Abstract P2-13-04: Impact of the adjuvant treatment with trastuzumab in HER2 positive breast cancer in the real-world setting. Analysis of two cohorts (1997-2005/2006-2015) in 1970 patients

INTRODUCTION: Although large randomized trials assessing the benefit of adjuvant trastuzumab in HER2-positive (HER2+) breast cancer have clearly demonstrated a significant improvement in long-term survival, it is necessary to know the impact of the use of trastuzumab adjuvant in the real life population, which includes patients frequently excluded from clinical trials, such as those with very small tumors without node involvement, or advanced age. The objective of this study is to describe the outcomes of women who received adjuvant trastuzumab for HER2+ cáncer since it was approved in 2006, compared with a previous cohort of HER2+ patients not treated with trastuzumab in 7 Spanish centers.

METHODS: Women with newly diagnosed stage I-III, HER2+ breast cancer, between 1997 and 2015 were included in the study. Two cohorts were considered: The No-Trastuzumab cohort (No-T), between 1997 and 2005, and the Trastuzumab cohort (T) with trastuzumab-treated women between 2006 and 2015. Kaplan-Meier estimates were used to evaluate DFS and OS. Additionally, cohorts were analyzed by pathologic tumour size, lymph node involvement and hormonal receptor status to stratify outcome measures.

RESULTS: A total of 2134 patients were identified. In 164 cases, data were insufficient or the follow-up incomplete. Therefore, the final analysis included 1970 patients, of whom 539 belong to the "No-T" cohort and 1431 to the "T" cohort. The median follow-up was 81 months. Median age: 53 years [22-98]. A total of 699 patients had T1 tumors [43% in the "No-T" cohort vs 33% in the "T" cohort]. 55% of the cases were N0 [58% and 54% in the "No-T" and "T" cohorts respectively]. The status of the hormonal receptors was well balanced between groups [36% ER negative in both]. Regarding the type of adjuvant treatment administered, in the "T" cohort more patients received adjuvant chemotherapy [65% vs 97%] and also in the “T” group combinations of taxanes and anthracyclines were more frequent [14% vs 72%]. The proportion of adjuvant endocrine therapy was similar in both groups [37% vs 34%].

In the “T” cohort, median Disease Free Survival (DFS) was not-reached, compared with 149 months in the “No-T” group. 5-year DFS was 83% vs 65% respectively [p<0.001]. 5-year DFS was also superior and statistically significant in all the subgroups analyzed, including patients with T1 tumors (87% vs 57%), N0 (87% vs 78%), patients T1N0 (88% vs 74%) and HR positive (86% vs 71%) or negative (78% vs 50%). Similarly, Overall Survival (OS) was increased in patients treated with Trastuzumab (median: 224 months vs not-reached, 5-year OS: 92% vs 75% [p <0.001].) 5-year OS was also statistically superior in the T1 subgroup (92% vs 72%), and N0 (95% vs 88%). [p<0.001 in all subanalysis].

CONCLUSIONS: Adjuvant treatment with Trastuzumab under conditions of real clinical practice in HER2+ early breast cancer, shows a highly significant benefit in terms of DFS and OS, regardless of the stage of the disease or other clinical variables. A very important benefit was reached in patients with small tumors, node-negative disease, or both conditions (T1N0). The benefit was also obtained regardless of the expression of hormonal receptors.

Citation Format: Rodriguez CA, Garcia-Gomez J, Ribelles N, Gavila J, Pernas S, Rodriguez-Lescure A, Urrutikoetxea A, Pernaut C, Lopez A, Garcia-Mata J. Impact of the adjuvant treatment with trastuzumab in HER2 positive breast cancer in the real-world setting. Analysis of two cohorts (1997-2005/2006-2015) in 1970 patients [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 P2-13-04.

Abstract P2-08-04: Prediction of distant recurrence by EndoPredict in patients with estrogen receptor-positive, HER2-negative breast cancer who received adjuvant endocrine therapy plus chemotherapy (ET+C) or endocrine therapy alone (ET)

Background: EndoPredict (EPclin) is a validated prognostic test combining expression of 12 cancer-related genes for breast cancer patients with estrogen receptor (ER) positive, HER2-negative disease who received 5 years of endocrine therapy (Buus et al., 2017; Dubsky et al. 2012) and for women who received chemotherapy (Martin et al., 2014). Here, we determine the EPclin and 10-year distant recurrence free interval (DRFI) rates for patients who received adjuvant endocrine therapy plus chemotherapy (ET+C) or endocrine therapy alone (ET) using data from five large clinical trials.

Methods: A total of 3746 women with ER-positive, HER2-negative disease were included in this analysis. 2630 patients received 5 years of ET alone (ABCSG-6/8, TransATAC) and 1116 patients received ET+C (GEICAM 2003-02/9906). EPclin incorporates tumor size and nodal status and accounts for different EPClin scores between ET+C and ET alone cohorts. The primary objective was to evaluate the 10-year DRFI rates as a continuous function of EPclin separately for patients in ET+C and ET. Secondary objectives included assessing the difference in the prognostic ability of EPclin between ET+C and ET overall (years 0-10) and for specific follow-up periods (years 0-5 and years 5-10). The primary endpoint was DRFI and the secondary endpoint was breast cancer free interval (BCFI). Cox proportional hazard models were used to estimate 10-year DRFI rates and to assess the prognostic information provided by EPclin.

Results: All of the women on ET alone and 49% of those on ET+C were postmenopausal. Women who received ET+C had more node positive disease, more poorly differentiated tumours, and higher EPclin scores than those who received ET alone. Women who received ET+C had significantly smaller increases in 10-year DRFI rates with increasing EPclin score than those receiving ET alone (Table). EPclin was highly prognostic for DRFI in all women who received ET alone (HR=2.79 (2.49-3.13), P<0.0001) as well as in those who received ET+C (HR=2.27 (1.99-2.59), P<0.0001), both in the overall cohort and in postmenopausal women only (ET+C: HR=2.64 (2.07-3.37), P<0.0001). We observed a significant interaction between EPclin and treatment for DRFI at 10 years (Pinteraction=0.022). EPclin was highly prognostic in ET alone and ET+C in years 0-5 and in particular in years 5-10. Similar results were observed when BCFI was the endpoint.

Conclusion: In our results from a non-randomized analysis, we observed significantly smaller increases in 10-year DRFI rates with increasing EPclin scores for women who received ET+C compared to those who received ET alone. Our indirect comparisons suggest that a high EPclin score can predict chemotherapy benefit in women with ER-positive, HER2-negative disease.

10-year DRFI risks (%) (95% CI) according to EPclin score for patients who received ET+C versus ET alone. ET+CETEPclin10-year DR risk (%)10-year DR risk (%)11.1% (0.5-1.7)1.0% (0.6-1.4)22.5% (1.5-3.5)2.8% (2.1-3.5)35.7% (4.1-7.2)7.6% (6.4-8.8)412.4% (10.1-14.6)19.8% (17.6-22.0)525.8% (22.0-29.5)46.1% (40.2-51.4)

Citation Format: Sestak I, Martin M, Dubsky P, Rojo F, Cuzick J, Filipits M, Ruiz A, Buus R, Hlauschek D, Rodriguez-Lescure A, Dowsett M, Gnant M. Prediction of distant recurrence by EndoPredict in patients with estrogen receptor-positive, HER2-negative breast cancer who received adjuvant endocrine therapy plus chemotherapy (ET+C) or endocrine therapy alone (ET) [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 P2-08-04.

Predicting response and survival in chemotherapy-treated triple-negative breast cancer

BACKGROUND

In this study, we evaluated the ability of gene expression profiles to predict chemotherapy response and survival in triple-negative breast cancer (TNBC).

METHODS

Gene expression and clinical-pathological data were evaluated in five independent cohorts, including three randomised clinical trials for a total of 1055 patients with TNBC, basal-like disease (BLBC) or both. Previously defined intrinsic molecular subtype and a proliferation signature were determined and tested. Each signature was tested using multivariable logistic regression models (for pCR (pathological complete response)) and Cox models (for survival). Within TNBC, interactions between each signature and the basal-like subtype (vs other subtypes) for predicting either pCR or survival were investigated.

RESULTS

Within TNBC, all intrinsic subtypes were identified but BLBC predominated (55-81%). Significant associations between genomic signatures and response and survival after chemotherapy were only identified within BLBC and not within TNBC as a whole. In particular, high expression of a previously identified proliferation signature, or low expression of the luminal A signature, was found independently associated with pCR and improved survival following chemotherapy across different cohorts. Significant interaction tests were only obtained between each signature and the BLBC subtype for prediction of chemotherapy response or survival.

CONCLUSIONS

The proliferation signature predicts response and improved survival after chemotherapy, but only within BLBC. This highlights the clinical implications of TNBC heterogeneity, and suggests that future clinical trials focused on this phenotypic subtype should consider stratifying patients as having BLBC or not.

Phase I-II study of IV vinorelbine (VRL) and oxaliplatin (OXP) every two weeks (q2w) in metastatic breast cancer (MBC): Results of the phase I trial

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Background: The combination of VRL and OXP was shown to be effective for the treatment of NSCLC. We designed a scheme for first line MBC consisting of administering IV VRL and OXP q2w to explore potential synergistic effects, to determine the maximal tolerated dose (MTD), recommended doses (RDs) and safety of the combination. Methods: Twelve patients (pts) entered the study. Four dose levels were established: A) VRL 25 mg/m2 with OXP 80 mg/m2, B) 25/90, C) 25/100 and D) 30/90, both drugs q2w. Patients/cycles analyzed were: A) 3/15, B) 3/21, C) 3/15, D) 3/19. Results: Median age 58 y (range; 39–78), 10 pts (83%) received prior (neo)adjuvant CT. No dose limiting toxicities were found at any of the dose levels. RD was established at IV VRL 30 mg/m2 and OXP 90 mg/m2/d both administered every 2 weeks. A total of 71 cycles were analyzed. Grade 3 neutropenia occurred in 4 pts (44%) and 13% of cycles, grade 4 in 1 pt (11%) and 1% of cycles. No complications were observed. No grade 4 non-haematological toxicity was seen. Grade 3 neurotoxicity occurred in 1 pt and 2 cycles, grade 3 fatigue occurred in 1 pt and 3 cycles. 2 partial responses were observed among the 6 evaluable patients for response. Conclusions: The combination of VRL and OXP is safe in the palliative setting of MBC. Phase II study explores the efficacy and safety of the combination of VRL 30 mg/m2 and OXP 90 mg/m2 q2w. Recruitment is ongoing.

No significant financial relationships to disclose.

Epirubicin-cyclophosphamide adjuvant chemotherapy plus tamoxifen administered concurrently versus sequentially: randomized phase III trial in postmenopausal node-positive breast cancer patients. A GEICAM 9401 study

BACKGROUND

A prospective randomized clinical trial was implemented to assess whether the concomitant or the sequential addition of tamoxifen to chemotherapy provides improved clinical benefit in the adjuvant treatment of breast cancer in postmenopausal patients.

PATIENTS AND METHODS

Four-hundred and eighty-five patients with node-positive operable disease were randomized to receive tamoxifen (20 mg/day) concomitantly (CON) or sequentially (SEQ) to EC chemotherapy (epirubicin 75 mg/m(2) + cyclophosphamide 600 mg/m(2) on day 1, every 21 days for four cycles).

RESULTS

In the 474 fully evaluable patients there were 96 events; eight being second neoplasms and 88 being related to the breast cancer. Of these, 48 of 88 occurred in the CON arm and 40 of 88 in the SEQ arm. The Kaplan-Meier estimation of disease-free survival (DFS) at 5 years was 70% in the CON and 75% in the SEQ group (log-rank test, P = 0.43). Adjusted hazard ratio for treatment was 1.11 (95% confidence interval 0.71-1.73; P = 0.64).

CONCLUSION

This study fails to show an advantage of one treatment arm over the other, but a trend, albeit non-significant, appears to favor the sequential addition of tamoxifen to epirubicin + cyclophosphamide and, as such, warrants further investigation.

Functionally active duplications of the CYP2D6 gene are more prevalent among larynx and lung cancer patients

The cytochrome P450 CYP2D6 is a polymorphic drug-metabolizing enzyme that is involved in the metabolism of several drugs and xenobiotics. Several independent studies indicate that the CYP2D6 metabolic status is a secondary factor in the risk of developing lung cancer, with individuals with high activity being at increased risk. The occurrence of functionally active duplications of the CYP2D6 gene is a phenomenon that affects 3-8% of Caucasians and up to 30% in some ethnic groups. These duplications cause ultrarapid metabolism of CYP2D6 substrates. In order to establish whether the highest CYP2D6 enzyme activity is associated with an increased risk of cancer, we analyzed the frequency of CYP2D6 gene duplications and enzyme-inactivating mutations in 199 Caucasian patients with lung or larynx cancer and in 335 healthy controls. A significantly increased frequency of carriers of the CYP2D6 gene duplication were found among lung and larynx cancer patients (13%), as compared with healthy controls (6.9%; p < 0.02). The frequency of the mutated active CYP2D6*9 allele was increased in lung cancer patients (p < 0.01) but not in larynx cancer patients. Global findings indicate that over 20% patients with lung or larynx cancer show CYP2D6 genotypes leading to ultrarapid metabolism or to the expression of an enzyme with altered kinetics (p < 0.01 vs. healthy controls). This may influence the metabolism of CYP2D6 substrates, including antineoplastic drugs and opioid derivatives used for pain relief in cancer patients. These patients would require higher doses than those considered as standard. We conclude that dosages for CYP2D6 substrates should be adapted to lung and larynx cancer patients.

Preliminary results. UFT/methotrexate/leucovorin for breast Ca patients in progression after HDCT/PBPC support

Twenty-four patients with metastatic breast cancer that had progressed after high-dose chemotherapy with peripheral blood progenitor cell (PBPC) support were given intramuscular methotrexate in combination with oral UFT (tegafur and uracil) and oral leucovorin (the MUL regimen). Of the total treated, 21 patients are currently evaluable for response and toxicity. All patients had received extensive prior chemotherapy, including a high-dose regimen with PBPC support. Of the 21 assessable patients, 8 obtained either a complete response (1) or partial response (7), for an overall objective response rate of 38%. Another 7 patients had stable disease for 3 or more months. Therefore, the MUL regimen was able to stop disease progression for 3 or more months in nearly 75% of patients. The median time to progression and median overall survival from the start of MUL were 6 and 9 months, respectively. The toxicity was mainly gastrointestinal; 6 patients (29%) had World Health Organization grade 2/3 diarrhea, leading to a UFT dose reduction. Emesis was mild and easily manageable with thiethylperazine. In conclusion, MUL chemotherapy is active and well tolerated in patients with metastatic breast cancer in progression after high-dose chemotherapy. Further studies with this regimen, either as salvage chemotherapy or as maintenance chemotherapy after high-dose chemotherapy with PBPC, are warranted.

Increased risk for hepatocellular carcinoma in NAT2-slow acetylators and CYP2D6-rapid metabolizers

The arylamine N-acetyltransferase (NAT2) is a polymorphic enzyme which is expressed in the liver in a genotype-determined manner. NAT2 is involved in activation and inactivation of carcinogens through N-acetylation. We studied the role of this polymorphism in the development of hepatocellular carcinoma (HCC). One hundred consecutive patients diagnosed for HCC and 258 healthy volunteers were studied for NAT2 genotype. The occurrence of seven enzyme-inactivating and silent point mutations in the coding region of the NAT2 gene was studied by mutation-specific PCR amplification. An excess of subjects homozygous for NAT2 loss of function alleles was observed among patients with HCC (68% vs 53.9% controls). The relationship between the slow acetylator NAT2 genotype and HCC risk is more pronounced in patients lacking serum HBV and HCV markers. The additional determination of alleles of the cytochrome P450 2D6 (CYP2D6) gene in the same subjects confirmed our previous findings that subjects with two active CYP2D6 genes are at increased risk of developing HCC. The genetic polymorphism of NAT2 is a relevant factor in the risk for developing HCC (inverse odds ratio slow vs rapid = 1.8; 95% CI 1.1-3.0). The inverse odds ratio for subjects with two risk genotypes (two defect NAT2 genes and two or more active CYP2D6 genes) is 2.6 (95% CI 1.6-4.4) for all patients with HCC, and 5.6 (95% CI 1.4-33.3) for patients without serum viral markers.

Acute and anticipatory emesis in breast cancer patients

A group of 90 breast cancer patients undergoing chemotherapy were assessed prospectively to estimate the prevalence of acute (post-treatment) and anticipatory emesis in the 1990s. For this purpose, two protocols of chemotherapy were analysed separately: cyclophosphamide/methotrexate/5-fluorouracil (CMF) and 5-fluorouracil/doxorubicin/cyclophosphamide (FAC). All patients were treated with antiemetic therapy, which included one corticoid plus ondansetron (in the FAC regimen), or one corticoid plus thiethylperazine (in the CMF regimen). For at least one cycle of chemotherapy 86.1% and 91.7% patients in the FAC protocol presented vomiting and nausea respectively: 11.1% had anticipatory vomiting and 30.6% had anticipatory nausea. In the CMF protocol, 79.6% had post-chemotherapy vomiting and 71.7% had post-chemotherapy nausea associated with at least one cycle. In this group, 7.4% had anticipatory vomiting and 16.6% had anticipatory nausea. A high proportion of patients suffered anticipatory anxiety in both groups (75% in FAC, 74.1% in CMF). The stimuli most frequently associated with the appearance of anticipatory emesis were olfactory stimuli and cognitive stimuli. In summary, as a result of the advances made in antiemetic control during the last decade, the severity of chemotherapy-induced emesis seems to have significantly decreased, but the prevalence of these symptoms along the course of the treatment still remains high.

Clinical activity of chronic oral etoposide in previously treated metastatic breast cancer

PURPOSE

This study was undertaken to assess the antitumor activity and tolerance of chronic oral etoposide (50 mg/m2/d for 21 days every 4 weeks) in metastatic breast cancer (MBC).

PATIENTS AND METHODS

Forty-three consecutive metastatic breast cancer patients with at least one site of measurable disease entered the study. All patients had received prior chemotherapy (adjuvant, three patients; adjuvant plus chemotherapy for metastases, 21; chemotherapy for metastases, 19). Twenty-two and 21 patients had also received prior hormonal and radiation therapy, respectively.

RESULTS

Thirty-five percent of patients (15 of 43; 95% confidence interval, 21% to 51%) had objective responses, according to an intention-to-treat analysis. Responses were seen in lymph nodes (six of 14), skin and soft tissues (eight of 16), lung (six of 14), lytic lesions of the bone (two of six), liver (four of 23), and peritoneum (one of one). The median duration of response was 7 months (range, 3+ to 12). The main toxic side effects were leukopenia (overall, 65% of patients; World Health Organization [WHO] grade 4, 21%), thrombocytopenia (21%; WHO grade 4, 5%) and anemia (51%; WHO grade 4, 5%). Nine patients (21%) required a 25% dose reduction because of myelosuppression, and one patient abandoned treatment because of gastrointestinal toxicity and severe asthenia. Ninety-one percent of patients developed alopecia, 39.5% had mucositis (WHO grade 3, 9.5%) and 60.5% had some degree of emesis (11.5% nausea, 46.5% transient vomiting, 2.5% intractable vomiting). No toxic deaths occurred.

CONCLUSION

Chronic oral etoposide appears to be an active and well-tolerated regimen in MBC patients previously exposed to chemotherapy. This schedule of etoposide administration warrants further studies, alone or in combination, in MBC.