This presentation from American Society of Clinical Oncology in Medpage Today reports outcome from a study exploring ability of estrogen therapy to replace androgen lowering treatments without some of the side effects.
ORLANDO, March 3 -- Estrogen could make a comeback as hormonal therapy for advanced prostate cancer if interim results from an ongoing clinical trial hold up in further testing.
Transdermal estrogen drove down testosterone and PSA levels to a similar extent as an LHRH analog, Ruth E. Langley, M.D., of the Medical Research Council in London, reported at the Genitourinary Cancers Symposium.
No worrisome adverse events have occurred with the estrogen patches, which could help preserve bone mineral density, unlike conventional androgen deprivation therapy.
"These data demonstrate that estrogen patches produce a similar fall in testosterone to LHRH analogs and concomitant falls in PSA in patients with metastatic and locally advanced prostate cancer," said Dr. Langley. "The patches have been generally well tolerated."
Cardiovascular safety data have yet to be released, pending accrual of the 200-patient total for the study.
Nonetheless, on the basis of the results, the data monitoring committee recommended that investigators "focus their plans towards developing a larger, phase III trial," said Dr. Langley.
Oral estrogen won support as hormonal therapy for prostate cancer in the 1960s. However, the treatment fell out of favor because it was associated with increased cardiovascular morbidity, said Dr. Langley.
"The [cardiovascular] toxicity has been attributed to first-pass hepatic metabolism, which affects lipids and coagulation proteins," she said. "Since transcutaneous administration of estrogen avoids the enterohepatic circulation, it should not be associated with the same high levels of cardiovascular toxicity."
In a preliminary trial involving 20 patients with prostate cancer, estrogen patches lowered testosterone to castrate levels and caused no cardiovascular events, aside from one case of edema.
On the basis of those results, investigators organized a multicenter, randomized study that included 172 patients as of mid-February.
The trial involved patients with newly diagnosed T3/4 prostate cancer or with cancer in PSA relapse following definitive surgery or radiation therapy. Castrate-level testosterone was defined as 50 ng/dL.
The patients were randomized 1:2 to an LHRH analog or to transdermal patches that released 100 µg of estradiol per hour. After a planned review of data, investigators increased the patch dosage.
As a result, the first 33 patients randomized to transdermal patches received three patches, which were changed twice weekly. The remaining patients assigned to the estrogen group received four patches that were changed twice weekly.
Estradiol, testosterone, and PSA levels were measured at four weeks and three months and then every six months. In addition, investigators measured PSA levels at nine, 15, and 21 months.
At week four, 20 of 33 patients (60.6%) in the LHRH analog group had castrate levels of testosterone, as did 20 of 30 (66.6%) who received three estradiol patches, and 30 of 33 (90.9%)who received four patches.
Four LHRH analog patients had testosterone levels between 50 and 100 ng/dL, compared with five in the three-patch group and three in the four-patch group.
By week 12, 26 of 28 evaluable patients (92.8%) assigned to the LHRH analog had castrate levels of testosterone, and none had levels between 50 and 100 ng/dL.
Among patients treated with three estradiol patches, 21 of 29 (72.4%) had castrate levels of testosterone and six had levels of 50 to 100 ng/dL.
In the four-patch group, 27 of 31 patients (87%) had castrate testosterone levels and the other four had levels of 50 to 100 ng/dL.
At six months, the median testosterone levels were 14.3 ng/dL in the LHRH analog group, 28.6 ng/dL in the three-patch group, and 22.9 ng/dL in the four-patch group.
Median PSA values were 0.9 ng/mL, 3.2 ng/mL, and 1.3 ng/mL, respectively.
Dr. Langley and her coinvestigators reported no disclosures.
By Charles Bankhead, Staff Writer, MedPage Today
Published: March 03, 2009
Primary source: ASCO: Genitourinary Cancers Symposium
Source reference:
Langley RE, et al "PATCH, a randomized phase II trial of estrogen patches versus LHRH as first-line hormonal therapy for prostate cancer: planned interim analysis results" ASCO: GU 2009; Abstract 173.
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ORLANDO, March 3 -- Estrogen could make a comeback as hormonal therapy for advanced prostate cancer if interim results from an ongoing clinical trial hold up in further testing.
Transdermal estrogen drove down testosterone and PSA levels to a similar extent as an LHRH analog, Ruth E. Langley, M.D., of the Medical Research Council in London, reported at the Genitourinary Cancers Symposium.
No worrisome adverse events have occurred with the estrogen patches, which could help preserve bone mineral density, unlike conventional androgen deprivation therapy.
"These data demonstrate that estrogen patches produce a similar fall in testosterone to LHRH analogs and concomitant falls in PSA in patients with metastatic and locally advanced prostate cancer," said Dr. Langley. "The patches have been generally well tolerated."
Cardiovascular safety data have yet to be released, pending accrual of the 200-patient total for the study.
Nonetheless, on the basis of the results, the data monitoring committee recommended that investigators "focus their plans towards developing a larger, phase III trial," said Dr. Langley.
Oral estrogen won support as hormonal therapy for prostate cancer in the 1960s. However, the treatment fell out of favor because it was associated with increased cardiovascular morbidity, said Dr. Langley.
"The [cardiovascular] toxicity has been attributed to first-pass hepatic metabolism, which affects lipids and coagulation proteins," she said. "Since transcutaneous administration of estrogen avoids the enterohepatic circulation, it should not be associated with the same high levels of cardiovascular toxicity."
In a preliminary trial involving 20 patients with prostate cancer, estrogen patches lowered testosterone to castrate levels and caused no cardiovascular events, aside from one case of edema.
On the basis of those results, investigators organized a multicenter, randomized study that included 172 patients as of mid-February.
The trial involved patients with newly diagnosed T3/4 prostate cancer or with cancer in PSA relapse following definitive surgery or radiation therapy. Castrate-level testosterone was defined as 50 ng/dL.
The patients were randomized 1:2 to an LHRH analog or to transdermal patches that released 100 µg of estradiol per hour. After a planned review of data, investigators increased the patch dosage.
As a result, the first 33 patients randomized to transdermal patches received three patches, which were changed twice weekly. The remaining patients assigned to the estrogen group received four patches that were changed twice weekly.
Estradiol, testosterone, and PSA levels were measured at four weeks and three months and then every six months. In addition, investigators measured PSA levels at nine, 15, and 21 months.
At week four, 20 of 33 patients (60.6%) in the LHRH analog group had castrate levels of testosterone, as did 20 of 30 (66.6%) who received three estradiol patches, and 30 of 33 (90.9%)who received four patches.
Four LHRH analog patients had testosterone levels between 50 and 100 ng/dL, compared with five in the three-patch group and three in the four-patch group.
By week 12, 26 of 28 evaluable patients (92.8%) assigned to the LHRH analog had castrate levels of testosterone, and none had levels between 50 and 100 ng/dL.
Among patients treated with three estradiol patches, 21 of 29 (72.4%) had castrate levels of testosterone and six had levels of 50 to 100 ng/dL.
In the four-patch group, 27 of 31 patients (87%) had castrate testosterone levels and the other four had levels of 50 to 100 ng/dL.
At six months, the median testosterone levels were 14.3 ng/dL in the LHRH analog group, 28.6 ng/dL in the three-patch group, and 22.9 ng/dL in the four-patch group.
Median PSA values were 0.9 ng/mL, 3.2 ng/mL, and 1.3 ng/mL, respectively.
Dr. Langley and her coinvestigators reported no disclosures.
By Charles Bankhead, Staff Writer, MedPage Today
Published: March 03, 2009
Primary source: ASCO: Genitourinary Cancers Symposium
Source reference:
Langley RE, et al "PATCH, a randomized phase II trial of estrogen patches versus LHRH as first-line hormonal therapy for prostate cancer: planned interim analysis results" ASCO: GU 2009; Abstract 173.
Find this article at:
http://www.medpagetoday.com/MeetingCoverage/ASCOGU/13105?utm_source=WC&utm_medium=email&utm_campaign=Meeting_Roundup_ASCO%2520GU
Copyright MedPage Today, LLC. All Rights Reserved.
We hope you visit http://www.medpagetoday.com every day for the latest in medical news
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