Labotka, Richard

Background CD38 is highly expressed on MM cells, hence anti-CD38 agents are of interest as a therapeutic approach in MM. The anti-CD38 monoclonal antibody, dara, as mono- or combination therapy, has substantially improved efficacy outcomes in RRMM, including in heavily pretreated pts. However, many pts relapse and new therapeutic approaches are needed, particularly for pts R/R to dara. TAK-169 is a dimeric fusion protein of an anti-CD38 antibody single chain variable fragment fused to a modified Shiga-like toxin-A subunit. Its unique mechanism of action involves specific binding to CD38+ cells, forced internalization into the target cells, retrograde transport to the cytosol, and irreversible, enzymatic inactivation of target cell ribosomes to cause apoptosis. TAK-169 showed potent, rapid in vitro activity on CD38-expressing cell lines and in vivo efficacy in MM mouse xenograft tumor models with a wide CD38 expression range when administered intravenously (IV) once weekly (QW) or once every 2 weeks (Q2W). Activity was also shown in ex vivo assays from 6 pt bone marrow aspirate (BMA) samples, including from a dara-resistant pt (EC50 5 nM). TAK-169 retained in vitro activity in the presence of dara with modest shifts in EC50 noted at higher dara concentrations. In contrast to dara, TAK-169 has direct tumor cell kill activity that is independent of a pt's immune function status and may therefore be effective in a dara-resistant setting. Accordingly, this phase 1 study will assess safety, tolerability, preliminary efficacy, pharmacokinetics (PK) and pharmacodynamics (PD) of TAK-169 in RRMM. Methods This first-in-human, multicenter, open-label study (NCT04017130; Figure) comprises dose escalation (Part 1) and expansion (Part 2). Eligible pts must be aged ≥18 years with a confirmed diagnosis of MM. Pts enrolled in Part 1 should not be candidates for available therapies known to confer clinical benefit in RRMM. In part 2, pts enrolled should have received ≥3 prior lines of therapy, or ≥2 if one included a PI and IMiD combined. Prior anti-CD38 therapy (including dara) is permitted, except in the Part 2 anti-CD38 therapy-naive expansion cohort. In Part 1, the primary objective is to assess safety/tolerability of TAK-169 in pts with RRMM, and determine maximum tolerated dose/recommended Phase 2 dose (MTD/RP2D). Secondary objectives include efficacy, PK, PD and immunogenicity of TAK-169. Approximately 60 pts are planned to be enrolled to receive IV TAK-169 QW on Days 1/8/15/22 in 28-day cycles. Dosing will start at 50 μg/kg, with subsequent dose levels of 100, 200, 335, 500, 665 μg/kg. A 2nd Q2W dose escalation cohort may be initiated, starting at the QW MTD. The Bayesian Logistic Regression Model with overdose control will be used for dose escalation cohort 2 and for all subsequent dose escalation cohorts, and other non-DLT-safety, clinical, PK, and PD data will be considered. In Part 2, the primary objective is preliminary evaluation of TAK-169 clinical activity in RRMM. Secondary objectives include further evaluating safety, efficacy, PK, PD, and immunogenicity of TAK-169. Part 2 will enroll approximately 54 pts into dara RR (QW and Q2W dosing) and anti-CD38 therapy-naïve (QW dosing) cohorts. TAK-169 will be administered at the MTD/RP2D (QW and Q2W) determined in Part 1. Response will be monitored longitudinally using orthogonal approaches. M-protein levels in serum and urine will be measured each cycle to determine objective responses by International Myeloma Working Group (IMWG) criteria. Minimal residual disease status in pts suspected to be at complete response will be assessed. Circulating free DNA (cfDNA) will be collected from longitudinal plasma samples for disease monitoring. Baseline cytogenetic data will be collected, and TAK-169 efficacy will be assessed in pts with high-risk cytogenetics. Serial blood samples will be used to characterize PK and PD of TAK-169 after IV administration, and to assess the presence of antidrug antibodies. BMA samples collected at screening will be used to evaluate baseline expression of candidate biomarkers. Toxicity will be evaluated using National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE) version 5. Efficacy analyses will use descriptive statistics with a 95% confidence interval and the Kaplan-Meier method. PK parameters and immunogenicity status will be summarized using descriptive statistics. Recruitment is ongoing. Figure Disclosures Kumar: Celgene: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Takeda: Research Funding. Cornell:Takeda: Consultancy; KaryoPharm: Consultancy. Landgren:Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Other: IDMC; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Theradex: Other: IDMC; Adaptive: Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Ailawadhi:Cellectar: Research Funding; Pharmacyclics: Research Funding; Janssen: Consultancy, Research Funding; Celgene: Consultancy; Amgen: Consultancy, Research Funding; Takeda: Consultancy. Higgins:Molecular Templates, Inc.: Employment, Equity Ownership. Willert:Molecular Templates: Employment. Waltzman:Molecular Templates, Inc.: Employment, Equity Ownership. Lin:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment, Equity Ownership. Zhang:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Lublinsky:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Dash:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Hanley:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Manoharan:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Leichter:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Ottinger:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Labotka:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Newcomb:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment, Equity Ownership. Vorog:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. OffLabel Disclosure: TAK-169 is a dimeric fusion protein of an anti-CD38 antibody single chain variable fragment fused to a modified Shiga-like toxin-A subunit

Abstract Introduction Maintenance therapy has been extensively explored as a strategy for prolonging the duration of disease control and potentially survival following ASCT. To date, only lenalidomide has been approved for this indication. However, lenalidomide maintenance is associated with the development of second primary malignancies and tolerability issues. PIs are a backbone of MM treatment, and bortezomib-based maintenance has shown promising activity post-ASCT, yet the benefit of PI-based maintenance has not been demonstrated in a phase 3 trial vs placebo. Moreover, the feasibility of bortezomib maintenance in routine clinical practice is limited due to tolerability and the need for regular parenteral administration. There is a need for an oral PI maintenance therapy that can be administered for a prolonged period, improve depth of response without cumulative or late-onset toxicity, and improve convenience for patients. Methods The phase 3, double-blind, placebo-controlled, multicenter TOURMALINE-MM3 study (NCT02181413) compared weekly ixazomib vs placebo maintenance in NDMM patients who had at least a partial response (≥PR) to induction therapy with a PI and/or immunomodulatory drug (IMiD) followed by single ASCT. Patients were randomized (3:2) to receive ixazomib or matched placebo on days 1, 8, and 15 of 28-day cycles for up to 2 years or until progressive disease (PD) or unacceptable toxicity. Randomization was stratified by induction regimen (PI without IMiD vs IMiD without PI vs PI+IMiD), pre-induction ISS stage (I vs II or III), and post-ASCT response (complete response [CR] or very good partial response [VGPR] vs PR). Patients were ineligible if they had received post-ASCT consolidation or tandem ASCT. The ixazomib dose was 3.0 mg during cycles 1-4, increasing to 4 mg from cycle 5 if tolerated during cycles 1-4. The primary endpoint was PFS per independent review committee (IRC), who were blinded to treatment assignment. The key secondary endpoint was OS. Here, we report data from the final analysis for PFS (data cut-off: April 16, 2018). Results 656 patients were randomized (395 ixazomib; 261 placebo). Patient demographics were balanced between groups; overall median age was 57 years (range, 24-73), 37% vs 63% had ISS I vs II or III, 59%/11%/30% had received PI without IMiD / IMiD without PI / PI+IMiD induction therapy, 34%/45%/21% had achieved CR / VGPR / PR following induction/ASCT, and 18% had high-risk cytogenetics [del(17p), t(4;14), or t(14;16)]. After a median follow-up of 31 months with 54% of PFS events, there was a 28% reduction in the risk of progression/death, corresponding to a 39% improvement in PFS with ixazomib vs placebo (median 26.5 vs 21.3 months; hazard ratio [HR] 0.72; 95% CI: 0.582, 0.890; p=0.002; Figure). In a landmark analysis from ASCT, PFS was 30.7 vs 24.9 months (HR 0.684; 95% CI: 0.551, 0.848; p<0.001). Median PFS2 and OS have not yet been reached in either arm. Ixazomib maintenance led to higher rates of deepened response compared with placebo (relative risk 1.41; 95% CI: 1.10, 1.80; p=0.004). Conversion from documented MRD positivity at study entry to MRD negativity occurred at a higher rate with ixazomib compared with placebo (12% vs 7%). PFS benefit was seen broadly across subgroups, including ISS III (HR 0.661), PI-exposed (HR 0.750), PI-naïve (HR 0.497), and patients with high-risk cytogenetics (HR 0.625). Discontinuation due to AEs was low (7% ixazomib vs 5% placebo). With ixazomib vs placebo, 42% vs 26% of patients had grade ≥3 AEs; 27% vs 20% had serious AEs; and 1 patient vs 0 died on treatment. Common grade ≥3 AEs were infections (15% vs 8%) including pneumonia (6% vs 4%), gastrointestinal disorders (6% vs 1%), neutropenia (5% vs 3%), and thrombocytopenia (5% vs <1%). Peripheral neuropathy rates were 19% vs 15% (<1% vs 0 grade 3). Rate of second primary malignancies was 3% in both arms. Global Quality of Life scores (EORTC QLQ-C30) on ixazomib were similar to placebo. Conclusions This study demonstrated a 28% reduction in the risk of progression/death, corresponding to a 39% improvement in PFS with ixazomib maintenance, with deepening of responses and increased conversions to MRD negativity over control, as well as a favorable safety profile, including an absence of risk of second primary malignancies and low rates of peripheral neuropathy, supporting ixazomib as a valuable option for maintenance therapy in responding patients post-ASCT. Figure. Figure. Disclosures Dimopoulos: Janssen: Honoraria; Takeda: Honoraria; Amgen: Honoraria; Celgene: Honoraria; Bristol-Myers Squibb: Honoraria. Gay:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen Takeda Celgene, Amgen, BMS, and Roche: Other: Advisor; Janssen, Amgen, Takeda, Celgene, BMS: Honoraria; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy; Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees. Schjesvold:Oncopeptides: Consultancy; Abbvie: Honoraria; Novartis: Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Adaptive: Consultancy; Bayer: Consultancy; Bristol Myers Squibb: Consultancy; Takeda: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Research Funding. Beksac:Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen Cilag: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Deva: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Hajek:Amgen: Consultancy, Honoraria, Research Funding; Bristol Myers Squibb: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Novartis: Research Funding. Weisel:Amgen, BMS, Celgene, Janssen, and Takeda: Honoraria; Amgen, BMS, Celgene, Janssen, Juno, Sanofi, and Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen, Celgene, Janssen, and Sanofi: Research Funding. Goldschmidt:Novartis: Honoraria, Research Funding; Amgen: Consultancy, Research Funding; Adaptive Biotechnology: Consultancy; Sanofi: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Chugai: Honoraria, Research Funding; Bristol Myers Squibb: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; ArtTempi: Honoraria; Mundipharma: Research Funding. Maisnar:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria. Moreau:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees. Chng:Merck: Research Funding; Takeda: Consultancy, Honoraria, Other: Travel, accommodation, expenses; Amgen: Consultancy, Honoraria, Other: Travel, accommodation, expenses; Aslan: Research Funding; Janssen: Consultancy, Honoraria, Other: Travel, accommodation, expenses, Research Funding; Celgene: Consultancy, Honoraria, Other: Travel, accommodation, expenses, Research Funding. Kaiser:Janssen: Consultancy, Honoraria; Takeda: Consultancy, Other: Travel Support; Bristol-Myers Squibb: Consultancy, Other: Travel support; Chugai: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding. Zweegman:Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene Corp.: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding. Mateos:Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; GSK: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; GSK: Consultancy, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Spencer:Celgene: Honoraria, Research Funding, Speakers Bureau; Janssen-Cilag: Honoraria, Research Funding, Speakers Bureau; Amgen: Honoraria, Research Funding; BMS: Research Funding; Takeda: Honoraria, Research Funding, Speakers Bureau; STA: Honoraria. Iida:Janssen: Consultancy, Honoraria, Research Funding; Kyowa-Hakko Kirin: Research Funding; Bristol Myers Squibb: Honoraria, Research Funding; Astellas: Research Funding; Chugai: Research Funding; Novartis: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Ono: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Toyama Chemical: Research Funding; MSD: Research Funding; Gilead: Research Funding; Teijin Pharma: Research Funding; Sanofi: Consultancy. Morgan:Takeda: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Janssen: Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria. Teng:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Suryanarayan:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Skacel:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment; Department of Hematology, Charles University General Hospital, Prague, Czech Republic: Other: Affiliation. Dash:Takeda Pharmaceuticals International Co.: Employment. Labotka:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment.

Abstract Background Ixazomib, the first oral proteasome inhibitor (PI), is approved by the US FDA, in combination with lenalidomide-dexamethasone (Rd), for the treatment of pts who have received at least 1 prior therapy. Lenalidomide is a common partner agent in regimens for RRMM; however, due to increasing use of lenalidomide treatment to progression as a standard of care in the first-line setting, novel PI-based combinations without lenalidomide are needed for RRMM. Combinations of a PI, an alkylating agent, and dexamethasone have been shown to be active, with manageable side effects, in RRMM patients (e.g. VCD - bortezomib, cyclophosphamide, dexamethasone), but require SC or IV administration of the PI. The all-oral combination of ICd may offer activity, tolerability, and more convenient administration. This open-label, multicenter phase 2 study (NCT02046070) assessed the safety and efficacy of ICd in pts with RRMM. Methods Adult pts with RRMM after 1-3 prior lines of therapy, who had ECOG performance status 0-2, were not PI-refractory, had adequate hematologic, renal, cardiac, and hepatic function, and did not have grade ≥2 peripheral neuropathy (PN) or grade 1 PN with pain, were eligible. Pts received oral ixazomib 4.0 mg and oral cyclophosphamide 300 mg/m2 on days 1, 8, and 15, plus oral dexamethasone 40 mg (20 mg for pts aged &gt;75 yrs) on days 1, 8, 15, and 22, in 28-day cycles until disease progression or unacceptable toxicity. The primary endpoint was overall response rate (ORR; ≥partial response [PR]); secondary endpoints included safety, pharmacokinetics (PK), complete response (CR) plus very good PR (VGPR) rate, CR rate, time to response (TTR), duration of response (DOR), and progression-free survival (PFS). Results 78 pts were enrolled; median age was 64 yrs (40% aged &gt;65 yrs), 53% were male, median time from initial diagnosis was 53.4 months (range, 12.9-142.7), and 24%/27% had ISS stage II/III disease at diagnosis. Median number of prior therapies was 2, including prior bortezomib, lenalidomide, and stem cell transplant (SCT) in 45 (58%), 38 (49%), and 50 (64%) pts, respectively; 17% were immunomodulatory-drug-naive. At data cut-off (June 20, 2016), pts had received a median of 12 treatment cycles (range, 1-22). A total of 51 (65%) pts had discontinued treatment, primarily due to disease progression (26 pts, 33%) and AEs (13 pts, 17%). Overall, 92% of pts reported AEs, including 59% with grade ≥3 AEs (51%/71% in pts aged ≤65/&gt;65 yrs), and 29% with serious AEs (30%/29%). Common AEs are listed in Table 1. AEs resulted in dose reductions of any study drug in 28 (36%) pts (28%/48% of pts aged ≤65/&gt;65 yrs) and treatment discontinuation in 11 (14%) pts (15%/13% aged ≤65/&gt;65 yrs). Ixazomib, cyclophosphamide, and dexamethasone were dose modified in 83%, 85%, and 87% of pts, respectively. Median ixazomib relative dose intensity was 96%. There were 3 on-study deaths: cardiac arrest, severe pulmonary edema, and cerebral hemorrhage secondary to thrombocytopenia, with the latter considered treatment-related. PK data showed that ixazomib exposures were comparable to those in pts treated with IRd in the TOURMALINE-MM1 study, suggesting no PK interaction with Cd. ORR was 49%, including 16% CR+VGPR (Table 2); in pts with/without prior SCT, ORR was 41%/61% (15%/18% CR+VGPR). Median TTR in responding pts was 2.14 months; median DOR was not reached, with response durations of up to 17 months. After a median follow-up of 12.5 months, median PFS was not reached; 12-month PFS rate estimate was 57.5%. Subgroup analysis showed a higher ORR (68% vs 35%), a higher CR+VGPR rate (23% vs 12%), and a significant PFS improvement in pts aged &gt;65 yrs vs pts aged ≤65 yrs (12-month PFS rate estimate 67.2% vs 50.7%; HR=0.43, p=0.028) (Figure). Although pts aged &gt;65 yrs were less likely to have had prior SCT than those aged ≤65 yrs (22% vs 78%), this did not appear to account fully for the difference in outcomes (PFS in pts without vs with prior SCT, HR=0.82, p=0.6). Conclusions All-oral triplet therapy with ICd appears to have activity in RRMM pts, with a toxicity profile consistent with that seen with ixazomib in combination with Rd (Moreau, et al; N Engl J Med 2016). Preliminary best response and PFS data suggest there may be preferential benefit in elderly pts compared to younger patients (possibly related in part to more limited use of prior high-dose alkylator [melphalan] exposure associated with SCT in elderly pts) albeit with additional toxicity. Disclosures Kumar: Glycomimetics: Consultancy; Onyx: Consultancy, Research Funding; Kesios: Consultancy; Janssen: Consultancy, Research Funding; Sanofi: Consultancy, Research Funding; BMS: Consultancy; Millennium: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; AbbVie: Research Funding; Array BioPharma: Consultancy, Research Funding; Skyline: Honoraria, Membership on an entity's Board of Directors or advisory committees; Noxxon Pharma: Consultancy, Research Funding. Grzasko:Celgene: Honoraria; Munipharma: Honoraria; Janssen: Honoraria. Jędrzejczak:Novartis: Consultancy, Research Funding; BMS: Research Funding; Janssen-Cilag: Consultancy; Celgene: Consultancy; Angelini: Consultancy; Roche: Consultancy, Research Funding; Amgen: Research Funding; Sandoz: Consultancy. Kyrtsonis:Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genesis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees. Gupta:Millennium Pharmaceuticals Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Teng:Millennium Pharmaceuticals Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment; AMAG Pharmaceuticals: Equity Ownership; Gilead Science: Equity Ownership; Array: Equity Ownership. Byrne:Millennium Pharmaceuticals Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Labotka:Millennium Pharmaceuticals Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Dimopoulos:Genesis: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees.

Background:Deepened response has been associated with prolonged progression‐free (PFS) and overall survival in multiple myeloma, including in the maintenance therapy setting. In the Myeloma XI trial, post‐ASCT maintenance with lenalidomide vs observation resulted in improved responses in 15.8% vs 11.0% of patients (pts) and a median PFS of 56.9 vs 30.1 months (Jackson et al, ASH 2017). In the phase 3, double‐blind, placebo‐controlled TOURMALINE‐MM3 study (NCT02181413), post‐ASCT maintenance therapy with the oral proteasome inhibitor (PI) ixazomib vs placebo resulted in a 39% improvement in PFS (median 26.5 vs 21.3 months; HR 0.72; 95% CI: 0.58–0.89; p = 0.002), with a favorable safety profile (Dimopoulos et al, Lancet 2019). We report improvements in depth of response and the impact on outcomes in TOURMALINE‐MM3.Aims:To evaluate the rates and timing of response improvement during ixazomib vs placebo maintenance and the impact on PFS in TOURMALINE‐MM3.Methods:Pts who had achieved ≥partial response (PR) to induction therapy with a PI and/or immunomodulatory drug followed by single ASCT were randomized 3:2 to receive ixazomib (N = 395) or placebo (N = 261) on day 1, 8, and 15 of 28‐d cycles for up to 2 years or until progressive disease or unacceptable toxicity. Randomization was stratified by induction regimen, pre‐induction ISS stage, and post‐ASCT response (complete response [CR] or very good PR [VGPR] vs PR). Ixazomib dose was 3 mg in cycles 1–4 and 4 mg from cycle 5 if tolerated in cycles 1–4. Minimal residual disease (MRD) was assessed at screening by flow cytometry (10–5 sensitivity). The primary endpoint was PFS per independent review committee (IRC). Other endpoints included rate of response improvement in pts enrolled in VGPR or PR.Results:At study entry, 60 (15%), 213 (54%), and 89 (23%) pts in the ixazomib arm and 54 (21%), 152 (58%), and 35 (13%) in the placebo arm had CR, VGPR, and PR, respectively, by IRC. Deepening responses were seen in 139/302 (46%) ixazomib vs 60/187 (32%) placebo pts with VGPR/PR at enrollment (relative risk [RR] 1.41, 95% CI 1.1–1.8, p = 0.004), including 92/213 (43%) vs 48/152 (32%) VGPR to CR (RR 1.37, p = 0.025) and 47/89 (53%) vs 12/35 (34%) PR to VGPR/CR (RR 1.54, p = 0.063). On Kaplan‐Meier analysis of time to best deepened response in VGPR/PR pts (Figure), 24‐month rates of deepening response were 54.2% vs 41.4%, and there was a 38.4% improvement in the chance of deepening response over time with ixazomib vs placebo (HR 1.384, p = 0.034). A pooled analysis across arms among pts enrolled in VGPR/PR showed that deepening response vs no improvement was associated with prolonged PFS (median not reached vs 15.9 months; HR 0.245, 95% CI 0.184–0.325, p < 0.0001). Analysis by treatment arm showed that, in VGPR/PR pts with deepening response, 24‐month PFS rates were 77.4% vs 68.3% with ixazomib vs placebo (medians not reached; HR 0.875; 12.5% risk reduction; 95% CI 0.52–1.47; p = 0.615); in VGPR/PR pts without deepening response 24‐month PFS rates were 33.4% vs 23.6% (median 17.9 vs 14.1 months; HR 0.780; 22% risk reduction; 95% CI 0.59–1.03; p = 0.080). Baseline MRD status was a strong predictor of deepening response; deepening responses were seen in 63% (78/124) vs 32% (94/293) of MRD‐ vs MRD+ pts enrolled in VGPR/PR.Summary/Conclusion:Post‐ASCT maintenance with ixazomib resulted in a significantly higher rate of deepening response vs placebo; deepening response was associated with prolonged PFS. Ixazomib resulted in non‐significant PFS benefit vs placebo in VGPR/PR pts with and without deepening response; prolonged follow‐up would be needed to confirm these results.image

AbstractObjectivesTo evaluate the safety and efficacy of maintenance therapy with the oral proteasome inhibitor ixazomib in patients with newly diagnosed multiple myeloma (NDMM) not undergoing transplantation.MethodsData were pooled from four NDMM phase I/II studies; patients received induction therapy with once‐ or twice‐weekly ixazomib plus lenalidomide‐dexamethasone (IRd), melphalan‐prednisone (IMP), or cyclophosphamide‐dexamethasone (ICd), followed by single‐agent ixazomib maintenance, given at the last tolerated dose during induction, until disease progression, death, or unacceptable toxicity.ResultsA total of 121 patients achieved stable disease or better after induction (weekly IRd, n = 25; twice‐weekly IRd, n = 18; weekly or twice‐weekly IMP, n = 35; weekly ICd, n = 43) and received ≥ 1 dose of ixazomib maintenance. Grade ≥ 3 drug‐related adverse events occurred in 24% of patients during maintenance; each event was reported in ≤2% of patients. Rates of complete response were 22% after induction and 35% after maintenance. A total of 28 patients (23%) improved their response during maintenance.ConclusionsIxazomib maintenance following ixazomib‐based induction is associated with deepening of responses and a positive safety profile with no cumulative toxicity in patients with NDMM not undergoing transplantation, suggesting that ixazomib is feasible for long‐term administration. Phase III investigation of ixazomib maintenance is ongoing.

SummaryThere is a need for efficacious, convenient treatments with long‐term tolerability for patients with relapsed/refractory multiple myeloma (RRMM). This phase 2 study evaluated the all‐oral combination of ixazomib, cyclophosphamide and dexamethasone (ICd). Patients with RRMM received ixazomib 4 mg and cyclophosphamide 300 mg/m2 on days 1, 8 and 15, and dexamethasone 40 mg on days 1, 8, 15 and 22 in 28‐day cycles. The primary endpoint was overall response rate (ORR). Seventy‐eight patients were enrolled (median age 63·5 years). At data cut‐off, patients had received a median of 12 treatment cycles; 31% remained on treatment. ORR was 48% [16% very good partial response or better (≥VGPR)]. ORR was 64% and 32% in patients aged ≥65 and <65 years (25% and 16% ≥VGPR), respectively. At a median follow‐up of 15·2 months, median progression‐free survival (PFS) was 14·2 months, with a trend towards better PFS in patients aged ≥65 years vs. <65 years (median 18·7 months vs. 12·0 months; hazard ratio 0·62, P = 0·14). ICd was well tolerated. The most common treatment‐emergent adverse events were diarrhoea (33%), nausea (24%), upper respiratory tract infection (24%), and thrombocytopenia (22%); 10 patients (13%) had peripheral neuropathy (one grade 3). This study is registered at ClinicalTrials.gov (NCT02046070).