Post hoc analysis of daratumumab plus lenalidomide, bortezomib and dexamethasone in Black patients from final data of the GRIFFIN study.

Due in part to racial disparities and underrepresentation in clinical studies, optimal therapies for Black patients with multiple myeloma remain undefined. This final analysis of GRIFFIN by race showed that the addition of daratumumab (D) to lenalidomide/bortezomib/dexamethasone (RVd) provides clinical benefit among both Black and White transplant-eligible newly diagnosed patients compared with RVd alone. However, Black patients were more likely to discontinue ≥1 drug due to treatment-emergent adverse events. In summary, these findings suggest a benefit of D-RVd front-line therapy among Black and White patients and underscore the importance of equitable treatment access for all patients.

Health-related quality of life in transplant-eligible patients with newly diagnosed multiple myeloma treated with daratumumab, lenalidomide, bortezomib, and dexamethasone: Patient-reported outcomes from GRIFFIN.

In the phase 2 GRIFFIN trial (ClinicalTrials.gov identifier: NCT02874742), daratumumab added to lenalidomide, bortezomib, and dexamethasone (D-RVd) improved depth of response and progression-free survival (PFS) versus lenalidomide, bortezomib, and dexamethasone (RVd) alone in transplant-eligible (TE) patients with newly diagnosed multiple myeloma (NDMM). Here, we present patient-reported outcomes (PROs) collected using the European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire Core 30-item (QLQ-C30), EORTC Quality of Life Questionnaire Multiple Myeloma Module 20-item (QLQ-MY20), and EuroQol 5-Dimension 5-Level (EQ-5D-5L) tools on day 1 of cycles 1, 2, and 3; on day 21 of cycle 4 (end of induction therapy); on day 1 of cycle 5; on day 21 of cycle 6 (end of posttransplant consolidation therapy); and at months 6, 12, 18, and 24 of maintenance therapy. Meaningful improvements from baseline were seen in most of the PRO scales with both treatments after consolidation and were sustained for at least 2 years of maintenance treatment. Large reductions from baseline (~20 points) were especially observed in pain symptoms for both treatment groups, although these were numerically higher for patients receiving D-RVd during the majority of the time points. In addition, improvements in key scales, such as global health status, fatigue symptoms, and physical functioning, were also seen with both D-RVd and RVd. These improvements in health-related quality of life contribute to the totality of evidence supporting the improvement in clinical outcomes such as response rates and PFS with D-RVd in induction, consolidation, and maintenance therapy in TE patients with NDMM.

α-Amino bisphosphonate triazoles serve as GGDPS inhibitors.

Depletion of cellular levels of geranylgeranyl diphosphate by inhibition of the enzyme geranylgeranyl diphosphate synthase (GGDPS) is a potential strategy for disruption of protein transport by limiting the geranylgeranylation of the Rab proteins that regulate intracellular trafficking. As such, there is interest in the development of GGDPS inhibitors for the treatment of malignancies characterized by abnormal protein production, including multiple myeloma. Our previous work has explored the structure-function relationship of a series of isoprenoid triazole bisphosphonate-based GGDPS inhibitors, with modifications having impact on enzymatic, cellular and in vivo activities. We have synthesized a new series of α-amino bisphosphonates to understand the impact of modifying the alpha position with a moiety that is potentially linkable to other agents. Bioassays evaluating the enzymatic and cellular activities of these compounds demonstrate that incorporation of the α-amino group affords compounds with GGDPS inhibitory activity which is modulated by isoprenoid tail chain length and olefin stereochemistry. These studies provide further insight into the complexity of the structure-function relationship and will enable future efforts focused on tumor-specific drug delivery.

Investigation of the activity of a novel tropolone in osteosarcoma.

Osteosarcoma (OS) is a primary malignant bone tumor characterized by frequent metastasis, rapid disease progression, and a high rate of mortality. Treatment options for OS have remained largely unchanged for decades, consisting primarily of cytotoxic chemotherapy and surgery, thus necessitating the urgent need for novel therapies. Tropolones are naturally occurring seven-membered non-benzenoid aromatic compounds that possess antiproliferative effects in a wide array of cancer cell types. MO-OH-Nap is an α-substituted tropolone that has activity as an iron chelator. Here, we demonstrate that MO-OH-Nap activates all three arms of the unfolded protein response (UPR) pathway and induces apoptosis in a panel of human OS cell lines. Co-incubation with ferric chloride or ammonium ferrous sulfate completely prevents the induction of apoptotic and UPR markers in MO-OH-Nap-treated OS cells. MO-OH-Nap upregulates transferrin receptor 1 (TFR1) protein levels, as well as TFR1, divalent metal transporter 1 (DMT1), iron-regulatory proteins (IRP1, IRP2), ferroportin (FPN), and zinc transporter 14 (ZIP14) transcript levels, demonstrating the impact of MO-OH-Nap on iron-homeostasis pathways in OS cells. Furthermore, MO-OH-Nap treatment restricts the migration and invasion of OS cells in vitro. Lastly, metabolomic profiling of MO-OH-Nap-treated OS cells revealed distinct changes in purine and pyrimidine metabolism. Collectively, we demonstrate that MO-OH-Nap-induced cytotoxic effects in OS cells are dependent on the tropolone's ability to alter cellular iron availability and that this agent exploits key metabolic pathways. These studies support further evaluation of MO-OH-Nap as a novel treatment for OS.

Evaluation of geranylgeranyl diphosphate synthase inhibition as a novel strategy for the treatment of osteosarcoma and Ewing sarcoma.

Rab GTPases are critical regulators of protein trafficking in the cell. To ensure proper cellular localization and function, Rab proteins must undergo a posttranslational modification, termed geranylgeranylation. In the isoprenoid biosynthesis pathway, the enzyme geranylgeranyl diphosphate synthase (GGDPS) generates the 20-carbon isoprenoid donor (geranylgeranyl pyrophosphate [GGPP]), which is utilized in the prenylation of Rab proteins. We have pursued the development of GGDPS inhibitors (GGSI) as a novel means to target Rab activity in cancer cells. Osteosarcoma (OS) and Ewing sarcoma (ES) are aggressive childhood bone cancers with stagnant survival statistics and limited treatment options. Here we show that GGSI treatment induces markers of the unfolded protein response (UPR) and triggers apoptotic cell death in a variety of OS and ES cell lines. Confirmation that these effects were secondary to cellular depletion of GGPP and disruption of Rab geranylgeranylation was confirmed via experiments using exogenous GGPP or specific geranylgeranyl transferase inhibitors. Furthermore, GGSI treatment disrupts cellular migration and invasion in vitro. Metabolomic profiles of OS and ES cell lines identify distinct changes in purine metabolism in GGSI-treated cells. Lastly, we demonstrate that GGSI treatment slows tumor growth in a mouse model of ES. Collectively, these studies support further development of GGSIs as a novel treatment for OS and ES.

Daratumumab plus lenalidomide, bortezomib and dexamethasone in newly diagnosed multiple myeloma: Analysis of vascular thrombotic events in the GRIFFIN study.

Patients with multiple myeloma are at increased risk of vascular thromboembolic events (VTEs). This post hoc analysis evaluated VTEs in the randomised phase 2 GRIFFIN study (ClinicalTrials.gov Identifier: NCT02874742) that investigated lenalidomide/bortezomib/dexamethasone (RVd) ± daratumumab (D). Patients with newly diagnosed multiple myeloma who were eligible for autologous stem cell transplantation (ASCT) received D-RVd/RVd induction, high-dose therapy and ASCT, D-RVd/RVd consolidation and up to 2 years of lenalidomide maintenance therapy ± D. VTE prophylaxis was recommended (at least aspirin, ≥162 mg daily) in accordance with International Myeloma Working Group guidelines. In the safety population (D-RVd, n = 99; RVd, n = 102), VTEs occurred in 10.1% of D-RVd patients and 15.7% of RVd patients; grade 2-4 VTEs occurred in 9.1% and 14.7%, respectively. Median time to the first onset of VTE was longer for D-RVd versus RVd patients (305 days vs 119 days). Anti-thrombosis prophylaxis use was similar between arms (D-RVd, 84.8% vs RVd, 83.3%); among patients with VTEs, prophylaxis use at time of first VTE onset was 60.0% for D-RVd and 68.8% for RVd. In summary, the addition of daratumumab to RVd did not increase the incidence of VTEs, but the cumulative VTE incidence was relatively high in this cohort and anti-thrombotic prophylaxis use was suboptimal.

Daratumumab, lenalidomide, bortezomib, and dexamethasone for transplant-eligible newly diagnosed multiple myeloma: the GRIFFIN trial.

Lenalidomide, bortezomib, and dexamethasone (RVd) followed by autologous stem cell transplantation (ASCT) is standard frontline therapy for transplant-eligible patients with newly diagnosed multiple myeloma (NDMM). The addition of daratumumab (D) to RVd (D-RVd) in transplant-eligible NDMM patients was evaluated. Patients (N = 207) were randomized 1:1 to D-RVd or RVd induction (4 cycles), ASCT, D-RVd or RVd consolidation (2 cycles), and lenalidomide or lenalidomide plus D maintenance (26 cycles). The primary end point, stringent complete response (sCR) rate by the end of post-ASCT consolidation, favored D-RVd vs RVd (42.4% vs 32.0%; odds ratio, 1.57; 95% confidence interval, 0.87-2.82; 1-sided P = .068) and met the prespecified 1-sided α of 0.10. With longer follow-up (median, 22.1 months), responses deepened; sCR rates improved for D-RVd vs RVd (62.6% vs 45.4%; P = .0177), as did minimal residual disease (MRD) negativity (10-5 threshold) rates in the intent-to-treat population (51.0% vs 20.4%; P < .0001). Four patients (3.8%) in the D-RVd group and 7 patients (6.8%) in the RVd group progressed; respective 24-month progression-free survival rates were 95.8% and 89.8%. Grade 3/4 hematologic adverse events were more common with D-RVd. More infections occurred with D-RVd, but grade 3/4 infection rates were similar. Median CD34+ cell yield was 8.2 × 106/kg for D-RVd and 9.4 × 106/kg for RVd, although plerixafor use was more common with D-RVd. Median times to neutrophil and platelet engraftment were comparable. Daratumumab with RVd induction and consolidation improved depth of response in patients with transplant-eligible NDMM, with no new safety concerns. This trial was registered at www.clinicaltrials.gov as #NCT02874742.

Current Frontline Treatment of Multiple Myeloma.

Treatment paradigms for management of newly diagnosed (ND) multiple myeloma have been evolving over the past 20 years as a consequence of the development of immunomodulatory drugs, proteasome inhibitors, and monoclonal antibodies. While recent studies have continued to confirm the progression-free survival benefit of consolidation with upfront autologous stem cell transplant in those considered transplant eligible (TE), the line between induction strategies for TE and transplant-ineligible (TI) patients has blurred, based on studies evaluating both populations. Here, we present an overview of the data guiding current treatment approaches in the ND setting and discuss areas of ongoing investigation, including the role of quadruplet combination therapies in TE patients, the optimal strategies for frail TI patients, and management of high-risk disease.

A plain language summary of daratumumab plus lenalidomide/bortezomib/dexamethasone in transplant-eligible Black patients with newly diagnosed multiple myeloma in the GRIFFIN study.

WHAT IS THIS SUMMARY ABOUT?: This is a summary of a publication about Black participants of the GRIFFIN clinical study that was published in Blood Cancer Journal in April 2022. The GRIFFIN clinical study looked at the treatment combination of daratumumab plus a standard therapy for multiple myeloma (called RVd therapy, which stands for lenalidomide, bortezomib, and dexamethasone) in adult patients who had not been treated before for multiple myeloma and so were considered to have newly diagnosed multiply myeloma. Multiple myeloma is a blood cancer of plasma cells. Based on the participants' age, medical history, and indicators of good general health, the participants in the GRIFFIN study were also eligible to receive autologous stem cell transplant as part of their therapy. This summary describes results for the Black participants of the GRIFFIN clinical study who received daratumumab plus RVd therapy (called D-RVd) to see if D-RVd therapy is better than RVd therapy at reducing the amount of multiple myeloma cancer cells in a patient's body. WHY DID THE RESEARCHERS EVALUATE THE RESULTS FOR BLACK PATIENTS IN THE GRIFFIN STUDY?: Due to racial disparities leading to historically low representation of minority groups in clinical studies, optimal treatments are not defined for Black patients with newly diagnosed multiple myeloma. Since previously published results from the overall population in the GRIFFIN study indicated that D-RVd therapy was better than RVd therapy, the researchers wanted to determine if this was also the case among Black participants. WHAT WERE THE RESULTS?: Out of 207 participants in the GRIFFIN study, 15% (32 participants) were Black and 78% (161 participants) were White. In both Black and White participants, D-RVd therapy reduced the amount of myeloma cancer cells more than RVd therapy. Additionally, D-RVd and RVd therapy had similar safety results for Black and White participants. WHAT DO THE RESULTS MEAN?: This analysis of GRIFFIN by race shows that Black people benefit from the daratumumab-containing D-RVd therapy as much as White people. Additionally, D-RVd therapy had similar safety results to RVd therapy for both Black and White people. Clinical Trial Registration: NCT02874742 (ClinicalTrials.gov).

Targeting the Isoprenoid Biosynthetic Pathway in Multiple Myeloma.

Multiple myeloma (MM) is a plasma cell malignancy for which there is currently no cure. While treatment options for MM have expanded over the last two decades, all patients will eventually become resistant to current therapies. Thus, there is an urgent need for novel therapeutic strategies to treat MM. The isoprenoid biosynthetic pathway (IBP) is responsible for the post-translational modification of proteins belonging to the Ras small GTPase superfamily, such as Ras, Rho and Rab family members. Given the important roles these GTPase proteins play in various cellular processes, there is significant interest in the development of inhibitors that disturb their prenylation and consequently their activity in MM cells. Numerous preclinical studies have demonstrated that IBP inhibitors have anti-MM effects, including the induction of apoptosis in MM cells and inhibition of osteoclast activity. Some IBP inhibitors have made their way into the clinic. For instance, nitrogenous bisphosphonates are routinely prescribed for the management MM bone disease. Other IBP inhibitors, including statins and farnesyltransferase inhibitors, have been evaluated in clinical trials for MM, while there is substantial preclinical investigation into geranylgeranyl diphosphate synthase inhibitors. Here we discuss recent advances in the development of IBP inhibitors, assess their mechanism of action and evaluate their potential as anti-MM agents.

In vivo evaluation of combination therapy targeting the isoprenoid biosynthetic pathway.

Geranylgeranyl diphosphate synthase (GGDPS), an enzyme in the isoprenoid biosynthetic pathway (IBP), produces the isoprenoid (geranylgeranyl pyrophosphate, GGPP) used in protein geranylgeranylation reactions. Our prior studies utilizing triazole bisphosphonate-based GGDPS inhibitors (GGSIs) have revealed that these agents represent a novel strategy by which to induce cancer cell death, including multiple myeloma and pancreatic cancer. Statins inhibit the rate-limiting enzyme in the IBP and potentiate the effects of GGSIs in vitro. The in vivo effects of combination therapy with statins and GGSIs have not been determined. Here we evaluated the effects of combining VSW1198, a novel GGSI, with a statin (lovastatin or pravastatin) in CD-1 mice. Twice-weekly dosing with VSW1198 at the previously established maximally tolerated dose in combination with a statin led to hepatotoxicity, while once-weekly VSW1198-based combinations were feasible. No abnormalities in kidney, spleen, brain or skeletal muscle were observed with combination therapy. Combination therapy disrupted protein geranylgeranylation in vivo. Evaluation of hepatic isoprenoid levels revealed decreased GGPP levels in the single drug groups and undetectable GGPP levels in the combination groups. Additional studies with combinations using 50% dose-reductions of either VSW1198 or lovastatin revealed minimal hepatotoxicity with expected on-target effects of diminished GGPP levels and disruption of protein geranylgeranylation. Combination statin/GGSI therapy significantly slowed tumor growth in a myeloma xenograft model. Collectively, these studies are the first to demonstrate that combination IBP inhibitor therapy alters isoprenoid levels and disrupts protein geranylgeranylation in vivo as well as slows tumor growth in a myeloma xenograft model, thus providing the framework for future clinical exploration.

Impact of α-modifications on the activity of triazole bisphosphonates as geranylgeranyl diphosphate synthase inhibitors.

Agents that inhibit the enzyme geranylgeranyl diphosphate synthase (GGDPS) have anti-cancer activity and our prior studies have investigated the structure-function relationship for a family of isoprenoid triazole bisphosphonates as GGDPS inhibitors. To further explore this structure-function relationship, a series of novel α-modified triazole phosphonates was prepared and evaluated for activity as GGDPS inhibitors in enzyme and cell-based assays. These studies revealed flexibility at the α position of the bisphosphonate derivatives with respect to being able to accommodate a variety of substituents without significantly affecting potency compared to the parent unsubstituted inhibitor. However, the monophosphonate derivatives lacked activity. These studies further our understanding of the structure-function relationship of the triazole-based GGDPS inhibitors and lay the foundation for future studies evaluating the impact of α-modifications on in vivo activity.

Long-Term Follow-up of CALGB (Alliance) 100001: Autologous Followed by Nonmyeloablative Allogeneic Transplant for Multiple Myeloma.

CALGB (Alliance) 100001 was a phase II study evaluating autologous stem cell transplant (ASCT) followed by nonmyeloablative allogeneic stem cell transplant (alloSCT) in patients with multiple myeloma who had received no more than 18 months of prior therapy and had experienced no more than 1 prior progression event. Conditioning for ASCT was with high-dose melphalan (200 mg/m2). The alloSCT reduced-intensity conditioning (RIC) regimen consisted of fludarabine (30 mg/m2/d i.v. on days -7 through -3) and cyclophosphamide (1 g/m2/d i.v. on days -4 through -3). The primary objective was to determine the 6-month post-alloSCT treatment-related mortality (TRM) rate. Additional objectives included determining the proportion of patients who could complete this tandem ASCT-alloSCT approach in a cooperative group setting, overall response rates, rates of donor chimerism, rates of graft-versus-host disease (GVHD), disease-free survival, and overall survival (OS). Sixty patients were enrolled, of whom 57 (95%) completed ASCT and 49 (82%) completed tandem ASCT-alloSCT. The TRM rate was 2% (1/49; 90% confidence interval, 0.10% to 9.3%). Moderate to severe (grades 2 to 3) acute GVHD was observed in 13 of 49 alloSCT patients (27%). One patient died due to GVHD within 9 months of alloSCT. Twenty-seven of the 49 patients (55%) who underwent alloSCT reported chronic GVHD as either limited (15/49; 31%) or extensive (12/49; 24%) in the first year post-alloSCT and prior to the start of nonprotocol therapy for progressive disease. With a median follow-up for survival of 11 years, the median OS time is 6.6 years and the median time to disease progression is 3.6 years. Similar to other studies, this study confirmed that tandem ASCT/alloSCT is associated with durable disease control in a subset of patients. This study demonstrated the feasibility of performing tandem ASCT/alloSCT in a cooperative group setting and determined that a fludarabine/cyclophosphamide RIC regimen is associated with a very low TRM rate.

Summary of the Third Annual Blood and Marrow Transplant Clinical Trials Network Myeloma Intergroup Workshop on Minimal Residual Disease and Immune Profiling.

The third annual Blood and Marrow Transplant Clinical Trials Network (BMT CTN) Myeloma Intergroup Workshop on Minimal Residual Disease and Immune Profiling was held on November 29, 2018, at the American Society of Hematology (ASH) annual meeting. This workshop featured the latest research focused on minimal residual disease (MRD) assessment and immune profiling (IP) in myeloma as well as discussion of the statistical and regulatory issues intrinsic to the development of MRD as a surrogate endpoint. In this report, we provide a summary of the workshop and focus on the integration of MRD and IP assessment into trial design and clinical practice.

Summary of the 2019 Blood and Marrow Transplant Clinical Trials Network Myeloma Intergroup Workshop on Minimal Residual Disease and Immune Profiling.

The Blood and Marrow Transplant Clinical Trials Network (BMT CTN) Myeloma Intergroup has organized an annual workshop focused on minimal residual disease (MRD) testing and immune profiling (IP) in multiple myeloma since 2016. In 2019, the workshop took place as an American Society of Hematology (ASH) Friday Scientific Workshop titled "Immune Profiling and Minimal Residual Disease Testing in Multiple Myeloma." This workshop focused on 4 main topics: the molecular and immunologic evolution of plasma cell disorders, development of new laboratory- and imaging-based MRD assessment approaches, chimeric antigen receptor T cell therapy research, and statistical and regulatory issues associated with novel clinical endpoints. In this report, we provide a summary of the workshop and discuss future directions.

Amides as bioisosteres of triazole-based geranylgeranyl diphosphate synthase inhibitors.

Geranylgeranyl diphosphate synthase (GGDPS) inhibitors are of potential therapeutic interest as a consequence of their activity against the bone marrow cancer multiple myeloma. A series of bisphosphonates linked to an isoprenoid tail through an amide linkage has been prepared and tested for the ability to inhibit GGDPS in enzyme and cell-based assays. The amides were designed as analogues to triazole-based GGDPS inhibitors. Several of the new compounds show GGDPS inhibitory activity in both enzyme and cell assays, with potency dependent on chain length and olefin stereochemistry.

Visual Pathway Degeneration in Chemotherapy-Related Neurotoxicity: A Review and Directions for Future Research.

Chemotherapy-related neurotoxicity (CRNT) is an emerging public health concern. Visual pathway degeneration may be a symptom of CRNT. We surveyed the current literature for evidence of visual pathway degeneration in cancer patients receiving chemotherapy. A systematic review was conducted in PubMed. Six published articles met our inclusion criteria. The studies showed reduced retinal thickness, primarily in the retinal nerve fibre layer, and impaired inner retinal function in patients receiving chemotherapy. In summary, the current literature suggests chemotherapy may induce visual pathway degeneration. Future research may benefit from improving study design, exploring mechanisms of chemotherapy-related visual pathway degeneration, and incorporating these findings into biomarker development.

Summary of the Second Annual BMT CTN Myeloma Intergroup Workshop on Minimal Residual Disease and Immune Profiling.

The second annual Blood and Marrow Transplant Clinical Trials Network (BMT CTN) Myeloma Intergroup Workshop on Minimal Residual Disease and Immune Profiling was convened on December 7, 2017, at the American Society of Hematology (ASH) meeting. During this workshop, investigators from around the world presented their latest research involving assessment of minimal residual disease (MRD) and immune profiling (IP) in myeloma. This document summarizes the workshop presentations as well as relevant ASH abstracts and focuses on the regulatory issues involved in the integration of MRD and IP assessment in clinical trial design and practice.

In Vivo Evaluation of Isoprenoid Triazole Bisphosphonate Inhibitors of Geranylgeranyl Diphosphate Synthase: Impact of Olefin Stereochemistry on Toxicity and Biodistribution.

The enzyme geranylgeranyl diphosphate synthase (GGDPS) synthesizes the 20-carbon isoprenoid geranylgeranyl pyrophosphate, which is used in geranylgeranylation reactions. We have demonstrated that GGDPS inhibitors in multiple myeloma (MM) cells disrupt Rab geranylgeranylation, leading to inhibition of monoclonal protein trafficking, induction of the unfolded protein response pathway (UPR), and apoptosis. We have previously reported preclinical studies with the GGDPS inhibitor VSW1198, which is a mixture of homogeranyl/homoneryl triazole bisphosphonates. Additional structure-function efforts have led to development of the α-methylated derivatives RAM2093 (homogeranyl) and RAM2061 (homoneryl). As little is known regarding the impact of olefin stereochemistry on drug properties in vivo, we pursued additional preclinical evaluation of RAM2093 and RAM2061. In MM cell lines, both isomers induce activation of UPR/apoptotic markers in a concentration-dependent manner and with similar potency. Single-dose testing in CD-1 mice identified a maximum tolerated i.v. dose of 0.5 mg/kg for RAM2061 and 0.3 mg/kg for RAM2093. Liver toxicity was the primary barrier to dose escalation for both compounds. Disruption of geranylgeranylation in vivo was confirmed after multidose administration of either compound. Pharmacokinetic studies revealed plasma terminal half-lives of 29.2 ± 6 (RAM2061) and 22.1 ± 4 hours (RAM2093). Relative to RAM2061, RAM2093 levels were significantly higher in liver tissue but not in other tissues. Using MM.1S flank xenografts, we observed a significant reduction in tumor growth in mice treated with RAM2061 relative to controls. Collectively, these studies reveal olefin stereochemistry-dependent effects on GGDPS inhibitor biodistribution and confirm the in vivo efficacy of this novel therapeutic approach. SIGNIFICANCE STATEMENT: These studies reveal olefin stereochemistry-dependent effects on the in vivo properties of two novel triazole bisphosphonate inhibitors of geranylgeranyl diphosphate synthase and demonstrate the therapeutic potential of this class of inhibitors for the treatment of multiple myeloma.

Novel benzimidazole phosphonates as potential inhibitors of protein prenylation.

Benzimidazole carboxyphosphonates and bisphosphonates have been prepared and evaluated for their activity as inhibitors of protein prenylation or isoprenoid biosynthesis. The nature of the phosphonate head group was found to dictate enzyme specificity. The lead carboxyphosphonate inhibits geranylgeranyl transferase II while its corresponding bisphosphonate analogue potently inhibits farnesyl diphosphate synthase. The most active inhibitors effectively disrupted protein prenylation in human multiple myeloma cells.