* Viral load decreased in three of six trial patients
* Virus undetectable in one patient
* Details of development strategy expected on Wednesday
* Sangamo CEO has no plans for HIV treatment partnership
By Deena Beasley
Sept 18 An early stage trial of Sangamo
BioSciences Inc's (SGMO.O) HIV treatment found that the gene
therapy reduced levels of the virus and even eliminated it in
one patient with a naturally occurring gene mutation.
The very small Phase 1 trial tested the SB-728-T gene
therapy, which is designed to disrupt the CCR5 gene used by HIV
to infect cells of the immune system.
If shown to be safe and effective, the treatment could end
the need for the antiretroviral drugs now used to keep the
virus that causes AIDS in check by suppressing viral
replication in the blood.
Trial results presented in Chicago on Sunday at the
Interscience Conference on Antimicrobial Agents and
Chemotherapy show a "statistically significant relationship
between estimated modification of both copies of the CCR5 gene
and viral load," said Dr. Carl June, trial investigator and
director of translational research at the University of
Pennsylvania's cancer research institute.
In a statement, June said the results suggest the need to
increase the frequency of the modified cells in HIV-infected
patients, which could lead to a "functional cure" for AIDS, but
the means of achieving this have not been clarified.
Sangamo said earlier this year that a single infusion of
the treatment improved immune system damage in nearly all of
the subjects analyzed in the first trial of the therapy in
The 10 patients in the trial were on antiretroviral therapy
when the study began. After four weeks, six of them went on a
"treatment interruption," during which they stopped taking
antiviral medication for 12 weeks.
Viral load decreased in three of the six subjects, with one
patient's viral load reduced to undetectable levels. That
patient carried a naturally occurring mutation in one copy of
his CCR5 gene.
Humans contain two copies of each gene, one from the father
and one from the mother, which sometimes are referred to as the
alleles of a gene.
"Since one copy of his gene was already disrupted
naturally, twice as many of his cells were 'biallelically'
modified," Sangamo Chief Executive Officer Edward Lanphier said
in a telephone interview, meaning that both members of the CCR5
gene pair were knocked out.
He estimated that between 5 percent and 10 percent of HIV
patients carry the genetic mutation.
Around 33 million people worldwide have the human
immunodeficiency virus (HIV) that causes AIDS. Major producers
of current HIV drugs include Gilead Sciences (GILD.O) and
Lanphier said Sangamo will move ahead with a strategy to
maximize the number of cells that can be "biallelically"
modified by SB-728-T. Options include targeting only the small
segment of patients with mutated CCR5 genes or using
"strategies that boost the amount of engraftment of modified
The CEO said he plans to unveil details of Sangamo's plans
at an investment banking conference in New York on Wednesday.
Lanphier emphasized that the company intends to take the
HIV treatment into mid-stage trials without a partner.
"We have more than sufficient cash to push forward into
Phase 2 trials," he said, reaffirming that Sangamo expects to
have cash holdings of at least $85 million at year-end.
(Reporting by Deena Beasley in Los Angeles)