Phase II trial of pyrazoloacridine in patients with cisplatin-refractory germ cell tumors

Progression-free and overall survival in patients with relapsed/refractory germ cell tumors treated with single-agent chemotherapy: endpoints for clinical trial design

BACKGROUND

Refractory germ cell tumor (GCT) patients have a poor prognosis and limited treatment options. The identification of novel active agents may be impaired by use of response as the primary endpoint in phase 2 trials. Improved endpoints could enhance the development of new effective agents.

METHODS

The characteristics and outcome of refractory GCT patients enrolled in 7 single-agent phase 2 trials conducted at Memorial Sloan-Kettering Cancer Center from 1990 to 2008 were reviewed. The study agents were suramin, all-transretinoic acid, topotecan, pyrazoloacridine, temozolomide, ixabepilone, and sunitinib. The major endpoints evaluated were response, progression-free survival (PFS), and overall survival (OS).

RESULTS

Ninety patients (87 male, 3 female) were treated. The primary tumor site was testis in 65 patients, mediastinum in 17 patients, retroperitoneum in 4 patients, and other in 4 patients. Eighty-six patients had nonseminoma, and 4 patients had pure seminoma. Best responses were 1 (1%) partial response (ixabepilone), 15 (17%) stable disease, and 74 (82%) progressive disease. Median PFS and OS were 1.0 month (95% confidence interval [CI], 0.8-1.3) and 4.7 months (95% CI, 3.5-6.4), respectively. Eighty-six of the 90 patients have died. The 12- and 16-week PFS rates were 9% (95% CI, 3-15%) and 6% (95% CI, 1%-11%), respectively.

CONCLUSIONS

Patients with refractory GCT progressed rapidly to these single agents. PFS and OS may be useful endpoints for designing phase 2 trials testing novel agents in this population. Twelve-week PFS (with comparison to the 9% benchmark rate reported herein) is the recommended endpoint for phase 2 trial design and median OS (using 4.7 months as the predicted median for the control arm) is suggested for phase 3 trials.

Phase II trial of pyrazoloacridine (NSC#366140) in patients with metastatic breast cancer

PURPOSE

Pyrazoloacridine (PZA) is an investigational nucleic acid binding agent that inhibits the activity of topoisomerases 1 and 2. We conducted a phase II clinical study to determine the efficacy and toxicities of PZA in patients with metastatic breast cancer (MBC).

EXPERIMENTAL DESIGN

In this phase II multicenter study, patients who were treated with no more than one prior chemotherapy for MBC were treated with 750 mg/m² of PZA given as a 3-hour intravenous infusion every 3 weeks. Treatment cycles were continued until disease progression or unacceptable toxicities. The study was designed to distinguish between a response rate of < 15% vs > 30% (alpha = 0.10, beta = 0.10) using Simons optimal 2-stage design. At least 2 responses were required in the first 12 patients in the 1st stage and 6 of 35 in the 2nd stage to recommend the agent for further study.

RESULTS

Two patients in the first stage had a response allowing accrual to second stage. A total of 15 patients (out of 35 planned) were treated on the study prior to premature closure. Three patients had a partial response (20%) lasting 4.5-6 months. Two patients had stable disease for 3 and 5 months. The dose limiting toxicity was granulocytopenia with ten patients requiring dose reduction or dose delay for grade 4 neutropenia. Other grade 3 and 4 toxicities include vomiting (n = 2), nausea (n = 2), neurotoxicity (n = 1), fatigue (n = 1), anemia (n = 1), dyspnea 9n = 1) and renal (n = 1).

CONCLUSIONS

Pyrazoloacridine demonstrated modest activity in patients with metastatic breast cancer.

Recent advances in the treatment of testicular cancer

Testicular cancer is remarkable because it is curable by combination cytotoxic chemotherapy even when widely disseminated. Treatment is defined by widely accepted staging and prognostic factors. Three cycles of bleomycin, etoposide and cisplatin has been defined as the current optimum treatment in good prognosis metastatic disease, curing 90-95% of patients. Outcomes are less impressive for patients in intermediate and poor prognostic categories. A number of different approaches, including introduction of new agents and dose intensification, are being investigated to improve outcomes in these patients. Data developed over the last few years have identified increased risks of second malignancy and cardiovascular disease in long-term survivors. This has led to re-evaluation of strategies to manage Stage I patients. In particular, the use of radiotherapy in Stage I seminoma and the need for adjuvant therapy in Stage I nonseminoma are being re-examined. It is anticipated that advances in imaging and prognostic factors will facilitate this process.

The management of poor-prognosis, non-seminomatous germ-cell tumours

Despite a high cure rate in men with testicular cancer, some men in the poor-prognosis group have a less favourable outcome. Poor-prognosis non-seminomatous germ-cell tumours (NSGCT) are defined as those with high tumour markers, non-pulmonary visceral metastases or a mediastinal primary site at presentation. When treated with standard chemotherapy regimens, such as bleomycin, etoposide and cisplatin (BEP), cure rates of less than 50% have been achieved in an international pooled analysis. Some strategies aimed at improving results include the use of multi-agent regimens (e.g. POMB/ACE), intensive-induction chemotherapy (e.g. CBOP/BEP), new chemotherapy drugs, such as ifosfamide, gemcitabine, oxaliplatin, paclitaxel, high-dose chemotherapy, including autotransplantation. To date, no schedule has been proven to be better than standard BEP in randomised trials. We will review the published data relating to first-line and salvage treatment of poor-prognosis NSGCT. To advance the management of this disease, physicians treating poor-prognosis disease are urged to support multi-centre trials, such as the recently launched MRC TE23 study comparing BEP and CBOP/BEP.

Synergistic Cytotoxicity of Pyrazoloacridine with Doxorubicin, Etoposide, and Topotecan in Drug-Resistant Tumor Cells

Pyrazoloacridine (NSC 366140, PD115934, PZA) is a new class of acridine anticancer agents under investigation in Phase II clinical trials in patients with advanced cancers. Although poor responses in patients to the treatment with PZA alone have been observed, this class of agents remains of interest because of its distinct mechanism of action from other topoisomerase poisons. Therefore, the combination of PZA with conventional anticancer agents presents an attractive approach to treat drug-resistant human tumors. In the present study, the cytotoxic effects of PZA combined with doxorubicin, topotecan, and etoposide were determined using paired parental and doxorubicin-resistant human colon carcinoma (SW-620 and SW620/AD-300) and breast cancer cell lines (MCF-7 and MCF-7/TH). Cytotoxicity was measured by soft agar clonogenic assays. Dose effect and combination effects were analyzed by the method of Chou and Talalay. The combination of PZA with doxorubicin, topotecan, and etoposide in fixed ratios demonstrated synergistic cytotoxicity on both SW-620 and SW620/AD-300 cell lines. The combination of PZA with doxorubicin also exhibited synergistic cytotoxicity against both MCF-7 and MCF-7/TH cell lines. The mechanism of synergism appeared independent of topoisomerase I and II inhibition, and interference with protein-DNA complexes. Strategies to define optimal drug combinations are proving to be of significant value when considering potential clinical applications of new and established agents.

Phase II trial of pyrazoloacridine in patients with persistent or recurrent endometrial carcinoma: a Gynecologic Oncology Group Study

OBJECTIVES

The aims of this study were to determine the response rate of pyrazoloacridine (PZA) in patients with recurrent or persistent endometrial carcinoma and to describe the nature and degree of toxicity in this population.

METHODS

PZA was initially administered at a dose of 750 mg/m(2) intravenously over 3 h every 3 weeks but, due to toxicity, was subsequently reduced to 560 mg/m(2) at the same schedule.

RESULTS

Among 23 evaluable patients, 11 of whom had had prior chemotherapy, there was 1 (4.3%) partial response and no complete responses. Forty-eight percent of patients had grade 4 neutropenia. There was 1 treatment-related death, in a patient who had prior chemotherapy and radiotherapy.

CONCLUSION

This dose and schedule of PZA has insignificant activity in this population. The optimal PZA dose appears to vary between different populations and may be related to prior therapy.

Role of postchemotherapy adjunctive surgery in the management of patients with nonseminoma arising from the mediastinum

PURPOSE

To evaluate the role of postchemotherapy surgery in patients with nonseminomatous germ cell tumors arising from the anterior mediastinum.

PATIENTS AND METHODS

Thirty-two patients with nonseminoma arising from a mediastinal primary site were treated on a clinical trial at our center, and they underwent postchemotherapy surgery. The results of postchemotherapy surgical resection, frequency of viable tumor found during postchemotherapy surgery, and prognostic factors for survival were assessed.

RESULTS

Complete resection of all gross residual disease was achieved in 27 patients (84%). Histologic analysis of resected residua postchemotherapy revealed viable tumor in 66%, teratoma in 22%, and necrosis in 12% of the specimens. Viable tumor included embryonal carcinoma, choriocarcinoma, yolk sac carcinoma, seminoma, and teratoma with malignant transformation to nongerm cell histology (eg, sarcoma). Clinical characteristics associated with a shorter survival after surgery included the presence of viable tumor in a resected specimen (P =.003) and more than one site resected during surgery (P =.06). There were no statistically significant differences in survival for patients who underwent surgical resection with normal markers compared with patients with elevated serum tumor markers (P =.33). A trend toward shorter survival was found in patients with increasing tumor markers before surgery compared with patients with normal and declining serum tumor markers (P =.09).

CONCLUSION

Surgical resection of residual mass after chemotherapy plays an integral role in the management of patients with primary mediastinal nonseminoma. Teratoma and viable tumor were found in the majority of resected residua after chemotherapy. Because patients who undergo conventional salvage chemotherapy programs rarely achieve long-term disease-free status, selected patients with elevated markers after chemotherapy are considered candidates for surgical resection.