Oxidation of Thioether Ligands in Pseudotetrahedral Cyclopentadienylruthenium Complexes: Toward a New Stereoselective Synthesis of Chiral Sulfoxides(1).

Ionic ruthenium thioether complexes [Cp(LL')Ru(SRR')]PF(6) (LL' = Ph(2)PCH(2)PPh(2) (1), Ph(2)PC(2)H(4)PPh(2) (2), (Ph(3)P, CO) (3), Me(2)PC(2)H(4)PPh(2) (4), (S,S)-Ph(2)PCHMeCHMePPh(2) (5), SRR' = MeSPh (a), MeS-i-Pr (b), MeSBz (c), i-PrSBz (d), EtSBz (e), MeSCy (f), SC(4)H(8) (g)) were synthesized from the corresponding chloro complexes [Cp(LL')RuCl] and thioethers. 5a crystallized in the orthorhombic system, space group P2(1)2(1)2(1) (No. 19), with a = 11.269(3) Å, b = 15.104(2) Å, c = 23.177(4) Å, and Z = 4. 5b crystallized in the monoclinic system, space group P2(1) (No. 4), with a = 10.539(5) Å, b = 16.216(9) Å, c = 11.011(8) Å, beta = 106.04(2) degrees, and Z = 2. A similar ligand exchange reaction yielded the analogous sulfoxide complexes [Cp(LL')Ru(S(O)RR')]PF(6) (6-10). 10a crystallized in the orthorhombic system, space group P2(1)2(1)2(1) (No. 19), with a = 14.1664(13) Å, b = 15.792(2) Å, c = 17.641(2) Å, and Z = 4. 10b.0.93CH(2)Cl(2) crystallized in the orthorhombic system, space group P2(1)2(1)2(1) (No. 19), with a = 12.069(2) Å, b = 17.379(2) Å, c = 19.760(5) Å, and Z = 4. The thioether complexes can also be directly converted to sulfoxide complexes with the strong oxygen transfer reagent dimethyldioxirane (DMD). No crossover products are formed when mixtures of two thioether complexes (e.g., 1a/2c or 1c/2a) are treated with DMD, demonstrating that no Ru-S bond cleavage is involved. Moderate diastereoselectivities are observed for the oxygen transfer to chiral, racemic thioether complexes 3 (8-28%) and 4 (34-60%). Oxidation of the (S,S)-CHIRAPHOS complexes 5, however, is highly stereoselective (de = 46-98%). Treatment of the sulfoxide complexes 10 with sodium iodide removes the chiral, nonracemic sulfoxides from the metal with retention of the configuration at sulfur.

Multipeptide immune response to cancer vaccine IMA901 after single-dose cyclophosphamide associates with longer patient survival.

IMA901 is the first therapeutic vaccine for renal cell cancer (RCC) consisting of multiple tumor-associated peptides (TUMAPs) confirmed to be naturally presented in human cancer tissue. We treated a total of 96 human leukocyte antigen A (HLA-A)*02(+) subjects with advanced RCC with IMA901 in two consecutive studies. In the phase 1 study, the T cell responses of the patients to multiple TUMAPs were associated with better disease control and lower numbers of prevaccine forkhead box P3 (FOXP3)(+) regulatory T (T(reg)) cells. The randomized phase 2 trial showed that a single dose of cyclophosphamide reduced the number of T(reg) cells and confirmed that immune responses to multiple TUMAPs were associated with longer overall survival. Furthermore, among six predefined populations of myeloid-derived suppressor cells, two were prognostic for overall survival, and among over 300 serum biomarkers, we identified apolipoprotein A-I (APOA1) and chemokine (C-C motif) ligand 17 (CCL17) as being predictive for both immune response to IMA901 and overall survival. A randomized phase 3 study to determine the clinical benefit of treatment with IMA901 is ongoing.

Immunogenicity and safety of a novel therapeutic hepatitis C virus (HCV) peptide vaccine: a randomized, placebo controlled trial for dose optimization in 128 healthy subjects.

As interferon/ribavirin-based standard therapy is curative in only about half of HCV patients, there remains an important need for alternatives including vaccines. The novel peptide vaccine IC41 consists of five synthetic peptides harboring HCV T cell epitopes and poly-L-arginine as synthetic adjuvant. In this randomized, placebo-controlled trial, 128 HLA-A2 positive healthy volunteers received four s.c. vaccinations of seven different doses IC41, HCV peptides alone, poly-l-arginine alone or saline solution, every 4 weeks. IC41 was safe and well tolerated. Mild to moderate local reactions were transient. Immunogenicity was assessed using T cell epitope specific [3H]-thymidine proliferation, IFN-gamma ELIspot and HLA-tetramer assays. IC41 induced responses in all dose groups. Higher responder rates were recorded in higher dose groups and increasing number of vaccinations were associated with higher responder rates and more robust responses. Poly-L-arginine was required for the aimed-for Th1/Tc1-type immunity (IFN-gamma secreting T cells).