Characteristics and outcomes of immunotherapy-related liver injury in patients with hepatocellular carcinoma versus other advanced solid tumours

BACKGROUND & AIMS

Immune-related liver injury (irLI) is commonly observed in patients with cancer treated with immune checkpoint inhibitors (ICIs). We aimed to compare the incidence, clinical characteristics, and outcomes of irLI between patients receiving ICIs for hepatocellular carcinoma (HCC) vs. other solid tumours.

METHODS

Two separate cohorts were included: 375 patients with advanced/unresectable HCC, Child-Pugh A class treated with first-line atezolizumab+bevacizumab from the AB-real study, and a non-HCC cohort including 459 patients treated with first-line ICI therapy from the INVIDIa-2 multicentre study. IrLI was defined as a treatment-related increase of aminotransferase levels after exclusion of alternative aetiologies of liver injury. The incidence of irLI was adjusted for the duration of treatment exposure.

RESULTS

In patients with HCC, the incidence of any grade irLI was 11.4% over a median treatment exposure of 4.4 months (95% CI 3.7-5.2) vs. 2.6% in the INVIDIa-2 cohort over a median treatment exposure of 12.4 months (95% CI 11.1-14.0). Exposure-adjusted-incidence of any grade irLI was 22.1 per 100-patient-years in patients with HCC and 2.1 per 100-patient-years in patients with other solid tumours (p <0.001), with median time-to-irLI of 1.4 and 4.7 months, respectively. Among patients who developed irLI, systemic corticosteroids were administered in 16.3% of patients with HCC and 75.0% of those without HCC (p <0.001), and irLI resolution was observed in 72.1% and 58.3%, respectively (p = 0.362). In patients with HCC, rates of hepatic decompensation and treatment discontinuation due to irLI were 7%. Grade 1-2 irLI was associated with improved overall survival only in patients with HCC (hazard ratio 0.53, 95% CI 0.29-0.96).

CONCLUSIONS

Despite higher incidence and earlier onset, irLI in patients with HCC is characterised by higher rates of remission and lower requirement for corticosteroid therapy (vs. irLI in other solid tumours), low risk of hepatic decompensation and treatment discontinuation, not negatively affecting oncological outcomes.

IMPACT AND IMPLICATIONS

Immune-related liver injury (irLI) is common in patients with cancer receiving immune checkpoint inhibitors (ICIs), but whether irLI is more frequent or it is associated with a worse clinical course in patients with hepatocellular carcinoma (HCC), compared to other tumours, is not known. Herein, we compared characteristics and outcomes of irLI in two prospective cohorts including patients treated with ICIs for HCC or for other oncological indications. irLI is significantly more common and it occurs earlier in patients with HCC, also after adjustment for duration of treatment exposure. However, outcomes of patients with HCC who developed irLI are not negatively affected in terms of requirement for corticosteroid therapy, hepatic decompensation, treatment discontinuation and overall survival.

Divarasib plus cetuximab in KRAS G12C-positive colorectal cancer: a phase 1b trial

KRAS G12C mutation is prevalent in ~4% of colorectal cancer (CRC) and is associated with poor prognosis. Divarasib, a KRAS G12C inhibitor, has shown modest activity as a single agent in KRAS G12C-positive CRC at 400 mg. Epidermal growth factor receptor has been recognized as a major upstream activator of RAS-MAPK signaling, a proposed key mechanism of resistance to KRAS G12C inhibition in CRC. Here, we report on divarasib plus cetuximab (epidermal growth factor receptor inhibitor) in patients with KRAS G12C-positive CRC (n = 29) from arm C of an ongoing phase 1b trial. The primary objective was to evaluate safety. Secondary objectives included preliminary antitumor activity. The safety profile of this combination was consistent with those of single-agent divarasib and cetuximab. Treatment-related adverse events led to divarasib dose reductions in four patients (13.8%); there were no treatment withdrawals. The objective response rate was 62.5% (95% confidence interval: 40.6%, 81.2%) in KRAS G12C inhibitor-naive patients (n = 24). The median duration of response was 6.9 months. The median progression-free survival was 8.1 months (95% confidence interval: 5.5, 12.3). As an exploratory objective, we observed a decline in KRAS G12C variant allele frequency associated with response and identified acquired genomic alterations at disease progression that may be associated with resistance. The manageable safety profile and encouraging antitumor activity of divarasib plus cetuximab support the further investigation of this combination in KRAS G12C-positive CRC.ClinicalTrials.gov identifier: NCT04449874.

Molecular Subtypes and Outcomes in a Multi-Institutional Review of Rectal Cancer Patients

PURPOSE/OBJECTIVE(S)

Colorectal cancer (CRC) is a heterogeneous malignancy associated with a variety of genetic mutations. More recent data indicates that CRC can be broken down into unique biologically distinct consensus molecular subtypes (CMS) based on different pathological and genetic signatures. The purpose of this study is to evaluate the outcomes of rectal cancer patients in a multi-institutional network based on tumor mutational assessment and CMS group.

MATERIALS/METHODS

Patient exome and transcriptome sequencing data and clinical outcomes were collected under the Total Cancer Care Protocol and Avatar® project within the Oncology Research Information Exchange Network (ORIEN). A total of 101 patients with demographic and outcomes information had data for microsatellite instability (MSI), tumor mutation burden (TMB), transcriptome, and whole exome sequencing (WES). Molecular subclasses (CMS1, CMS2, CMS3, CMS4, CMS-Mixed) were assigned based on transcriptional signatures by the R package "CMS Caller." Survival analysis was performed with the R packages "Survival" and "Survminer."

RESULTS

A total of 101 rectal cancer patients, with a median age of 56.8, had a median follow up of 3.5 years (range 0.26-23.5). 78 patients were treated with curative intent for clinically localized disease and 35% of these patients developed metastatic disease. The remaining 23 patients had synchronous metastatic disease at presentation. There were 5 (5%) CMS1, 29 (29%) CMS2, 13 (13%) CMS 3, 49 (49%) CMS 4, and 5 (5%) CMS-Mixed patients in our cohort respectively. The cohort included 5 (5%) BRAF, 51 (50%) KRAS, and 63 (62%) TP53 mutated patients and 5 (5%) MSI high patients. Median survival was 18.8, 117.2, 125.7 and 119 months for CMS1, CMS2, CMS3, and CMS4 patients respectively, with insufficient events in CMS-mixed for calculation (p = 0.15). CMS1 patients had a significantly shorter survival compared to the other cohorts (p = 0.02), with 2 of 5 of these patients having received immunotherapy. 40% (2,0) CMS1, 52% (7,8) of CMS2, 15% (1,1) of CMS3, 59% (13,15) of CMS4, and 40% (1,1) of CMS-Mixed presented with or developed metastatic disease respectively. When divided into mutation groups, median survival was 43 versus 119, 119 versus 117, and 126 versus 119 months for BRAF, KRAS, and TP53 mutated and wild type patients respectively (p = 0.18, p = 0.48, p = 0.93). Evaluation of TMB and MSI status did not reveal significant differences in outcomes (p = 0.54, p = 0.7), with median survival of 126 months versus 117 in TMB high versus low patients and unreached versus 119 months in MSI versus MSS patients respectively. Of note, 3 of the 5 MSI patients were also CMS1, with the other two coming from CMS4 and CMS-mixed cohorts.

CONCLUSION

CMS classification and tumor mutation status are associated with differential outcomes for rectal cancer patients, with some groups having a large likelihood of developing metastatic disease. Further work on optimizing and personalizing treatments for these high-risk populations is necessary.

Phase Ia/b, Open-Label, Multicenter Study of AZD4635 (an Adenosine A2A Receptor Antagonist) as Monotherapy or Combined with Durvalumab, in Patients with Solid Tumors

PURPOSE

To evaluate AZD4635, an adenosine A2A receptor antagonist, as monotherapy or in combination with durvalumab in patients with advanced solid tumors.

PATIENTS AND METHODS

In phase Ia (dose escalation), patients had relapsed/refractory solid tumors; in phase Ib (dose expansion), patients had checkpoint inhibitor-naïve metastatic castration-resistant prostate cancer (mCRPC) or colorectal carcinoma, non-small cell lung cancer with prior anti-PD-1/PD-L1 exposure, or other solid tumors (checkpoint-naïve or prior anti-PD-1/PD-L1 exposure). Patients received AZD4635 monotherapy (75-200 mg once daily or 125 mg twice daily) or in combination with durvalumab (AZD4635 75 or 100 mg once daily). The primary objective was safety; secondary objectives included antitumor activity and pharmacokinetics; exploratory objectives included evaluation of an adenosine gene signature in patients with mCRPC.

RESULTS

As of September 8, 2020, 250 patients were treated (AZD4635, n = 161; AZD4635+durvalumab, n = 89). In phase Ia, DLTs were observed with monotherapy (125 mg twice daily; n = 2) and with combination treatment (75 mg; n = 1) in patients receiving nanosuspension. The most common treatment-related adverse events included nausea, fatigue, vomiting, decreased appetite, dizziness, and diarrhea. The RP2D of the AZD4635 capsule formulation was 75 mg once daily, as monotherapy or in combination with durvalumab. The pharmacokinetic profile was dose-proportional, and exposure was adequate to cover target with 100 mg nanosuspension or 75 mg capsule once daily. In patients with mCRPC receiving monotherapy or combination treatment, tumor responses (2/39 and 6/37, respectively) and prostate-specific antigen responses (3/60 and 10/45, respectively) were observed. High versus low blood-based adenosine signature was associated with median progression-free survival of 21 weeks versus 8.7 weeks.

CONCLUSIONS

AZD4635 monotherapy or combination therapy was well tolerated. Objective responses support additional phase II combination studies in patients with mCRPC.

Abstract CT254: A first-in-human phase 1 study of the safety and pharmacokinetics of XB002 in patients with inoperable locally advanced or metastatic solid tumors

Background: XB002 is an antibody drug conjugate (ADC), with a high affinity human mAb directed against tissue factor (TF) conjugated to a novel cytotoxic agent (payload), ZLA (Zymelink Auristatin). TF is a protein overexpressed in many solid tumors and is associated with disease progression and poor prognosis. XB002 binds to TF without interfering with the coagulation pathway. With its mechanism of action, XB002 has been designed to improve the therapeutic potential of ADCs targeting TF and has demonstrated activity in several solid tumor xenograft models. The purpose of this ongoing first-in-human study is to evaluate the safety, tolerability, pharmacokinetics (PK), immunogenicity (anti-drug antibodies) and preliminary antitumor activity of XB002. Presented here is the trial design.

Methods: This is a phase 1, non-randomized, open-label, multicenter, dose-escalation and dose expansion study (NCT04925284). Patients must be ≥18 years old and have an ECOG performance status of 0-1 and adequate organ and marrow function. Patients will be treated until radiographic progression per Response Evaluation Criteria in Solid Tumors (RECIST v1.1) or unacceptable toxicity. The dose-escalation stage will use a modified i3+3 design; patients with advanced solid tumors (~21 patients) will receive XB002 IV once every 3 weeks. The primary endpoint for dose escalation is the maximum tolerated dose (MTD)/recommended dose (RD) of XB002 per Cohort Review Committee. The MTD/RD will be further evaluated in multiple tumor-specific expansion cohorts of advanced solid tumors (~30 patients per cohort) using a Simon’s 2-stage design. Tumor-specific cohorts (number of prior lines of systemic therapy for advanced disease) include: non-small cell lung cancer (≤3); urothelial cancer (≤3); platinum-resistant epithelial ovarian cancer (≤3); cervical cancer (≤2); squamous cell carcinoma of head and neck (≤3); and pancreatic cancer (1-2). Patients must have measurable disease per RECIST v1.1 and had radiographic progression during or after their last systemic therapy. The primary endpoint for cohort expansion is objective response rate per RECIST v1.1 by investigator. Additional endpoints include safety/tolerability, XB002 pharmacokinetics and immunogenicity, duration of response and PFS per RECIST v1.1 by investigator, overall survival, and changes in tumor markers from baseline.

Citation Format: Melissa Johnson, Susanna Ulahannan, Andrae Vandross, Haeseong Park, Leo Faoro, Raffaella Faggioni, Jing Li, Yu-Lin Chang, Shailaja Uttamsingh, Anthony Tolcher. A first-in-human phase 1 study of the safety and pharmacokinetics of XB002 in patients with inoperable locally advanced or metastatic solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT254.

480 A first-in-human phase I dose-escalation trial of the B7-H6/CD3 T-cell engager BI 765049 ± ezabenlimab (BI 754091) in patients with advanced solid tumors expressing B7-H6

Background

B7-H6 is a member of the B7 family of immune receptors, which is expressed in several solid tumor types but very little expression can be detected in normal tissues.1 2 BI 765049 is a novel IgG-like bispecific T-cell engager designed to bind simultaneously to B7-H6 on tumor cells and CD3 on T cells, resulting in cytolytic synapse formation and tumor lysis. Preclinical studies have demonstrated that BI 765049 monotherapy induced dose-dependent anti-tumor activity in humanized in vivo CRC tumor models. Consistent with the mode of action, the treatment with BI 765049 led to target cell apoptosis, local T-cell activation/proliferation and cytokine production in the tumor tissue, with PD-(L)1 upregulation.3 Activation of the PD-(L)1 provides the rationale for combining BI 765049 with a PD1 inhibitor.

Methods

NCT04752215 is a first-in-human, open-label, dose-escalation trial of BI 765049 ± the PD-1 inhibitor, ezabenlimab. Adults with advanced, unresectable and/or metastatic CRC, NSCLC, HNSCC, hepatocellular, gastric or pancreatic carcinoma are eligible. Patients must have failed on, or be ineligible, for standard therapies. B7-H6 positivity must be confirmed at screening by central review (immunohistochemistry assay) in archived tissues/in-study fresh biopsies (except CRC). Patients must have ≥1 evaluable lesion (modified RECIST 1.1) outside of the central nervous system and adequate organ function. The primary objective is to determine the maximum tolerated dose (MTD) or recommended dose for expansion of BI 765049 ± ezabenlimab, based on dose-limiting toxicities during the MTD evaluation period. Further objectives are to evaluate safety, tolerability, PK/PD and preliminary efficacy of BI 765049 ± ezabenlimab. The trial may assess up to 4 dosing regimens: A (BI 765049 once every 3 weeks [q3w]); B1 (BI 765049 qw); B2 (BI 765049 qw with step-in doses); C (BI 765049 + ezabenlimab [q3w]). Dose escalation will be guided by a Bayesian Logistic Regression Model with overdose control that will be fitted to binary toxicity outcomes using a hierarchical modelling approach to jointly model all dosing regimens. Treatment will be allowed to continue until confirmed progressive disease, unacceptable toxicity, other withdrawal criteria or for a maximum duration of 36 months, whichever occurs first. Approximately 150–175 patients will be screened and ~120 patients enrolled. As of July 2021, patients are being recruited in early dose-escalation cohorts.

Acknowledgements

Medical writing support for the development of this abstract, under the direction of the authors, was provided by Becky O’Connor, of Ashfield MedComms, an Ashfield Health company, and funded by Boehringer Ingelheim.

Trial Registration

NCT04752215

References

Brandt et al. J Exp Med 2009;206:1495–503.

Boehringer Ingelheim. Data on file.

Hipp et al. AACR Annual Meeting 2021.

Ethics Approval

The trial will be carried out in compliance with the protocol, the ethical principles laid down in the Declaration of Helsinki, in accordance with the ICH Harmonized Guideline for Good Clinical Practice (GCP) and the EU directive 2001/20/EC/EU regulation 536/2014.

369 Clinical update of VT1021, a first-in-class CD36 and CD47 targeting immunomodulating agent, in subjects with pancreatic cancer and other solid tumors stratified by novel biomarkers

Background

One barrier to treating pancreatic cancer is the immunosuppressive tumor microenvironment (TME). VT1021 is a cyclic peptide derived from prosaposin and stimulates thrombospondin-1 (Tsp-1) production in myeloid derived suppressor cells. Tsp-1 binds to CD36 on macrophages to convert M2 macrophages to anti-tumorigenic M1 macrophages; on tumor cells to induce apoptosis; and increases the CD8+/Treg ratio. Tsp-1 also binds to CD47 on tumor cells to block the ”do not eat me signal”. In a recently completed phase I/II clinical study (NCT03364400), VT1021 had no major adverse events and a predictable pharmacokinetic profile.

Methods

To evaluate potential predictive biomarkers of VT1021, CD36/CD47 levels were analyzed on pre-treatment biopsy samples and on-study tumor biopsies collected during the treatment using immunohistochemistry (IHC). Samples were stained and scored by software-based image analysis and manual review (figure 1). Induction of Tsp-1 in circulating peripheral blood mononuclear cells (PBMCs) by ELISA was correlated with Tsp-1 induction in on-study biopsy samples via IHC, and with clinical responses. To be considered ”evaluable”, subjects completed ≥1 cycle of VT1021 treatment and tumor imaging during cycle 2.

Results

In the pancreatic cancer expansion study, 21 of 32 enrolled subjects (66%) had dual high (DH) expression of CD36/CD47. There were 5 subjects with stable diseases among 15 evaluable subjects with disease control rate of 33%. Of the 13 subjects with measurable disease, all 5 subjects with reduction of tumor burden were DH CD36/CD47 and remained on study for an average of 105 days. Moreover, paired tumor biopsies revealed increased Tsp-1 expression, CTL infiltration and M1:M2 ratio among subjects that obtained disease control with DH baseline CD36/CD47 expression.To identify other solid tumor indications that could benefit from VT1021 treatment based on CD36/CD47 expression, commercially available tumor tissue microarrays from 16 different indications were evaluated. Several indications demonstrated high percentage of DH CD36/CD47, including gastric (59%), head and neck (57%), and pancreatic cancers (56%).

Abstract 369 Figure 1

Expression intensities of CD36/CD47 in subjects with pancreatic cancer

Conclusions

Pancreatic cancer subjects who were DH for CD36/CD47 were more likely to have a reduction in tumor burden and stay on study longer than non-DH subjects. Increased Tsp-1 induction in circulating PBMCs and in the TME was confirmed. Remodeling of the TME by VT1021 to be more immune sensitive via CTL and M1 accumulation was demonstrated. Based on these findings, the DH expression of CD36/CD47 could be a useful predictive biomarker to stratify subjects for inclusion in future trials in pancreatic cancer, and in other solid tumor indications.

Trial Registration

Trial Registration

NCT03364400

518 First-in-human results with the novel tumor-targeting antibody ATRC-101: phase 1b study in patients with solid tumors

Background

ATRC-101 is an engineered version of an immunoglobulin G1 antibody that was discovered in a patient with non-small cell lung cancer (NSCLC) experiencing stable disease while being treated with anti–programmed death-1 therapy. ATRC-101 targets a tumor-specific ribonucleoprotein complex containing polyadenylate binding protein-1, which has been found to be present in the majority of NSCLC, acral melanoma, breast, colorectal, and ovarian cancer samples tested. Target immunoreactivity and single-agent activity have been observed in mouse models. Preclinical data suggest that ATRC-101 stimulates both innate and adaptive immune activity against tumors.

Methods

ATRC-101-A01 is a phase 1b trial (3+3 dose escalation with expansion cohorts) in patients with solid tumors treated with ATRC-101 monotherapy every 2 or 3 weeks (Q2W or Q3W), or ATRC-101 in combination with pembrolizumab, until unacceptable toxicity or disease progression at doses of 0.3–30 mg/kg, pending dose-limiting toxicities. The primary objective is safety and secondary objectives are to characterize the pharmacokinetic profile, immunogenicity, and anti-tumor activity of ATRC-101, and to determine the recommended dose for expansion. Pharmacodynamic studies will also be performed to evaluate changes from baseline in specific immune cell populations and cytokine levels in blood and tumors. Results from the ATRC-101 0.3–30 mg/kg monotherapy Q3W cohorts are presented in this abstract (data cutoff: July 16, 2021).

Results

Twenty-four participants with solid tumors (13 colorectal, 5 ovarian, 3 breast, 2 NSCLC, 1 acral melanoma) aged 27–75 years with a median 5 lines of prior therapy were treated Q3W in five dose cohorts. No dose-limiting toxicities were observed. Eight participants (33%) experienced grade ≥3 treatment-emergent adverse events. The maximum serum concentration of ATRC-101 and treatment exposure appeared to be dose proportional. Stable disease was observed in eight patients and best response per RECIST v1.1 was associated with expression of the ATRC-101 target. Multiple biomarkers, such as treatment-associated changes in the composition of CD3+, CD4+, and CD8+ T cells in the blood, and serum cytokines/chemokines, including those predicted to activate antigen-presentation pathways, support the proposed mechanism of action of ATRC-101 and will be presented.

Conclusions

These first-in-human data suggest a manageable safety profile for ATRC-101 Q3W, with no dose-limiting toxicities observed. Pharmacokinetics appear to be dose proportional. Enrollment in the Q2W monotherapy dose-escalation cohort and at the 30 mg/kg dose level Q3W is continuing. Trial sites have been activated to test ATRC-101 in combination with pembrolizumab, and combination with chemotherapy is also planned.

Trial Registration

Trial Registration:

NCT04244552

Ethics Approval

This study was approved by the institutional review board or ethics committee as required for each participating site.

Abstract LB050: Modulation of innate and adaptive immunity in blood and tumor of patients receiving the SHP2 inhibitor RMC-4630

RMC-4630 is a potent, selective, orally bioavailable allosteric inhibitor of SHP2, a central node in the RAS signaling pathway. In preclinical models, SHP2 inhibition not only directly inhibited tumor growth through suppression of tumor-intrinsic RAS signaling, but also resulted in transformation of the tumor immune microenvironment, characterized by an increase in CD8+T cell infiltrates and selective depletion of pro-tumorigenic M2 macrophages.

In this study, we evaluated pharmacodynamic biomarkers in blood and tumors from patients in the RMC-4630 phase I monotherapy clinical trial (NCT 03634982) by using flow cytometry and immunohistochemistry (IHC). Safety, PK and efficacy data are reported in a separate abstract.

Longitudinal analysis of immune cell phenotyping in blood was conducted in 35 patients. There was a trend for lower pre-study monocytic myeloid-derived suppressor cell (mMDSC) to be associated with a better clinical outcome on RMC-4630 therapy. While the proportion of circulating T cell and B cell populations did not change, both blood mMDSC and total monocytes were significantly reduced during RMC-4630 administration. Furthermore, tumor volumes changes, and the proportion of patients with SD versus PD, positively correlated with the ratio of mMDSCs to total monocytes on RMC-4630 treatment.

Inhibition of pERK was observed in a subset of patients. Three paired tumor biopsies from efficacy-evaluable patients, including 1 PR, 1 SD and 1 PD, were available for tumor microenvironment analysis by multiplexed-IHC assays. Increase in tumor infiltrating T cells in the tumors of one patient with a PR and another with SD was observed on RMC-4630 therapy. Inhibition of tumor PD-L1 expression and a decrease in M2 macrophages was also observed on treatment in the tumor biopsy of the PR patient.

Collectively, the preliminary clinical biomarker data supports the preclinical observations that SHP2 inhibition with RMC-4630 modulates both innate and adaptive anti-tumor immunity.

Citation Format: Ariel Yung-Chia Chen, Eric Haura, Jose Pacheco, Marianna Koczywas, Michael Gordon, Susanna Ulahannan, Howard A. Burris, Sai-Hong Ignatius Ou, Judy S. Wang, Jonathan W. Riess, Caroline McCoach, Anna Capasso, Elsa Quintana, Josie Hayes, Richa Dua, Bojena Bitman, Martha Guerra, Hongfang Wang, Xiaolin Wang, Pasi A. Janne. Modulation of innate and adaptive immunity in blood and tumor of patients receiving the SHP2 inhibitor RMC-4630 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr LB050.

Abstract LB054: Confirmation of target inhibition and anti-tumor activity of the SHP2 inhibitor RMC-4630 via longitudinal analysis of ctDNA in a phase 1 clinical study

RMC-4630 is a potent, selective, orally bioavailable allosteric inhibitor of SHP2, a central node in the RAS signaling pathway. Preclinical data have demonstrated that RMC-4630 can shrink tumors carrying certain mutations in the RAS pathway such as KRASG12C, NF1LOF, and BRAFClass3. Longitudinal circulating tumor DNA (ctDNA) was isolated from blood using GuardantOMNI in 80 patients with relapsed/refractory solid tumors in the phase 1 dose-escalation trial of RMC-4630 (NCT03634982) to characterize and confirm RAS pathway mutations and to evaluate molecular responses in patients receiving RMC-4630 monotherapy. Safety, PK and efficacy findings from this study are reported in a separate abstract. 78 of 80 patients had baseline somatic mutations detected in plasma, of which 60 were either KRASG12X, NF1LOF, or BRAFClass3; 48 of these 60 patients also had on-treatment ctDNA assessments and these patients constitute the population reported here. 9 of 48 patients (19%) had KRASG12C detected at baseline, available scan results and a ctDNA sample after 4 weeks of receiving RMC-4630. A decrease in KRASG12C variant allele frequency (VAF) was detected in 5/9 patients (56%) with clearance in 1 patient with a partial response. Decrease in KRASG12C VAF was associated with change in tumor volume (PCC=0.85, p=0.008), preceding scan results by approximately 1 month, suggesting that change in KRASG12C VAF may be an early measure of drug activity or possibly response. 5 of 48 patients (10%) had NF1LOF detected at baseline. A decrease, or stability in NF1LOF VAF on treatment compared to baseline was detected in 4 (80% of all NF1LOF patients). The decrease in NF1LOF VAF was not associated with change in tumor volume and may represent effects of RMC-4630 on a subclone harboring NF1LOF. One patient had a detectable BRAFClass3 mutation at baseline, which decreased in VAF on treatment compared to baseline. Of the remaining patients there were 12 KRASG12D, 9 KRASG12V and other KRASG12X. The majority progressed with an increase in VAF of all mutations including KRASG12X, suggesting that the KRASG12X-containing clone is responsible for escape from single agent RMC-4630. In most instances the increase in KRASG12X VAF in blood preceded determination of clinical progression. Longitudinal assessment of ctDNA indicates that some patients with RAS-addicted tumors undergo a molecular response on treatment with the SHP2 inhibitor RMC-4630.

Citation Format: Josie L. Hayes, Marianna Koczywas, Sai-Hong Ignatius Ou, Pasi A. Janne, Jose M. Pacheco, Susanna Ulahannan, Judy S. Wang, Howard A. Burris, Jonathan W. Riess, Caroline McCoach, Michael S. Gordon, Anna Capasso, Ariel Chen, Richa Dua, Bojena Bitman, Martha Guerra, Hongfang Wang, Xiaolin Wang, Eric Haura. Confirmation of target inhibition and anti-tumor activity of the SHP2 inhibitor RMC-4630 via longitudinal analysis of ctDNA in a phase 1 clinical study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr LB054.

Abstract PS12-04: Rintodestrant (G1T48), an oral selective estrogen receptor degrader in ER+/HER2- locally advanced or metastatic breast cancer: Updated phase 1 results and dose selection

Background: Rintodestrant (G1T48) is a potent oral selective estrogen receptor degrader (SERD) that competitively binds to the estrogen receptor (ER) and blocks ER signaling in tumors resistant to other endocrine therapies. Preliminary results from Part 1 dose escalation showed robust target engagement on 18F-fluoroestradiol positron emission tomography (FES-PET), a favorable safety profile, and encouraging antitumor activity in patients with heavily pretreated ER+/HER2- advanced breast cancer (ABC), including those with ESR1 mutations (Dees et al., ESMO 2019 [abstract #3587]). Here, we present updated results from dose escalation and expansion (Parts 1 and 2). Methods: This Phase 1, first-in-human, open-label study evaluated rintodestrant monotherapy in women with ER+/HER2- ABC after progression on endocrine therapy. Part 1 was a 3+3 dose escalation (200-1000 mg once daily [QD]); Part 2 expanded 600 and 1000 mg QD; and Part 3 was added to assess rintodestrant with palbociclib in patients in earlier lines in the advanced setting. Primary objectives included dose-limiting toxicities (DLTs), maximum tolerated dose (MTD), safety, and recommended Phase 2 dose. Secondary objectives included pharmacokinetics and antitumor activity (RECIST v1.1). Exploratory objectives included pharmacodynamic inhibition of ER target engagement (FES-PET), mutation profiling (cell-free DNA [cfDNA]), and change in ER expression from baseline to on-treatment tumor biopsies. Results: As of May 13, 2020, 67 patients (Part 1: n = 26; Part 2: n = 41) were treated, with a median age of 61 years (range 34-83) and ECOG PS of 0 (49%) or 1 (51%). Median number of prior lines in the advanced setting was 2 (range 0-9), including prior fulvestrant (64%), CDK4/6 inhibitor (69%), mTOR inhibitor (22%), and/or chemotherapy (46%). Median number of prior lines of endocrine therapy in the advanced setting was 2 (range 0-5), with 61% of patients having received ≥2 lines. Treatment-related adverse events (TRAEs) were reported in 70% of patients. The most common TRAEs in ≥10% of patients included hot flush (24%), fatigue (21%), nausea (19%), diarrhea (18%), and vomiting (10%), mostly grade 1 or 2. No DLTs were reported and MTD was not reached. Dose reduction due to TRAEs occurred in 1 patient (1%), with elevated transaminases (grade 3 ALT and grade 2 AST) at 600 mg. Serious TRAEs occurred in 2 patients at 1000 mg (grade 5 cerebral hemorrhage in the setting of low molecular weight heparin and grade 2 upper abdominal pain). Two patients (3%) discontinued treatment due to TRAEs. Overall, the frequency of patients with TRAEs at 800 mg was comparable with that at 600 mg (57% vs 63%) and less than that at 1000 mg (81%). Of 67 patients, 16 were on study treatment for ≥24 weeks and 3 (n = 1 at 600 mg; n = 2 at 1000 mg, including 1 with ESR1 mutation) had a confirmed partial response (clinical benefit rate [CBR]: 28%). FES-PET standard uptake values decreased at week 4 with a mean reduction of 87% (±8%) at doses ≥ 600 mg. Of 59 patients tested for baseline cfDNA, 41% harbored ≥1 ESR1 mutation, with a similar CBR in both groups (33% in ESR1 mutant and 29% in ESR1 wild-type). Seven of 9 patients had a decrease in ER immunohistochemistry H-score at both 600 and 1000 mg (median [range]: -27.8% [-33.8%, -3.4%]), irrespective of ESR1 mutation status. Based on safety, efficacy, and ER degradation, 800 mg was selected as the optimal dose for further study. Conclusions: Rintodestrant continues to demonstrate an excellent safety/tolerability profile across all doses, with promising antitumor activity in patients with heavily pretreated ER+/HER2- ABC, including those with tumors harboring ESR1 mutations. Part 3 of this study, evaluating rintodestrant 800 mg QD with palbociclib in a more endocrine-sensitive population, is ongoing (NCT03455270).

Citation Format: Philippe Aftimos, Patrick Neven, Mark Pegram, Catharina Willemien Menke-van der Houven van Oordt, E. Claire Dees, Carolien Schröder, Agnes Jager, Iurie Bulat, Linnea Chap, Marina Maglakelidze, Erika Hamilton, Massimo Cristofanilli, Susanna Ulahannan, Jorianne Boers, Ramsha Iqbal, Adrian Crijanovschi, Curt D Wolfgang, Wenli Tao, Christina Sipes, Rajesh Malik, Sarika Jain. Rintodestrant (G1T48), an oral selective estrogen receptor degrader in ER+/HER2- locally advanced or metastatic breast cancer: Updated phase 1 results and dose selection [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 PS12-04.

Abstract PD8-07: Pharmacodynamic analysis from a phase 1 study of rintodestrant (G1T48), an oral selective estrogen receptor degrader, in ER+/HER2- locally advanced or metastatic breast cancer

Background: Rintodestrant is an orally bioavailable, potent and selective estrogen receptor degrader (SERD) that inhibits estrogen receptor (ER) gene transcription, degrades the ER, and delays tumor proliferation in preclinical models. Preliminary results from Part 1 dose escalation (200-1000 mg once daily) demonstrated that rintodestrant has a favorable safety profile and encouraging antitumor activity in patients (pts) with heavily pretreated ER+/HER2- advanced breast cancer (ABC) (Dees et al., ESMO 2019 [abstract #3587]). Here, we report the pharmacodynamic (PD) analysis in peripheral blood and tumor biopsies from pts who received rintodestrant in Part 1 and 2 (600 and 1000 mg dose expansion) to characterize the pt population and mechanisms of response. Methods: This Phase 1, first-in-human, open-label study evaluated rintodestrant in women with ER+/HER- ABC after progression on endocrine therapy. PD analysis included inhibition of ER target engagement with 18F-fluoroestradiol positron emission tomography (FES-PET), mutational profiling (cell-free DNA [cfDNA]), and circulating tumor cell (CTC) enumeration. Tumor biopsies sampled at baseline and 6 weeks on treatment were evaluated for ER degradation (immunohistochemistry [IHC]) and proliferation (Ki67, IHC) to understand the on-target effects of rintodestrant. Results: As of May 13, 2020, 67 pts had been treated. FES-PET data were obtained in 14 pts and showed a decrease in all pts, with maximum standard uptake values (SUVmax) ranging from 70% to 98% after 4 weeks of rintodestrant monotherapy across all doses. Fifty-nine pts were tested for cfDNA at baseline; 95% (n = 56) harbored ≥1 somatic variant (median = 3 mutations per pt). Among pts with somatic variants, 41% had ESR1 mutations, with D538G being the most common (58%). Additionally, 46% and 42% of pts harbored mutations in TP53 and PIK3CA, respectively, and 10% had mutations in both ESR1 and PIK3CA. Similar clinical benefit rates were observed in wild-type vs ESR1 and/or PIK3CA mutant tumors. An analysis of change of variant allele fraction (VAF) in 55 pts between baseline and 2 weeks of treatment revealed that 58% had a decrease in mean VAF, with a decrease in ESR1 VAF in 16/20 pts that had ESR1 mutations at baseline. Furthermore, of 24 pts who had samples collected at baseline and progression, 16 (67%) developed additional variants (median [range]: 2 [1, 15]), including EGFR, ERBB2, TP53, and ESR1. CTC analysis (n = 45) showed the mean value of Epi+CD45- CTCs decreased from 2.8 cells/mL to 1.8 cells/mL after 8 weeks of treatment. Tumor biopsies were collected in 9 pts (5 received 600 mg and 4 received 1000 mg) at baseline and 6 weeks on treatment. Of the 7/9 pts that had a decrease in the ER H-score (median [range]: -27.8% [-33.8%, -3.4%]), 4 had ≥1 variant in ESR1 at baseline. Overall, 4 pts had a decrease in Ki67, with reductions mostly observed in pts who received 600 mg rintodestrant. Additional analyses, including correlations with clinical response, are ongoing and will be presented. Conclusions: Rintodestrant demonstrated robust ER target engagement on FES-PET, as well as substantial decreases in ER H-score, cfDNA VAF, and Epi+CD45- CTCs. These data, along with promising clinical benefit in pts with heavily pretreated ER+/HER2- ABC, regardless of ESR1 or PIK3CA mutation status, warrant additional investigation of rintodestrant (NCT03455270).

Citation Format: Philippe Aftimos, Marina Maglakelidze, Andor WJM Glaudemans, Erika Hamilton, Linnea Chap, Elisabeth de Vries, Catharina Willemien Menke-van der Houven van Oordt, Agnes Jager, E. Claire Dees, Massimo Cristofanilli, Mark Pegram, Susanna Ulahannan, Patrick Neven, Iurie Bulat, Ruhi Rai, Wenli Tao, Sarika Jain, Andrew P Beelen, Jessica A Sorrentino. Pharmacodynamic analysis from a phase 1 study of rintodestrant (G1T48), an oral selective estrogen receptor degrader, in ER+/HER2- locally advanced or metastatic breast cancer [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 PD8-07.

Abstract B005: A phase I study of A166, a novel anti-HER2 antibody-drug conjugate (ADC), in patients with locally advanced/metastatic solid tumors

A Phase I study of A166, a Novel Anti-HER2 Antibody-Drug Conjugate (ADC), in Patients with Locally Advanced/Metastatic Solid Tumors. Purpose: A166 is an Antibody Drug Conjugate (ADC) targeting HER2-expressing cancer cells, aiming for post trastuzumab/TDM1 population and patients with HER2 expressing cancers not commonly treated with trastuzumab and TDM1. The antibody has the same amino acid sequence as trastuzumab, and it is designed to provide uniform distribution of payload molecules, using an innovative antibody-drug linker and duostatin-5 (an MMAF derivative) as payload. This ongoing phase I, open-label, first-in-human study is evaluating the safety, pharmacokinetics (PK), and dose-limiting toxicities (DLT) of A166 to determine the Maximum-Tolerated Dose (MTD) and/or recommended phase II dose (RP2D). Methods: Patients with advance solid tumors received escalating doses of A166 (0.3, 1.2, 3.6, and 4.8 mg/kg), administered intravenously (IV) every three weeks. Patients must have had documented HER2 positivity defined as positive, or amplified on in situ hybridization (ISH) or next-generation sequencing (NGS), or HER2 expression, defined as at least 1+ by validated immunohistochemistry (IHC) test or an activating HER2 mutation. Dose escalations were guided by a Bayesian logistic regression model (BLRM). Assessments include archival tumor molecular status, PK, and efficacy by Response Evaluation Criteria in Solid Tumors (RECIST). Results: 23 subjects [median age 68 (range 50-83), 17 female, 6 male, PS 0-1], have been treated. All patients had metastatic disease: 7 breast, 7 GC/GEJ/EC; 4 CRC, 5 other (lacrimal gland, vulvar, bladder, NSCLC, and ovarian). HER2 expression was available for all 23 patients: 12 (3+), 2 (2+ and amplified), 7 (amplified), 1 (1+), and 1 (HER2 mutated), and most had received previous HER2 targeted therapies (1-7 lines). No significant &gt; Grade 3 AEs at doses below 3.6 mg/kg have been observed. Based on safety and efficacy outcomes, dose levels (DLs) 3.6 and 4.8 mg/kg were expanded to a total of 7 and 8 patients respectively. In these two cohorts, 4 patients experienced grade 2 ophthalmic toxicities involving the ocular surface (3 keratitis, 1 blurred vision), and 2 had Grade 3 keratitis. Treatment was discontinued (n=3) or delayed (n=3), and patients were treated with topical steroids and aggressive lubrication. All patients have resolved/resolving status of the ophthalmic toxicities, with a duration from onset to recovery/improvement of symptoms of 2-3 weeks. Other common drug-related and reversible Grade 1-2 AEs include blurry vision (n=4), peripheral neuropathy (n=3), anemia (n=2), leukopenia (n=2), thrombocytopenia (n=2). No cardiac or liver toxicities have been noted. Preliminary response assessment found that efficacy is evident at DL 3.6 and 4.8 mg/kg. Of 8 evaluable patients at 3.6-4.8 DL, 4/8 had PR, and 6/8 had DCR. Among PRs, 3 had prior anti-HER2 therapies, including 2/3 with prior TDM1. Conclusion: A166 has been well tolerated and shows promising anti-tumor activity in patients with heavily pre-treated HER2-positive cancers. The ophthalmic AEs have been reversible and manageable with supportive management. A detailed regimen for early diagnosis and intervention has been developed to further investigate the management of these toxicities in future cohorts, and three additional dose levels (6.0, 7.2, 8.4 mg/kg) will be added to the escalation phase.

Citation Format: Diana M Lopez, Minal Barve, Judy Wang, Andrea J. Bullock, Eirini Pectasides, Ulka Vaishampayan, Alexander I. Spira, Susanna Ulahannan, Amita Patnaik, Rachel E. Sanborn, Dragan Cicic, Qiuqing Ang, Gregory Bergonio, Jordi Rodon Ahnert. A phase I study of A166, a novel anti-HER2 antibody-drug conjugate (ADC), in patients with locally advanced/metastatic solid tumors [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr B005. doi:10.1158/1535-7163.TARG-19-B005

Abstract 5015: Pretreatment carcinoembryonic antigen levels predict survival in patients with rectal adenocarcinoma

Background: Population-based studies have reported elevated Carcinoembryonic Antigen (CEA) level as an independent prognostic factor in patients with colon cancer, thus supporting inclusion of CEA-based C stage in classical TNM staging for colon cancer. However, the effect of C-stage incorporation on outcomes for patients with rectal adenocarcinoma is unknown.

Methods: The Surveillance, Epidemiology and End Result (SEER) database was used to collect data from 2004 to 2007 for patients with rectal adenocarcinoma by topography code C20.9 and histology codes 8140-8144, 8210-8211, 8220-8221, 8260-8263, 8440, 8480-8481, and 8490. CEA stage C0 = normal CEA or C1 = elevated CEA was assigned to patients with known pretreatment CEA levels. Observed survival (OS) by American Joint Committee on Cancer (AJCC) stages I-IV and CEA stage C0 or 1 was determined using Kaplan Meier method. Relative survival (RS) as a net measure of cancer survival adjusted for sex, race, age and date was calculated in addition to observed survival (OS). Log-rank was used to compare observed survival. Z-test with corresponding p values was used to compare 5-year relative survival.

Results: We identified 25,241 patients with a record of histologically confirmed invasive rectal adenocarcinoma. Approximately half (N = 13,151) of these patients had records of pretreatment CEA levels: N = 6,360 stage C1, N = 6,690 stage C0 and a small number (101) with borderline CEA levels. Mean age at diagnosis was similar in both groups, 64.2 for C0 and 64.7 for C1. Among patients with C1 disease the leading AJCC stage was distant metastatic, stage IV (33.8%) followed by 25.8% stage III, 20.7% stage II, 13.8% stage I, and 5.9% unknown stage. In contrast to CI disease, the most common stage for C0 was stage I (35.2%), and only 6.3% of patients with C0 were diagnosed with stage IV disease. Observed survival by each of I-IV AJCC TNM stages was decreased for C1 stage relative to C0, p&lt;0.001. The 5-year OS by AJCC TNM stage for C1 was as follows: 56.7% for IC1 (CI = 53.3-59.9), 55.4% for IIC1 (CI = 52.7-58.1), and 53.4% for IIIC1 (CI = 51.0-55.8). The 5-year OS by AJCC TNM stage for C0 was 75.8% for IC0 (CI = 74.1-77.5), 68.8% for IIC0 (CI = 66.5-71.0), 65.4% for IIIC0 (63.3-67.5). Stage shifting was observed with IIIC0 disease, which had superior OS as compared to stage IIC1 and IC1 (p&lt;0.001). For stage IV disease, the 5-year OS for C0 was more than double the 5 year OS for C1, 20.8 (17.1-24.9) vs. 7.9 (6.8-9.1), p&lt;0.001. In concordance with this OS data, the 5-year relative survival analysis also showed a significant difference between C1 and C0 stages of rectal adenocarcinoma in the respective AJCC TNM stages, p&lt;0.001.

Conclusion: Our study suggests that pretreatment CEA levels predict survival in patients with rectal adenocarcinoma, in accordance with previous data in colon cancer. Therefore, our study supports C-stage inclusion in AJCC TNM staging for this neoplasm. Further prospective confirmatory studies are warranted.

Citation Format: Oxana V. Makarova-Rusher, Julius Strauss, Susanna Ulahannan, Chul Kim, Jaydira Del Rivero, Austin Duffy, Tim F. Greten. Pretreatment carcinoembryonic antigen levels predict survival in patients with rectal adenocarcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 5015.

Abstract 3421: Epidemiology and survival in patients with extragastric signet ring carcinoma

Background: Signet ring carcinoma (SRC) is a distinct histological phenotype of adenocarcinoma. There are only a few published studies specifying the epidemiology of SRC with extragastric presentation. The purpose of our study was to define the most common primary sites of extragastric SRC, determine the incidence, and to compare survival by primary site and disease stage.

Methods: The Surveillance Epidemiology and End Result (SEER) database was examined from 2000 to 2012 in order to identify SRC histology (8490) and determine its most common primary sites, incidence, and survival by site and stage. The five most common primary extragastric sites were identified by utilizing ICD-0-3/WHO 2008 classification. Age-adjusted incidence rates for extragastric SRC were calculated and compared to gastric SRC. Relative survival (RS) and overall survival (OS) at 1 and 3 years were analyzed by primary site and stage using Kaplan-Meier method. Chi-square test was used for categorical variables.

Results: A total of 24,522 histologically confirmed cases of SRC were identified, and SRC comprised 0.5% of all malignant neoplasms. Among cases with known histological grade, 89.7% had poorly differentiated tumors. Overall, digestive system origin was recorded for 90% of SRC cases. Approximately half (44.2%) of primary SRC tumors were detected outside of the stomach. The most common primary sites for extragastric SRC were colon (40.5%), esophagus (11.9%), rectum (9.8%), lung/bronchus (7.3%), and pancreas (4.7%). The incidence rates for common extragastric SRC were much lower than for gastric SRC, and were higher for males than females (p&lt;0.001). Incidence profile differed by gender as breast was among top five SRC anatomical sites for females. Clinically, distant metastatic disease was more often diagnosed in patients with pancreatic (66.3%) and lung/bronchus (73.8%) SRC than SRC of the stomach (43.5%) (p&lt;0.01). Survival varied substantially by primary site. Pancreatic SRC had the worst survival and colorectal the most favorable. For example, among patients with stage IV disease, 1-year RS was 43.9% (95% CI = 41.1-46.6) for colorectal, 25.5% (95% CI = 20.6-30.6) for lung/bronchus, 20.9% (95% CI = 16.2-26.1) for esophageal, and only 10.7% (95% CI = 6.5-15.9) for pancreatic primary SRC. In concordance with 1-year RS, 3-year RS was 9.9% (95% CI = 8.2-11.9) for colorectal vs. 0.0% for pancreatic SRC.

Conclusion: Our study indicated that extragastric SRC most commonly occurs in the colorectum, esophagus and lung/bronchus. We confirmed that the primary site substantially impacts survival. Thus, development of unique molecular or histologic markers may help to identify the organ of origin and thereby determine prognosis in these phenotypically similar neoplasms.

Citation Format: Chul Kim, Susanna Ulahannan, Julius Strauss, Jaydira Del Rivero, Austin Duffy, Tim F. Greten, Oxana V. Makarova-Rusher. Epidemiology and survival in patients with extragastric signet ring carcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3421.

Population attributable fractions of risk factors for hepatocellular carcinoma in the United States

BACKGROUND

Hepatocellular carcinoma (HCC) incidence has been increasing in the United States for several decades; and, as the incidence of hepatitis C virus (HCV) infection declines and the prevalence of metabolic disorders rises, the proportion of HCC attributable to various risk factors may be changing.

METHODS

Data from the Surveillance, Epidemiology, and End Results-Medicare linkage were used to calculate population attributable fractions (PAFs) for each risk factor over time. Patients with HCC (n = 10,708) who were diagnosed during the years 2000 through 2011 were compared with a 5% random sample of cancer-free controls (n = 332,107) residing in the Surveillance, Epidemiology, and End Results areas. Adjusted odds ratios (ORs) and PAFs were calculated for HCV, hepatitis B virus (HBV), metabolic disorders, alcohol-related disorders, smoking, and genetic disorders.

RESULTS

Overall, the PAF was greatest for metabolic disorders (32%), followed by HCV (20.5%), alcohol (13.4%), smoking (9%), HBV (4.3%), and genetic disorders (1.5%). The PAF for all factors combined was 59.5%. PAFs differed by race/ethnicity and sex. Metabolic disorders had the largest PAF among Hispanics (PAF, 39.3%; 95% confidence interval [CI], 31.9%-46.7%) and whites (PAF, 34.8%; 95% CI, 33.1%-36.5%), whereas HCV had the largest PAF among blacks (PAF, 36.1%; 95% CI, 31.8%-40.4%) and Asians (PAF, 29.7%; 95% CI, 25.9%-33.4%). Between 2000 and 2011, the PAF of metabolic disorders increased from 25.8% (95% CI, 22.8%-28.9%) to 36% (95% CI, 33.6%-38.5%). In contrast, the PAFs of alcohol-related disorders and HCV remained stable.

CONCLUSIONS

Among US Medicare recipients, metabolic disorders contribute more to the burden of HCC than any other risk factor, and the fraction of HCC caused by metabolic disorders has increased in the last decade. Cancer 2016;122:1757-65. Published 2016. This article is a U.S. Government work and is in the public domain in the USA..