First-in-Human, Single- and Multiple-Ascending-Dose Studies in Healthy Subjects to Assess Pharmacokinetics, Pharmacodynamics, and Safety/Tolerability of Iberdomide, a Novel Cereblon E3 Ligase Modulator

Degradation of IKZF1 prevents epigenetic progression of T cell exhaustion in an antigen-specific assay

In cancer, chronic antigen stimulation drives effector T cells to exhaustion, limiting the efficacy of T cell therapies. Recent studies have demonstrated that epigenetic rewiring governs the transition of T cells from effector to exhausted states and makes a subset of exhausted T cells non-responsive to PD1 checkpoint blockade. Here, we describe an antigen-specific assay for T cell exhaustion that generates T cells phenotypically and transcriptionally similar to those found in human tumors. We perform a screen of human epigenetic regulators, identifying IKZF1 as a driver of T cell exhaustion. We determine that the IKZF1 degrader iberdomide prevents exhaustion by blocking chromatin remodeling at T cell effector enhancers and preserving the binding of AP-1, NF-κB, and NFAT. Thus, our study uncovers a role for IKZF1 as a driver of T cell exhaustion through epigenetic modulation, providing a rationale for the use of iberdomide in solid tumors to prevent T cell exhaustion.

Targeting Ikaros and Aiolos: reviewing novel protein degraders for the treatment of multiple myeloma, with a focus on iberdomide and mezigdomide

INTRODUCTION

The treatment of multiple myeloma (MM) is evolving rapidly. Quadruplet regimens incorporating proteasome inhibitors, immunomodulatory drugs (IMiDs), and CD38 monoclonal antibodies have emerged as standard-of-care options for newly diagnosed MM, and numerous novel therapies have been approved for relapsed/refractory MM. However, there remains a need for novel options in multiple settings, including refractoriness to frontline standards of care.

AREAS COVERED

Targeting degradation of IKZF1 and IKZF3 - Ikaros and Aiolos - through modulation of cereblon, an E3 ligase substrate recruiter/receptor, is a key mechanism of action of the IMiDs and the CELMoD agents. Two CELMoD agents, iberdomide and mezigdomide, have demonstrated substantial preclinical and clinical activity in MM and have entered phase 3 investigation. Using a literature search methodology comprising searches of PubMed (unlimited time-frame) and international hematology/oncology conference abstracts (2019-2023), this paper reviews the importance of Ikaros and Aiolos in MM, the mechanism of action of the IMiDs and CELMoD agents and their relative potency for targeting Ikaros and Aiolos, and preclinical and clinical data on iberdomide and mezigdomide.

EXPERT OPINION

Emerging data suggest that iberdomide and mezigdomide have promising activity, including in IMiD-resistant settings and, pending phase 3 findings, may provide additional treatment options for patients with MM.

A Phase I, Open-Label, Mass Balance Study of [14C]-Iberdomide in Healthy Subjects

BACKGROUND

Iberdomide is a novel potent cereblon modulator (CELMoD®) agent, which is currently under clinical development for hematological malignancies. A human mass balance study was conducted to characterize the biotransformation and excretion pathways of iberdomide.

METHOD

After a single dose of radiolabelled [14C]-iberdomide (1 mg) in six healthy subjects. Blood, urine, and fecal samples were collected for pharmacokinetics, mass balance, and clinical laboratory assessments.

RESULTS

Results showed that a single oral dose of 1 mg iberdomide was generally well tolerated in healthy subjects. The recovery of [14C]-iberdomide-derived radioactivity in humans was 45.9% in urine and 42.6% in feces. Based on exposure (area under the concentration-time curve [AUC0-24]), iberdomide and M12 (metabolites) accounted for approximately 59% and 14% of circulating total radioactivity (TRA) exposure, respectively. Of the 88.5% TRA excreted, approximately 27% was excreted as unchanged iberdomide and 62% as metabolites, with similar amounts of excreted metabolites in the urine (16%) and feces (11%).

CONCLUSION

Biotransformation of iberdomide in humans included multiple oxidations of the morpholino moiety as well as glutarimide ring hydrolysis of parent and oxidized metabolites and a combination of these pathways. Iberdomide was the predominant component in human plasma, with metabolite M12 being the most prominent circulating metabolite. In excreta, similar iberdomide-derived radioactivity was found in urine and feces.

TRIAL REGISTRATION NUMBER

NCT03294603.

Human and mouse early B cell development: So similar but so different

Early B cell development in the bone marrow ensures the replenishment of the peripheral B cell pool. Immature B cells continuously develop from hematopoietic stem cells, in a process guided by an intricate network of transcription factors as well as chemokine and cytokine signals. Humans and mice possess somewhat similar regulatory mechanisms of B lymphopoiesis. The continuous discovery of monogenetic defects that impact early B cell development in humans substantiates the similarities and differences with B cell development in mice. These differences become relevant when targeted therapeutic approaches are used in patients; therefore, predicting potential immunological adverse events is crucial. In this review, we have provided a phenotypical classification of human and murine early progenitors and B cell stages, based on surface and intracellular protein expression. Further, we have critically compared the role of key transcription factors (Ikaros, E2A, EBF1, PAX5, and Aiolos) and chemo- or cytokine signals (FLT3, c-kit, IL-7R, and CXCR4) during homeostatic and aberrant B lymphopoiesis in both humans and mice.

Exposure-Response Analysis to Assess the Concentration-QTc Relationship of Iberdomide

Iberdomide is an orally available cereblon-modulating agent being developed for the treatment of hematologic malignancies and autoimmune-mediated diseases. To assess the potential concentration-QTc relationship in humans and to ascertain or exclude a potential QT effect by iberdomide, a plasma concentration and ΔQTcF (change from baseline of corrected QT interval using the Fridericia formula) model of iberdomide was developed. Iberdomide concentration and paired high-quality, intensive electrocardiogram signal from a single-ascending-dose study in healthy subjects (N = 56) were included in the analysis. The primary analysis was based on a linear mixed-effect model with ΔQTcF as the dependent variable; iberdomide plasma concentration and baseline QTcF as continuous covariates; treatment (active or placebo) and time as a categorical factor; and a random intercept per subject. The predicted change from baseline and placebo corrected (ΔΔQTcF) at the observed geometric mean maximum plasma concentration and 2-sided 90% confidence intervals at different dose levels were calculated. The upper bound of the 90% confidence interval of the model-predicted ΔΔQTcF effect at maximum concentration from the supratherapeutic dose of 6 mg (2.54 milliseconds) is <10-millisecond threshold, suggesting that iberdomide does not have a clinically relevant QT prolongation liability.

iTAG an optimized IMiD-induced degron for targeted protein degradation in human and murine cells

To address the limitation associated with degron based systems, we have developed iTAG, a synthetic tag based on IMiDs/CELMoDs mechanism of action that improves and addresses the limitations of both PROTAC and previous IMiDs/CeLMoDs based tags. Using structural and sequence analysis, we systematically explored native and chimeric degron containing domains (DCDs) and evaluated their ability to induce degradation. We identified the optimal chimeric iTAG(DCD23 60aa) that elicits robust degradation of targets across cell types and subcellular localizations without exhibiting the well documented "hook effect" of PROTAC-based systems. We showed that iTAG can also induce target degradation by murine CRBN and enabled the exploration of natural neo-substrates that can be degraded by murine CRBN. Hence, the iTAG system constitutes a versatile tool to degrade targets across the human and murine proteome.

A Phase 1, Multicenter, Open-Label Study to Evaluate the Pharmacokinetics of Iberdomide in Subjects with Mild, Moderate, or Severe Hepatic Impairment Compared with Healthy Subjects

Introduction

Iberdomide, a novel cereblon modulator (CELMoD^®), is currently under clinical investigation for hematology indications. To evaluate the influence of hepatic impairment on the pharmacokinetics (PK) of iberdomide and its major active metabolite M12, a phase 1, multicenter, open-label study was conducted in healthy subjects and subjects with mild, moderate, and severe hepatic impairment.

Methods

Forty subjects were enrolled in the study and divided into five groups based on hepatic function. 1 mg iberdomide was administered and plasma samples were collected to evaluate the pharmacokinetics of iberdomide and M12.

Results

After a single dose of iberdomide (1 mg), mean iberdomide Cmax (maximum observed concentration) and AUC (area under the concentration-time curve) exposure were generally comparable between hepatic impairment (HI) subjects (severe, moderate and mild) and their respective matched normal controls. Mean Cmax and AUC exposure of the metabolite M12 were generally comparable between mild HI and matched normal subjects. However, mean Cmax of the M12 was 30% and 65% lower and AUC was 57% and 63% lower in moderate and severe HI subjects as compared to their respective matched normal controls. However, given the relatively low M12 exposure as compared to its parent drug, the observed differences were not considered clinically meaningful.

Conclusion

In summary, 1 mg single oral dose of iberdomide was generally well-tolerated. HI (mild, moderate or severe) had no clinically relevant impact on iberdomide PK and therefore, no dose adjustment is warranted.

Model-based analysis for the population pharmacokinetics of iberdomide and its major active metabolite in healthy subjects and patients with relapsed and refractory multiple myeloma

AIMS

A parent-metabolite population pharmacokinetic (popPK) model of iberdomide and its pharmacologically active metabolite (M12) was developed and the influence of demographic and disease-related covariates on popPK parameters was assessed based on data from 3 clinical studies of iberdomide (dose range, 0.1-6 mg) in healthy subjects (n = 81) and patients with relapsed and refractory multiple myeloma (n 245).

METHODS

Nonlinear mixed effects modelling was used to develop the popPK model based on data from 326 subjects across 3 clinical studies.

RESULTS

The pharmacokinetics (PK) of iberdomide were adequately described with a 2-compartment model with first-order absorption and elimination. A first-order conversion rate was used to link the 1-compartment linear elimination metabolite model with the parent model. Subject type (multiple myeloma patients vs. healthy subject) was a statistically significant covariate on apparent clearance and apparent volume of distribution for the central compartment, suggesting different PK between patients with multiple myeloma and healthy subjects. Aspartate aminotransferase and sex were statistically but not clinically relevant covariates on apparent clearance. Metabolite (M12) PK tracked the PK of iberdomide. The metabolite to parent ratio was consistent across doses and combinations.

CONCLUSION

The parent-metabolite population PK model adequately described the time course PK data of iberdomide and M12. Iberdomide and M12 PK exposure were not complicated by demographic factors (age [19-82 y], body weight [41-172 kg], body surface area [1.4-2.7 m² ], body mass index [16.4-59.3 kg/m² ]), combination (in combination with dexamethasone and daratumumab), mild hepatic, or mild and moderate renal impairments. The model can be used to guide the dosing strategy for special patient population and inform future iberdomide study design.

Targeting cereblon in hematologic malignancies

The protein cereblon (CRBN) is a substrate receptor of the cullin 4-really interesting new gene (RING) E3 ubiquitin ligase complex CRL4^CRBN. Targeting CRBN mediates selective protein ubiquitination and subsequent degradation via the proteasome. This review describes novel thalidomide analogs, immunomodulatory drugs, also known as CRBN E3 ubiquitin ligase modulators or molecular glues (avadomide, iberdomide, CC-885, CC-90009, BTX-1188, CC-92480, CC-99282, CFT7455, and CC-91633), and CRBN-based proteolysis targeting chimeras (PROTACs) with increased efficacy and potent activity for application in hematologic malignancies. Both types of CRBN-binding drugs, molecular glues, and PROTACs stimulate the interaction between CRBN and its neosubstrates, recruiting target disease-promoting proteins and the E3 ubiquitin ligase CRL4^CRBN. Proteins that are traditionally difficult to target (transcription factors and oncoproteins) can be polyubiquitinated and degraded in this way. The competition of CRBN neosubstrates with endogenous CRBN-interacting proteins and the pharmacology and rational combination therapies of and mechanisms of resistance to CRL4^CRBN modulators or CRBN-based PROTACs are described.

Mechanism of immunomodulatory drug resistance and novel therapeutic strategies in multiple myeloma

OBJECTIVE

The mechanism of immunomodulatory drugs (IMiDs) resistance to multiple myeloma (MM) cells has been gradually demonstrated by recently studies, and some potential novel strategies have been confirmed to have antimyeloma activity and be associated with IMiD activity in MM.

METHODS

This article searched the Pubmed library, reviewed some recently studies related to IMiD resistance to MM cells and summarized some potent agents to improve IMiD resistance to MM cells.

RESULTS

Studies have confirmed that cereblon is a primary direct protein target of IMiDs. IRF4 not only is affected by the IKZF protein but also can directly inhibit the expression of BMF and BIM, thereby promoting the survival of MM cells. Additionally, the expression of IRF4 and MYC also plays an important role in three important signaling pathways (Wnt, STAT3 and MAPK/ERK) related to IMiD resistance. Notably, MYC, a downstream factor of IRF4, may be upregulated by BRD4, and upregulation of MYC promotes cell proliferation in MM and disease progression. Recently, some novel therapeutic agents targeting BRD4, a histone modification-related 'reader' of epigenetic marks, or other important factors (e.g. TAK1) in relevant signaling pathways have been developed and they may provide new options for relapse/refractory MM therapy, such as BET inhibitors, CBP/EP300 inhibitors, dual-target BET-CBP/EP300 inhibitors, TAK1 inhibitors, and they may provide new options for relapsed/refractory MM therapy.

CONCLUSIONS

Accumulated studies have revealed that some key factors associated with the mechanism of IMiD resistance to MM cells. Some agents represent promising new therapeutics of MM to regulate the IRF4/MYC axis by inhibiting BRD4 expression or signaling pathway activation.

Lenalidomide promotes the development of TP53-mutated therapy-related myeloid neoplasms

There is a growing body of evidence that therapy-related myeloid neoplasms (t-MNs) with driver gene mutations arise in the background of clonal hematopoiesis (CH) under the positive selective pressure of chemo- and radiation therapies. Uncovering the exposure relationships that provide selective advantage to specific CH mutations is critical to understanding the pathogenesis and etiology of t-MNs. In a systematic analysis of 416 patients with t-MN and detailed prior exposure history, we found that TP53 mutations were significantly associated with prior treatment with thalidomide analogs, specifically lenalidomide. We demonstrated experimentally that lenalidomide treatment provides a selective advantage to Trp53-mutant hematopoietic stem and progenitor cells (HSPCs) in vitro and in vivo, the effect of which was specific to Trp53-mutant HSPCs and was not observed in HSPCs with other CH mutations. Because of the differences in CK1α degradation, pomalidomide treatment did not provide an equivalent level of selective advantage to Trp53-mutant HSPCs, providing a biological rationale for its use in patients at high risk for t-MN. These findings highlight the role of lenalidomide treatment in promoting TP53-mutated t-MNs and offer a potential alternative strategy to mitigate the risk of t-MN development.

Melflufen for the treatment of multiple myeloma

INTRODUCTION

Melphalan flufenamide (melflufen) is a first-in-class peptide-drug conjugate that takes advantage of increased aminopeptidase activity inside tumor cells to rapidly release alkylating agents therein. Melflufen in combination with dexamethasone has been evaluated in multiple clinical trials in patients with relapsed/refractory multiple myeloma (MM).

AREAS COVERED

This profile covers the unique mechanism of action of melflufen, the preclinical results supporting its activity in cellular models of resistance to chemotherapy, its activity in animal models of MM, and the clinical pharmacokinetics of melflufen. Findings from clinical trials evaluating melflufen, including the pivotal phase II HORIZON study and the phase III OCEAN study, are discussed.

EXPERT OPINION

Although MM treatment has improved, patients with disease refractory to multiple standard-of-care drug classes face a dismal prognosis. Melflufen demonstrated efficacy and tolerability in select populations, with an initial approval in the United States in patients with ≥ four previous lines of therapy and triple-class-refractory MM. Results from the phase III OCEAN study - currently under discussion with regulatory agencies in the United States and Europe - are more complex and have been put into context herein. Lastly, melflufen provides a proof-of-concept for the utility of the peptide-drug conjugate platform in relapsed/refractory MM.

2021 White Paper on Recent Issues in Bioanalysis: Mass Spec of Proteins, Extracellular Vesicles, CRISPR, Chiral Assays, Oligos; Nanomedicines Bioanalysis; ICH M10 Section 7.1; Non-Liquid & Rare Matrices; Regulatory Inputs (Part 1A - Recommendations on Endogenous Compounds, Small Molecules, Complex Methods, Regulated Mass Spec of Large Molecules, Small Molecule, PoC & Part 1B - Regulatory Agencies' Inputs on Bioanalysis, Biomarkers, Immunogenicity, Gene & Cell Therapy and Vaccine)

The 15th edition of the Workshop on Recent Issues in Bioanalysis (15th WRIB) was held on 27 September to 1 October 2021. Even with a last-minute move from in-person to virtual, an overwhelmingly high number of nearly 900 professionals representing pharma and biotech companies, contract research organizations (CROs), and multiple regulatory agencies still eagerly convened to actively discuss the most current topics of interest in bioanalysis. The 15th WRIB included 3 Main Workshops and 7 Specialized Workshops that together spanned 1 week in order to allow exhaustive and thorough coverage of all major issues in bioanalysis, biomarkers, immunogenicity, gene therapy, cell therapy and vaccines. Moreover, in-depth workshops on biomarker assay development and validation (BAV) (focused on clarifying the confusion created by the increased use of the term "Context of Use - COU"); mass spectrometry of proteins (therapeutic, biomarker and transgene); state-of-the-art cytometry innovation and validation; and, critical reagent and positive control generation were the special features of the 15th edition. This 2021 White Paper encompasses recommendations emerging from the extensive discussions held during the workshop, and is aimed to provide the bioanalytical community with key information and practical solutions on topics and issues addressed, in an effort to enable advances in scientific excellence, improved quality and better regulatory compliance. Due to its length, the 2021 edition of this comprehensive White Paper has been divided into three parts for editorial reasons. This publication (Part 1A) covers the recommendations on Endogenous Compounds, Small Molecules, Complex Methods, Regulated Mass Spec of Large Molecules, Small Molecule, PoC. Part 1B covers the Regulatory Agencies' Inputs on Bioanalysis, Biomarkers, Immunogenicity, Gene & Cell Therapy and Vaccine. Part 2 (ISR for Biomarkers, Liquid Biopsies, Spectral Cytometry, Inhalation/Oral & Multispecific Biotherapeutics, Accuracy/LLOQ for Flow Cytometry) and Part 3 (TAb/NAb, Viral Vector CDx, Shedding Assays; CRISPR/Cas9 & CAR-T Immunogenicity; PCR & Vaccine Assay Performance; ADA Assay Comparabil ity & Cut Point Appropriateness) are published in volume 14 of Bioanalysis, issues 10 and 11 (2022), respectively.

Biological impact of iberdomide in patients with active systemic lupus erythematosus

OBJECTIVES

Iberdomide is a high-affinity cereblon ligand that promotes proteasomal degradation of transcription factors Ikaros (IKZF1) and Aiolos (IKZF3). Pharmacodynamics and pharmacokinetics of oral iberdomide were evaluated in a phase 2b study of patients with active systemic lupus erythematosus (SLE).

METHODS

Adults with autoantibody-positive SLE were randomised to placebo (n=83) or once daily iberdomide 0.15 mg (n=42), 0.3 mg (n=82) or 0.45 mg (n=81). Pharmacodynamic changes in whole blood leucocytes were measured by flow cytometry, regulatory T cells (Tregs) by epigenetic assay, plasma cytokines by ultrasensitive cytokine assay and gene expression by Modular Immune Profiling.

RESULTS

Iberdomide exhibited linear pharmacokinetics and dose-dependently modulated leucocytes and cytokines. Compared with placebo at week 24, iberdomide 0.45 mg significantly (p<0.001) reduced B cells, including those expressing CD268 (TNFRSF13C) (-58.3%), and plasmacytoid dendritic cells (-73.9%), and increased Tregs (+104.9%) and interleukin 2 (IL-2) (+144.1%). Clinical efficacy was previously reported in patients with high IKZF3 expression and high type I interferon (IFN) signature at baseline and confirmed here in those with an especially high IFN signature. Iberdomide decreased the type I IFN gene signature only in patients with high expression at baseline (-81.5%; p<0.001) but decreased other gene signatures in all patients.

CONCLUSION

Iberdomide significantly reduced activity of type I IFN and B cell pathways, and increased IL-2 and Tregs, suggesting a selective rebalancing of immune abnormalities in SLE. Clinical efficacy corresponded to reduction of the type I IFN gene signature.

TRIAL REGISTRATION NUMBER

NCT03161483.

Iberdomide in patients with systemic lupus erythematosus: a randomised, double-blind, placebo-controlled, ascending-dose, phase 2a study

OBJECTIVE

To evaluate safety, pharmacokinetics, pharmacodynamics and efficacy of iberdomide in patients with SLE. Iberdomide is a high-affinity cereblon ligand that targets the hematopoietic transcription factors Ikaros and Aiolos for proteasomal degradation.

METHODS

A 12-week, multicentre, double-blind, placebo-controlled, dose-escalation study in active SLE was followed by a 2-year, open-label active treatment extension phase (ATEP) (NCT02185040). In the dose-escalation phase, adults with active SLE were randomised to oral placebo or iberdomide (0.3 mg every other day, 0.3 mg once daily, 0.6 mg and 0.3 mg alternating once daily, or 0.6 mg once daily). Primary endpoints were safety and tolerability.

RESULTS

The dose-escalation phase enrolled 42 patients, with 33 completing this phase and 17 patients enrolling into the ATEP. In the dose-escalation phase, the most common treatment-emergent adverse events (TEAEs; iberdomide/placebo groups) were nausea (20.6%/12.5%), diarrhoea (17.6%/12.5%) and upper respiratory tract infection (11.8%/12.5%). Most TEAEs were mild or moderate in severity and more common in the highest dose groups in both study phases. In the dose-escalation phase, Physician's Global Assessment and Cutaneous Lupus Erythematosus Disease Area and Severity Index (CLASI) activity scores improved relative to baseline and placebo in all iberdomide groups, with a trend toward continued score improvements in the ATEP. In the dose-escalation phase, iberdomide treatment resulted in dose-dependent reductions in total B cells and plasmacytoid dendritic cells in blood. Improvements in CLASI activity scores correlated with plasmacytoid dendritic cell depletion.

CONCLUSIONS

These proof-of-concept findings suggest a favourable benefit/risk ratio in SLE for iberdomide, a drug with a novel immunomodulatory mechanism of action, supporting further clinical investigation.

Physicochemistry of Cereblon Modulating Drugs Determines Pharmacokinetics and Disposition

Immunomodulatory drugs (IMiDs) thalidomide, lenalidomide, and pomalidomide engage cereblon and mediate a protein interface with neosubstrates such as zinc finger transcription factors promoting their polyubiquitination and degradation. The IMiDs have garnered considerable excitement in drug discovery, leading to exploration of targeted protein degradation strategies. Although the molecular modes-of-action of the IMiDs and related degraders have been the subject of intense research, their pharmacokinetics and disposition have been relatively understudied. Here, we assess the effects of physicochemistry of the IMiDs, the phthalimide EM-12, and the candidate drug CC-220 (iberdomide) on lipophilicity, solubility, metabolism, permeability, intracellular bioavailability, and cell-based potency. The insights yielded in this study will enable the rational property-based design and development of targeted protein degraders in the future.

Key regulators of sensitivity to immunomodulatory drugs in cancer treatment

Immunomodulatory drugs (IMiDs) include thalidomide, lenalidomide, and pomalidomide, which have shown significant efficacy in the treatment of multiple myeloma (MM), myelodysplastic syndrome (MDS) with deletion of chromosome 5q (del(5q)) and other hematological malignancies. IMiDs hijack the CRL4^CRBN ubiquitin ligase to target cellular proteins for ubiquitination and degradation, which is responsible for their clinical activity in MM and MDS with del(5q). However, intrinsic and acquired resistance frequently limit the efficacy of IMiDs. Recently, many efforts have been made to explore key regulators of IMiD sensitivity, resulting in great advances in the understanding of the regulatory networks related to this class of drugs. In this review, we describe the mechanism of IMiDs in cancer treatment and summarize the key regulators of IMiD sensitivity. Furthermore, we introduce genome-wide CRISPR-Cas9 screenings, through which the regulatory networks of IMiD sensitivity could be identified.

Facts and Hopes in Multiple Myeloma Immunotherapy

Among the hallmarks of cancer is the ability of neoplastic cells to evade and suppress immune surveillance to allow their growth and evolution. Nowhere is this as apparent as in multiple myeloma, a cancer of antibody-producing plasma cells, where a complex interplay between neoplastic cells and the immune microenvironment is required for the development and progression of disease. Decades of research has led to the discovery of a number of therapeutic agents, from cytotoxic drugs to genetically engineered cells that mediate their antimyeloma effects at least partially through altering these immune interactions. In this review, we discuss the history of immunotherapy and current practices in multiple myeloma, as well as the advances that promise to one day offer a cure for this deadly disease.