Development of 2 Bromodomain and Extraterminal Inhibitors With Distinct Pharmacokinetic and Pharmacodynamic Profiles for the Treatment of Advanced Malignancies

PURPOSE

Bromodomain and extraterminal (BET) proteins are key epigenetic transcriptional regulators, inhibition of which may suppress oncogene expression. We report results from 2 independent first-in-human phase 1/2 dose-escalation and expansion, safety and tolerability studies of BET inhibitors INCB054329 (study INCB 54329-101; NCT02431260) and INCB057643 (study INCB 57643-101; NCT02711137).

PATIENTS AND METHODS

Patients (≥18 years) with advanced malignancies, ≥1 prior therapy, and adequate organ functions received oral INCB054329 (monotherapy) or INCB057643 (monotherapy or in combination with standard-of-care) in 21-day cycles (or 28-day cycles depending on standard-of-care combination). Primary endpoints were safety and tolerability.

RESULTS

Sixty-nine and 134 patients received INCB054329 and INCB057643, respectively. Study INCB 54329-101 has been completed; INCB 57643-101 is currently active, but not recruiting (no patients were receiving treatment as of January 8, 2019). Terminal elimination half-life was shorter for INCB054329 versus INCB057643 (mean [SD], 2.24 [2.03] vs. 11.1 [8.27] hours). INCB054329 demonstrated higher interpatient variability in oral clearance versus INCB057643 (CV%, 142% vs. 45.5%). Most common (>20%) any-grade treatment-related adverse events were similar for both drugs (INCB054329; INCB057643): nausea (35%; 30%), thrombocytopenia (33%; 32%), fatigue (29%; 30%), decreased appetite (26%; 22%). Two confirmed complete responses and 4 confirmed partial responses with INCB057643 were reported as best responses.

CONCLUSIONS

INCB057643 exhibited a more favorable PK profile versus INCB054329; exposure-dependent thrombocytopenia was observed with both drugs which limited the target inhibition that could be safely maintained. Further efforts are required to identify patient populations that can benefit most, and an optimal dosing scheme to maximize therapeutic index.

Recurrent hyperactive ESR1 fusion proteins in endocrine therapy-resistant breast cancer

Background

Estrogen receptor-positive (ER-positive) metastatic breast cancer is often intractable due to endocrine therapy resistance. Although ESR1 promoter switching events have been associated with endocrine-therapy resistance, recurrent ESR1 fusion proteins have yet to be identified in advanced breast cancer.

Patients and methods

To identify genomic structural rearrangements (REs) including gene fusions in acquired resistance, we undertook a multimodal sequencing effort in three breast cancer patient cohorts: (i) mate-pair and/or RNAseq in 6 patient-matched primary-metastatic tumors and 51 metastases, (ii) high coverage (>500×) comprehensive genomic profiling of 287-395 cancer-related genes across 9542 solid tumors (5216 from metastatic disease), and (iii) ultra-high coverage (>5000×) genomic profiling of 62 cancer-related genes in 254 ctDNA samples. In addition to traditional gene fusion detection methods (i.e. discordant reads, split reads), ESR1 REs were detected from targeted sequencing data by applying a novel algorithm (copyshift) that identifies major copy number shifts at rearrangement hotspots.

Results

We identify 88 ESR1 REs across 83 unique patients with direct confirmation of 9 ESR1 fusion proteins (including 2 via immunoblot). ESR1 REs are highly enriched in ER-positive, metastatic disease and co-occur with known ESR1 missense alterations, suggestive of polyclonal resistance. Importantly, all fusions result from a breakpoint in or near ESR1 intron 6 and therefore lack an intact ligand binding domain (LBD). In vitro characterization of three fusions reveals ligand-independence and hyperactivity dependent upon the 3' partner gene. Our lower-bound estimate of ESR1 fusions is at least 1% of metastatic solid breast cancers, the prevalence in ctDNA is at least 10× enriched. We postulate this enrichment may represent secondary resistance to more aggressive endocrine therapies applied to patients with ESR1 LBD missense alterations.

Conclusions

Collectively, these data indicate that N-terminal ESR1 fusions involving exons 6-7 are a recurrent driver of endocrine therapy resistance and are impervious to ER-targeted therapies.

Avelumab monotherapy as first-line or second-line treatment in patients with metastatic renal cell carcinoma: phase Ib results from the JAVELIN Solid Tumor trial

BACKGROUND

Antibodies targeting programmed death-1 (PD-1) or programmed death-ligand 1 (PD-L1) have shown clinical activity in the treatment of metastatic renal cell carcinoma (mRCC). This phase Ib cohort of the JAVELIN Solid Tumor trial assessed the efficacy and safety of avelumab (anti-PD-L1) monotherapy in patients with mRCC as either first-line (1 L) or second-line (2 L) treatment.

METHODS

Patients with mRCC with a clear-cell component who were treatment naive (1 L subgroup) or had disease progression after one prior line of therapy (2 L subgroup) received avelumab 10 mg/kg intravenous infusion every 2 weeks. Endpoints included confirmed best overall response, duration of response (DOR), progression-free survival (PFS), overall survival (OS), PD-L1 expression, and safety.

RESULTS

A total of 62 patients were enrolled in the 1 L subgroup, and 20 patients were enrolled in the 2 L subgroup. In the 1 L and 2 L subgroups, confirmed objective response rates were 16.1 and 10.0%, median DOR was 9.9 months (95% confidence interval [CI], 2.8-not evaluable) and not evaluable (95% CI, 6.9-not evaluable), median PFS was 8.3 months (95% CI, 5.5-9.5) and 5.6 months (95% CI, 2.3-9.6), and median OS was not evaluable (95% CI, not evaluable) and 16.9 months (95% CI, 8.3-not evaluable), respectively. Treatment-related adverse events (TRAEs) of any grade occurred in 51 patients in the 1 L subgroup (82.3%) and 14 patients in the 2 L subgroup (70.0%). Grade ≥ 3 TRAEs occurred in eight patients in the 1 L subgroup (12.9%) and one patient in the 2 L subgroup (5.0%). No treatment-related deaths occurred.

CONCLUSION

Avelumab showed clinical activity and a manageable safety profile in both the 1 L and 2 L treatment setting in patients with mRCC. These data support the use of avelumab in combination with other agents in mRCC.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01772004 ; registered 21 January, 2013.

Margetuximab with retifanlimab as first-line therapy in HER2+/PD-L1+ unresectable or metastatic gastroesophageal adenocarcinoma: MAHOGANY cohort A

BACKGROUND

Human epidermal growth factor receptor 2 (HER2)-positive metastatic gastric and gastroesophageal adenocarcinoma (GEA) is globally treated with chemotherapy plus trastuzumab. Novel therapeutic strategies strive to not only optimize efficacy, but also limit toxicities. In MAHOGANY cohort A, margetuximab, an Fc-engineered, anti-HER2 monoclonal antibody (mAb) was combined with retifanlimab, an anti-programmed cell death protein 1 mAb, in the first-line HER2-positive/programmed death-ligand 1 (PD-L1)-positive GEA.

PATIENTS AND METHODS

MAHOGANY cohort A part 1 is a single-arm trial to evaluate margetuximab plus retifanlimab in patients with HER2 immunohistochemistry 3+, PD-L1-positive (combined positive score ≥1%), and non-microsatellite instability-high tumors. Primary objectives for cohort A were safety/tolerability and the confirmed objective response rate (ORR).

RESULTS

As of 3 August 2021, 43 patients were enrolled and received margetuximab/retifanlimab. Nine grade 3 treatment-related adverse events (TRAEs) were reported in eight (18.6%) patients and eight serious TRAEs in seven (16.3%) patients. There were no grade 4/5 TRAEs. Three patients discontinued margetuximab/retifanlimab because of immune-related adverse events. The ORR by independent assessment was 53% [21/40 (95% confidence interval (CI) 36.1-68.5)], with a median duration of response of 10.3 months (95% CI 4.6-not evaluable); disease control rate was 73% [29/40 (95% CI 56.1-85.4)]. The study sponsor discontinued the study in advance of the planned enrollment when it became apparent that the study design would no longer meet the requirements for drug approval because of recent advances in the treatment of GEA.

CONCLUSIONS

The chemotherapy-free regimen of combined margetuximab/retifanlimab as first-line treatment in double biomarker-selected patients demonstrated a favorable toxicity profile compared with historical outcomes using chemotherapy plus trastuzumab. The ORR observed in this study compares favorably versus ORR observed with other chemotherapy-free approaches.

Signature program: a platform of basket trials

Investigating targeted therapies can be challenging due to diverse tumor mutations and slow patient accrual for clinical studies. The Signature Program is a series of 8 phase 2, agent-specific basket protocols using a rapid study start-up approach involving no predetermined study sites. Each protocol evaluated 1 agent (buparlisib, dovitinib, binimetinib, encorafenib, sonidegib, BGJ398, ceritinib, or ribociclib) in patients with solid or hematologic malignancies and an actionable mutation. The primary endpoint of each study was the clinical benefit rate (ie, complete or partial response, or stable disease) at 16 weeks. A total of 192 individual sites were opened in the United States, with a median start-up time of 3.6 weeks. The most common tumor types among the 595 treated patients were colorectal (9.2%), non-small cell lung adenocarcinoma (9.1%), and ovarian (8.4%). Frequent genetic alterations were in PIK3CA, RAS, p16, and PTEN. Overall, 30 partial or complete responses were observed with 6 compounds in 16 tumor types. The Signature Program presents a unique and successful approach for rapid signal finding across multiple tumors and allowed various agents to be evaluated in patients with rare alterations. Incorporating these program features in conventional studies could lead to improved trial efficiencies and patient outcomes.

Genomic profiling of cell-free circulating tumor DNA in patients with colorectal cancer and its fidelity to the genomics of the tumor biopsy

Background

Liquid biopsy offers the ability to non-invasively analyze the genome of a tumor through circulating tumor DNA (ctDNA) to identify targetable and prognostic genomic alterations. Few studies have rigorously analyzed ctDNA results and determined the fidelity with which they recapitulate the genomics of a sequenced tissue sample obtained from the same tumor. The clinical utility study (CUS) for the FoundationACT™ ctDNA assay (Foundation Medicine, Cambridge, MA, USA; NCT02620527) is a multi-center prospective clinical study for multiple solid tumor types to compare genomic profiling of paired tissue and blood samples from the same patient. In this subset of the study, paired specimens from 96 patients with colorectal cancer (CRC) were analyzed with comprehensive genomic profiling (CGP) of the tumor tissue sample (FoundationOne^®) and blood sample (FoundationACT™).

Methods

Both samples underwent CGP using the hybrid capture-based Illumina Hi-Seq technology. Maximum somatic allele frequency (MSAF) was used to estimate the fraction of ctDNA in the sample. The set of genes and targeted regions common to both tumor and liquid were compared for each subject.

Results

Among these patients, 61% were male; 74% had clinical stage IV disease, 19% had clinical stage III disease, and 7% had clinical stage II disease. Time between the tissue biopsy and liquid biopsy (range, 0-709 days) had a significant impact on the positive percent agreement (PPA) between the two assays. Eighty percent of cases had evidence of ctDNA in the blood (MSAF >0). For all cases with MSAF >0, 171 base substitutions and insertions/deletions (indels) were identified in the tumor, and 79% (PPA) of these identical alterations were also identified in matched ctDNA samples; PPA increased to 87% for cases <270 days between the tissue and liquid biopsy, 95% for <90 days, and 100% PPA for <30 days. All known and likely short variants in KRAS, NRAS, and BRAF were analyzed independently as testing of these genes is recommended by the National Comprehensive Cancer Network (NCCN) for patients with CRC and have therapeutic implications. For NCCN genes, PPA was 80% for all time points for short variants; PPA increased to 90% for cases <270 days between the tissue and liquid biopsy. There was high concordance for KRAS G12X between tissue and liquid: overall percent agreement (97%), PPA (93%), negative percent agreement (NPA) (100%), positive predictive value (PPV) (100%), and negative predictive value (NPV) (96%) for the <270 day cohort.

Conclusions

In cases where tumor tissue profiling is not possible, these results provide compelling evidence that genomic profiling of ctDNA in late stage CRC shows a high concordance with tumor tissue sequencing results and can be used to identify most clinically relevant alterations capable of guiding therapy for these patients.

Bintrafusp Alfa, a Bifunctional Fusion Protein Targeting TGF-β and PD-L1, in Patients With Non-Small Cell Lung Cancer Resistant or Refractory to Immune Checkpoint Inhibitors

BACKGROUND

Bintrafusp alfa is a first-in-class bifunctional fusion protein composed of the extracellular domain of transforming growth factor beta receptor II (a TGF-β "trap") fused to a human immunoglobulin G1 monoclonal antibody blocking programmed cell death 1 ligand 1 (PD-L1). We report the efficacy and safety in patients with non-small cell lung cancer (NSCLC) that progressed following anti-PD-(L)1 therapy.

MATERIALS AND METHODS

In this expansion cohort of NCT02517398-a global, open-label, phase I trial-adults with advanced NSCLC that progressed following chemotherapy and was primary refractory or had acquired resistance to anti-PD-(L)1 treatment received intravenous bintrafusp alfa 1200 mg every 2 weeks until confirmed progression, unacceptable toxicity, or trial withdrawal. The primary endpoint was best overall response (by Response Evaluation Criteria in Solid Tumors version 1.1 adjudicated by independent review committee); secondary endpoints included safety.

RESULTS

Eighty-three eligible patients (62 [74.7%] treated with ≥3 prior therapies) received bintrafusp alfa. Four patients (3 primary refractory, 1 acquired resistant) had confirmed partial responses (objective response rate, 4.8%; 95% CI, 1.3%-11.9%), and 9 had stable disease. Tumor cell PD-L1 expression was not associated with response. Nineteen patients (22.9%) experienced grade ≥3 treatment-related adverse events, most commonly asthenia (3 [3.6%]) and fatigue, eczema, and pruritus (2 each [2.4%]). One patient had grade 4 amylase increased. One patient died during treatment for pneumonia before initiation of bintrafusp alfa.

CONCLUSION

Although the primary endpoint was not met, bintrafusp alfa showed some clinical activity and a manageable safety profile in patients with heavily pretreated NSCLC, including prior anti-PD-(L)1 therapy. Tumor responses occurred irrespective of whether disease was primary refractory or had acquired resistance to prior anti-PD-(L)1 therapy.

Eflapegrastim, a Long-Acting Granulocyte-Colony Stimulating Factor for the Management of Chemotherapy-Induced Neutropenia: Results of a Phase III Trial

Background

Eflapegrastim, a novel, long‐acting recombinant human granulocyte‐colony stimulating factor (rhG‐CSF), consists of a rhG‐CSF analog conjugated to a human IgG4 Fc fragment via a short polyethylene glycol linker. Preclinical and phase I and II pharmacodynamic and pharmacokinetic data showed increased potency for neutrophil counts for eflapegrastim versus pegfilgrastim. This open‐label phase III trial compared the efficacy and safety of eflapegrastim with pegfilgrastim for reducing the risk of chemotherapy‐induced neutropenia.

Materials and Methods

Patients with early‐stage breast cancer were randomized 1:1 to fixed‐dose eflapegrastim 13.2 mg (3.6 mg G‐CSF) or standard pegfilgrastim (6 mg G‐CSF) following standard docetaxel plus cyclophosphamide chemotherapy for 4 cycles. The primary objective was to demonstrate the noninferiority of eflapegrastim compared with pegfilgrastim in mean duration of severe neutropenia (DSN; grade 4) in cycle 1.

Results

Eligible patients were randomized 1:1 to study arms (eflapegrastim, n = 196; pegfilgrastim, n = 210). The incidence of cycle 1 severe neutropenia was 16% (n = 31) for eflapegrastim versus 24% (n = 51) for pegfilgrastim, reducing the relative risk by 35% (p = .034). The difference in mean cycle 1 DSN (−0.148 day) met the primary endpoint of noninferiority (p < .0001) and also showed statistical superiority for eflapegrastim (p = .013). Noninferiority was maintained for the duration of treatment (all cycles, p < .0001), and secondary efficacy endpoints and safety results were also comparable for study arms.

Conclusion

These results demonstrate noninferiority and comparable safety for eflapegrastim at a lower G‐CSF dose versus pegfilgrastim. The potential for increased potency of eflapegrastim to deliver improved clinical benefit warrants further clinical study in patients at higher risk for CIN.

Implications for Practice

Chemotherapy‐induced neutropenia (CIN) remains a significant clinical dilemma for oncology patients who are striving to complete their prescribed chemotherapy regimen. In a randomized, phase III trial comparing eflapegrastim to pegfilgrastim in the prevention of CIN, the efficacy of eflapegrastim was noninferior to pegfilgrastim and had comparable safety. Nevertheless, the risk of CIN remains a great concern for patients undergoing chemotherapy, as the condition frequently results in chemotherapy delays, dose reductions, and treatment discontinuations.

Myelosuppression, particularly neutropenia, has presented a major challenge in cancer treatment since the introduction of cytotoxic chemotherapy. This article reports the results of a phase III trial that compared the efficacy and safety of eflapegrastim with pegfilgrastim for reducing the risk of chemotherapy‐induced neutropenia.

Tissue/Site-Agnostic Study of Ribociclib for Tumors With Cyclin D-CDK4/6 Pathway Genomic Alterations: A Phase II, Open-Label, Single-Arm Basket Study

PURPOSE

As part of the Novartis Signature Program, this study evaluated the efficacy of ribociclib (selective cyclin-dependent kinase 4/6 [CDK4/6] inhibitor) in patients with cyclin D-CDK4/6 pathway-aberrant tumors.

METHODS

This was a phase II, single-arm, signal-seeking study in patients with advanced malignancies that had progressed on or after standard treatment. Prior identification of tumor CDK4/6 mutation or amplification, CCND1/3 amplification, or CDKN2A mutation or loss was required. Clinical benefit (defined as the proportion of patients with response or stable disease at ≥ 16 weeks) was the primary end point.

RESULTS

From 61 centers in the United States, 106 patients (median age, 62.5 years) were enrolled across multiple malignancies. The patient population was heavily pretreated (median number of prior therapies, three; range, 0 to 19). Median progression-free survival was 1.8 months (95% CI, 1.8 to 1.9). In patients with solid tumors, the clinical benefit rate was 18.1% (n = 19 of 105) and the overall response rate was 2.9% (n = 3 of 105); three partial responses occurred in patients with adenocarcinoma (unknown primary), soft tissue sarcoma, and urothelial carcinoma. No tumor cohort met the prespecified criteria for success. The most common adverse events suspected to be related to treatment were neutropenia (30.2%; decreased neutrophils, 15.1%), fatigue (31.1%), and nausea (29.2%). Fatigue and nausea were typically mild. Only one incident of febrile neutropenia was experienced (grade 3).

CONCLUSION

No new or unexpected safety signals were observed in this heavily pretreated patient population. Although responses were seen in tumors with CCND1-CDK4/6 amplifications, the primary end point was not met, suggesting additional evaluation of ribociclib, possibly as combination therapy, is needed.

Abstract PD1-07: A Phase 2 study of poziotinib in patients with HER2-positive metastatic breast cancer heavily pre-treated with HER2-targeted therapy

Background: Poziotinib is a novel pan-HER inhibitor that irreversibly blocks the EGFR family of tyrosine-kinase receptors and inhibits the proliferation of tumor cells. This study evaluates the safety and clinical activity of poziotinib in patients with HER2-positive metastatic breast cancer (MBC) who received at least 2 therapies (trastuzumab and TDM-1) in dose-schedule ranging study. Methods: Patients were treated with oral poziotinib in 2 dose cohorts: 24mg daily 2 weeks/1 week off and 16mg daily continuously in a 21-day cycle. Dose reduction was allowed if toxicity observed. Patients continued treatment until disease progression, death, intolerable AE, or for a maximum of 24 months. The primary endpoint was the objective response rate (ORR), evaluated using RECIST 1.1. Secondary endpoints included disease control rate (DCR), duration of response (DOR), progression-free survival (PFS) and safety.

Results: Sixty-seven patients (33 in 24mg; 34 in 16mg) were enrolled (57 evaluable) in 2 cohorts; all patients either completed or discontinued (36 PD, 5 deaths due to PD, 16 AEs) the study with 1 completed 25 months of treatment. The median (range) age was 57 (29-94) years. Patients were heavily pretreated and the median (range) lines of previous therapy were 7 (2-13) and 4 (2-16) in 2 cohorts respectively [unique drugs 3 (2-5) and 3 (1-9)]; 75% received pertuzumab in addition to trastuzumab and TDM-1 and 37% received at least one tyrosine kinase inhibitor (TKI). The mean relative dose intensity was 57% and 51% with 67% and 47% had dose reductions in 2 cohorts respectively. Common Grade ≥3 treatment-related AEs were similar to other 2nd generation TKIs and include diarrhea (30%), rash (28%) and stomatitis (7%). The ORRs were 27% and 26% with the corresponding median DORs of 5.6 and 13 months respectively. 3 patients in 16mg dose had a CR and another 2 patients had an unconfirmed CR. The DCRs were 50% and 70% in 2 cohorts along with median PFS of 4.1 and 5.8 months respectively. The ORRs were 25% each in 2 cohorts in 24 and 20 heavily pre-treated patients with ≥4 lines of therapy that included trastuzumab, TDM1 and pertuzumab. The ORRs were 23% and 0% in 2 cohorts with 13 and 10 patients received at least one tyrosine kinase inhibitor (TKI) as the sample sizes were small to make any meaningful evaluation.

Conclusion: Poziotinib has demonstrated clinical activity in this dose-ranging study with tumor reduction shown in the majority of patients along with durable responses in this heavily pre-treated MBC patients. Safety profile was mechanism related and was similar to other 2nd generation TKIs.

Citation Format: Adam Brufsky, Malik Zulfiqar, Julio Peguero, Kate Lathrop, Gajanan Bhat, Francois Lebel. A Phase 2 study of poziotinib in patients with HER2-positive metastatic breast cancer heavily pre-treated with HER2-targeted therapy [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 PD1-07.

440 A Phase II study of eftilagimod alpha (soluble LAG-3 protein) and pembrolizumab in patients unselected for PD-L1 expression in first line metastatic head and neck squamous cell carcinoma (HNSCC)

Background

Eftilagimod alpha (efti) is a soluble LAG-3 protein targeting a subset of MHC class II molecules, effectively mediating antigen presenting cell (APC) and CD8 T-cell activation. Interim data from a phase II trial of efti plus pembrolizumab (TACTI-002) showed encouraging antitumor activity and manageable safety in patients treated for second line metastatic head and neck squamous cell carcinoma (HNSCC). TACTI-003 (NCT04811027) is the multicenter, open label, randomized phase II trial to investigate efti plus pembrolizumab in the first line setting for HNSCC patients.

Methods

A planned total of 154 patients (pts), unselected for PD-L1 expression, will be recruited into two cohorts (figure 1). In cohort A, CPS≥1 pts will be randomly assigned 1:1 to receive either efti (30 mg subcutaneously Q2W for initial 6 months, thereafter Q3W for up to 2 years) plus pembrolizumab (400 mg intravenously Q6W for up to two years) or pembrolizumab alone. CPS will be stratified (1–19 vs. ≥ 20 and ECOG 0 vs. 1). Cohort B will include pts with CPS<1 who will receive efti plus pembrolizumab without randomization. Imaging will be performed every 9 weeks. The primary end point (EP) is objective response rate (ORR) by RECIST1.1. Secondary EPs include overall survival, ORR according to iRECIST, time to and duration of response, disease control rate, progression free survival, occurrence of anti-efti -specific antibodies, safety, and quality of life. Exploratory endpoints comprise biomarkers. The study has been approved by relevant competent authorities, ethic committees and IRBs.

Abstarct 440 Figure 1

Trial design

Trial Registration

NCT04811027

Ethics Approval

The study was approved by relevant ethic committees and institutional review boards.

A phase 1b study of cofetuzumab pelidotin monotherapy in patients with PTK7-expressing recurrent non-small cell lung cancer

BACKGROUND

Protein tyrosine kinase 7 (PTK7) overexpression in lung cancer is associated with tumor progression. Cofetuzumab pelidotin (Cofe-P) is an antibody-drug conjugate comprising an anti-PTK7 antibody conjugated to a microtubule inhibitor. Herein, we report the results of a phase 1b study evaluating Cofe-P safety, efficacy, and pharmacokinetics in patients with recurrent non-small cell lung cancer (NSCLC).

METHODS

This signal-seeking phase 1b, open-label, multicenter, single-arm study enrolled patients with PTK7-expressing recurrent NSCLC. Cofe-P was administered at 2.8 mg/kg intravenously once every 3 weeks. The primary endpoint was objective response rate (ORR) and secondary endpoints were duration of response (DOR), progression-free survival (PFS), and overall survival (OS).

RESULTS

Overall, 65 patients received Cofe-P; 51 had PTK7 expression of ≥90 % tumor cells with ≥2+ staining intensity by immunohistochemistry. All patients reported adverse events (AEs), most commonly alopecia (52 %) and decreased neutrophil count (43 %); 69 % had grade ≥3 AEs, including grade ≥3 neutropenia in 25 %. Treatment-related AEs were reported in 94 % of patients; none were fatal. Overall, ORR was 18 %; in patients with PTK7 expression of ≥90 % tumor cells with ≥2+ staining and non-squamous epidermal growth factor receptor (EGFR) wild type or mutant, or squamous NSCLC, ORR was 21 %, 15 %, and 13 %, respectively. Overall, median DOR was 7.2 months, median PFS was 5.5 months, and median OS was 12.6 months; longest DOR (median 9.0 months), PFS (median 6.8 months), and OS (median 12.6 months) were in patients with non-squamous EGFR-mutant NSCLC.

CONCLUSIONS

Cofe-P demonstrated a manageable safety profile and preliminary efficacy across NSCLC histologies and EGFR mutation status. These data support PTK7 as a valid therapeutic target for NSCLC.

Intra-atrial placement of a mitral prosthesis in patients with severe mitral annular calcification

BACKGROUND AND AIM OF THE STUDY

The safety and durability of intra-atrial placement of mitral valve prostheses in patients with severe mitral annular calcification (MAC) were evaluated.

METHODS

A retrospective analysis was conducted of all patients with severe MAC who underwent intra-atrial placement of a mitral valve prosthesis between September 2008 and August 2011, by placement of an 8 mm Dacron graft sutured circumferentially around the sewing cuff. Both, intraoperative and postoperative echocardiography were performed to evaluate the adequacy of prosthesis placement and to assess the presence of mitral regurgitation (MR).

RESULTS

A total of six patients (three males, three females; mean age 78 +/- 9.7 years) was identified. The median EuroSCORE risk calculation was 14.5 (IQR 13-18), and three patients had a history of previous cardiac surgery. Three operations were performed via a minimally invasive approach. Three patients underwent concomitant coronary artery bypass graft surgery; one of these patients also underwent aortic valve replacement. All prostheses were placed successfully and no paravalvular leaks were observed postoperatively. There was one in-hospital mortality. The median aortic cross-clamp time was 176 min (IQR 156-190 min) and the median cardiopulmonary bypass time 178 min (IQR 156-218 min). The median preoperative versus postoperative MR grade was 3 (IQR 3-4) versus 0 (IQR 0-0). Follow up echocardiography was performed on two patients on postoperative days 20 and 70, respectively, but there was no evidence of MR. The median total length of hospital of stay was 11 days (IQR 4-19 days).

CONCLUSION

In patients requiring mitral valve replacement in which severe annular calcification prohibits standard valve surgery, the intra-atrial placement of a mitral valve prosthesis is a feasible option.

Abstract PD6-5: Profiling of ESR1-mutated metastatic breast cancers by FoundationOne® allows a broad genomic understanding for potential clinical implications

Background: Estrogen receptor (ER) inhibition is an important treatment option for advanced breast cancer (BC) pts. Recent studies describe recurring somatic mutations in codons 537 and 538 within the ligand-binding domain (LBD) of ∼ 20% of ER+ metastatic disease, but not treatment-naïve ER+ cancer or ER-negative disease, that render the ER constitutively active and confer partial resistance to endocrine agents. Few studies have described the clinicopathologic and genomic covariates that accompany the ESR1 genomic alterations (GAs). Correlating genomic events as captured by FoundationOne in pts with ESR1-mutated BCs with clinical history may provide clinical insight into these alterations.

Methods: Hybridization capture of 3769 exons of 236 cancer-related genes and 47 introns from 19 genes that are frequently rearranged in cancer were fully sequenced to high, uniform coverage using FoundationOne (Foundation Medicine, Cambridge, MA).

Results: 176 of the 2,208 (7.9%) BC pt cases harbored ESR1 alterations. 1127 short variants (SV) were detected in 176 patient samples for an average of 6.4 GA/sample. 16.5% SV (186/1127) were ESR1 GAs with an average of 1.0 ESR1 GAs/sample. ESR1 GAs consisted of base substitutions (77%) and amplifications (20%, median copy number 9X, range 6-28). Base substitutions occurred at codons 538 (71/145) and 537 (70/145) and at two other novel sites, 341 (2/145) and 563 (1/145). A patient-derived xenograft study suggested that tumors refractory to ER inhibitors and harboring ESR1 amplification could be responsive to higher doses of estradiol. (Li et al, Cell Reports, 2013). The most frequently co-occurring GAs were PIK3CA (37.5%), GATA3 (22.7%), TP53 (24.4%), MAP3K1 (10.2%) and CDH1 (7.9). Collection of data on tissue sites sequenced, treatments and outcomes on these pts with ESR1 GAs are ongoing. Of note, one pt had recurrent disease following adjuvant tamoxifen and letrozole. FoundationOne testing of her recurrent bony disease revealed an ESR1 Y537 alteration along with mutations in PIK3CA, APC, and RAD51. She has been on fulvestrant monotherapy with stable metastatic disease 13 + months.

Conclusions: We found through FoundationOne testing that ESR1 GAs are reasonably common in advanced BCs, with base substitutions accounting for 77% of ESR1 GAs and amplifications for 20%. Identification and characterization of ESR1-mutated advanced BC pts by comprehensive genomic profiling capable of detecting both base substitutions and copy number changes may identify clinically relevant GAs. Clinical correlation is pending.

Citation Format: Norma A Palma, Siraj Ali, Garrett Frampton, Kai Wang, Hannah Gilmore, Julio Peguero, Lyndsay N Harris, Massimo Cristofanilli, Juliann Chmielecki, Jeffrey S Ross, Deborah Morosini, Vincent A Miller, Phil J Stephens, Gary Palmer, Joyce O'Shaughnessy. Profiling of ESR1-mutated metastatic breast cancers by FoundationOne® allows a broad genomic understanding for potential clinical implications [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr PD6-5.

359 Results from a phase II study of eftilagimod alpha (soluble LAG-3 protein) and pembrolizumab in patients with PD-L1 unselected metastatic 2nd line head and neck squamous cell carcinoma (HNSCC)

Background

Eftilagimod alpha (efti) is a soluble LAG-3 protein targeting a subset of MHC class II, thus mediating antigen presenting cell (APC) and CD8 T-cell activation. Such stimulation of the dendritic cell network and resulting T cell recruitment by efti may lead to stronger anti-tumor responses than observed with pembrolizumab alone. We hereby report results of the 2nd line metastatic head and neck squamous cell carcinoma (HNSCC) cohort (part C) of the TACTI-002 phase II trial (NCT03625323).

Methods

Eligible patients (pts) with HNSCC, unselected for PD-L1 expression with disease progression on or after 1st line platinum-based therapy, received 30 mg subcutaneous efti Q2W for 24 weeks and 200 mg pembrolizumab Q3W for up to 2 years or until disease progression. The study used a Simon’s 2-stage design with objective response rate (ORR) as the primary endpoint (EP). Secondary EPs included tolerability, progression free survival (PFS), overall survival (OS), pharmacokinetics, pharmacodynamics, and immunogenicity. Tumor response was assessed Q9W. PD-L1 was assessed centrally (22C3 clone). The study was approved by ethic committees and institutional review boards.

Results

Between Mar 2019 and Jan 2021, 39 pts were enrolled (cut-off Apr 2021). The median age was 62 yrs (range 37–84) with 90% male pts. ECOG was 0 and 1 in 33% and 67%, respectively. Primary tumor location at diagnosis was oropharynx (36%), oral cavity (31%), hypopharynx (18%) and larynx (15%) with all PD-L1 subgroups (CPS< 1, ≥1 to ≤19; ≥20) being represented. All pts were pre-treated with platinum-based chemotherapy. Thirty-seven (37) pts were evaluated for response with ORR (iRECIST) of 30% (95% CI 16–47%) with 5 (14%) CRs; 6 (16%) PRs; 3 (8%) SDs; 17 (46%) PDs and 6 (16%) pts not evaluable. Median PFS was 2.1 months and 30+% were progression-free at 6 months. One patient (3%) discontinued due to pembro-related adverse event. The most common (>10%) treatment emergent adverse events were hypothyroidism (21%), cough (18%), asthenia (15%), fatigue (13%), anemia (13%), diarrhea (13%) and weight decreased (13%).

Conclusions

Efti in combination with pembrolizumab is safe, showing encouraging antitumor activity in platinum pre-treated, 2nd line HNSCC patients. For further investigation of this combination, a 1st line HNSCC trial (NCT04811027) has been initiated.

Trial Registration

NCT03625323

Ethics Approval

The study was approved by relevant ethic committees and institutional review boards

Abstract P2-14-12: Eflapegrastim, a novel long-acting granulocyte-colony stimulating factor: Integrated safety results in patients with early-stage breast cancer treated with TC chemotherapy

Background: Eflapegrastim (E) represents the first myeloid growth factor innovation in more than 15 years. A novel, long-acting recombinant human granulocyte-colony stimulating factor (rhG-CSF), E consists of a rhG-CSF analog conjugated to a human IgG4 Fc fragment via a polyethylene glycol linker. Preclinical and Phase I and II pharmacodynamic and pharmacokinetic data showed increased potency for E versus pegfilgrastim (P). Two independent randomized Phase III trials comparing fixed dose E and P (E 3.6 mg G-CSF and P 6.0 mg G-CSF) for the management of chemotherapy-induced neutropenia (CIN) have recently been completed. Both trials met the primary endpoint of non-inferiority for E vs P in Cycle 1 duration of severe neutropenia (P&lt;.001). Here we provide an integrated summary of the safety of E administered at a fixed dose in a pre-filled syringe.

Patients and Methods: Patients with early-stage breast cancer (ESBC) who were candidates for adjuvant or neoadjuvant chemotherapy were randomized 1:1 in two open-label Phase III trials to E 13.2 mg (3.6 mg G-CSF) or standard P (6 mg G-CSF) administered on Day 2 following TC (docetaxel/cyclophosphamide) chemotherapy on Day 1 of each of 4 cycles. Blood for CBC and serum chemistry was collected in every cycle. Safety assessments began with the first dose of TC and continued for one year after the last dose of study drug. AEs and laboratory values were graded according to NCI CTCAE version 4.03. Immunogenicity was assessed from blood samples collected on Day 1 of each cycle, at the end-of-treatment visit, and at 6- and 12-month follow-up visits.

Results: A total of 660 patients who received at least one dose of eflapegrastim (n=334) or pegfilgrastim (n=326) were included in this integrated safety analysis. The two treatment groups were well balanced for demographics and baseline disease characteristics. The mean age was 59y, ~40% were aged &gt;65y, ~54% weighed &gt;75kg, and ~80% were treated in the adjuvant setting. Median relative dose intensity for T and C was &gt;99% for both groups. A similar percentage of patients in both treatment groups discontinued treatment due to AEs (4% E vs 6% P), with 2% in each group discontinuing due to AEs related to E or P. Serious AEs were similar in both groups (15% each). Incidence of AEs irrespective of causality were also similar between groups (74% E vs. 72% P). No notable differences between groups were observed in the types of study-drug-related AEs. The majority of study-drug-related AEs occurred with an incidence ≤10% for both E and P. As expected with myeloid growth factors, study-drug-related AEs occurring in &gt;10% in either group were bone pain (E vs P: 33% vs 34%), arthralgia (15% vs 10%), back pain (14% vs 9%), myalgia (14% vs 9%), and headache (11% vs 8%). Incidence of febrile neutropenia and neutropenic complications were similar and less than 5% in each treatment group. No leukocytosis, splenic rupture, or anaphylaxis was reported in any patient receiving E or P. The overall incidence of immunogenicity was similar in both groups and there was no demonstrable impact on clinical safety or efficacy.

Conclusions: Two large, randomized Phase III trials (Total n=660) of E vs P administered once-per-cycle showed E at a lower G-CSF dose to be safe and effective for the prophylaxis of CIN in patients with ESBC receiving TC chemotherapy. E is a novel long-acting rhG-CSF with increased potency and similar toxicity to P and may provide an attractive alternative for growth factor support of patients at high risk for CIN-related complications.

Citation Format: Lee S Schwartzberg, Gajanan Bhat, Julio Peguero, Richy Agajanian, Jayaram Bharadwaj, Alvaro Restrepo, Osama Hlalah, Inderjit Mehmi, Shanta Chawla, Francois Lebel, Patrick W Cobb. Eflapegrastim, a novel long-acting granulocyte-colony stimulating factor: Integrated safety results in patients with early-stage breast cancer treated with TC chemotherapy [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-14-12.

Eftilagimod Alpha (Soluble LAG3 Protein) Combined with Pembrolizumab as Second-Line Therapy for Patients with Metastatic Head and Neck Squamous Cell Carcinoma

PURPOSE

Eftilagimod alpha (efti), a soluble LAG3 protein, activates antigen-presenting cells (APC) and downstream T cells. TACTI-002 (part C) evaluated whether combining efti with pembrolizumab led to strong antitumor responses in patients with second-line recurrent or metastatic head and neck squamous cell carcinoma (R/M HNSCC) while demonstrating good tolerability.

PATIENTS AND METHODS

In this multinational phase II trial using Simon's two-stage design, patients who were PD-L(1)-naïve with R/M HNSCC who had failed first-line platinum-based therapy, unselected for PD-L1, received intravenous pembrolizumab (200 mg, once every 2 weeks) combined with subcutaneous efti (30 mg once every 2 weeks for 24 weeks and once every 3 weeks thereafter). The primary endpoint was objective response rate per RECIST 1.1 modified for immune-based therapy by investigator assessment. Additional endpoints included duration of response, progression-free survival, overall survival, and tolerability. Pharmacodynamic effects (absolute lymphocyte count) and Th1 cytokine biomarkers (IFNγ/CXCL10)] were evaluated in liquid biopsies.

RESULTS

Between March 2019 and January 2021, 39 patients were enrolled; 37 were evaluated for response. All patients received prior chemotherapy, and 40.5% were pretreated with cetuximab; 53.1% of patients had PD-L1 combined positive score <20. With a median follow-up of 38.8 months, the objective response rate was 29.7%, including 13.5% complete responders. The median duration of response was not reached. Rapid and sustained absolute lymphocyte count increase was observed in patients who had an objective response. Th1 biomarkers increased sustainably after first treatment. No unexpected safety signals were observed.

CONCLUSIONS

Efti plus pembrolizumab was safe and showed encouraging antitumor activity and pharmacodynamic effects in patients with second-line head and neck squamous cell carcinoma (HNSCC), thus supporting further evaluation of this combination in earlier treatment lines.

Proximal duodeno-jejunostomy for the safe management of the difficult duodenal stump

Seven patients with peptic ulcer disease had severe scarring of the duodenum, making its closure at the time of gastrectomy difficult. They were managed intraoperatively with proximal duodeno-jejunostomy as a means to avoid the catastrophic complication of disruption of the duodenal stump closure with its consequent peritonitis. The jejunum used for this anastomosis was an extension of the long limb of a Roux en Y which is brought up to perform the gastrojejunostomy. The end to end duodeno-jejunostomy is performed proximal to a side to side gastrojejunostomy, hence the name, proximal duodeno Jejunostomy. These seven patients had no unexpected immediate postoperative complications during the thirty days following surgery and were all discharged from the hospital well. During the same three and a half year period twenty five other patients were submitted to gastrectomy and had two duodenal stump leaks after conventional closures. One patient died and the other survived after prolonged intensive care stay. These differences were not statistically significant. These duodenojejunostomies are non-functional anastomoses and should consequently stricture, but in one patient it remained open and he developed bile reflux gastritis in spite of the Roux en Y gastrojejunostomy constructed to avoid this complication. These anastomoses should be constructed as stenotic as possible.