Protein Design Laboratories Inc. (PDL) onWednesday confirmed some analysts'speculation that its Smart Anti-Tac Antibody ismidway through a Phase II/III trial for theprevention of graft-versus-host disease (GvHD),and has begun a trial in kidney transplantationpatients.Hoffman-La Roche Inc., which licensedworldwide development and manufacturing rightsto Smart Anti-Tac in 1989, has enrolled abouthalf of the patients for the trial, and expects tocomplete accrual later this year. PDL'scommunications director, Peter Dworkin, saidthe patient enrollment number would remainundisclosed.The GvHD trial began in April 1993 and is beingconducted in the U.S., Canada and fourEuropean countries. GvHD is a complication thatcan occur in patients undergoing allogeneic bonemarrow transplantation.In an earlier trial sponsored by the NationalInstitutes of Health at Harvard Medical School,40 kidney transplant patients received theoriginal mouse anti-Tac antibody from whichSmart Anti-Tac, a human antibody, was derived.Treatment appeared to diminish the frequency ofacute transplant rejection but elicited a humananti-mouse antibody (HAMA) immune responsethat restricted treatment to a two-week period. "Itwas on that basis that we licensed that antibodyand humanized it," Dworkin said.Single Dose Didn't Cause HAMAIn a previously released Phase I study, a singledose of the Smart Anti-Tac Antibody did notcause a HAMA response and showedindications of activity in 10 of 24 acute steroid-resistant GvHD patients, PDL of Mountain View,Calif., said.Smart Anti-Tac combines a small part of themouse anti-Tac antibody with about 90 percentof a human antibody.Vertex Pharmaceuticals Inc. has begun a PhaseII clinical trial with VX-105 for the treatment ofbeta thalassemia, a hemoglobin disorder. Thestudy, conducted under an Investigational NewDrug application, is part of a planned multicenterstudy in the U.S. and Canada, the Cambridge,Mass., company said.The trial is a pharmacokinetic safety and efficacystudy of continuous and intermittent infusions ofVX-105 in patients with beta thalassemiaintermedia. The drug is delivered intravenouslyand reactivates a gene for the production of thefetal hemoglobin gene which is normallyturned off after infancy by administration ofarginine butyrate, a naturally occurring fatty acid.Studies have indicated that presence of the genecan help alleviate symptoms in certain patients.Last summer Vertex licensed arginine butyrate(and related compounds) from Children'sHospital Oakland, and acquired exclusiveworldwide rights to develop, manufacture andmarket compounds to treat hemoglobindisorders.Joshua Boger, Vertex's president and chiefexecutive officer, said the company plans toexpand the clinical program to include sickle cellanemia patients in a separate set of trials in theU.S. and begin clinical studies with VX-105 inEurope later this year.Pilot Trial Set for Dermagraft-TCThe FDA approved an Investigational DeviceExemption filed by Advanced Tissue SciencesInc. to begin a pilot clinical trial of Dermagraft-Transitional Covering, a living dermal tissuecombined with a temporary synthetic epidermallayer.The La Jolla, Calif., company said it will startenrolling patients for the trial at the end of theweek. Ten patients will be enrolled and followedfor 12 weeks.The Dermagraft-TC is designed to serve as aprotective cover to help severely burned patientsretain fluids and prevent infection until enough ofthe patient's own skin is available for grafting.Human Trials for Genital Warts TreatmentBeginsGilead Sciences Inc. has begun Phase I/IIhuman clinical testing of a topical formulation ofits drug candidate, GS 504, for genital wartscaused by the human papillomavirus, in patientswith HIV infection.The Foster City, Calif., company said the firstpatient in the dose-escalation study is beingenrolled at the University of Washington.Results of Gilead's Phase I/II trials of GS 504,known as HPMPC, in AIDS patients withasymptomatic cytomegalovirus (CMV) infectiondemonstrated anti-CMV activity with intravenousdosing only once per week, or less often. Thisstudy will evaluate safety of GS 504 appliedonce daily.
-- Jim Shrine
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