Clinical variables associated with immune checkpoint inhibitor outcomes in patients with metastatic urothelial carcinoma: a multicentre retrospective cohort study

OBJECTIVES

Immune checkpoint inhibitors (ICIs) are indicated for metastatic urothelial cancer (mUC), but predictive and prognostic factors are lacking. We investigated clinical variables associated with ICI outcomes.

METHODS

We performed a multicentre retrospective cohort study of 135 patients who received ICI for mUC, 2016-2021, at three Canadian centres. Clinical characteristics, body mass index (BMI), metastatic sites, neutrophil-to-lymphocyte ratio (NLR), response and survival were abstracted from chart review.

RESULTS

We identified 135 patients and 62% had received ICI as a second-line or later treatment for mUC. A BMI ≥25 was significantly correlated to a higher overall response rate (ORR) (45.4% vs 16.3%, p value=0.020). Patients with BMI ≥30 experienced longer median overall survival (OS) of 24.8 vs 14.4 for 25≤BMI<30 and 8.5 months for BMI <25 (p value=0.012). The ORR was lower in the presence of bone metastases (16% vs 41%, p value=0.006) and liver metastases (16% vs 39%, p value=0.013). Metastatic lymph nodes were correlated with higher ORR (40% vs 20%, p value=0.032). The median OS for bone metastases was 7.3 versus 18 months (p value <0.001). Patients with liver metastases had a median OS of 8.6 versus 15 months (p value=0.006). No difference for lymph nodes metastases (13.5 vs 12.7 months, p value=0.175) was found. NLR ≥4 had worse OS (8.2 vs 17.7 months, p value=0.0001). In multivariate analysis, BMI ≥30, bone metastases, NLR ≥4, performance status ≥2 and line of ICI ≥2 were independent factors for OS.

CONCLUSIONS

Our data identified BMI and bone metastases as novel clinical biomarkers that were independently associated with ICI outcomes in mUC. External and prospective validation are warranted.

Key Considerations for the Treatment of Advanced Breast Cancer in Older Adults: An Expert Consensus of the Canadian Treatment Landscape

The prevalence of breast cancer amongst older adults in Canada is increasing. This patient population faces unique challenges in the management of breast cancer, as older adults often have distinct biological, psychosocial, and treatment-related considerations. This paper presents an expert consensus of the Canadian treatment landscape, focusing on key considerations for optimizing selection of systemic therapy for advanced breast cancer in older adults. This paper aims to provide evidence-based recommendations and practical guidance for healthcare professionals involved in the care of older adults with breast cancer. By recognizing and addressing the specific needs of older adults, healthcare providers can optimize treatment outcomes and improve the overall quality of care for this population.

Statins to prevent early cardiac dysfunction in cancer patients at increased cardiotoxicity risk receiving anthracyclines

BACKGROUND AND AIMS

Anthracyclines can cause cancer therapy-related cardiac dysfunction (CTRCD). We aimed to assess whether statins prevent decline in left ventricular ejection fraction (LVEF) in anthracycline-treated patients at increased risk for CTRCD.

METHODS

In this multicenter double-blinded, placebo-controlled trial, patients with cancer at increased risk of anthracycline-related CTRCD (per ASCO guidelines) were randomly assigned to atorvastatin 40 mg or placebo once-daily. Cardiovascular magnetic resonance (CMR) imaging was performed before and within 4 weeks after anthracyclines. Blood biomarkers were measured at every cycle. The primary outcome was post-anthracycline LVEF, adjusted for baseline. CTRCD was defined as a fall in LVEF by >10% to <53%. Secondary endpoints included left ventricular (LV) volumes, CTRCD, CMR tissue characterization, high sensitivity troponin I (hsTnI), and B-type natriuretic peptide (BNP).

RESULTS

We randomized 112 patients (56.9 ± 13.6 years, 87 female, and 73 with breast cancer): 54 to atorvastatin and 58 to placebo. Post-anthracycline CMR was performed 22 (13-27) days from last anthracycline dose. Post-anthracycline LVEF did not differ between the atorvastatin and placebo groups (57.3 ± 5.8% and 55.9 ± 7.4%, respectively) when adjusted for baseline LVEF (P = 0.34). There were no significant between-group differences in post-anthracycline LV end-diastolic (P = 0.20) or end-systolic volume (P = 0.12), CMR myocardial edema and/or fibrosis (P = 0.06-0.47), or peak hsTnI (P ≥ 0.99) and BNP (P = 0.23). CTRCD incidence was similar (4% versus 4%, P ≥ 0.99). There was no difference in adverse events.

CONCLUSIONS

In patients at increased risk of CTRCD, primary prevention with atorvastatin during anthracycline therapy did not ameliorate early LVEF decline, LV remodeling, CTRCD, change in serum cardiac biomarkers, or CMR myocardial tissue changes.

TRIAL REGISTRATION

NCT03186404.

Abstract P3-07-14: A phase II study of CFI-400945 in patients with advanced/metastatic cancer: Canadian Cancer Trials Group (CCTG) IND.237

Background:

CFI-400945 is a selective oral inhibitor of Polo-like Kinase 4 (PLK4), a controller of centriole duplication and mitotic progression identified by functional screening of genomically unstable breast cancer (BC). IND.237 (NCT01954316) is an open label, multicentre, phase 2 study in HER2 negative metastatic breast cancer (MBC) with 3 cohorts, 1 enriched for PTEN loss of function. Enrollment started in 2018 at 64mg based on a previously established recommended phase 2 dose (RP2D). The initial patients had higher than expected grade 3/4 neutropenia which led to a voluntary hold and dose de-escalation; the new RP2D was declared at 32mg as previously reported Here we report the results of the phase 2 study of CFI-400945 in advanced BC patients.

Materials and Methods:

49 patients were enrolled across 3 cohorts: 1: triple negative; 2: ER+/HER2- PTEN low (by IHC); 3: ER+/HER2-, PTEN intact. The primary outcome is objective response rate (ORR); secondary outcomes included disease control rate (DCR) &gt;16w, and safety. A Simon 2-stage design was used (9 – 25 pts planned for each cohort). CFI-400945 would be considered active if ≥3 responses were observed in any given cohort. Eligibility included ECOG 0-1, adequate organ function and receipt of at ≥1 prior line of cytotoxic chemotherapy in any setting including anthracycline taxane (unless contraindicated). Treatment was 32mg 7d on 7d off in cycle 1 (cycle length=28d), then continuously starting cycle 2. Safety assessments were performed each cycle and response (RECIST 1.1) every 2 cycles.

Results:

60 patients have been screened, 49 enrolled: 10 were in initial dose ranging and were excluded from phase 2 response assessment. 10 patients were enrolled in cohort 1, 4 in cohort 2, and 25 in cohort 3. Table 1 presents patient characteristics and response results. 1 patient in cohort 3 has not had disease re-assessed at time of abstract submission. The most common adverse events have been cytopenias, nausea, fatigue, headache, constipation and vomiting. Less than 5% of patients experienced a non-hematologic AE &gt; grade 3; 33% experienced ≥ grade 3 neutropenia.

Conclusions:

CFI-400945 32mg is well tolerated in this MBC population with moderate incidence of uncomplicated neutropenia. The TNBC cohort so this arm has been closed to further accrual for lack of responses. The PTEN loss group has been slow to accrue and remains open. Responses in the ER+/HER2- arm are encouraging – results from patients remaining on study are awaited and correlative studies to identify features associated with responses are underway.

Acknowledgements: Sponsored by the Canadian Cancer Trials Group. Supported by Stand Up To Cancer Canada (scientific partner AACR) Canadian Cancer Society (CCS) Breast Cancer Dream Team Research Funding, Ontario Institute for Cancer Research (funding provided by the Government of Ontario) and grants from CCS to CCTG.

Table 1. Table 1. Patient characteristics and response rates in each cohort treated with CFI-400945.

Citation Format: David W. Cescon, John Hilton, Philippe Bedard, Phillip Blanchette, Rossanna C. Pezo, Ayesha Bashir, Vikaash Kumar, Terry L. Ng, Arif Awan, Anthony Lott, Jacques Antoun Raphael, Linda Hagerman, Mark Bray, Lindsay Muyot, Jesus Fuentes Antras, Lesley Seymour, Dongsheng Tu, Pierre-Olivier Gaudreau, Moira Rushton. A phase II study of CFI-400945 in patients with advanced/metastatic cancer: Canadian Cancer Trials Group (CCTG) IND.237 [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 P3-07-14.

Abstract PD18-10: Treatment of HER2-positive (HER2+) hormone-receptor positive (HR+) metastatic breast cancer (mBC) with the novel combination of zanidatamab, palbociclib, and fulvestrant

Background: HER2+ mBC remains incurable, with a need for new HER2-directed therapies and regimens, including chemotherapy-free options. Zanidatamab (zani) is a novel HER2-targeted bispecific antibody that binds HER2 in a unique trans configuration, driving multiple mechanisms of antitumor activity, including complement-dependent cytotoxicity. A CDK4/6 inhibitor combined with endocrine therapy is an approved treatment for HER2-negative/HR+ mBC and this combination has also demonstrated encouraging antitumor activity when paired with HER2-targeted therapy(ies) in HER2+/HR+ mBC. Here, we report results from ZWI-ZW25-202 (NCT04224272), an ongoing single-arm phase 2 study of zani combined with palbociclib (palbo) and fulvestrant (fulv) in pts with HER2+/HR+ mBC. Methods: Eligibility requirements include: HER2+/HR+ unresectable, locally advanced BC or mBC; ECOG PS of 0 or 1; prior treatment with trastuzumab, pertuzumab and T DM1 (additional prior HER2-targeting agents are permitted); and no prior treatment with CDK4/6 inhibitors. Part 1 of the study evaluated the safety and tolerability of the zani/palbo/fulv combination and determined the recommended doses for use in Part 2, where the antitumor activity of the combination is being evaluated. Endpoints include safety outcomes, progression-free survival at 6 months (PFS6), confirmed objective response rate (cORR) per RECIST v1.1; disease control rate (DCR=complete response [CR] plus partial response [PR] plus stable disease [SD]); duration of response (DOR); PFS; and overall survival. Results: As of 24 Feb 2022, 34 pts (33 HER2+/HR+ per central analysis) with a median age of 52 (range 36-77) have been treated. In the metastatic setting, pts had received a median (range) of 4 (1-10) prior systemic regimens, including 3 (1-8) different prior HER2 targeted therapies, and 1 (0-4) endocrine therapy. Seven pts (20%) had prior T DXd treatment and 7 pts had prior fulv treatment. All pts received zani (20 mg/kg Q2W) and standard doses of palbo and fulv. Eighteen pts (53%) remained on treatment; median duration of zani treatment was 6.9 mo (range 0.5-16.3). A dose-limiting toxicity (DLT) of neutropenia occurred in 1 of 7 DLT-evaluable pts in Part 1. Among all pts (n=34), the most common (&gt;20%) treatment (zani, palbo and/or fulv)-related adverse events (TRAEs) were diarrhea (74%), neutrophil count decreased/neutropenia (62%), stomatitis (41%), asthenia (26%), nausea (24%), and anemia (21%). Grade (Gr) ≥3 TRAEs in 2 or more pts included neutrophil count decreased/neutropenia (50%), anemia (6%), diarrhea (6%), and thrombocytopenia (6%). AEs of special interest were all Gr ≤2 and included 4 pts with cardiac events (LVEF decrease of ≥10% from baseline) and 1 pt with infusion-related reaction. There were no treatment-related serious AEs. Palbo was discontinued for 1 pt due to an AE (AST increase); no pt discontinued zani treatment as a result of AEs. Two deaths occurred: 1 due to disease progression and 1 due to an unrelated AE of pneumonia caused by COVID-19. In 29 pts with measurable disease, the cORR was 34.5% (95% CI: 17.9, 54.3), all responses were cPRs, of which 1 is pending CR confirmation. DOR ranged from 2.3 to 14.9+ mo, with 8 confirmed responses ongoing, and the DCR was 93.1% (95% CI: 77.2, 99.2). Interim median PFS was 11.3 mo (range 0.03-16.7; 95% CI: 5.6, not estimable). PFS6 analysis is planned following the completion of enrollment. Conclusions: Zani in combination with palbo and fulv shows encouraging antitumor activity with durable responses in heavily pretreated pts and a manageable safety profile. This regimen has the potential to be a chemotherapy-free treatment option in pts with HER2+/HR+ mBC. Enrollment in the study is continuing.

Citation Format: Santiago Escrivá-de-Romani, Emilio Alba, Álvaro Rodríguez-Lescure, Sara Hurvitz, Juan Miguel Cejalvo, Maria Gión, Cristiano Ferrario, Manuel Ruiz Borrego, Rossanna C. Pezo, Erika Hamilton, Marc Webster, Timothy Pluard, Muralidhar Beeram, Begoña Jiménez Rodríguez, Hannah Linden, Cristina Saura, Adam Omidpanah, Phoebe Harvey, Marie-France Savard. Treatment of HER2-positive (HER2+) hormone-receptor positive (HR+) metastatic breast cancer (mBC) with the novel combination of zanidatamab, palbociclib, and fulvestrant [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 PD18-10.

Helicobacter pylori serology is associated with worse overall survival in patients with melanoma treated with immune checkpoint inhibitors

The microbiome is now regarded as one of the hallmarks of cancer and several strategies to modify the gut microbiota to improve immune checkpoint inhibitor (ICI) activity are being evaluated in clinical trials. Preliminary data regarding the upper gastro-intestinal microbiota indicated that Helicobacter pylori seropositivity was associated with a negative prognosis in patients amenable to ICI. In 97 patients with advanced melanoma treated with ICI, we assessed the impact of H. pylori on outcomes and microbiome composition. We performed H. pylori serology and profiled the fecal microbiome with metagenomics sequencing. Among the 97 patients, 22% were H. pylori positive (Pos). H. pylori Pos patients had a significantly shorter overall survival (p = .02) compared to H. pylori negative (Neg) patients. In addition, objective response rate and progression-free survival were decreased in H. pylori Pos patients. Metagenomics sequencing did not reveal any difference in diversity indexes between the H. pylori groups. At the taxa level, Eubacterium ventriosum, Mediterraneibacter (Ruminococcus) torques, and Dorea formicigenerans were increased in the H. pylori Pos group, while Alistipes finegoldii, Hungatella hathewayi and Blautia producta were over-represented in the H. pylori Neg group. In a second independent cohort of patients with NSCLC, diversity indexes were similar in both groups and Bacteroides xylanisolvens was increased in H. pylori Neg patients. Our results demonstrated that the negative impact of H. pylori on outcomes seem to be independent from the fecal microbiome composition. These findings warrant further validation and development of therapeutic strategies to eradicate H. pylori in immuno-oncology arena.

The real-world experience of adjuvant docetaxel and cyclophosphamide (TC) chemotherapy in HER-2 negative breast cancer

538

Background: Adjuvant chemotherapy in breast cancer (BC) substantially improves overall survival (OS) and the risk of recurrence. The short and long-term side effects of anthracycline, and its modest benefits in the adjuvant setting, led to controversy about its role in comparison with TC. We aim to compare the OS of TC with anthracycline-based regimens in Ontario, the most populous province in Canada. Methods: We conducted a retrospective population-based cohort study using the Institute for Clinical Evaluative Sciences (ICES) database, involving females with stage I-III BC HER2-negative. Patients were treated with adjuvant chemotherapy between January 2009 to December 2017. The anthracycline regimens for comparison were as follows, FEC-D: Fluorouracil, Epirubicin, Cyclophosphamide, followed by Docetaxel; and ACT: Doxorubicin, Cyclophosphamide, followed by Docetaxel or Paclitaxel. Exclusion criteria included missing baseline characteristics, a prior history of malignancy or chemotherapy starting more than 120 days from breast surgery. The end of follow-up was March 31st, 2018. Adjusted analyses to compare OS by positive axillary lymph nodes (LN) and chemotherapy regimens were conducted with Cox proportional hazards models. Results: Of a total 10634 female patients with BC, 60% were ≥ 50 years-old, with 19.6% stage I, 61.1% stage II, and 19.3% stage III and 7130 (67%) women were classified as ER+ and 2379 (22.4%) as ER-. Among 5764 (54.2%) patients with positive LN, 4300 (40.4%) had LN 1-3 and 1464 (13.8%) had LN ≥ 4. There were 4945 (46.5%) high-grade cases. There were 2487 (23.5%) patients treated with TC, 2981 (28%) with ACT, and 5166 (48.5%) with FEC-D. With a median follow-up of 5.5 years, the OS comparison for the entire study population showed hazard ratio (HR) of TC vs ACT was 1.47 (95% CI 1.14 – 1.90), p = 0.0027 and TC vs FEC-D HR was 1.48 (95% CI 1.18 – 1.86), p = 0.0007. For ER+ patients treated with TC, the OS comparison of LN 1-3 and LN ≥ 4 vs. LN 0 showed HR 1.34 (95% CI 0.81 – 2.21), p = 0.26, and HR 4.29 (95% CI 2.09 – 8.79), p < 0.0001, respectively. For ER+ LN 0 patients, the OS HR of TC vs. ACT was 1.15 (95% CI 0.58 – 2.35), p = 0.67, and TC vs. FEC-D HR was 1.38 (95% CI 0.81 – 2.33), p = 0.23. For ER- patients treated with TC, the OS comparison of LN 1-3 and LN ≥ 4 vs. LN 0 showed HR 1.12 (95% CI 0.42 – 3.01), p = 0.82 and HR 4.41 (95% CI 1.33 – 14.59), p = 0.015, respectively. For ER- LN 0 patients, the OS HR for TC vs. ACT was 2.04 (95% CI 1.09 – 3.81), p = 0.025, and TC vs. FEC-D HR was 2.05 (95% CI 1.08 – 3.90), p = 0.028. Conclusions: Patients treated with adjuvant TC who had four or more axillary LN had significantly lower OS when compared to patients with LN 0. For women with ER- disease, TC demonstrated a significant unfavourable survival outcome when compared to anthracycline-based treatments.

FAM72A antagonizes UNG2 to promote mutagenic repair during antibody maturation

Activation-induced cytidine deaminase (AID) catalyses the deamination of deoxycytidines to deoxyuracils within immunoglobulin genes to induce somatic hypermutation and class-switch recombination1,2. AID-generated deoxyuracils are recognized and processed by subverted base-excision and mismatch repair pathways that ensure a mutagenic outcome in B cells3-6. However, why these DNA repair pathways do not accurately repair AID-induced lesions remains unknown. Here, using a genome-wide CRISPR screen, we show that FAM72A is a major determinant for the error-prone processing of deoxyuracils. Fam72a-deficient CH12F3-2 B cells and primary B cells from Fam72a-/- mice exhibit reduced class-switch recombination and somatic hypermutation frequencies at immunoglobulin and Bcl6 genes, and reduced genome-wide deoxyuracils. The somatic hypermutation spectrum in B cells from Fam72a-/- mice is opposite to that observed in mice deficient in uracil DNA glycosylase 2 (UNG2)7, which suggests that UNG2 is hyperactive in FAM72A-deficient cells. Indeed, FAM72A binds to UNG2, resulting in reduced levels of UNG2 protein in the G1 phase of the cell cycle, coinciding with peak AID activity. FAM72A therefore causes U·G mispairs to persist into S phase, leading to error-prone processing by mismatch repair. By disabling the DNA repair pathways that normally efficiently remove deoxyuracils from DNA, FAM72A enables AID to exert its full effects on antibody maturation. This work has implications in cancer, as the overexpression of FAM72A that is observed in many cancers8 could promote mutagenesis.

MR-guided focused ultrasound enhances delivery of trastuzumab to Her2-positive brain metastases

[Figure: see text].

Gut microbiota signatures are associated with toxicity to combined CTLA-4 and PD-1 blockade

Treatment with combined immune checkpoint blockade (CICB) targeting CTLA-4 and PD-1 is associated with clinical benefit across tumor types, but also a high rate of immune-related adverse events. Insights into biomarkers and mechanisms of response and toxicity to CICB are needed. To address this, we profiled the blood, tumor and gut microbiome of 77 patients with advanced melanoma treated with CICB, with a high rate of any ≥grade 3 immune-related adverse events (49%) with parallel studies in pre-clinical models. Tumor-associated immune and genomic biomarkers of response to CICB were similar to those identified for ICB monotherapy, and toxicity from CICB was associated with a more diverse peripheral T-cell repertoire. Profiling of gut microbiota demonstrated a significantly higher abundance of Bacteroides intestinalis in patients with toxicity, with upregulation of mucosal IL-1β in patient samples of colitis and in pre-clinical models. Together, these data offer potential new therapeutic angles for targeting toxicity to CICB.

Patients' and Oncologists' Knowledge and Expectations Regarding Tumor Multigene Next-Generation Sequencing: A Narrative Review

BACKGROUND

Tumor multigene next-generation sequencing (NGS) is increasingly being offered to cancer patients to guide clinical management and determine eligibility for clinical trials. We undertook a review of studies examining the knowledge and attitudes of patients and oncologists regarding the primary results and potential secondary findings of such testing.

MATERIALS AND METHODS

A search was conducted through the MEDLINE database using the following keywords: "neoplasms" and "molecular sequencing / genome sequencing / tumor profiling / NGS / whole exome sequencing" and "patient / oncologist" and "knowledge / attitudes / satisfaction / experience / evaluation / perspective / practice / preference." Articles meeting the inclusion criteria and additional relevant articles from their references were selected.

RESULTS

From 1,142 publications identified by the search and 9 from references, 21 publications were included in the final review. Patients generally had positive attitudes toward tumor NGS despite relatively little knowledge of test-related genetics concepts, but their expectations often exceeded the reality of low clinical utility. Patients with higher education and greater genetics knowledge had more realistic expectations and a more altruistic view of the role of NGS. Attitudes toward disclosure of secondary findings were highly variable. Oncologists had poor to moderate genomic literacy; they communicated challenges with tempering patient expectations and deciding what information to disclose.

CONCLUSION

Patients considering undergoing tumor NGS should be provided with easily understandable resources explaining the procedure, goals, and probable outcomes, whenever possible based on evidence-based guidelines. Continuing medical education programs on this topic for oncology health care professionals should strive to improve their genomic literacy and instruct them on how to optimally present this information to their patients.

IMPLICATIONS FOR PRACTICE

Oncologists are increasingly offering tumor multigene testing to patients with advanced cancers to guide more "personalized" treatment and/or determine eligibility for clinical trials. However, patients often have inadequate understanding and unrealistic expectations. Oncologists must ensure that they themselves have sufficient knowledge of the benefits and limitations of testing and must provide their patients with appropriate educational resources. Prior to testing, patients should be told the likelihood of finding a mutation in their specific tumor type for which a targeted treatment or clinical trial is available. Patients also need clear information about the possibility and implications of secondary findings.

Abstract PS10-54: Single-centre retrospective study of treatment choices and outcomes of metastatic breast cancer post-progression on the CDK4/6 inhibitor palbobiclib

Background: For Hormonal Receptor positive/HER2 negative (HR+/HER2-) metastatic Breast Cancer (mBC) the optimal treatment post-progression on a CDK4/6 inhibitor is still not defined. We aim to identify real-world patterns of systemic treatment choice following palbociclib use at a large tertiary cancer centre and to determine the outcomes for this patient population.

Methods: We identified HR+/HER2- mBC patients treated with palbociclib between January 2016 and June 2020 using the institutional computerized prescriber order entry (CPOE) system. Patients with a 2nd primary other than breast, male, or with HER 2 overexpression were excluded. Electronic medical records were retrospectively reviewed to determine clinical, pathological characteristics, and treatment patterns. Our primary outcome was Time to Treatment Failure (TTF) for the subsequent treatment, using the Kaplan Meier survival method.

Results: A total of 136 patients were included. At first diagnosis the median age was 52 years; 52% were premenopausal, the most prevalent primary tumor features were ductal histology (79%), and lymph node positive disease (54%). Regarding initial treatment 77% underwent surgery, 52% had adjuvant radiation therapy, 61% had chemotherapy (CT) and 67% had endocrine therapy (ET). The most frequent metastatic sites were bone 70%, liver 36%, and lung 33%. 63 tumors were rebiopsied, in 21 (33.3%) biomarkers had changed. Palbociclib was indicated as 1 Line in 45% of patients, 2 Line 26%, and ≥ 3 Line 27%. The most tolerated dose was 75 mg (44% v 33% tolerating 125 mg). The most prescribed endocrine backbones were AI (66%) and fulvestrant (30%). mTTF was 29.9 mo. (95%CI 12.68-47.11) for 1L, 33.2 mo. (95%CI 22.45-44.08) for 2L, 7.03 mo. (95%CI 2.29-11.76) for ≥ 3L. After a median follow-up of 18.7 mo, 74 patients (54%) had discontinued palbociclib due to progression (46%), toxicity (5%), or death (4%). Sites of progression were liver 37%, bone 29%, pleura 11%, lung 10% and peritoneum 6.5%. 63 patients had subsequent systemic therapy, with mTTF of 5.6 mo. 46 patients (34%) received chemotherapy, 29 patients had capecitabine, mTTF was 4.8 mo. 13 patients (9%) received endocrine therapy, 9 patients had fulvestrant +/- others, mTTF was 8.9 mo. For 5 patients (4%) the subsequent treatment was CDKi-based, 4 patients continued with palbociclib plus another endocrine backbone, mTTF was 16.5 mo. Only 1 patient (.7%) received everolimus-based subsequent treatment, with a TTF 5.6 mo.

Conclusion: In this real-world analysis, we found that palbociclib was most tolerated at 75 mg and most prescribed with an AI. After progression on CDKi, the tendency was to prescribe a chemotherapy-based subsequent line, mainly capecitabine.

Citation Format: Maria Luisa Romero Lagunes, Faisal Sickandar, Alia Thawer, Neda Stjepanovic, Katarzyna Jerzak, Maureen Trudeau, Andrea Eisen, Sonal Gandhi, Ellen Warner, Danilo Giffoni M. M. Mata, Abdullah MA Al-Humiqani, Anthony Lott, Rossanna C Pezo. Single-centre retrospective study of treatment choices and outcomes of metastatic breast cancer post-progression on the CDK4/6 inhibitor palbobiclib [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS10-54.

Abstract OT-09-04: Analysis of genomic alterations in cell free DNA and gut bacterial diversity in metastatic breast cancer (MBC) patients on endocrine therapy: A pilot study

Background: Endocrine therapies have been associated with an overall survival benefit in MBC. However, a majority of patients eventually develop endocrine resistance and the factors associated with short versus long term response to endocrine therapies have not been well defined. These factors include key genomic alterations as well as alterations in steroid metabolism pathways. Gut bacteria play an important role in estrogen metabolism and may thus impact response to endocrine-based therapies. Our study aims to investigate both genomic and gut bacterial profiles in patients treated with endocrine therapies in MBC to further elucidate potential mechanisms of acquired endocrine resistance. Specific Aims: (1) To examine mutational profiles in cell free DNA of ER+/HER2- MBC patients treated with Aromatase Inhibitors (AI) + CDK 4/6 inhibitors to identify common oncogenic alterations associated clinical outcomes. (2) To identify gut bacterial profiles predictive of short versus long term response to endocrine therapy with AI + CDK 4/6 inhibitors. (3) To identify dietary factors associated with clinical outcomes on AI + CDK 4/6 inhibitor treatment. Patients and Methods: This is a prospective pilot study with the aim of collecting blood and fecal samples for biomarker analysis. Patients with advanced ER+/HER2- breast cancer initiating on standard of care first line palliative systemic therapy with an AI in combination with a CDK 4/6 inhibitor will be screened for eligibility. Patients with relapse on prior endocrine therapy or within 6 months of discontinuation of prior adjuvant endocrine therapy as well as patients with a history of inflammatory bowel disease, chronic diarrhea, malabsorption syndromes and prior bowel resection will be excluded. Taxonomic composition of fecal samples will be assessed by 16S rRNA gene microbiota sequencing. A subset of samples will undergo shotgun metagenomic sequencing. Targeted qPCR will be used to quantitate total bacterial density (by 16S rRNA gene qPCR), as well as genus/ species identified from published studies. Molecular alterations in cell free DNA extracted from peripheral blood samples will be analyzed using the Oncomine (ThermoFisher) Breast cfDNA assay. Droplet digital PCR assays will be designed to investigate common hotspot mutations in additional genes of interest. Dietary information will be assessed through standardized food frequency questionnaire administered at the start of treatment. Study outcomes will be mainly exploratory and hypothesis-generating. The sample size of 20 patients was determined in order to formulate an acceptable confidence interval (&gt;95%) and to account for drop-outs and patients with insufficient number or quality of samples. The primary outcome is to compare genomic and gut bacterial profiles in patients with short (&lt;6 months) versus long (≥24 months) time-to-treatment failure (TTF), defined as the time from first treatment on study until the date of treatment discontinuation for whatever reason (including toxicity). Secondary outcomes include overall survival, toxicity and frequency of genomic and bacterial alterations. Expected Results and Conclusions: We have enrolled two patients after an accrual period of 4 months. Detailed analysis of the genomic profiles in cell free DNA and gut bacterial diversity will provide a comprehensive portrait of the molecular and gut bacterial profiles associated with short versus long term responders to endocrine therapy and might shed light on new therapeutic targets.

Citation Format: Rossanna C. Pezo, Andrea Eisen, Sonal Gandhi, Ellen Warner, Katarzyna Jerzak, Maureen Trudeau, Arun Seth. Analysis of genomic alterations in cell free DNA and gut bacterial diversity in metastatic breast cancer (MBC) patients on endocrine therapy: A pilot study [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr OT-09-04.

Quality of adverse event reporting in phase III randomized controlled trials of breast and colorectal cancer: A systematic review

Background

Clinical trial reports often emphasize efficacy over harms, leading to misinterpretation of the risk‐to‐benefit ratio of new therapies. Clear and sufficiently detailed reporting of methods and results is especially important in the abstracts of trial reports, as readers often base their assessment of a trial on such information. In this study, we evaluated the quality of adverse event (AE) reporting and abstract quality in phase III randomized controlled trials (RCTs) of systemic therapies in breast and colorectal cancer.

Methods

Medline, EMBASE, Cochrane Database of RCTs, and Cochrane Database of Systematic Reviews were searched from November 2005 to September 2018. Phase III RCTs evaluating systemic therapies in breast or colorectal cancer were included. Each article was independently reviewed by two investigators using a standardized data extraction form based on guidelines developed by the Consolidated Standards of Reporting Trials (CONSORT) group. Descriptive statistics, bivariate analysis, and multivariable linear regression were used to analyze data. All statistical tests were two‐sided.

Results

Of 166 RCTs identified, 99.4% reported harms in the manuscript body, and 59.6% reported harms in the abstract. Reporting was restricted to severe harms in 15.6% of RCTs. Statistical comparison of AE rates went unreported in 59.0% of studies. Information regarding AEs leading to dose reductions, treatment discontinuations, or study withdrawals went unreported in 59.3%, 18.7%, and 86.8% of studies, respectively. Recently published RCTs (P = .009) and those sponsored at least partially by for‐profit companies (P = .003) had higher abstract quality scores.

Conclusions

Breast and colorectal cancer phase III RCTs inadequately report CONSORT‐compliant AE data. Improved guideline adherence and abstract reporting is required to properly weigh benefits and harms of new oncologic therapies.

Systematic Review Registration Number

CRD42019140673.

Impact of the gut microbiota on immune checkpoint inhibitor-associated toxicities

Immune checkpoint inhibitors (ICIs) have transformed the treatment of patients with advanced cancers. However, the majority of patients do not respond or develop early progressive disease. A substantial number also develop immune-mediated toxicities that may lead to early treatment discontinuation. Gastrointestinal toxicities in the form of diarrhea and colitis are common and may resemble that observed in patients with inflammatory bowel disease (IBD). Alterations in the gut microbiota are thought to play an important role in mediating the intestinal inflammation that is associated with immune-mediated colitis. In this review, the authors' objective is to provide an overview of the gastrointestinal and hepatic toxicities that can be seen with ICIs and discuss the interactions between gut microbiota and the immune response. The authors also highlight the potential role for fecal microbial transfer (FMT) as an approach to improve therapeutic efficacy and decrease toxicity.

Underuse of ECG monitoring in oncology patients receiving QT-interval prolonging drugs

OBJECTIVE

We examined use of ECG monitoring in oncology patients prescribed QT-prolonging drugs.

METHODS

Patients ≥66 years diagnosed with cancer between 2005 and 2011 were identified through the Ontario Cancer Registry and linked to multiple population-based administrative databases to ascertain demographics, comorbidities, prescription drug use, systemic therapy and ECG. QT-prolonging drugs were identified as per drug lists developed by the Arizona Center for Education and Research on Therapeutics. Univariable and multivariable analyses were used to examine factors associated with ECG use in patients on first-line systemic therapy.

RESULTS

A total of 48 236 patients (median age 74; 49% women) received one or more drugs associated with a risk of QT-interval prolongation but only 27% of patients had an ECG performed. Factors associated with more ECG use on multivariable analysis included recent cancer diagnosis (p for trend <0.001 between 2005 and 2011), use of concurrent QT-prolonging drugs (OR=1.15 per each additional QT-prolonging drug, 95% CI 1.12 to 1.17) and the presence of coronary artery disease (OR 1.31; 95% CI 1.25 to 1.38) and heart failure (OR 1.25; 95% CI 1.17 to 1.35). Use of anticancer (OR 0.74; 95% CI 0.70 to 0.79) and antiemetic (OR 0.93; 95% CI 0.88 to 0.99) QT-prolonging drugs was paradoxically associated with less ECG use.

CONCLUSIONS

Our study highlights common use of QT-prolonging drugs and underuse of ECG in oncology patients. Since ECG is an inexpensive, non-invasive and widely available test, it may be readily incorporated in the monitoring of patients for toxicities in routine clinical practice.

Impact of multi-gene mutational profiling on clinical trial outcomes in metastatic breast cancer

Purpose

Next-generation sequencing (NGS) has identified recurrent genomic alterations in metastatic breast cancer (MBC); however, the clinical utility of incorporating routine sequencing to guide treatment decisions in this setting is unclear. We examine the frequency of genomic alterations in MBC patients from academic and community hospitals and correlate with clinical outcomes.

Methods

MBC patients with good performance status were prospectively recruited at the Princess Margaret Cancer Centre (PM) in Canada. Molecular profiling on DNA extracted from FFPE archival tissues was performed on the Sequenom MassArray platform or the TruSeq Amplicon Cancer Panel (TSACP) on the MiSeq platform. Clinical trial outcomes by RECIST 1.1 and time on treatment were reviewed retrospectively.

Results

From January 2012 to November 2015, 483 MBC patients were enrolled and 440 were genotyped. At least one somatic mutation was identified in 46% of patients, most commonly in PIK3CA (28%) or TP53 (13%). Of 203 patients with ≥ 1 mutation(s), 15% were treated on genotype-matched and 9% on non-matched trials. There was no significant difference for median time on treatment for patients treated on matched vs. non-matched therapies (3.6 vs. 3.8 months; p = 0.89).

Conclusions

This study provides real-world outcomes on hotspot genotyping and small targeted panel sequencing of MBC patients from academic and community settings. Few patients were matched to clinical trials with targeted therapies. More comprehensive profiling and improved access to clinical trials may increase therapeutic options for patients with actionable mutations. Further studies are needed to evaluate if this approach leads to improved clinical outcomes.

Electronic supplementary material

The online version of this article (10.1007/s10549-017-4580-2) contains supplementary material, which is available to authorized users.

Noncoding somatic and inherited single-nucleotide variants converge to promote ESR1 expression in breast cancer

Sustained expression of the oestrogen receptor alpha (ESR1) drives two-thirds of breast cancer and defines the ESR1-positive subtype. ESR1 engages enhancers upon oestrogen stimulation to establish an oncogenic expression program¹. Somatic copy number alterations involving the ESR1 gene occur in approximately 1% of ESR1-positive breast cancers^2–5, implying that other mechanisms underlie the persistent expression of ESR1. We report the significant enrichment of somatic mutations within the set of regulatory elements (SRE) regulating ESR1 in 7% of ESR1-positive breast cancers. These mutations regulate ESR1 expression by modulating transcription factor binding to the DNA. The SRE includes a recurrently mutated enhancer whose activity is also affected by a functional inherited single nucleotide variant (SNV) rs9383590 that accounts for several breast cancer risk-loci. Our work highlights the importance of considering the combinatorial activity of regulatory elements as a single unit to delineate the impact of noncoding genetic alterations on single genes in cancer.

Gut microbial metabolism drives transformation of MSH2-deficient colon epithelial cells

The etiology of colorectal cancer (CRC) has been linked to deficiencies in mismatch repair and adenomatous polyposis coli (APC) proteins, diet, inflammatory processes, and gut microbiota. However, the mechanism through which the microbiota synergizes with these etiologic factors to promote CRC is not clear. We report that altering the microbiota composition reduces CRC in APC(Min/+)MSH2(-/-) mice, and that a diet reduced in carbohydrates phenocopies this effect. Gut microbes did not induce CRC in these mice through an inflammatory response or the production of DNA mutagens but rather by providing carbohydrate-derived metabolites such as butyrate that fuel hyperproliferation of MSH2(-/-) colon epithelial cells. Further, we provide evidence that the mismatch repair pathway has a role in regulating β-catenin activity and modulating the differentiation of transit-amplifying cells in the colon. These data thereby provide an explanation for the interaction between microbiota, diet, and mismatch repair deficiency in CRC induction. PAPERCLIP:

Altered dynamics of intestinal cell maturation in Apc1638N/+ mice

Novel imaging of active transcription sites in interphase nuclei of intestinal epithelial cells in situ showed that key genes associated with Wnt and Notch signaling were dynamically regulated as the cells underwent normal maturation during their migration along the mouse crypt-villus axis (CVA). However, oscillating patterns of activation of these genes were displaced along this axis in the histologically normal intestinal mucosa of Apc(1638N/+) mice before tumor development. Gene expression profiling then showed that the normal reprogramming of cells along the CVA was dampened in the Apc(1638N/+) mice, with an overrepresentation of c-myc target genes among those loci affected in the mutant mice. Moreover, in the Apc(1638N/+) mice, there was a perturbed pattern of expression of lineage-specific markers along the CVA consistent with transcription site repression of the Math1 gene, and genes encoding enzymes of every step of the tricarboxylic acid cycle were downregulated in the crypt of Apc(1638N/+) mice compared with WT, but not in the villus. These changes may alter energy metabolism and generate a pseudohypoxic state, suggested by elevated expression of Hif1alpha and its target genes. Thus, although intestinal tumors develop in Apc(1638N/+) mice on focal loss or inactivation of the WT allele, our results show that in the Apc(1638N/+) mouse, inheritance of only a single WT Apc allele perturbs the dynamic and complex reprogramming underlying normal cell maturation, which links epithelial function and homeostasis with architectural organization of the intestine.

Nuclear microenvironment in cancer diagnosis and treatment

The nuclear architecture plays an important role in the temporal and spatial control of complex functional processes within the nucleus. Alterations in nuclear structures are characteristic of cancer cells and the mechanisms underlying these perturbations may directly contribute to tumor development and progression. In this review, we will highlight aspects of the nuclear microenvironment that are perturbed during tumorigenesis and discuss how a greater understanding of the role of nuclear structure in the control of gene expression can provide new options for cancer diagnosis and treatment.

Single-cell transcription site activation predicts chemotherapy response in human colorectal tumors

Candidate gene and pathway approaches, and unbiased gene expression profiling, have identified marker signatures predictive of tumor phenotypes, such as drug sensitivity and invasive or metastatic potential. However, application of such information to evaluation of tumors in the clinic is limited by cell heterogeneity in the tumor. We have developed a novel method of fluorescence in situ hybridization (FISH) that can detect transcriptional activation of individual genes at their site in single cells in the interphase nucleus. A major obstacle in the treatment of colorectal cancer is relative insensitivity to the chemotherapeutic agent 5-Fluorouracil (5-FU). Here, we have developed a sensitive approach to predict relative sensitivity of colorectal cancer cells to 5-FU, using FISH with probes targeted to nascent mRNAs to measure the number of individual cells with active transcription sites for a panel of candidate genes. These results reveal that the transcriptional status of four key genes, thymidylate synthase (TYMS), MORF-related gene X (MRGX), Bcl2-antagonist/killer (BAK), and ATPase, Cu(2+) transporting beta polypeptide (ATP7B), can accurately predict response to 5-FU. As proof of principle, we show that this transcriptional profile is predictive of response to 5-FU in a small number of patient colon tumor tissues. This approach provides a novel ability to identify and characterize unique minor cell populations in the tumor that may exhibit relative resistance to chemotherapy.

Novel detection and differential utilization of a c-myc transcriptional block in colon cancer chemoprevention

Mutations in the adenomatous polyposis coli (APC) gene, which initiate almost all human colon cancers, directly target the proto-oncogene, c-myc, by elevating beta-catenin/T-cell factor (TCF) signaling. We have shown that agents ascribed chemopreventive activity for colon cancer in fact also stimulate beta-catenin/TCF activity in vitro. Their effects on c-myc transcription were assayed using a novel variant of fluorescence in situ hybridization that detects c-myc transcription sites in intact nuclei. Increased transcriptional initiation of c-myc induced by the short-chain fatty acid, butyrate, consistent with elevated beta-catenin/TCF activity, was efficiently abrogated by a block to transcriptional elongation, resulting in decreased c-myc expression. 1alpha,25-Dihydroxyvitamin D(3) also induced transcriptional blockage. In contrast, the nonsteroidal anti-inflammatory drug, sulindac, increased c-myc expression, an effect attributable at least in part to its failure to induce transcriptional blockage. We have described a novel approach for evaluating the effects of chemopreventive agents on the expression of a gene critical in colonic tumorigenesis.

Single-cell gene expression profiling

A key goal of biology is to relate the expression of specific genes to a particular cellular phenotype. However, current assays for gene expression destroy the structural context. By combining advances in computational fluorescence microscopy with multiplex probe design, we devised technology in which the expression of many genes can be visualized simultaneously inside single cells with high spatial and temporal resolution. Analysis of 11 genes in serum-stimulated cultured cells revealed unique patterns of gene expression within individual cells. Using the nucleus as the substrate for parallel gene analysis, we provide a platform for the fusion of genomics and cell biology: "cellular genomics."