Efficacy and safety of a novel acetylcholinesterase inhibitor octohydroaminoacridine in mild-to-moderate Alzheimer's disease: a Phase II multicenter randomised controlled trial.

Background: inhibition of acetylcholinesterase (AChE) has been a effective treatment for Alzheimer's disease (AD). Octohydroaminoacridine, a new AChE inhibitor, is a potential treatment for AD. Method: we conducted a multicenter, randomised, double blind, placebo-controlled, parallel-group Phase II clinical trial to investigate the effects of octohydroaminoacridine in patients with mild-to-moderate AD. Patients were randomised to receive placebo thrice daily, octohydroaminoacridine 1 mg/thrice daily (TID) (low-dose group), 2 mg/TID (middle-dose group) or 4 mg/TID (high-dose group). Doses in the middle-dose and high-dose group were titrated over 2-4 weeks. Changes from baseline to Week 16 were assessed with the AD Assessment Scale-Cognitive Subscale (ADAS-cog), Clinician's Interview-Based Impression of Change Plus (CIBIC+), activities of daily living (ADL) and the neuropsychiatric inventory (NPI). ADAS-cog was the primary end point of the study. A two-way analysis of covariance and least squares mean t-test were used. Results: at Week 16, the changes from baseline in ADAS-cog were 1.4, -2.1, -2.2 and -4.2 for placebo, low-, middle- and high-dose groups, respectively. Patients in the high-dose group had better performance in CIBIC+ and ADL scores at the end of the study. There was no significant difference in the change in NPI score among the groups. The effects of octohydroaminoacridine were dose dependent, and were effective within 16 weeks of treatment. No evidence was found for more adverse events that occurred in different drug groups than placebo group. Conclusions: octohydroaminoacridine significantly improved cognitive function and behaviour in patients with mild-to-moderate AD and this effect was dose dependent.

Cytotoxicity and mutagenicity of frameshift-inducing agent ICR191 in mismatch repair-deficient colon cancer cells.

BACKGROUND: Deficiency of DNA mismatch repair is a common feature of cancers exhibiting instability of microsatellite DNA sequences. Cancers with microsatellite instability are recognizable by their high rate of spontaneous frameshift mutations within microsatellite sequences, their resistance to killing by cytotoxic agents, and their localization to specific tissues, e.g., the proximal colon and stomach. We hypothesized that the mismatch repair deficiency of these cancers would make them vulnerable to environmental or chemical frameshift-inducing agents. This study was undertaken to test whether exogenous frameshift-inducing agents selectively induce mutations in mismatch repair-deficient cells of mutagen-exposed tissues like the colon and whether cytotoxic doses of these agents would preferentially kill those cells. METHODS: Cytotoxicity of the acridine mutagen 6-chloro-9-[3-(2-chloroethylamino)propylamino]-2-methoxy-acridine (ICR191), a DNA frameshift inducer, was determined in the mismatch repair-deficient human colon carcinoma cell line HCT116 versus the repair-reconstituted derivative HCT116+C3. Vulnerability to the mutagenic effects of ICR191 was determined by transfection of HCT116 or HCT116+C3 cells with a frameshift reporter vector, followed by treatment of the cells with ICR191. Alternatively, the reporter vector was reacted ex vivo with ICR191, and the derivatized vector was then transfected into HCT116 or HCT116+C3 cells. RESULTS: ICR191 proved to be fivefold to 10-fold more potent in inducing mutations in mismatch repair-deficient HCT116 cells than in mismatch repair-proficient HCT116+C3 cells. Moreover, at cytotoxic doses of ICR191, repair-deficient HCT116 cells proved to be fivefold more vulnerable to killing than did HCT116+C3 cells. CONCLUSIONS: Frameshift-inducing mutagens can selectively induce mutations in mismatch repair-deficient cells versus mismatch repair-proficient cells. Environmental exposures may, therefore, favor development of cancers with microsatellite instability in tissues like the gut. Frameshift-inducing agents can, however, also preferentially kill mismatch repair-deficient cancer cells and, thus, may be promising as model therapeutic compounds.

Phase I clinical and pharmacokinetic study of 4'-(9-acridinylamino)-methanesulfon-m-anisidide in children with cancer.

Forty-one pediatric patients with advanced cancer (24 with acute leukemia and 17 with diverse solid tumors) received 74 courses of therapy with a new chemotherapeutic agent, 4'-(9-acridinylamino)methanesulfon-m-anisidide (AMSA: NSC 249992). Treatments were given by slow i.v. injection daily for five days every two to three weeks. In patients with leukemia: (a) dosages were escalated from 1.3 to 150 mg/sq m/day; (b) toxicity in the form of stomatitis, vomiting, and phlebitis occurred at dosage levels of 125 to 150 mg/sq m/day; and (c) oncolytic effects were observed in 13 of 24 patients. In patients with solid tumors: (a) dosages were escalated from 5 to 50 mg/sq m/day; (b) toxicity (stomatitis, myelosuppression, and phlebitis) occurred at the dosage level of 50 mg/sq m/day; and (c) no oncolytic responses were noted. Serum concentrations of total and free AMSA were assayed by a fluorescence technique and declined in a biphasic manner with free AMSA declining more rapidly than total AMSA. Dosages of greater than 100 mg/sq m/day were required to maintain serum concentrations of total and free AMSA greater than 0.2 microM for the entire five-day schedule. The results suggest that maximum tolerated dosages of AMSA may differ in children with leukemia and solid tumors; however, hematopoietic toxicity could not be fully evaluated in the patients with leukemia. AMSA has clear antileukemic activity that warrants future Phase II trials.

Enhancement of frameshift mutagenesis in Salmonella typhimurium derivatives of hisC3076 by 5-azacytidine and other agents.

The yield of frameshift revertants of Salmonella typhimurium strain hisC3076 on plates containing the mutagen 9-aminoacridine (9AA) is enhanced by the addition to the selection medium of a number of chemical agents. These include 5-azacytidine (5-azaC), naladixic acid, ethyl methanesulphonate; pre-treatment of cells with u.v. light or gamma-radiation is also effective. With the exception of u.v. which is detected as a poor mutagen in strain hisC3076, all other enhancing agents are not usually detected as mutagens in this strain. The observed synergism between 9AA and 5-azaC in recA and uvrB derivatives of hisC3076 eliminates the possibility that recA-dependent repair or excision repair is necessary. However a lack of synergism in a uvrD derivative suggests that helicase II is involved. It is suggested that the presence of 9AA in the plating medium enables the synergistic agents to be detected as mutagens.

Temporary effects of AMSA (4'-(9-acridinylamino) methanesulfon-m-anisidide) chemotherapy on spermatogenesis.

Spermatogenesis in a melanoma patient treated with 12 courses of acridinyl anisidide (AMSA) (20 mg/m2/course) was studied by monitoring sperm concentration, motility, and morphology at various phases of treatment. Chemotherapy was interrupted for 20 weeks between the ninth and tenth course. Sperm concentration and motility began to decline after the second course. At the third course, the percentage of morphologic abnormalities had increased to 86.5% from a pretreatment value of 57.8% (P less than 0.001). Azoospermia was observed at the sixth course and persisted until 12 weeks after the ninth course, when semen levels returned to pretreatment levels: 20 million/ml; 70% motility; 60.1% abnormal forms. Three weeks after the 12th course, the sperm count was reduced to 250,000/ml, motility to 5%, and abnormalities increased to 84.0%. The rapid recovery of normal spermatogenesis observed during the chemotherapy interruption indicates that AMSA has only a temporary, reversible effect on differentiating germinal cells with no toxicity to stem cells.