactive protein (CRP) ≥ 0.8 mg/dl] despite DMARD therapy for ≥ 6 months. The primary endpoint was change from baseline at Week 12 in the 28-joint Disease Activity Score with CRP (DAS28-CRP). Pharmacokinetic/pharmacodynamic analyses were also performed, and safety was assessed through Week 16.

Results.

Ninety-five patients were treated (63 JNJ-40346527, 32 placebo); 8 patients discontinued treatment (6 JNJ-40346527, 2 placebo) through Week 12. Mean improvements in DAS28-CRP from baseline to Week 12 were 1.15 for the JNJ-40346527 group and 1.42 for the placebo group (p = 0.30); thus, a statistically significant difference was not observed for the primary endpoint. Pharmacokinetic exposure to JNJ-40346527 and its active metabolites was above the projected concentration needed for pharmacologic activity, and effective target engagement and proof of activity were demonstrated by increased levels of CSF-1 and decreased CD16+ monocytes in JNJ-40346527–treated, but not placebo-treated, patients. Thirty-seven (58.7%) JNJ-40346527–treated and 16 (50.0%) placebo-treated patients reported ≥ 1 adverse event (AE); 1 (1.6%) JNJ-40346527–treated and 3 (9.4%) placebo-treated patients reported ≥ 1 serious AE.

Conclusion.

Although adequate exposure and effective peripheral target engagement were evident, JNJ-40346527 efficacy was not observed in patients with DMARD-refractory active RA. ClinicalTrials.gov identifier: NCT01597739. EudraCT Number: 2011-004529-28.

Assessing extracranial carotid stenosis: magnetic resonance angiography, duplex scanning, and digital angiography

Recent data have demonstrated the efficacy of carotid endarterectomy in patients with severe, symptomatic carotid stenosis. In this context, our study analyzes the role of carotid testing with magnetic resonance angiography and carotid duplex scanning, as compared to arterial digital subtraction angiography.

Knotting and handling characteristics of coated synthetic absorbable sutures

The purpose of this study was to evaluate the knotting and handling characteristics of the new coated synthetic absorbable sutures. When compared to the coated polyglactin 910 sutures, the coated polyglycolic acid sutures displayed a lower coefficient of friction, encountered less tissue drag forces, and exhibited less flexural rigidity. In the case of sizes O, 2-O, and 3-O coated polyglycolic sutures, knot security was achieved with one less throw than with similar sizes of coated polyglactin 910 sutures. On the basis of these comprehensive mechanical performance tests, the knotting and handling characteristics of the coated polyglycolic acid sutures were judged to be superior to that of the coated polyglactin 910 sutures.