Tamibarotene eradicates advanced-stage leukemia

CytRx announces that an advanced form of acute promyelocytic leukemia, or APL, has been eradicated in former NBA player Ray Johnston following treatment with CytRx’s experimental cancer drug tamibarotene.

Johnston was afflicted with a particularly aggressive type of APL called chloromas and had previously failed other approved therapies. More than 30 tumors were detected throughout his body prior to treatment with tamibarotene, which was administered in tablet form on a compassionate use protocol.

“Following four months of treatment with tamibarotene, the disease was totally eliminated,” said Johnston. “In January, my PET scan showed a significant decrease in the disease, and in April it confirmed that the leukemia was completely gone. Last week marked my six-month anniversary of being cancer-free.”

Johnston will continue taking orally administered tamibarotene every other month as an added measure given his history of relapses.

Johnston, 31, was diagnosed with APL six years ago, ending his brief career as a Dallas Maverick. He previously was treated with FDA-approved therapies for APL, as well as with a blood stem cell transplant. He has experienced several remissions of his leukemia, but has always relapsed.

In December 2009, his physician, Dr Robert Collins at the University of Texas Southwestern Medical Center, requested tamibarotene from CytRx on a compassionate use basis, and the request was granted.

“We wanted to give tamibarotene a try for Ray given the fact that his APL has relapsed several times following treatment with all trans-retinoic acid (ATRA), anthracycline chemotherapy and arsenic trioxide (ATO), the current first- and second-line therapies. There currently is no approved third-line therapy for APL,” said Dr Collins.

CytRx is conducting the phase two STAR-1 registration trial under a Special Protocol Assessment to evaluate the efficacy and safety of tamibarotene in patients with third-line APL. In Japan, tamibarotene was approved in 2005 and is marketed for the treatment of second-line APL.

“I’ve regained my life following treatment with tamibarotene,” added Johnson. “It is the best I have felt since I joined the Dallas Mavericks.” Following his diagnosis, Johnston formed the band: The Ray Johnston Band, and has been featured on Dallas Mavericks’ owner Mark Cuban’s HDNet reality series – The Ray Johnston Band Road Diaries. Currently, the Ray Johnston Band is on tour in North America and has opened for Jimmy Buffet, The Cure, The Fray, and Los Lonely Boys, all internationally renowned performers.

Recently, CytRx announced that a 44-year-old female patient with advanced APL showed no evidence of disease in the blood cells and/or bone marrow following treatment with tamibarotene. This patient is enrolled in CytRx's phase two STAR-1 registration trial, which is evaluating the efficacy and safety of this drug candidate as a third-line treatment for APL.

She is one of three previously reported advanced APL patients to achieve a hematologic complete response with tamibarotene treatment in the STAR-1 trial. A detailed report of this patient, who also had failed first- and second-line APL treatments as well as a bone marrow transplant, was published in the July online issue of the peer-reviewed British Journal of Haematology with publication in the print edition expected later this year.

Steven A Kriegsman, CytRx president and CEO, said, “We are thrilled with Ray’s response to tamibarotene. As important, we are highly encouraged about tamibarotene’s prospects now that several patients afflicted with advanced APL who have failed multiple other treatments are reporting total elimination of this disease with our drug."

"We estimate tamibarotene’s market opportunity in refractory APL in the US alone to approach US$20 million annually and, with an expanded label to include refractory, maintenance and front-line therapy, to increase to US$150 million annually in the US and Europe. Furthermore, in order to reach blockbuster status, we are evaluating the development of tamibarotene in other deadly cancers with large market opportunities.”