TJ ISSN Introduction SHORT COMMUNICATION

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1 TJ ISSN Tumori 2017; 103(1): e4-e8 DOI: /tj SHORT COMMUNICATION Efficacy and safety of vinorelbine-capecitabine oral metronomic combination in elderly metastatic breast cancer patients: VICTOR-1 study Marina E. Cazzaniga 1, Valter Torri 2, Francesca Riva 1, Luca Porcu 2, Federica Cicchiello 1, Serena Capici 1, Diego Cortinovis 1, Nunzio Digiacomo 1, Paolo Bidoli 1 1 Oncology Department, San Gerardo Hospital, Monza - Italy 2 Oncology Unit, Mario Negri Institute, Milan - Italy Abstract Purpose: Elderly patients with metastatic breast cancer are expected to derive similar benefits from chemotherapy as younger patients, but are more likely to experience therapy-related toxicity. Data from the VICTOR-1 study showed that metronomic therapy with vinorelbine and capecitabine was effective and well tolerated in patients with metastatic breast cancer. This analysis determined the efficacy and safety of the metronomic combination of oral vinorelbine and capecitabine in a subgroup of VICTOR-1 study patients aged 70 years. Methods: Eighteen of the 32 patients enrolled in VICTOR-1 were aged 70 years. Objective response and clinical benefit rates were calculated and toxicity was determined using the NCI-CTCAE criteria. Results: All patients had at least 1 comorbidity (4 had 2 comorbidities), and 77.7% were taking concomitant medication. Eight patients (44%) had received 1 chemotherapy regimens for metastatic disease and most (78%) had 2 metastatic sites. Grade 1-2 adverse events occurred in 45.8% of cycles, whereas the incidence of grade 3 and grade 4 events was very low (1.5% and 0.7%, respectively). Median time to progression was 10.5 months (range 1-40). The objective response rate was 33% and the clinical benefit rate was 67%. Conclusions: The all-oral metronomic combination of vinorelbine and capecitabine had an acceptable efficacy profile and appears to be better tolerated than standard treatment schedules in elderly metastatic breast cancer patients (age 70 years). Keywords: Breast cancer, Capecitabine, Elderly, Metronomic chemotherapy, Vinorelbine Introduction In elderly breast cancer patients there is a delicate balance between overtreatment and undertreatment of advanced disease, and preservation of quality of life (QoL) is a priority. Generally, elderly patients with metastatic breast cancer are expected to derive similar benefits from chemotherapy to younger patients in terms of response and delay of progression but, because the risk of toxicity is increased, QoL may be impaired during treatment (1). Although there is no gold-standard chemotherapy for elderly patients, it is reasonable to consider monotherapy as Accepted: June 17, 2016 Published online: August 24, 2016 Corresponding author: Marina E. Cazzaniga Oncology Department AO S Gerardo Via Pergolesi Monza, Italy marina.cazzaniga@hsgerardo.org the first choice because compliance in patients with multiple comorbidities and the ability to treat toxicities at home may both be limited. As a result, the risk of serious adverse events and inadequate dose intensity with polychemotherapy regimens outweighs the potential gain in efficacy. However, some clinical situations (e.g., liver metastases) may require polychemotherapy. Data on polychemotherapy in elderly patients are limited. In general, oral drugs are preferred because of less requirement for hospital visits and better patient acceptability. Metronomic chemotherapy is the frequent, regular administration of drug doses designed to maintain low, but active, concentrations of chemotherapeutic drugs over prolonged periods of time, without causing serious toxicities (2). Considering the promising results reported with other metronomic combinations, e.g., cyclophosphamide + methotrexate (3), elderly patients were included in the VICTOR-1 study of patients with advanced breast cancer (4) to provide efficacy and safety data that could be applied to clinical practice in cases where polychemotherapy is needed. In VICTOR-1, vinorelbine (VRL) 40 mg was given 3 times a week and capecitabine (CAPE) 500 mg was given 3 times daily (tid) after food. There was a very low incidence of grade

2 Cazzaniga et al e5 Fig. 1 - Flowchart for the VICTOR-1 study. VRL = vinorelbine; CAPE = capecitabine. 3-4 adverse events (0.06%) per cycle. The 3 times weekly VRL schedule was selected based on pharmacokinetic data from phase IA and IB studies supporting the suitability of oral VRL doses of mg given 3 times a week with respect to drug exposure and steady-state drug concentrations (5, 6). This report presents data on the efficacy and toxicity of the oral metronomic VRL + CAPE combination in VICTOR-1 study patients aged 70 years. Patients and methods Patients Full details of the overall VICTOR-1 population have been reported previously (4). Patient inclusion criteria were: documented locally advanced or metastatic breast cancer; age 18 years; pre- or postmenopausal; previous treatment with anthracyclines and taxanes or not able to receive either or both of these agents; HER2-negative status or HER2-positive with cardiac contraindications to anti-her2 treatment; measurable or evaluable disease; life expectancy >12 weeks; ECOG performance status 2; adequate bone marrow, liver and renal function; International Normalized Ratio (INR) <3 at screening for patients taking warfarin; absence of cerebral or leptomeningeal metastases. All patients provided written informed consent. This analysis was conducted in the subgroup of patients aged 70 years. Study treatment Phase I of the VICTOR-1 trial determined the maximum tolerated dose (MTD) of metronomic VRL by analyzing the incidence of grade 3-4 adverse events in 3 groups of 3 patients each treated with increasing VRL doses (20 mg, 30 mg and 40 mg) in combination with a fixed dose of CAPE (500 mg tid) (Fig. 1); the MTD of VRL was 40 mg 3 times a week, given on alternate days after food (4). All patients who reached the 40 mg VRL dose level continued to receive that dosage until disease progression, refusal to continue the study, or unacceptable toxicity. One cycle was defined as 3 weeks of treatment. Response assessment Responses were assessed using the RECIST 1.0 criteria. The overall response rate (ORR) was expressed as the percentage of complete and partial responses (CR and PR) in the analyzed population. Time to progression (TTP) was defined as the interval between the start of the metronomic combination of VRL + CAPE and the time of disease progression. Toxicity assessment Hematological toxicity was evaluated by complete blood count every 3 weeks; renal and liver function by biochemistry at the beginning of each subsequent cycle. All toxicities were graded according to the National Cancer Institute Common Terminology Criteria of Adverse Events (NCI-CTCAE, version 3). Statistical analysis Standard descriptive statistics were used for detailing baseline characteristics and relevant safety and activity endpoints. Kaplan-Meier curves were used to describe time events. Results The VICTOR-1 study included 32 patients with advanced breast cancer enrolled from October 2009 to August Data on treatment toxicity and activity in the overall study population have been reported previously (4). Eighteen of

3 e6 Oral metronomic VRL + CAPE in elderly metastatic breast cancer patients TABLE I - Patient characteristics at baseline the enrolled patients (56.2%) were aged 70 years and were included in the current analysis (Tab. I). Four patients presented with 2 pre-existing comorbidities (hypertension + diabetes, hypertension + atrial fibrillation, hypertension + metabolic disorder, and hypertension + chronic ischemia, all in 1 patient each). All other patients had at least 1 comorbidity at enrolment, mainly hypertension. Concomitant drugs, mainly for cardiovascular disorders, were being taken by the majority of patients (77.7%). Eight patients (44%) had already received 1 chemotherapy regimens for metastatic disease at the time of study entry. Most patients (78%) presented with 2 metastatic sites. A total of 264 cycles of treatment were delivered (range 3-54); the median number of cycles per patient was 14. Tolerability Patients (n = 18) Age, years; median (range) 76 (70-84) ECOG performance status, n (%) (61) 2 7 (39) Stage at enrolment, n (%) Locally advanced 0 Metastatic 18 (100) Histology, n (%) Ductal carcinoma 16 (88) Lobular carcinoma 1 (6) Other 1 (6) Hormone receptor status, n (%) ER+/PR+ 13 (72) ER+/PR 4 (22) ER /PR 1 (6) HER2 status, n (%) Negative 12 (66) Positive 3 (17) Unknown 3 (17) No. of metastatic sites, n (%) 1 4 (22) 2 14 (78) Median DFI, months 56 Prior treatments, n (%) Anthracyclines 10 (56) Taxanes 9 (50) Anthracyclines + taxanes 9 (50) DFI = disease-free interval; ECOG = European Cooperative Oncology Group; ER = estrogen receptor; HER = human epidermal growth factor; PR = progesterone receptor. A total of 127 any-grade adverse events were observed. Grade 1-2 events occurred in 45.8% of patients and were mainly TABLE II - Summary of adverse events in elderly patients receiving metronomic vinorelbine + capecitabine Adverse events by grade Events per cycle (% of total cycles [n = 264]) Grade 1 76 (28.7) Nausea 16 (6.1) Asthenia 14 (5.3) Abdominal pain 13 (4.9) Diarrhea 6 (2.3) Myalgia 5 (1.9) Neuropathy 5 (1.9) Gastric pain 3 (1.1) Stomatitis 3 (1.1) Vomiting 3 (1.1) Anemia 2 (0.7) Hand-foot syndrome 2 (0.7) Elevated transaminases 1 (0.4) Hair loss 1 (0.4) Loss of appetite 1 (0.4) Sepsis 1 (0.4) Grade 2 45 (17.1) Asthenia 21 (7.9) Abdominal pain 5 (1.9) Anemia 5 (1.9) Nausea 3 (1.1) Hair loss 2 (0.7) Diarrhea 1 (0.4) Hand-foot syndrome 1 (0.4) Nail disorder 1 (0.4) Neuropathy 1 (0.4) Neutropenia 1 (0.4) Sepsis 1 (0.4) Stomatitis 1 (0.4) Taste alteration 1 (0.4) Vomiting 1 (0.4) Grade 3 4 (1.5) Neuropathy 2 (0.7) Anemia 1 (0.4) Diarrhea 1 (0.4) Grade 4 2 (0.7) Neutropenia 2 (0.7) grade 2 asthenia (7.9%), grade 1 nausea (6.1%), grade 1 asthenia (5.3%), grade 1 abdominal pain (4.9%), and grade 1 diarrhea (2.3%). The incidence of grade 3 (1.5%) and grade 4 (0.7%) adverse events was very low. These were mainly grade 3 neuropathy (0.7%) and grade 4 neutropenia (0.7%). Most adverse events developed during cycles 1-5 (cycle 1, 7.8%; cycle 2, 9.2%; cycle 3 & 4, 5.3%; cycle 5, 6.3%); the incidence of any-grade adverse events during subsequent cycles was <3.9%. Toxicities by severity are summarized in Table II. In 3/18 patients (17%), the VRL dose was reduced to 20 mg 3 times a week. In one case, the reason was grade 3

4 Cazzaniga et al e7 neuropathy developing at cycle 13, and in another case it was grade 2 vomiting and mucositis in cycle 10. The third patient had been enrolled in the VRL 50 mg cohort in phase I of VIC- TOR-1, which was subsequently closed for unacceptable toxicity, as described previously (4). Efficacy Median TTP was 10.5 months (range 1-40). The ORR was 33% (6/18 patients), and clinical benefit (CR + PR + stable disease for >24 weeks) was obtained in 12 patients (67%). Discussion In this analysis, elderly patients with advanced breast cancer showed a similar incidence of grade 1-2 adverse events (45.8% vs. 48.1%) as well as grade 3-4 events compared with the overall VICTOR-1 study population (4). No patient required blood transfusion or white cell growth factors. Compared with standard VRL and CAPE administration, the metronomic schedule was associated with a better tolerability profile overall. During use of the standard regimen, clinical study data show that neutropenia is often the doselimiting toxicity, and that grade 4 events can occur in up to 17.4% of patients (7). Grade 2 anemia has been reported in 15.5%-18.5% of patients receiving standard VRL + CAPE (7), but the rate in our study using an all-oral metronomic regimen of the same agents was only 4.1%. It has been suggested that the bone marrow of elderly patients is more sensitive to cytotoxic treatments, especially in those with multiple bone metastases (7). In our opinion, delivery of low, continuous doses of chemotherapy agents results in less damage to bone marrow function, making it possible to treat patients for a longer period with adequate doses, something that cannot be achieved with standard schedules. Metronomic chemotherapy reduces the level of toxicity and decreases, or even removes, the need for growth factor support to accelerate recovery from myelosuppression, facilitating a prolonged duration of treatment (4). The most problematic nonhematological toxicity in elderly patients is diarrhea, mainly in association with CAPE. The incidence of diarrhea in the subgroup of elderly patients from the VICTOR-1 study was very low. Similarly, other CAPEspecific toxicities usually observed with the standard schedule and dose, such as hand-foot syndrome and mucositis, were rare. Conversely, adverse events, including severe diarrhea, have necessitated CAPE dosage reduction when a standard schedule is used (8). Other chemotherapy options for elderly patients with metastatic disease are pegylated liposomal anthracyclines and nab-paclitaxel. These drugs are preferentially chosen for elderly patients because they do not require important concomitant drugs, such as steroids, which could have a negative impact on other comorbidities often present in older individuals, and antiemetic prophylaxis is not required in the days after chemotherapy. Data from a post-hoc analysis of 2 studies reported that the incidence of grade 3-4 adverse events was 78% with weekly nab-paclitaxel 100 mg/ m 2 and 100% at a dose of 150 mg/m 2 (9). These rates are higher than in our study, where the incidence of grade 3-4 adverse events per cycle with metronomic VRL and CAPE was very low (2.2%). Another option for elderly patients is pegylated liposomal doxorubicin. In a recently published randomized phase III study comparing pegylated liposomal doxorubicin with standard CAPE as first-line therapy in elderly women with advanced breast cancer, the overall incidence of grade 3-4 adverse events was 50% in patients treated with pegylated liposomal doxorubicin and 38% in those treated with standard CAPE; the incidence of grade 3 fatigue and grade 3 hand-foot syndrome was 13% and 16%, respectively (10). Regarding efficacy, the all-oral metronomic VRL + CAPE regimen was associated with an ORR of 33% in this group of elderly patients, and a clinical benefit rate of 67%. These results are similar to those obtained using different regimens, including those mentioned above. However, the small number of patients in the present analysis means that the data concerning clinical activity need to be interpreted with caution. Small sample size and the retrospective design are the main limitations of this study. However, it provides useful preliminary information on treatment options in an understudied and important group of metastatic breast cancer patients. The treatment schedule used in the VICTOR-1 trial is now being investigated in an ongoing phase II multicenter study in locally advanced or metastatic breast cancer (VICTOR-2). Studies of elderly patients are difficult, and many trials in this patient group have been closed prematurely due to slow accrual (8, 10). Analysis of patients aged 70 years in VICTOR-2 has been preplanned and will add to the body of evidence available to clinicians to help guide their treatment of this important patient subgroup. Conclusion The all-oral metronomic combination of VRL and CAPE had an acceptable efficacy profile and was well tolerated in metastatic breast cancer patients aged 70 years. In particular, the tolerability of this regimen appeared to be better than that of standard treatment schedules. Data from the ongoing VICTOR-2 study will provide more definitive information about the role of metronomic chemotherapy in elderly patients with advanced breast cancer, along with data on QoL and treatment adherence. Abbreviations CAPE CR MTD NCI-CTCAE ORR PR QoL tid TTP VRL capecitabine complete response maximum tolerated dose National Cancer Institute Common Terminology Criteria of Adverse Events overall response rate partial response quality of life three times daily time to progression vinorelbine

5 e8 Oral metronomic VRL + CAPE in elderly metastatic breast cancer patients Disclosures Acknowledgment and financial support: Editorial assistance in the preparation of this manuscript was provided by Nicola Ryan, an independent medical writer, on behalf of Springer Healthcare Communications. This assistance was supported by Pierre Fabre Pharma s.r.l., Milan, Italy. Conflict of interest: The authors state that they have no conflicts of interest to declare. References 1. Wildiers H, Kunkler I, Biganzoli L, et al; International Society of Geriatric Oncology. Management of breast cancer in elderly individuals: recommendations of the International Society of Geriatric Oncology. Lancet Oncol. 2007;8(12): Bocci G, Kerbel RS. Pharmacokinetics of metronomic chemotherapy: a neglected but crucial aspect. Nat Rev Clin Oncol May 17. doi: /nrclinonc [Epub ahead of print] 3. Colleoni M, Rocca A, Sandri MT, et al. Low-dose oral methotrexate and cyclophosphamide in metastatic breast cancer: antitumor activity and correlation with vascular endothelial growth factor levels. Ann Oncol. 2002;13(1): Cazzaniga ME, Torri V, Villa F, et al. Efficacy and safety of the alloral schedule of metronomic vinorelbine and capecitabine in locally advanced or metastatic breast cancer patients: the phase I-II VICTOR-1 study. Int J Breast Cancer. 2014;2014: Briasoulis E, Pappas P, Puozzo C, et al. Dose-ranging study of metronomic oral vinorelbine in patients with advanced refractory cancer. Clin Cancer Res. 2009;15(20): Briasoulis E, Aravantinos G, Kouvatseas G, et al. Dose selection trial of metronomic oral vinorelbine monotherapy in patients with metastatic cancer: a Hellenic Cooperative Oncology Group clinical translational study. BMC Cancer. 2013; 13(1): Hess D, Thürlimann B, Pagani O, et al; Swiss Group of Clinical Cancer Research (SAKK). Capecitabine and vinorelbine in elderly patients (> or = 65 years) with metastatic breast cancer: a phase I trial (SAKK 25/99). Ann Oncol. 2004;15(12): Bajetta E, Procopio G, Celio L, et al. Safety and efficacy of two different doses of capecitabine in the treatment of advanced breast cancer in older women. J Clin Oncol. 2005;23(10): Aapro M. Tjulandin, Bhar P, Gradishar W. Weekly nab-pacliataxel is safe and effective in 65 years old patients with metastatic breast cancer: a post-hoc analysis. Breast. 2011;20(5): Smorenburg CH, de Groot SM, van Leeuwen-Stok AE, et al. A randomized phase III study comparing pegylated liposomal doxorubicin with capecitabine as first-line chemotherapy in elderly patients with metastatic breast cancer: results of the OMEGA study of the Dutch Breast Cancer Research Group BOOG. Ann Oncol. 2014;25(3):