Treatment of patients with metastatic urothelial cancer "unfit" for Cisplatin-based chemotherapy

PURPOSE

Cisplatin-based combination chemotherapy is considered standard first-line treatment for patients with metastatic urothelial carcinoma. However, a large proportion of patients with metastatic urothelial carcinoma are considered "unfit" for cisplatin. The purpose of this review is to define unfit patients and to identify treatment options for this subgroup of patients.

PATIENTS AND METHODS

In this review, the criteria used to define unfit patients are explored and the results of prospective clinical trials evaluating chemotherapeutic regimens in unfit patients are summarized.

RESULTS

Several phase II trials and a single, large phase III trial have explored chemotherapeutic regimens for the treatment of unfit patients with metastatic urothelial carcinoma. Heterogeneous eligibility criteria have been used to define unfit patients in these studies. A uniform definition of unfit is proposed on the basis of the results of a survey of genitourinary medical oncologists. According to this definition, unfit patients would meet at least one of the following criteria: Eastern Cooperative Oncology Group performance status of 2, creatinine clearance less than 60 mL/min, grade ≥ 2 hearing loss, grade ≥ 2 neuropathy, and/or New York Heart Association Class III heart failure.

CONCLUSION

Additional studies to optimize treatment for this important subset of patients are needed. A uniform definition of unfit patients will lead to more uniform clinical trials, enhanced ability to interpret the results of these trials, and a greater likelihood of developing a viable strategy for regulatory approval.

Phase II Trial of Cisplatin, Gemcitabine, and Bevacizumab As First-Line Therapy for Metastatic Urothelial Carcinoma: Hoosier Oncology Group GU 04-75

Purpose

Novel approaches are needed for patients with metastatic urothelial cancer (UC). This trial assessed the efficacy and toxicity of bevacizumab in combination with cisplatin and gemcitabine (CGB) as first-line treatment for patients with metastatic UC.

Patients and Methods

Chemotherapy-naive patients with metastatic or unresectable UC received cisplatin 70 mg/m2on day 1, gemcitabine 1,000 to 1,250 mg/m2on days 1 and 8, and bevacizumab 15 mg/kg on day 1, every 21 days.

Results

Forty-three patients with performance status of 0 (n = 26) or 1 (n = 17) and median age of 66 years were evaluable for toxicity and response. Grade 3 to 4 hematologic toxicity included neutropenia (35%), thrombocytopenia (12%), anemia (12%), and neutropenic fever (2%). Grade 3 to 5 nonhematologic toxicity included deep vein thrombosis/pulmonary embolism (21%), hemorrhage (7%), cardiac (7%), hypertension (5%), and proteinuria (2%). Three treatment-related deaths (CNS hemorrhage, sudden cardiac death, and aortic dissection) were observed. Best response by Response Evaluation Criteria in Solid Tumors was complete response in eight patients (19%) and partial response in 23 patients (53%), for an overall response rate of 72%. Stable disease lasting ≥ 12 weeks occurred in four patients (9%), and progressive disease occurred in six patients (14%). With a median follow-up of 27.2 months (range, 3.5 to 40.9 months), median progression-free survival (PFS) was 8.2 months (95% CI, 6.8 to 10.3 months) with a median overall survival (OS) time of 19.1 months (95% CI, 12.4 to 22.7 months). The study-defined goal of 50% improvement in PFS was not met.

Conclusion

CGB demonstrates promising OS and antiangiogenic treatment-related toxicities in the phase II setting of metastatic UC. The full risk/benefit profile of CGB in patients with metastatic UC will be determined by an ongoing phase III intergroup trial.

A phase II study of pemetrexed as second-line chemotherapy for the treatment of metastatic castrate-resistant prostate cancer (CRPC); Hoosier Oncology Group GU03-67

BACKGROUND

No standard therapy exists for post-docetaxel castrate-resistant prostate cancer (CRPC) patients. This trial aimed to determine the safety and efficacy of pemetrexed in post-docetaxel CRPC patients.

MATERIALS AND METHODS

CRPC patients with progression after docetaxel (Taxotere) therapy received pemetrexed (500 mg/m2) i.v. every 3 weeks. The primary end point was prostate-specific antigen (PSA) response. A pharmacogenetic analysis of the reduced folate carrier-1 gene (RFC1) G80A polymorphism was also carried out.

RESULTS

Forty-nine patients were enrolled: median age 68 years, median baseline PSA 72 ng/ml, and median Karnofsky performance status of 90. Grade 3 or 4 toxicity occurred in 20 (43%) and four patients (8%), respectively. Confirmed >50% PSA decline occurred in four patients (8%), stable PSA lasting at least 12 weeks in 10 patients (20%). A significant relationship was observed between time from prior docetaxel therapy and overall survival. Pharmacogenetic analyses of RFC1 G80A genotype frequencies showed no relationship between genotypes and clinical efficacy.

CONCLUSIONS

Pemetrexed treatment of CRPC patients after docetaxel therapy was associated with only modest clinical activity. Further investigation of pemetrexed as a single agent in a nonenriched CRPC population is unlikely to add significant clinical benefit over that seen with traditional second-line chemotherapy agents such as mitoxantrone.

Constitutional polymorphisms of prostate cancer: prognostic and diagnostic implications

Prostate cancer is the most common cancer diagnosis in men. While often perceived as a slow, indolent malignancy, prostate cancer trails only lung cancer among cancer-related mortality in men. Current diagnosis and treatment algorithms are plagued by overdiagnosis of non-lethal indolent prostate cancer with no proven means to predict, detect, and prevent aggressive lethal prostate cancer in men most at risk. These challenges are particularly concerning for African-American men who demonstrate increased rates of prostate cancer incidence and mortality when compared to other ethnic groups. With the completion of the human genome project, technology and techniques now exist to differentiate cancer from normal tissues based on the expression patterns of thousands of genes assessed simultaneously on a single microarray gene 'chip'. This platform has greatly improved our understanding of genes that regulate tumor behavior once cancer is established. Microarrays can also be utilized in patients without cancer to determine which patients are at high risk for tumor development and in need of rational prevention strategies. Constitutional single nucleotide polymorphisms (SNPs) are one source of genetic variation and may serve as a means to identify these high-risk individuals. SNPs are single nucleotide base pair changes within a gene which occur in one percent or more of the population. SNPs can contribute to a disease state by altering the function of a protein encoded by a gene without affecting gene expression. This review will examine the current understanding of constitutional SNPs associated with prostate cancer carcinogenesis, highlight two current diagnostic array platforms and discuss implications for future prevention and screening programs.

Hoosier Oncology Group randomized phase II study of docetaxel, vinorelbine, and estramustine in combination in hormone-refractory prostate cancer with pharmacogenetic survival analysis

PURPOSE

To determine the safety and efficacy of two docetaxel doublets in hormone-refractory prostate cancer (HRPC) patients and to examine the prognostic role of polymorphisms in host genes important to docetaxel metabolism and transport.

EXPERIMENTAL DESIGN

Sixty-four chemotherapy-naive patients with HRPC were randomized to docetaxel and vinorelbine (D, 20 mg/m2 i.v. days 1 and 8; V, 25 mg/m2 i.v. days 1 and 8) or docetaxel and estramustine phosphate (D, 60-70 mg/m2 i.v. day 1; E, 280 mg oral thrice daily days 1-5) administered q21d. Primary end point was clinically significant toxicity. A pharmacogenetic analysis of host genes was done in patients who received at least one cycle of docetaxel therapy.

RESULTS

Grade 3/4 toxicity occurred in 15.6% of DV patients and in 28.6% DE patients. Neither arm exceeded the threshold of clinically significant toxicity. In the DV arm, objective response rate was 33%, prostate-specific antigen response rate was 20%, and median survival was 16.2 months. In the DE arm, objective response rate was 67%, prostate-specific antigen response rate was 43%, and median survival was 19.7 months. Pharmacogenetic analyses showed a significant association between survival beyond 15 months and the ABCG2 421 C > A (Q141K) polymorphism compared with the wild-type (C/C) genotype (66% versus 27%; P = 0.05).

CONCLUSIONS

DV and DE doublets are active with a tolerable toxicity profile in patients with HRPC; however, efficacy does not seem superior to standard single-agent docetaxel. The ABCG2 421 C > A (Q141K) polymorphism may be an important predictor of response and survival in HRPC patients treated with docetaxel-based chemotherapy.

Germ cell tumors: An update of recent data and review of active protocols in stage I and metastatic disease

Germ cell tumors are highly curable malignancies even when metastatic. Investigations currently focus on curtailing toxicity in low-risk patients and improving cure rates in poor-risk individuals. Reduced dose radiation schedules and short-course chemotherapy regimens have been evaluated in stage I disease. In metastatic disease, several new nonplatinum agents offer promise for patients with poor risk or relapsed disease. In addition, high-dose chemotherapy regimens with autologous stem cell transplant provide potential for further improvements in survival. This review will highlight recent developments and currently active clinical trials pertinent to the treatment of patients with germ cell tumors.

Does Linezolid Cause Lactic Acidosis by Inhibiting Mitochondrial Protein Synthesis?

Linezolid, an oxazolidinone antibiotic, inhibits bacterial protein synthesis by binding to 23S ribosomal RNA (rRNA). We studied 3 patients who experienced lactic acidosis while receiving linezolid therapy. The toxicity may have been caused by linezolid binding to mitochondrial 16S rRNA. Genetic polymorphisms may have contributed to the toxicity in 2 patients.

Combined Chemoradiotherapy in Small Cell Lung Cancer

Combined chemoradiotherapy is the established standard of care for limited stage small cell lung cancer; it provides cure in 15% to 25% of patients. Early concurrent therapy imparts a 5% long-term survival benefit compared with sequential therapy. Hyperfractionated delivery of radiotherapy may provide a small incremental benefit when compared with standard fractionation. Radiotherapy dose escalation and reduced radiotherapy volumes are feasible; however, survival benefit has not been confirmed. Cisplatin and etoposide remain the preferred chemotherapy agents. New chemotherapeutic agents and novel treatment approaches are under intense investigation.