Rigosertib versus best supportive care for patients with high-risk myelodysplastic syndromes after failure of hypomethylating drugs (ONTIME): a randomised, controlled, phase 3 trial.

BACKGROUND: Hypomethylating drugs are the standard treatment for patients with high-risk myelodysplastic syndromes. Survival is poor after failure of these drugs; there is no approved second-line therapy. We compared the overall survival of patients receiving rigosertib and best supportive care with that of patients receiving best supportive care only in patients with myelodysplastic syndromes with excess blasts after failure of azacitidine or decitabine treatment. METHODS: We did this randomised controlled trial at 74 hospitals and university medical centres in the USA and Europe. We enrolled patients with diagnosis of refractory anaemia with excess blasts (RAEB)-1, RAEB-2, RAEB-t, or chronic myelomonocytic leukaemia based on local site assessment, and treatment failure with a hypomethylating drug in the past 2 years. Patients were randomly assigned (2:1) to receive rigosertib 1800 mg per 24 h via 72-h continuous intravenous infusion administered every other week or best supportive care with or without low-dose cytarabine. Randomisation was stratified by pretreatment bone marrow blast percentage. Neither patients nor investigators were masked to treatment assignment. The primary outcome was overall survival in the intention-to-treat population. This study is registered with ClinicalTrials.gov, NCT01241500. FINDINGS: From Dec 13, 2010, to Aug 15, 2013, we enrolled 299 patients: 199 assigned to rigosertib, 100 assigned to best supportive care. Median follow-up was 19·5 months (IQR 11·9-27·3). As of Feb 1, 2014, median overall survival was 8·2 months (95% CI 6·1-10·1) in the rigosertib group and 5·9 months (4·1-9·3) in the best supportive care group (hazard ratio 0·87, 95% CI 0·67-1·14; p=0·33). The most common grade 3 or higher adverse events were anaemia (34 [18%] of 184 patients in the rigosertib group vs seven [8%] of 91 patients in the best supportive care group), thrombocytopenia (35 [19%] vs six [7%]), neutropenia (31 [17%] vs seven [8%]), febrile neutropenia (22 [12%] vs ten [11%]), and pneumonia (22 [12%] vs ten [11%]). 41 (22%) of 184 patients in the rigosertib group and 30 (33%) of 91 patients in the best supportive care group died due to adverse events and three deaths were attributed to rigosertib treatment. INTERPRETATION: Rigosertib did not significantly improve overall survival compared with best supportive care. A randomised phase 3 trial of rigosertib (NCT 02562443) is underway in specific subgroups of patients deemed to be at high risk, including patients with very high risk per the Revised International Prognostic Scoring System criteria. FUNDING: Onconova Therapeutics, Leukemia & Lymphoma Society.

Sacituzumab Govitecan, a Novel Antibody--Drug Conjugate, in Patients With Metastatic Platinum-Resistant Urothelial Carcinoma.

Patients with metastatic, platinum-resistant urothelial carcinoma (PRUC) have no Food and Drug Administration-approved therapies. The response rates to second-line chemotherapy have generally been < 20%, with a median overall survival of < 1 year. We report our experience with 6 heavily pretreated patients with advanced PRUC (ClinicalTrials.gov identifier NCT01631552) with the novel antibody-drug conjugate, sacituzumab govitecan (IMMU-132). This antibody-drug conjugate comprises the active metabolite of irinotecan, SN-38, conjugated to an anti-Trop-2 antibody. Trop-2 is widely expressed in ≤ 83% of urothelial carcinomas. Of the 6 patients, 3 had a clinically significant response (progression-free survival, 6.7 to 8.2 months; overall survival, 7.5+ to 11.4+ months). Sacituzumab govitecan was well tolerated. Because of these results, a phase II trial has been initiated. The present report highlights the promise of antibody-drug conjugates, such as sacituzumab govitecan, as a novel therapeutic strategy for the treatment of PRUC.

Clinical activity and safety of the dual pathway inhibitor rigosertib for higher risk myelodysplastic syndromes following DNA methyltransferase inhibitor therapy.

Rigosertib (ON 01910.Na) is an inhibitor of the phosphoinositide 3-kinase and polo-like kinase pathways that induces mitotic arrest and apoptosis in neoplastic cells, while sparing normal cells. Our purpose is to summarize the clinical activity and safety of intravenous (IV) rigosertib delivered by an external ambulatory infusion pump in patients with refractory anemia with excess blasts-1, -2, or, -t myelodysplastic syndromes (MDS) following prior treatment with DNA methyltransferase (DNMT) inhibitors. A total of 39 patients with MDS who fulfilled these criteria were enrolled in four phase 1-2 clinical trials of IV rigosertib. Thirty five (88%) had higher risk disease according to the Revised International Prognostic Scoring System. Median overall survival for this group of 39 patients was 35 weeks. Of 30 evaluable patients with follow-up bone marrow biopsies, 12 (40%) achieved complete (n = 5) or partial (n = 7) bone marrow blast responses. In addition, 15 patients achieved stabilization of bone marrow blasts. One patient with a complete bone marrow response also achieved a complete cytogenetic response. A second patient with stable bone marrow blasts achieved a partial cytogenetic response. Two of the responding patients and three patients with stable disease had hematological improvements. Rigosertib-induced bone marrow blast decreases and stability appeared to be predictive of prolonged survival. IV rigosertib had a favorable safety profile without significant myelosuppression. Most common drug-related toxicities included fatigue, diarrhea, nausea, dysuria, and hematuria. In summary, IV rigosertib is well tolerated and has clinical activity in patients with higher risk MDS following DNMT inhibitor treatment. A multinational pivotal phase 3 randomized clinical trial of rigosertib versus best supportive care for patients with MDS with excess blasts following prior treatment with DNMT inhibitors (ONTIME: ON 01910.Na Trial In Myelodysplastic SyndromE) has recently completed enrollment.

Phase I study of oral rigosertib (ON 01910.Na), a dual inhibitor of the PI3K and Plk1 pathways, in adult patients with advanced solid malignancies.

PURPOSE: To determine the pharmacokinetics (PK), maximum tolerated dose (MTD), safety, and antitumor activity of an oral formulation of rigosertib, a dual phosphoinositide 3-kinase (PI3K) and polo-like kinase 1 (Plk1) pathway inhibitor, in patients with advanced solid malignancies. EXPERIMENTAL DESIGN: Patients with advanced solid malignancies received rigosertib twice daily continuously in 21-day cycles. Doses were escalated until intolerable grade ≥2 toxicities, at which point the previous dose level was expanded to define the MTD. All patients were assessed for safety, PK, and response. Urinary PK were performed at the MTD. Archival tumors were assessed for potential molecular biomarkers with multiplex mutation testing. A subset of squamous cell carcinomas (SCC) underwent exome sequencing. RESULTS: Forty-eight patients received a median of 2 cycles of therapy at 5 dose levels. Rigosertib exposure increased with escalating doses. Dose-limiting toxicities were hematuria and dysuria. The most common grade ≥2 drug-related toxicities involved urothelial irritation. The MTD is 560 mg twice daily. Activity was seen in head and neck SCCs (1 complete response, 1 partial response) and stable disease for ≥12 weeks was observed in 8 additional patients. Tumors experiencing ≥partial response had PI3K pathway activation, inactivated p53, and unique variants in ROBO3 and FAT1, two genes interacting with the Wnt/ß-catenin pathway. CONCLUSIONS: The recommended phase II dose of oral rigosertib is 560 mg twice daily given continuously. Urinary toxicity is the dose-limiting and most common toxicity. Alterations in PI3K, p53, and Wnt/ß-catenin pathway signaling should be investigated as potential biomarkers of response in future trials.

The dual pathway inhibitor rigosertib is effective in direct patient tumor xenografts of head and neck squamous cell carcinomas.

The dual pathway inhibitor rigosertib inhibits phosphoinositide 3-kinase (PI3K) pathway activation as well as polo-like kinase 1 (PLK1) activity across a broad spectrum of cancer cell lines. The importance of PIK3CA alterations in squamous cell carcinoma of the head and neck (HNSCC) has raised interest in exploring agents targeting PI3K, the product of PIK3CA. The genetic and molecular basis of rigosertib treatment response was investigated in a panel of 16 HNSCC cell lines, and direct patient tumor xenografts from eight patients with HNSCC [four HPV-serotype16 (HPV16)-positive]. HNSCC cell lines and xenografts were characterized by pathway enrichment gene expression analysis, exon sequencing, gene copy number, Western blotting, and immunohistochemistry (IHC). Rigosertib had potent antiproliferative effects on 11 of 16 HPV(-) HNSCC cell lines. Treatment sensitivity was confirmed in two cell lines using an orthotopic in vivo xenograft model. Growth reduction after rigosertib treatment was observed in three of eight HNSCC direct patient tumor lines. The responsive tumor lines carried a combination of a PI3KCA-activating event (amplification or mutation) and a p53-inactivating event (either HPV16- or mutation-mediated TP53 inactivation). In this study, we evaluated the in vitro and in vivo efficacy of rigosertib in both HPV(+) and HPV(-) HNSCCs, focusing on inhibition of the PI3K pathway. Although consistent inhibition of the PI3K pathway was not evident in HNSCC, we identified a combination of PI3K/TP53 events necessary, but not sufficient, for rigosertib sensitivity.

Phase 1 study of intravenous rigosertib (ON 01910.Na), a novel benzyl styryl sulfone structure producing G2/M arrest and apoptosis, in adult patients with advanced cancer.

Rigosertib (ON 01910.Na), a synthetic novel benzyl styryl sulfone, was administered to 28 patients with advanced cancer in a Phase I trial in order to characterize its pharmacokinetic profile, determine the dose-limiting toxicities (DLT), define the recommended phase II dose (RPTD) and to document any antitumor activity. Patients with advanced malignant neoplasms refractory to standard therapy were given escalating doses of rigosertib (50, 100, 150, 250, 325, 400, 650, 850, 1,050, 1,375, 1,700 mg/m(2)/24h) as a 3-day continuous infusion (CI) every 2 weeks. An accelerated Fibonacci titration schedule with specified decreases for toxicities was used for escalation until grade ≥2 toxicity occurred. Intrapatient dose escalation was allowed if toxicity was grade ≤2 and the disease remained stable. Plasma pharmacokinetics (PK) and urinary PK assessments were studied in the 1st and 4th cycles. Twenty-nine patients (12 men and 17 women; age 36-87 y with a median of 63 y) were registered, but one died before study drug was given. Twenty-eight patients received a median of 3 cycles of therapy. Most common grade ≥2 toxicities attributable to rigosertib included fatigue, anorexia, vomiting and constipation. DLTs included muscular weakness, hyponatremia, neutropenia, delirium and confusional state. Risk factors for severe toxicities include pre-existing neurological dysfunction or advanced gynecologic cancer after pelvic surgery. Rigosertib pharmacokinetics showed rapid plasma distribution phases and urinary excretion. Elevations in plasma Cmax and AUC due to decreases in plasma clearance were associated with acute grade ≥3 toxicities. Of 22 evaluable patients, 9 (41%) achieved a best overall response of stable disease; all other patients (n=13; 59%) progressed. The median progression-free survival time was 50 days (95% confidence interval [CI]: 37-80 days). Nine (41%) patients survived for over 1 y. In summary, prolonged IV infusions of rigosertib were generally well tolerated. Nine (41%) patients achieved stable disease and 9 (41%) patients survived for over 1 year. The RPTD appears to be 850 mg/m(2)/24hr CI x 3 days. (ClinicalTrials.gov identifier: NCT01538537).

Phase I clinical trial of oral rigosertib in patients with myelodysplastic syndromes.

The multi-kinase inhibitor rigosertib (ON 01910.Na) induces mitotic arrest and apoptosis in myeloblasts, while sparing normal cells. The purpose of this study was to determine the pharmacokinetic profile, maximum-tolerated dose (MTD), safety, and clinical activity of an oral formulation of rigosertib in patients with myelodysplastic syndromes (MDS). For pharmacokinetic studies, patients received rigosertib in single escalating weekly doses. To determine the MTD, patient cohorts received escalating doses of rigosertib twice daily for 14 d of a 21-d cycle. Overall, 37 patients were treated. Rigosertib exposure increased with escalating oral doses. Mean absolute oral bioavailability ranged from 13·9% (fed) to 34·8% (fasting) in 12 patients treated at the 560 mg b.i.d. dose level. Dose-limiting toxicity (grade 3 dysuria and shortness of breath) occurred at the 700 mg b.i.d. dose. Five patients experienced grade 3 non-haematological toxicity, including symptoms of urothelial inflammation, hypotension and syncope, fatigue and abdominal pain. Encouraging signs of clinical activity included two bone marrow complete remissions in refractory anaemia with excess blasts type 1 patients previously treated with azacitidine. In addition, four patients each achieved transfusion independence and haematological improvements. In conclusion, oral rigosertib is bioavailable and well tolerated, and has clinical activity in patients with MDS.

Directed therapy for patients with myelodysplastic syndromes (MDS) by suppression of cyclin D1 with ON 01910.Na.

BACKGROUND: We previously demonstrated upregulation of c-myc, survivin, and cyclin D1 in CD34+ bone marrow mononuclear cells (BMMNCs) of patients with trisomy 8 and monosomy 7 myelodysplastic syndromes (MDS). "Knockdown" of cyclin D1 by RNA interference decreased trisomy 8 cell growth, suggesting that this might be a therapeutic target in MDS. EXPERIMENTAL DESIGN: We performed preclinical studies using BMMNCs from patients with MDS and AML to examine the effects of the styryl sulfone ON 01910.Na on cyclin D1 accumulation, aneuploidy, and CD34+ blast percentage. We next treated twelve patients with higher risk MDS and two trisomy 8 AML patients with ON 01910.Na on a phase I clinical protocol (NCT00533416). RESULTS: ON 01910.Na inhibited cyclin D1 expression, and was selectively toxic to trisomy 8 cells in vitro. Flow cytometry studies demonstrated increased mature CD15+ myeloid cells and decreased CD34+ blasts. Three patients treated with ON 01910.Na on a clinical had decreased bone marrow blasts by ≥ 50%, and three patients had hematologic improvements, one of which was sustained for 33 months. Patients with hematologic responses to ON 01910.Na had decreased cyclin D1 expression in their CD34+ cells. CONCLUSIONS: The preclinical results and responses of patients on a clinical trial warrant further investigation of ON 01910.Na as a potential novel targeted therapy for higher risk MDS patients.

Phase I study of Rigosertib, an inhibitor of the phosphatidylinositol 3-kinase and Polo-like kinase 1 pathways, combined with gemcitabine in patients with solid tumors and pancreatic cancer.

PURPOSE: Rigosertib, a dual non-ATP inhibitor of polo-like kinase 1 (Plk1) and phosphoinositide 3-kinase pathways (PI3K), and gemcitabine have synergistic antitumor activity when combined in preclinical studies. This phase I study aimed to determine the recommended phase II dose (RPTD) of the combination of rigosertib and gemcitabine in patients with cancer. EXPERIMENTAL DESIGN: Patients with solid tumors who failed standard therapy or were candidates for gemcitabine-based therapy were eligible. Gemcitabine was administered on days 1, 8, and 15 on a 28-day cycle and rigosertib on days 1, 4, 8, 11, 15, and 18. Pharmacokinetic studies were conducted during an expansion cohort of patients with advanced pancreatic ductal adenocarcinoma (PDA). RESULTS: Forty patients were treated, 19 in the dose-escalation phase and 21 in the expansion cohort. Dose levels evaluated were (gemcitabine/rigosertib mg/m(2)): 750/600 (n = 4), 750/1,200 (n = 3), 1,000/600 (n = 3), 1,000/1,200 (n = 3), and 1,000/1,800 (n = 6 + 21). One dose-limiting toxicity (death) occurred at the highest dose level (1,000/1,800) tested. Non-dose-limiting ≥grade II/III toxicities included neutropenia, lymphopenia, thrombocytopenia, fatigue, and nausea. Grade III/IV neutropenia, thrombocytopenia, and fatigue were seen in two, one, and two patients in the expansion cohort. Partial responses were observed in PDA, thymic cancer, and Hodgkin lymphoma, including gemcitabine-pretreated PDA. The pharmacokinetic profile of rigosertib was not affected by gemcitabine. CONCLUSION: The RPTD established in this study is rigosertib 1,800 mg/m(2) and gemcitabine 1,000 mg/m(2). This regimen is well tolerated with a toxicity profile of the combination similar to the profile of gemcitabine alone. Antitumor efficacy was observed in patients who previously progressed on gemcitabine-based therapy.

Treatment of higher risk myelodysplastic syndrome patients unresponsive to hypomethylating agents with ON 01910.Na.

In a Phase I/II clinical trial, 13 higher risk red blood cell-dependent myelodysplastic syndrome (MDS) patients unresponsive to hypomethylating therapy were treated with the multikinase inhibitor ON 01910.Na. Responses occurred in all morphologic, prognostic risk and cytogenetic subgroups, including four patients with marrow complete responses among eight with stable disease, associated with good drug tolerance. In a subset of patients, a novel nanoscale immunoassay showed substantially decreased AKT2 phosphorylation in CD34+ marrow cells from patients responding to therapy but not those who progressed on therapy. These data demonstrate encouraging efficacy and drug tolerance with ON 01910.Na treatment of higher risk MDS patients.

Initiation of epoetin-alpha therapy at a starting dose of 120,000 units once every 3 weeks in patients with cancer receiving chemotherapy: an open-label, multicenter study with randomized and nonrandomized treatment arms.

BACKGROUND: Epoetin-alpha initiated once weekly, followed by once-every-3-weeks maintenance, was effective and well tolerated for chemotherapy-induced anemia. This study evaluated a starting dose of epoetin-alpha 120,000 U once every 3 weeks for chemotherapy-induced anemia using early and late initiation regimens. METHODS: Patients with baseline hemoglobin 11.0-12.0 g/dL were randomly assigned to early intervention with immediate epoetin-alpha (n = 68) or to standard intervention with epoetin-alpha when hemoglobin decreased to <11 g/dL (n = 68). A third group of patients with baseline hemoglobin <11 g/dL (n = 50) were enrolled but not randomized; epoetin-alpha was initiated immediately. The primary endpoint was mean proportion of hemoglobin values within the target range (11.0-13.0 g/dL) among randomized patients. RESULTS: The mean proportion of hemoglobin values in range through week 16 was 60% in each randomized group. Mean hemoglobin by week showed similar increases over the study. Blood transfusions were administered in 9%, 8%, and 24% of patients in the early, standard, and nonrandomized groups. Mean epoetin-alpha doses were similar between treatment groups. Dose reductions and withholds were more common in the early intervention group. Adverse events (eg, diarrhea, fatigue, nausea) were consistent with the safety profile for epoetin-alpha . Clinically relevant thrombotic vascular events (regardless of relationship to study treatment) were reported for 9%, 12%, and 12% of patients in the early, standard, and nonrandomized groups. CONCLUSIONS: Early and standard intervention with epoetin-alpha, administered once every 3 weeks, increased and maintained hemoglobin levels within 11.0-13.0 g/dL in patients with chemotherapy-induced anemia.

An extended maintenance dosing regimen of epoetin alfa 80,000 U every 3 weeks in anemic patients with cancer receiving chemotherapy.

BACKGROUND: The purpose of this study was to evaluate the safety and efficacy of epoetin alfa (EPO) at an initial dose of 60,000 Units (U) once weekly (QW) followed by extended dosing of 80,000 U every 3 weeks (Q3W) in patients with chemotherapy-induced anemia (CIA). MATERIALS AND METHODS: Anemic patients (hemoglobin [Hb] < or = 11 g/dl) receiving Q3W chemotherapy for nonmyeloid malignancy were enrolled in this prospective, open-label, single-arm study to receive EPO 60,000 U subcutaneously (SC) QW (initial dosing phase [IDP]) until a target Hb level of 12 g/dl was reached (maximum 12 weeks). Patients who achieved an Hb level of 12 g/dl at any point during the IDP then entered the extended dosing phase (EDP; EPO 80,000 U SC Q3W). Maximum study duration (IDP + EDP) was 24 weeks. The primary endpoint was the proportion of patients achieving a hematopoietic response (Hb increase > or = 2 g/dl from baseline or Hb > or = 12 g/dl) during the IDP. RESULTS: One hundred fifteen patients were enrolled. During the IDP, 76% (84/110) of patients achieved a hematopoietic response, and 15% (17/115) received red blood cell (RBC) transfusion. Sixty-three percent (73/115) of patients entered the EDP, and 88% (64/73) of these patients maintained a mean Hb level > 11.0 and < or =13.0 g/dl. Two of 73 patients received RBC transfusion during the EDP. Adverse events were consistent with the underlying disease and chemotherapy treatment. CONCLUSION: These results suggest that initiation of EPO 60,000 U SC QW is effective in the treatment of CIA and that EPO 80,000 U SC Q3W can be an effective extended dosing option.

An extended dosing regimen of epoetin alfa 60,000 units every 2 weeks in anemic patients with cancer receiving chemotherapy.

PURPOSE: This open-label study evaluated the safety and efficacy of epoetin alfa 60,000 U once weekly Initialsly followed by 60,000 U every 2 weeks in anemic patients with cancer receiving chemotherapy. PATIENTS AND METHODS: Patients receiving weekly or every- 4-weeks chemotherapy regimens for nonmyeloid malignancy and with hemoglobin (Hb) level /= 1 dose of epoetin alfa. Sixty-eight percent of patients had hematopoietic response (Hb increase >/= 2 g/dL from baseline or Hb level >/= 12 g/dL during the IDP; primary endpoint). Eighty-four patients entered the EDP; 74 of 84 patients (88%) maintained average Hb level between 11 g/dL and 13 g/dL up to time of withdrawal or study completion. Adverse events were consistent with the underlying disease process and chemotherapy treatment. Six patients (4.7%) in the IDP and 8 patients (9.5%) in the EDP experienced clinically relevant thrombotic vascular events. CONCLUSION: In this study, approximately 90% of patients receiving an extended dosing regimen of epoetin alfa 60,000 U every 2 weeks were able to maintain Hb level between 11 g/dL and 13 g/dL.

Randomized, open-label comparison of epoetin alfa extended dosing (80 000 U Q2W) vs weekly dosing (40 000 U QW) in patients with chemotherapy-induced anemia.

OBJECTIVE: This randomized, open-label, multicenter study compared the efficacy and safety of epoetin alfa (EPO) 80 000 U every 2 weeks (Q2W) to the FDA-approved regimen of 40 000 U weekly (QW) in patients with chemotherapy-induced anemia. RESEARCH DESIGN AND METHODS: A total of 310 patients with nonmyeloid malignancy and baseline hemoglobin (Hb)

An open-label pilot study to evaluate a flexible dosing regimen of epoetin alfa for the treatment of chemotherapy-induced anemia: 60,000 units weekly followed by 60,000 units every 2 weeks.

PURPOSE: This open-label, single-arm pilot study assessed the safety and efficacy of administering an Initials epoetin alfa dose of 60,000 U subcutaneously once weekly (Initials dosing phase [IDP]) followed by an extended dose regimen of 60,000 U subcutaneously every 2 weeks (extended dosing phase [EDP]). PATIENTS AND METHODS: Patients who had a hematologic response, defined as hemoglobin (Hb) level increase >/= 1 g/dL from week 1 baseline at any time during the 4-week IDP (the primary efficacy endpoint), were eligible to enter the EDP at week 5 and receive every-other-week treatment for up to 12 additional weeks. Patients who did not exhibit this increase in the IDP were withdrawn. RESULTS: Fifty-one patients were enrolled; the mean baseline Hb level was 10.1 g/dL +/- 0.79 g/dL. Thirty-three patients (64.7%) met the primary efficacy endpoint of Hb increase >/= 1 g/dL during the IDP; 29 patients (56.9%) proceeded to the EDP. Mean Hb level at entry to the EDP was 12.4 g/dL +/- 0.99 g/dL. Further Hb increase in the EDP (average Hb level >/= week 5 Hb value) was achieved in 12 of 29 patients (41.4%). Final Hb value for patients in the EDP was 11.7 g/dL +/- 1.28 g/dL. Four patients received a total of 5 red blood cell transfusions during the study. Epoetin alfa was well tolerated and had a safety profile similar to that observed with labeled dosing. Two patients experienced a clinically relevant thrombotic vascular event. CONCLUSION: RESULTS from this pilot study suggest that higher Initials weekly dosing of epoetin alfa followed by extended dosing is safe and effective for treating chemotherapy-induced anemia.

Effectiveness of inhibition of cholesteryl ester transfer protein by JTT-705 in combination with pravastatin in type II dyslipidemia.

The inhibition of cholesteryl ester transfer protein (CETP) has recently been shown to effectively increase high-density lipoprotein (HDL) cholesterol. This study examined the use of the CETP inhibitor JTT-705 combined with pravastatin. In a randomized, double-blind, placebo-controlled trial, 155 patients with type II dyslipidemia using pravastatin 40 mg were treated with placebo or JTT-705 300 or 600 mg. Four weeks of treatment with JTT-705 600 mg led to a 30% decrease in CETP activity (p <0.001), a 28% increase in HDL cholesterol (p <0.001), and a 5% decrease in low-density lipoprotein cholesterol (p <0.03). Combination therapy using JTT-705 and pravastatin effectively increases HDL cholesterol levels and is safe and well tolerated up to 4 weeks of administration.

Extension and cleavage of the polypurine tract plus-strand primer by Ty1 reverse transcriptase.

Using hybrid RNA/DNA substrates containing the polypurine tract (PPT) plus-strand primer, we have examined the interaction between the Ty1 reverse transcriptase (RT) and the plus-strand initiation complex. We show here that, although the PPT sequence is relatively resistant to RNase H cleavage, it can be cleaved internally by the polymerase-independent RNase H activity of Ty1 RT. Alternatively, this PPT can be used to initiate plus-strand DNA synthesis. We demonstrate that cleavage at the PPT/DNA junction occurs only after at least 9 nucleotides are extended. Cleavage leaves a nick between the RNA primer and the nascent plus-strand DNA. We show that Ty1 RT has a strand displacement activity beyond a gap but that the PPT is not efficiently re-utilized in vitro for another round of DNA synthesis after a first plus-strand DNA has been synthesized and cleaved at the PPT/U3 junction.

A 5'-3' long-range interaction in Ty1 RNA controls its reverse transcription and retrotransposition.

LTR-retrotransposons are abundant components of all eukaryotic genomes and appear to be key players in their evolution. They share with retroviruses a reverse transcription step during their replication cycle. To better understand the replication of retrotransposons as well as their similarities to and differences from retroviruses, we set up an in vitro model system to examine minus-strand cDNA synthesis of the yeast Ty1 LTR-retrotransposon. Results show that the 5' and 3' ends of Ty1 genomic RNA interact through 14 nucleotide 5'-3' complementary sequences (CYC sequences). This 5'-3' base pairing results in an efficient initiation of reverse transcription in vitro. Transposition of a marked Ty1 element and Ty1 cDNA synthesis in yeast rely on the ability of the CYC sequences to base pair. This 5'-3' interaction is also supported by phylogenic analysis of all full-length Ty1 and Ty2 elements present in the Saccharomyces cerevisiae genome. These novel findings lead us to propose that circularization of the Ty1 genomic RNA controls initiation of reverse transcription and may limit reverse transcription of defective retroelements.