P Klare

Tumor-Infiltrating Lymphocytes and Response to Neoadjuvant Chemotherapy With or Without Carboplatin in Human Epidermal Growth Factor Receptor 2–Positive and Triple-Negative Primary Breast Cancers

PURPOSE Modulation of immunologic interactions in cancer tissue is a promising therapeutic strategy. To investigate the immunogenicity of human epidermal growth factor receptor 2 (HER2) -positive and triple-negative (TN) breast cancers (BCs), we evaluated tumor-infiltrating lymphocytes (TILs) and immunologically relevant genes in the neoadjuvant GeparSixto trial. PATIENTS AND METHODS GeparSixto investigated the effect of adding carboplatin (Cb) to an anthracycline-plus-taxane combination (PM) on pathologic complete response (pCR). A total of 580 tumors were evaluated before random assignment for stromal TILs and lymphocyte-predominant BC (LPBC). mRNA expression of immune-activating (CXCL9, CCL5, CD8A, CD80, CXCL13, IGKC, CD21) as well as immunosuppressive factors (IDO1, PD-1, PD-L1, CTLA4, FOXP3) was measured in 481 tumors. RESULTS Increased levels of stromal TILs predicted pCR in univariable (P < .001) and multivariable analyses (P < .001). pCR rate was 59.9% in LPBC and 33.8% for non-LPBC (P < .001). pCR rates ≥ 75% were observed in patients with LPBC tumors treated with PMCb, with a significant test for interaction with therapy in the complete (P = .002) and HER2-positive (P = .006), but not the TNBC, cohorts. Hierarchic clustering of mRNA markers revealed three immune subtypes with different pCR rates (P < .001). All 12 immune mRNA markers were predictive for increased pCR. The highest odds ratios (ORs) were observed for PD-L1 (OR, 1.57; 95% CI, 1.34 to 1.86; P < .001) and CCL5 (OR, 1.41; 95% CI, 1.23 to 1.62; P < .001). CONCLUSION Immunologic factors were highly significant predictors of therapy response in the GeparSixto trial, particularly in patients treated with Cb. After further standardization, they could be included in histopathologic assessment of BC.

Neoadjuvant carboplatin in patients with triple-negative and HER2-positive early breast cancer (GeparSixto; GBG 66): a randomised phase 2 trial

BACKGROUND Preclinical data suggest that triple-negative breast cancers are sensitive to interstrand crosslinking agents, and that synergy may exist for the combination of a taxane, trastuzumab, and a platinum salt for HER2-positive breast cancer. We therefore aimed to assess the efficacy of the addition of carboplatin to neoadjuvant therapy for triple-negative and HER2-positive breast cancer. METHODS Patients with previously untreated, non-metastatic, stage II-III, triple-negative breast cancer and HER2-positive breast cancer were enrolled. Patients were treated for 18 weeks with paclitaxel (80 mg/m(2) once a week) and non-pegylated liposomal doxorubicin (20 mg/m(2) once a week). Patients with triple-negative breast cancer received simultaneous bevacizumab (15 mg/kg intravenously every 3 weeks). Patients with HER2-positive disease received simultaneous trastuzumab (8 mg/kg initial dose with subsequent doses of 6 mg/kg intravenously every 3 weeks) and lapatinib (750 mg daily). Patients were randomly assigned in a 1:1 ratio with dynamic allocation and minimisation, stratified by biological subtype and Ki-67 level to receive, at the same time as the backbone regimens, either carboplatin (AUC 1·5 [2·0 for the first 329 patients] once a week) or no carboplatin. The primary endpoint the proportion of patients who achieved a pathological complete response (defined as ypT0 ypN0), analysed for all patients who started treatment; a p value of less than 0·2 was deemed significant for the primary endpoint. This trial is registered with ClinicalTrials.gov, number NCT01426880. FINDINGS 296 patients were randomly assigned to receive carboplatin and 299 to no additional carboplatin, of whom 295 and 293 started treatment, respectively. In this final analysis, 129 patients (43·7%, 95% CI 38·1-49·4) in the carboplatin group achieved a pathological complete response, compared with 108 patients (36·9%, 31·3-42·4) without carboplatin (odds ratio 1·33, 95% CI 0·96-1·85; p=0·107). Of the patients with triple-negative breast cancer, 84 (53·2%, 54·4-60·9) of 158 patients achieved a pathological complete response with carboplatin, compared with 58 (36·9%, 29·4-44·5) of 157 without (p=0·005). Of the patients with HER2-positive tumours, 45 (32·8%, 25·0-40·7) of 137 patients achieved a pathological complete response with carboplatin compared with 50 (36·8%, 28·7-44·9) of 136 without (p=0·581; test for interaction p=0·015). Haematological and non-haematological toxic effects that were significantly more common in the carboplatin group than in the no-carboplatin group included grade 3 or 4 neutropenia (192 [65%] vs 79 [27%]), grade 3 or 4 anaemia (45 [15%] vs one [<1%]), grade 3 or 4 thrombocytopenia (42 [14%] vs one [<1%]), and grade 3 or 4 diarrhoea (51 [17%] vs 32 [11%]); carboplatin was more often associated with dose discontinuations (141 [48%] with carboplatin and 114 [39%] without carboplatin; p=0·031). The frequency of grade 3 or 4 haematological events decreased from 82% (n=135) to 70% (n=92) and grade 3 or 4 non-haematological events from 78% (n=128) to 59% (n=77) in the carboplatin arm when the dose of carboplatin was reduced from AUC 2·0 to 1·5. INTERPRETATION The addition of neoadjuvant carboplatin to a regimen of a taxane, an anthracycline, and targeted therapy significantly increases the proportion of patients achieving a pathological complete response. This regimen seems to increase responses in patients with triple-negative breast cancer, but not in those with HER2-positive breast cancer. FUNDING GlaxoSmithKline, Roche, and Teva.

Phase II Study of Capecitabine Plus Trastuzumab in Human Epidermal Growth Factor Receptor 2–Overexpressing Metastatic Breast Cancer Pretreated With Anthracyclines or Taxanes

PURPOSE The oral fluoropyrimidine carbamate, capecitabine, is a highly active and well-tolerated treatment for metastatic breast cancer. In patients treated previously with anthracyclines and taxanes, capecitabine is an approved single-agent therapy. Trastuzumab, a monoclonal antibody targeting the human epidermal growth factor receptor 2 (HER-2), is also highly active in HER-2-overexpressing breast cancer. We have conducted a phase II study to confirm activity and feasibility of capecitabine and trastuzumab in combination in HER-2-overexpressing advanced/metastatic breast cancer. PATIENTS AND METHODS Twenty-seven patients with HER-2-overexpressing metastatic breast cancer previously treated with anthracyclines and/or taxanes received oral capecitabine 1,250 mg/m(2) bid for 14 days followed by a 7-day rest period combined with intravenous trastuzumab 4 mg/kg body weight on day 1 (loading dose) followed by 2 mg/kg weekly. RESULTS Capecitabine/trastuzumab treatment achieved objective responses in 12 patients (45%), including complete response in four patients (15%) and partial response in eight patients (30%). Disease was stabilized in an additional nine patients (33%). The median overall survival time was 28 months, and the median progression-free survival time was 6.7 months. The safety profile of the combination was favorable and predictable, with a low incidence of grade 3/4 adverse events. The most common adverse events were pain, hand-foot syndrome, and GI toxicities. Severe myelosuppression was rare and severe alopecia did not occur. CONCLUSION These data confirm that the combination of capecitabine and trastuzumab is highly active in patients with HER-2-overexpressing anthracycline- and/or taxane-pretreated breast cancer, with only slight restrictions regarding quality of life.

Abstract S2-04: Early survival analysis of the randomized phase II trial investigating the addition of carboplatin to neoadjuvant therapy for triple-negative and HER2-positive early breast cancer (GeparSixto)

Introduction Addition of carboplatin to anthracycline/taxane-based neoadjuvant chemotherapy has shown to improve pathological complete response (pCR; ypT0 ypN0) rates in patients with triple-negative breast cancer in two large phase II studies (GeparSixto: von Minckwitz et al. Lancet Oncol 2014; CALGB 40603: Sikov et al. J Clin Oncol 2015). Participants of the GeparSixto study with triple-negative tumors showed an improvement of pCR rate from 36.9 to 53.2% by the addition of carboplatin (p=0.005); however, no statistically significant difference in pCR rate was observed in the HER2-positive subgroup (36.8 vs 32.8%, respectively). A greater benefit with carboplatin was observed in patients with BRCA mutations or a high homologous recombination deficiency (HRD score) in the tumor (pCR rate of 30% compared to 10% for patients without HRD). So far, it is unknown whether these effects on pCR translate into a survival benefit for the patients. We here report an early survival analysis of the GeparSixto study. Patients and Methods In the GeparSixto trial (NCT01426880), patients were treated for 18 weeks with paclitaxel 80mg/m2 q1w and non-pegylated-liposomal doxorubicin (NPLD) 20mg/m2 q1w. Patients with TNBC (N=315) received concurrently bevacizumab 15mg/kg i.v. q2w until surgery. Patients with HER2+ disease (N=273) received concurrently trastuzumab 6(8)mg/kg q3w and lapatinib 750mg daily. All patients were randomized 1:1 to receive concurrently carboplatin AUC 1.5-2.0 q1w vs no carboplatin, stratified by subtype (HER2+ vs TNBC). Carboplatin dose was reduced from AUC 2.0 to 1.5 by an amendment after 330 patients. Primary objective was pCR rate (ypT0 ypN0). Loco-regional invasive recurrence free survival (LRRFS), distant-disease- free survival (DDFS), invasive disease-free survival (IDFS), and overall survival (OS) were secondary objectives. Results 595 patients were recruited (8/2011 - 12/2012) in 51 German centers. 296 patients were randomly assigned to receive carboplatin and 299 to no additional carboplatin, of whom 295 and 293 started treatment, respectively. So far, 82 events have been reported after a median of 28 months follow-up. Analysis of updated events by treatment arm in the full study population as well as in the TNBC and HRD subgroups will be presented. Conclusion Even if the GeparSixto study was not powered to show carboplatin effects on survival, the expected results will help to assess the overall benefit of carboplatin in TNBC and the power of pCR to predict for DFS and OS. Citation Format: von Minckwitz G, Loibl S, Schneeweiss A, Salat CT, Rezai M, Zahm D-M, Klare P, Blohmer J-U, Tesch H, Khandan F, Fasching PA, Jakisch C, Nekljudova V, Untch M. Early survival analysis of the randomized phase II trial investigating the addition of carboplatin to neoadjuvant therapy for triple-negative and HER2-positive early breast cancer (GeparSixto). [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr S2-04.

Abstract S1-06: Increased tumor-associated lymphocytes predict benefit from addition of carboplatin to neoadjuvant therapy for triple-negative and HER2-positive early breast cancer in the GeparSixto trial (GBG 66)

Background: We have recently described a significantly increased pCR rate in triple-negative breast cancer with addition of carboplatin to a non-pegylated liposomal doxorubicin/taxane (MC) combination in the neoadjuvant Geparsixto study (von Minckwitz et al, ASCO, 2013). Here we report the results of prospective biomarker analyses performed in Geparsixto. Methods: Geparsixto investigates the effect of adding carboplatin to MC for the treatment of patients with HER2+ve and triple-negative (TN) primary BC. All HER2+ve patients received trastuzumab and lapatinib, all TN patients received bevacizumab. As part of the central pathology assessment, we prospectively evaluated tumor-associated lymphocytes (TILs) in 580 core biopsies. We used the parameters stromal lymphocytes (strLy) and lymphocyte-predominant breast cancer (LPBC, ≥60%TILs) as previously described (Denkert et al, JCO, 2010). In addition, Ki67 (n = 588) was measured by immunohistochemistry and p53 mutations in Exons 5-8 (n = 444) were evaluated by Sanger sequencing. Pathological complete remission (pCR) was defined as ypT0ypN0. Results: 24.7% of the 588 patients had a LPBC. These patients had an increased pCR rate of 60.3%, compared to 35.8% for the non-LPBC tumors (p Ki67>20% was associated with an increased pCR rate of 46.6%, compared to 27% in tumors with lower proliferation (p Conclusion: Our results show that the interaction with host immune response is relevant for response to chemotherapy, this effect is particularly strong with the addition of carboplatin. Tumor-associated lymphocytes as a continuous parameter as well as LPBC as a tumor subgroup are predictive for response to neoadjuvant chemotherapy. In particular with regard to the relevant toxicity of the MC+carboplatin combination, the integration of immunological biomarkers would be helpful to identify the patients with the highest benefit from the addition of carboplatin. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr S1-06.

Role of TP53 mutations in triple negative and HER2-positive breast cancer treated with neoadjuvant anthracycline/taxane-based chemotherapy

Background TP53 mutations are frequent in breast cancer, however their clinical relevance in terms of response to chemotherapy is controversial. Methods 450 pre-therapeutic, formalin-fixed, paraffin-embedded core biopsies from the phase II neoadjuvant GeparSixto trial that included HER2-positive and triple negative breast cancer (TNBC) were subjected to Sanger sequencing of exons 5-8 of the TP53 gene. TP53 status was correlated to response to neoadjuvant anthracycline/taxane-based chemotherapy with or without carboplatin and trastuzumab/lapatinib in HER2-positive and bevacizumab in TNBC. p53 protein expression was evaluated by immunohistochemistry in the TNBC subgroup. Results Of 450 breast cancer samples 297 (66.0%) were TP53 mutant. Mutations were significantly more frequent in TNBC (74.8%) compared to HER2-positive cancers (55.4%, P < 0.0001). Neither mutations nor different mutation types and effects were associated with pCR neither in the whole study group nor in molecular subtypes (P > 0.05 each). Missense mutations tended to be associated with a better survival compared to all other types of mutations in TNBC (P = 0.093) and in HER2-positive cancers (P = 0.071). In TNBC, missense mutations were also linked to higher numbers of tumor-infiltrating lymphocytes (TILs, P = 0.028). p53 protein overexpression was also linked with imporved survival (P = 0.019). Conclusions Our study confirms high TP53 mutation rates in TNBC and HER2-positive breast cancer. Mutations did not predict the response to an intense neoadjuvant chemotherapy in these two molecular breast cancer subtypes.

Abstract P1-09-02: Homologous repair deficiency (HRD) as measure to predict the effect of carboplatin on survival in the neoadjuvant phase II trial GeparSixto in triple-negative early breast cancer

Introduction Addition of carboplatin to anthracycline/taxane-based neoadjuvant chemotherapy has shown to improve pathological complete response (pCR; ypT0 ypN0) rates in patients with triple-negative breast cancer (TNBC) in two large phase II studies (GeparSixto: von Minckwitz et al, Lancet Oncol 2014, CALGB 40603: Sikov WM, J Clin Oncol 2015). Participants of the GeparSixto study showed an improvement of pCR rate from 36.9 to 53.2% (p=0.005) and DFS by absolute 9% (HR 0.56 95% CI 0.33-0.96] p=0.035) with the addition of carboplatin in the TNBC subgroup. No effect was observed in the HER2-positive subgroup. We here report results on homologous repair deficiency (HRD) status in relation to pCR and DFS in the TNBC subgroup. Patients and Methods In the GeparSixto trial (NCT01426880), patients were treated for 18 weeks with paclitaxel 80mg/m2 q1w and non-pegylated-liposomal doxorubicin (NPLD) 20mg/m2 q1w. Patients with TNBC (N=315) received concurrently bevacizumab 15mg/kg i.v. q2w until surgery. All patients were randomized 1:1 to receive concurrently carboplatin AUC 1.5-2 q1w vs no carboplatin. Carboplatin dose was reduced from AUC 2.0 to 1.5 by an amendment after 330 patients. Primary objective is pCR rate (ypT0 ypN0). Event free survival (EFS), and overall survival (OS) were secondary objectives. HR Deficiency status was assessed on FFPE material from pretherapeutic core biopsies. HR Deficiency was defined as either HRD score high or a BRCA mutation. Results HRD status was measurable in 193 of 315 TNBC patients. 101 patients of them were randomly assigned to receive carboplatin and 92 to no additional carboplatin. After median follow-up of 34.3 months 43 event free survival (EFS) events have been reported. HR deficiency was detected in 136 (70.5%) tumors of which 79 (58.1%) showed high HRD score with intact tBRCA. HR deficiency independently predicted pCR (ypT0is ypN0) (odds ratio (OR) 2.506, CI 1.243-5.051, p=0.009). Adding carboplatin to PM significantly increased the pCR rate from 36.6% to 63.2% in HR deficient tumors with intact tBRCA (p=0.018), only marginally from 61.9% to 72.7% in BRCA mutated tumors (p=0.406), and moderately from 20.0% to 40.7% in HR non-deficient tumors (p=0.086). In general, patients with HRD deficient tumors had a better ESF than non HRD deficient ones (HR 1.805 (0.985-3.309); p=0.0526). Patients with high HRD score had an insignificant trend towards an improved EFS compared to those with low HRD score (HR 1.546 (0.764-3.127) p=0.2223). HRD deficiency did not predict carboplatin effect in patients without BRCA mutation (HR 0.8617). In multivariable analysis, only therapy, clinical nodal status before treatment, and lymphocyte predominant breast cancer were significant prognostic on EFS. Conclusion Within the GeparSixto study HR deficiency (either HRD score high or BRCA mutation) was associated with a higher pCR in general and an improved EFS. The effect of carboplatin could not be predicted by HR deficiency in this relatively small study. However, the results will help to understand the role of HR deficiency and the value of the HRD score in TNBC especially in patients without BRCA mutation. Citation Format: von Minckwitz G, Timms K, Untch M, Elkin EP, Hahnen E, Fasching PA, Schneeweiss A, Salat CT, Rezai M, Blohmer J-U, Zahm D-M, Jackisch C, Gerber B, Klare P, Kummel S, Paepke S, Schmutzler R, Chau S, Reid J, Hartman A-R, Nekljudova V, Weber KE, Loibl S. Homologous repair deficiency (HRD) as measure to predict the effect of carboplatin on survival in the neoadjuvant phase II trial GeparSixto in triple-negative early breast cancer [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 P1-09-02.

Survival analysis of carboplatin added to an anthracycline/taxane-based neoadjuvant chemotherapy and HRD score as predictor of response – final results from GeparSixto

Background In the neoadjuvant GeparSixto study, adding carboplatin to taxane- and anthracycline-based chemotherapy improved pathological complete response (pCR) rates in patients with triple-negative breast cancer (TNBC). Here, we present survival data and the potential prognostic and predictive role of homologous recombination deficiency (HRD). Patients and methods Patients were randomized to paclitaxel plus nonpegylated liposomal doxorubicin (Myocet®) (PM) or PM plus carboplatin (PMCb). The secondary study end points disease-free survival (DFS) and overall survival (OS) were analyzed. Median follow-up was 47.3 months. HRD was among the exploratory analyses in GeparSixto and was successfully measured in formalin-fixed, paraffin-embedded tumor samples of 193/315 (61.3%) participants with TNBC. Homologous recombination (HR) deficiency was defined as HRD score ≥42 and/or presence of tumor BRCA mutations (tmBRCA). Results A significantly better DFS (hazard ratio 0.56, 95% CI 0.34-0.93; P = 0.022) was observed in patients with TNBC when treated with PMCb. The improvement of OS with PMCb was not statistically significant. Additional carboplatin did not improve DFS or OS in patients with HER2-positive tumors. HR deficiency was detected in 136 (70.5%) of 193 triple-negative tumors, of which 82 (60.3%) showed high HRD score without tmBRCA. HR deficiency independently predicted pCR (ypT0 ypN0) [odds ratio (OR) 2.60, 95% CI 1.26-5.37, P = 0.008]. Adding carboplatin to PM significantly increased the pCR rate from 33.9% to 63.5% in HR deficient tumors (P = 0.001), but only marginally in HR nondeficient tumors (from 20.0% to 29.6%, P = 0.540; test for interaction P = 0.327). pCR rates with carboplatin were also higher (63.2%) than without carboplatin (31.7%; OR 3.69, 1.46-9.37, P = 0.005) in patients with high HRD score but no tmBRCA. DFS rates were improved with addition of carboplatin, both in HR nondeficient (hazard ratio 0.44, 0.17-1.17, P = 0.086) and HR deficient tumors (hazard ratio 0.49, 0.23-1.04, P = 0.059). Conclusions The addition of carboplatin to neoadjuvant PM improved DFS significantly in TNBC. Long-term survival analyses support the neoadjuvant use of carboplatin in TNBC. HR deficiency in TNBC and HRD score in non-tmBRCA TNBC are predictors of response. HRD does not predict for carboplatin benefit.

Abstract P1-13-05: GAIN-2: Adjuvant phase III trial to compare intense dose-dense (idd) treatment with EnPC to tailored dose-dense (dt) therapy with dtEC-dtD for patients with high-risk early breast cancer: Results of the second safety interim analyses

Background: GAIN-2 compares the effectiveness and safety of a predefined intense dose-dense regimen (EnPC) vs. a dose-dense regimen with modification of single doses depending on individual hematological and non-hematological toxicities (dtEC-dtD) (NCT01690702). Moreover, the Trastuzumab substudy compares the subcutaneous administration of the drug to the abdominal wall vs. thigh. Methods: The primary objective of the GAIN-2 trial is to compare the invasive disease-free survival (iDFS) in patients with high-risk primary breast cancer (luminal A ≥4 N+; luminal B N+; HER2+ and TNBC N0/N+). Patients are randomized between EnPC (epirubicin 150 mg/m 2 q2w x 3, nab-Paclitaxel 330 mg/m 2 q2w x 3, cyclophosphamide 2000 mg/m 2 q2w x 3) or dtEC-dtD (dd/tailored epirubicin/cyclophosphamide q2w x 4 followed by dd/tailored docetaxel q2w x 4) Two safety interim analyses after 200 (Noeding et al. Ann Oncol 2014) and 900 patients who have completed chemotherapy were planned. We present the results of the second safety analysis. In addition to the standard analyses for hematological and non-hematological toxicities, any affections of the cranial nerves as well as the rate of macula degenerations and anaphylactic reactions are of special interest. Results: Between 09/2012 and 05/2015 a total of 1473 patients have been randomized (EnPC n=734; dtEC-dtD n=739). Among those, 84 patients have been included in the trastuzumab substudy. No safety data are currently available for the substudy. Median age was 52 years and median body-mass-index 26. In terms of hematological adverse events, the rate of febrile neutropenia grade 3-4 (12% vs. 8%) and thrombopenia grade 3-4 (12% vs. 5%) was significantly increased in the EnPC arm. As for non-hematological side effects, there were significantly more patients developing an increase in alkaline phosphatase (59% vs. 40%), ALAT (69% vs. 59%), peripheral sensory neuropathy (83% vs. 68%), arthralgia (63% vs. 49%), myalgia (48% vs. 41%) and bone pain (25% vs. 17%) in the EnPC arm, whereas nosebleed (10% vs. 25%), edema (13% vs. 26%) and hand-foot syndrome (12% vs. 28%) were more common in the dtEC-dtD arm. We observed two treatment related deaths, both in the dtEC-dtD arm (cause of death: acute respiratory distress syndrome and pneumonia). There were no differences between the treatment arms for the toxicities of special interest. In the EnPC arm, overall 30% of the patients required dose-reductions due to hematological toxicities compared with only 10% in the dtEC-dtD arm (p 2 followed by docetaxel 100 mg/m 2 ) in more than one third of the patients receiving dtEC-dtD. In 9% of women a reduction was required in the 4th cycle of docetaxel. Conclusion: This interim safety analysis from a prospectively randomized trial investigating iddEnPC with predefined doses and a toxicity adapted idd/tailored strategy (dtEC-dtD) showed no additional or unexpected safety signals in the iddEnPC or dtEC-dtD arm. Therefore, no modifications in the conduction of the study are necessary and the study continues as expected. Citation Format: Mobus V, Luck H-J, Forstbauer H, Wachsmann G, Ober A, Schneeweiss A, Christensen B, von Abel E, Grischke E-M, Hoffkes H-G, Klare P, Yon-Dschun K, Schmatloch S, Furlanetto J, Burchardi N, von Minckwitz G, Loibl S. GAIN-2: Adjuvant phase III trial to compare intense dose-dense (idd) treatment with EnPC to tailored dose-dense (dt) therapy with dtEC-dtD for patients with high-risk early breast cancer: Results of the second safety interim analyses. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-13-05.

264PDGAIN2: ADJUVANT PHASE III TRIAL COMPARING AN INTENSIFIED DOSE-DENSE ADJUVANT THERAPY WITH ENPC COMPARED WITH A DOSE-DENSE, DOSE-ADAPTED THERAPY WITH DTEC DTDOCETAXEL IN PATIENTS WITH PRIMARY BREAST CANCER AND A HIGH RISK OF RECURRENCE

ABSTRACT Aim: Combined chemotherapy requires compromises in terms of dosage and treatment interval due to toxicities. The sequential administration of monotherapies allows high doses of single substances and dose-dense intervals. So far, such regimens have proved to be very effective in early breast cancer with high risk of recurrence. Nab-paclitaxel (nP) leads to a more favorable toxicity profile and greater efficacy compared with solvent-based taxanes. Methods: The GAIN2 study compares toxicity and efficacy of a pre-defined dose-dense high-dose regimen (EnPC) with a dose-dense regimen, where single doses are adjusted depending on individual haematological and non-haematological toxicities (dtEC-dtD). Primary endpoint is the invasive disease-free survival in patients with primary node-positive or high-risk node-negative breast cancer. Two safety interim analyses after 200 and 900 patients who have completed chemotherapy are planned. The results of the first safety analysis will be presented. In addition to the standard analyses for haematological and non-haematological toxicities, any affections of the cranial nerves as well as the rate of macular degeneration and anaphylactic reactions are of special interest. Results: In terms of hematological adverse events, the rate of febrile neutropenia grade 3-4 (14% vs. 5%) and thrombocytopenia grade 3-4 (14% vs. 5%) was significantly increased in the EnPC arm. As for the non-haematological side effects, there were significantly more patients developing anorexia (grade 1-4) in the EnPC arm. There were no differences between the treatment arms for the toxicities of special interest. In the EnPC arm, 28% required dose-reductions due to hematological toxicities compared with only 11% in the dtEC dtD arm (p = 0.002). The dose could be escalated to the maximum in half of the patients receiving dtEC dtD. In 7% of women a reduction was required in the 4th cycle of docetaxel. Conclusions: Due to similar toxicity profiles, the study will be continued without changes. Disclosure: A. Schneeweiss: Honoraria, Research Funding and Advisory Role: Celgene and Roche; G. von Minckwitz: Honoraria and Research Funding: Amgen, Celgene and Roche; V. Mobus: Honoraria and Research Funding: Amgen, GSK, Sanofi-Aventis, Pfizer, Roche. All other authors have declared no conflicts of interest.