OK432 versus doxycycline for treatment of macrocystic lymphatic malformations.

OBJECTIVES: A variety of sclerotherapy agents are used to treat macrocystic lymphatic malformations (LMs). This retrospective study at a single institution was performed to compare the outcomes of pediatric macrocystic LMs of the head and neck that were treated with doxycycline or with OK432. METHODS: The outcomes measured included early response to therapy, number of treatments required, operating room time, and adverse events. RESULTS: The rates of clinical success for OK432 and doxycycline were similar (83% and 82%, respectively; p > 0.05), although OK432-treated patients required more treatments than did doxycycline-treated patients (1.9 versus 1.0 injections; p = 0.01; 95% confidence interval, 1.57 to 0.27). The average operating room time for a single OK432 injection was significantly shorter than that for doxycycline (53.2 versus 98.1 minutes; p < 0.001); however, when the total number of treatments administered was considered, the overall times in the operating room were similar. Adverse events in the early postoperative period were more common in OK432-treated patients, who experienced marked postoperative swelling compared to doxycycline-treated patients. CONCLUSIONS: OK432 and doxycycline are both effective sclerosants for the treatment of predominantly macrocystic LMs. The administration time for OK432 is shorter than that for doxycycline, but OK432 required more treatments overall to achieve clinical success. Early adverse events were more common in OK432-treated patients, but longer follow-up is necessary to determine whether rates of recurrence and adverse events are similar, particularly in light of the risk of tooth discoloration in doxycycline-treated patients.

Cytostatic versus cytocidal activities of chloroquine analogues and inhibition of hemozoin crystal growth.

We report an improved, nonhazardous, high-throughput assay for in vitro quantification of antimalarial drug inhibition of ß-hematin (hemozoin) crystallization performed under conditions that are more physiological relative to previous assays. The assay uses the differential detergent solubility of crystalline and noncrystalline forms of heme and is optimized via the use of lipid catalyst. Using this assay, we quantify the effect of pH on the crystal growth-inhibitory activities of current quinoline antimalarials, evaluate the catalytic efficiencies of different lipids, and test for a possible correlation between hemozoin inhibition by drugs versus their antiplasmodial activity. Consistent with several previous reports, we found a good correlation between hemozoin inhibition potency versus cytostatic antiplasmodial potency (50% inhibitory concentration) for a series of chloroquine (CQ) analogues. However, we found no correlation between hemozoin inhibition potency and cytocidal antiplasmodial potency (50% lethal dose) for the same drugs, suggesting that cellular targets for these two layers of 4-aminoquinoline drug activity differ. This important concept is also explored further for QN and its stereoisomers in the accompanying paper (A. P. Gorka, K. S. Sherlach, A. C. de Dios, and P. D. Roepe, Antimicrob. Agents Chemother. 57:365-374, 2013).