FDA approval summary: temsirolimus as treatment for advanced renal cell carcinoma

This report summarizes the U.S. Food and Drug Administration (FDA)'s approval of temsirolimus (Torisel), on May 30, 2007, for the treatment of advanced renal cell carcinoma (RCC). Information provided includes regulatory history, study design, study results, and literature review. A multicenter, three-arm, randomized, open-label study was conducted in previously untreated patients with poor-prognosis, advanced RCC. The study objectives were to compare overall survival (OS), progression-free survival (PFS), objective response rate, and safety in patients receiving interferon (IFN)-alpha versus those receiving temsirolimus alone or in combination with IFN-alpha. In the second planned interim analysis of the intent-to-treat population (n = 626), there was a statistically significant longer OS time in the temsirolimus (25 mg) arm than in the IFN-alpha arm (median, 10.9 months versus 7.3 months; hazard ratio [HR], 0.73; p = .0078). The combination of temsirolimus (15 mg) and IFN-alpha did not lead to a significant difference in OS compared with IFN-alpha alone. There was also a statistically significant longer PFS time for the temsirolimus (25 mg) arm than for the IFN-alpha arm (median, 5.5 months versus 3.1 months; HR, 0.66, p = .0001). Common adverse reactions reported in patients receiving temsirolimus were rash, asthenia, and mucositis. Common laboratory abnormalities were anemia, hyperglycemia, hyperlipidemia, and hypertriglyceridemia. Serious but rare cases of interstitial lung disease, bowel perforation, and acute renal failure were observed. Temsirolimus has demonstrated superiority in terms of OS and PFS over IFN-alpha and provides an additional treatment option for patients with advanced RCC.

Cyclodidemniserinol trisulfate, a sulfated serinolipid from the Palauan ascidian Didemnum guttatum that inhibits HIV-1 integrase

[structure--see text] Bioassay-guided fractionation of extracts of the Palauan ascidian Didemnum guttatum led to the isolation of cyclodidemniserinol trisulfate (1) as an inhibitor of HIV-1 integrase, which is an attractive target for anti-retroviral chemotherapy. The structure of cyclodidemniserinol trisulfate (1), the stereochemistry of which was only partially determined, was elucidated by interpretation of NMR and mass spectral data.

Dolastatin 3 and two novel cyclic peptides from a palauan collection of Lyngbya majuscula

A collection of Lyngbya majuscula from Palau contained the peptides dolastatin 3 (1), homodolastatin 3 (2), and kororamide (3), together with aplysiatoxin (4), debromoaplysiatoxin (5), and oscillatoxin A (6). The structures of the new peptides homodolastatin 3 (2) and kororamide (3) were determined by interpretation of spectroscopic data and chemical degradation.

Three-dimensional solution structure of conotoxin psi-PIIIE, an acetylcholine gated ion channel antagonist

The three-dimensional structure of conotoxin psi-PIIIE, a 24-amino acid peptide from Conus purpurascens, has been solved using two-dimensional (2D) 1H NMR spectroscopy. Conotoxin psi-PIIIE contains the same disulfide bonding pattern as the mu-conotoxins, which target skeletal muscle sodium channels, but has been shown to antagonize the acetylcholine gated cation channel through a noncompetitive mechanism. Structural information was obtained by the analysis of a series of 2D NOESY spectra as well as measurement of coupling constants from 1D 1H and PE-COSY NMR experiments. Molecular modeling calculations included the use of the distance geometry (DG) algorithm, simulated annealing techniques, and the restrained molecular dynamics method. The resulting structures are considerably similar to the previously published structures for the mu-conotoxins GIIIA and GIIIB, despite the lack of sequence conservation between conotoxin psi-PIIIE and the mu-conotoxins. The structure consists of a series of tight turns, each turn occurring in the position analogous to those of turns described in mu-GIIIA and mu-GIIIB. This suggests the disulfide bonding pattern is able to largely direct the structure of the peptides, creating a stable structural motif which allows extensive sequence substitution of non-cystine residues.

Isolation and characterization of 1,3-dimethylisoguanine from the Bermudian sponge Amphimedon viridis

The new compound 1,3-dimethylisoguanine has been isolated and characterized from the Bermudian sponge Amphimedon viridis. Chemical conversion of the natural product to theophylline and 2D NMR methods were used to determine the position of the methyl groups on the purine ring. Analysis of the mass spectral fragmentation pattern allowed assignment of the purine ring as isoguanine.

Tubercidin analogs from the ascidian Didemnum voeltzkowi

Two new 5'-deoxypyrrolo[2,3-d]pyrimidine (7-deazapurine) nucleosides, 5'-deoxytubercidin and 5'-deoxy-3-bromotubercidin, were identified from the ascidian Didemnum voeltzkowi. Two known anomers of 5'-deoxy-3-iodotubercidin were also purified from the extract. Assignments were made on the basis of 1H and 13C chemical shifts as well as HPLC-MS experiments.