SAN DIEGO--(BW HealthWire)--June 1, 1998--Vical Incorporated
(NASDAQ:VICL) released initial results today from a Phase I/II
clinical trial with Leuvectin, a potential cancer treatment, in
approximately 20 prostate cancer patients.
The trial was conducted at UCLA's Jonsson Cancer Center under the
direction of Arie Belldegrun, M.D., chief of urologic oncology and
director of urological research at the UCLA School of Medicine, and
Robert Figlin, M.D., director of clinical research at the Jonsson
Cancer Center and medical director of genitourinary oncology programs
at the UCLA Medical Center.
The data were presented at the 93rd Annual Meeting of the
American Urological Association by John Naitoh, M.D., a researcher in
the Department of Urology at UCLA and an investigator in the trial.
The trial was designed to test the safety and efficacy of
Leuvectin as a supplemental therapy for patients with tumors
apparently confined to the prostate capsule, but with a high
likelihood of metastatic disease recurrence. Treatment with Leuvectin
was intended to stimulate a localized immune response against the
primary tumor and a systemic immune response against any tumor cells
that may have escaped from the capsule.
Data measurement and analysis focused on reductions in the
patients' serum levels of prostate-specific antigen (PSA) following
treatment with Leuvectin. PSA is a biochemical substance produced
exclusively by prostate cancer cells and used as a marker to detect
and monitor the disease. Recent studies have confirmed that PSA
levels, in combination with several other factors, are highly
predictive of disease progression in post-surgical and post-radiation
patients.
Results of the trial indicated that Leuvectin was well-tolerated
and may be successful in causing a targeted immune response against
prostate cancer cells.
In five of 11 patients scheduled for radical prostatectomy
(complete removal of the prostate gland), serum PSA levels decreased
by at least 50 percent prior to surgery, and remained at undetectable
levels following surgery for up to 11 months and continuing. Two
additional patients experienced serum PSA reductions between 25
percent and 50 percent prior to surgery and undetectable levels
following surgery for up to 6 months and continuing.
In four of eight patients with recurrent disease following
radiation therapy, serum PSA levels decreased by at least 50 percent.
Three additional patients experienced serum PSA reductions between 25
percent and 50 percent.
Dr. Belldegrun observed: "Treatment with Leuvectin caused no
serious side effects, and appeared to result in measurable biological
activity. After a biopsy and injection, we would expect to see serum
PSA levels increase, but instead we have seen a surprisingly rapid
decline. We intend to refine and expand on this study," added
Belldegrun, "to provide a more complete understanding of how this
potential treatment could provide long-term benefits to patients."
Patients enrolled in the trial received two doses of Leuvectin
followed after several weeks by either surgical removal of the
prostate gland (for patients with clinically organ-confined disease)
or prostate biopsy (for patients who suffered a recurrence of the
disease after radiation therapy). PSA levels were measured prior to
treatment and continue to be monitored after the surgery or biopsy.
The trial was intended to study the safety and efficacy of Leuvectin
as a potential immunological therapy to destroy residual tumor cells
and to prevent the recurrence of prostate cancer.
Leuvectin is a DNA-based product candidate currently being
studied in renal cell carcinoma and prostate cancer. The active
ingredient in Leuvectin is a gene encoding interleukin-2 (IL-2), a
naturally occurring protein that stimulates the immune system.
Administration occurs by direct injection into a tumor, leading to
uptake by the tumor cells and subsequent expression of the IL-2
protein. The company expects local expression of IL-2 by cancer cells
may stimulate the patient's immune system to attack and destroy the
tumor cells.
Recombinant IL-2 protein is an approved anti-cancer agent for the
treatment of advanced kidney cancer and melanoma. When given
systemically, it is frequently associated with serious side effects.
Because Leuvectin delivers IL-2 locally within the tumor, it may
provide similar benefits with fewer side effects than the systemic
protein therapy.
As a result of initial Phase I/II clinical testing of Leuvectin
in several cancer indications, Vical concluded that the product
candidate appeared to be well-tolerated and successful in delivering
the IL-2 gene in a majority of patients, and may have provided
clinical benefit in certain patients.
Prostate cancer is the most frequently diagnosed type of cancer,
and the second leading cause of cancer fatalities, among men in the
United States. African Americans are at significantly greater risk
than Caucasians, and men over age 65 account for over 80 percent of
all diagnoses. More than 184,000 new cases and more than 39,000 deaths
are expected in 1998 in the U.S.
There is no curative therapy for prostate cancer once it has
escaped from the prostate capsule. While surgical therapy offers
excellent chances for cure if the disease is pathologically confined
to the gland, up to 40 percent of patients who are considered
candidates for radical prostatectomy will have adverse prognostic
factors for disease recurrence after surgery. Radiotherapy has had
varying rates of success when used in the adjuvant setting, and
hormone deprivation therapy cannot preoperatively downstage a prostate
cancer to improve rates of organ-confined disease.
Once prostate cancer has spread, androgen deprivation therapy is
very effective in controlling symptoms from metastasis, and for
slowing the rate of disease growth. However, androgen deprivation
treatment is not curative, and the majority of patients eventually
develop hormone-refractory disease. Due to the slow rate of prostate
cancer cell reproduction, the use of cytotoxic chemotherapy is
ineffective since such treatment relies on the selective killing of
actively and rapidly proliferating cells.
The treatment options available to patients who failed radiation
therapy for prostate cancer are limited. While cryotherapy and salvage
prostatectomy offer potential cures for selected patients who have
biopsy-proven local failure following radiation treatment, the salvage
treatments have been associated with low cure rates and high
complication rates. For most patients who have rising PSA levels
following radiation treatment, the only option is anti-androgen
treatment to slow the rate of cancer growth and to palliate symptoms.
Vical Inc. is focused on the development of gene-based
pharmaceutical product candidates for the prevention or treatment of
cancer, infectious diseases and metabolic disorders. A number of
therapeutic and vaccine product candidates are currently under
development by Vical and its collaborative partners, including Merck,
Pasteur Merieux Connaught, Rhone-Poulenc Rorer, Centocor and Genzyme.
Allovectin-7, which uses a lipid-DNA complex to help the immune system
recognize and attack cancer cells, is in Phase III testing in patients
with melanoma and in Phase II testing in patients with head and neck
cancer.
Leuvectin, which uses a lipid-DNA complex to stimulate an immune
response against cancer cells, is in Phase II testing in patients with
kidney cancer, and in Phase I/II testing in patients with prostate
cancer. Vaxid, a naked DNA vaccine to prevent relapse of B-cell
lymphoma, is in Phase I/II testing.
This press release contains forward-looking statements that are
subject to risks and uncertainties that could cause actual results to
differ materially from those set forth in the forward-looking
statements, including whether final results of the Phase I/II clinical
trial of Leuvectin will be favorable, whether any product candidates,
including Leuvectin, will be shown to be safe and efficacious in
clinical trials, the timing of clinical trials, whether Vical will
seek or gain approval to market any product candidates, and additional
risks set forth in the company's filings with the Securities and
Exchange Commission. Actual results may differ materially from those
projected. These forward-looking statements represent the company's
judgment as of the date of this release. The company disclaims,
however, any intent or obligation to update these forward-looking
statements.
CONTACT: Vical Incorporated
Alan R. Engbring, 619/646-1127
KEYWORD: CALIFORNIA
INDUSTRY KEYWORD: MEDICINE PHARMACEUTICALS BIOTECHNOLOGY
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