Abstract P2-04-01: Increased stromal lymphocytes in breast cancer patients with autologous dendritic cell vaccination plus neoadjuvant chemotherapy

Introduction: Higher levels of TILs after neoadjuvant chemotherapy (NAC) in the residual tumor have been related to a better outcome in BC patients. According to International TILs working group (2014), we have quantified stromal TILs in a cohort of patients treated with NAC plus dendritic cell vaccines (cohort V) (NCT01431196 plus an expanded cohort) and in an historic cohort of patients treated with the same NAC without V (cohort C) in order to assess if the addition autologous dendritic cell vaccination pulsed with patient´s tumor lysates helps to increase TILs in the residual BC specimen. Our previous data with these cohorts of patients have shown an improved pCR and the stimulation of lymphocytes population in the peripheral blood from cohort V.

Methods: Classification of molecular subtypes was performed by IHC. We evaluated percentage of TILs by three different pathologists using stained HE core biopsy sections in paired samples taken at diagnosis (preNAC) and after surgery (postNAC) in a prospectively defined retrospective analysis.

Results: 79 patients were evaluated (cohort C 42; cohort V 37). Patients from V cohort were younger (p=0.01). Cohorts were well balanced for AJCC staging, molecular subtypes (cohort C: LA 26%, LB 45%, TN 29%; cohort V: LA 24%, LB 40%, TN 35%), stromal TILs preNAC [cohort C: median 9 (range, 1-24); cohort V: 6 (1-34); p=0.38] and stromal TILs postNAC [cohort C: 9 (2-52); cohort V 8 (4-50); p=0. 94]. Seventy-seven patients (97%) underwent surgery (cohort C 41; cohort V 36). Pathologic CR was higher in Cohort V (27% vs 7%; p=0.02). However a superior pCR rate was detected in TNBC subtype (cohort C 27%; cohort V 58%; p=0.15). Patients from Cohort V experienced an increment of stromal TILs after NAC plus autologous dendritic cell vaccination (preNAC: 6 (1-34); postNAC 8 (4-50); p=0.03), especially in TNBC [preNAC 14 (1-34); postNAC 30 (10-50); p=0.2]. A correlation analysis by Pearson´s R coefficient stated a strong association in V cohort between stromal TILs preNAC and postNAC (R=0.83) as well as a moderate correlation between stromal TILs postNAC and and molecular subtypes (R=0.6).

Table 1. Differences in Stromal TILs between studied cohorts PreNAC (median, range)PostNAC (median, range)P valueCohort C9 (1-66)9 (2-52)0.22Cohort V6 (1-34)8 (4-50)0.03*Cohort C LA LB TN5 (1-10) 9 (1-24) 12 (10-24)6 (3-12) 10 (2-40) 13 (5-52)0.69 0.17 1Cohort V LA LB TN5 (2-17) 6 (1-15) 14 (1-347 (4-12) 7 (4-27) 30 (10-50)0.18 0.08 0.2

Conclusion: Pathological complete responses were higher in BC patients treated with neoadjuvant chemotherapy plus active immunotherapy. The addition of autologous dendritic cell vaccines to NAC increases significantly stromal TILs in breast cancer patients.

Citation Format: Baraibar I, Martin-Romano P, Mejías L, Perez Solans B, Ceniceros L, Legazpi J, Gardeazabal I, Inoges S, Lopez-diaz A, Idoate M, Cordoba A, Santisteban M. Increased stromal lymphocytes in breast cancer patients with autologous dendritic cell vaccination plus neoadjuvant chemotherapy [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 P2-04-01.

Idiotype vaccines for human B-cell malignancies

After twenty years of use in humans, customized idiotypic vaccination yet remains a non-approved, experimental therapeutic option for patients with lymphoma and myeloma. Potentially applicable to all B-cell malignancies whose cells express a clonal immunoglobulin or its epitopes on their surface, this treatment is designed to prevent disease recurrence or progression. Mostly used in follicular lymphoma patients so far, idiotype vaccines have clearly shown biological efficacy, clinical efficacy and clinical benefit in this setting, although no study aiming at regulatory approval of the procedure has been able to meet its main clinical endpoints. In mantle cell lymphoma, only biological efficacy has been proven for idiotypic vaccination, while in multiple myeloma a limited number of studies support the notion of biological and perhaps even clinical efficacy, although no credible evidence of clinical benefit has still emerged. Idiotype vaccines have been produced and administered in a number of substantially different manners. Therefore, the results of most clinical trials cannot be easily compared, and even less pooled together in meaningful meta-analyses. A more creative and yet scientifically sound way to design clinical trials of customized active immunotherapies will be key to the future development of idiotype vaccines, particularly considering that we currently lack any clinical or biological indicator to possibly predict which patients are more likely to respond to idiotypic vaccination from an immunologic point of view. This review aims at summarizing the multifaceted success achieved by idiotype vaccines, as well as at outlining the challenges awaiting them in the near future: how to improve feasibility, immunogenicity and efficacy, as well as how to confirm benefit and gain regulatory approval.

Expression and serum levels of MMP-2 and MMP-9 during human melanoma progression

Matrix metalloproteinases (MMP)-2 and -9 have been implicated in malignant tumour progression, partly because they degrade collagen type IV, a major component of basement membranes. Biopsy specimens from 56 patients with primary melanoma and 7 with cutaneous or nodal metastases were studied by immunohistochemistry. Of 39 patients with estimated good prognosis, 70.5% of melanomas were negative for MMP-2, compared with only 47% of 17 melanomas in patients who developed metastasis during the 3-year follow-up. All skin and nodal metastases were negative for MMP-2 and positive for MMP-9. Of 14 thick melanomas, 9 were mostly positive for MMP-2 expression, suggesting a possible association with the invasiveness of the melanoma. MMP-2 and MMP-9 plasma levels were analysed in another 29 patients with melanoma (10 stage I and II, 9 stage III, and 10 stage IV) and in 10 healthy controls. No difference in MMP-9 plasma levels was found among the groups. Higher MMP-2 concentrations were observed in patients with metastatic disease (stage IV) than in those with primary melanoma (stage I) or in controls. Serial levels in two patients who passed from stage I to stage III or IV showed no significant difference in MMP-2 or -9 values. We conclude that MMP-2 expression might be associated with progression of the melanoma. Circulating MMP-2 and -9 levels have shown low sensitivity and specificity, so they do not seem to be good tumour markers in patients with melanoma.