Leucovorin and high-dose fluorouracil in metastatic prostate cancer. A phase II trial of the piedmont Oncology Association

Hormone Refractory Prostate Cancer (Hrpc): Present and Future Approaches of Therapy

The mainstay of therapy for patients with advanced prostate cancer still remains androgen deprivation, although response to this is invariably temporary. Most of the patients develop hormone-refractory disease resulting in progressive clinical deterioration and, ultimately, death. Until recently there has been no standard chemotherapeutic approach for hormone refractory prostate cancer (HRPC), the major benefits of chemotherapy being only palliative. The studies combining mitoxantrone plus a corticosteroid demonstrated that chemotherapy could be given to men with symptomatic HRPC with minimal toxicity and a significant palliation could be provided. Recently, results from 2 phase III randomized clinical trials demonstrating that a combination of docetaxel plus prednisone can improve survival in men with HRPC have propelled docetaxel-based therapy into the forefront of treatment options for these patients as the new standard of care. There is a promising activity of new drug combinations such as taxanes plus vinca alkaloids; bisphosphonates are assuming a prominent role in prostate therapy through their ability to prevent skeletal morbidity. Combinations of classic chemotherapeutic agents and biological drugs began to be tested in phase II-III trials and the first results appear interesting. This article focuses on combinations recently evaluated or under clinical development for the treatment of HRPC.

Is There a Standard Chemotherapeutic Regimen for Hormone-Refractory Prostate Cancer? Present and Future Approaches in the Management of the Disease

Prostate cancer that no longer responds to hormonal manipulation can be defined as hormone-refractory prostate cancer. Until recently, there has been no standard chemotherapeutic approach for hormone-refractory prostate cancer. The major benefits of chemotherapy in the treatment of the disease are palliative in nature, in terms of reduction of pain and use of analgesics and improvement of performance status, as followed in the most recent trials. Phase III studies are necessary to better evaluate the efficacy of the different regimens, because several old studies suffer for methodological deficits. There is a promising activity of new drug combinations, such as vinca alkaloids and taxanes. Phase I and II trial are testing combinations of classic chemotherapeutic agents and biologic drugs, and the first results appear interesting. In this article, recent advances in the treatment of hormone-refractory prostate cancer using chemotherapeutic regimens are critically reviewed.

Phase II study of oral capecitabine in patients with hormone-refractory prostate cancer

BACKGROUND

Currently available treatment for hormone refractory prostate cancer is limited in efficacy and associated with significant toxicity. This phase II study was performed to assess the efficacy of the oral fluoropyrimidine capecitabine in advanced prostate cancer.

PATIENTS AND METHODS

Patients who had a rising prostate-specific antigen (PSA) despite androgen withdrawal, but who remained free from cancer-related symptoms. In total, 14 patients received oral capecitabine 1250 mg/m2 twice daily for two weeks of a three-week cycle. Tumour response was assessed using serum PSA measurement at 3-weekly intervals and, where present, imaging of soft tissue metastases.

RESULTS

One of 14 patients experienced a partial response as assessed by both PSA and imaging of liver metastases. In seven other patients (50%), treatment decreased the rate of PSA rise. The duration of PSA stabilisation was generally short, but in 5/14 patients (36%) was sustained beyond 18 weeks, and in one patient to 24 weeks. Toxicity was significant but manageable, the most common adverse events being nausea, mucositis and hand-foot syndrome, each occurring in 50% of patients. Other common side effects were diarrhoea and lymphopenia. All toxicities were grade 1 or 2, except for grade 3 hand-foot syndrome occurring in one patient, and no dose reduction was required because of toxicity.

CONCLUSION

Capecitabine has limited activity as a single agent in prostate cancer, but appears to modulate tumour biology. Considering the added convenience of oral administration, these results support further evaluation of combinations containing capecitabine in hormone-refractory prostate cancer.

Capecitabine in hormone-resistant metastatic prostatic carcinoma - a phase II trial

The objective of the trial is to evaluate the efficacy of capecitabine in patients with metastatic hormone-resistant prostate carcinoma (HRPC), in terms of prostate-specific antigen (PSA) response and clinical benefit (decrease of pain or analgesic score) and its safety profile. In all, 25 patients with HRPC were enrolled on a phase II trial of capecitabine (Xeloda) at a dose of 1250 mg m(-2) orally twice daily on days 1-14 every 21 days. The inclusion criteria were PSA serum levels >3 x upper limit of normal, a WHO performance status 0-2, age <85 years and adequate bone marrow, liver and renal function. In patients with grade 2 or higher haematological toxicity on day 1 of the treatment cycle, therapy was first delayed, and then continued at a lower dose. Trial end points were PSA response and clinical benefit defined by quality of life (QL) data and analgesic consumption. The median age of patients was 70 years (range 54-85 years). A median of three cycles of capecitabine was administered (range 1-8). PSA response was observed in three patients (12%, 95% CI 3-31%), with times to tumour progression of 18, 21 and 35 weeks, respectively. In these patients, the response durations were 12, 17 and 32 weeks, respectively. Minor PSA regression was also seen in two further patients. The median time to tumour progression of all patients was 12 weeks (95% CI 9-15 weeks). Haematological toxicity was minor, with leukopenia grade 3 observed in one patient. There were three deaths during trial treatment, respectively, due to sepsis following mucositis and leukopenia, presumed sepsis with mucositis induced by chemotherapy and concomitant radiotherapy and cerebral dysfunction progressing to coma. Hand-foot syndrome grades 2 and 3 were observed in four patients each. Clinical benefit was observed in five patients (20%, CI 7-41%). Based on toxicity data, we recommend a lower starting dose of 1000 mg x m(-2) orally twice daily. While capecitabine has some activity in HRPC, as suggested by observed PSA responses, we conclude that it is not worthwhile to investigate capecitabine monotherapy in a phase III trial. Combinations of capecitabine with other agents, such as vinorelbine or docetaxel, may prove to be more effective.

Phase II study of repeated single 24-hour infusion of low-dose 5-fluorouracil for palliation in symptomatic hormone-refractory prostate cancer

BACKGROUND

To assess the efficacy and toxicity of repeated single 24-hour infusion of low-dose 5-fluorouracil for symptomatic hormone-refractory prostate cancer using relevant endpoints of palliation and biological response.

PATIENTS AND METHODS

25 patients with histologically confirmed prostatic adenocarcinoma and symptomatic progressive disease despite one or several hormonal treatments and chemotherapy were included in the study. Treatment consisted of a single 24-hour infusion of 500 mg/m(2) 5-fluorouracil (5-FU) to be repeated on day 21. This regimen was continued until either progression or serious toxicity occurred. Response was assessed by serial measurements of serum prostate-specific antigen (PSA) as well as by health-related quality-of-life instruments (EORTC QLQ-C30 and McGill-Melzack Present Pain Intensity Scale) every 3 weeks. In 10 patients with bidimensionally measurable metastases, objective responses were assessed every 3 months.

RESULTS

A mean number of four courses of repeated single 24-hour infusion of 5-FU was administered (range 2-6). Toxicity was absent or mild, and no patient had to be withdrawn from therapy. All patients required analgesics prior to treatment and only 3 patients experienced a significant reduction in pain for 9 weeks, the remaining patients experienced no deterioration for a mean duration of 12 weeks (6-18 weeks). Five patients (20%) demonstrated a biological response of a 50% or greater decrease in PSA from baseline, including 2 (12%) with a 75% or greater decline for 10 weeks (range 6-16 weeks). One partial remission was observed among 10 patients with measurable lesions lasting 12 weeks; 4 patients had stable disease with a mean duration of 12 weeks. Mean survival time from the onset of treatment with 5-FU was 7 months (2-12 months).

CONCLUSIONS

Though less toxic than other 5-FU regimens, repeated single low-dose 24-hour infusion is of no significant benefit in patients with symptomatic hormone-refractory prostate cancer.

Current strategies in the management of hormone refractory prostate cancer

Prostate cancer is the most common cancer diagnosed in American males, and is the second leading cause of cancer-related deaths. Most patients who develop metastatic disease will initially respond to androgen deprivation, but response is invariably temporary. Most patients will develop androgen-independent ("hormone-refractory") disease that results in progressive clinical deterioration and ultimately death. This progression to androgen independence is accompanied by increasingly evident DNA instability and alterations in genes and gene expression, including mutations in p53, over-expression of Bcl2, and mutations in the androgen receptor gene, among others. Treatment options for hormone refractory disease include intensive supportive care, radiotherapy, bisphosphonates, second-line hormonal manipulations, cytotoxic chemotherapy and investigational agents. A post-treatment reduction in the level of prostate specific antigen (PSA) by 50% has been shown to correlate with survival and has been accepted by consensus as a valid endpoint in clinical trials. Chemotherapeutic agents such as mitoxantrone, estramustine, and the taxanes have yielded improved response rates and palliative benefit, but not improved survival. Therefore, current efforts must be focused on enrolling patients onto clinical trials of investigational agents with novel mechanisms of action, and on using survival, time to progression, and quality of life as end points in routine clinical practice.