Severe and prolonged lymphopenia observed in patients treated with bendamustine and erlotinib for metastatic triple negative breast cancer.

PURPOSE: Triple negative breast cancers (TNBC) frequently have high epidermal growth factor receptor (EGFR) expression and are sensitive to DNA-damaging agents. Improved therapies are needed for this aggressive malignancy. PATIENTS AND METHODS: We performed a phase I trial of bendamustine and erlotinib, an EGFR tyrosine kinase inhibitor, in patients with metastatic TNBC, ECOG performance status ≤2, and ≤1 prior chemotherapy for metastatic disease. Each 28-day cycle included intravenous bendamustine on days 1, 2 and oral erlotinib on days 5-21 with dose escalation according to a 3 + 3 phase I study design. Dose-limiting toxicity (DLT) was determined by toxicities related to study therapy observed during cycle 1. RESULTS: Eleven patients were treated, 5 on dose level 1 and 6 on dose level 2. One patient had DLT on dose level 2. However, cumulative toxicities were observed, including grade 3/4 lymphopenia in 91 % (95 % CI 0.59-0.998) with progressively decreased CD4 counts and grade ≥3 infections in 36 % (95 % CI 0.11-0.69) of patients. CONCLUSIONS: Combination therapy with bendamustine and erlotinib causes excessive toxicity with severe, prolonged lymphopenia, depressed CD4 counts, and opportunistic infections and should not be pursued further. Future trials of bendamustine combinations in TNBC patients should account for potential cumulative lymphocyte toxicity necessitating patient monitoring during and after treatment.

Phase II trial of exemestane in combination with fulvestrant in postmenopausal women with advanced, hormone-responsive breast cancer.

INTRODUCTION: Exemestane, the irreversible steroidal aromatase inhibitor, and fulvestrant, the pure estrogen antagonist, are active as single drugs in postmenopausal women with advanced hormone-responsive breast cancer. We designed a phase II study with the purpose of determining whether combining these 2 drugs with different and potentially complementary mechanisms of action will improve the clinical benefit. PATIENTS AND METHODS: Forty postmenopausal women with hormone-responsive advanced breast cancer received intramuscular injection of fulvestrant 250 mg every 28 days in combination with daily exemestane 25 mg until disease progression. We examined the influence of fulvestrant on exemestane pharmacokinetics and the effect of exemestane and fulvestrant on serum IGF-1 (insulin-like growth factor 1) and IGFBP-3 (IGF-binding protein 3) levels. RESULTS: The observed proportion of patients free of progressive disease at 6 months after the initiation of treatment with exemestane and fulvestrant was 50%, a rate similar to that achieved with single-agent exemestane or fulvestrant in the first- or second-line setting. Pharmacokinetics parameters showed that coadministration of fulvestrant did not result in clinically relevant changes in exemestane plasma concentrations. A comparison of IGF-1 and IGFBP-3 levels demonstrated the increase of 35% and 12%, respectively, in mean levels from baseline to day 120. CONCLUSIONS: The combination of exemestane and fulvestrant did not improve clinical benefit. The observed lack of improved efficacy was not related to altered drug exposure.

A phase II trial of trastuzumab in combination with low-dose interleukin-2 (IL-2) in patients (PTS) with metastatic breast cancer (MBC) who have previously failed trastuzumab.

Trastuzumab mediates the lysis of HER2-expressing breast cancer cell lines by interleukin-2 (IL-2) primed natural killer (NK) cells. We hypothesized that IL-2 would augment the anti-tumor effects of trastuzumab in MBC in patients who had progressed on or within 12 months of receiving a trastuzumab-containing regimen. Secondary objectives were to measure antibody-directed cellular cytotoxicity (ADCC) against HER2 over-expressing target cells, and to measure serum cytokines. Patients received trastuzumab (4 mg/kg intravenously (IV)) every 2 weeks in combination with daily low-dose IL-2 (1 million IU/m(2) subcutaneously (SC)) and pulsed intermediate-dose IL-2 (12 million IU/m(2) SC). Samples were analyzed for NK cell expansion and ADCC against a HER2-positive breast cancer cell line. In addition, interferon-gamma (IFN-gamma), mRNA expression in peripheral blood mononuclear cells (PBMC) and the following serum cytokines were measured: IFN-gamma, monokine-induced by IFN-gamma (MIG), and interferon-inducible protein ten (IP-10). The median number of treatment cycles was four (range 1-23) and the treatment was well tolerated. There were no objective responses. NK cells were not expanded and ADCC was not enhanced. Eight (62%) patients had a twofold or higher increase in mRNA transcript for IFN-gamma, two (15%) patients had elevated serum levels of IFN-gamma and 12 (92%) had increases angiogenic MIG and IP-10. In trastuzumab-refractory patients adding IL-2 did not produce responses and did not result in NK cell expansion. However, these patients had the ability to respond to IL-2 as evidenced by increases in IFN-gamma transcripts and chemokines. The lack of NK cell expansion may explain the absence of clinical benefit.

Randomized phase II adjuvant trial of dose-dense docetaxel before or after doxorubicin plus cyclophosphamide in axillary node-positive breast cancer.

PURPOSE: An anthracycline-based combination followed by, or combined with, a taxane is the sequence used in most adjuvant chemotherapy regimens. We hypothesized that administering the taxane before the anthracycline combination would be associated with fewer dose reductions and delays than the reverse sequence. To test this hypothesis, a randomized phase II multicenter adjuvant chemotherapy trial was performed. PATIENTS AND METHODS: Fifty-six patients with axillary node-positive, nonmetastatic breast cancer were randomly assigned either to group A (docetaxel [DOC] 75 mg/m(2) intravenously [IV] every 14 days for four cycles followed by doxorubicin 60 mg/m(2) and cyclophosphamide 600 mg/m(2) [AC] IV every 14 days for four cycles); or to group B (AC followed by DOC) at the identical doses and schedule. Pegfilgrastim 6 mg subcutaneous injection was administered 1 day after the chemotherapy in all treatment cycles. The primary objective was to administer DOC without dose reductions or delays before or after AC and calculate the relative dose intensity (RDI) of DOC and AC. RESULTS: The majority of toxicities were grade 0 to 2 irrespective of sequence. The RDI for DOC was 0.96 and 0.82, respectively, in groups A (DOC followed by AC) and B (AC followed by DOC), with more frequent dose reductions occurring in group B (46% v 18%). The RDI for AC was 0.95 and 0.98 in groups A and B, respectively. CONCLUSION: The administration of DOC before AC results in fewer DOC dose reductions and a higher RDI than the reverse sequence. Larger trials evaluating the sequence of DOC before anthracyclines are justified.