| ENTREMED • ENMD-1198 |
| PRODUCT DESIGNATION | |
| Other Designation | ENMD-1198 |
| Chemical Name | 2-Methoxyestra-1, 3, 5, (10) 16-tetraene-3-carboxamide |
| Description | ENMD-1198, a novel tubulin binding agent, is the lead among 3 compounds that are new chemical entities based on the antitumor and antiangiogenic agent 2-methoxyestradiol (2-ME2), with a reduced rate of metabolism and improved PK and antitumor activity in animal models. |
| PRODUCT SOURCE | |
| Primary Developer | EntreMed |
| PRODUCT SPECIFICATIONS | |
| Therapeutic Indication | Malignancy |
| Therapeutic Category | Cytotoxic • Regulation |
| Drug Category | Small molecule drug |
| Drug Type | Apoptosis enhancer • Spindle poison |
| Technology | Chemical synthesis |
| Technology Details | EntreMed scientists have modified the chemical structure of 2ME2 to increase its antitumor and antiangiogenic properties and decrease its rate of metabolism. EntreMed has identified three molecules (883, 900 and 5171) that demonstrate improved PK parameters, a reduced rate of metabolism, and enhanced anti-tumor activity in preclinical animal models. EntreMed is evaluating various formulation technologies to optimize absorption, distribution and metabolic properties, as well as anti-tumor activities of these molecules. A lead compound has been selected, ENMD-1198. Preclinical studies in murine models and clinical studies in humans demonstrated that, as reported for estradiol, 2ME2 undergoes significant oxidation at the 17-position to form 2-methoxyestrone (2ME1) as well as extensive conjugation at the 3- and 17-positions. To get a better understanding of the structure-activity relationships and metabolism of 2ME2, several series of new chemical entities (NCE) were designed and synthesized that are modified at position 3 on the A-ring, at position 17 on the D-ring or at both positions simultaneously. Hundreds of NCE were generated with a range of activities. These NCE are screened for antiproliferative activity in vitro using tumor and endothelial cell types. In vitro estrogenicity is tested by the ability of these NCE to support the proliferation of an estrogen-dependent cell line. Several NCE with single or combined substitutions at positions 3 and/or 17 show similar or improved antiproliferative activities and further reduced estrogenicity as compared to 2ME2. Additionally, many of these molecules demonstrate improved PK parameters in rodents. Several of the NCE showing acceptable responses in the in vitro screening assays and having a good PK profile after oral administration are being tested for efficacy in animal tumor models. Their mechanism of action is also being investigated (Lavallee TM, etal, AACR04, Abs. 4085 and AACR-NCI-EORTC03, Abs. A260). Also see Panzem record. |
| Mechanism | Cytotoxicity |
| Mechanism Details | ENMD-1198 exhibits a broad range of antiproliferative activity and significant antitumor activity in preclinical murine models. ENMD-1198 destabilizes microtubules via the colchicine binding site of tubulin, leading to G2/M arrest and apoptosis. A human ovarian carcinoma cell line 1A9-1198R which is about 100-fold more resistant to ENMD-1198 than 1A9 was generated. 1A9-1198R cells displayed similar cross-resistance to 2ME2 and moderate cross-resistance to tubulin-destabilizing agents, combretastatin (11-fold), colchicine (8-fold), vincristine (2.4-fold), and docetaxol (1-fold). Treatment with ENMD-1198 (10 µM) did not induce cell cycle arrest in 1A9-1198R cells, but arrested parental 1A9 cells at the G2/M phase of the cell cycle. Both cell lines were affected equally in response to paclitaxel. ENMD-1198 decreased active pNF-kB and pSTAT3 in 1A9 cells, however treatment of 1A9-1198R cells did not change pNF-kB or pSTAT3 levels. Further analyses revealed point mutations in the beta-I (M40) tubulin isotype, at positions 248 (Alaß-248Thr) and 350 (Lysß-350Asn) in 1A9-1198R cells. ENMD-1198 treatment in 1A9 parental cells decreased a tubulin expression, while 1A9-1198R cells were not affected; beta-I tubulin remained unaffected in both cell lines. Notably, the 1A9-1198R cells expressed less beta-II tubulin than parental 1A9 cells, but beta-II levels did not change following ENMD-1198 treatment, whereas expression decreased after ENMD-1198 treatment in the 1A9 cells. These data suggest that the antitumor activity and inhibition of HIF-1alpha, STAT3 and NFkappaB are a result of the tubulin-binding properties of ENMD-1198, and the mutations in the beta- tubulin isotypes are important for in vitro-derived ENMD-1198 resistance. Further, ENMD-1198 resistant 1A9 cells may provide a useful tool for evaluating a pharmacogenomic profile that can be correlated with clinical benefit. (Tobin GM, etal, AACR08. Abs. 3275). Scientists from the University of Colorado Health Sciences Center (Denver, CO) and EntreMed evaluated the in vitro and in vivo mechanisms of action responsible for the antitumor activity of ENMD-1198. MDA-MB-231 breast cancer cells demonstrated decreased levels of hypoxia-inducible factor-1alpha (HIF-1alpha), nuclear factor kappaB (NFkappaB), and Stat3 transcription factors, microtubule disruption, and loss of microtubule stability, suggesting that ENMD-1198 interferes with activation of latent forms of transcription factors or impairs translocation of active forms of transcription factors to the nucleus. MDA-MB-231 orthotopic tumors demonstrated decreased HIF-1alpha, NFkappaB and Stat3 staining following daily oral dosing of ENMD-1198. In this model, treatment resulted in a 94% reduction in tumor burden with decreased acetylated tubulin, carbonic anhydrase IX, proliferation (Ki-67) and angiogenesis (CD-31). Circulating human vascular endothelial growth factor and human interleukin-6 (modulated by HIF-1alpha and Stat3, and NF-kappaB, respectively) decreased. The significant antitumor activity and associated inhibition of HIF-1alpha, NFkappaB and Stat3 demonstrated in preclinical models support the evaluation of ENMD-1198 in IND-directed studies, while ongoing studies will aid in the design of clinical trials of ENMD-1198 (Burke PA, etal, AACR06, Abs. 491). To support IND development, acute dose range finding and chronic multiple dose studies were performed with ENMD-1198 in rats and dogs for up to 28 days. Effects of ENMD-1198 in both species after 28 days of administration were similar in character to those in shorter term studies. Organs affected by ENMD-1198 were those with cell populations of high mitotic potential, including bone marrow, lymph nodes, spleen, thymus, gastrointestinal tract, and testes. Liver findings were also regularly reported, including increases in organ weight, elevations in liver function tests (LFT), and histopathology. Most findings in the 28-day studies were partially or fully recovered after a 14-day drug free period. At a given dose, higher exposures were achieved in dogs compared to rats, and in female compared to male rats. Cmax and AUC values in rats after 28 days of administration associated with the no observed effect level (NOEL) are NOEL at 5 mg/kg/day (30 mg/m²), Cmax at 280 ng/mL, and AUC at 1068 ng hour/mL. Cmax and AUC values in dogs are NOEL at 20 mg/kg/day (400 mg/m²); Cmax at 3689 ng/mL, and AUC at 33320 ng hour/mL. On day 28, Cmax and AUC values of ENMD-1198 were comparable to day 1 values in both species. ENMD-1198 is tolerated at higher levels in mice and dogs than in rats. While ENMD-1198 shows different tolerability in mice and rats, a therapeutic window was demonstrated in both species using xenograft tumor models. Toxicities with ENMD-1198 are consistent with its microtubule destabilizing activities (LaVallee T, etal, AACR-NCI-EORTC05, Abs. B240). Daily oral dosing of ENMD-1198 for 28 days yielded a 10-fold difference between the MTD of rats and dogs. MTD in female rats is 60 mg/m²/day, resulting in a Cmax of 927 ng/mL and AUC of 3724 ng*hour/mL. MTD in female dogs is 600 mg/m²/day, resulting in a Cmax of 4396 ng/mL and AUC of 29235 ng*hour/mL. Consistent with its mechanism of action, ENMD-1198 in both species affected organs with cell populations of high mitotic potential (bone marrow, lymph nodes, spleen, thymus, GI tract, and testes). Data from rats (the most sensitive species) were used to determine the starting dose in a first-in-man phase I clinical trial of ENMD-1198 in patients with advanced cancer (LaVallee T, etal, AACR-NCI-EORTC07, Abs. B99). In October 2005, positive preclinical results for ENMD-1198 were presented by EntreMed scientists during an oral presentation at the International Tumor Metabolism Summit held in Genova, Italy. Oral administration of ENMD-1198 showed pronounced in vivo antitumor activity in preclinical models of human cancer. Oral daily treatment with ENMD-1198 in an orthotopic MDA MB 231 breast cancer model led to disruption of microtubules within tumor cells, and a substantial decrease in cells staining positively for HIF-1alpha. HIF-1alpha is overexpressed in more than 70% of human tumors, and its overexpression correlates with tumor aggressiveness, metastases, and poor prognosis. Protein levels for two additional transcription factors, NFkB and Stat3, known to modulate HIF-1alpha protein levels in vitro, were also reduced following daily oral ENMD-1198 treatment, as determined by decreased nuclear staining for active transcription factor proteins. In addition to their relationship to HIF-1alpha protein, all three transcription factors are known to regulate multiple genes and their proteins that contribute to tumor growth and progression. Serum proteins regulated by HIF-1alpha, NFkB, and Stat3 were also reduced substantially following oral administration of ENMD-1198 in a preclinical orthotopic breast cancer model. Results from several studies demonstrate substantially (40%-100%) decreased plasma or serum levels of human VEGF compared to control animals following therapy with ENMD-1198. Serum levels of human IL-6, which is modulated by NFkB, were also decreased significantly (62%-96%) with ENMD-1198. Overexpression of IL-6 is associated with higher morbidity in breast cancer, bone metastases, increased aromatase synthesis, and increased cancer drug resistance. Tumor levels of a third tumor protein regulated by HIF-1alpha, carbonic anhydrase IX (CA IX), as determined by decreased cytoplasmic staining on tumor cells were also decreased, consistent with HIF-1alpha inhibition. In order to improve bioavailability and increase activity, a series of 2ME2 analogs modified at position 3 on the A-ring and position 17 on the D-ring were designed and synthesized. These analogs retain antitumor and antiangiogenic activities in vitro, and demonstrate improved oral PK parameters in preclinical models. Up to 3 lead analogs (883, 900, and 5171) have been selected for further preclinical studies. Similar to 2ME2, the analogs show a broad range of antiproliferative activity. IC50 values for 14 different tumor cell lines range from 0.07-0.37 µM for 883, 0.08-0.74 µM for 900, and 0.73-5.64 µM for 5171, as compared to 0.23-2.20 for 2ME2. All 3 compounds demonstrate good oral bioavailability in mice (883 F=59%, 900 F=43%, and 5171 F=50%), and decreased metabolism by rat and human hepatocyes in vitro. The lead analogs are microtubule-destabilizing agents, as demonstrated by indirect immunofluorescence and immunoblotting, and cause a reduction of HIF-1alpha protein in vitro. Interestingly, in vivo oral delivery of 883 and 5171, but not 900, resulted in significantly improved MST in a Lewis lung carcinoma metastatic model compared to vehicle-treated mice. Significantly reduced tumor volumes were observed following treatment with all 3 analogs in an MDA MB 231 orthotopic model (883: T/C 0.23; 900: T/C 0.51; 5171: T/C 0.37). Given the robust antitumor activity, enhanced microtubule disruption, and HIF-1alpha inhibition, analog 883 is undergoing further evaluation for use as an anticancer agent (Burke P, etal, AACR05, Abs. 5847). 2-ME2, an endogenous metabolite of estradiol-17beta, inhibits tumor angiogenesis while also exerting potent cytotoxic effects on various cancer cells. Antitumor activities of the 3 lead compounds, include the ability to induce apoptosis, target microtubules, and inhibit HIF-1 aplha. HIF-1 is overexpressed in more than 70% of human malignancies and metastases, including breast, prostate, brain, lung, and head and neck cancer. In addition, preclinical studies indicate that ENMD-1198 inhibits NFkappaB and Stat3, known to promote tumorigenesis, and exerts antiangiogenic effects. 2-ME2 activates the p38 MAPK and JNK pathways and induces apoptosis in cells. Expression of Smad7, an adaptor molecule required to activate p38 MAPK in the transforming growth factor beta signaling pathway, is also required for 2-ME-induced p38 activation and apoptosis in human prostate cancer cells (PC-3U). PC-3U/AS-S7 cells stably transfected with an antisense Smad7 construct, or PC-3U cells transiently transfected with short interfering RNA for Smad7, were protected against 2-ME-induced apoptosis. Smad7 was shown by both antisense and short interfering RNA techniques to affect levels of beta-catenin, which has been implicated previously in the regulation of apoptosis. Moreover, Smad7 was found to be important for the basal expression of Bim, a pro-apoptotic Bcl-2 family member, and for 2-ME-induced expression of Bim. These results suggest that expression of Smad7 is crucial for 2-ME-induced apoptosis in human prostate cancer cells (Davoodpour P, etal, J Biol Chem, 15 Apr 2005;280(15):14773-9). |
| Target | Microtubules • Hypoxia inducible factor 1 alpha (HIF-1alpha) |
| Administration Route | PO |
| Delivery Details | |
| Toxicities | Preclinical toxicology studies demonstrate that ENMD-1198 affects cell populations with a high proliferative rate, including bone marrow, gastrointestinal tract and lymphoid organs. These effects are common with approved cancer agents and can be monitored in the clinic. |
| Diagnostic Test/Biomarker Detail | |
| Cancer Indication | solid tumor • hematologic malignancy • breast cancer • prostate cancer • lung cancer • brain cancer • lung cancer • head and neck cancer • leukemia |
| Preclinical History | A preclinical study of ENMD-1198 in an nsclc model demonstrated a 3-fold increase in survival compared to cisplatin. Approximately 80% of the ENMD-1198 treated models remained on study until tumor dissemination evaluation. In prior preclinical studies, ENMD-1198 has been shown to be an orally active, antimitotic agent that leads to arrest of cell division and apoptosis in tumor cells. ENMD-1198 also exerts antiangiogenic activity that further contributes to its overall antitumor effects. The mechanism-of-action for ENMD-1198 indicates that prostate cancer may be a key indication. EntreMed, in collaboration with the Children's Cancer Institute Australia (Randwick, Australia), investigated the antiproliferative activity of ENMD-1198 against drug-resistant leukemia, using CCRF-CEM leukemia cells selected for resistance to vincristine, vinblastine, desoxyepothilone B or 2ME2. Despite these cells harboring a range of resistance mechanisms associated with drug transport or microtubule alterations, no significant cross-resistance was observed with ENMD-1198. The exceptions were low level cross resistance in the vinblastine-selected cells (1.6-fold; p<0.05) and 2ME2-selected cells that exhibit 47-fold resistance to the parent compound but only 1.7-fold resistance to ENMD-1198 (P<0.001). A clinically relevant model of primary human acute lymphocytic leukemia (ALL) cells were xenografted into immunodeficient (NOD/SCID) mice to assess the preclinical efficacy of ENMD-1198. Treatment with ENMD-1198 significantly prolonged mouse survival rates compared to vehicle control in all three human ALL xenografts (ALL3, ALL7 and ALL19) that exhibit intrinsic differences in response to vincristine (p<0.005). Growth delay factors induced by ENMD-1198 for ALL3, ALL7 and ALL19, ranged between 17 and 21 days. Therefore, ENMD-1198 may prove to be a valuable agent to treat drug-resistant leukemia (Liaw TTY, etal, AACR07, Abs. 1439). MADB-106, a highly tumorigenic breast line syngeneic to Fischer 344 rats, was used as a rat tumor model to evaluate and define the therapeutic window of ENMD-1198. In rats bearing subcutaneous MADB-106 tumors, there was a dose-dependant reduction in tumor growth. In an intermittent dosing schedule in the MADB-106 tumor model resulted in statistically significant inhibition of tumor growth when compared to vehicle-treated controls. Antitumor activity was observed in the absence of weight loss or any other overt toxicity. Over the course of the study, vehicle control animals displayed a tumor-induced increase in segmented neutrophil counts (460%) which were reduced with ENMD-1198 significantly (40% to 92%), depending on the treatment dose. This study demonstrates that ENMD-1198 has significant antitumor activity as a monotherapy at a tolerable dose in a rat model of breast cancer (Strawn SJ, AACR07, Abs. 3285). |
| CLINICAL STATUS BY INDICATION | |
| Indication | solid tumors, advanced, refractory |
| Latest Status | Phase I (begin 5/06, ongoing 11/08) USA; phase I (begin 05/06, ongoing 11/07) USA |
| Clinical History |
According to updated information, in the first-in-human, phase I clinical trial of ENMD-1198 in patients with advanced cancer, metabolite profiles from ENMD-1198-dosed rats and dogs were compared to plasma samples from patients dosed with ENMD-1198 (30 mg/m²). Consistent with preclinical data from rats and dogs, oral ENMD-1198 administered OD in humans demonstrated dose proportionality across the dose range of 5-30 mg/m². At 5, 10, 20, and 30 mg/m², mean peak plasma exposures are 68.8, 141.2, 418.7, and 677.8 ng/mL, respectively. Plasma concentration-time curves have resulted in AUC values of 390.0, 1373.8, 2515.4 and 5880.8 ng*hour/mL, respectively, and a half life of approximately 13 hours. Similar to dogs, ENMD-1198 was the major component in human plasma at all time points. No dominant metabolites (>20% of total area of the identified peak) were found in human, rat or dog plasma. M7a/b and M10, hydroxylated ENMD-1198, are the most abundant plasma metabolites in all 3species. There is a significant species difference in sensitivity, but no differences in dominant metabolites (LaVallee T, etal, AACR-NCI-EORTC07, Abs. B99). In November 2008, the phase I clinical trial with ENMD-1198 was nearing completion as DLT was reached. In May 2006, EntreMed commenced a single center, dose-escalation phase I clinical trial to evaluate the safety, tolerability, PK, and clinical benefit of ENMD-1198, in patients with advanced cancer refractory to existing therapies or for which no approved therapy is available. The trial is being conducted at the University of Colorado (Denver, CO) and the Health Sciences Center (Aurora, CO), under PI D. Ross Camidge, MD, PhD. In November 2005, the FDA accepted an IND application for ENMD-1198, to enter into phase I clinical trial in 2006. |
| Product Comment | In March 2008, EntreMed reprioritized its development pipeline to focus investment on ENMD-1198. |
| Patent/Legal Issues | In February 2006, the USPTO issued EntreMed patent #6,995,278 covering analogs of its lead compound, 2-methoxyestradiol (2ME2 or Panzem). The patent grants composition-of-matter intellectual property protection through 2020 for 2ME2 analogs in oncology and nononcology indications, including inflammatory and immune disorders, rheumatoid arthritis, and other mitotic diseases. The patent also claims methods for modifying 2ME2 to obtain the analogs and for treating diseases with the analog. The analogs are modifications to the 2ME2 structure that still inhibit cell proliferation. ENMD-1198 is the lead compound resulting from the 2ME2 analog program. ENMD-1198 and related compounds were discovered by EntreMed and all intellectual property belongs exclusively to the company. |
| Market Opportunities | |
| References | |
| Current as of | March 12, 2009 |