Antinuclear antibodies may predict the development of immune-related adverse events in asymptomatic patients treated with immune checkpoint inhibitors: results from a single-center cohort

We aim at investigating the association between subclinical autoimmunity and immune-related adverse events (irAEs) in a cohort of patients treated by immune checkpoint inhibitors for solid metastatic cancer. In the context of an oncology/rheumatology outpatient clinic, we evaluated patients treated with anti-PD-1 or anti-PD-L1. Before treatment, each patient underwent a physical evaluation and a blood sample to identify the presence of a set of autoantibodies. Indeed, all the patients were followed during treatment to identify irAEs and to assess the association with autoantibodies. Fifty-one patients (M/F 16/35; median age 70 years, IQR 16.5) were evaluated; 34.8% of patients showed ANA positivity, 6.5% ENA positivity (anti-SSA), 4.3% Ratest positivity, and 2.1% (one patient) ACPA positivity. During a median period of 21 months (IQR 38.75), 39.2% of patients developed irAEs. Musculo-skeletal manifestations, in particular arthritis, were the most frequent. We found a significant association between the positivity for ANA and the development of irAES (p = 0.03, RR 2.01, 95% CI 1.03-3.92). Furthermore, the progression-free survival was significantly longer in patients developing irAEs compared to those who are not experiencing these events (p = 0.007). This study underlines the potential role of ANA positivity as a predictive biomarker for the development of irAEs.

Real-World Outcomes of Trastuzumab Deruxtecan in Patients With HER2+ Metastatic Breast Cancer: The DE-REAL Study

BACKGROUND

Trastuzumab deruxtecan (T-DXd) demonstrated unprecedented efficacy in patients with pretreated HER2+ metastatic breast cancer (mBC). However, few data are available about its efficacy in routine clinical practice. In this multicenter retrospective study, we examined effectiveness and safety of T-DXd in a real-world population.

METHODS

Clinico-pathological information about patients with HER2+ mBC who received T-DXd were collected from 12 Italian hospitals. HER2 status was determined locally. Patients who received at least one administration of T-DXd, as any therapy line for advanced disease were included in the analysis. The primary endpoint was real-word PFS (rwPFS).

RESULTS

One hundred and forty-three patients were included. Median age was 66 (range: 37-90), and 4 men were included. Hormone receptor (HR) status was positive in 108 (75%) patients and negative in 35(25%). T-DXd was administered as first, second, third, or subsequent lines in 4 (3%), 16 (11%), 42 (29%), and 81 (57%) patients, respectively. Among 123 patients with measurable disease, the ORR was 68%, and the DCR was 93% (9 CRs, 74 PRs, and 30 SD). Nine (7%) patients had a primary resistance to T-DXd. With a median follow-up of 12 months, the median rwPFS was 16 months. RwPFS was 84%, 59%, and 39% at 6, 12, and 18 months, respectively. A favorable trend in rwPFS was reported in patients receiving T-DXd as I/II line versus further lines (17 vs. 15 months; P = .098). Any-grade toxicity was registered in 84 patients (59%). Most common adverse events (AEs) reported were nausea (33%), neutropenia (21%), and asthenia (21%). Liver toxicity and diarrhea were uncommon (5% and 1%). Severe toxicities was registered in 18% of patients, and the most frequent were neutropenia, nausea/vomiting, and ILD observed in 15, 2, and 3 patients. AEs led to dose reduction in 37 patients (26%). Dose reduction and AEs do not affect patients' response and survival outcomes.

CONCLUSIONS

Efficacy and safety of T-DXd were confirmed in an unselected real-world population of HER2+ mBC. These results are consistent with the results of known findings, and no new safety concerns were reported.

PD-L1 testing in metastatic triple negative breast cancer: Results of an Italian survey

BACKGROUND

Immunotherapy has revolutionized the approach to metastatic triple-negative breast cancers. Atezolizumab was approved for patients with metastatic triple-negative breast cancers whose tumors express PD-L1, determined by SP 142 assay. To assess the availability and practice of SP142 test we administered a survey to all the 15 pathology departments of the Lazio Region during a six-month period.

METHODS

The survey comprised 12 questions regarding the availability of SP142 in the pathology departments, the percentage of positive tests, the difficulties of pathologists in cases close to cut-off value and the tested samples.

RESULTS

The SP142 assay was available in only eight centers. In case of positive result, most centers (5/8, 62.5%) reported values of PD-L1 expression ranging from > 1 to ⩽ 5%, with values close to the cut-off point (⩾ 1% or < 1%) being the greatest challenge.Most of the centers (6/8, 75%) tested material from both their own and other hospitals. In most centers, the evaluations were performed either on primary tumors or metastasis, in particular lymph nodes (5/8, 62.5%), followed by lung (3/8, 37.5%) and liver (1/8, 12.5%) metastasis.

CONCLUSION

Our results raise some important issues concerning the evaluation of PD-L1 in the "real-life" setting, providing strategies for its implementation.

Immune responses and clinical outcomes following the third dose of SARS-CoV-2 mRNA-BNT162b2 vaccine in advanced breast cancer patients receiving targeted therapies: a prospective study

Purpose

Metastatic breast cancer patients are the most prevalent oncology population with advanced disease facing COVID-19 pandemic. Immune responses after mRNA-based vaccination during treatment with CDK4/6 inhibitors or HER2-directed agents remain unclear. We conducted a prospective analysis to elucidate changes in antibody titers and lymphocyte counts following full course of mRNA-BNT162b2 (tozinameran) vaccination in recipients undergoing these targeted therapies.

Methods

Patients who had received a booster dosing and had been treated for at least 6 months were eligible. Antibody titers against SARS-CoV-2 spike protein were measured at four subsequent time points. Immunophenotyping of circulating lymphocytes was performed before the third dose of tozinameran and four weeks later to quantify the absolute counts of CD3+CD4+ T-helper cells, CD3+CD8+ T-cytotoxic cells, CD19+ B cells, and CD56+CD16+ NK cells. We also assessed the incidence of breakthrough infections and investigated whether immune changes affect time-to-treatment failure (TTF) after booster vaccination.

Results

The current analysis included 69 patients, of whom 38 (55%) and 31 (45%) were being treated with CDK4/6 inhibitors and HER2-targeted therapies, respectively. All participants received a third dose of tozinameran between September 23 and October 7, 2021. Multivariate analysis revealed that CDK4/6 inhibition predicted a significantly impaired humoral response after the booster dose. This detrimental effect was also evident for T-helper cell counts before the third immunization, but it disappeared in the subsequent evaluation. After a median follow-up of 22.3 months, we observed 19 (26%) cases of COVID-19 outbreaks, all experiencing favorable clinical outcomes. Univariate analysis showed a significant association between the onset of SARS-CoV-2 infections and the use of CDK4/6 inhibitors, as well as with an impaired antibody and T-helper cell response. Only the last two covariates remained independent predictors after multivariate testing. Dynamic variations in antibody titers and T-helper cell counts did not affect TTF in multivariate regression analysis.

Conclusions

Our results confirm that the immune response to tozinameran is impaired by CDK4/6 inhibitors, increasing the odds of breakthrough infections despite the third vaccine dose. Current evidence recommends maintaining efforts to provide booster immunizations to the most vulnerable cancer patients, including those with advanced breast cancer undergoing CDK4/6 inhibition.

The Impact of Drug-Drug Interactions on the Toxicity Profile of Combined Treatment with BRAF and MEK Inhibitors in Patients with BRAF-Mutated Metastatic Melanoma

BACKGROUND

BRAF and MEK inhibition is a successful strategy in managing BRAF-mutant melanoma, even if the treatment-related toxicity is substantial. We analyzed the role of drug-drug interactions (DDI) on the toxicity profile of anti-BRAF/anti-MEK therapy.

METHODS

In this multicenter, observational, and retrospective study, DDIs were assessed using Drug-PIN software (V 2/23). The association between the Drug-PIN continuous score or the Drug-PIN traffic light and the occurrence of treatment-related toxicities and oncological outcomes was evaluated.

RESULTS

In total, 177 patients with advanced BRAF-mutated melanoma undergoing BRAF/MEK targeted therapy were included. All grade toxicity was registered in 79% of patients. Cardiovascular toxicities occurred in 31 patients (17.5%). Further, 94 (55.9%) patients had comorbidities requiring specific pharmacological treatments. The median Drug-PIN score significantly increased when the target combination was added to the patient's home therapy (p-value < 0.0001). Cardiovascular toxicity was significantly associated with the Drug-PIN score (p-value = 0.048). The Drug-PIN traffic light (p = 0.00821) and the Drug-PIN score (p = 0.0291) were seen to be significant predictors of cardiotoxicity. Patients with low-grade vs. high-grade interactions showed a better prognosis regarding overall survival (OS) (p = 0.0045) and progression-free survival (PFS) (p = 0.012). The survival analysis of the subgroup of patients with cardiological toxicity demonstrated that patients with low-grade vs. high-grade DDIs had better outcomes in terms of OS (p = 0.0012) and a trend toward significance in PFS (p = 0.068).

CONCLUSIONS

DDIs emerged as a critical issue for the risk of treatment-related cardiovascular toxicity. Our findings support the utility of DDI assessment in melanoma patients treated with BRAF/MEK inhibitors.

[Management of the patient with extensive stage microcytoma. The importance of collaboration between oncology and radiotherapy.]

Small cell lung cancer (SCLC) represents one of the most complex challenges in the oncological field, with a very slow advancement in research, contrary to the rapid evolutionary of the disease. For nearly two years, the mainstay of treatment for extensive-stage disease (ES-SCLC) has been the combination of platinum-based chemotherapy and immunotherapy, following the approval of atezolizumab and subsequently durvalumab, based on a modest, but significant improvement in overall survival compared to chemotherapy alone. The poor prognosis after the failure of first-line treatment explains the need to maximize the duration and efficacy of up-front systemic therapies, in particular, the emerging role of radiotherapy, also in ES-SCLC. On 10 November 2022, a meeting concerning the integrated treatment of patients with ES-SCLC was held in Rome and was attended by 12 specialists in oncology and radiotherapy from various centers in Lazio, under the direction of Federico Cappuzzo, Emilio Bria and Sara Ramella. The aim of the meeting was to share their clinical experience and to provide a series of practical indications in order to support physicians in the correct integration between first-line chemo-immunotherapy and radiotherapy treatments in ES-SCLC.

Pathologic response and survival after neoadjuvant chemotherapy with or without pertuzumab in patients with HER2-positive breast cancer: the Neopearl nationwide collaborative study

Purpose

Clinical trials have shown a significant increase in pathologic complete response (pCR) with the addition of pertuzumab to neoadjuvant chemotherapy for patients with early-stage HER-2 positive breast cancer. To date, limited studies have examined comparative outcomes of neoadjuvant pertuzumab in real-world setting. The Neopearl study aimed to assess comparative real-life efficacy and safety of neoadjuvant pertuzumab for these patients.

Methods

We conducted a nationwide retrospective analysis involving 17 oncology facilities with a certified multidisciplinary breast cancer treatment committee. We identified patients with HER-2 positive stage II-III breast cancer treated with neoadjuvant chemotherapy based on trastuzumab and taxanes with or without pertuzumab. All patients underwent breast surgery and received a comprehensive cardiologic evaluation at baseline and after neoadjuvant treatment. Patients who received the combination of pertuzumab, trastuzumab, and chemotherapy constituted case cohort (PTCT), whereas those treated with trastuzumab and chemotherapy accounted for control cohort (TCT). The pCR rate and 5-year event free survival (EFS) were the primary outcomes. Secondary end-points were rates of conversion from planned modified radical mastectomy (MRM) to breast conservation surgery (BCS) and cardiotoxicities.

Results

From March 2014 to April 2021, we included 271 patients, 134 (49%) and 137 (51%) in TCT and PTCT cohort, respectively. Positive axillary lymph nodes and stage III were more frequent in PTCT cohort. The pCR rate was significantly increased in patients who received pertuzumab (49% vs 62%; OR 1.74, 95%CI 1.04-2.89) and with HER-2 enriched subtypes (16% vs 85%; OR 2.94, 95%CI 1.60-5.41). After a median follow-up of 5 years, the 5-year EFS was significantly prolonged only in patients treated with pertuzumab (81% vs 93%; HR 2.22, 95%CI 1.03-4.79). The same analysis performed on propensity score matched population showed concordant results. On univariate analysis, only patients with positive lymph nodes were found to benefit from pertuzumab for both pCR and 5-year EFS. The rates of conversion from MRM to BCS and cardiologic toxicities did not differ between the cohorts.

Conclusion

Our findings support previous data on improved outcomes with the addition of pertuzumab to trastuzumab-based neoadjuvant chemotherapy. This benefit seems to be more significant in patients with clinically positive lymph nodes.

Abstract P1-11-13: DE-REAL: ITALIAN MULTICENTER EXPERIENCE OF TRASTUZUMAB DERUXTECAN IN A REAL WORLD SETTING

INTRODUCTION: Trastuzumab Deruxtecan (TDxd) is an innovative antibody drug conjugate (ADC) comprising an anti-HER2 antibody, a cleavable tetrapeptide-based linker and a potent topoisomerase I inhibitor. TDxd has demonstrated promising clinical efficacy in previously treated HER2-positive metastatic breast cancer patients (pts). Drug-drug interactions (DDIs) can influence drug activity and potentially affect treatment efficacy or determine increased toxicity. Drug-PIN® (Personalized Interactions Network) is a tool able to identify interactions between drugs and combine them with demographic, clinical and biochemical patient data. In this multicentric retrospective study, we aim to describe clinical outcomes, toxicities and drug-drug interactions (DDIs) of TDxd in a real-world population. METHODS: Pts with histological and radiological confirmed HER2+ mBC (defined as HER2 3+ or HER2 2+ with an amplification detected in SISH/FISH) who received TDxd were included in the study. The availability of complete data about clinical outcomes, toxicities and concurrent medications was needed. Pts who received at least one month of treatment were eligible. Radiological response and toxicities were evaluated following RECIST 1.1 and CTCAE v5 criteria. Drug-PIN® was used to define DDis, Drug-PIN® score and Drug-PIN® tier (green for no significant DDis and yellow, dark yellow, orange, red for increasing DDIs) for each pts. Clinical and pathological features were collected from the referral hospital in an anonymous database and analyzed with R-package. Univariate analysis was conducted calculating the AUC of ROC or the PFS using the Kaplan and Meier curves and log- rank test as appropriate. Multivariate analysis was conducted using logistic or Cox proportional hazard regression model as appropriate. RESULTS: One hundred forty-three pts were enrolled from 11 Italian oncological hospitals. Median age was 56 years (33-84). Estrogen receptor (HR) status was positive in 108 (75%) pts and negative in 35 (25%) pts. TDxd was administered as the first, second, third or subsequent line in 4 (3%), 17 (12%), 41 (29%) and 81 (56%) pts, respectively, with an average of 4 treatments received (range 1-11). Among 114 pts with measurable disease, the ORR was 68% (6% of complete response). Eight (7%) pts had a primary resistance to TDxd. Median PFS was not reached and the milestone-1 year PFS was 56.7% in the overall population. PFS at 12 months was 100% vs 54.1 % in pts receiving upfront or second versus subsequent lines (p=0.094). A toxicity of any grade was registered in 80 pts (56%). Most common toxicities were nausea (43, 30%), neutropenia (28, 19%) and asthenia (19, 13%). Severe tox was reported in 21 (15%) pts. Most common severe tox were neutropenia, nausea/vomiting and interstitial lung disease (ILD) observed in 14, 2 and 2 pts, respectively. Concomitant medications were taken by 63 pts, with 8 pts receiving more than 5 drugs. Among pts taking any medications, median Drug-PIN® score was 6.3 (range 1.7-190). 127, 11, 3 and 2 pts were in the green, yellow, dark yellow and red Drug-PIN® tier, respectively. Sixteen pts (11%) had a relevant DDI. The median PFS was not reached vs 12 months in pts with green Drug-PIN® tier compared to yellow or more, however the difference did not reach statistical significance and a longer follow up is needed. Asthenia of any grade was associated with an elevated Drug-PIN® score (AUC 0,681; P= 0.011). Severe ILD was reported in 2/16 pts with DDIs while no cases (0/124) occurred in pts with no DDIs (threshold Drug-PIN® score: 19.4/Drug-PIN® tier: &gt;yellow, P=0.0061). CONCLUSIONS: TDxd demonstrated to be effective and safe in our unselected real world population, even in heavily pretreated pts. No new safety concerns were reported. DDIs seems to be associated with specific toxicities such as asthenia and ILD.

Citation Format: Andrea Botticelli, Simone Scagnoli, Simona Pisegna, Daniele Santini, Antonella Palazzo, Roberta Scafetta, Luigi Rossi, Michelino de Laurentiis, Roberta Caputo, Annarita Verrazzo, Rossana Berardi, Vittoria Barberi, Domenico Bilancia, Giuliana D’auria, Daniele Alesini, Michela Palleschi, Agnese Fabbri, Lidia Strigari, Robert Preissner, Paolo Marchetti, Alessandra Fabi. DE-REAL: ITALIAN MULTICENTER EXPERIENCE OF TRASTUZUMAB DERUXTECAN IN A REAL WORLD SETTING [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 P1-11-13.

The role of immune profile in predicting outcomes in cancer patients treated with immunotherapy

Background

Despite the efficacy of immunotherapy, only a small percentage of patients achieves a long-term benefit in terms of overall survival. The aim of this study was to define an immune profile predicting the response to immune checkpoint inhibitors (ICIs).

Methods

Patients with advanced solid tumors, who underwent ICI treatment were enrolled in this prospective study. Blood samples were collected at the baseline. Thirteen soluble immune checkpoints, 3 soluble adhesion molecules, 5 chemokines and 11 cytokines were analyzed. The results were associated with oncological outcomes.

Results

Regardless of tumor type, patients with values of sTIM3, IFNα, IFNγ, IL1β, IL1α, IL12p70, MIP1β, IL13, sCD28, sGITR, sPDL1, IL10 and TNFα below the median had longer overall survival (p<0.05). By using cluster analysis and grouping the patients according to the trend of the molecules, two clusters were found. Cluster A had a significantly higher mean progression free survival (Cluster A=11.9 months vs Cluster B=3.5 months, p<0.01), a higher percentage of disease stability (Cluster A=34.5% vs. Cluster B=0%, p<0.05) and a lower percentage of disease progression (Cluster A=55.2% vs. Cluster B = 94.4%, p=0.04).

Conclusion

The combined evaluation of soluble molecules, rather than a single circulating factor, may be more suitable to represent the fitness of the immune system status in each patient and could allow to identify two different prognostic and predictive outcome profiles.

Network analysis to determine association between immuno-related toxicities and immune soluble profile in patients treated with anti–PD-1

2553

Background: Immune checkpoint inhibitors (ICIs) have peculiar, immune-related adverse events (irAEs), as a consequence of interfering with self-tolerance mechanisms. The incidence of irAEs varies by ICI class, administered dose and treatment schedule. The aim of the study was to define a baseline (T0) immune profile (IP) predictive of irAE development. Methods: A prospective, multicenter study evaluating the IP of 79 patients with advanced cancer, treated with anti-PD-1drugs as a first- or second-line setting was performed. The results were then correlated with irAEs onset. The IP was studied by means of multiplex assay, evaluating circulating concentration of 12 cytokines, 5 chemokines, 13 soluble immune checkpoints and 3 adhesion molecules. IDO levels were evaluated through a modified liquid chromatography–tandem mass spectrometry. Data were first pre-processed by performing logarithmic transformation and Shapiro-Wilk-test. A connectivity heatmap was obtained by calculating Spearman correlation coefficients. Two different networks of connectivity were constructed, based on the toxicity profile. Results: Toxicity was predominantly of low/moderate grade. High-grade irAEs were relatively rare, while cumulative toxicity was high (23%). A positive and statistically significant correlation between the cumulative toxicity and IP10 and IL8, sLAG3, sPDL-2 sHEVM, sCD137, sCD27 and sICAM1 was found. Moreover, patients who experienced irAEs had a markedly different connectivity pattern characterized by disruption of most of the paired connections between cytokines (all the connections of the cytokine IL8, most of the connections between the pro-inflammatory chemokines, or all the connections of CD137, CD27, and CD28), while sPDL-2 pair-wise connectivity values seemed to be intensified. Network connectivity analysis identified a total of 187 statistically significant interactions in patients without toxicity and a total of 126 interactions in patients with toxicity. Ninety-eight interactions were common to both networks, while 29 were specifically observed in patients with toxicity. Conclusions: A peculiar pattern of immune dysregulation in patients who develop irAEs was defined. This immune serological profile could lead to the design of a personalized therapeutic strategy in order to prevent, monitor and treat irAEs at an early stage.

Post-Progression Treatments after Palbociclib plus Endocrine Therapy in HR+/HER2- Metastatic Breast Cancer Patients: What Is the Better Choice?

BACKGROUND

To date, a consensus has not yet been reached about the therapy sequence after disease progression (PD) on CDK4/6 inhibitors in patients with HR+/HER2- metastatic breast cancer (MBC).

OBJECTIVES

The present study assesses, in a real-world setting, the activity of different subsequent therapies in patients who experienced a PD on palbociclib (P) + endocrine therapy (ET), to evaluate the best therapy sequence.

METHODS

This is a multicenter retrospective observational study. Records of consecutive HR+/HER2- MBC patients from January 2017 to May 2019 were reviewed. The primary endpoint was the evaluation of progression-free survival (PFS) according to subsequent treatment lines after progression on P+ET. Toxicity data were also collected.

RESULTS

The outcomes were analyzed in 89 MBC patients that had progressed on previous P+ET: 17 patients were on hormone therapy (HT) and 31 patients on chemotherapy (CT) as second-line treatments; seven patients were on HT and 34 on CT as third-line therapies. PFS of patients treated with HT as second-line therapy is significantly improved when compared with patients treated with CT (p=0.01). Considering third-line settings, the difference in PFS was not statistically different between HT and CT. A better outcome in terms of toxicity is observed among HT patients for both second- and third-line therapies.

CONCLUSIONS

patients who were progressive on P+ET could still benefit from a subsequent ET. In patients who experienced a good efficacy from prior ET, without visceral metastatic sites, HT seems the most suitable option, when compared to CT, also in terms of safety.

Tissue Immune Profile: A Tool to Predict Response to Neoadjuvant Therapy in Triple Negative Breast Cancer

Pathological complete response (pCR) after neoadjuvant chemotherapy (NACT) can predict better survival outcomes in patients with early triple negative breast cancer (TNBC). Tumor infiltrating lymphocytes (TILs), Programmed Death-Ligand 1 (PD-L1), and Cluster of Differentiation 73 (CD73) are immune-related biomarkers that can be evaluated in the tumor microenvironment. We investigated if the contemporary expression of these biomarkers combined in a tissue immune profile (TIP) can predict pCR better than single biomarkers in TNBC. Tumor infiltrating lymphocytes (TILs), CD73 expression by cancer cells (CC), and PD-L1 expression by immune cells (IC) were evaluated on pre-NACT biopsies. We defined TIP positive (TIP+) as the simultaneous presence of TILS ≥ 50%, PD-L1 ≥ 1%, and CD73 ≤ 40%. To consider the effects of all significant variables on the pCR, multivariate analysis was performed. Akaike information criterion (AIC) and Bayesian information criterion (BIC) were used for model selection. We retrospectively analyzed 60 biopsies from patients with TNBC who received standard NACT. Pathological complete response was achieved in 23 patients (38.0%). Twelve (20.0%) cases resulted to be TIP+. The pCR rate was significantly different between TIP+ (91.7%) and TIP- (25.0%) (p < 0.0001). Using a multivariate analysis, TIP was confirmed as an independent predictive factor of pCR (OR 49.7 (6.30-392.4), p < 0.0001). Finally, we compared the efficacy of TIP versus each single biomarker in predicting pCR by AIC and BIC. The combined immune profile is more accurate in predicting pCR (AIC 68.3; BIC 74.5) as compared to single biomarkers. The association between TIP+ and pCR can be proposed as a novel link between immune background and response to chemotherapy in TNBC, highlighting the need to consider an immunological patients' profile rather than single biomarkers.

Abstract P5-11-18: Real-world evidence of efficacy and activity of palbociclib plus endocrine therapy and post-progression treatments in HR+/HER2- metastatic breast cancer patients: The PALPract study

Background: Several randomized clinical trials clearly demonstrated that adding palbociclib (P) to endocrine therapies (ET), such as letrozole (LT) or fulvestrant (FLV), significantly improves outcome both in first-line/endocrine sensitive and second-line/endocrine resistant hormone receptor positive (HR+), human epidermal growth factor receptor 2 negative (HER2) metastatic breast cancer (MBC) patients (pts).

The aims of the present study were to assess efficacy, activity and toxicity of P combined with either LT or FLV in a real world setting, and to study the efficacy and activity of treatments administered after progression to P + ET.

Methods: Records of 245 consecutive HR+/HER2- MBC patients from 14 Italian cancer centers were reviewed in this observational study. Primary end-point was progression-free survival (PFS) obtained with P+ET; secondary end-points were overall response rates (ORR) and clinical benefit rate (CBR) obtained with P+ET and with post-progression treatments, as well as overall survival (OS), PFS to subsequent treatment lines and post-progression survival (PPS).

Results: Overall 245 pts were treated with P+ET from April 2014. Of them, 116 (47%) received it in first-line setting, 70 (28%) in second-line and the rest (68 pts, 25%) in subsequent lines. Median age was 60 (35-80) years and median ECOG performance status was 0. Seventy-three pts (30%) had more than two metastatic sites and 75 (31%) had visceral metastasis. Ninenty-one (37%) pts received P+LT and 92 (37%) were treated with P+FLV. For 15 (6%) premenopausal pts an LHRH analogue was added to P+ET. In 77 (41%) patients a biopsy of a metastatic lesion was performed.

Among the 116 pts treated in first-line setting, median PFS was 14.7 (95% CI 12.0-17.3) and 15.1 (95%CI 8.6-21.6) months for pts receiving P+LT and P+FLV, respectively. ORR was 48% (95% CI: 39-57%) and CBR was 75% (95% CI, 66-82%). Four (3%) complete responses (CR), 52 (45%) partial responses (PR), 31 (27%) stable disease (SD) and 11 (9%) progression disease (PD) were observed as best response; 18 pts were not yet evaluable. Among the 70 pts treated in second-line setting, median PFS was 10.8 (95%CI 0-24.3) and 7.9 (95%CI 3.3-12.5) months, for pts receiving P+LT and P+FLV, respectively. The ORR was 26% (95% CI: 16-38) and the CBR was 66% (95% CI, 53-76). One CR (1%), 17 PR (24%), 28 SD (40%) and 13 PD (18.5%) were observed as best response, while 9 were not yet evaluable. Best response was achieved after a median of 5 cycle.

At time of the current analysis, 50 pts experienced PD during P+ET. Of them, 38 (76%) received chemotherapy (capecitabine, eribulin, nab-paclitaxel, paclitaxel+bevacizumab, vinoreline) and 12 (24%) ET. To date, only 5 pts progressed during these therapies, preventing us for evaluating secondary end-points regarding efficacy and activity.

The most frequent adverse event (AE) was grade 3-4 neutropenia (31%), with febrile neutropenia reported in 5 (2%) cases. Main non-hematological AEs were fatigue and gastrointestinal symptoms (diarrhea and stypsis).

Conclusions: Our findings confirm the efficacy and safety of P+ET as first/second-line treatment for HR+/HER2- MBC pts, even in a non-selected, real world population. Since data regarding the efficacy and activity of post-progression therapies were not mature at the time of the current analysis, they will be subsequently presented.

Citation Format: Alessandra Fabi, Michelangelo Russillo, Mariangela Ciccarese, Simone Scagnoli, Francesco Schettini, Giuseppe Buono, Vito Lo Russo, Grazia Arpino, Rosalba Rossella, Giuseppina Sarobba, Marianna Giampaglia, Patrizia Pellegrini, Simonetta Stani, Michela Palleschi, Vincenzo Adamo, Francesca Morelli, Maria Agnese Fabbri, Cecilia Nistico, Gianluigi Ferretti, Giovanna Catania, Simona Pisegna, Diana Giannarelli, Francesco Cognetti. Real-world evidence of efficacy and activity of palbociclib plus endocrine therapy and post-progression treatments in HR+/HER2- metastatic breast cancer patients: The PALPract study [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P5-11-18.

p38 MAPK activation controls the TLR3-mediated up-regulation of cytotoxicity and cytokine production in human NK cells

Natural killer (NK) cells are a component of the innate immunity against viral infections through their rapid cytotoxic activity and cytokine production. Although the synthetic double-stranded (ds) RNA polyinosinic-polycytidylic acid (poly I:C), a mimic of a common product of viral infections, is known to rapidly up-regulate their in vivo functions, NK cell ability to directly respond to dsRNA is still mostly unknown. Our results show that treatment with poly I:C significantly up-regulates both natural and CD16-mediated cytotoxicity of highly purified human NK cells. Poly I:C also induces the novel capability of producing CXCL10 chemokine in human NK cells and synergistically enhances interferon-gamma (IFN-gamma) production induced by either adaptive or innate cytokines. In accordance with the expression of Toll-like receptor-3 (TLR3) and of TRIF/TICAM-1 adaptor, poly I:C stimulation induces the activation of interferon regulatory factor-3 (IRF-3) transcription factor and of p38 mitogen-activated protein kinase (MAPK) in human NK cells. Finally, we demonstrate that p38 MAPK activity is required for the dsRNA-dependent enhancement of cytotoxicity and CXCL10 production. The occurrence of dsRNA-induced signaling and functional events closely correlates with the TLR3 mRNAprofile in different NK cell populations. Taken together, these data identify p38 as a central component of NK cell ability to directly respond to dsRNA pathogen-associated molecular pattern (PAMP).

Src-dependent Syk activation controls CD69-mediated signaling and function on human NK cells

CD69 C-type lectin receptor represents a functional triggering molecule on activated NK cells, capable of directing their natural killing function. The receptor-proximal signaling pathways activated by CD69 cross-linking and involved in CD69-mediated cytotoxic activity are still poorly understood. Here we show that CD69 engagement leads to the rapid and selective activation of the tyrosine kinase Syk, but not of the closely related member of the same family, ZAP70, in IL-2-activated human NK cells. Our results indicate the requirement for Src family kinases in the CD69-triggered activation of Syk and suggest a role for Lck in this event. We also demonstrate that Syk and Src family tyrosine kinases control the CD69-triggered tyrosine phosphorylation and activation of phospholipase Cgamma2 and the Rho family-specific exchange factor Vav1 and are responsible for CD69-triggered cytotoxicity of activated NK cells. The same CD69-activated signaling pathways are also observed in an RBL transfectant clone, constitutively expressing the receptor. These data demonstrate for the first time that the CD69 receptor functionally couples to the activation of Src family tyrosine kinases, which, by inducing Syk activation, initiate downstream signaling pathways and regulate CD69-triggered functions on human NK cells.

The AML1 gene: a transcription factor involved in the pathogenesis of myeloid and lymphoid leukemias

BACKGROUND AND OBJECTIVE

The AML1 gene was identified in 1991 by cloning the t(8;21) chromosome translocation associated with FAB M2 acute myeloid leukemia (AML). AML1 encodes a nuclear transcription factor (TF) which shows homology in its 5' part with the Drosophila melanogaster segmentation gene, runt, and contains a transactivation domain in the carboxyterminal portion. In the t(8;21), AML1 is fused to the ETO (MTG8) gene, resulting in a hybrid AML1/ETO mRNA, which in turn is translated into a chimeric protein. The objective of this article is to review here the main structural and biological features of AML1 and of its fusion products, with special focus on their clinical correlations and their potential usefulness for prognostic and monitoring studies in human leukemia.

EVIDENCE AND INFORMATION SOURCES

The material examined in the present review includes articles and abstracts published in journals covered by the Science Citation Index and Medline.

STATE OF ART

The normal AML-1 protein forms the alpha-subunit of the heterodimeric TF core binding factor (or CBF), whose beta-subunit is encoded by the CBF beta gene on chromosome 16q22. CBF beta is rearranged and fused to the MYH11 gene in the AML M4Eo-associated inv(16) aberration. Thus, the two most common chromosome abnormalities of AML, i.e. t(8;21) and inv(16), affect the two subunits of the same target protein. This suggests that the wild type CBF must exert an important role in the control of myeloid cell growth and/or differentiation. Evidence that AML1 is a pivotal regulator of definitive hematopoiesis has been recently provided by analyzing AML1 knockout mice. The chromosome region 21q22, where AML1 maps, is involved in several other karyotypic aberrations, such as the t(3;21) translocation associated with a subset of therapy-related myelodysplastic syndromes and AML, and the blast phase of chronic myelogenous leukemia. In this abnormality, three distinct genes: EVI1, EAP, MDS1, located on chromosome band 3q26, have been identified that may recombine with AML1. Finally, the recently cloned t(12;21) translocation has been found to involve the TEL gene (coding for a novel TF) on 12p13, and AML1 on 21q22. This alteration, which results in the production of a TEL/AML1 chimeric protein, is restricted to pediatric B-lineage acute lymphoid leukemia (ALL), where it represents the most frequent molecular defect known to date (up to 25% of cases). Strikingly, the same t(12;21) is identified in only 0.05% of pediatric B-lineage ALL cases analyzed by conventional karyotyping. Other relevant characteristics of TEL/AML1-positive ALL are frequent deletion of the other TEL allele and association with an excellent prognostic outcome.

PERSPECTIVES

It is expected that future studies will provide more detailed information on the leukemogenic effect of AML1 alterations, and better define the prognostic relevance of detecting the hybrid proteins formed by this gene at diagnosis and during remission.

Detection of homozygous deletions of the cyclin-dependent kinase 4 inhibitor (p16) gene in acute lymphoblastic leukemia and association with adverse prognostic features

A recently described putative tumor suppressor gene, the cyclin-dependent kinase 4 inhibitor (p16), has been shown to be altered by deletions and/or point mutations in various human cancers. To assess the incidence and clinico-biologic correlations of p16 homozygous deletion in hemopoietic tumors, we studied a panel of 244 DNA samples representative of distinct acute (99 cases) and chronic (57 cases) leukemia subtypes, myelodysplastic (22 cases) and myeloproliferative (15 cases) syndromes, and lymphomas (51 cases). A 361-bp probe complementary to the p16 exon 2 gene sequences was generated by polymerase chain reaction and used in Southern blot hybridization against these tumor DNAs. Homozygous deletions of p16 (p16-/-) were detected in 10 of 58 (17%) cases of acute lymphoblastic leukemia (ALL) of either B or T lineage and in no other tumors. Single-strand conformation polymorphism analysis of p16 exons 1 and 2 was also performed in 40 of the 58 ALL cases and in 16 lymphomas. In no cases were point mutations detected. The comparison of clinical features at presentation in p16-/- and in p16 germline ALL cases showed a greater leukemic cell mass (P = .001) and higher white blood cell counts (P = .01) in the former group. Two ALL cases in which diagnostic and relapse DNA samples were available showed p16-/- in both specimens. We conclude that homozygous p16 gene deletions characterize a subset of ALL with features of aggressive disease.