Personalized combination of neoadjuvant domatinostat, nivolumab and ipilimumab in macroscopic stage III melanoma patients stratified according to the interferon-gamma signature: The DONIMI study

TPS10087

Background: Previous OpACIN and OpACIN-neo studies, investigating neoadjuvant ipilimumab (IPI) plus nivolumab (NIVO), demonstrated high pathologic response rates (74-78%) and favorable long-term outcomes in patients (pts) achieving pathologic response; at 36 and 18 months follow-up, respectively, only 1/71 (1.4%) pts with response has relapsed. In contrast, pts without pathologic response (pNR) have a poor prognosis; 15/23 (65.2%) have relapsed so far. This emphasizes the need for baseline biomarkers predictive of non-response and new neoadjuvant treatment combinations for these pts. In our previous studies, baseline interferon-gamma (IFN-γ) signature low pts were less likely to respond to neoadjuvant IPI plus NIVO. The DONIMI study tests the combination of NIVO +/- IPI with domatinostat (DOM), a class 1 histone deacetylase inhibitor, according to the IFN-γ signature in the tumor. Based on the signature previously described by Ayers et al. we have developed a neoadjuvant IFN-γ signature algorithm that will be used for the first time to classify pts in this prospective trial. Methods: The aim of this two-center investigator-initiated phase 1b study is to assess the safety and feasibility of neoadjuvant NIVO +/- DOM +/- IPI in 45 stage III melanoma pts with RECIST 1.1 measurable de-novo or recurrent disease. IFN-γ signature high pts (n = 20) will be randomized (stratified by center) to Arm A (2 cycles NIVO 240mg q3wk) or Arm B (2 cycles NIVO 240mg q3wk + DOM 200mg twice daily (BID), d1-14, q3wk). IFN-γ signature low pts (n = 25) will be randomized to Arm C (2 cycles NIVO 240mg q3wk + DOM 200mg BID, d1-14, q3wk) or Arm D (2 cycles NIVO 240mg q3wk + IPI 80mg q3wk + DOM 200mg once daily (OD), d1-14, q3wk). Based on safety data of the first 5 pts in arm D, the remaining pts will be treated with either a higher dosing scheme (200mg BID, d1-14, q3wks), a lower dosing scheme (100mg OD, d1-14, q3wks) or the same dosing scheme (200mg OD, d1-14, q3wks). The primary endpoint is safety and feasibility. A treatment arm will be declared as not feasible if 2/5 or 3/10 pts cannot adhere to the preplanned time of surgery (week 6 +/- 1week) due to treatment-related adverse events. Biopsies (week 0, 3), blood samples (week 0, 3, 6, 12) and feces (week 0, 3, 6) will be collected for translational research. The first patient was enrolled on January 23th, 2020. Clinical trial information: NCT04133948.

Twenty-four months RFS and updated toxicity data from OpACIN-neo: A study to identify the optimal dosing schedule of neoadjuvant ipilimumab (IPI) and nivolumab (NIVO) in stage III melanoma

10015

Background: Early results of the OpACIN-neo study testing 3 different dosing schedules of neoadjuvant IPI + NIVO demonstrated that 2 cycles IPI 1mg/kg + NIVO 3mg/kg (IPI1NIVO3, arm B) was the most favorable schedule with 20% grade 3-4 immunotherapy-related adverse events (irAEs) and a pathologic response rate (pRR) of 77%. After a median follow-up (FU) of 8.3 months, none of the 64 patients (pts) with a pathologic (path) response ( < 50% viable tumor cells) versus 9/21 (43%) without a path response had relapsed. Here, we present the updated 2-year RFS, EFS and long-term toxicity data. Methods: In the phase 2 multi-center OpACIN-neo trial, 86 stage III melanoma pts with resectable and RECIST 1.1 measurable lymph node metastasis were randomized between 3 different dosing schedules of neoadjuvant IPI + NIVO: arm A: 2x IPI3+NIVO1 Q3W (n = 30), arm B: 2x IPI1+NIVO3 Q3W (n = 30), and arm C: 2x IPI3 Q3W followed by 2x NIVO3 Q2W (n = 26). Lymph node dissection was scheduled at week 6. Primary endpoints were toxicity, radiologic RR and pRR; RFS and EFS were secondary endpoints. Results: After a median FU of 24.6 months, the median RFS and EFS was not reached in any of the 3 arms. In total, 2 pts progressed before surgery, 12 pts relapsed (11 pts without path response and 1 pt with pCR) and 5 pts died (4 due to melanoma and one pt due to toxicity). Estimated 24-months RFS was 84% (95% CI 76-92%) for the total population, 97% (95% CI 93-100%) for pts with a path response and 36% (95% CI 17-74%) for pts without a path response. Estimated 24-months EFS for the total population was 82% (95% CI 74-91%). RFS and EFS did not differ between the arms. Of the 81 pts alive, 55 (68%) have ongoing irAEs; only 2 (3%) pts have ≥ grade 3 irAEs. Most frequent ongoing irAEs were vitiligo (35%), fatigue (14%), sicca syndrome (11%), rash (10%), arthralgia (7%) and endocrine toxicities (20%). 17 pts need hormone replacement therapy: 11 (14%) thyroid hormone and 7 (9%) hydrocortisone. No difference between treatment arms was observed. Ongoing surgery-related AEs were observed in 31 (38%) pts of which lymphedema was seen most frequently (17 pts; 21%). Conclusions: Extended follow-up data shows that 2 cycles of neoadjuvant IPI + NIVO without adjuvant therapy induces durable RFS. While almost no ongoing high-grade irAEs were observed, the majority of pts have low-grade ongoing toxicities. These outcomes strongly support the need to test 2 cycles of neoadjuvant IPI1+NIVO3 versus adjuvant anti-PD-1 in a randomized phase 3 trial. Clinical trial information: NCT02977052.

Health-related quality of life in stage III melanoma patients treated with neoadjuvant ipilimumab and nivolumab followed by index lymph node excision only, compared to therapeutic lymph node dissection: First results of the PRADO trial

10064

Background: Neoadjuvant ipilimumab and nivolumab induces high pathologic response rates of 74-78% (OpACIN and OpACIN-neo trial), thus the role of Therapeutic Lymph Node Dissections (TLND) in patients with major pathologic responses (MPR: pathological (near) complete response) is now unclear. In the PRADO trial, TLND was omitted in patients with MPR in their index lymph node ((ILN), the largest LN marked prior to neoadjuvant therapy). We sought to determine if less extensive surgery is associated with better Health Related Quality of Life (HRQoL). These are the first results of the comparison of HRQoL between patients undergoing a TLND or less extensive ILN excision. Methods: HRQoL was assessed with the European Organisation for Research and Treatment of Cancer QoL questionnaire-C30 (QLQ-C30). A generalized estimation equation was used to assess the difference in HRQoL outcomes between patients who underwent TLND (pathological non- and partial-responders, pNR/pPR) versus those who did not (pathological (near)complete responders, pNCR/pCR). Differences were adjusted for age, gender and follow-up (FU, in weeks), but not for pathological responses (pNR, pPR, pNCR & pCR). Differences in QLQ-C30 scores were classified as clinically important according to published guidelines. Results: A total of 49 patients from the PRADO study had reached at least 24 weeks FU, and were included in the first explorative analysis. The median age of this study population was 58 years (range, 22-84). Questionnaire completion rates were high: 94% at baseline, 100%, 90%, 88% at week 6, 12 and 24, respectively. Sixteen (33%) patients underwent TLND versus 33 (67%) who had ILN excision only. Over a FU period of 24 weeks, patients who underwent TLND scored significantly lower on global (68 vs 78, adjusted difference (diff) = -9.53, p = .005), physical (84 vs 94 diff = -11.1, p = < .001), emotional (69 vs 83, diff = -11.7, p = .001), role (70 vs 85, diff = -13, p = .004), and social functioning (81 vs 91, diff = -8.9, p = .016) and had a higher symptom burden of fatigue (35 vs 23, diff = 11.1, p = .004), insomnia (38 vs 18, diff = 16.6, p = .002) and financial impact (12 vs 4, diff = 7.9, p = .027) than patients undergoing ILN excision only. These differences were indicated as clinically relevant. Conclusions: First results from PRADO suggest that reducing the extent of surgery following neoadjuvant immunotherapy might result in better HRQoL of high-risk stage III melanoma patients. Clinical trial information: NCT02977052.

First safety and efficacy results of PRADO: A phase II study of personalized response-driven surgery and adjuvant therapy after neoadjuvant ipilimumab (IPI) and nivolumab (NIVO) in resectable stage III melanoma

10002

Background: OpACIN-neo tested 3 dosing schemes of neoadjuvant (neoadj) IPI+NIVO and identified 2 cycles of IPI 1mg/kg + NIVO 3mg/kg (I1N3) as the most favorable with a pathologic (path) response rate (pRR) of 77% and 20% grade 3-4 irAEs. After 17.6 months median FU, 1/64 (2%) patients (pts) with path response vs 13/21 (62%) of the non-responders ( > 50% viable tumor cells; pNR) had relapsed. We hypothesized that therapeutic lymph node dissection (TLND) could be omitted in pts achieving a complete or near-complete path response (≤10% viable tumor cells; major path response, MPR) in the index node (largest LN metastasis: ILN), whereas additional adjuvant (adj) therapy might improve the outcome of pNR pts. Methods: PRADO is an extension cohort of the multi-center phase 2 OpACIN-neo study that aims to confirm the pRR and safety of neoadj I1N3 and to test response-driven subsequent therapy. Pts with RECIST 1.1 measurable clinical stage III melanoma were included to receive 2 cycles of neoadj I1N3 after marker placement in the ILN. ILN resection was planned at wk 6. Pts that achieved MPR in the ILN did not undergo TLND; pts with pPR ( > 10 – ≤50% viable tumor cells) underwent TLND; and pts with pNR underwent TLND and received adj NIVO or targeted therapy (TT) for 52 wks +/- radiotherapy (RT). Primary endpoints were pRR in the ILN and 24-month RFS. Estimated toxicity rates at wk 12 were calculated using a Kaplan Meier based method. Results: Between Nov 16, 2018 and Jan 3, 2020, 99 of 114 screened pts were eligible and enrolled. So far, 86 pts had ≥12 wks FU. 70/99 pts achieved a path response in the ILN (pRR 71%, 95% CI 61% - 79%); 60 (61%) had MPR. TLND was omitted in 58 (97%) of the MPR pts. There were 28 non-responders; 7 developed distant metastasis before ILN resection. To date, 8 of the 21 pNR pts had adj NIVO, 7 had adj TT and 7 had adj RT. The estimated grade 3-4 irAE rate at wk 12 was 24%. Due to toxicity, 10 pts (10%) received only 1 cycle I1N3 and in 3 pts ILN resection was not performed: 2 of these pts underwent TLND at wk 9 and one pt was not evaluated for path response. At data cutoff, the surgery-related grade 1,2 and 3 AE rates were 29%, 10% and 0% in pts who underwent ILN resection only vs 21%, 30% and 9% in pts who underwent subsequent TLND (p = 0.004). At ASCO 2020 all pts will have reached ≥12 wks FU. Conclusions: Neoadj I1N3 treatment induced a high pRR with tolerable toxicity. TLND was omitted in a major subset of pts, reducing surgical morbidity. Longer FU is needed to report safety and RFS when TLND is omitted in MPR pts. Clinical trial information: NCT02977052.

What are the appropriate thresholds for High Quality Performance Indicators for breast surgery in Australia and New Zealand?

Aim

To evaluate BreastSurgANZ members’ compliance at various threshold rates for 4 evaluable High-Quality Performance Indicators (HQPIs) introduced to improve patient care. To benchmark global best practice to assist in determining the eventual threshold standards.

Method

BreastSurgANZ Quality Audit data 2012–2016 & 2018 was used to determine rates of attainment through a range of thresholds for 4 HQPI’s. Rates were assessed for different volume surgeons and comparison made to international standards.

Results

1.3761 patients needing mastectomy for in situ disease, if the threshold rate for immediate breast reconstruction (IBR) was ≥ 40% then 30% of all members and 78% of very high-volume surgeons achieved that rate, which is comparable to international recommendations.

2.26,007 patients requiring mastectomy, if the threshold rate for IBR was ≥ 20% then 28% of all surgeons and 78% very high-volume surgeons met the standard. This is below most international recommendations.

3. For 31,698 invasive tumours ≤ 2 cm, if the threshold rate for breast conservation was ≥ 70% then 64% of all surgeons met the standard; 70% is comparable internationally.

4.1382 women =<50 years if the threshold rate for neoadjuvant chemotherapy was set at ≥ 15% then 36% of surgeons complied; 15% is below most international recommendations.

Conclusions

Even at these modest thresholds there are low levels of achievement by BreastSurgANZ members with high volume surgeons more likely to comply. These thresholds are either comparable or lower than globally accepted standards. Members should strive to meet, even exceed these important goals as they are a metric of improved patient care.

•

High quality performance indicators are important for driving improvements in care.

•

Our threshold standards for IBR for insitu disease are comparable internationally.

•

Threshold indicators for invasive breast cancer are well below international standards.

•

Members are achieving internationally comparable rates of breast conservation.

•

Use of neoadjuvant chemotherapy for women <50yrs is below international standards.

Abstract PD9-01: Prospect trial MRI findings: High incidence of occult cancers in apparently low risk cases

Background and Aim The role of staging breast magnetic resonance imaging (MRI) of apparently localised breast cancer is controversial. Some recommend MRI in selected ‘high risk’ situations, while others suggest it has little or no role. Few studies demonstrate improved outcomes associated with MRI. ANZ 1002 : Post-operative Radiotherapy Omission in Selected Patients with Early breast Cancer Trial (PROSPECT) is a prospective single-arm study using preoperative MRI to identify a group of patients with early breast cancer in whom radiotherapy might be safely omitted. Inclusion criteria include nil/minimal or mild Background Parenchymal Enhancement (BPE), unifocal pT1N0 invasive cancer, not TNBC, no LVI. Since September 2011, 443 patients have undergone MRI and 201 have had radiotherapy omitted. Primary analysis of ipsilateral local recurrence is due in May 2021. Here we report imaging, subsequent biopsy findings for occult lesions and mastectomy rates. Methods All patients who underwent PROSPECT MRI in addition to mammogram (MMG) and ultrasound (US) were included. Imaging findings on MMG, US and MRI were documented. Breast Imaging-Reporting and Data System (BIRADS) 4 or higher lesions on MRI were subject to biopsy under US if possible, or MRI or surgical biopsy if not. Pathologic results of lesions identified by MRI were described and the extent of surgery was documented. Results: Over 8 years, 443 patients were identified; mean age 63 years (range: 50 to 84), median index tumour size 13mm (range: 2 to 111), grade 1 (188), grade 2 (212) or grade 3 (38). MRI showed nil/minimal or mild BPE in 336 patients and moderate or marked BPE in 107. A total of 189 occult BIRADS&gt;3 lesions were identified in 140 (32%) patients; 135 (71%) were ipsilateral; 36 (19%) could be identified and biopsied with MRI-directed, US-guided biopsy, while 63 (33%) underwent MRI-guided biopsy, 82 (43%) surgical biopsy after MRI-guided hook needle localisation, 1 underwent a stereotactic biopsy and 7 were not biopsied due to proximity to the index lesion. A total of 51 occult malignant lesions were identified in 40 patients (9% of the total patient cohort). 36 were invasive cancer and 15 were DCIS. There were 17 invasive and 14 DCIS ipsilateral occult lesions in 26 patients (6% of total cohort) and 19 invasive and 1 DCIS contralateral lesions in 18 patients (4% of total cohort) An additional 16 lesions in 9 patients were malignant but considered part of the primary cancer. There were 3 ‘at risk’ lesions: 1 LCIS and 2 ADH. There were a total of 112 benign biopsies in 95 patients. 9 patients in the cohort (2%) underwent total mastectomy due to pathological extent of disease of the index cancer (4), multicentric cancer (3) or patient choice (2). A higher proportion of patients with moderate/marked BPE had occult lesions (29% vs. 39%, p=0.09) and occult malignant lesions (8% vs. 13%, p=0.09) compared to those with less BPE. Conclusion Breast MRI in selected, low risk patients over 50 years old with low risk apparently unifocal cancer identified an occult breast cancer in 9% of patients. Only 2% underwent total mastectomy. Primary analysis of PROSPECT in 2021 will help define the clinical utility of these findings.

Background Parenchymal EnhancementNil/Mild (n=336)Mod/Marked (n=107)p-valueNo occult lesions237 (71%)66 (62%)0.09Occult lesions99 (29%)41 (38%)No occult malignant lesions310 (92%)93 (87%)0.09Occult malignant lesions26 (8%)14 (13%)Age &lt;65192 (57%)65 (61%)0.51Age &gt;65144 (43%)42 (39%)

Citation Format: Allison Rose, Arlene Mou, John Collins, Anita Skandarajah, Janemary Hughes, Heath Badger, Helen Braggett, Nicholas Zdenkowski, Rebecca Asher, Andrew Spillane, Boon Chua, Gregory Bruce Mann. Prospect trial MRI findings: High incidence of occult cancers in apparently low risk cases [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 PD9-01.

On the frontiers of change: breast surgeons' views on demarcation between surgical sub-specialties in Australia

BACKGROUND

The emergence of breast oncoplastic surgery provides women with more surgical options for improved aesthetics following breast-conserving surgery and for breast reconstruction (BR) following mastectomy. For some established breast and plastic surgeons, this development may be perceived as increasing competition for patients and raises the potential for demarcation issues between and within surgical sub-specialties. The objectives of the study were to document surgeons' views on demarcation between general/breast, oncoplastic/breast and plastic reconstructive breast surgeons in Australia, to examine the potential impact demarcation issues may have on informed patient choice and to recommend ways of reducing them.

METHODS

In-depth qualitative interviews were conducted with a convenience sample of 31 (22 oncoplastic and nine plastic reconstructive) surgeons who performed BR.

RESULTS

Descriptive analysis of the interviews revealed a range in the perceptions of the extent of demarcation. Six common themes were identified: oncoplastic techniques are unnecessary and potentially unsafe; reconstructive surgery should be left to 'the experts'; non-referral of patients for discussion of surgical options they do not offer; professional jealousy; workload capacity; and the old versus the new guard. Potential solutions suggested by the participants focused on improving relations between oncoplastic and plastic reconstructive surgeons and changes to breast surgical training.

CONCLUSION

While most surgeons were optimistic about the current divide diminishing with time, a more pro-active stance is required if patient-centred care is to be improved. Roundtable discussions with a broad range of stakeholders are planned to begin this process.

Window of opportunity treatment in breast cancer

Window of opportunity therapies, which involve short-term administration of systemic therapy between cancer diagnosis and surgery, have raised significant interest in recent years as a mean of assessing the sensitivity of a patient's cancer to therapy prior to surgery. There is now compelling evidence that in patients with early stage hormone-receptor positive breast cancer, a 2-week preoperative treatment with standard hormone therapies in a preoperative window period provides important prognostic information, which in turn helps to aid decision-making regarding treatment options. Changes in short-term biomarker endpoints such as cell proliferation measured by Ki-67 can act as surrogate markers of long-term outcomes. Paired tissues obtained pre- and post-investigational treatment, without having to subject the patient to additional biopsies, can then be used to conduct translational research to investigate predictive biomarkers and pharmacodynamics. In this review, we will examine the utility and challenges of window of opportunities therapies in breast cancer in the current literature, and the current Australian and international trial landscape in this clinical space.

Increasing access to breast reconstruction for women living in underserved non-metropolitan areas of Australia

PURPOSE

The potential quality of life benefits of breast reconstruction (BR) for women who have undergone mastectomy for breast cancer have long been recognised. While many women will not want to have BR, international best-practice guidance mandates that all should be given the choice. The aim of this article is to highlight potential policies to support patients' informed discussion of BR options and to improve access to BR for women living in underserved locations.

METHODS

Ninety semi-structured interviews were conducted from May 2015 to May 2017 with a convenience sample of 31 breast reconstructive surgeons, 37 breast cancer health professionals and a purposive sample of 22 women who underwent mastectomy as part of their breast cancer treatment. Breast, plastic reconstructive surgeons and health professionals based in major cities also provided information about how they cared for patients from more remote areas.

RESULTS

Analysis of interview data revealed a range of barriers that were grouped into four major categories describing issues for women living outside major cities: population characteristics associated with lower socioeconomic status; locational barriers including limited health services resources and distance; administrative barriers such as hospital policies and inadequate support for women who need to travel; and surgical workforce recruitment barriers.

CONCLUSIONS

Suggestions for potential solutions included the following: greater geographical centralisation of BR services within major cities; the creation of designated breast centres with minimum caseload requirements similar to the UK's system; and a buddy system, whereby smaller hospitals network with multidisciplinary teams based in larger hospitals.

Single-Arm Longitudinal Study to Evaluate a Decision Aid for Women Offered Neoadjuvant Systemic Therapy for Operable Breast Cancer

Background: Neoadjuvant systemic therapy (NAST) is an increasingly used treatment option for women with large operable or highly proliferative breast cancer. With equivalent survival outcomes between NAST and up-front surgery, the situation-specific preference-sensitive nature of the decision makes it suitable for a decision aid (DA). This study aimed to develop and evaluate a DA for this population. Methods: A DA booklet was developed according to international standards, including information about adjuvant and neoadjuvant treatment, outcome probabilities, and a values clarification exercise. Eligible women, considered by investigators as candidates for NAST, were enrolled in a multi-institutional, single-arm, longitudinal study. Patient-reported outcome measure questionnaires were completed pre- and post-DA, between chemotherapy and surgery, and at 12 months. Outcomes were feasibility (percentage of eligible patients accessing the DA); acceptability to patients (percentage who would recommend it to others) and clinicians (percentage who would use the DA in routine practice); and decision-related outcomes. Results: From 77 eligible women, 59 were enrolled, of whom 47 (79.7%; 95% CI, 69.4-89.9) reported having read the DA; 51 completed the first post-DA questionnaire. Of these 51, 41 participants (80.4%; 95% CI, 69.5-91.3) found the DA useful for their decision about NAST. Of 18 responding investigators, 16 (88.9%; 95% CI, 74.4-103.4) indicated they would continue to use the DA in routine practice. Post-DA, decisional conflict decreased significantly (P<.01); anxiety and distress decreased significantly; and 86.3% (95% CI, 73.7-94.3) achieved at least as much decisional control as they desired. Conclusions: This DA was feasible and acceptable to patients and clinicians, and improvement in decision-related outcomes was demonstrated when used in combination with clinical consultations. This DA could safely be implemented into routine practice for women considering NAST for operable breast cancer.

Patterns of immediate breast reconstruction in New South Wales, Australia: a population-based study

Background

The rate of immediate breast reconstruction (IBR) following mastectomy for breast cancer in Australia is low and varies between regions. To date, no previous Australian studies have examined IBR rates between all hospitals within a particular jurisdiction, despite hospitals being an important known contributor to variation in IBR rates in other countries.

Methods

We used cross‐classified random‐effects logistic regression models to examine the inter‐hospital variation in IBR rates by using data on 7961 women who underwent therapeutic mastectomy procedures in New South Wales (NSW) between January 2012 and June 2015. We derived IBR rates by patient‐, residential neighbourhood‐ and hospital‐related factors and investigated the underlying drivers for the variation in IBR.

Results

We estimated the mean IBR rate across all hospitals performing mastectomy to be 17.1% (95% Bayesian credible interval (CrI) 12.1–23.1%) and observed wide inter‐hospital variation in IBR (variance 4.337, CrI 2.634–6.889). Older women, those born in Asian countries (odds ratio (OR) 0.5, CrI 0.4–0.6), residing in neighbourhoods with lower socioeconomic status (OR 0.7, CrI 0.5–0.8 for the most disadvantaged), and who underwent surgery in public hospitals (OR 0.4, CrI 0.1–1.0) were significantly less likely to have IBR. Women residing in non‐metropolitan areas and attending non‐metropolitan hospitals were significantly less likely to undergo IBR than their metropolitan counterparts attending metropolitan hospitals.

Conclusion

Wide inter‐hospital variation raises concerns about potential inequities in access to IBR services and unmet demand in certain areas of NSW. Explaining the underlying drivers for IBR variation is the first step in identifying policy solutions to redress the issue.

Pathological response and survival with neoadjuvant therapy in melanoma: A pooled analysis from the International Neoadjuvant Melanoma Consortium (INMC)

9503

Background: Pathological complete response (pCR) to neoadjuvant systemic therapy (NST) correlates with survival, and is recognized as a path to regulatory approval in several cancers. Recent trials have reported that neoadjuvant immunotherapy (IT) and targeted therapy (TT) regimens achieve high pCR rates and impressive recurrence-free survival in stage III melanoma, however, the relationship between pCR, relapse-free (RFS) and overall survival (OS) in larger datasets of melanoma patients (pts) remains unknown. Methods: We pooled data from 6 modern NST clinical trials of anti-PD-1 based immunotherapy or BRAF/MEK targeted therapy conducted across institutions participating in the INMC. Pts with RECIST measurable, surgically resectable clinical stage III melanoma who underwent surgery were included. NST regimens included nivolumab (as monotherapy or in combination with ipilimumab), pembrolizumab or dabrafenib+trametinib. Baseline disease characteristics, treatment regimen, pCR and RFS were examined. Results: 184 pts with clinical stage III melanoma (AJCCv7: 100 IIIB, 84 IIIC) completed NST (133 IT, 51 TT) and underwent surgery. Median age was 57y (range 18-87). A pCR was observed in 41% of patients; 51 (38%) with IT and 24 (47%) with TT. Median follow-up post-surgery is 13 mo (95% CI 12-16); 10 mo with IT and 22 mo with TT. 44 (24%) pts have recurred (17 loco-regional, 21 distant, 6 both sites at first recurrence), 18 (14%) after IT and 26 (51%) after TT. 12-month RFS was improved with IT vs TT (83% vs 65%, p < 0.001). For those with pCR, 7% have recurred, 0/51 (0%) after IT, 7/17 (41%) after TT. For those without pCR, 34% have recurred, 18/82 (22%) after IT and 19/27 (70%) after TT. 12-month RFS was improved in those with pCR vs without pCR (95% vs 62%, p < 0.001), including in those with IT (100% vs 72%, p < 0.001) and TT (88% vs 43%, p < 0.001). 16 (9%) patients have died including two who had a pCR, both from TT. Conclusions: Neoadjuvant IT and TT are active regimens in resectable clinical stage III melanoma patients and are associated with high pCR rate. The ability to achieve pCR correlates with improved RFS and remarkably no patient with pCR from immunotherapy has recurred to date.

Personalized response-driven adjuvant therapy after combination ipilimumab and nivolumab in high-risk resectable stage III melanoma: PRADO trial

TPS9605

Background: Adjuvant (adj) immune checkpoint inhibition (ICI) improves relapse free survival (RFS) in stage III melanoma patients (pts). However, preclinical and translational data suggest that neo-adjuvant (neoadj) treatment might be favorable due to broader immune activation. The phase 1b OpACIN study comparing neoadj to adj IPI plus NIVO demonstrated a high pathological response rate (pRR) of 78% complicated by 90% gr 3-4 immune-related adverse events (irAEs). The phase 2 OpACIN-neo trial tested safety and efficacy of three different schemes of neoadj IPI+NIVO and identified two cycles of IPI 1mg/kg + NIVO 3mg/kg as well tolerated (20% gr 3-4 irAEs), with a high pRR of 77%. In both trials, none of the pts with a pathologic response have relapsed after a median follow-up of 30 and 8.3 months. In stage IV melanoma, long-term benefit is observed in patients achieving CR with ICI, even after cessation of therapy. This raises the question of whether a therapeutic lymph node dissection (TLND) can be omitted when a deep pathologic response with neoadj IPI+NIVO is achieved. Methods: The aim of this international multi-center investigator-initiated phase 2 PRADO extension study is to confirm the pRR and toxicity of 2 cycles of neoadjuvant IPI 1mg/kg + NIVO 3mg/kg (the preferred OPACIN-neo regimen) and to test response-driven subsequent therapy i.e. omitting surgery and adjuvant ICI based on the pathological response. 100-110 pts with stage IIIB/C melanoma and a measurable lymph node (≥15mm according to RECIST 1.1) will receive two cycles of IPI 1mg/kg + NIVO 3mg/kg after marker placement into the largest lymph node metastasis. After six weeks, pts will undergo resection of the index lymph node. For pCR/near pCR, pts will not undergo TLND; For pPR, pts will undergo TLND; and for pNR, pts will undergo TLND and start adjuvant NIVO or targeted therapy +/- radiotherapy for 52 weeks. Primary endpoints are pRR of marked lymph node and RFS at 24 months. Baseline biopsies, blood samples (week 0, 6, 12) and faeces (week 0, 6) will be collected for translational research analyses. The first patient in this trial was included in October 2018; 22 patients have been enrolled. Clinical trial information: NCT02977052.

Comprehensive molecular profiling of metastatic melanoma to predict response to monotherapy and combination immunotherapy

9511

Background: Several factors have been proposed as biomarkers for response to PD1 therapy, including tumor mutational burden (TMB), immune gene expression, PD-L1 expression and TILs, while few specific mechanisms of resistance have been identified. The relative importance of these factors or detailed examination of biomarkers of response to combination immunotherapy have yet to be explored. Methods: Cutaneous metastatic melanoma (MM) patients (pts) treated with anti-PD-1 (PD1) +/- anti-CTLA-4 (CTLA4) were selected. Pre-treatment tumors underwent whole genome sequencing (WGS), RNA sequencing (RNAseq) and immunohistochemistry (IHC; TILs and PD-L1). Results: Tumors from 77 pts treated with PD1 (n = 53) or PD1+CTLA4 (n = 24) underwent WGS. Higher TMB (p = 0.0001), lower structural variant (SV) burden (p = 0.001) and higher neoantigen load (p = 0.001) were associated with response. There was no difference in the expression of specific genes reported to confer resistance (JAK1/2, PTEN or BAF/PBAF complex members) or response (SERPINB3/4, ARID) in responders vs non-responders. RNAseq was performed on 53/77 samples; IFN and TCR signalling pathways were enriched in responders. Cytolytic activity (CYT, p = 0.002), T cell proportion estimated by CIBERSORT (p = 0.002) and confirmed by IHC (p = 0.033), and PD-L1 expression (IHC, p = 0.026) were also higher in responders. Multivariate analysis including DNA (TMB, SV count), RNA (six gene IFN expression signature - IFNG.6; effector T cell gene expression signature; chemokine gene expression; CYT), IHC (PD-L1, TILs) and clinical factors (sex, age, RECIST Sum of diameters, LDH) identified TMB and IFNG.6 as independent predictors of response (AUC = 0.83). 15 outliers with discordant molecular features and clinical outcomes had varying profiles, including 5 non-responders with high TMB, but low IFNG.6 expression, suggestive of a failure of immune activation. Conclusions: Comprehensive clinical and genomic analysis demonstrated that TMB and IFNG expression independently predict response, suggesting defects in both immune recognition or activation in non-responders.

Abstract OT2-04-03: Examining personalized radiation therapy (EXPERT): A randomised phase III trial of adjuvant radiotherapy vs observation in patients with molecularly characterized luminal A breast cancer

Background

Radiation therapy (RT) after breast conserving surgery (BCS) is the current standard of care for patients with early stage breast cancer. However, individual absolute recurrence risks and hence benefits of RT vary substantially. A study showed significant association between local recurrence (LR) risk and PAM50-defined intrinsic subtypes and Risk of Recurrence scores (ROR).1

The objective of EXPERT, a co-lead study of Breast Cancer Trials-Australia & New Zealand (BCT-ANZ), and Breast International Group (BIG), is to optimize local therapy for early breast cancer through precise individualized quantification of LR risk to identify patients for whom RT after BCS may be safely omitted.

Trial design

This is a randomized, non-inferiority, phase III study of women who plan to receive adjuvant endocrine therapy for Prosigna (PAM50)-defined luminal A breast cancer with ROR ≤60 resected by BCS.

Women are randomized to receive adjuvant whole breast RT and endocrine therapy or endocrine therapy alone and followed-up for 10 years after randomization.

Major eligibility criteria

Females aged ≥50 years; histologically confirmed invasive breast carcinoma ≤2 cm, grade 1 or 2, ER and PgR ≥10%, HER2-negative and node-negative; treated by BCS with negative margins for invasive carcinoma and associated DCIS; Prosigna (PAM50)-defined Luminal A subtype and ROR ≤60; and plan to receive adjuvant endocrine therapy.

Specific aims

Primary: To determine if omission of RT is not inferior to RT in terms of LR-free interval after BCS.

Secondary: To evaluate the impact of omission of RT on regional, local-regional and distant recurrence-free interval; disease-free survival (DFS); invasive DFS; overall survival; salvage RT or mastectomy rate; toxicity; endocrine therapy adherence; patient reported outcomes; and health economic outcomes.

Statistical methods

An estimated 5-year LR rate in the target population is expected to be 1% with RT. A rate of 4% is considered non-inferior as a worthwhile trade-off against RT toxicity. Using O'Brien-Fleming boundary for rejecting non-inferiority, 29 LR events are required for final analysis expected 8 years after the first patient is randomized. Two interim analyses will be conducted after 10 and 21 events. If the stratified log-rank test statistic exceeds the upper boundary at interim or final analysis, the hypothesis of non-inferiority will be rejected and it will be concluded that no RT is inferior to RT.

Accrual: Target (1170), actual: 82 (June 2018)

The study was activated in Australia in August 2017, with global activation planned for Q4 2018. Recruitment is expected to be completed in 4.5 years.

Contact information

Professor Boon Chua, UNSW Sydney and Prince of Wales Hospital, NSW, Australia; email boon.chua@health.nsw.gov.au; T +61 2 49255239. Registration: NCT02889874

References

Fitzal F, Filipits M, Fesl C, et al. Predicting local recurrence using PAM50 in postmenopausal endocrine responsive breast cancer patients. JCO 2014;32(15 suppl):1008.

Citation Format: Chua BH, Gray K, Krishnasamy M, Regan M, Zdenkowski N, Loi S, Mann B, Forbes JF, Wilcken N, Spillane A, Martin A, Badger H, Jafari S, Fong A, Mavin C, Corachan S, Arahmani A, Martinez J-L, Francis P. Examining personalized radiation therapy (EXPERT): A randomised phase III trial of adjuvant radiotherapy vs observation in patients with molecularly characterized luminal A breast cancer [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 OT2-04-03.

Re-examining the role of adjuvant radiation therapy

Previously important roles for adjuvant radiotherapy (RT) in melanoma patients included improved regional control after resection of high-risk nodal disease, to reduce local recurrence for desmoplastic, and other subtypes of melanoma with neurotropism, reducing in-brain relapse of brain metastases after surgery and other situations on a case-by-case basis. This review evaluates the integration of adjuvant RT into clinical practice at this time of rapidly evolving knowledge and improving outcomes from effective systemic therapy.

International validation of the European Organisation for Research and Treatment of Cancer QLQ-BRECON23 quality-of-life questionnaire for women undergoing breast reconstruction

Background

The aim was to carry out phase 4 international field-testing of the European Organisation for Research and Treatment of Cancer (EORTC) breast reconstruction (BRECON) module. The primary objective was finalization of its scale structure. Secondary objectives were evaluation of its reliability, validity, responsiveness, acceptability and interpretability in patients with breast cancer undergoing mastectomy and reconstruction.

Methods

The EORTC module development guidelines were followed. Patients were recruited from 28 centres in seven countries. A prospective cohort completed the QLQ-BRECON15 before mastectomy and the QLQ-BRECON24 at 4–8 months after reconstruction. The cross-sectional cohort completed the QLQ-BRECON24 at 1–5 years after reconstruction, and repeated this 2–8 weeks later (test–retest reliability). All participants completed debriefing questionnaires.

Results

A total of 438 patients were recruited, 234 in the prospective cohort and 204 in the cross-sectional cohort. A total of 414 reconstructions were immediate, with a comparable number of implants (176) and donor-site flaps (166). Control groups comprised patients who underwent two-stage implant procedures (72, 75 per cent) or delayed reconstruction (24, 25 per cent). Psychometric scale validity was supported by moderate to high item-own scale and item-total correlations (over 0·5). Questionnaire validity was confirmed by good scale-to-sample targeting, and computable scale scores exceeding 50 per cent, except nipple cosmesis (over 40 per cent). In known-group comparisons, QLQ-BRECON24 scales and items differentiated between patient groups defined by clinical criteria, such as type and timing of reconstruction, postmastectomy radiotherapy and surgical complications, with moderate effect sizes. Prospectively, sexuality and surgical side-effects scales showed significant responsiveness over time (P &lt; 0·001). Scale reliability was supported by high Cronbach's α coefficients (over 0·7) and test–retest (intraclass correlation more than 0·8). One item (finding a well fitting bra) was excluded based on high floor/ceiling effects, poor test–retest and weak correlations in factor analysis (below 0·3), thus generating the QLQ-BRECON23 questionnaire.

Conclusion

The QLQ-BRECON23 is an internationally validated tool to be used alongside the EORTC QLQ-C30 (cancer) and QLQ-BR23 (breast cancer) questionnaires for evaluating quality of life and satisfaction after breast reconstruction.