SAN FRANCISCO _ Ligand Pharmaceuticals Inc. is taking its firstretinoid-based drug into Phase III trials as a treatment for cutaneousKaposi's sarcoma in AIDS patients.
The compound, a synthetic version of 9-cis-retinoic acid, will be thefirst topical treatment tested for Kaposi's sarcoma in an advancedclinical study.
The drug is being developed under a joint venture between Ligand, ofSan Diego, and Allergan Inc., of Irvine, Calif. The two formed apublicly held company, Allergan Ligand Retinoid Therapeutics Inc.(ALRT), in December 1994 to fund research on retinoid drugs. Thecompound, called ALRT 1057, represents Ligand's most advanceddrug candidate.
Progression to the pivotal Phase III studies followed positive resultsfrom Phase I/II trials involving AIDS patients. Ligand officials saidthey will discuss the advanced trials and data from earlier clinicalstudies today at Hambrecht & Quist Inc.'s 14th Annual Health CareConference in San Francisco.
Robert Stein, Ligand's chief scientific officer, said development ofALRT 1057 is on track for submission of a new drug application withthe FDA by 1997.
"This would be the first product from our own research to becomeregistered," Stein said.
ALRT 1057 is being studied in topical and oral forms in numerousclinical trials. In addition to Kaposi's sarcoma, the compound istargeted for other cancers, such as kidney cancer, acutepromyelocytic leukemia and multiple myeloma.
Interim results of Phase I/II trials of ALRT 1057 revealed that 30percent of the first 43 AIDS patients enrolled in the study withcutaneous Kaposi's sarcoma experienced reductions in lesions treatedwith the drug. Each patient had several lesions treated with ALRT1057 while other lesions were left untreated as part of a controlgroup. Only four of the 43 patients saw reductions in untreatedlesions during the study period. A total of 78 patients participated inthe studies.
Trial data also was to be released today on another topical retinoidcompound, called Targretin, which is being developed by Ligandindependent of the ALRT joint venture. Results of the Phase I/IIstudy for cutaneous T cell lymphoma showed 33 percent of the 27patients evaluated saw a positive response to the treatment. Targretinalso is being developed in topical and oral forms.
Both ALRT 1057 and Targretin (LGD 1069) are derived fromretinoids, which are naturally occurring hormones chemically relatedto vitamin A and are known to affect cell activities through binding tointracellular receptors.
ALRT 1057 binds to six intracellular receptor types, which aredivided into two subfamilies of three each called RARs and RXRs.Targretin is a synthetic compound designed to bind only to RXRs.
Targretin, in a topical form, also was evaluated in a Phase I/II trialfor cutaneous Kaposi's sarcoma in AIDS patients. In those studies,15 percent of 46 patients experienced reductions in lesions.
Oral forms of both ALRT 1057 and Targretin are being tested inPhase II studies for visceral manifestations of Kaposi's sarcoma. n
-- Charles Craig
(c) 1997 American Health Consultants. All rights reserved.