Exposure-response (E-R) efficacy and safety (E-S) analyses of tremelimumab as monotherapy or in combination with durvalumab in patients (pts) with unresectable hepatocellular carcinoma (uHCC)

313

Background: In a phase II study in uHCC (Study 22, NCT02519348), a novel, priming combination regimen of tremelimumab (T; anti-CTLA-4) and durvalumab (D; anti-PD-L1) (T300+D) has shown favorable clinical activity vs each agent as monotherapy or vs another combination (T75+D). The analyses presented here assess the pharmacokinetics (PK) and relationships between tremelimumab exposure, as monotherapy or in combination, and safety, efficacy, and pharmacodynamics (PD) in this study. Methods: Overall, 216 pts were included in these analyses (T, n=65; T300+D, n=72; T75+D, n=79). Safety, antitumor activity, PK, PD, and immunogenicity were analyzed using standard pharmacometrics methods. A previously developed population PK model for T across solid tumors was validated using T monotherapy and combination therapy data from Study 22, including a post-hoc covariate analysis to assess the impact of covariates on individual PK parameters. Population PK and PD models related individual T exposures to safety parameters, PD, and efficacy (overall survival, OS; progression-free survival, PFS; and objective response rate, ORR). The E-R relationships for time-to-event variables OS and PFS were explored by Kaplan-Meier estimates and analyzed by Cox proportional-hazards models (CPHM). Results: For T monotherapy and T+D combinations, no significant E-S relationships were observed for grade 3/4 treatment-related adverse events (TRAEs), grade 3/4 TRAEs of special interest, and AEs leading to treatment discontinuation. Analyses of each quartile of T exposure suggest pts with higher exposure (3rd and 4th quartile) may have longer OS vs lower quartiles. The CPHManalysis showed that after accounting for prognostic factors (baseline albumin and neutrophil-to-lymphocyte ratio), neither AUC nor Cmin appeared to be a significant factor for OS hazard. There was no significant relationship between response and ORR, PFS and any T PK exposure metric in T-treated pts. Saturable relationships (described by Emax) were observed for maximum change from baseline for proliferating T-cell counts as functions of exposure. Conclusions: The observed PK data are generally consistent with predictions based on a historical population PK model, suggesting the PK of T in uHCC pts is consistent with pts with other solid tumors. No significant relationships were observed between E-S and E-R; therefore, PK is not a significant predictor to evaluate for T efficacy or safety. Considering the small sample size limitation, still the saturable relationships observed in proliferating T-cells appear to support a dose of T300. Future studies of pooled data from Study 22 and the larger phase III HIMALAYA study (NCT03298451) will be conducted to further the characterization of E-R relationships and the development of the T300+D regimen. Clinical trial information: NCT02519348.

Longitudinal evaluation of quality of life (QoL) in patients (Pts) with FGFR2-driven cholangiocarcinoma (CCA) treated with pemigatinib

276

Background: CCA is associated with poor prognosis and reduced QoL. In the phase 2 FIGHT-202 study (NCT02924376) of the selective oral FGFR1–3 inhibitor pemigatinib, 35.5% and 46.7% of pts with previously treated advanced CCA and FGFR2 fusions/rearrangements (RE) had a complete or partial response (CR/PR) and stable disease (SD), respectively; 14.9% had progressive disease (PD) [Abou-Alfa et al., Lancet Oncology 2020;21:671-684]. QoL was an exploratory endpoint. Methods: Pts received pemigatinib 13.5 mg once daily (21-day cycle; 2 weeks on, 1 week off). QoL was assessed longitudinally by best overall response (BOR) per RECIST with the EORTC-QLQ-C30 and the biliary tract cancer-specific EORTC-QLQ-BIL21 questionnaires. QoL scores and longitudinal changes from baseline (BL) were analyzed using descriptive statistics. Treatment-related changes in QoL were a priori expected to be evident by cycle 6 day 1 (week 16). Results: Of 107 pts with FGFR2 RE, 100 (93%) were evaluable for QoL, including36, 48, and 15 with CR/PR, SD, and PD, respectively. From BL to week 16, QLQ-C30 overall health status was maintained in pts with CR/PR and SD and worsened in pts with PD (Table). Emotional functioning remained stable and similar in pts with CR/PR and SD but worsened in pts with PD. All subgroups showed decline in role and social functioning. Pts with CR/PR and SD experienced decreases in QLQ-BIL21 pain and anxiety; all subgroups showed increases in QLQ-BIL21 treatment side effects. Conclusions: In these pts with advanced CCA, those with an SD as BOR had a similar pattern of changes in QoL as those with CR/PR to pemigatinib. Changes in QoL were directionally more favorable in pts with CR/PR or SD than pts with PD. Clinical trial information: NCT02924376. [Table: see text]

Association between post-treatment (tx) alpha-fetoprotein (AFP) reduction and outcomes in real-world (rw) U.S. patients (pts) with advanced HCC (aHCC)

341

Background: A decrease in post-tx AFP may be associated with improved outcomes in clinical trials. However, the impact of AFP reduction after initiation of a first-line (1L) tyrosine kinase inhibitor (TKI) therapy on outcomes is unclear among pts with aHCC treated in routine clinical practice. Methods: This analysis utilized data from the nationwide Flatiron Health electronic health record (EHR)-derived de-identified database and included pts with aHCC with ≥2 visits between 1/1/2011-7/31/2019 who received 1L TKI. Pts with a baseline serum AFP value (closest to 1L initiation within -30 to +7 days) and a post-tx AFP value (closest to 8 weeks after 1L initiation within ±2 weeks) were included. Post-tx AFP reduction was defined as a ≥20% decrease from baseline AFP, and no reduction as a <20% decrease or any increase. Rw overall survival (rwOS) was defined as time from post-tx AFP measurement to death (censored at last EHR activity). Rw progression-free survival (rwPFS) was based on clinician documentation and defined as the first progression event or death after post-tx AFP measurement (censored at last clinic note date). Adjusted hazard ratios (aHR) for reduction vs no reduction (reference) were estimated using multivariable Cox proportional hazards models adjusted for potential confounders and baseline AFP. Effect modification was assessed by conducting tests for interactions with analyses stratified by HCC risk factors. Results: 441 pts were included in the study. 8% had documented history (hx) of hepatitis B (HBV), 52% hepatitis C (HCV), 47% obesity/diabetes (DM), 42% heavy alcohol use, and 11% no documented risk factor. Median baseline AFP was 210 ng/mL (IQR 237 - 2981) and 150 ng/mL (IQR 17 - 1311) among pts with reduction (N = 150) and no reduction (N = 291). There was a 35% decrease in hazard of death for pts with reduction vs no reduction (median rwOS 10.3 vs 6.7 months; Table). Similarly, a 35% decrease in hazard of rw progression or death was observed for pts with reduction vs no reduction (aHR=0.65; 95% CI: 0.52-0.81; median rwPFS 4.4 vs 2.4 months). Reduction (vs no) was associated with better rwOS among pts with hx of HCV, obesity/DM or alcohol use vs without the respective risk factor, however, no statistically significant interactions were observed (Table). Conclusions: Results show post-tx AFP reduction may be prognostic for rwPFS and rwOS in pts with aHCC treated with 1L TKI. Further research may clarify if prognostic value differs by HCC risk factor profile. [Table: see text]

Targeting HER2 (ERBB2) mutation-positive advanced biliary tract cancers with neratinib: Results from the phase II SUMMIT ‘basket’ trial

320

Background: Genomic profiling studies have reported somatic HER2 mutations in ~2–5% of biliary tract cancers (BTC). Clinical data from the SUMMIT study demonstrate that neratinib, a pan-HER irreversible tyrosine kinase inhibitor, has encouraging clinical activity in multiple types of HER2-mutant solid tumor malignancies. Methods: SUMMIT is a multi-histology, open-label, phase II ‘basket’ study of neratinib in patients with somatic HER2 mutations (ClinicalTrials.gov NCT01953926). Patients with activating somatic HER2 mutations with different histologies, including BTC, received neratinib monotherapy (240 mg oral daily). Loperamide prophylaxis was mandatory during cycle 1. Efficacy endpoints: objective response rate (ORR, RECIST v1.1); clinical benefit rate (CBR); duration of response; progression-free survival (PFS). Adverse events (AEs) were assessed by CTCAE v4.0. Genomic profiling from fresh/archival tumor tissues and/or plasma cfDNA was performed retrospectively by next-generation sequencing (MSK-IMPACT). Results: As of 3-Sep-2020, 25 patients with HER2-mutant BTC were enrolled: gallbladder (40%); intrahepatic (24%); extrahepatic (20%); ampulla of Vater (16%). 68% of patients received ≥2 systemic regimens (96% received prior gemcitabine-based regimens). The S310F/Y variant accounted for nearly half of HER2 mutations (n=11). Other HER2 mutations: V777L (n=5); L755S (n=2); V842I (n=2); R678Q (n=2). Confirmed ORR in 25 evaluable patients was 12% (95% CI 3–31%) and CBR was 20% (95% CI 7–41%), including 3 confirmed PRs and 2 patients with SD for ≥16 weeks. Tumor shrinkage was observed in multiple HER2-activating mutations and enriched in gallbladder and extrahepatic subtypes of BTC. Median PFS was 2.8 (95% CI 1.1–3.7) months; median overall survival (OS) was 5.4 (95% CI 3.7–11.7) months. Nine (36%) patients (3 of whom with ECOG PS 2) came off study within 28 (range 6–47) days of treatment due to clinical deterioration (unrelated to study drug) followed by death. The most common treatment-related AEs (any grade) were diarrhea (56%) and vomiting (48%). Diarrhea was the most common Grade 3 event (24%); 4 patients (16%) required a neratinib dose reduction; no patients discontinued treatment due to diarrhea. Conclusions: Neratinib is safe and tolerable in patients with advanced BTC patients and somatic HER2 mutations. The antitumor activity of neratinib appears comparable to current standards of care, with similar PFS and OS in heavily pretreated patients. Analysis of co-occurring oncogenic mutations and response is ongoing, and consideration is being given to neratinib-based combination regimens to further improve outcomes in this setting. Clinical trial information: NCT01953926.

Evaluation of neratinib (N), pembrolizumab (P), everolimus (E), and nivolumab (V) in patients (pts) with fibrolamellar carcinoma (FLC)

310

Background: FLC, a rare liver cancer of young adults, has no effective systemic therapies. Surgical resection is used extensively with non-curative intent. FLC is associated with a DNAJB1- PRKACA chimeric transcript that produces a fusion protein with retained kinase activity and increased expression of several oncogenic signaling pathways including, but not limited to, HER2 ( ERBB2). Methods: N (240 mg oral daily) was studied in FLC pts in the SUMMIT study (NCT01953926); and later under compassionate use for N-based combinations (combo): P (2 mg/kg q3w), E (7.5 mg daily), and V (240 mg q2w) in doublet or triplet regimens. Eligible pts: ≥12y; histologically confirmed FLC; adequate organ function; any number of prior therapies. Primary endpoint: objective response rate (ORR; RECIST v1.1). Secondary endpoints: duration of response; clinical benefit rate (CBR); safety (CTCAE v4.0); somatic and germline sequencing (MSK IMPACT). Results: As of 03-Sep-2020, 15 pretreated pts received N in SUMMIT (confirmed ORR 0%; CBR 13%). Efficacy data for 5 pts from SUMMIT and 2 more pts receiving combo under compassionate use (4 male, 3 female, median age 26 years, median 0 [range 0–4] prior systemic therapies) are in shown in the table. The most common adverse events (AE) with single-agent N (n = 5) were diarrhea (grade 1 80%; grade 2 20%) and nausea (grade 1 60%); other AEs were grade ≤1 in ≤20% of pts. Conclusions: N monotherapy had limited benefit as a single agent in FLC pts. Several case studies evaluating N-based combo with checkpoint inhibitors administered under compassionate use demonstrated that NP led to 1 PR, and the triplet of NPE to prolonged SD. These are case-limited observations but are critical and worth evaluating further in upcoming clinical trials given the continued lack of a standard of care therapy for pts with FLC. Clinical trial information: NCT01953926. [Table: see text]

Final results from ClarIDHy, a global, phase III, randomized, double-blind study of ivosidenib (IVO) versus placebo (PBO) in patients (pts) with previously treated cholangiocarcinoma (CCA) and an isocitrate dehydrogenase 1 (IDH1) mutation

266

Background: CCA is a rare cancer for which there are limited effective therapies. IDH1 mutations occur in ~20% of intrahepatic CCAs, resulting in production of the oncometabolite D-2-hydroxyglutarate, which promotes oncogenesis. IVO (AG-120) is a first-in-class, oral, small-molecule inhibitor of mutant IDH1 (m IDH1). ClarIDHy aimed to demonstrate the efficacy of IVO vs PBO in pts with unresectable or metastatic m IDH1 CCA. The primary endpoint was met with significant improvement in progression-free survival (PFS) by independent radiology center (IRC) with IVO vs PBO (hazard ratio [HR] = 0.37, p < 0.0001). Objective response rate (ORR) and stable disease for IVO were 2.4% (3 partial responses) and 50.8% (n = 63) vs 0% and 27.9% (n = 17) for PBO. IVO pts experienced significantly less decline in physical and emotional functioning domains of quality of life at cycle 2 day 1 vs PBO pts (nominal p < 0.05). Methods: Pts with m IDH1 CCA were randomized 2:1 to IVO (500 mg PO QD) or matched PBO and stratified by prior systemic therapies (1 or 2). Key eligibility: unresectable or metastatic m IDH1 CCA based on central testing; ECOG PS 0–1; measurable disease (RECIST v1.1). Crossover from PBO to IVO was permitted at radiographic progression. Primary endpoint: PFS by IRC. Secondary endpoints included overall survival (OS; by intent-to-treat), ORR, PFS (by investigator), safety, and quality of life. The planned crossover-adjusted OS was derived using the rank-preserving structural failure time (RPSFT) model. Results: As of 31 May 2020, ~780 pts were prescreened for an IDH1 mutation and 187 were randomized to IVO (n = 126) or PBO (n = 61); 13 remain on IVO. Median age 62 y; M/F 68/119; 91% intrahepatic CCA; 93% metastatic disease; 47% had 2 prior therapies. 70% of PBO pts crossed over to IVO. OS data were mature, with 79% OS events in IVO arm and 82% in PBO. Median OS (mOS) was 10.3 months for IVO and 7.5 months for PBO (HR = 0.79; 95% CI 0.56–1.12; one-sided p = 0.093). The RPSFT-adjusted mOS was 5.1 months for PBO (HR = 0.49; 95% CI 0.34–0.70; p < 0.0001). Common all-grade treatment emergent adverse events (TEAEs, ≥ 15%) in the IVO arm: nausea 41%, diarrhea 35%, fatigue 31%, cough 25%, abdominal pain 24%, decreased appetite 24%, ascites 23%, vomiting 23%, anemia 18%, and constipation 15%. Grade ≥ 3 TEAEs were reported in 50% of IVO pts vs 37% of PBO pts, with grade ≥ 3 treatment-related AEs in 7% of IVO pts vs 0% in PBO. 7% of IVO pts experienced an AE leading to treatment discontinuation vs 9% of PBO pts. There were no treatment-related deaths. Conclusions: IVO was well tolerated and resulted in a favorable OS trend vs PBO despite a high rate of crossover. These data – coupled with statistical improvement in PFS, supportive quality of life data, and favorable safety profile – demonstrate the clinical benefit of IVO in advanced m IDH1 CCA. Clinical trial information: NCT02989857.

A phase III, double-blind, randomized study of nivolumab (NIVO) and ipilimumab (IPI), nivo monotherapy or placebo plus transarterial chemoembolization (TACE) in patients with intermediate-stage hepatocellular carcinoma (HCC)

TPS349

Background: TACE is the most widely used locoregional therapy recommended for patients with intermediate-stage HCC (Barcelona Clinic Liver Cancer stage B). Despite the significant tumor responses that can be achieved with TACE, tumors commonly recur, progress, or are refractory. Clinical trials have explored the combination of TACE with tyrosine kinase inhibitors; however, these have not reported improved outcomes. HCC possesses a unique immunosuppressive microenvironment, which makes it an attractive target for immunotherapies, particularly immune checkpoint inhibitors. Furthermore, there is evidence that locoregional interventions induce changes in the immune environment that could promote synergy with checkpoint inhibitors. Preliminary data for the combination of TACE with nivolumab indicate an acceptable safety profile and promising efficacy (Harding et al. ASCO-GI 2020). NIVO monotherapy and NIVO+IPI combination therapy are both approved in the United States for patients with HCC previously treated with sorafenib. Together, these findings support investigation of TACE plus NIVO, IPI, or NIVO+IPI to address the therapeutic needs of patients with intermediate HCC. Methods: CheckMate 74W is a global, double-blind, placebo-controlled, 3-arm, randomized phase III trial. Patients with tumors that exceed the Beyond Milan and Up-to-7 criteria (7 being the sum of size [in centimeters] and number of tumors), eligible for TACE, with Eastern Cooperative Oncology Group performance status of 0 to 1 are eligible for enrollment. Patients must not have received prior locoregional therapies. Approximately 765 patients will be randomized in a 1:1:1 ratio to NIVO+IPI+TACE (arm A), NIVO+IPI placebo+TACE (arm B), or NIVO placebo+IPI placebo+TACE (arm C). Primary endpoints are the time to TACE progression (TTTP), assessed by blinded independent central review, and overall survival in arm A versus arm C. Secondary endpoints are TTTP and overall survival in arm B versus arm C, event-free survival, and progression-free survival. Clinical trial registry: NCT04340193. Clinical trial information: NCT04340193.

Final results from a phase II study of infigratinib (BGJ398), an FGFR-selective tyrosine kinase inhibitor, in patients with previously treated advanced cholangiocarcinoma harboring an FGFR2 gene fusion or rearrangement

265

Background: Treatment options for cholangiocarcinoma (CCA) after progression on first-line gemcitabine-based therapy are limited. Fibroblast growth factor receptor 2 ( FGFR2) gene fusions occur in 13–17% of intrahepatic CCA. A single-arm, phase II study (NCT02150967) evaluated infigratinib, an ATP-competitive FGFR1–3-selective oral tyrosine kinase inhibitor, in previously-treated advanced CCA with FGFR fusions/rearrangements. Methods: Adult patients with advanced/metastatic CCA with progression on ≥1 line of systemic therapy received infigratinib 125 mg orally for 21 days of each 28-day cycle until unacceptable toxicity or disease progression. All patients received prophylaxis with the oral phosphate binder sevelamer. Primary endpoint: objective response rate (ORR) by independent central review per RECIST v1.1, with duration of response (DOR). Secondary endpoints: progression-free survival (PFS), disease control rate, overall survival, safety, pharmacokinetics. Approximately 160 patients are planned (120/20/20 patients in Cohorts 1/2/3). This analysis focuses on Cohort 1 (patients with FGFR2 gene fusions or rearrangements without receiving a prior FGFR inhibitor). Results: As of 31 March 2020, 108 patients, including 83 (77%) with FGFR2 fusions, received infigratinib: median age 53 years (range 23–81 years); 54% had received ≥2 prior treatment lines. Median follow-up was 10.6 months (range 1.1–55.9 months). 96 patients (88.9%) discontinued treatment (12 ongoing). Centrally reviewed ORR was 23.1% (95% CI 15.6–32.2) including 1 CR and 24 PRs; median DOR was 5.0 months (range 0.9–19.1 months). Among responders, 8 (32.0%) patients had a DOR of ≥6 months. Median PFS was 7.3 months (95% CI 5.6–7.6 months). Prespecified subgroup analysis: ORR was 34% (17/50) in the second-line setting and 13.8% (8/58) in the third-/later-line setting (3–8 prior treatments). Most common treatment-emergent adverse events (TEAEs, any grade) were hyperphosphatemia (76.9%), eye disorders (67.6%, excluding central serous retinopathy/retinal pigment epithelium detachment [CSR/RPED]), stomatitis (54.6%), and fatigue (39.8%). CSR/RPED occurred in 16.7% of patients (including 1 G3 event; 0 G4). Other common grade 3/4 TEAEs were stomatitis (14.8%; all G3), hyponatremia (13.0%; all G3), and hypophosphatemia (13.0%; 13 G3, 1 G4). Conclusions: Infigratinib is associated with promising anticancer activity and a manageable AE profile in patients with advanced, refractory CCA with an FGFR2 gene fusion or rearrangement. A phase III study of infigratinib versus gemcitabine/cisplatin is ongoing in the front-line setting (NCT03773302). Clinical trial information: NCT02150967.

Noninvasive Detection of Polyclonal Acquired Resistance to FGFR Inhibition in Patients With Cholangiocarcinoma Harboring FGFR2 Alterations

PURPOSE

Fibroblast growth factor receptor (FGFR) 2 alterations, present in 5%-15% of intrahepatic cholangiocarcinomas (IHC), are targets of FGFR-directed therapies. Acquired resistance is common among patients who respond. Biopsies at the time of acquired resistance to targeted agents may not always be feasible and may not capture the genetic heterogeneity that could exist within a patient. We studied circulating tumor DNA (ctDNA) as a less invasive means of potentially identifying genomic mechanisms of resistance to FGFR-targeted therapies.

MATERIALS AND METHODS

Serial blood samples were collected from eight patients with FGFR-altered cholangiocarcinoma for ctDNA isolation and next-generation sequencing (NGS) throughout treatment and at resistance to anti-FGFR-targeted therapy. ctDNA was sequenced using a custom ultra-deep coverage NGS panel, incorporating dual index primers and unique molecular barcodes to enable high-sensitivity mutation detection.

RESULTS

Thirty-one acquired mutations in FGFR2, 30/31 located in the kinase domain, were identified at resistance in six of eight patients with detectable ctDNA. Up to 13 independent FGFR2 mutations were detected per patient, indicative of striking genomic concordance among resistant subclones.

CONCLUSION

ctDNA could be an effective means to longitudinally monitor for acquired resistance in FGFR2-altered IHC. The numerous acquired genetic alterations in FGFR2 suggest frequent polyclonal mechanisms of resistance that cannot be detected from single-site tissue biopsies.

Systemic Therapy for Advanced Hepatocellular Carcinoma: ASCO Guideline

PURPOSE

To develop an evidence-based clinical practice guideline to assist in clinical decision making for patients with advanced hepatocellular carcinoma (HCC).

METHODS

ASCO convened an Expert Panel to conduct a systematic review of published phase III randomized controlled trials (2007-2020) on systemic therapy for advanced HCC and provide recommended care options for this patient population.

RESULTS

Nine phase III randomized controlled trials met the inclusion criteria.

RECOMMENDATIONS

Atezolizumab + bevacizumab (atezo + bev) may be offered as first-line treatment of most patients with advanced HCC, Child-Pugh class A liver disease, Eastern Cooperative Oncology Group Performance Status (ECOG PS) 0-1, and following management of esophageal varices, when present, according to institutional guidelines. Where there are contraindications to atezolizumab and/or bevacizumab, tyrosine kinase inhibitors sorafenib or lenvatinib may be offered as first-line treatment of patients with advanced HCC, Child-Pugh class A liver disease, and ECOG PS 0-1. Following first-line treatment with atezo + bev, and until better data are available, second-line therapy with a tyrosine kinase inhibitor may be recommended for appropriate candidates. Following first-line therapy with sorafenib or lenvatinib, second-line therapy options for appropriate candidates include cabozantinib, regorafenib for patients who previously tolerated sorafenib, or ramucirumab (for patients with α-fetoprotein ≥ 400 ng/mL), or atezo + bev where patients did not have access to this option as first-line therapy. Pembrolizumab or nivolumab are also reasonable options for appropriate patients following sorafenib or lenvatinib. Consideration of nivolumab + ipilimumab as an option for second-line therapy and third-line therapy is discussed. Further guidance on choosing between therapy options is included within the guideline. Additional information is available at www.asco.org/gastrointestinal-cancer-guidelines.

Association of inflammatory biomarkers with clinical outcomes in nivolumab-treated patients with advanced hepatocellular carcinoma

BACKGROUND & AIMS

Nivolumab, a programmed death (PD)-1 (PD-1) inhibitor, led to durable responses, manageable safety, and increased survival in patients with advanced hepatocellular carcinoma (HCC). In our retrospective analysis, we studied the immunobiology and potential associations between biomarkers and outcomes with nivolumab in HCC.

METHODS

Fresh and archival tumour samples from dose-escalation and dose-expansion phases of the CheckMate 040 trial were analysed by immunohistochemistry and RNA sequencing to assess several inflammatory gene expression signatures, including CD274 (PD-ligand 1 [PD-L1]), CD8A, LAG3, and STAT1. Biomarkers were assessed for association with clinical outcomes (best overall response by blinded independent central review per RECIST v1.1 and overall survival [OS]).

RESULTS

Complete or partial tumour responses were observed in PD-L1-positive and PD-L1-negative patients treated with nivolumab monotherapy. Median OS was 28.1 (95% CI 18.2-n.a.) vs. 16.6 months (95% CI 14.2-20.2) for patients with tumour PD-L1 ≥1% vs. <1% (p = 0.03). Increased CD3 and CD8 showed a non-significant trend towards improved OS (both p = 0.08), and macrophage markers were not associated with OS. Tumour PD-1 and PD-L1 expression were associated with improved OS (p = 0.05 and p = 0.03, respectively). An inflammatory gene signature consisting of 4 genes was associated with improved objective response rate (p = 0.05) and OS (p = 0.01).

CONCLUSIONS

PD-1 and PD-L1 expression, biomarkers of inflammation, and inflammatory gene signatures trended with improved survival and response. While further confirmation within a larger phase III trial is needed to evaluate predictive value of these biomarkers, these exploratory analyses suggest that anti-tumour immune response may play a role in the treatment benefit of nivolumab in HCC.

LAY SUMMARY

Certain tests may be used to provide a picture of how a tumour is escaping the immune system, allowing it to continue to grow and create more tumours. Therapies such as nivolumab are designed to help the immune system fight the tumour. These tests may be used to determine how effective such therapies will be in the treatment of advanced liver cancer.

NCT NUMBER

NCT01658878.

FIGHT-302: first-line pemigatinib vs gemcitabine plus cisplatin for advanced cholangiocarcinoma with FGFR2 rearrangements

FGFR2 rearrangements resulting in dysregulated signaling are drivers of cholangiocarcinoma (CCA) tumorigenesis, and occur almost exclusively in intrahepatic CCA. Pemigatinib, a selective, potent, oral inhibitor of FGFR1-3, has demonstrated efficacy and safety in a Phase II study of patients with previously treated locally advanced/metastatic CCA harboring FGFR2 fusions/rearrangements. We describe the study design of FIGHT-302, an open-label, randomized, active-controlled, multicenter, global, Phase III study comparing the efficacy and safety of first-line pemigatinib versus gemcitabine plus cisplatin in patients with advanced CCA with FGFR2 rearrangements (NCT03656536). The primary end point is progression-free survival; secondary end points are objective response rate, overall survival, duration of response, disease control rate, safety and quality of life. Clinical Trial Registration: NCT03656536 (ClinicalTrials.gov).

Serum Alpha-fetoprotein Levels and Clinical Outcomes in the Phase III CELESTIAL Study of Cabozantinib versus Placebo in Patients with Advanced Hepatocellular Carcinoma

PURPOSE

The phase III CELESTIAL study demonstrated improved overall survival (OS) and progression-free survival (PFS) with cabozantinib versus placebo in patients with previously treated, advanced hepatocellular carcinoma (HCC). We analyzed outcomes by baseline alpha-fetoprotein (AFP) and on-treatment AFP changes.

PATIENTS AND METHODS

Serum AFP was measured every 8 weeks by blinded, centralized testing. Outcomes were analyzed by baseline AFP bifurcated at 400 ng/mL and by on-treatment AFP response (≥20% decrease from baseline at Week 8). The optimal cutoff for change in AFP at Week 8 was evaluated using maximally selected rank statistics.

RESULTS

Median OS for cabozantinib versus placebo was 13.9 versus 10.3 months [HR, 0.81; 95% confidence interval (CI), 0.62-1.04] for patients with baseline AFP <400 ng/mL, and 8.5 versus 5.2 months (HR, 0.71; 95% CI, 0.54-0.94) for patients with baseline AFP ≥400 ng/mL. Week 8 AFP response rate was 50% for cabozantinib versus 13% for placebo. In the cabozantinib arm, median OS for patients with and without AFP response was 16.1 versus 9.1 months (HR, 0.61; 95% CI, 0.45-0.84). AFP response was independently associated with longer OS. The optimal cutoff for association with OS in the cabozantinib arm was ≤0% change in AFP at Week 8 [AFP control; HR 0.50 (95% CI, 0.35-0.71)]. HRs for PFS were consistent with those for OS.

CONCLUSIONS

Cabozantinib improved outcomes versus placebo across a range of baseline AFP levels. On-treatment AFP response and control rates were higher with cabozantinib than placebo, and were associated with longer OS and PFS with cabozantinib.

NRF2 Dysregulation in Hepatocellular Carcinoma and Ischemia: A Cohort Study and Laboratory Investigation

Background Intermediate stage hepatocellular carcinomas (HCCs) are treated by inducing ischemic cell death with transarterial embolization (TAE) or transarterial chemoembolization (TACE). A subset of HCCs harbor nuclear factor E2-related factor 2 (NRF2), a major regulator of the oxidative stress response implicated in cell survival after ischemia. NRF2-mutated HCC response to TAE and/or TACE is unknown. Purpose To test whether ischemia resistance is present in individuals with NRF2-mutated HCC and if this resistance can be overcome by means of NRF2 inhibition in HCC cell lines. Materials and Methods This was a combined retrospective review of an institutional database (from January 2011 to December 2018) and prospective study (from January 2014 to December 2018) of participants with HCC who underwent TAE and a laboratory investigation of HCC cell lines. Imaging follow-up included liver CT or MRI at 1 month after the procedure followed by 3-month interval scans. Tumor radiologic response was assessed on the basis of follow-up imaging. The time to local progression after TAE for individuals with and individuals without NRF2 pathway alterations was estimated by using competing risk analysis (Gray test). The in vitro response to ischemia in four HCC cell lines with and without NRF2 overexpression was evaluated, and the combination of ischemia with NRF2 knockdown by means of short hairpin RNA or an NRF2 inhibitor was tested. Doubling time estimates, dose response curve regression, and comparison analyses were performed. Results Sixty-five individuals (median age, 69 years [range, 19-84 years]; 53 men) were evaluated. HCCs with NRF2 pathway mutation had a shorter time to local progression after TAE compared to those without mutation (6-month cumulative incidence of local progression, 56% [range, 19%-91%] vs 22% [range, 12%-34%], respectively; P < .001) and confirmed ischemia resistance in NRF2-overexpressing HCC cell lines. However, ischemia and NRF2 knock-down worked synergistically to decrease proliferation of NRF2-overexpressing HCC cell lines. Dose response curves of ML385, an NRF2 inhibitor, showed that ischemia induces addiction to NRF2 in cells with NRF2 alterations. Conclusion Hepatocellular carcinoma with nuclear factor E2-related factor 2 (NRF2) alterations showed resistance to ischemia, but ischemia simultaneously induced sensitivity to NRF2 inhibition. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Weiss and Nezami in this issue.

Molecular profiling and analysis of genetic aberrations aimed at identifying potential therapeutic targets in fibrolamellar carcinoma of the liver

BACKGROUND

Fibrolamellar carcinoma (FLC) is a rare primary liver cancer of young adults. A functional chimeric transcript resulting from the in-frame fusion of the DNAJ homolog, subfamily B, member 1 (DNAJB1), and the catalytic subunit of protein kinase A (PRKACA) genes on chromosome 19 is believed to be unique in FLC, with a possible role in pathogenesis, yet with no established therapeutic value. The objective of the current study was to understand the molecular landscape of FLC and to identify potential novel therapeutic targets.

METHODS

Archival fresh, formalin-fixed, paraffin-embedded samples from patients with FLC who prospectively consented to an institutional review board-approved protocol were analyzed using Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets (MSK-IMPACT), a next-generation sequencing assay encompassing up to 468 key cancer genes. Custom targeted RNA-Seq was performed in selected patients. Demographics, treatment, and outcome data were collected prospectively. Survival outcomes were estimated and correlated with mutation and/or copy number alterations.

RESULTS

A total of 33 tumor samples from 31 patients with FLC were analyzed. The median age of the patients at the time of diagnosis was 18 years and approximately 53% were women. The DNAJB1-PRKACA fusion transcript was detected in 100% of patients. In 10 of 31 patients in which MSK-IMPACT did not detect the fusion, its presence was confirmed by targeted RNA-Seq. TERT promoter mutation was the second most common, and was detected in 7 patients. The median follow up was 30 months (range, 6-153 months). The 3-year overall survival rate was 84% (95% CI, 61%-93%).

CONCLUSIONS

The DNAJB1-PRKACA fusion transcript is nonspecific and nonsensitive to FLC. Its potential therapeutic value currently is under evaluation. Opportunities currently are under development for therapy that may be driven or related to the DNAJB1-PRKACA fusion transcript or any therapeutic target identified from next-generation sequencing in patients with FLC.

Genomic Methods Identify Homologous Recombination Deficiency in Pancreas Adenocarcinoma and Optimize Treatment Selection

PURPOSE

Genomic methods can identify homologous recombination deficiency (HRD). Rigorous evaluation of their outcome association to DNA damage response-targeted therapies like platinum in pancreatic ductal adenocarcinoma (PDAC) is essential in maximizing therapeutic outcome.

EXPERIMENTAL DESIGN

We evaluated progression-free survival (PFS) and overall survival (OS) of patients with advanced-stage PDAC, who had both germline- and somatic-targeted gene sequencing. Homologous recombination gene mutations (HRm) were evaluated: BRCA1, BRCA2, PALB2, ATM, BAP1, BARD1, BLM, BRIP1, CHEK2, FAM175A, FANCA, FANCC, NBN, RAD50, RAD51, RAD51C, and RTEL1 HRm status was grouped as: (i) germline versus somatic; (ii) core (BRCAs and PALB2) versus non-core (other HRm); and (iii) monoallelic versus biallelic. Genomic instability was compared using large-scale state transition, signature 3, and tumor mutation burden.

RESULTS

Among 262 patients, 50 (19%) had HRD (15% germline and 4% somatic). Both groups were analyzed together due to lack of difference in their genomic instability and outcome. Median [95% confidence interval (CI)] follow-up was 21.9 (1.4-57.0) months. Median OS and PFS were 15.5 (14.6-19) and 7 (6.1-8.1) months, respectively. Patients with HRD had improved PFS compared with no HRD when treated with first-line (1L) platinum [HR, 0.44 (95% CI: 0.29-0.67); P < 0.01], but not with 1L-non-platinum. Multivariate analysis showed HRD patients had improved OS regardless of their first-line treatment, but most had platinum exposure during their course. Biallelic HRm (11%) and core HRm (12%) had higher genomic instability, which translated to improved PFS on first-line platinum (1L-platinum) versus 1L-non-platinum.

CONCLUSIONS

Pathogenic HRm identifies HRD in patients with PDAC with the best outcome when treated with 1L-platinum. Biallelic HRm and core HRm further enriched benefit from 1L-platinum from HRD.

Infigratinib in patients with advanced cholangiocarcinoma with FGFR2 gene fusions/translocations: the PROOF 301 trial

Cholangiocarcinoma is an aggressive malignancy with poor overall survival. Approximately 15% of intrahepatic cholangiocarcinomas contain FGFR alterations. Infigratinib is an oral FGFR 1-3 kinase inhibitor. Favorable results from a Phase II trial of infigratinib in advanced/metastatic FGFR-altered cholangiocarcinomas has led to its further investigation in the front-line setting. In this article we describe the design, objectives and rationale for PROOF 301, a Phase III multicenter, open label, randomized trial of infigratinib in comparison to standard of care gemcitabine and cisplatin in advanced/metastatic cholangiocarcinoma with FGFR2 translocations. The results of this study have the potential to define a new role for a chemotherapy-free, targeted therapy option in the front-line setting for these patients. Clinical Trial Registration: NCT03773302 (ClincalTrials.gov).

Hepatocellular carcinoma, novel therapies on the horizon

Hepatocellular carcinoma (HCC) is the most common primary liver cancer and is associated with high mortality rate. Incidence remains high due to the persistent prevalence of viral hepatitis, alcoholic cirrhosis, and non-alcoholic fatty liver disease (NFLD). Despite screening efforts, the majority of patients present with advanced disease, add to the high risk of recurrence after curative surgery. Conventional chemotherapy did not alter the nature history of advanced and metastatic HCC. The discovery of multiple tyrosine kinase inhibitors (TKIs) led to the approval of sorafenib as first efficacious therapy. A new era in the treatment paradigm of HCC is evolving. Since the advent of sorafenib as an active treatment option for patients presenting with advanced or metastatic disease, several agents have been examined. This was linked with many failures, and success stories to celebrate. Herein, we describe the historical progress and current advances of systemic therapies post-sorafenib. Lenvatinib, regorafenib, cabozantinib, ramucirumab, pembrolizumab, and nivolumab, are all presently added and available therapeutic options in the advanced setting. The evaluation of novel treatment combinations including anti-angiogenic, TKIs plus checkpoint inhibitors, add to dual checkpoint inhibitors is evolving rapidly starting with the advent of the combination of atezolizumab plus bevacizumab. Combining local and systemic therapies is being actively investigated, as an option for locally advanced disease conventionally treated with locoregional approaches. The horizon remains promising and continues to evolve for HCC a disease long considered with unmet needs.

Comparative Efficacy of Cabozantinib and Regorafenib for Advanced Hepatocellular Carcinoma

Background

No trials have compared cabozantinib and regorafenib for the second-line treatment of advanced hepatocellular carcinoma (HCC).

Objectives

Conduct a matching-adjusted indirect comparison (MAIC) of the efficacy and safety of second-line cabozantinib and regorafenib in patients with advanced HCC and disease progression after prior sorafenib.

Methods

The CELESTIAL and RESORCE trials were used for indirect comparison of second-line cabozantinib and regorafenib in advanced HCC. Population-level data were available for RESORCE, individual patient data (IPD) for CELESTIAL. To align with RESORCE, the CELESTIAL population was limited to patients who received first-line sorafenib only. To minimize potential effect-modifying population differences, the CELESTIAL IPD were weighted to balance the distribution of clinically relevant baseline characteristics with those of RESORCE. Overall survival (OS) and progression-free survival (PFS) were evaluated for the matching-adjusted second-line CELESTIAL population and compared with those for RESORCE using weighted Kaplan-Meier curves and parametric modeling. Rates of grade 3/4 treatment-emergent adverse events (TEAEs) affecting > 5% of patients in any study arm were compared.

Results

In the matching-adjusted second-line populations (CELESTIAL, effective sample size = 266; RESORCE, n = 573), median (95% confidence interval) OS was similar for cabozantinib and regorafenib (11.4 [8.9–17.0] versus 10.6 [9.1–12.1] months; p = 0.3474, log-rank test). Median PFS was longer for cabozantinib than regorafenib (5.6 [4.9–7.3] versus 3.1 [2.8–4.2] months; p = 0.0005, log-rank test). There was a trend for lower rates of some grade 3/4 TEAEs with regorafenib than with cabozantinib, which may reflect the exclusion of sorafenib-intolerant patients from RESORCE but not from CELESTIAL, a difference that the MAIC methods could not remove. Only diarrhea rates were statistically significantly lower for regorafenib (p  ≤ 0.001).

Conclusions

Cabozantinib may achieve similar OS and prolonged PFS compared with regorafenib in patients with progressive advanced HCC after prior sorafenib.

Electronic Supplementary Material

The online version of this article (10.1007/s12325-020-01378-y) contains supplementary material, which is available to authorized users.

Cabozantinib and regorafenib are treatments approved for some patients with advanced hepatocellular carcinoma (HCC), a type of liver cancer, after disease progression despite prior sorafenib treatment. Cabozantinib, regorafenib and sorafenib are tyrosine kinase inhibitors (TKIs), meaning that they slow cancer progression by targeting specific ways that tumors grow. Cabozantinib and regorafenib offer benefits to patients compared with placebo (i.e., no treatment) for those who have progressed despite sorafenib treatment. No clinical studies have compared cabozantinib and regorafenib directly. This study compared the efficacy and safety of cabozantinib and regorafenib using data from trials of each drug versus placebo: CELESTIAL for cabozantinib and RESORCE for regorafenib. These two trials were similar—both involved patients with progressive advanced HCC who had received previous cancer treatment. There were some important differences, but these were minimized using statistical methods (matching and adjustments/“weighting”) allowing outcomes to be meaningfully compared. One difference that could not be removed by the statistical methods was that patients who were intolerant to prior sorafenib were excluded from RESORCE but were eligible for the CELESTIAL trial. In the otherwise matched populations, treatment with cabozantinib was associated with similar overall survival and significantly longer progression-free survival than regorafenib. Rates of diarrhea were significantly lower for regorafenib than cabozantinib, suggesting that regorafenib may be better tolerated, but this may reflect the exclusion of sorafenib-intolerant patients from RESORCE. These findings cannot replace a head-to-head study, but may help in guiding decision-making between cabozantinib and regorafenib in patients with progressive advanced HCC after soraftenib treatment.

Broadening the therapeutic horizon of advanced biliary tract cancer through molecular characterisation

Biliary tract cancers (BTC) comprise a group of rare and heterogeneous poor-prognosis tumours with the incidence of intrahepatic cholangiocarcinoma increasing over recent years. Combination chemotherapy with gemcitabine and cisplatin is the established first-line treatment for advanced BTC with a significant but modest survival advantage over monotherapy. There remains no accepted standard treatment in the second-line setting, although recent results from a randomised study have shown a survival benefit with 5-fluorouracil and oxaliplatin chemotherapy. Historically, clinical trials investigating targeted therapies in unselected BTC have failed to demonstrate significant clinical benefit. More recently, advancement in molecular exploration of BTC has shed light on the complex biological heterogeneity within these tumours and has also identified actionable genomic aberrations, such as fibroblast growth factor receptor 2 (FGFR2) gene fusions, isocitrate dehydrogenase (IDH) and BRAF mutations, which offer promise with the anticipation of increased responses and durable clinical benefit in selected patients. Several targeted drugs have now entered clinical development with some encouraging results being seen. Here we review the current and rapidly evolving therapeutic landscape of advanced BTC, including targeted therapies and immunotherapy. We also discuss how recent efforts and successes in BTC are overcoming the obstacles typically associated with precision medicine in rare cancers. Ultimately, the management of advanced BTC is likely to become molecularly selected in the near future with the hope of finally improving the bleak prognosis of patients with this disease.

Ivosidenib in IDH1-mutant, chemotherapy-refractory cholangiocarcinoma (ClarIDHy): a multicentre, randomised, double-blind, placebo-controlled, phase 3 study

BACKGROUND

Isocitrate dehydrogenase 1 (IDH1) mutations occur in approximately 13% of patients with intrahepatic cholangiocarcinoma, a relatively uncommon cancer with a poor clinical outcome. The aim of this international phase 3 study was to assess the efficacy and safety of ivosidenib (AG-120)-a small-molecule targeted inhibitor of mutated IDH1-in patients with previously treated IDH1-mutant cholangiocarcinoma.

METHODS

This multicentre, randomised, double-blind, placebo-controlled, phase 3 study included patients from 49 hospitals in six countries aged at least 18 years with histologically confirmed, advanced, IDH1-mutant cholangiocarcinoma who had progressed on previous therapy, and had up to two previous treatment regimens for advanced disease, an Eastern Cooperative Oncology Group performance status score of 0 or 1, and a measurable lesion as defined by Response Evaluation Criteria in Solid Tumors version 1.1. Patients were randomly assigned (2:1) with a block size of 6 and stratified by number of previous systemic treatment regimens for advanced disease to oral ivosidenib 500 mg or matched placebo once daily in continuous 28-day cycles, by means of an interactive web-based response system. Placebo to ivosidenib crossover was permitted on radiological progression per investigator assessment. The primary endpoint was progression-free survival by independent central review. The intention-to-treat population was used for the primary efficacy analyses. Safety was assessed in all patients who had received at least one dose of ivosidenib or placebo. Enrolment is complete; this study is registered with ClinicalTrials.gov, NCT02989857.

FINDINGS

Between Feb 20, 2017, and Jan 31, 2019, 230 patients were assessed for eligibility, and as of the Jan 31, 2019 data cutoff date, 185 patients were randomly assigned to ivosidenib (n=124) or placebo (n=61). Median follow-up for progression-free survival was 6·9 months (IQR 2·8-10·9). Progression-free survival was significantly improved with ivosidenib compared with placebo (median 2·7 months [95% CI 1·6-4·2] vs 1·4 months [1·4-1·6]; hazard ratio 0·37; 95% CI 0·25-0·54; one-sided p<0·0001). The most common grade 3 or worse adverse event in both treatment groups was ascites (four [7%] of 59 patients receiving placebo and nine [7%] of 121 patients receiving ivosidenib). Serious adverse events were reported in 36 (30%) of 121 patients receiving ivosidenib and 13 (22%) of 59 patients receiving placebo. There were no treatment-related deaths.

INTERPRETATION

Progression-free survival was significantly improved with ivosidenib compared with placebo, and ivosidenib was well tolerated. This study shows the clinical benefit of targeting IDH1 mutations in advanced, IDH1-mutant cholangiocarcinoma.

FUNDING

Agios Pharmaceuticals.

Efficacy, tolerability, and biologic activity of a novel regimen of tremelimumab (T) in combination with durvalumab (D) for patients (pts) with advanced hepatocellular carcinoma (aHCC)

4508

Background: The combination of dual immune checkpoint inhibitors (ICI) T (anti–CTLA-4) and D (anti–PD-L1) showed tolerability with a promising objective response rate (ORR) in the initial cohort of this study (NCT02519348). Subsequent evaluation of pts with solid tumors treated with increasing doses of T suggested priming with a higher dose of T may induce a stronger immune response and enhance anti-tumor activity. Thus, the randomized expansion cohorts comprised 4 arms evaluating T and D as monotherapies and 2 T+D regimens, including a novel T+D regimen featuring a single, priming dose of T. Methods: ICI-naïve pts with aHCC who progressed on, were intolerant to, or refused sorafenib were randomized to one of two T+D combinations: T300+D (T 300 mg + D 1500 mg 1 dose followed by D Q4 weekly [Q4W]) or T75+D (T 75 mg Q4W + D 1500 mg Q4W [4 doses] followed by D Q4W); or single agent D (1500 mg Q4W) or T (750 mg Q4W). Safety was the primary endpoint. ORR by blinded, independent central review using RECIST v1.1, duration of response (DoR), circulating lymphocytes, and overall survival (OS) were assessed. Results: At data cut-off (09/02/2019), 332 pts were enrolled. Median follow-ups were 11.7 months (mo) for T300+D, 14.6 (T75+D), 8.9 (D), and 15.8 (T). Treatment-related adverse event (trAE) incidences are shown (Table); no deaths were attributed to trAEs for T300+D or T. The T300+D arm had the highest confirmed ORR (DoR not reached [NR]) and longest OS (Table). A unique proliferative T cell profile was identified for pts in the T300+D arm, suggesting additive biologic activity for the combination, and showed pts with an OR exhibited high cytotoxic (CD8) counts. Conclusions: The encouraging clinical activity and tolerable safety profile suggest T300+D provides the best benefit-risk profile as opposed to T75+D or monotherapies. The unique pharmacodynamic activity of the T300+D regimen further supports its use in aHCC. T300+D and D are being evaluated in the ongoing phase III HIMALAYA study (NCT03298451) in first-line HCC vs sorafenib. Funding: AstraZeneca. Clinical trial information: NCT02519348 . [Table: see text]

Clinical value of atezolizumab + bevacizumab for first-line unresectable hepatocellular carcinoma (HCC): A network meta-analysis

4585

Background: The IMbrave150 pivotal study in unresectable HCC showed superiority of atezolizumab + bevacizumab (atezo + bev) vs sorafenib for OS and PFS. Based on these data supporting first-line atezo + bev for HCC, we conducted a network meta-analysis (NMA) to compare the efficacy of atezo + bev with other systemic and local therapies approved for HCC. Methods: A systematic literature review identified randomized controlled trials in adults with locally advanced or metastatic HCC and no prior systemic therapy for HCC. Studies of therapies now approved for any line of HCC treatment with data reported for first-line treatment since sorafenib approval in 2007 were eligible. Screening of 8783 records yielded 55 trials for inclusion; 9 studies were eligible for the evidence network. Reported hazard ratios (HRs) for OS and PFS were extracted from published studies. The IMbrave150, REFLECT and CheckMate-459 study populations were considered sufficiently similar to compare. A generalized linear model with random effects was used to estimate indirect treatment effects. Informative priors for the heterogeneity of treatment effects across trials were adopted given the limited number of trials to inform each pairwise comparison. HRs with 95% credible intervals (CrIs) and Bayesian posterior probability of atezo + bev being superior to other treatments were calculated for each treatment comparison. The base case NMA compared the relative efficacy of atezo + bev vs sorafenib observed in the IMbrave150 study with the relative effect of other therapies. Sensitivity analyses were performed to compare subgroup results as appropriate based on disease etiology, extrahepatic spread and geography. Results: NMA results suggested improved OS with atezo + bev vs lenvatinib (HR, 0.63; 95% CrI: 0.32, 1.25; probability of atezo + bev being superior to lenvatinib: 93.7%) or nivolumab (HR, 0.68; 95% CrI: 0.35, 1.38; probability of atezo + bev being superior to nivolumab: 90.3%) and improved PFS with atezo + bev vs lenvatinib (HR, 0.91; 95% CrI: 0.23, 3.65; probability of atezo + bev being superior to lenvatinib: 61.5%) or nivolumab (HR, 0.63; 95% CrI: 0.16, 2.59; probability of atezo + bev being superior to nivolumab: 85.5%). Conclusions: This NMA suggested greater OS and PFS benefits with first-line atezo + bev treatment vs other therapies approved for treatment of unresectable HCC.

Landscape of DNA-damage-repair/homologous recombination deficiency (DDR/HRD) in hepatopancreaticobiliary (HPB) cancers

4620

Background: Biallelic HR-gene mutations (HRm) confer HRD and sensitivity to DDR-targeted therapies including platinum and PARPi in pancreatic cancer (PDAC). The landscape of DDR/HRD phenotypes in HPB cancers and their clinical implication is yet to be evaluated, the subject of this effort. Methods: Hybrid capture-based comprehensive genomic profiling was performed in a CLIA-certified, CAP-accredited lab (Foundation Medicine, Inc.) on up to 395 genes, including the HR-genes ( BRCA1/2, PALB2, RAD50/51B/C/D, MRE11, ATRX, ATR, ATM, BAP1, BRIP1, CHEK2, NBN, and FANCA). Putative DDR/HRD phenotype was assessed using percent genome under LOH (gLOH) (PMID: 28916367). Variant zygosity was assessed as previously described (PMID: 29415044). From an independent PDAC subgroup among HPB cancers, we evaluated their outcomes on first-line platinum. Results: From a total of 11,174 tumors, pathogenic DDR/HRm were identified in 18% (1980/11174) of HPB cancers, 15% (863/5941) of PDAC, 25% (744/2998) of cholangiocarcinoma, 15% (141/958) of hepatocellular carcinoma, and 17% (152/873) of gallbladder carcinoma. We observed a majority (63%) of DDR/HRm with LOH. Rigorous filtering for tumor purity and copy number quality metrics yielded 34% (4051/11774) cases evaluable. The median gLOH of any biallelic DDR/HRm was 12.9% compared to 8.8% in no DDR/HRm (p=5.7E-33). Strength of the association varied by gene, with the strongest association in BRCA1 (22.3, p=1.5E-10), BRCA2 (20.1, p=1.7E-35), RAD51C (16.7, p=7.8E-4), PALB2 (16.4, p=1.4E-5), BRIP1 (14.3, p=0.02), RAD51B (13.7, p=0.02), and ATM (13.6, p=7.7E-12) (Table). Most other DDR/HR-genes and monoallelic DDR/HRm had weak gLOH. PDAC accounted for 60% of this HPB dataset. In an independent dataset of PDAC at MSK (n=262), biallelic DDR/HRm patients (n=29, 11%) had mostly germline mutations and had significantly improved median PFS on first-line platinum vs. non-platinum (13.3 [95%CI: 9.57-NR] vs 3.8 [95%CI: 2.79-NR] months, p<0.0001). Conclusions: Biallelic DDR/HRm is a distinct population of HPB cancers beyond PDAC and may confer better phenotype in DDR-targeted treatment. Further independent validation is underway. [Table: see text]