Sapanisertib Plus Exemestane or Fulvestrant in Women with Hormone Receptor-Positive/HER2-Negative Advanced or Metastatic Breast Cancer

PURPOSE

This open-label, multicenter, phase IB/II study evaluated sapanisertib, a dual inhibitor of mTOR kinase complexes 1/2, plus exemestane or fulvestrant in postmenopausal women with hormone receptor-positive (HR⁺)/HER2-negative (HER2^-) advanced/metastatic breast cancer.

PATIENTS AND METHODS

Eligible patients had previously progressed on everolimus with exemestane/fulvestrant and received ≤3 (phase IB) or ≤1 (phase II) prior chemotherapy regimens. Patients received sapanisertib 3 to 5 mg every day (phase IB), or 4 mg every day (phase II) with exemestane 25 mg every day or fulvestrant 500 mg monthly in 28-day cycles. Phase II enrolled parallel cohorts based on prior response to everolimus. The primary objective of phase II was to evaluate antitumor activity by clinical benefit rate at 16 weeks (CBR-16).

RESULTS

Overall, 118 patients enrolled in phase IB (n = 24) and II (n = 94). Five patients in phase IB experienced dose-limiting toxicities, at sapanisertib doses of 5 mg every day (n = 4) and 4 mg every day (n = 1); sapanisertib 4 mg every day was the MTD in combination with exemestane or fulvestrant. In phase II, in everolimus-sensitive versus everolimus-resistant cohorts, CBR-16 was 45% versus 23%, and overall response rate was 8% versus 2%, respectively. The most common adverse events were nausea (52%), fatigue (47%), diarrhea (37%), and hyperglycemia (33%); rash occurred in 17% of patients. Molecular analysis suggested positive association between AKT1 mutation status and best treatment response (complete + partial response; P = 0.0262).

CONCLUSIONS

Sapanisertib plus exemestane or fulvestrant was well tolerated and exhibited clinical benefit in postmenopausal women with pretreated everolimus-sensitive or everolimus-resistant breast cancer.

Abstract PS17-20: Response to a modified whole tumor cell targeted immunotherapy in patients with advanced breast cancer correlates with tumor grade

Background: SV-BR-1-GM is a GM-CSF transfected breast cancer cell line, exceptional for having antigen-presenting capability and expressing both HLA I and II. The parent cell line, SV-BR-1, was derived from a patient with grade II (moderately differentiated) breast cancer. We report molecular characterization of SV-BR-1-GM, noting it retains features of a grade II tumor, and report enhanced disease control in patients with grade I or II breast cancer.Methods: SV-BR-1 and SV-BR-1-GM were characterized molecularly using RNAseq and proteomic analyses. We treated 23 evaluable patients with recurrent and/or metastatic breast cancer refractory to standard therapy. The SV-BR-1-GM regimen included cyclophosphamide 300 mg/m2 2-3d prior to intradermal injection of SV-BR-1-GM (20-40x106 cells divided into 4 sites) and IFNα into the inoculation sites (10,000 IU/site) about 48 and 96 hours subsequently. Cycles were q2 weeks x3 then qmo x 3 (clinical trial NCT03066947). Eleven patients were treated with the above regimen in combination with a PD-1 inhibitor (pembrolizumab or INCMGA00012) (clinical trial NCT03328026). Disease response was evaluated radiographically q3 mo and as clinically indicated. Results: To estimate the tumor grade represented by the SV-BR-1-GM cell line, we developed a score we refer to as Relative Molecular Grade (RMG). SV-BR-1-GM is most similar to the MDA-MB-468 cell line (RMG of 52.1), which was classified as Basal A phenotype. Basal A cancers are less aggressive than Basal B but more aggressive than Luminal, suggesting that SV-BR-1-GM may have retained features of a grade II breast cancer. We also noted that SV-BR-1-GM expresses both Class I (HLA-A, B & C) and Class II (HLA-DR and -DP) molecules, and that the HLA-DR expression is enhanced by treatment with IFNγ. SV-BR-1-GM expressed 31 genes which are overexpressed in breast cancer, 8 cancer-testis antigens and 3 genes expressed in breast tissue. In 30 patients treated with the SV-BR-1-GM regimen (19 with the SV-BR-1-GM regimen alone, 4 who began on the SV-BR-1-GM regimen and transitioned to combination with a PD-1i, and 7 with combination therapy alone) there were 7 with grade II breast cancer and 1 with grade I breast cancer (Table). These patients were heavily pre-treated with an average of 10 prior regimens. While only one patient with grade III cancer showed disease control, 75% of the patients with grade I or II tumors showed disease control. Patients remained on study for up to 259 days.Conclusions: SV-BR-1-GM appears to retain characteristics of a moderately differentiated breast cancer, expresses multiple potential tumor antigens, and can elicit disease control especially in patients with grade I and II breast cancer.

TablePatients with Grade I/II TumorsCharacteristicSV-BR-1-GM Regimen Alone(n=6)SV-BR-1-GM Regimen + PD-1i(n=3)All Patients(n=8)Age64 ± 767 ± 465 ± 7Mean Prior Systemic Regimens6 (range 1-20)15 (range 14-15)10 (range 1-20)% ER/PR +80%100%86%% Her2/neu +0%33%14%% Triple Negative20%0%14%Delayed-type Hypersensitivity83%100%88%Disease Control Rate*67%100%75%Days on Study (Range)94 (32-181)189 (133-259)141 (32-259)•Includes CR, PR, SD (including minor responses and mixed responses)

Citation Format: William Williams, Shaker R Dakhil, Carmen Calfa, Jarrod P Holmes, Saveri Bhattacharya, Jason Lukas, Elizabeth Tan-Chiu, George E Peoples, Vivek G Sunkari, Markus D Lacher, Charles L Wiseman. Response to a modified whole tumor cell targeted immunotherapy in patients with advanced breast cancer correlates with tumor grade [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS17-20.

Breast cancer grade and clinical benefit in patients with advanced breast cancer treated with an engineered whole tumor cell-targeted immunotherapy alone or in combination with checkpoint inhibition

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Background: SV-BR-1 is a breast cancer cell line derived from a grade II (moderately differentiated) tumor. SV-BR-1 was transfected with the CSF2 gene (encoding GM-CSF) to form SV-BR-1-GM. SV-BR-1-GM expresses HLA class I & II antigens and has functional antigen-presenting cell activity, directly stimulating CD4+ T cells in an HLA-DR restricted fashion. The SV-BR-1-GM regimen consists of low-dose cyclophosphamide (300 mg/m2) to reduce immune suppression, intradermal inoculation with irradiated SV-BR-1-GM (20x106 cells divided into 4 sites) and interferon-α2b (10,000 IU into each inoculation site ~2 & 4 days later) to boost the response. Here, we evaluate the impact of tumor grade on clinical benefit following treatment with the SV-BR-1-GM regimen. Methods: Patients with advanced breast cancer were treated with either the SV-BR-1-GM regimen alone or with the SV-BR-1-GM regimen with pembrolizumab. For the SV-BR-1-GM regimen alone, cycles were administered every 2 weeks x 3 and then monthly, while combination with pembrolizumab (200 mg IV 1-5 days following SV-BR-1-GM inoculation) administered cycles every 3 weeks. Tumor restaging was every 6-12 weeks. Results: 33 patients were enrolled. The treatment was generally safe with inoculation site pruritis, erythema and induration the most common adverse events. 23 patients had grade III (poorly differentiated) tumors, 9 had grade II tumors and one had a grade I (well differentiated) tumor. None of the patients with grade III tumors exhibited clinical benefit. 7 patients with grade I/II tumors received the SV-BR-1-GM regimen alone, 2 received the SV-BR-1-GM regimen with pembrolizumab and 1 received both regimens. As noted in the Table, 7 patients experienced clinical benefit including all 3 patients treated in combination with pembrolizumab. This included 6 patients with stable disease and one with a partial response. Conclusions: The SV-BR-1-GM regimen with or without pembrolizumab appears safe and able to induce clinical benefit even in very heavily pre-treated patients with low or intermediate grade advanced breast cancer. Clinical trial information: NCT03328026 . [Table: see text]

Safety and efficacy of a phase I/IIa trial (NCT03066947) of a modified whole tumor cell targeted immunotherapy in patients with advanced breast cancer

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Background: SV-BR-1-GM is a GM-CSF transfected breast cancer cell line which expresses HLA class I & II antigens and has functional antigen-presenting cell activity. Prior studies suggest that partial matching of the HLA type of the patient with SV-BR-1-GM may be predictive of tumor regression. Methods: Subjects received low-dose cyclophosphamide 2-3d prior to ID injection of irradiated SV-BR-1-GM (20 million cells divided into 4 sites) and interferon-α into the inoculation sites ~2 & 4 days subsequently. Cycles were q2 weeks x 3 then q mo. Results: A total of 30 patients were screened and 23 inoculated (Table). The patients were heavily pretreated with a median of 4 prior chemo/biological therapy regimens. There were no serious or unexpected adverse events. Local injection-site irritation was the most common toxicity. Objective tumor regression was seen in 3 patients, all of whom matched SV-BR-1-GM at least at one HLA locus: one patient with regression or clearing of 20 lung metastases; one with reduction in cutaneous involvement of the breast from 80% to 30% and one with regression of a breast lesion. Another 3 patients had decreases in circulating cancer-associated macrophage-like cells (CAMLs), which has been shown to correlate with tumor stage. They also all matched at least at one HLA allele. Circulating tumor cells and circulating epithelial cells were present in low numbers and tended to parallel trends in CAMLs which were present in larger numbers. CAMLs in 21/23 patients stained positive for PD-L1. Patients with tumor regression had robust DTH responses to SV-BR-1-GM. Conclusions: SV-BR-1-GM in this regimen appears to be safe and well-tolerated and is associated with objective regression of metastatic breast cancer and/or with decreases in circulating cancer-associated cells in 6/23 (26%) or patients. HLA matching may be a predictor of response. Clinical trial information: NCT03066947. [Table: see text]

Abstract P2-09-09: Initial safety and efficacy of a phase I/IIa trial of a modified whole tumor cell targeted immunotherapy in patients with advanced breast cancer

Background: SV-BR-1-GM is a GM-CSF transfected breast cancer cell line which expresses HLA class I & II antigens. In a previous clinical trial, a partial response of widely metastatic breast cancer was seen in a patient who matched SV-BR-1-GM at HLA-DRB3*02:02. Here we report the safety and efficacy analysis with immunologic correlates of response in the initial patients in a phase I/IIa trial of SV-BR-1-GM in patients with advanced breast cancer

Methods: This phase I/IIa trial enrolled patients with recurrent and/or metastatic breast cancer refractory to standard chemotherapy/targeted-therapy. Patients received low-dose cyclophosphamide 2-3d prior to intradermal injection of SV-BR-1-GM (20x106 cells divided into 4 sites) and interferon-α into the inoculation sites (10,000 IU/site) ˜2 & 4 days subsequently. Cycles were 2 weeks x3 then q mo x 3. Adverse events (AE) were evaluated after each inoculation and graded via CTCAE v4.03. Immunologic response was measured by delayed type hypersensitivity (DTH) after each inoculation. Disease response was evaluated radiographically q3 mo and as clinically indicated (clinical trial NCT03066947).

Results: To date, twenty-two patients have been enrolled and 17 have been inoculated for a total of 39 SV-BR-1-GM inoculations given. Per inoculation, the maximum related AE was grade 1 in 64%, grade 2 in 7.7%, and grade 3 in 7.7%. There were no related grade >3 or unexpected AE. Efficacy data is available on the first six (Table). Tumor regression was seen in 2 patients. 01-002 presented with liver, bone and 20 classic miliary lung metastases (up to 9mm). This subject previously received 7 chemotherapy regimens. She matched SV-BR-1-GM at Class I & II HLA loci. Imaging at 3 mo showed virtually complete regression of all 20 identifiable lesions in the lungs. This response was maintained at 6 mo but the subject was taken off protocol because of disease progression (liver and bone). 01-005, matching HLA-A*24:02, had notable regression of cutaneous lesions, but progressed in pleural and pericardial effusions, had irreversible cardiac arrest (unlikely related). DTH increased in 01-002 from 4mm (first dose) to 47mm (8th dose). Three of 3 patients evaluated developed antibodies responses (as measured by flow cytometry with SV-BR-1) including 01-002. Interleukin 8 also increased in 01-002.

Conclusions: SV-BR-1-GM in this regimen appears to be safe and well-tolerated. In this initial exploratory analysis, SV-BR-1-GM can produce regression of pre-treated metastatic breast cancer correlating with an immunologic response. HLA matching is being evaluated as a predictor of response.

PatientAgeMetastatic Sites# Prior RegimensHLA Matches# of CyclesTumor Regression?01-00146Pleura, Lymph Nodes7 chemo/bio, 5 hormonalDRB3*02:021No01-00273Lung, Liver, Bone6 chemo, 1 hormonalA*24:02, DRB3*02:028Lungs01-00554Lymph nodes, Pleura, Skin3 chemo/bioA*24:022Skin02-00170Lymph nodes1 chemo/bioNone1No02-00361Bone, Brain3 chemoNone6No02-00474Lymph nodes, Cutaneous3 chemo/bio, 1 hormonalDRB3*02:022Lost to Follow-up

Citation Format: Bhattacharya S, Holmes JP, Calfa C, Lukas J, Tan-Chiu E, Clifton GT, Peoples GE, Lacher M, Wiseman CL, Williams WV. Initial safety and efficacy of a phase I/IIa trial of a modified whole tumor cell targeted immunotherapy in patients with advanced breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-09-09.

Abstract PD1-09: Phase 2 safety and efficacy results of TAK-228 in combination with exemestane or fulvestrant in postmenopausal women with ER-positive/HER2-negative metastatic breast cancer previously treated with everolimus

Background: TAK-228 is an investigational, oral and highly selective ATP-competitive inhibitor of TORC1/2. Targeting the PI3K/AKT/mTOR pathway with the dual TORC1/2 inhibitor TAK-228 may restore sensitivity to endocrine therapies in patients (pts) with breast cancer who have progressed on the combination of an endocrine agent plus a TORC1 inhibitor. Here we report data from the phase 2 portion of a phase 1b/2 study of TAK-228 plus exemestane (E) or fulvestrant (F).

Methods: Postmenopausal women with ER+ and HER2-, inoperable or metastatic breast cancer (MBC) following everolimus (EVE) plus E or F after progression, received oral TAK-228 (4 mg QD) plus E (25 mg QD) or F (500 mg monthly) for 28-day cycles until progressive disease (PD) or unacceptable toxicity (NCT02049957). Pts were enrolled into parallel cohorts based on prior response to EVE plus E or F and were given the same prior therapy (E or F) at their established dose: EVE-sensitive, defined as disease progression after complete response (CR), partial response (PR), or ≥6 mos stable disease (SD); or EVE-resistant, defined as disease progression without a CR or PR, or after <6 mos SD. Primary endpoint was clinical benefit rate at 16 wks (CR, PR, or SD at 16 wks; CBR-16). Secondary endpoints included CBR at 24 wks (CBR-24), overall response rate (ORR), progression-free survival (PFS), overall survival (OS) and safety.

Results: From Oct 2015 to Dec 2017, 94 pts were enrolled. Median age was 58 y (range 32–83). At baseline, most pts (67%) had stage IV disease and others were stage IA–IIIC (24%), other (3%) or unknown (5%); 94% of EVE-sensitive (93% E vs 100% F) and 88% of EVE-resistant pts (91% E vs 75% F) had received ≥4 prior lines of therapy. Pts received a median of 3 cycles (1–15) of TAK-228. At data cutoff (24 Apr 2018), 98% of pts had discontinued treatment, mainly due to PD (76%) or adverse events (AEs; 14%). CBR-16 was 41% (n=21) in EVE-sensitive and 26% (n=11) in EVE-resistant pts (table). CBR-24 was 24% in EVE-sensitive (19% E vs 50% F) and 23% in EVE-resistant (23% E vs 25% F) pts. Eleven of 21 pts who achieved CBR-16 also achieved CBR-24 (6 SD, 5 PR) in the EVE-sensitive cohort and 8 of 11 pts in the EVE-resistant cohort (6 SD, 2 PR). The ORR was 12% in EVE-sensitive pts and 9% in EVE-resistant pts (table). Median PFS (95% CI) was 4.1 mos (2.2–5.5) and 3.4 mos (1.9–5.4), and median OS (95% CI) was 15.9 mos (14.1–19.5) and 14.0 mos (13.0–16.0) in the EVE-sensitive and -resistant cohorts, respectively. Drug-related any grade and grade ≥3 AEs were seen in 90% and 29% of pts, respectively. Most common drug-related any grade AEs were nausea (50%), fatigue (38%), hyperglycemia and diarrhea (each 29%); 22% of pts reported a serious AE. No deaths were reported. Treatment is ongoing in two pts.

Conclusion: TAK-228 plus E or F showed modest clinical benefit in pts with previously treated, EVE-sensitive or -resistant MBC, with an acceptable safety profile.

 EVE-sensitive (N=51)EVE-resistant (N=43) TAK-228+TAK-228+Best response, n (%)E (n=43)F (n=8)E (n=35)F (n=8)ORR=CR+PR4 (9)2 (25)3 (9)1 (13)CR001 (3)0PR4 (9)2 (25)2 (6)1 (13)CBR-1617 (40)4 (50)9 (26)2 (25)

Citation Format: Diamond JR, Potter D, Salkeni M, Silverman P, Haddad T, Forget F, Awada A, Canon J-L, Danso M, Lortholary A, Bourgeois H, Tan-Chiu E, Patel C, Neuwirth R, Leonard EJ, Lim B. Phase 2 safety and efficacy results of TAK-228 in combination with exemestane or fulvestrant in postmenopausal women with ER-positive/HER2-negative metastatic breast cancer previously treated with everolimus [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD1-09.

Abstract CT171: Safety and efficacy of a whole-cell targeted immunotherapy for breast cancer: Preliminary findings

The purpose of this study is to evaluate the safety and preliminary efficacy of a targeted immunotherapy for breast cancer based on SV-BR-1-GM, a breast cancer cell line modified to secrete GM-CSF. The regimen used includes low dose cyclophosphamide (300 mg/m2) 2-3 days prior to inoculation to reduce immune suppression; irradiated SV-BR-1-GM (20,000 cGy) dosed intradermally (ID) in 4 sites (~20x106 cells total); and post-inoculation interferon-α (10,000 units ID into the SV-BR-1-GM inoculation sites) 2±1 and 4±1 days later. Dosing is every 2 weeks for the first month, then monthly for up to one year. This regimen was used in a prior study in 4 evaluable patients with advanced cancer (3 breast and 1 ovarian) and was safe and well tolerated. One patient, who had a partial response of widely metastatic breast cancer, was found to match SV-BR-1-GM at an MHC class II allele (HLA-DRB3*02:02).

This regimen is being used in a clinical trial (NCT03066947 in ClinicalTrials.gov) in patients with advanced breast cancer. To date 7 patients with metastatic breast cancer have been recruited and 6 dosed with evidence of tumor response in 2 patients. Ages ranged from 46-73. Time from initial diagnosis ranged from 2 - 12 years. The number of prior chemotherapy or biological therapy regimens ranged from 3-7. Treatment was generally safe and well tolerated. The majority of adverse events were limited to local irritation at the injection sites. No serious adverse events related to SV-BR-1-GM treatment have been reported and no new or unexpected safety issues related to SV-BR-1-GM have been observed. Two patients dropped out after a single cycle of treatment. One patient with inflammatory breast cancer dropped out after 2 treatments due to worsening breast inflammation. One patient appeared to be responding in the breast after the first treatment, with regression of soft tissue lesions in the breast, but developed a worsening pleural and pericardial effusions shortly after the second treatment with the development of pulseless electrical activity and was unable to be resuscitated. One patient has received 5 cycles of therapy and is ongoing. One patient had a notable response. For this 73-year-old woman with breast cancer diagnosed in 1995 with liver and lung metastases and 7 prior rounds of chemotherapy, after 3 months of treatment her scans noted “a clear response in the multiple bilateral pulmonary nodules” indicating that several lung tumors had disappeared or decreased in size. This response was maintained after 6 months. The liver tumors were stable to slightly increased at 3 months, and then progressed after 6 months. This patient matched with SV-BR-1-GM at 2 HLA loci (HLA-A*24:02 and HLA-DRB3*02:02).

The regimen used in this study has shown early evidence of activity in these patients with late stage, heavily pre-treated metastatic breast cancer. HLA matching may be useful in predicting those patients most likely to respond.

Citation Format: Jarrod P. Holmes, Elizabeth Tan-Chiu, Charles L. Wiseman, Markus D. Lacher, George Peoples, William V. Williams. Safety and efficacy of a whole-cell targeted immunotherapy for breast cancer: Preliminary findings [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr CT171.

Abstract PD5-11: Not presented

This abstract was not presented at the symposium.

Abstract P1-13-12: Quality of life and patient-reported outcomes in US patients enrolled in the MONALEESA-2 study

Background: Improvement to and maintenance of the highest possible health-related quality of life (QoL), in addition to disease control, are key goals of treatment in patients with advanced breast cancer (ABC). Endocrine therapy is preferred as first-line therapy in ABC because of its preferable safety profile compared with chemotherapy. In the MONALEESA-2 study, the cyclin-dependent kinases 4 and 6 inhibitor ribociclib, in combination with letrozole, significantly extended progression-free survival (PFS) compared with placebo + letrozole in patients with hormone receptor–positive (HR+), human epidermal growth factor receptor 2–negative (HER2−) ABC. Patient-reported outcomes demonstrated similar QoL among patients in both treatment groups. Here, we present data from US patients enrolled in the MONALEESA-2 study on overall QoL as well as individual domains.

Methods: Postmenopausal women (N=668) with HR+, HER2− ABC who did not receive prior systemic treatment for ABC and had an Eastern Cooperative Oncology Group performance status score of ≤1, adequate bone marrow and organ function, and no history of active cardiac dysfunction were randomized 1:1 to receive either ribociclib (600 mg/d, 3 weeks on/1 week off) + letrozole (2.5 mg/d, continuous) or placebo + letrozole. The primary end point was locally assessed PFS. Quality of life was reported using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 (EORTC QLQ-C30), the EuroQol 5-domain 5 level (EQ-5D-5L) visual analog scale (VAS) of overall health, and the breast symptom score of the EORTC QLQ-Breast Cancer 23 (EORTC QLQ-BR23) module. Data cutoff in this analysis was January 29, 2016.

Results: Patient characteristics and QoL survey reports were well balanced across treatment groups in US patients (n=213). The global health status/QoL scores of the EORTC QLQ-C30 were maintained between groups, and improved over time in the ribociclib group (mean ± standard deviation [SD] score at baseline, 69.1 ± 19.0; at 8 months, 71.3 ± 18.2; and at 16 months, 73.0 ± 16.0) and the placebo group (mean ± SD score at baseline, 69.9 ± 20.0; at 8 months, 75.9 ± 19.2; and at 16 months, 77.0 ± 15.0), which was consistent with scores in the overall population. At 16 months, the proportion of patients who did not experience ≥10% deterioration of all QoL scores was similar among treatment groups.

Quality of Life Outcomes of US Patients in the MONALEESA-2 Study at 16 MonthsOutcomeTreatment, nPatients without ≥10% deterioration in score, % (95% CI, %)EORTC QLQ-C30  Global health status/QoLRIB + LET, 2664.0 (49.4–75.4) PBO + LET, 3550.5 (36.2–63.2)Physical functioningRIB + LET, 2175.7 (62.6–84.7) PBO + LET, 1773.1 (57.2–83.9)Emotional functioningRIB + LET, 2271.6 (58.6–81.2) PBO + LET, 3159.7 (45.7–71.2)Social functioningRIB + LET, 1780.1 (68.5–87.8) PBO + LET, 2660.2 (44.1–73.0)EORTC QLQ-BR23 breast symptom scoreRIB + LET, 888.0 (76.6–94.0) PBO + LET, 886.2 (70.6–93.9)EQ-5D-5L VAS of overall healthRIB + LET, 1386.6 (76.9–92.4) PBO + LET, 1873.4 (56.8–84.4)LET, letrozole; PBO, placebo; RIB, ribociclib.

Conclusions: Addition of ribociclib to letrozole in US patients enrolled in MONALEESA-2 led to significant prolongation of PFS while maintaining QoL.

Citation Format: Tolaney SM, Tan-Chiu E, Truica C, Volas-Redd G, Shtivelband M, Dalal AA, Chandiwana D, Hortobagyi G. Quality of life and patient-reported outcomes in US patients enrolled in the MONALEESA-2 study [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-13-12.

Abstract OT3-06-07: A phase I/II dose escalation and expansion study to investigate the safety, pharmacokinetics, pharmacodynamics and clinical activity of GSK525762 in combination with fulvestrant in subjects with ER+ breast cancer

Background:

Advanced or metastatic ER+BC (estrogen receptor positive breast cancer) is an incurable illness that will prove fatal for most afflicted women. Current standards of care include endocrine, targeted, and chemotherapy. Preclinical data suggest that altering the expression of the estrogen receptor (ER) as well as other ER-responsive genes may provide therapeutic benefit for women for whom endocrine therapy alone has proven inadequate. The bromodomain (BRD) and extra-terminal (BET) family of proteins (BRD2, BRD3, BRD4 and BRDT) bind to acetyl-histone residues and epigenetically control transcription of genes driving cell survival and proliferation. BET proteins have been implicated in carcinogenesis and treatment resistance in multiple tumors including ER+BC, and are a novel target for therapy in breast cancer. GSK525762 is a pan-BET inhibitor that has shown strong synergistic activity with fulvestrant in killing ER+BC cells in vitro and in xenograft models. The combination of BET agents with endocrine therapy may provide therapeutic benefit and restore sensitivity to ER targeting agents like fulvestrant.

Trial Design & Specific Aims:

This study is a Phase I/II dose-escalation, expansion (Phase I) and randomized control (Phase II) study with oral administration of GSK525762 in combination with fulvestrant in advanced or metastatic ER+BC subjects, whose disease has progressed on prior treatment with at least one line of endocrine therapy.

Phase I of the study is designed as parallel single arms to determine a recommended Phase 2 dose (RP2D) based on safety, tolerability, pharmacokinetic, and efficacy profiles in two distinct populations of ER+ breast cancer:

Subjects with disease that relapsed during treatment or within 12 months of adjuvant therapy with an AI, OR disease that progressed during treatment with an AI for advanced/metastatic disease.

OR

Subjects with disease that progressed during treatment with the combination of a CDK4/6 inhibitor plus letrozole for advanced or metastatic disease.

Phase II of the study is a randomized, double-blind, placebo-controlled cohort, designed to evaluate the efficacy of the combination.

Key Eligibility Criteria: Patients must have received <3 lines of systemic anti-cancer therapy (≤1 line of chemo), measurable disease, and PS 0-1.

Statistical Methods: A modified toxicity probability interval (mTPI) design will be used to monitor safety. A Bayesian adaptive design will be used to evaluate efficacy in Phase 1.

Present and Target Accrual: Target enrolment will be ˜300 subjects across ˜50 sites worldwide. To date, 2 subjects have been enrolled.

Contact Information: Elizabeth Cunningham, Elizabeth.A.Cunningham@GSK.com.

NCT02964507

Funding: GSK

Citation Format: Pluard T, Oh SY, Oliveira M, Cescon D, Tan-Chiu E, Wu Y, Carpenter C, Cunningham E, Ballas M, Dhar A, Sparano J. A phase I/II dose escalation and expansion study to investigate the safety, pharmacokinetics, pharmacodynamics and clinical activity of GSK525762 in combination with fulvestrant in subjects with ER+ breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT3-06-07.

Abstract CT110: Ribociclib in combination with everolimus and exemestane in men and postmenopausal women with HR+/HER2− advanced breast cancer following progression on a CDK4/6 inhibitor: Safety, tolerability, and pharmacokinetic results from Phase 1 of TRINITI-1 study

Introduction: Preclinical data of improved antitumor activity upon addition of ribociclib to everolimus (EVE) and the interplay of CDK4/6 and the PI3K/mTOR pathway suggest a potential use for combination therapy to restore sensitivity to both CDK4/6 inhibition and endocrine therapy in patients whose disease progresses with CDK4/6 inhibitors. We present Phase 1 data of ribociclib (dosed continuously) + EVE + exemestane (EXE) in patients with endocrine-resistant ABC. Methods: TRINITI-1 is a Phase 1/2, open-label study of ribociclib (250 mg/d or 300 mg/d) + EVE 2.5 mg/d + EXE 25 mg/d in men and postmenopausal women with hormone receptor-positive, HER2− ABC who had progressed on 1 to 3 lines of systemic endocrine therapy, had measurable disease and/or lytic/mixed bone lesions, and had an Eastern Cooperative Oncology Group performance status score of ≤1 (NCT02732119). Progression on a CDK4/6 inhibitor was required only for patients in Phase 2. Patients with visceral crisis, unstable CNS metastases, progression after treatment with >1 CDK4/6 inhibitor, or clinically significant heart disease were excluded. The primary objective of Phase 1 was identification of the maximum tolerated dose (MTD) and/or the recommended Phase 2 dose (RP2D) of ribociclib + EVE + EXE. Secondary objectives included safety, tolerability, and pharmacokinetic analyses. Results: Among the 17 patients evaluated, 0 and 1 (11%) DLTs were noted in the ribociclib 250 mg/d and 300 mg/d cohorts, respectively (Grade 3 febrile neutropenia and Grade 4 neutropenia). Thus, MTD was not reached, and ribociclib 300 mg/d + EVE 2.5 mg/d + EXE 25 mg/d was declared the RP2D. Grade 3/4 drug-related AEs occurred in 75% of patients in each cohort; Grade 3/4 AEs (in >20% of patients) included neutropenia (25% and 50% in 250 mg and 300 mg cohorts, respectively) and decreased neutrophil count (38% and 0%). No increases in liver function tests or QTcF occurred. Median steady-state trough concentrations (Ctrough) of ribociclib at cycle 1, day 15, were 160 ng/mL and 210 ng/mL in the 250 mg/d and 300 mg/d cohorts, respectively, consistent with single-agent ribociclib 280 mg (164 ng/mL). However, median steady-state EVE Ctrough levels when combined with 250 mg and 300 mg ribociclib were within the therapeutic target of 5-15 ng/mL (7.8 ng/mL and 9.4 ng/mL, respectively) and were 2- to 3-fold greater than expected based on single-agent data.Conclusions: Ribociclib at 250 mg/d or 300 mg/d + EVE 2.5 mg/d + EXE 25 mg/d dosed continuously was safe in patients with HER2-, HR+ ABC. Ribociclib 300 mg/d was chosen for the RP2D and is being studied in Phase 2. Ribociclib Ctrough was similar to expected values, whereas EVE Ctrough was 2- to 3-fold greater than expected, resulting in EVE exposure within the therapeutic range despite the low EVE dose.

Citation Format: Sara Hurvitz, Denise Yardley, Amelia Zelnak, Angela DeMichele, Elizabeth Tan-Chiu, Cynthia Ma, Tania Small, Chris Tucci, Tanay Samant, Das Purkayastha, Stacy Moulder, Aditya Bardia. Ribociclib in combination with everolimus and exemestane in men and postmenopausal women with HR+/HER2− advanced breast cancer following progression on a CDK4/6 inhibitor: Safety, tolerability, and pharmacokinetic results from Phase 1 of TRINITI-1 study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr CT110. doi:10.1158/1538-7445.AM2017-CT110

A phase I/II dose escalation and expansion study to investigate the safety, pharmacokinetics, pharmacodynamics and clinical activity of GSK525762 in combination with fulvestrant in subjects with ER+ breast cancer

TPS1114

Background: Advanced or metastatic ER+BC (estrogen receptor positive breast cancer) is an incurable illness that will prove fatal for most afflicted women. Current standards of care include endocrine, targeted, and chemotherapy. Preclinical data suggest that reducing expression of the estrogen receptor (ER) as well as other ER-responsive genes may provide therapeutic benefit for women for whom endocrine therapy alone has proven inadequate. The bromodomain (BRD) and extra-terminal (BET) family of proteins (BRD2, BRD3, BRD4 and BRDT) bind to acetyl-histone residues and epigenetically control transcription of genes driving cell survival and proliferation. In preclinical models, BET proteins reduce ER expression and down regulate ER-dependent gene expression and may be a novel therapeutic target in multiple tumors e.g. ER+BC. GSK525762 is a pan-BET inhibitor showing strong synergistic activity with fulvestrant in killing ER+BC cells in vitro and in xenograft models. The combination of BET agents with endocrine therapy may provide therapeutic benefit and restore sensitivity to ER targeting agents like fulvestrant. Methods: The study is a Phase I/II dose-escalation, expansion (Phase I) and randomized control (Phase II) study with oral administration of GSK525762 in combination with fulvestrant in advanced or metastatic ER+BC subjects, whose disease has progressed on prior treatment with ≥ 1 line of endocrine therapy. Phase I of the study is designed as parallel single arms to determine the recommended Phase 2 dose based on safety, tolerability, PK, and efficacy profiles in two distinct populations of ER+ BC: 1. Subjects with disease that progressed on anti-estrogen and/or ≥ 1 AIs, OR. 2. Subjects with disease that progressed on CDK4/6 inhibitor plus letrozole. Phase I will employ a Bayesian predictive adaptive design. Phase II of the study is a randomized, double-blind, placebo-controlled study, the composition of which will be selected at the end of Phase I. Patients must have received < 3 lines of anti-cancer therapy (≤1 line of chemo), measurable disease, and PS 0-1. Funding: GSK. Clinical trial information: NCT02964507.

Abstract P4-22-22: Cobimetinib (C) combined with paclitaxel (P) as a first-line treatment in patients (pts) with advanced triple-negative breast cancer (COLET study): Updated clinical and biomarker results

Resistance to standard taxane-based chemotherapy is common in triple-negative breast cancer (TNBC). Mutations and gene amplifications in the MAPK pathway that upregulate MAPK signaling are present in many TNBC tumors. Upregulation of the MAPK signaling pathway can result in degradation of the pro-apoptotic protein BIM and upregulation of anti-apoptotic proteins, including BCL-2, BCL-XL, and MCL-1, thus promoting cell survival and desensitizing tumor cells to the pro-apoptotic effects of taxane chemotherapy. Updated data on clinical safety and efficacy are presented along with biomarker data evaluating the effects of treatment on induction of apoptosis.The COLET study (ClinicalTrials.gov ID, NCT02322814; EudraCT number, 2014-002230-32) consisted of a safety run-in (n∼12) followed by a blinded 1:1 randomized expansion stage (n∼90) to C + P or placebo (PBO) + P. The safety stage is complete and the randomized stage is enrolling pts. Two additional cohorts investigating the effect of adding atezolizumab will be recruiting and are out of scope of this submission. Pts in cohort I were treated with P 80 mg/m2 on days 1, 8, and 15 and C/PBO 60 mg/day on days 3–23 of each 28-day cycle until disease progression or unacceptable toxicity. Gene expression and apoptotic index were measured by RNA-Seq and TUNEL staining, respectively, to assess the biologic activity of C + P.Sixteen women (median age, 55.5 years) were enrolled in the safety run-in stage. At data snapshot (April 22, 2016), all 16 pts had received ≥1 dose of study treatment. Median time on treatment was 116 days (range, 7-336) for C and 84 days (range, 0-351) for P. Fifteen (94%) pts had ≥1 adverse event (AE); 5 (31%) pts had grade 1/2 AEs and 10 (63%) pts had grade 3 AEs (Table). No pts experienced grade 4–5 AEs. Among the 16 safety run-in patients, responses to date include partial response (PR; n = 8 [50.0%]), stable disease (SD, n = 4 [25.0%]), and progressive disease (n = 2 [12.5%]), as well as 2 pts with no post-baseline tumor assessment. Six pts maintained a PR at ∼20 weeks and three maintained a PR at ≥40 weeks. To date, matched pre- and on-treatment biopsies were evaluable for 2 pts, 1 with a PR and 1 with SD. In the patient who attained a PR, increased expression of pro-apoptosis genes, including BIM, was observed; but this was not seen in the patient experiencing SD. The PR patient also had an increase in apoptotic index. Updated biomarker data will be reported.This is the first study to evaluate C + P in TNBC. The safety profile of C + P is consistent with that of known safety profiles. Efficacy and safety will be further evaluated in the ongoing randomized stage.

Most common (any grade ≥20%) AEsTreatment-emergent AEs, n (%)C + P (safety run-in stage), N = 16 All gradesGrade 3Diarrhea10 (63)1 (6)Rash8 (50)0Nausea7 (44)0Alopecia5 (31)0Blood CPK level increase5 (31)1 (6)Stomatitis4 (25)2 (13)Asthenia4 (25)1 (6)Constipation4 (25)0Dyspnea4 (25)0Edema peripheral4 (25)0Pyrexia4 (25)0Vomiting4 (25)0AEs, adverse events; C, cobimetinib; CPK, creatinine phosphokinase; P, paclitaxel.

Citation Format: Brufsky A, Kim S-B, Velu T, García-Saenz JA, Tan-Chiu E, Sohn JH, Dirix L, Borms MV, Liu M-C, Moezi MM, Kozloff MF, Sparano JA, Xu N, Wongchenko M, Simmons B, McNally V, Miles D. Cobimetinib (C) combined with paclitaxel (P) as a first-line treatment in patients (pts) with advanced triple-negative breast cancer (COLET study): Updated clinical and biomarker results [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-22-22.

Abstract PD5-5: Phase 2 study of single agent MLN8237 (alisertib), an investigational aurora A kinase (AAK) inhibitor, in patients (pts) with relapsed/refractory breast cancer (BrC)

Background: AAK, a key mitotic regulator, is frequently amplified/overexpressed across a spectrum of tumors, including BrC. AAK overexpression is associated with poor prognosis. MLN8237 is an oral selective AAK inhibitor under evaluation in pts with advanced cancer as a single agent and in combination therapy. A phase 1/2 study (NCT01045421) evaluated MLN8237 in pts with different solid tumors; phase 2 data for the Brc cohort are presented.

Methods: Females aged ≥18 y with relapsed/refractory BrC including HR+, HER2+ and triple-negative histological subtype, ECOG PS 0–1, measurable disease by RECIST v1.1 and ≤4 prior cytotoxic chemotherapy regimens (not including adjuvant, neo-adjuvant; no limitation on prior hormonal or HER2 targeted, immunological or biological agents) were enrolled. Symptomatic brain metastases were excluded (treated stable metastasis allowed). A Simon's optimal 2-stage design was used; 20 pts were initially enrolled, expansion proceeded if ≥2 objective responses were observed in these response-evaluable pts. Pts received MLN8237 50 mg BID for 7 days in 21-day cycles. Primary objective: overall response rate (ORR). Secondary objectives: safety, duration of response (DOR) and progression-free survival (PFS). An exploratory study was performed to assess clinical responses in relation to candidate biomarker dysregulation (mutation, amplification, and deletion) in banked tumor specimens.

Results: As of April, 2013, 53 pts were enrolled: median age was 60 y (range 33–81), median of 4 cycles (range 1–21). 49 pts (92%) were response-evaluable (HR+, n = 26; HER2+, n = 9; triple negative, n = 14). 33% of pts received treatment for ≥6 months (HR+, n = 11 [69%]; HER2+, n = 3 [19%]; triple negative, n = 2 [12%]). ORR (all pts) was 18% and median PFS was 5.42 months. Efficacy data per subgroup are shown in the table. All 53 pts were included in the safety population; drug-related adverse events (AEs) were reported in 51 pts (96%), most frequent were neutropenia (55%), alopecia (49%) and diarrhea (45%). 38 pts (72%) had grade ≥3 drug-related AEs, including neutropenia (49%), leukopenia (21%) and febrile neutropenia (4%). G-CSF use was 32%. 2 pts (4%) discontinued due to AEs (sepsis [grade 4], n = 1; neutropenia [grade 3], n = 1); no on-study deaths were reported. Treatment is ongoing in 3 HR+ pts. Whole-exome sequencing of selected tumor samples was completed. Correlative analysis is ongoing to identify potential genetic markers/mutated pathways associated with clinical response. Preliminary results will be presented.

Conclusions: MLN8237 appears to have a generally manageable toxicity profile and shows signs of single agent antitumor activity in pts with heavily pretreated (different molecular subgroups) of relapsed/refractory BrC supporting further evaluation of MLN8237 in this tumor type in different combination strategies.

Efficacy HR+ (n = 26)HER2+ (n = 9)Triple-negative (n = 14)Best response,%ORR (PR)23227Stable disease653336Progressive disease124457Median DOR, months4.2-*-**Median PFS, months7.94.11.5*2 events, **1 event

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr PD5-5.

A phase 2 study of everolimus combined with trastuzumab and paclitaxel in patients with HER2-overexpressing advanced breast cancer that progressed during prior trastuzumab and taxane therapy

Increased activation of the PI3K/Akt/mTOR pathway is a common factor in putative mechanisms of trastuzumab resistance, resulting in dysregulation of cell migration, growth, proliferation, and survival. Data from preclinical and phase 1/2 clinical studies suggest that adding everolimus (an oral mTOR inhibitor) to trastuzumab plus chemotherapy may enhance the efficacy of, and restore sensitivity to, trastuzumab-based therapy. In this phase 2 multicenter study, adult patients with HER2-positive advanced breast cancer resistant to trastuzumab and pretreated with a taxane received everolimus 10 mg/day in combination with paclitaxel (80 mg/m² days 1, 8, and 15 every 4 weeks) and trastuzumab (4 mg/kg loading dose followed by 2 mg/kg weekly), administered in 28-day cycles. Endpoints included overall response rate (ORR), progression-free survival (PFS), overall survival (OS), and safety. Fifty-five patients were enrolled; one remained on study treatment at the time of data cutoff. The median number of prior chemotherapy lines for advanced disease was 3.5 (range 1–11). The ORR was 21.8 %, the clinical benefit rate was 36.4 %, the median PFS estimate was 5.5 months (95 % confidence interval [CI]: 4.99–7.69 months), and the median OS estimate was 18.1 months (95 % CI: 12.85–24.11 months). Hematologic grade 3/4 adverse events (AEs) included neutropenia (25.5 % grade 3, 3.6 % grade 4), anemia (7.3 % grade 3), and thrombocytopenia (5.5 % grade 3, 1.8 % grade 4). Nonhematologic grade 3/4 AEs included stomatitis (20.0 %), diarrhea (5.5 %), vomiting (5.5 %), fatigue (5.5 %), and pneumonia (5.5 %), all grade 3. These findings suggest that the combination of everolimus plus trastuzumab and paclitaxel is feasible, with promising activity in patients with highly resistant HER2-positive advanced breast cancer. This combination is currently under investigation in the BOLERO-1 phase 3 trial.

Seven-year follow-up assessment of cardiac function in NSABP B-31, a randomized trial comparing doxorubicin and cyclophosphamide followed by paclitaxel (ACP) with ACP plus trastuzumab as adjuvant therapy for patients with node-positive, human epidermal growth factor receptor 2-positive breast cancer

PURPOSE

Cardiac dysfunction (CD) is a recognized risk associated with the addition of trastuzumab to adjuvant chemotherapy for human epidermal growth factor receptor 2-positive breast cancer, especially when the treatment regimen includes anthracyclines. Given the demonstrated efficacy of trastuzumab, ongoing assessment of cardiac safety and identification of risk factors for CD are important for optimal patient care.

PATIENTS AND METHODS

In National Surgical Adjuvant Breast and Bowel Project B-31, a phase III adjuvant trial, 1,830 patients who met eligibility criteria for initiation of trastuzumab were evaluated for CD. Recovery from CD was also assessed. A statistical model was developed to estimate the risk of severe congestive heart failure (CHF). Baseline patient characteristics associated with anthracycline-related decline in cardiac function were also identified.

RESULTS

At 7-year follow-up, 37 (4.0%) of 944 patients who received trastuzumab experienced a cardiac event (CE) versus 10 (1.3%) of 743 patients in the control arm. One cardiac-related death has occurred in each arm of the protocol. A Cardiac Risk Score, calculated using patient age and baseline left ventricular ejection fraction (LVEF) by multiple-gated acquisition scan, statistically correlates with the risk of a CE. After stopping trastuzumab, the majority of patients who experienced CD recovered LVEF in the normal range, although some decline from baseline often persists. Only two CEs occurred more than 2 years after initiation of trastuzumab.

CONCLUSION

The late development of CHF after the addition of trastuzumab to paclitaxel after doxorubicin/ cyclophosphamide chemotherapy is uncommon. The risk versus benefit of trastuzumab as given in this regimen remains strongly in favor of trastuzumab.

Central nervous system metastases in patients with HER2-positive metastatic breast cancer: incidence, treatment, and survival in patients from registHER

PURPOSE

registHER is a prospective, observational study of 1,023 newly diagnosed HER2-positive metastatic breast cancer (MBC) patients.

EXPERIMENTAL DESIGN

Baseline characteristics of patients with and without central nervous system (CNS) metastases were compared; incidence, time to development, treatment, and survival after CNS metastases were assessed. Associations between treatment after CNS metastases and survival were evaluated.

RESULTS

Of the 1,012 patients who had confirmed HER2-positive tumors, 377 (37.3%) had CNS metastases. Compared with patients with no CNS metastases, those with CNS metastases were younger and more likely to have hormone receptor-negative disease and higher disease burden. Median time to CNS progression among patients without CNS disease at initial MBC diagnosis (n = 302) was 13.3 months. Treatment with trastuzumab, chemotherapy, or surgery after CNS diagnosis was each associated with a statistically significant improvement in median overall survival (OS) following diagnosis of CNS disease (unadjusted analysis: trastuzumab vs. no trastuzumab, 17.5 vs. 3.8 months; chemotherapy vs. no chemotherapy, 16.4 vs. 3.7 months; and surgery vs. no surgery, 20.3 vs. 11.3 months). Although treatment with radiotherapy seemed to prolong median OS (13.9 vs. 8.4 months), the difference was not significant (P = 0.134). Results of multivariable proportional hazards analyses confirmed the independent significant effects of trastuzumab and chemotherapy (HR = 0.33, P < 0.001; HR = 0.64, P = 0.002, respectively). The effects of surgery and radiotherapy did not reach statistical significance (P = 0.062 and P = 0.898, respectively).

CONCLUSIONS

For patients with HER2-positive MBC evaluated in registHER, the use of trastuzumab, chemotherapy, and surgery following CNS metastases were each associated with longer survival.

Phase II study of the antibody drug conjugate trastuzumab-DM1 for the treatment of human epidermal growth factor receptor 2 (HER2)-positive breast cancer after prior HER2-directed therapy

PURPOSE

The antibody-drug conjugate trastuzumab-DM1 (T-DM1) combines the biologic activity of trastuzumab with targeted delivery of a potent antimicrotubule agent, DM1, to human epidermal growth factor receptor 2 (HER2)-overexpressing cancer cells. Based on results from a phase I study that showed T-DM1 was well tolerated at the maximum-tolerated dose of 3.6 mg/kg every 3 weeks, with evidence of efficacy, in patients with HER2-positive metastatic breast cancer (MBC) who were previously treated with trastuzumab, we conducted a phase II study to further define the safety and efficacy of T-DM1 in this patient population.

PATIENTS AND METHODS

This report describes a single-arm phase II study (TDM4258g) that assessed efficacy and safety of intravenous T-DM1 (3.6 mg/kg every 3 weeks) in patients with HER2-positive MBC who had tumor progression after prior treatment with HER2-directed therapy and who had received prior chemotherapy.

RESULTS

With a follow-up of ≥ 12 months among 112 treated patients, the objective response rate by independent assessment was 25.9% (95% CI, 18.4% to 34.4%). Median duration of response was not reached as a result of insufficient events (lower limit of 95% CI, 6.2 months), and median progression-free survival time was 4.6 months (95% CI, 3.9 to 8.6 months). The response rates were higher among patients with confirmed HER2-positive tumors (immunohistochemistry 3+ or fluorescent in situ hybridization positive) by retrospective central testing (n = 74). Higher response rates were also observed in patients whose tumors expressed ≥ median HER2 levels by quantitative reverse transcriptase polymerase chain reaction for HER2 expression, compared with patients who had less than median HER2 levels. T-DM1 was well tolerated with no dose-limiting cardiotoxicity. Most adverse events (AEs) were grade 1 or 2; the most frequent grade ≥ 3 AEs were hypokalemia (8.9%), thrombocytopenia (8.0%), and fatigue (4.5%).

CONCLUSION

T-DM1 has robust single-agent activity in patients with heavily pretreated, HER2-positive MBC and is well tolerated at the recommended phase II dose.

registHER: Treatment outcomes in patients with HER2-positive (HER2+), hormone receptor-positive (HR+) metastatic breast cancer (MBC)

1057

Background: Approximately 50% of HER2+ breast cancers are HR+ (defined as estrogen receptor [ER] and/or progesterone receptor [PR] positive). Cross talk between growth factor and ER-dependent signaling pathways may affect growth regulation in HER2+ breast cancers. Blockade of both pathways appears to be more active than blocking either alone based on randomized trials performed in selected populations. However, the outcomes of HER2+ and HR+ MBC patients relative to those in real- life clinical practice have not been evaluated in large cohort studies. Methods: registHER is a prospective observational study of 1023 patients with newly diagnosed (within 6 months [mo]) HER2+ MBC treated in community/academic settings, enrolled from 12/03 to 2/06. Median follow-up from MBC diagnosis was 25 mo at data cutoff (1/02/08). Treatment patterns and outcomes in patients with HER2+/HR+ MBC receiving 1st-line therapy (i.e., therapies received prior to 1st progression) are described in this analysis. Results: Of the 963 (94%) treated HER2+ patients with recorded HR tumor status, 55% (533) were HR+ and 45% (430) were HR-negative. 1st-line MBC treatment regimens for HER2+/HR+ patients included endocrine therapy (E) only, 57 (10.7%); E + trastuzumab (T), 50 (9.4%); chemotherapy (C) ± E, 41 (7.7%); and C + trastuzumab (T) ± E, 361 (67.7%). Progression-free survival (PFS) and overall survival (OS) by 1st line treatment groups are in the table. Conclusions: In registHER, HER2+/HR+ patients treated with E+T had longer PFS than patients treated with E alone; E- alone median PFS is consistent with findings in prospective randomized trials. These data provide further information regarding trastuzumab's role in targeting dual pathways in HER2+/HR+ MBC patients in a real-world setting. Multivariate analysis to address potential bias from known prognostic factors that may influence treatment choice will be presented.

[Table: see text]

[Table: see text]

Phase II study of eribulin mesylate, a halichondrin B analog, in patients with metastatic breast cancer previously treated with an anthracycline and a taxane

PURPOSE

Eribulin mesylate (E7389), a nontaxane microtubule dynamics inhibitor, is a structurally simplified, synthetic analog of the marine natural product halichondrin B. This open-label, single-arm, phase II study evaluated efficacy and tolerability of eribulin in heavily pretreated patients with metastatic breast cancer (MBC).

METHODS

MBC patients who were previously treated with an anthracycline and a taxane received eribulin mesylate (1.4 mg/m(2)) as a 2- to 5-minute intravenous (IV) infusion on days 1, 8, and 15 of a 28-day cycle. Because of neutropenia (at day 15), an alternative regimen of eribulin on days 1 and 8 of a 21-day cycle was administered. The primary end point was overall response rate.

RESULTS

Of the 103 patients treated, the median number of prior chemotherapy regimens was four (range, one to 11 regimens). In the per-protocol population (n = 87), eribulin achieved an independently reviewed objective response rate (all partial responses [PRs]) of 11.5% (95% CI, 5.7 to 20.1) and a clinical benefit rate (PR plus stable disease > or = 6 months) of 17.2% (95% CI, 10.0 to 26.8). The median duration of response was 171 days (5.6 months; range, 44 to 363 days), the median progression-free survival was 79 days (2.6 months; range, 1 to 453 days), and the median overall survival was 275 days (9.0 months; range, 15 to 826 days). The most common drug-related grades 3 to 4 toxicities were as follows: neutropenia, 64%; leukopenia, 18%; fatigue, 5%; peripheral neuropathy, 5%; and febrile neutropenia, 4%.

CONCLUSION

Eribulin demonstrated activity with manageable tolerability (including infrequent grade 3 and no grade 4 neuropathy) in heavily pretreated patients with MBC when dosed as a short IV infusion on days 1 and 8 of a 21-day cycle.

Single-agent lapatinib for HER2-overexpressing advanced or metastatic breast cancer that progressed on first- or second-line trastuzumab-containing regimens

BACKGROUND

This phase II study evaluated the efficacy and safety of lapatinib in patients with human epidermal growth factor receptor 2 (HER2)-positive advanced or metastatic breast cancer that progressed during prior trastuzumab therapy.

PATIENTS AND METHODS

Women with stage IIIB/IV HER2-overexpressing breast cancer were treated with single-agent lapatinib 1250 or 1500 mg once daily after protocol amendment. Tumor response according to RECIST was assessed every 8 weeks. HER2 expression was assessed in tumor tissue by immunohistochemistry and FISH.

RESULTS

Seventy-eight patients were enrolled in the study. Investigator and independent review response rates [complete response (CR) or partial response (PR)] were 7.7% and 5.1%, and clinical benefit rates (CR, PR, or stable disease for >or=24 weeks) were 14.1% and 9.0%, respectively. Median time to progression was 15.3 weeks by independent review, and median overall survival was 79 weeks. The most common treatment-related adverse events were rash (47%), diarrhea (46%), nausea (31%), and fatigue (18%).

CONCLUSIONS

Single-agent lapatinib has clinical activity with manageable toxic effects in HER2-overexpressing breast cancer that progressed on trastuzumab-containing therapy. Studies of lapatinib-based combination regimens with chemotherapy and other targeted therapies in metastatic and earlier stages of breast cancer are warranted.

A multi-center phase II study of three doses of TAS-108 in postmenopausal women with advanced breast carcinoma following first or second line endocrine therapy

Abstract #2131

Introduction: TAS-108 is an oral steroidal anti-estrogen agent that selectively inhibits ERα and is mainly metabolized by CYP3A4. The purpose of this study is to investigate the efficacy and safety of TAS-108 administrated orally in three dose levels in patients with locally advanced, locally recurrent inoperable or metastatic breast carcinoma (BC) in four countries (USA, Russia, Mexico and Chile).&#x2028; Methods: Postmenopausal women with confirmed ER and/or PgR positive BC who had previously responded to one or two standard endocrine therapies, with or without one prior chemotherapy were randomly assigned to three doses of TAS-108, 40 mg, 80 and 120 mg daily. Using a modified Panageas' optimal two-stage trinomial design, the enrollment of 60 evaluable patients (first-stage: 19) was required to each individual dose group. Tumor response was assessed every 8 weeks according to RECIST criteria. Adverse events (AEs) were graded by CTC-AE v3.0.&#x2028; Results: A total of 146 patients with mean age of 63 years old were enrolled with 61 patients in the 40 mg group and 66 in the 80 mg group. The 120 mg group was terminated at the end of stage 1 with 19 patients enrolled due to lack of efficacy. The mean duration of study treatment was 172 days for the 40 mg group and 160 days for the 80 mg group. Partial response (PR) was documented in 6 (10%) patients in the 40 mg group and 4 (6.7%) patients in the 80 mg group. The rate of disease stabilization (CR+PR+SD) reported by the investigators was 43% (95%CI, 31%,56%) in the 40 mg group and 45% (95%CI, 32%,58%) in the 80 mg group. Adjudicated clinical benefit (CR+PR+SD more than 24 wks) was observed in 22% of patients in the 40 mg group and 20% of patients in the 80 mg group. Clinical benefit was achieved in 25% of patients with 1 prior hormonal therapy and 15% of patients with more than one line of prior hormonal therapy. Median time to progression (TTP): 15 weeks for the 40 mg group and 15.9 weeks for the 80 mg group. Median duration of clinical benefit was 32 weeks in the 40 mg group and 64 weeks in the 80 mg group. In the 40/80/120 mg groups, the commonly reported treatment-related AEs included nausea (15%/11%/16%), fatigue (10%/11%/16%), headache (10%/6%/16%), hot flushes (10%/5%/32%), diarrhea (2%/6%/5%), constipation (3%/3%/5%), and arthralgia (2%/5%/11%). No endometrial cancer and treatment-related deaths occurred during the study.&#x2028; Conclusions: TAS-108 has demonstrated anti-tumor activity in this population and was generally well tolerated. The 40 mg dose was chosen as the recommended dose for future clinical evaluation in patients with advanced breast cancer.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2131.

Survival of patients with HER2+ metastatic breast cancer and use of trastuzumab following progression: analysis of RegistHER

Abstract #3142

Background: Most HER2+ metastatic breast cancer (MBC) patients who initially respond to trastuzumab (T)-based therapies will experience disease progression (PD). Standard practice is to discontinue the cytotoxic agent on which disease progressed, however there is evidence that tumors may remain sensitive to HER2 targeting and that there may be a potentiating effect of T on chemotherapy. We examined the treatment history of a large population of HER2+ MBC patients to assess outcomes associated with continuation of T beyond PD.&#x2028; Methods: This analysis was carried out on patients enrolled in registHER, a prospective observational study of 1023 patients with newly diagnosed (within 6 months) HER2+ MBC. Median f/u from MBC diagnosis is 25 months at the time of data cut-off (12/31/07). For those treated with T prior to first PD, we compared demographics and baseline tumor characteristics for those patients treated with or without T following first PD. Treatment with T was defined as a minimum of 21 days of therapy prior to PD. In addition, we evaluated time to second PD, and overall survival post PD (both endpoints calculated from initial PD). Overall survival (OS) was also calculated from the date of treatment initiation to death for the entire treated cohort.&#x2028; Results: Of 1023 evaluable patients, 873 (85%) were treated with any T-based first-line therapy. 622 T-treated patients progressed and 500 were subsequently treated with T following first PD. Patients who received T post first PD tended to be younger (&lt;50 years of age, 45.2% vs 29.5%) and have hormone receptor positive disease (51.4% vs 42.0%) compared with patients who did not receive T post first PD. Among all treated patients the median overall survival was 35.6 mo (25th-75th-ile:18.6-63.1 mo). Median survival post PD in the 500 patients treated with trastuzumab following first PD was 21.2 mo (25th-75th-ile:11.8-35.8mo).&#x2028; Conclusions: OS in patients on the prospective observational study registHER is longer than the OS of 25.1 months noted in the pivotal trial of first-line HER2+ MBC patients treated with T plus chemotherapy. We will present data on the association between various pre- and post-treatment factors, including the use of T beyond PD, and PFS and OS. This will include a multivariate analysis that specifically examines the association between T use in later lines and survival.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3142.

registHER: Patient characteristics, treatment patterns, and preliminary outcomes in patients with HER2-positive (HER2+), hormone receptor-positive (HR+) metastatic breast cancer (MBC)

21007

Background: Approximately 50% of HER2+ breast cancers are HR+, however, the interaction between HER2 and HR is not completely understood. Patients with HR+/HER2+ or HR-/HER2+ tumors treated with trastuzumab + chemotherapy (CT) achieve similar clinical benefit. Retrospective analyses suggest that HER2+ tumors are resistant to hormone therapy (HT), particularly anti-estrogens, possibly due to estrogen receptor /HER2 interactions and quantitatively lower HR expression in HER2+/HR+ tumors. Conducting randomized clinical trials in HER2+/HR+ MBC is challenging given the small patient population. Methods: registHER is a prospective observational study of approximately 1000 patients with newly diagnosed (<6 months) HER2+ MBC treated in community or academic settings. Baseline characteristics and treatment patterns in patients with HR+ vs HR-, HER2+ MBC receiving first-line therapy were studied in this analysis. The influence of adjuvant HT on disease-free intervals (DFI) from time of diagnosis and MBC treatment selection in patients with HR+/HER2+ tumors was examined. Results: Of 976 patients with HER2+ MBC and recorded tumor HR status, those with HR+ MBC (54.9%) tended to be white (81.7% vs 77.0%), were more likely to have bone only metastases (18.1% vs 6.4%), less likely to have CNS metastases (2.8% vs 8.2%), and have fewer metastatic sites at diagnosis (49.1% vs 43.2%) than those with HR- MBC. Of patients with HR+ MBC, who were stage I- III at initial diagnosis, 51.3% received adjuvant HT, of which 73.2% received tamoxifen. Median DFI was 48.8 vs 29.4 mo for patients receiving tamoxifen vs an aromatase inhibitor. First-line MBC treatment regimens included: HT only (13.8%); HT + trastuzumab (8.4%); HT + trastuzumab + CT (6.2%); trastuzumab only (6.0%); CT only (11.0%); trastuzumab + CT (53.5%). Analyses of progression-free survival by HR status and first-line treatments (HT only, trastuzumab ± HT or ± CT), are ongoing and will be described. Conclusions: registHER represents the largest dataset of patients with HER2+/HR+ MBC and provides a unique opportunity to characterize treatment patterns, efficacy and safety, and the natural history of this subset of breast cancer patients.

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Zoledronic Acid Inhibits Adjuvant Letrozole–Induced Bone Loss in Postmenopausal Women With Early Breast Cancer

Purpose

Treatment with aromatase inhibitors decreases bone mineral density (BMD) and may increase the risk of fractures in postmenopausal women with early-stage breast cancer. The addition of zoledronic acid to adjuvant letrozole therapy may protect against bone loss.

Patients and Methods

Patients receiving adjuvant letrozole were randomly assigned to receive either upfront or delayed-start zoledronic acid (4 mg intravenously every 6 months). The delayed group received zoledronic acid when lumbar spine (LS) or total hip (TH) T score decreased to less than −2.0 or when a nontraumatic fracture occurred. The primary end point of this study was to compare the change in LS BMD at month 12 between the groups. Secondary end points included change in TH BMD and changes in serum bone turnover markers at month 12.

Results

The upfront and delayed groups each included 301 patients. At month 12, LS BMD was 4.4% higher in the upfront group than in the delayed group (95% CI, 3.7% to 5.0%; P < .0001), and TH BMD was 3.3% higher (95% CI, 2.8% to 3.8%; P < .0001). In the upfront group, mean serum N-telopeptide and bone-specific alkaline phosphatase concentrations decreased by 15.1% (P < .0001) and 8.8% (P = .0006), respectively, at month 12, whereas concentrations increased significantly in the delayed group by 19.9% (P = .013) and 24.3% (P < .0001), respectively.

Conclusion

With 1 year of follow-up, results of the primary end point of the Zometa-Femara Adjuvant Synergy Trial (Z-FAST) indicate that upfront zoledronic acid therapy prevents bone loss in the LS in postmenopausal women receiving adjuvant letrozole for early-stage breast cancer.

Updated results of a multicenter phase II trial of neoadjuvant docetaxel, carboplatin and capecitabine for inflammatory and locally advanced breast cancer (LABC)

10685

Background: Neoadjuvant chemotherapy for the treatment of LABC has become the standard of care but the best combination is not established. The combination of docetaxel and capecitabine demonstrates synergism in patients(pts) with metastatic breast cancer (MBC). Recent studies support the value of platinum salts in LABC and MBC. Methods: pts with stage IIA-IIIC or inflammatory BC, EGOG PS 0–1, are eligible.We are evaluating the combination of weekly docetaxel 30mg/m2, carboplatin AUC2 on D1, 8,15 of a 4-week cycle plus capecitabine 625 mg/m2 BID given on days 5–18 (based on the upregulation of thymidine phosphorylase) for 4 cycles prior to surgery. The primary objective of this phase II trial is pCR rate in breast. Results: 39 of 48 pts have been enrolled from 7 centers. Median age 46 (range 26–75), stage II 41%, stage III 59%. Median baseline tumor is 5.4cm (range 2.1–15); 1pt inflammatory BC; 10 pts N2 disease (36%); 12 tumors were ER+, 20 ER-, and 5 Her-2+. To date, 2,377 doses (including daily capecitabine doses) were administered out of a total of 2,560 (93% of intended doses) with only 10 dose delays and 8 dose reductions. 37 pts are evaluable for toxicities. No grade IV toxicities were seen, grade III neutropenia was seen in 3/37(8%) and grade III fatigue in 1/37(3%). There were no episodes of neutropenic fever.The most common grade I/II toxicities were nausea in 57%, diarrhea 38%, fatigue 43%, epiphora 24%, mucositis 24% and hand-foot syndrome 3%. No death related treatments have been reported. 32 pts have completed definitive surgery. Objective clinical response is 94% with 53% cCR. 5 patients had pCRs in breast(16%) and 5 pCR in breast and axilla(16%). 9 pts (28%) have microscopic residual disease in the breast (<3mm). 14 pts had complete axillary clearance (44%). Conclusions: The preoperative combination of docetaxel, carboplatin and capecitabine is feasible with very good response rate and a very acceptable toxicity profile. Accrual is ongoing.

No significant financial relationships to disclose.

Phase II study of gemcitabine (Gem) and trastuzumab (T) combination therapy in first line metastatic breast cancer (MBC) patients (pts) with HER2 overexpression

10591

Background: Phase III studies have demonstrated that the addition of T to chemo is associated with higher response rates (RR), improved time-to-progression (TTP) and improved overall survival in pts with metastatic HER2+ tumors. The greatest benefit from T-based therapy is found in women with pronounced HER2 overexpression (FISH+ or IHC 3+). Preclinical models suggest that Gem+T appear to be additive or synergistic. The present study was designed to determine overall RR (primary endpoint), TTP, OS and the toxicity profile of the combination of Gem+T as first-line therapy for MBC pts. Methods: Pts with measurable HER2-overexpressing (IHC 3+ or FISH+) MBC, no prior chemo in the metastatic setting (adjuvant was allowed), adequate end-organ function and PS 0–2, received Gem 1,250 mg/m2 on days 1 and 8 and T on day 1 (8 mg/kg over 90 min on cycle 1, then 6 mg/kg over 30 min on subsequent cycles) of a 21-day cycle, until progressive disease or undue toxicity. A Simon’s optimal two-stage design was used with a total sample size of 66 (25 patients treated in the first stage and 41 additional patients in the second stage). Results: Sixty-six patients have been treated and results are available for sixty-four patients. Median age: 53 years (range 34–83); Race: Caucasian/Other 88%/12%. ER status positive/negative: 53%/47%. HER2 status IHC 3+/FISH+: 58/20 pts.; ECOG PS 0/1/2: 66%/30%/3%; Prior adjuvant therapy: Chemo 39 pts (prior anthra 31, prior taxane 21), Hormonal 32 pts (6 adj, 18 met, 8 both). Total number of cycles = 396; median = 6 (range 1–21). Toxicity was generally modest. Grade 3/4 neutropenia occurred in 11 pts (17%)/7 pts (11%); thrombocytopenia 3pts (5%)/1pt (2%), anemia 3 pts (4.7%)/ 0 pts, and 2 pts with grade 4 transaminase elevation, grade 3 elevated ALT 6 pts (9.4%); no other grade 4 toxicities were recorded. One pt with prior anthra exposure had a grade 2 decrease in left ventricular ejection fraction; no symptomatic cardiac toxicity was recorded. Best Overall RR assessment (N = 64): CR 8 (12.5%), PR 26 (40.6%) for an overall RR of 53.1% (95% CI: 40%-66%). TTP median 6 mo (95% CI: 4.4 -9.7 mo). Survival data not mature at this time. Conclusions: The combination of Gem+T in front-line MBC shows a high response rate with modest toxicity.

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Capecitabine plus docetaxel (XT): A first line, phase II clinical trial in metastatic breast cancer

10624

Background: The XT combination originally published at (X) dosed at 1250 mg/m2 bid po x 14 days and (T) at 75 mg/m2 q3 weeks I.V. respectively yielded good response rates and an overall survival advantage compared with single agent docetaxel at 100 mg/m2. However, the toxicity profile of this regimen has led to major dose and schedule modifications by most oncologists. Methods/Results: We initiated a Phase II trial at doses of X at 900 mg/m2 bid po x 14 days and T at 36 mg/m2 d 1 and 8. Three responded and the mean no. of cycles for these patients was 3.8. Since four of 6 went off study because of toxicity two additional dose levels were studied in 6 patients each. A second cohort received X at 650 mg/m2 bid and T at 30 mg/m2. With 6 evaluable patients, four of 6 responded but all 4 required further dose reductions. Mean no. of cycles received was 4.2. A third cohort of 6 patients received X at 825 mg/m2 plus the lower T at 30mg/m2 who received a mean no. of cycles of 6. While only 1/6 responded 3 additional patients had stable disease with marked decreases in CEA or CA 15–3 suggestive of anti-tumor response. Only 1/6 required a dose reduction. Among the 18 patients, epiphora was described by 5 (28%). Only 3 patients developed significant leukopenia, and thrombocytopenia was not seen. T-induced nail changes were uncommon but were severe in one patient. Two patients at the first dose level, but only one at lower levels developed mucositis. Grade 1 anemia was common but managed easily with growth factor support. Conclusions: The response rate of 44% is encouraging with these lower doses of XT. We recommend further studies using X at 825 mg/m2 and T at 30mg/m2 since these doses were associated with encouraging response rate and a better toxicity profile than higher doses. Even at this higher dose of X dose reductions may well be needed. (Supported by a grant from Roche Laboratories, Inc.)

No significant financial relationships to disclose.

registHER: Baseline characteristics of a cohort of HER2-positive metastatic breast cancer (MBC) patients

20095

Background: HER2 is amplified in 25% of breast cancers and is associated with poor survival. registHER captures the natural history, treatment patterns and outcomes in 1000 newly-diagnosed HER2-positive MBC patients (pts) throughout the U.S. This observational study recruits pts in both academic and community centers. Methods: This ongoing prospective cohort study collects clinical, pathologic and treatment data at enrollment, quarterly until death, loss to follow-up or 3 years after the last enrollment. We describe baseline pt and clinical characteristics in registHER compared with HER2-positive MBC pts in the phase III pivotal trial (Slamon DJ, et al. N Engl J Med. 2001;344:783–792). Results: Between December 2003 and September 2005, 813 eligible pts were enrolled at 280 study sites. Most pts were seen at community-based (76%) vs academic (18%) clinics; a few pts did not fall into either category (6%). A comparison of baseline characteristics is shown below. Conclusions: registHER pts tended to have a shorter disease-free interval and more estrogen receptor positive disease than pts in the pivotal trial. Reasons for these differences could reflect trial referral and/or diagnostic testing differences. Fewer registHER patients were white, but other characteristics were similar between the two groups. These findings support the hypothesis that observational studies describe a broad patient population which may not exactly duplicate clinical trials. Within registHER, there was some variation between academic vs community clinics (eg. nodal status and adjuvant therapy). Treatment pattern analyses are ongoing.

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Evaluation of a recombinant HER2 vaccine: Induction of specific antibodies, T-cells and preliminary activity in metastatic breast cancer patients

631

Background: We designed a vaccine to induce T cells able to recognize epitopes from HER2 and to engender a polyclonal antibody reponse. Methods: The vaccine is a recombinant HER2 protein, including its extra and part of its intra-cellular domains (ECD/ICD), combined with a potent immunologic adjuvant. Cohorts of patients with Stage II/III breast cancer (BC) received 20, 100 or 500 μg in the adjuvant setting. Treatment comprised of six vaccinations over 14 weeks, for the 500-μg dose, recall injections were given on weeks 34 and 38. The trial was extended to include an alternative vaccination schedule: 500 μg on days 0, 28 and 98. In an on-going trial, patients with metastatic BC treated in the first line setting are receiving the 500-μg treatment and being assessed for clinical response. Results: The vaccine was well tolerated, with no symptomatic cardiotoxicity. Antibody (Ab) response against ECD was dose-dependent, with 2/12, 9/14 and 14/15 immune responders in the respective cohorts after four vaccinations. Response was dose-related. Ab isotypes were analyzed in the 500 μg cohort: in 50% of patients, high levels of IgM (30–60%) against ECD were found after four vaccinations. The switch towards IgG was complete in all patients after six vaccinations. The efficacy of booster vaccinations was observed mainly in patients with low IgM after eight weeks. After two vaccinations, Ab titers on the alternative 500 μg vaccination schedule were as high as after four vaccinations utilizing the initial schedule. The anti-ECD antibodies in 11/15 patients (500 μg level) bound HER2-overexpressing breast-cancer cell lines. In sera from 2 patients tested thus far, the gene-expression resembled that of trastuzumab. Assays show that specific T cells were obtained; detailed analysis is continuing. Among metastatic patients, two showed evidence of tumor regression after vaccination. Conclusions: The HER2 vaccine was well tolerated and induced (dose-dependently) anti-ECD Ab that bound the HER2 receptor. Data suggest that the vaccine also induced specific T-cell immunity. The alternative vaccination schedule may increase the Ab titers. This data justifies further evaluation of this vaccine in the phase II/III setting.

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Prognosis after ipsilateral breast tumor recurrence and locoregional recurrences in five National Surgical Adjuvant Breast and Bowel Project node-positive adjuvant breast cancer trials

PURPOSE

Locoregional failure after breast-conserving surgery is associated with increased risk of distant disease and death. The magnitude of this risk in patients receiving chemotherapy has not been adequately characterized.

PATIENTS AND METHODS

Our study population included 2,669 women randomly assigned onto five National Surgical Adjuvant Breast and Bowel Project node-positive protocols (B-15, B-16, B-18, B-22, and B-25), who were treated with lumpectomy, whole-breast irradiation, and adjuvant systemic therapy. Cumulative incidences of ipsilateral breast tumor recurrence (IBTR) and other locoregional recurrence (oLRR) were calculated. Kaplan-Meier curves were used to estimate distant-disease-free survival (DDFS) and overall survival (OS) after IBTR or oLRR. Cox models were used to model survival using clinical and pathologic factors jointly with IBTR or oLRR as time-varying predictors.

RESULTS

Four hundred twenty-four patients (15.9%) experienced locoregional failure; 259 (9.7%) experienced IBTR, and 165 (6.2%) experienced oLRR. The 10-year cumulative incidence of IBTR and oLRR was 8.7% and 6.0%, respectively. Most locoregional failures occurred within 5 years (62.2% for IBTR and 80.6% for oLRR). Age, tumor size, and estrogen receptor status were significantly associated with IBTR. Nodal status and estrogen and progesterone receptor status were significantly associated with oLRR. The 5-year DDFS rates after IBTR and oLRR were 51.4% and 18.8%, respectively. The 5-year OS rates after IBTR and oLRR were 59.9% and 24.1%, respectively. Hazard ratios for mortality associated with IBTR and oLRR were 2.58 (95% CI, 2.11 to 3.15) and 5.85 (95% CI, 4.80 to 7.13), respectively.

CONCLUSION

Node-positive breast cancer patients who developed IBTR or oLRR had significantly poorer prognoses than patients who did not experience these events.

Assessment of cardiac dysfunction in a randomized trial comparing doxorubicin and cyclophosphamide followed by paclitaxel, with or without trastuzumab as adjuvant therapy in node-positive, human epidermal growth factor receptor 2-overexpressing breast cancer: NSABP B-31

PURPOSE

Trastuzumab is effective in treating human epidermal growth factor receptor 2 (HER2) -positive breast cancer, but it increases frequency of cardiac dysfunction (CD) when used with or after anthracyclines.

PATIENTS AND METHODS

National Surgical Adjuvant Breast and Bowel Project trial B-31 compared doxorubicin and cyclophosphamide (AC) followed by paclitaxel with AC followed by paclitaxel plus 52 weeks of trastuzumab beginning concurrently with paclitaxel in patients with node-positive, HER2-positive breast cancer. Initiation of trastuzumab required normal post-AC left ventricular ejection fraction (LVEF) on multiple-gated acquisition scan. If symptoms suggestive of congestive heart failure (CHF) developed, source documents were blindly reviewed by an independent panel of cardiologists to determine whether criteria were met for a cardiac event (CE), which was defined as New York Heart Association class III or IV CHF or possible/probable cardiac death. Frequencies of CEs were compared between arms.

RESULTS

Among patients with normal post-AC LVEF who began post-AC treatment, five of 814 control patients subsequently had confirmed CEs (four CHFs and one cardiac death) compared with 31 of 850 trastuzumab-treated patients (31 CHFs and no cardiac deaths). The difference in cumulative incidence at 3 years was 3.3% (4.1% for trastuzumab-treated patients minus 0.8% for control patients; 95% CI, 1.7% to 4.9%). Twenty-seven of the 31 patients in the trastuzumab arm have been followed for > or = 6 months after diagnosis of a CE; 26 were asymptomatic at last assessment, and 18 remained on cardiac medication. CHFs were more frequent in older patients and patients with marginal post-AC LVEF. Fourteen percent of patients discontinued trastuzumab because of asymptomatic decreases in LVEF; 4% discontinued trastuzumab because of symptomatic cardiotoxicity.

CONCLUSION

Administering trastuzumab with paclitaxel after AC increases incidence of CHF and lesser CD. Potential cardiotoxicity should be carefully considered when discussing benefits and risks of this therapy.

Trastuzumab plus adjuvant chemotherapy for operable HER2-positive breast cancer

BACKGROUND

We present the combined results of two trials that compared adjuvant chemotherapy with or without concurrent trastuzumab in women with surgically removed HER2-positive breast cancer.

METHODS

The National Surgical Adjuvant Breast and Bowel Project trial B-31 compared doxorubicin and cyclophosphamide followed by paclitaxel every 3 weeks (group 1) with the same regimen plus 52 weeks of trastuzumab beginning with the first dose of paclitaxel (group 2). The North Central Cancer Treatment Group trial N9831 compared three regimens: doxorubicin and cyclophosphamide followed by weekly paclitaxel (group A), the same regimen followed by 52 weeks of trastuzumab after paclitaxel (group B), and the same regimen plus 52 weeks of trastuzumab initiated concomitantly with paclitaxel (group C). The studies were amended to include a joint analysis comparing groups 1 and A (the control group) with groups 2 and C (the trastuzumab group). Group B was excluded because trastuzumab was not given concurrently with paclitaxel.

RESULTS

By March 15, 2005, 394 events (recurrent, second primary cancer, or death before recurrence) had been reported, triggering the first scheduled interim analysis. Of these, 133 were in the trastuzumab group and 261 in the control group (hazard ratio, 0.48; P<0.0001). This result crossed the early stopping boundary. The absolute difference in disease-free survival between the trastuzumab group and the control group was 12 percent at three years. Trastuzumab therapy was associated with a 33 percent reduction in the risk of death (P=0.015). The three-year cumulative incidence of class III or IV congestive heart failure or death from cardiac causes in the trastuzumab group was 4.1 percent in trial B-31 and 2.9 percent in trial N9831.

CONCLUSIONS

Trastuzumab combined with paclitaxel after doxorubicin and cyclophosphamide improves outcomes among women with surgically removed HER2-positive breast cancer. (ClinicalTrials.gov numbers, NCT00004067 and NCT00005970.)

Response to fulvestrant in heavily pretreated postmenopausal women:a single-center experience

Fulvestrant ('Faslodex') is a new estrogen receptor (ER) antagonist that has no agonist effects. It binds, blocks and accelerates degradation of the ER, leading to a complete abrogation of estrogen-sensitive gene transcription. In postmenopausal women with advanced breast cancer progressing on prior endocrine therapy, fulvestrant is at least as effective as the third-generation aromatase inhibitor (AI) anastrozole. In this single-center experience, 42 postmenopausal patients with metastatic breast cancer who had been heavily pretreated with prior endocrine therapy and chemotherapy were treated with fulvestrant. Prior endocrine therapies included selective ER modulators (including tamoxifen and toremifene), AIs, megestrol acetate, and high-dose estrogens. In total, eight patients (19%) achieved stable disease (SD) for > or =24 weeks, including two patients with SD for 2 years and one with SD for 14 months. Fulvestrant was well tolerated with the majority of adverse events related to the site of metastatic disease. These data demonstrate that fulvestrant is a well tolerated and effective endocrine therapy for postmenopausal women with metastatic breast cancer who have been heavily pretreated with prior therapies. The novel mechanism of action of fulvestrant reduces the likelihood of cross-resistance with other endocrine therapies and therefore this agent may be active in patients who have proved to be resistant to treatments such as tamoxifen or AIs. The use of fulvestrant earlier in the sequence of endocrine treatments may achieve better responses than observed in this heavily pretreated patient population.

Lower-Category Benign Breast Disease and the Risk of Invasive Breast Cancer

BACKGROUND

The risk of invasive breast cancer associated with benign breast disease (BBD) other than atypical hyperplasia and in situ breast cancer, especially with nonproliferative diagnosis, has not been explored extensively. This report evaluates the risk of breast cancer associated with this lower-category BBD (LC-BBD).

METHODS

11 307 women without prior history of atypical hyperplasia or in situ breast cancer at randomization (1992-1997) were identified from the cohort of the National Surgical Adjuvant Breast and Bowel Project's Breast Cancer Prevention Trial. Pathologic findings from breast biopsy reports through August 2002 were reviewed, and Cox proportional hazards models were used to determine the relative risks (RRs) of breast cancer with 95% confidence intervals (CIs). The relative risks of breast cancer for LC-BBD were adjusted for treatment and for breast cancer risk as determined by the modified Gail model.

RESULTS

Of the 11 307 women, 1376 had LC-BBD, of whom 47 developed breast cancer, and of the 9931 women without LC-BBD, 291 developed breast cancer. The RR of breast cancer for women with LC-BBD relative to women without LC-BBD was 1.60 (95% CI = 1.17 to 2.19). Among women 50 years of age and older, the RR of breast cancer for those with LC-BBD was 1.95 (95% CI = 1.29 to 2.93). After adjustment for treatment and breast cancer risk, the RR of breast cancer for women with LC-BBD was 1.41 (95% CI = 1.03 to 1.94).

CONCLUSIONS

Women with LC-BBD had a statistically significant increased risk of breast cancer. The elevation of breast cancer risk was especially evident in women 50 years of age and older. Furthermore, this risk was independent of that associated with key epidemiologic breast cancer risk factors.

Effects of tamoxifen on benign breast disease in women at high risk for breast cancer

BACKGROUND

In 1998 the National Surgical Adjuvant Breast and Bowel Project (NSABP) demonstrated that tamoxifen treatment reduced the incidence of both invasive and noninvasive breast cancer in women at high risk for the disease. We examined the effect of tamoxifen treatment on the incidence of benign breast disease and the number of breast biopsies in the same group of women.

METHODS

We examined the medical records of 13 203 women with follow-up who participated in the NSABP Breast Cancer Prevention Trial. Included in this analysis were women who had undergone a breast biopsy and who had histologic diagnoses of adenosis, cyst, duct ectasia, fibrocystic disease, fibroadenoma, fibrosis, hyperplasia, or metaplasia. The relative risk (RR) for each histologic diagnosis was estimated for women who received tamoxifen and for women who received placebo. We also tallied the number of biopsies that women in the placebo and tamoxifen groups underwent.

RESULTS

Overall, tamoxifen treatment reduced the risk of benign breast disease by 28% (RR = 0.72, 95% confidence interval [CI] = 0.65 to 0.79). Tamoxifen therapy resulted in statistically significant reductions in the risk of adenosis (RR = 0.59, 95% CI = 0.47 to 0.73), cyst (RR = 0.66, 95% CI = 0.58 to 0.75), duct ectasia (RR = 0.72, 95% CI = 0.53 to 0.97), fibrocystic disease (RR = 0.67, 95% CI = 0.58 to 0.77), hyperplasia (RR = 0.60, 95% CI = 0.50 to 0.71), and metaplasia (RR = 0.51, 95% CI = 0.41 to 0.62). Tamoxifen therapy also reduced the risk for fibroadenoma (RR = 0.77, 95% CI = 0.56 to 1.04) and fibrosis (RR = 0.86, 95% CI = 0.72 to 1.03). Compared with the placebo group, the tamoxifen group had 29% (95% CI = 23% to 34%) fewer biopsies (1048 versus 1469) and 19% fewer women who underwent a biopsy (811 versus 1019). This resulted in a 29% reduction in the risk of biopsy in women treated with tamoxifen (RR = 0.71, 95% CI = 0.66 to 0.77). This risk reduction occurred predominantly in women younger than 50 years.

CONCLUSION

Women in this study who received tamoxifen, especially younger women (i.e., <50 years), had a reduced incidence of clinically detected benign breast disease and underwent fewer breast biopsies.

Moving forward: Herceptin in the adjuvant setting

HER2 overexpression/amplification, which is an early event in breast cancer development, is associated with a poor prognosis and may predict response to therapy. Herceptin, an anti-HER2 monoclonal antibody, has shown significant efficacy in the treatment of HER2-positive metastatic breast cancer and appears to provide greater benefit the earlier the drug is given. Moreover, Herceptin also demonstrates a favorable safety profile and is associated with quality-of-life benefits. Taken together, these factors provide the rationale for moving this drug into the adjuvant setting, and four large-scale trials that will involve a total of more than 12,000 women with HER2-positive primary breast cancer have been undertaken to address this issue. In the United States, NSABP trial B31 and the Intergroup N9831 trial will investigate Herceptin in combination with the standard US regimen of anthracycline/cyclophosphamide followed by paclitaxel. Trial BCIRG 006, which is being conducted globally, will examine Herceptin in combination with platinum salts/docetaxel. The HERA Trial, involving countries outside the US, will examine q3-weekly Herceptin monotherapy given for 1 and 2 years after the completion of adjuvant chemo-/radiation therapy. The breadth of the ongoing Herceptin adjuvant trials will potentially allow the optimal treatment approach to be identified.

Real-world performance of HER2 testing--National Surgical Adjuvant Breast and Bowel Project experience

Trastuzumab (Herceptin) provides clinical benefits for patients diagnosed with advanced breast cancers that have overexpressed the HER2 protein or have amplified the HER2 gene. The National Surgical Adjuvant Breast and Bowel Project (NSABP) Protocol B-31 is designed to test the advantage of adding Herceptin to the adjuvant chemotherapeutic regimen of doxorubicin and cyclophosphamide followed by paclitaxel (Taxol) in the treatment of stage II breast cancer with HER2 overexpression or gene amplification. Eligibility is based on HER2 assay results submitted by the accruing institutions. We conducted a central review of the first 104 cases entered in this trial on the basis of immunohistochemistry (IHC) results. We found that 18% of the community-based assays, which were used to establish the eligibility of patients to participate in the B-31 study, could not be confirmed by HercepTest IHC or fluorescence in situ hybridization (FISH) by a central testing facility. This report provides a snapshot of the quality of HER2 assays performed in laboratories nationwide.

Breast cancer chemoprevention: current status and future directions

Cancer prevention is a relatively young concept. Perhaps the greatest strides in cancer research that have been made in the prevention arena have been in breast cancer. In this article we examine the meaning of "prevention" and discuss several of the trials under way or completed, including the National Surgical Adjuvant Breast and Bowel Project (NSABP) Breast Cancer Prevention Trial. Semin Oncol 28:253-259.