Efficacy and Tolerability of Ixazomib, Daratumumab and Low Dose Dexamethasone (Ixa Dara dex) in Unfit and Frail Newly Diagnosed Multiple Myeloma (NDMM) Patients; Results of the Interim Efficacy Analysis of the Phase II HOVON 143 Study

Abstract

Introduction Elderly non-transplant eligible newly diagnosed multiple myeloma (nte-NDMM) patients also benefit from novel therapies, however, overall survival (OS) is inferior in unfit and frail compared to fit patients as defined by the International Myeloma Working Group (IMWG) frailty index. This is caused by a high discontinuation rate due to toxicity. Therefore, a less toxic effective treatment for unfit and frail patients is needed. In view of the favorable safety profile of ixazomib (Ixa) and daratumumab (Dara), we investigated the efficacy and feasibility of treatment with Ixa and Dara plus low dose dexamethasone (Ixa-Dara-dex) in unfit and frail patients. This trial was registered at www.trialregister.nlwww.trialregister.nl as NTR6297. Methods In this prospective multicenter phase II trial, treatment consisted of nine 28 day-induction cycles consisting of Ixa 4 mg (days 1, 8, 15), Dara 16 mg/kg (cycle 1-2: days 1, 8, 15, 22; cycle 3-6: days 1, 15; cycle 7-9: day 1) and dex (in combination with Dara; cycle 1-2: 20 mg; subsequent cycles 10 mg) followed by maintenance therapy with Ixa (days 1, 8, 15, 29, 36, 43) and Dara (day 1) of 8-week cycles, until progression for a maximum of 2 years. A pre-specified efficacy analysis was planned for the first eligible 23 unfit and 23 frail patients separately at the time the data of the first 9 cycles induction therapy was available. Inclusion criteria were unfit or frail NDMM patients according to the IMWG frailty index. Main exclusion criteria were severe cardiac dysfunction, chronic obstructive pulmonary disease with an FEV1 <50% of expected and a creatinine clearance of <20 ml/minute. We here report the overall response rate (ORR) on induction treatment, progression free survival (PFS) and OS, treatment discontinuation and toxicity of the first 23/65 eligible unfit and 23/65 frail patients during induction therapy. In addition, we present the mortality rate for all patients who were included in the study (65 unfit, 67 frail), with data cut-off June 18, 2019. Results The demographics of the first 23 unfit and 23 frail patients are described in Table 1. Median follow-up of these first 23 unfit and 23 frail patients is 12.7 months (range 9.1-18.3) and 13.4 months (range 9.2-17.7), respectively. ORR during induction was 87% in unfit (48% partial response [PR] and 39% very good partial response [VGPR]) and 78% in frail (48% PR, 26% VGPR, 4% stringent complete response). Nine months PFS rates were 78% (95% Confidence Interval [CI] 55-90) and 61% (95% CI 38-77), respectively. Nine months OS rates were 100% and 83% (95% CI 60-93), respectively. Sixteen/23 (70%) unfit and 14/23 (61%) frail patients completed induction treatment with Ixa-Dara-dex. Reasons for treatment discontinuation were progressive disease (PD, n=5), toxicity (n=1) and incompliance (n=1) in unfit and intercurrent death (n=3, all within 3 cycles), PD (n=2), incompliance (n=2) and other reasons (n=2) in frail. The median and inter-quartile range of relative dose intensity (RDI) for respectively unfit and frail were 0.96 and 0.91 for Ixa, 0.98 and 0.96 for Dara and 1.0 and 0.99 for dex. Toxicity is described in Table 2. Hematological toxicity was limited, being mainly neutropenia (in unfit both 4% grade 3 and 4; in frail 4% grade 3 and 13% grade 4) and thrombocytopenia occurring only in frail (17% grade 3, 4% grade 4). Non-hematological toxicity was manageable, with grade 3 infections occurring in 9% of both unfit and frail patients. In both arms, there were no infusion related reactions and only 4% grade 3 neuropathy was reported. Additionally, we investigated the mortality rate of all included 65 unfit and 67 frail patients, with a limited follow-up of 7.1 months (range 1-18.3) and 8.8 months (range 0.4-17.7), respectively. The mortality rate was only 2% in unfit (1/65 due to PD). Thirteen/67 (19%) of frail patients died, which was caused by infections (n=6; 3 pneumonia, 1 influenza B, 1 erysipelas), sudden death (n=2), organ dysfunction (n=2), incompliance (n=1) and PD (n=2). Early death rate (≤3 months of registration) was 0% in unfit and 8/67 (12%) in frail. Conclusion Ixa-Dara-dex is an effective therapeutic regimen in unfit patients with limited toxicity, not giving rise to (early) mortality. Additionally, in the majority of frail patients this regimen is active and feasible. However, better identification and support of those patients is warranted, as we observed early mortality due to vulnerability and infections. Disclosures Van De Donk: Janssen Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; AMGEN: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer: Membership on an entity's Board of Directors or advisory committees; Servier: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees. Sonneveld:SkylineDx: Research Funding; Takeda: Honoraria, Research Funding; Karyopharm: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; BMS: Honoraria; Amgen: Honoraria, Research Funding. Levin:Amgen: Membership on an entity's Board of Directors or advisory committees, Other: Educational grant ; Janssen: Membership on an entity's Board of Directors or advisory committees, Other: Educational Grant; Roche: Membership on an entity's Board of Directors or advisory committees, Other: Educational Grant; Abbvie: Membership on an entity's Board of Directors or advisory committees, Other: Educational Grant; Takeda: Membership on an entity's Board of Directors or advisory committees, Other: Educational grant . Zweegman:Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding.

Daratumumab for the Management of Newly Diagnosed and Relapsed/Refractory Multiple Myeloma: Current and Emerging Treatments

“…Daratumumab was also studied in association with ixazomib and low dose dexamethasone in phase II HOVON-143 trial ( 29 ) for unfit and frail patients according to the International Myeloma Working Group Frailty Index (IMWG-FI). Treatment consisted of nine cycles with ixazomib (4 mg on days 1, 8, 15), daratumumab (16 mg/kg weekly cycles 1 and 2; every two weeks cycles 3–6; day 1 cycles 7–9), dexamethasone (in combinations with daratumumab 10 mg).…”

Diagnostic and Therapeutic Challenges in the Management of Intermediate and Frail Elderly Multiple Myeloma Patients

“…Preliminary data showed an overall response rate (ORR) of 74% and 78% in intermediate and frail patients and a median PFS of 23 and 12 months, respectively. Preliminary analysis showed that discontinuation rates and toxic deaths were low in intermediate-fit patients, but reached 7% and 9% in frail patients, suggesting that this latter group might benefit from even gentler approaches [59].…”

The Role of Monoclonal Antibodies in the First-Line Treatment of Transplant-Ineligible Patients with Newly Diagnosed Multiple Myeloma

“…Remarkably, new phase II trials are exploring frailty-tailored approaches including mAbs in less toxic combinations in NDMM patients. For instance, the HOVON group is evaluating the combination of daratumumab, ixazomib, and low-dose dexamethasone in intermediate-fit and frail patients [ 28 ]. The IFM2017_03 study will evaluate subcutaneous daratumumab plus lenalidomide vs. standard Rd in frail patients as a dexamethasone-sparing strategy, since steroids are scarcely tolerated in the long term, particularly in elderly populations (NCT03993912).…”

“…Many other treatment combinations, based on various mAbs, are currently under investigation. Among them, the HOVON 143 phase II trial enrolled intermediate-fit and frail NDMM patients to evaluate the efficacy and safety of a first-line treatment with the association of daratumumab, ixazomib, and low-dose dexamethasone [ 28 ]. The treatment schedule included an induction phase followed by maintenance therapy.…”