A phase II study of the Ras-MAPK signaling pathway inhibitor TLN-4601 in patients with glioblastoma at first progression.

This phase II trial was undertaken to evaluate the efficacy of TLN-4601 in patients with glioblastoma (GBM) at first progression. TLN-4601 inhibits the Ras-MAPK signaling pathway, and in animal models crosses the blood-brain barrier and accumulates in implanted gliomas, possibly by binding specifically to the peripheral benzodiazepine receptor. A maximum of 40 patients with recurrent GBM were to be enrolled in this study. TLN-4601 was administered at a dose of 480 mg/m(2)/day by continuous intravenous (CIV) administration. Each 21-day cycle consisted of a 14-day CIV administration and a 7-day recovery period. Samples were obtained from all patients for pharmacokinetic evaluations (PK) and for Raf-1 and pERK biomarker assessment using immunohistochemistry and flow cytometry. Following enrollment of 20 patients, this study was terminated due to a lack of efficacy. Of 17 evaluable patients, 14 had MR scans performed after two cycles of TLN-4601. Of these 14 patients, three had stable disease and 11 had disease progression. Only three patients had MR scans performed after four cycles and all had evidence of radiographic progression. Serum PKs confirmed that patients were exposed to TLN-4601 at targeted drug levels. TLN-4601 was generally well tolerated although two patients discontinued treatment due to adverse events. Biomarker analysis did not show consistent changes. TLN-4601 infused via CIV at 480 mg/m(2)/day for 14 of 21 days is well tolerated by patients with progressive GBM. However, this agent is ineffective in progressive GBM when administered as monotherapy in this schedule.

Treatment of typical (enteropathic) hemolytic uremic syndrome.

Typical enteropathic HUS (eHUS) is triggered by Shiga toxin (Stx)-producing bacteria (STPB), predominantly Stx-producing ESCHERICHIA COLI O157. The cell biological aspects of Stx have been well defined, but host factors potentially predisposing to the development or severity of HUS remain elusive. Treatment of eHUS includes supportive measures and invasive extracorporeal therapies. Thirty to 60% of children with eHUS require dialysis. Peritoneal and hemodialysis appear equally effective. Patient age, center experience, and equipment availability determine the choice of the modality; circulatory instability may require continuous renal replacement therapies. At present, no evidence indicates that plasma infusion or exchange therapies improve outcome of Stx-induced HUS. However, the traditional separation between diarrhea-positive (D (+)) and negative (D (-)) HUS, implying two entirely different pathological pathways, requires a fresh look: Atypical HUS may follow nonspecific diarrhea, and, conversely, STPB and fecal Stx may not be detected anymore at the time of the diagnosis of HUS. Recently, Stx has been found to directly interfere with the alternative complement pathway regulator factor H in vitro, whereas some patients with Stx-HUS demonstrate evidence of complement activation. Among newer treatments for eHUS, development of Stx-neutralizing monoclonal antibodies is the most advanced. This review concludes with a discussion of the rationale, mode of action, and status of presently available therapeutic antibodies against Stx2 and Stx1.