Minimal residual disease in Myeloma: Application for clinical care and new drug registration

The development of novel agents has transformed the treatment paradigm for multiple myeloma, with minimal residual disease (MRD) negativity now achievable across the entire disease spectrum. Bone marrow–based technologies to assess MRD, including approaches using next-generation flow and next-generation sequencing, have provided real-time clinical tools for the sensitive detection and monitoring of MRD in patients with multiple myeloma. Complementary liquid biopsy–based assays are now quickly progressing with some, such as mass spectrometry methods, being very close to clinical use, while others utilizing nucleic acid–based technologies are still developing and will prove important to further our understanding of the biology of MRD. On the regulatory front, multiple retrospective individual patient and clinical trial level meta-analyses have already shown and will continue to assess the potential of MRD as a surrogate for patient outcome. Given all this progress, it is not surprising that a number of clinicians are now considering using MRD to inform real-world clinical care of patients across the spectrum from smoldering myeloma to relapsed refractory multiple myeloma, with each disease setting presenting key challenges and questions that will need to be addressed through clinical trials. The pace of advances in targeted and immune therapies in multiple myeloma is unprecedented, and novel MRD-driven biomarker strategies are essential to accelerate innovative clinical trials leading to regulatory approval of novel treatments and continued improvement in patient outcomes

A murine model of CML blast crisis induced by cooperation between BCR/ABL and NUP98/HOXA9.

Constitutive activation of tyrosine kinases, such as the BCR/ABL fusion associated with t(9;22)(q34;q22), is a hallmark of chronic myeloid leukemia (CML) syndromes in humans. Expression of BCR/ABL is both necessary and sufficient to cause a chronic myeloproliferative syndrome in murine bone marrow transplantation models, and absolutely depends on kinase activity. Progression of CML to acute leukemia (blast crisis) in humans has been associated with acquisition of secondary chromosomal translocations, including the t(7;11)(p15;p15) resulting in the NUP98/HOXA9 fusion protein. We demonstrate that BCR/ABL cooperates with NUP98/HOXA9 to cause blast crisis in a murine model. The phenotype depends both on expression of BCR/ABL and NUP98/HOXA9, but tumors retain sensitivity to the ABL inhibitor STI571 in vitro and in vivo. This paradigm is applicable to other constitutively activated tyrosine kinases such as TEL/PDGFbetaR. These experiments document cooperative effects between constitutively activated tyrosine kinases, which confer proliferative and survival properties to hematopoietic cells, with mutations that impair differentiation, such as the NUP98/HOXA9, giving rise to the acute myeloid leukemia (AML) phenotype. Furthermore, these data indicate that despite acquisition of additional mutations, CML blast crisis cells retain their dependence on BCR/ABL for proliferation and survival

A pooled analysis of outcomes according to cytogenetic abnormalities in patients receiving ixazomib- vs placebo-based therapy for multiple myeloma

Abstract Some cytogenetic abnormalities (CAs) are associated with poorer prognosis in multiple myeloma (MM); proteasome inhibitors appear to benefit patients with high-risk CAs. We evaluated 2247 MM patients from the TOURMALINE-MM1/-MM2/-MM3/-MM4 trials to assess the PFS benefit of ixazomib plus lenalidomide-dexamethasone (Rd) vs placebo-Rd (TOURMALINE-MM1/-MM2) or ixazomib vs placebo (TOURMALINE-MM3/-MM4) in specific high-risk CAs. After a pooled median follow-up of 25.6 months, the hazard ratio (HR) for PFS with ixazomib- vs placebo-based therapy for high-risk patients was 0.74 (95% confidence interval [CI]: 0.59–0.93; median PFS [mPFS] 17.8 vs 13.2 months), and 0.70 (95% CI: 0.62–0.80; mPFS 26.3 vs 17.6 months) for complementary standard-risk patients. The HR for expanded high-risk patients was 0.75 (95% CI: 0.64–0.87; mPFS 18.1 vs 14.1 months), and 0.71 (95% CI: 0.59–0.85; mPFS 36.1 vs 21.4 months) for complementary standard-risk patients. The HR for PFS with ixazomib- vs placebo-based therapy was 0.68 in patients with t(4;14) (95% CI: 0.48–0.96; mPFS 22.4 vs 13.2 months), and 0.77 for patients with amp1q21 (95% CI: 0.63–0.93; mPFS 18.8 vs 14.5 months). A PFS benefit was demonstrated with ixazomib- vs placebo-based therapy regardless of cytogenetic status, with greatest benefit observed in patients with t(4;14) and amp1q21

MRD dynamics during maintenance for improved prognostication of 1280 patients with myeloma in the TOURMALINE-MM3 and -MM4 trials

Measurable residual disease (MRD) evaluation may help to guide treatment duration in multiple myeloma (MM). Paradoxically, limited longitudinal data exist on MRD during maintenance. We investigated the prognostic value of MRD dynamics in 1280 transplant-eligible and -ineligible patients from the TOURMALINE-MM3 and -MM4 randomized placebo-controlled phase 3 studies of 2-year ixazomib maintenance. MRD status at randomization showed independent prognostic value (median progression-free survival [PFS], 38.6 vs 15.6 months in MRD− vs MRD+ patients; HR, 0.47). However, MRD dynamics during maintenance provided more detailed risk stratification. A 14-month landmark analysis showed prolonged PFS in patients converting from MRD+ to MRD− status vs those with persistent MRD+ status (76.8% vs 27.6% 2-year PFS rates). Prolonged PFS was observed in patients with sustained MRD− status vs those converting from MRD− to MRD+ status (75.0% vs 34.2% 2-year PFS rates). Similar results were observed at a 28-month landmark analysis. Ixazomib maintenance vs placebo improved PFS in patients who were MRD+ at randomization (median, 18.8 vs 11.6 months; HR, 0.65) or at the 14-month landmark (median, 16.8 vs 10.6 months; HR, 0.65); no difference was observed in patients who were MRD−. This is the largest MM population undergoing yearly MRD evaluation during maintenance reported to date. We demonstrate the limited prognostic value of a single–time point MRD evaluation, because MRD dynamics over time substantially impact PFS risk. These findings support MRD− status as a relevant end point during maintenance and confirm the increased progression risk in patients converting to MRD+ from MRD− status. These trials were registered at www.clinicaltrials.gov as #NCT02181413 and #NCT02312258

A Phase 1 First-in-Human Study of the Anti-CD38 Dimeric Fusion Protein TAK-169 for the Treatment of Patients (pts) with Relapsed or Refractory Multiple Myeloma (RRMM) Who Are Proteasome Inhibitor (PI)- and Immunomodulatory Drug (IMiD)-Refractory, Including Pts Relapsed/Refractory (R/R) or Naïve to Daratumumab (dara)

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 subuni

Double-Negative T Cell Levels Correlate with Chronic Graft-versus-Host Disease Severity

Chronic graft-versus-host disease (cGVHD) is a major complication, affecting 50% to 80% of long-term survivors of allogeneic hematopoietic stem cell transplantation. Current cGVHD therapies are neither specific nor curative, and patients are typically maintained for several months to years under immunosuppressive regimens that are associated with important side effects and increased susceptibility to life-threatening infections. As a result, continued investigation into the pathology of the disease and the search for novel diagnostic and therapeutic strategies to treat cGVHD remains a high priority. We report that the cellular dynamics of various immune cell subsets are related to cGVHD onset and severity in a cohort of allogeneic hematopoietic stem cell transplantation recipients. We document a decrease in the proportion of CD45RO + CD4 −CD8 − (double-negative [DN]) T cells at the onset of cGVHD, a time at which serum levels of B cell activating factor and B cells are increased. We also find that DN T cell levels are correlated with cGVHD severity. Our present findings are in line with the view that activated DN T cells exhibit their immunoregulatory potential by eliminating B cells in vivo. Taken together, these findings suggest that maintaining elevated DN T cell numbers before the onset of cGVHD may prevent pathological B cell responses

EVIDENCE meta-analysis: evaluating minimal residual disease as an intermediate clinical endpoint for multiple myeloma

Estimating progression-free survival (PFS) and overall survival (OS) superiority during clinical trials of multiple myeloma (MM) has become increasingly challenging as novel therapeutics have improved patient outcomes. Thus, it is imperative to identify earlier endpoint surrogates that are predictive of long-term clinical benefit to expedite development of more effective therapies. Minimal residual disease (MRD)-negativity is a common intermediate endpoint that has shown prognostic value for clinical benefit in trials of patients with multiple myeloma (MM). This meta-analysis was based on the FDA guidance for considerations for a meta-analysis of MRD as a clinical endpoint and evaluates MRD-negativity as an early endpoint reasonably likely to predict long-term clinical benefit. Eligible studies were phase 2 or 3 randomized controlled clinical trials measuring MRD negativity as an endpoint in patients with MM, with follow-up of ≥6 months following an a priori defined time point of 12±3 months post-randomization. Eight newly diagnosed MM-(NDMM)-studies evaluating 4,907 patients were included. Trial-level associations between MRD-negativity and PFS were R2WLSiv (95% CI) 0.67 (0.43-0.91) and R2copula 0.84 (0.64->0.99) at the 12-month timepoint. The individual-level association between 12-month MRD negativity and PFS resulted in a global odds ratio of 4.02 (95% CI: 2.57-5.46). For relapse/refractory MM-(RRMM), there were four studies included, and the individual-level association between 12-month MRD negativity and PFS resulted in a global odds ratio of 7.67 (4.24-11.10). A clinical trial demonstrating a treatment effect on MRD is reasonably likely to eventually demonstrate a treatment effect on PFS, suggesting that MRD may be an early clinical endpoint reasonably likely to predict clinical benefit in MM, that may be used to support accelerated approval and thereby expedite the availability of new drugs to patients with MM