Abstract OT1-10-01: Treatment with Tucatinib in addition to Pertuzumab and Trastuzumab in patients with HER2-positive metastatic breast cancer (HER2+ MBC) after local therapy of isolated brain progression: InTTercePT, a UCBG/GINECO study

Treatment with Tucatinib in addition to Pertuzumab and Trastuzumab in patients with HER2-positive metastatic breast cancer (HER2+ MBC) after local therapy of isolated brain progression: InTTercePT, a UCBG/GINECO study. Background HER2+ MBC patient on first line treatment with pertuzumab and trastuzumab have a 13% risk of developing brain metastasis (BM) as the first site of progression. For such patient with isolated brain progression, guidelines recommend to use central nervous system (CNS) directed therapy whenever possible (stereotactic radiosurgery or surgery or both). These patients will have a higher risk of subsequent brain and systemic progression after local treatment. Therefore, whether systemic treatment should be continued or changed remains an open question. The tyrosine kinase inhibitor tucatinib is an orally bioavailable HER2 inhibitor with validated antineoplastic activity and the ability to cross the blood brain barrier. The randomized HER2CLIMB study, demonstrated that adding tucatinib to trastuzumab/capecitabine improved both progression-free survival (PFS) and overall survival (OS) among HER2+ MBC patients previously treated with trastuzumab, pertuzumab and T-DM1. Particularly, this regimen demonstrated improved antitumor activity in patients with BM, in terms of CNS-PFS and OS. Exploratory analysis of HER2CLIMB and in a phase 1b study, showed patients who continued systemic treatment with tucatinib (in combination either with trastuzumab/capecitabine or TDM-1) after CNS-directed treatment had a better outcome compared with those that discontinued systemic tucatinib-based treatment. These results suggest that for patient in the first line metastatic setting who experience isolated brain progression, adding tucatinib to the trastuzumab/pertuzumab regimen could help control BM, improve PFS, OS and patients’ quality of life. Trial design InTTercePT is an open-label, single-arm, national, multicentric, phase II trial assessing the combination of tucatinib, pertuzumab and trastuzumab. Tucatinib will be administered orally twice daily at 300 mg. Pertuzumab and trastuzumab will be administered at the initial dose of 840 mg and 8 mg/kg respectively following by a maintenance dose of 420 mg and 6mg/kg respectively, 3-weekly. If indicated, hormone therapy is allowed in combination with HER2-directed therapy. Eligibility criteria include HER2+ MBC with isolated brain progression (new or progressive BM with stable or responding systemic disease) under pertuzumab/trastuzumab treatment (± taxane) after complete local treatment (surgery and/or radiation therapy). There is no limit to the number and size of BM. Specific aims To evaluate the efficacy, in terms of PFS rate (RECIST v1.1) of tucatinib in combination with pertuzumab/trastuzumab. Secondary endpoints include OS, brain PFS (RECIST v1.1) and BM response in patient not in complete remission at the brain level after local treatment and safety (NCI-CTCAE v5.0). Statistical methods Given the lack of safety data from this association, two interim safety analysis are planned: after 10 and 20 patients having received at least one dose of the treatments combination during at least one cycle. The number of patients to be included was calculated using Fleming’s single-stage procedure for phase II trials. The sample size calculation was based on a minimum success (non-progression rate at 6 months) considered of interest of p1 = 75% and an uninteresting rate of p0 = 60%. Assuming a unilateral type I error alpha of 10% and a power of 85%, 52 patients are needed. Considering 5% of the patients may be non-evaluable, 55 patients will be included. At the time of analysis, if at least 37 successes are observed, the treatment will be considered as interesting for further investigation. The study is recruiting. By July 1, 2022, 10 patients have been screened and 8 treated (NCT05041842). Funding SeaGen Contact information thomas.bachelot@lyon.unicancer.fr

Citation Format: Thomas Bachelot, Christelle Jouannaud, Benjamin Verret, Sylvie Chabaud, Camille Petrau, Laetitia Stefani, Mony Ung, Isabelle Desmoulins, William Jacot, Caroline Bailleux, Sandrine Marques, Jérôme Lemonnier, Anne-Claire Hardy-Bessard. Treatment with Tucatinib in addition to Pertuzumab and Trastuzumab in patients with HER2-positive metastatic breast cancer (HER2+ MBC) after local therapy of isolated brain progression: InTTercePT, a UCBG/GINECO study [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr OT1-10-01.

Factors associated with non-completion of radiation therapy (RT) or radiochemotherapy (RTCT) in head and neck squamous cell carcinoma (HNSCC): A prospective study

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Background: Although numerous factors have been reported to increase RT/RTCT toxicity, identification of patients with high risk of toxicities is lacking. Methods: The monocentric NutriNeck study (NCT02900963) recruited all HNSCC patients between 2014 and 2018 treated by RT or RTCT. Patients fed by enteral nutrition before RT initiation were excluded. All clinical and biological, planned RT or RTCT parameters were collected at baseline. A daily monitoring of the weight and a weekly evaluation of clinical, biological and food intake during RT/RTCT were performed. A nutritional intervention by enteral feeding was systematically proposed in case of 2 kg weight loss under treatment. Complete treatment was defined as full planned RT doses without more than 3 days interruption, and full planned doses of cisplatin and cetuximab if indicated. Primary endpoint assessed factors associated with non-completion of the planned treatment. Secondary endpoint assessed factors associated with use of enteral nutrition during treatment. A p value < 0.01 was considered significant. Results: Among the 249 HNSCC patients included, 118 (47%) were treated by RT and 131 (53%) by RTCT. 63 patients (25%) did not complete treatment: 3/118 (2.5%) in the RT group compared to 60/131 (45.8%) the RTCT group, p < 0.0001. Median weight lost during treatment (7 vs 3.8 kg, p < 0.0001) and grade 3 toxicities (53 vs 33%, p = 0.006) were more frequent in patients with incomplete RT/RTCT. Nutritional intervention was performed in 111 patients: 28 (23.7%) with RT and 83 (62.6%) with RTCT (p < 0.0001). Week 4 was associated with the higher rate of enteral nutrition initiation in both RT and RTCT groups. Among RTCT group, weight loss during treatment (OR 1.2 for each kg, p < 0.0001) and use of enteral feeding (OR 2.7, p = 0.005) were associated with incomplete treatment in multivariate analysis. Of note, 48 patients refused enteral nutrition while indicated, they had comparable grade 3 toxicities and weight loss during treatment compared to the 111 patients who accepted enteral nutrition. Conclusions: Incomplete treatment is overwhelmingly associated with RTCT rather than RT. Baseline clinical, biological features or treatment volume/dose are not associated with incomplete treatment. Enteral nutrition initiated during treatment is poorly efficient.

Kinetics, prognostic and predictive values of ESR1 circulating mutations in metastatic breast cancer patients progressing on aromatase inhibitor

Purpose

To assess the prognostic and predictive value of circulating ESR1 mutation and its kinetics before and after progression on aromatase inhibitor (AI) treatment.

Patients and methods

ESR1 circulating D538G and Y537S/N/C mutations were retrospectively analyzed by digital droplet PCR after first-line AI failure in patients treated consecutively from 2010 to 2012 for hormone receptor-positive metastatic breast cancer. Progression-free survival (PFS) and overall survival (OS) were analyzed according to circulating mutational status and subsequent lines of treatment. The kinetics of ESR1 mutation before (3 and 6 months) and after (3 months) AI progression were determined in the available archive plasmas.

Results

Circulating ESR1 mutations were found at AI progression in 44/144 patients included (30.6%). Median follow-up from AI initiation was 40 months (range 4-94). The median OS was decreased in patients with circulating ESR1 mutation than in patients without mutation (15.5 versus 23.8 months, P=0.0006). The median PFS was also significantly decreased in patients with ESR1 mutation than in patients without mutation (5.9 vs 7 months, P=0.002). After AI failure, there was no difference in outcome for patients receiving chemotherapy (n = 58) versus non-AI endocrine therapy (n=51) in patients with and without ESR1 mutation. ESR1 circulating mutations were detectable in 75% of all cases before AI progression, whereas the kinetics 3 months after progression did not correlate with outcome.

Conclusion

ESR1 circulating mutations are independent risk factors for poor outcome after AI failure, and are frequently detectable before clinical progression. Interventional studies based on ESR1 circulating status are warranted.

Reliability of Prognostic and Predictive Factors Evaluated by Needle Core Biopsies of Large Breast Invasive Tumors

OBJECTIVES

Preoperative biopsy of breast cancer allows for prognostic/predictive marker assessment. However, large tumors, which are the main candidates for preoperative chemotherapy, are potentially more heterogeneous than smaller ones, which questions the reliability of histologic analyses of needle core biopsy (NCB) specimens compared with whole surgical specimens (WSS). We studied the histologic concordance between NCB specimens and WSS in tumors larger than 2 cm.

METHODS

Early pT2 or higher breast cancers diagnosed between 2008 and 2011 in our center, with no preoperative treatments, were retrospectively screened. We assessed the main prognostic and predictive validated parameters. Comparisons were performed using the κ test.

RESULTS

In total, 163 matched NCB specimens and WSS were analyzed. The correlation was excellent for ER and HER2 (κ = 0.94 and 0.91, respectively), moderate for PR (κ = 0.79) and histologic type (κ = 0.74), weak for Ki-67 (κ = 0.55), and minimal for SBR grade (κ = 0.29). Three of the 21 HER2-positive cases (14% of HER2-positive patients or 1.8% of all patients), by WSS analysis, were initially negative on NCB specimens even after chromogenic in situ hybridization.

CONCLUSIONS

NCB for large breast tumors allowed reliable determination of ER/PR expression. However, the SBR grade may be deeply underestimated, and false-negative evaluation of the HER2 status would have led to a detrimental lack of trastuzumab administration.

CD70: A Potential Target in Breast Cancer?

CD70 is a co-stimulatory molecule involved in the immune response and also in cancer development and progression. Recent studies show that high CD70 expression in cancer cells may inhibit the anti-tumor response. Furthermore, CD70 expression has been reported as a predictive marker of resistance to chemotherapy in ovarian cancers. Some in vitro studies have shown that CD70 expression is epigenetically down-regulated through hypermethylation of its promoter during tumoral progression. This study evaluated the level of CD70 expression in surgical samples of breast invasive tumors and determined its correlation with CD70 promoter methylation.

Twenty “luminal A” and 20 “basal-like” frozen samples from early breast tumors were retrospectively selected. CD70 expression was evaluated by quantitative real-time PCR. Total DNA was bisulfite-treated, and methylation levels of 5 consecutive CG sites present in the proximal region (-464, -421) of the promoter were assessed by pyrosequencing analysis. Statistical analyses were performed using the Mann-Whitney test.

The median relative CD70 expression level was 0.37 and was significantly higher in the basal-like group (0.78 [0.24-31.7]) compared to the luminal A group (0.25 [0.03-1.83], p=0.0001). The median methylation level was 61%, with no significant difference between the basal-like (63%) and luminal A (58%) groups. No correlation was found between CD70 expression and CD70 methylation level.

In this study, higher CD70 expression was observed in the basal-like group, but this expression was not related to promoter methylation. The higher expression in the poor-prognosis subgroup of patients makes CD70 a potential target for emerging anti-CD70 therapies.

Reliability of prognostic and predictive factors evaluated by needle core biopsy for breast cancer in large tumors

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Background: Preoperative needle core biopsy (NCB) in breast cancer allows both invasive carcinoma diagnosis and the assessment of the main prognostic/predictive markers. However, large tumors, which may be candidates for preoperative chemotherapy, are potentially more heterogeneous than small ones, and the reliability of these factors measurements by NCB in these cases has been less documented than in whole surgical specimens (SS). The aim of this study was to evaluate the correlation for the main histological and immunohistochemical (IHC) features between NCB and SS in large tumors (>2cm), and to assess major discordances that may impact the therapeutic decisions. Methods: All patients treated in our center for newly diagnosed early breast cancer between January 2008 and December 2011 were retrospectively screened. Large tumors for which both NCB and SS were available were included. Patients treated by preoperative chemotherapy were excluded. The assessed histological and IHC parameters were histological type, SBR grade, estrogen (ER) and progesterone receptors (PR) expression, HER2 status (completed by CISH if needed), intrinsic subtype, and proliferation markers (mitotic activity index (MAI), Ki67). All samples were independently read twice. Comparisons were performed using Kappa test. Results: 163 pairs of NCB-SS were analyzed. Average pathological tumor size was 3.2cm. Correlation was excellent for ER and HER2 (k=0.98 and 0.91 respectively), good for histological type (k=0.74), PR (k=0.79) and intrinsic subtype (k=0.73), but poor for Ki67 (k=0,60), SBR grade (k=0.29) and MAI (k=0.24). Among major discordances, 6 tumors were graded SBR I on NCB but SBR III on SS; 1 tumor was negative for ER on NCB but positive on SS. Importantly, 3 of the 21 HER2 positive cases (14%) were negative after CISH on NCB but positive on SS. Conclusions: Diagnostic NCB in large early breast tumors allows reliable determination of hormonal receptors expression, histological type and intrinsic subtype. SBR grade may however be deeply underestimated by this method, and false negative evaluation of the HER2 status in 14% of HER2 positive patients would have led to a detrimental lack of trastuzumab administration.