Provenge(R)) targeting prostatic acid phosphatase can induce durable
remission of metastatic androgen-independent prostate cancer: A phase 2
trial"

Antigen presenting cells (APC)8015 loaded with PA2024, a recombinant
fusion protein containing prostatic acid phosphatase and GM-CSF, are
generally well tolerated and adverse effects are manageable, according
to a new study from the Mayo Clinic.
"Along with manageable adverse effects, we observed a definite clinical
response," report Patrick A. Burch, MD, Division of Medical Oncology,
Mayo Clinic, Rochester, Minnesota, United States, and colleagues.
The authors enrolled 21 patients with androgen-independent prostate
cancer in a phase 2 trial to determine the effects of APC8015
(autologous antigen presenting cells incubated in the presence of
PA2024, a recombinant prostatic acid phosphatase (PAP) with GM-CSF,)
followed by injections of soluble PA2024.
Each patient received 2 infusions, 2 weeks apart of APC8015. Two weeks
after the second infusion the patients received 3 subcutaneous
injections of 1.0 mg of PA2024 1 month apart.
The disease progressed before the first PA2024 injection at week 4 in 2
patients, after the first injection in 1 patient, and after the second
injection at week 8 for 3 patients. The remaining 15 patients received
all 3 PA2024 injections and remained on study until at least week 16.
Nineteen patients who had received both infusions of APC8015 and at
least 1 injection of PA2024 could be evaluated for response to
treatment. The median time to progression for these patients was 118
days from the date of registration.
Two patients showed a 25% to 50% transient decrease in prostatic
specific antigen (PSA). For a third, the level of PSA rose from 221
ng/mL at baseline to 251 ng/mL by week 4 and then dropped to
undetectable levels by week 24. "His PSA level has remained undetectable
for 52 months after beginning of treatment and the metastatic adenopathy
has resolved," the authors report.
The most frequent adverse events after APC8015 infusion were National
Cancer Institute Common Toxicity Criteria (NCI-CTC) grade 1-2 chills and
fatigue. Nineteen percent of patients reported severe grade 3-4 adverse
events including 1 episode each of chills, fatigue, fever, malaise,
tachycardia, dyspnoea, and vomiting after infusion of AP8015.
Twenty-four percent of patients had grade 1-2 local reactions after
subcutaneous injections of PA2024.
Response to PA2024 was evaluated in 15 patients every 4 weeks from week
0 to week 16 and then every 8 weeks until disease progression. It was
significant at week 4 (P < .0001) and persisted for the duration of
monitoring.
"Our evidence that this mode of treatment is clinically active and
accompanied by manageable adverse effects complements the evidence
obtained at the University of California, San Francisco in a study of
APC8015 alone," the authors concluded. Consequently, we are currently
conducting a multicentre, randomised phase 3 trial of APC8015 alone for
the treatment of patients with asymptomatic, radiographically evaluable,
androgen-independent prostate carcinoma."

knowledge is power - growing old is mandatory - growing wise is optional    
"Many more men die with prostate cancer than of it. Growing old is
invariably fatal. Prostate cancer is only sometimes so."