The Oncologist, Vol. 9, No. 6, 687-695, November 2004; doi:10.1634/theoncologist.9-6-687 © 2004 AlphaMed Press
Safety and Pain Palliation of Zoledronic Acid in Patients with Breast Cancer, Prostate Cancer, or Multiple Myeloma Who Previously Received Bisphosphonate Therapya Cancer Research Network, Plantation, Florida, USA; b Gilroy Private Practice, Gilroy, California, USA; c Cancer Specialist of South Texas, Corpus Christi, Texas, USA; d Central Georgia Hematology Oncology Associates, Macon, Georgia, USA; e Peachtree Hematology/Oncology Associates, Atlanta, Georgia, USA; f Queens Medical Associates, Fresh Meadows, New York, USA; g Hematology Oncology Associates of Albuquerque, Albuquerque, New Mexico, USA; h Northwestern Carolina Hematology/Oncology, Hickory, North Carolina, USA; i Novartis Oncology, Florham Park, New Jersey, USA Correspondence: Charles L. Vogel, M.D., Cancer Research Network, 350 NW 84th Avenue, Suite 305, Plantation, Florida 33324, USA. Telephone: 954-473-6776; Fax: 954-473-4552; e-mail: drcvogel{at}aol.com
An open-label study conducted in community centers assessed the safety of zoledronic acid 4 mg intravenously over 15 minutes every 34 weeks as treatment of bone metastases in patients with multiple myeloma, breast cancer, or prostate cancer with and without previous bisphosphonate exposure. Adverse events (AEs), pain, and quality-of-life (QOL) scores were recorded, and serum creatinine (SCr) levels were measured before each infusion. Of 638 patients, 415 patients (65%) had received prior bisphosphonate therapy. Fatigue, nausea, and arthralgia were the most frequent AEs. Nausea was more common in bisphosphonate-naïve patients. SCr levels increased notably in 6.6% of patients: 7.7% of patients who received prior bisphosphonate therapy and 4.5% of bisphosphonate-naïve patients. Treatment was delayed because of SCr-level increases in 1.4% of patients with prior bisphosphonate exposure and 0.4% of bisphosphonate-naïve patients. SCr-level increases and treatment delays did not correlate with duration of prior bisphosphonate therapy. There was a trend towards more treatment discontinuations in patients with prior bisphosphonate exposure compared with bisphosphonate-naïve patients. Pain scores decreased from baseline; total QOL scores remained constant. The results of this study suggest that, with proper SCr-level monitoring, cancer patients with bone metastases who have previously received intravenous bisphosphonate treatment can be safely converted to zoledronic acid therapy. Key Words. Zoledronic acid • Pamidronate • Bisphosphonate • Bone metastases
In 65%75% of patients with advanced breast or prostate cancer and 70%95% of patients with multiple myeloma, bone metastases are a common cause of morbidity [1, 2]. The activation of osteoclasts by cancer cells that have migrated to the bone microenvironment causes increased resorption of mineralized bone, resulting in cortical bone destruction [1]. As potent inhibitors of osteoclast activity, bisphosphonates are effective agents in the treatment of metastatic bone lesions, decreasing both the symptoms (e.g., bone pain) and complications (e.g., pathologic fracture, spinal cord compression, hypercalcemia) associated with metastatic bone disease [1, 2]. Zoledronic acid (Zometa®; Novartis Pharmaceuticals Corporation; East Hanover, NJ), a new highly potent, heterocyclic, nitrogen-containing bisphosphonate, has a more convenient administration schedule and is at least as or more effective than pamidronate (Aredia®, Novartis), the previous i.v. bisphosphonate of choice for treatment of bone metastases in patients with breast cancer or multiple myeloma [1, 3, 4]. Zoledronic acid is the only bisphosphonate proven effective in the treatment of bone metastases in patients with advanced prostate cancer and other solid tumors [3, 5, 6]. In clinical trials of zoledronic acid, the most common bisphosphonate-related adverse events (AEs) were bone pain, nausea, and fatigue [7]. The incidence of renal dysfunction was similar in patients receiving zoledronic acid 4 mg over 15 minutes and patients receiving pamidronate 90 mg over 2 hours; the incidence was higher in patients receiving zoledronic acid 4 mg or 8 mg over 5 minutes [1, 3, 7]. Therefore, adhering to current zoledronic acid administration guidelines (i.e., administration of 4 mg by i.v. infusion over no less than 15 minutes) is important to minimize the development of renal dysfunction [7]. Before Food and Drug Administration (FDA) approval of zoledronic acid, many cancer patients with bone metastases received pamidronate. Many of these patients are now treated with zoledronic acid. Approximately one-third of patients treated with i.v. bisphosphonates still receive pamidronate, although many may be candidates for conversion to zoledronic acid. Data regarding the safety of zoledronic acid in patients with a history of significant exposure to bisphosphonate therapy are limited; phase III trials evaluating zoledronic acid in cancer patients with bone metastases excluded this patient population [1, 35]. Therefore, an evaluation of the safety of zoledronic acid in patients who received prior i.v. bisphosphonate therapy is warranted and will support the clinical rationale for converting appropriate patients to zoledronic acid. This article reports the results of a community-based study of zoledronic acid (4 mg through a 15-minute infusion) in patients with breast cancer, prostate cancer, or multiple myeloma and bone metastases; most of these patients received prior bisphosphonate therapy. The objectives of the study were to assess: A) overall and renal safety; B) changes in pain scores from baseline; C) quality of life (QOL); and D) infusion duration. Results were analyzed according to tumor type and history of bisphosphonate therapy.
Patients Ambulatory adult patients ( 18 years of age) with at least one cancer-related bone lesion detected by conventional radiography or bone scan and either Durie-Salmon stage III multiple myeloma or biopsy-proven breast or prostate cancer were enrolled in the study. The study protocol required all patients to have an FDA-approved indication for treatment with zoledronic acid; therefore, patients with prostate cancer were included only if their disease had progressed after receiving one or more hormone therapy regimens. All patients had a baseline Eastern Cooperative Oncology Group performance status of 2.
Patients were excluded if they had abnormal renal function defined as either a serum creatinine (SCr) level that was at least 1.5 times above the upper limit of normal or a calculated creatinine clearance value of Planned enrollment was approximately 500 patients to allow sufficient statistical power for analyses of pain, QOL, and safety parameters. The study was approved by the institutional review boards of the participating institutions and conducted in compliance with international guidelines regulating patient safety. Informed consent was obtained from each patient before enrollment.
Study Design and Treatment Patients were instructed to take a calcium supplement (500 mg) and a multivitamin tablet containing vitamin D (400500 IU) once daily for the study duration. The study allowed concomitant treatment with all standard antineoplastic therapies, radiation therapy for skeletal and nonskeletal tumor sites, use of standard cytokines or colony-stimulating factors for prevention or treatment of chemotherapy-induced cytopenias and corticosteroids for prevention or treatment of chemotherapy-induced nausea and vomiting, treatment of spinal cord compression or other recognized cancer syndromes, and administration of other marketed therapies. Therapies that affect osteoclast activity, such as calcitonin, mithramycin, gallium nitrate, or a bisphosphonate other than the study drug, were not permitted.
Assessments Pain assessments were conducted at baseline, before each infusion, and at the final study visit using a 100-mm visual analog scale (VAS). QOL was assessed at baseline and before infusions at visits 2 and 6 using the Functional Assessment of Cancer Therapy-General (FACT-G) questionnaire [8]. At each study visit, study personnel recorded the duration of infusion.
Statistical Analysis
Patients All 638 patients enrolled in the study were assessable for safety. Of these patients, 613 (96.1%) were assessable for pain, QOL, and infusion time (ITT population). All study visits were completed by 472 patients (74%); 166 patients (26%) discontinued therapy prematurely. The most common reasons for therapy discontinuation were AEs (6.4%), death (6.3%), serious AEs (3%), withdrawal of consent (4.9%), abnormal laboratory values (3%), and lack of follow-up (2.5%). Discontinuation reasons and rates were similar among all cancer types.
Overall, 77.4% of patients received all six infusions, including 78% of patients with breast cancer, 75.3% of patients with prostate cancer, and 78.3% of patients with multiple myeloma. Table 1
A total of 415 patients (65%) had received prior bisphosphonate therapy: one hundred ninety-six of these patients (47.2%) had received more than 6 but less than 24 months of prior treatment, and 110 (26.5%) had received at least 24 months of prior treatment. Most patients (95.4%) with prior exposure to bisphosphonates had received pamidronate. Three patients (0.7%) had received zoledronic acid, 8 patients (1.9%) had received both pamidronate and zoledronic acid, 7 patients (1.7%) had received alendronate, and in 2 patients (0.3%) the specific prior bisphosphonate received was unknown.
Overall Safety
Fatigue was the most common AE in patients with prostate cancer and multiple myeloma; nausea was the most common AE in patients with breast cancer. Dyspnea and vomiting were more common in patients with breast cancer than in patients with multiple myeloma or prostate cancer. Nausea was more common in patients with no prior bisphosphonate exposure (20% versus 12%); however, the incidence of other acute-phase reactions, such as arthralgia and fever, did not differ based on prior bisphosphonate exposure nor did the overall incidence of other AEs (Table 2
Renal Safety
Of the seven patients (1.1%) that had a protocol-specified treatment delay because of a notable SCr level increase, six patients (1.4%) had received prior bisphosphonate therapy and one patient (0.4%) was bisphosphonate naïve, p = 0.25 (Table 3 Only one serious renal AE was suspected to be related to the study drug. A 74-year-old patient with prostate cancer developed grade 2 renal failure, concomitant congestive heart failure, and pneumonia 42 days after beginning the study and subsequently discontinued study medication because of poor medical condition. This patient had no history of bisphosphonate therapy.
Pain Scores
QOL Scores Total mean FACT-G scores remained constant from baseline to visits 2 and 6 for the ITT population (Fig. 2
Infusion Time The mean infusion duration for the 3,374 infusions administered during the study was 17 minutes (range, 575 minutes), with the mean infusion duration for each visit varying only slightly throughout the study. Infusions of 14 minutes occurred during only 3% of the infusions, demonstrating strict adherence to the protocol and prescribing information for zoledronic acid (i.e., administration of 4 mg by i.v. infusion over no less than 15 minutes) [7].
The results of this open-label study demonstrate the safety of zoledronic acid as treatment of bone metastases secondary to multiple myeloma, breast cancer, or prostate cancer in patients with or without prior bisphosphonate exposure. In this study, 65% of patients received prior bisphosphonate therapy, primarily with pamidronate. Because patients receiving previous bisphosphonate therapy were excluded from the phase III trials evaluating zoledronic acid as treatment for bone metastases, the results of this study demonstrating the safety of zoledronic acid in patients previously exposed to bisphosphonates are both timely and clinically relevant. Zoledronic acid was generally well tolerated in this study, with 77% of patients completing all six infusions. AEs reported were similar to AEs experienced by patients in other trials evaluating i.v. bisphosphonate therapy [1, 35, 7]. With the exception of a higher incidence of nausea in bisphosphonate-naïve patients, the incidence of AEs did not differ based on history of prior bisphosphonate treatment. The overall incidence of AEs in this trial was lower than the incidence noted in the integrated safety analysis presented in the zoledronic acid package insert [7]. Bone pain occurred in only 8.9%11.2% of patients [7]. Zoledronic acid displayed renal safety, with 6.6% of patients developing a notable increase in their SCr level, and only 1.1% of patients requiring a treatment delay due to an increased SCr level. Furthermore, only 3.1% of patients discontinued therapy because of a change in SCr level. These very low rates of treatment delay and discontinuation, in patients receiving anticancer therapy, indicate that the overall SCr-level increases in this study were minor and manageable.
Patients with multiple myeloma experienced a slightly higher incidence of notable SCr-level increases compared with patients with breast or prostate cancer. This finding is not surprising given the underlying, disease-related renal dysfunction in many patients with multiple myeloma. Despite the higher incidence of notable SCr-level increases in patients with multiple myeloma, these patients did not experience substantially higher rates of treatment delay or discontinuation compared with patients with breast or prostate cancer. More patients who received prior bisphosphonate therapy had treatment discontinued because of increased SCr level than patients with no prior bisphosphonate exposure (Table 3
The duration of prior bisphosphonate therapy did not significantly affect the incidence of notable SCr level increases or treatment delays due to SCr level increases. Rates of treatment discontinuation due to SCr-level changes increased proportionally according to duration of prior bisphosphonate therapy (Table 3
The rate of notable SCr-level increases in this study ( Both pamidronate and zoledronic acid have been shown to decrease the incidence and/or severity of bone pain in some patients with bone metastases, although a number of factors other than bisphosphonate therapy may have contributed to this decrease, such as a response to antitumor therapy or the use of pain medications and/or other supportive care therapies [1, 3, 5, 911]. In this study, pain scores in patients receiving zoledronic acid decreased from baseline at each assessment, suggesting that zoledronic acid may help manage pain resulting from osteoclastic bone destruction and does not increase the incidence or severity of bone pain in patients with bone metastases. Statistically significant, albeit modest, reductions in mean pain scores compared with baseline scores occurred more often in patients with multiple myeloma or breast cancer than patients with prostate cancer. Nonetheless, mean pain scores in patients with prostate cancer did not increase at any assessment. A more rigorous and comprehensive pain and opioid assessment may have provided greater insight into the role of zoledronic acid for the palliation of bone pain. Several trials assessing the safety and efficacy of bisphosphonate therapy in cancer patients with bone metastases have also included an assessment of QOL [3, 5, 911]. Because many factors other than bisphosphonate therapy influence QOL in these patients (i.e., AEs associated with anticancer therapy, underlying disease progression), the results of these trials have been inconsistent [3, 5, 911]. In some trials, QOL scores were similar in patients receiving bisphosphonates or placebo; in other trials, bisphosphonate-treated patients had less of a reduction in QOL scores compared with placebo-treated patients [3, 5, 911]. In this study, overall QOL remained stable. Patient-reported measures of physical and emotional well-being improved, whereas measures of functional and social well-being declined. The decline in functional and social well-being may have been related to the course of the underlying disease, concomitant administration of chemotherapy or radiation therapy, or other comorbid medical conditions or life situations. Although a variety of factors influence QOL measurements at any given time, our study results suggest that zoledronic acid therapy does not adversely affect overall QOL.
Zoledronic acid 4 mg administered as a 15-minute infusion every 34 weeks was well tolerated in patients with bone metastases from multiple myeloma, breast cancer, or prostate cancer, including patients who had significant prior exposure to bisphosphonates. With proper SCr-level monitoring, patients with bone metastases who have received prior bisphosphonate therapy can be safely converted to zoledronic acid. Although there was a trend towards more treatment discontinuations because of increased SCr level in patients with prior bisphosphonate exposure and with an increased duration of prior bisphosphonate therapy, the incidence of treatment discontinuations in these patients was still low. Overall, administration of zoledronic acid is safe in patients who have previously received a bisphosphonate.
The authors gratefully acknowledge the study investigators and the participation of their patients. In addition to the authors, principal investigators at centers enrolling six or more patients include the following: Drs. Farlborze Barhamand, Albert Begas, Birbal Bhaskar, Linda Bosserman, Marc Citron, Alan Cohen, Steven Come, Shaker Dakhil, S. Paul Dang, Margaret Deutsch, George Geils, Richard Greenberg, Alan Grosbach, Alan Grosset, Allan Grossman, Michael Guarino, David Haidak, Ronald Hart, Carolyn Hendricks, Jeremy Hon, Frank Howard, John Huffman, Sang Huh, Leonard Kalman, L. Wayne Keiser, Leslie Laufman, Robert Lemon, James Liebmann, Tim Lopez, Kirk Lund, Michael McCleod, Aminder Mehdi, Paul Michael, G. Lance Miller, David Minor, David Mintzer, Allen Nixon, Richard Nora, Phatama Padavanija, Taral Patel, David Rinaldi, Marc Saltzman, Donald Strickland, Edmund Tai, Steven Tucker, Ann Wierman, Patrick Williams, Charles Winkler, Jeffrey Wisch, and S. Donald Zaentz.
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