HER2-expressing Solid Tumors Research Articles

Efficacy and safety of trastuzumab deruxtecan among patients with HER2-expressing solid tumors: Biomarker and subgroup analyses from the cervical, endometrial, and ovarian cancer cohorts of the DESTINY-PanTumor02 study

Efficacy and safety of trastuzumab deruxtecan among patients with HER2-expressing solid tumors: Biomarker and subgroup analyses from the cervical, endometrial, and ovarian cancer cohorts of the DESTINY-PanTumor02 study

OA16.04 Preliminary Results from a FIH Study of GQ1005, A Novel HER2-ADC, in Patients with Advanced HER2-Expressing Solid Tumors and HER2-Mutated NSCLC

OA16.04 Preliminary Results from a FIH Study of GQ1005, A Novel HER2-ADC, in Patients with Advanced HER2-Expressing Solid Tumors and HER2-Mutated NSCLC

Efficacy of Trastuzumab Deruxtecan in HER2-Expressing Solid Tumors by Enrollment HER2 IHC Status: Post Hoc Analysis of DESTINY-PanTumor02.

DESTINY-PanTumor02 (NCT04482309) evaluated the efficacy and safety of trastuzumab deruxtecan (T-DXd) in pretreated patients with human epidermal growth factor receptor 2 (HER2)-expressing [immunohistochemistry (IHC) 3+/2+] solid tumors across seven cohorts: endometrial, cervical, ovarian, bladder, biliary tract, pancreatic, and other. Subgroup analyses by HER2 status were previously reported by central HER2 IHC testing, determined at enrollment or confirmed retrospectively. Reflecting the testing methods available in clinical practice, most patients (n=202; 75.7%) were enrolled based on local HER2 IHC testing. Here, we report outcomes by HER2 IHC status as determined by the local or central test results used for study enrollment. This phase 2, open-label study evaluated T-DXd (5.4mg/kg once every 3weeks) for HER2-expressing (IHC 3+/2+by local or central testing) locally advanced or metastatic disease after≥1 systemic treatment or without alternative treatments. The primary endpoint was investigator-assessed confirmed objective response rate (ORR). Secondary endpoints included safety, duration of response (DOR), progression-free survival (PFS), and overall survival. In total, 111 (41.6%) and 151 (56.6%) patients were enrolled with IHC 3+and IHC 2+tumors, respectively. In patients with IHC 3+tumors, investigator-assessed confirmed ORR was 51.4% [95% confidence interval (CI) 41.7, 61.0], and median DOR was 14.2months (95% CI 10.3, 23.6). In patients with IHC 2+tumors, investigator-assessed ORR was 26.5% (95% CI 19.6, 34.3), and median DOR was 9.8months (95% CI 4.5, 12.6). Safety was consistent with the known profile of T-DXd. In line with previously reported results, T-DXd demonstrated clinically meaningful benefit in patients with HER2-expressing tumors, with the greatest benefit in patients with IHC 3+tumors. These data support the antitumor activity of T-DXd in HER2-expressing solid tumors, irrespective of whether patients are identified by local or central HER2 IHC testing.

OST-HER2 Shows Positive Data in Phase 1 Clinical Trial of HER2-expressing Solid Tumors

OST-HER2, a biologic therapeutic candidate being developed by OS Therapies, is a Listeriamonocytogenes (Lm-) vector-based off-the-shelf immunotherapeutic vaccine designed to prevent metastasis, delay recurrence, and increase overall survival in patients with osteosarcoma and other solid tumors. The proposed OST-HER2 mechanism of action is based on innate and adaptive immune stimulating responses activated by the Lm vector. This treatment generates T-cells that can eliminate or slow potential micrometastases that can grow into recurrent osteosarcoma and other solid tumors, including breast cancer.

HER2-targeting antibody drug conjugate FS-1502 in HER2-expressing metastatic breast cancer: a phase 1a/1b trial

Currently approved HER2-targeting antibody-drug conjugates (ADCs) for HER2-positive breast cancer (BC) are associated with safety concerns. In this multicenter, single-arm, dose-escalation (phase 1a) and dose-expansion (phase 1b) phase 1 trial (NCT03944499), patients with HER2-expressing advanced solid tumors received FS-1502 (an anti-HER2 ADC) with a 3 + 3 design in phase 1a; patients with metastatic HER2-positive BC received FS-1502 at the recommended phase 2 dose (RP2D) in phase 1b. The primary end points were dose-limiting toxicities (DLTs), maximum tolerated dose (MTD) and RP2D for phase 1a and objective response rate (ORR) for phase 1b. A total of 150 patients with HER2-expressing solid tumors (n = 5) and BC (n = 145) were enrolled (female, n = 146, 97.3%). One DLT each was reported at 3.0 and 3.5 mg/kg; the MTD was not reached. The RP2D was 2.3 mg/kg once every 3 weeks. Five (3.3%) patients experienced pneumonitis; four (2.7%) had grade 3 reversible ocular events. Of 67 HER2-positive BC patients receiving the RP2D, the best ORR was 53.7% (95% CI, 41.1-66.0%), including PRs confirmed (confirmed ORR, 37.5%) and pending for confirmation. FS-1502 was well tolerated with limited ocular and pulmonary findings and demonstrated promising antitumor activity in HER2-positive BC patients.

A phase Ia/b trial of ARX788 combined with toripalimab for HER2-low advanced breast cancer (ABC) and other HER2-expressing solid tumors.

e13159 Background: ARX788 has been proved with superior PFS compared with a combination of capecitabine and lapatinib in the randomized phase Ⅱ/Ⅲ study for HER2-positive ABC (Ambrx, 2023). Here we report the preliminary safety and efficacy of ARX788 plus toripalimab in HER2-low ABC and other HER2-expressing solid tumors. Methods: This was a phase Ⅰ study conducted in China. Eligible patients were HER2-low (IHC2+ and FISH- or IHC1+) ABC or HER2-expressing (IHC 2+ or 3+) solid tumors. Dose exploration with ARX788 is 1.3, 1.5mg/kg, IV, Q3W plus toripalimab 240mg, IV, Q3W. Primary endpoint was safety and RP2D of Ⅰa and efficacy of Ⅰb. Results: Totally, 12 patients were enrolled in phase Ⅰa, 10 patients were diagnosed with ABC, 1 was diagnosed with BTC and 1 was CRC. 6 patients each were treated with 1.3 and 1.5mg/kg. No DLTs were observed. 12 patients (100%) experienced ≥1 ADRs. The most common (≥20%) ADRs were AST increased (75%), platelet count decreased (75%), alopecia (41.67%), white blood cell count decreased (25%), ALT increased (25%), dry eye (25%), interstitial lung disease (25%) and neutrophil count decreased (25%). 1.5mg/kg dose level showed a slightly higher incidence in hematologic toxicities, interstitial lung disease and alopecia. Grade 3 ADRs occurred in 8 patients (66.67%) with equal incidence of the 2 dose levels, those were ocular events (41.7%, 2 of each level), interstitial lung disease (8.3%, 1 of 1.5mg/kg), platelet count decreased (8.3%, 1 of 1.5mg/kg), jaundice (8.3%, 1 of 1.3mg/kg) and immune-mediated myocarditis (8.3%, 1 of 1.3mg/kg). No grade 4 or 5 ADRs occurred. All ADRs were manageable and have recovered. ORR was 41.7% in 12 patients, with 33.3% and 50% in 1.3 and 1.5mg/kg dose level. In 10 patients with ABC, ORR was 50%, with 40% and 60% in each level. DCR was 83.33% and 100%, respectively. Thus, 1.5mg/kg was determined as RP2D and phase Ⅰb is ongoing with HER2-low ABC patients. Conclusions: ARX788 with 1.5mg/kg combined with toripalimab was shown acceptable safety profile with promising efficacy, no significant increase in adverse reactions or serious unexpected immune-related adverse reactions compared with ARX788 monotherapy, which supports further evaluation for HER2-low ABC in a larger sample in Ⅰb trial. Clinical trial information: CTR20222247.

Efficacy and safety of trastuzumab deruxtecan (T-DXd) in patients (pts) with HER2-expressing solid tumors: Results from the bladder cohort of the DESTINY-PanTumor02 (DP-02) study.

4565 Background: In DP-02, T-DXd showed robust responses and clinically meaningful survival outcomes in 267 pretreated pts with HER2-expressing solid tumors; the objective response rate (ORR) by investigator (INV) was 37.1% (95% CI 31.3, 43.2). Here we report subgroup analyses in the bladder cohort (urothelial carcinoma including transitional cell carcinoma of the renal pelvis, ureter, urinary bladder, or urethra), and characterize pts with an objective response (OR). Methods: This open-label, Phase 2 study (NCT04482309) evaluated T-DXd (5.4 mg/kg Q3W) in pts with HER2-expressing (immunohistochemistry [IHC] 3+/2+ by local or central testing) locally advanced/metastatic disease after ≥1 systemic treatment (Tx), or without Tx options. The primary endpoint was confirmed ORR by INV. Secondary endpoints included duration of response (DOR), progression-free survival (PFS), disease control rate (DCR), and safety. Exploratory endpoints included efficacy outcomes according to HER2 expression. Results: At data cutoff (June 2023), 41 pts with urothelial cancers had received T-DXd (median [m] follow up [range]: 12.65 [0.4–26.8] months); 27 (65.9%) had received ≥2 prior Tx regimens. 16/41 pts (39.0%; 95% CI 24.2, 55.5) had a confirmed OR by INV; 12 responders had received ≥2 prior Tx regimens, 14 had received prior immunotherapy Tx, and 14 had known PD-L1 immune cell status ≥1%. The Table shows efficacy outcomes in all pts and by HER2 expression (central testing). Grade (G) ≥3 drug-related adverse events occurred in 17/41 (41.5%) pts. Adjudicated drug-related interstitial lung disease / pneumonitis occurred in 4/41 (9.8%) pts (n=1 G1; n=3 G2). Conclusions: T-DXd showed clinically meaningful responses in pretreated pts with urothelial cancers, including across HER2 expression levels (IHC 3+ and 2+). Safety was consistent with the known profile. These data support further evaluation of T-DXd as a potential Tx for pretreated pts with HER2-expressing urothelial cancers. Clinical trial information: NCT04482309 . [Table: see text]

Prevalence of HER-2 expression and correlation with clinicopathological features in gynecological cancer: A single-center retrospective study in China.

e17500 Background: Targeted therapy for human epidermal growth factor receptor 2 (HER2) has become a standard of care in several HER2-expressing solid tumors. Nonetheless, there remains an unmet need for effective treatment, for instance, anti-HER2 antibody-drug conjugates (ADCs), in advanced stage gynecological cancer. In this context, we presented a retrospective study on the incidence of HER2 expression in primary gynecological cancer based on a single-center data from southwestern China. Methods: Paraffin-embedded tumor tissue blocks, clinicopathological, and survival data of gynecological cancer patients were collected from Chongqing University Cancer Hospital. HER2 IHC scoring was carried out according to the updated ASCO/CAP guidelines for breast and gastroesophageal adenocarcinoma by two pathologists independently. Data analysis was performed using SPSS v.24. Results: A total of 104 cases of cervical cancer, 102 cases of endometrial cancer and 103 cases of ovarian cancer were included between 2019 and 2023. HER2 expression was detected in 31.7% samples, with scores of 1+, 2+, and 3+ in 23.9% (74/309: 36/104, 16/102, 22/103), 5.8% (18/309: 7/104, 7/102, 4/103), and 1.9% (6/309: 2/104, 1/102, 3/103) of patients, respectively. Notably, ultra-low HER2 expression with incomplete and faint staining in ≤10% of tumor cells was observed in 41.1% (127/309: 37/104, 53/102, 37/103) of patients. Metastasis and lymphovascular invasion were associated with elevated HER2 expression in endometrial cancer (p=0.037, 0.040, respectively), while a larger tumor size was associated with elevated HER2 expression in cervical cancer (p=0.004). However, no positive association between HER2 status and overall survival (OS) was found in cervical, endometrial or ovarian cancer. In our cohort, metastasis was the only risk factor related to reduced OS of gynecological cancer patients by COX regression analysis (HR=14.00, 95%CI=1.32-148.21, p=0.028). Conclusions: Our data revealed a considerable number of patients with HER2-low and ultra-low gynecological cancer. It might represent a significant portion in real-world scenarios and warrant more consideration in selecting candidates for HER2-targeted ADCs, especially for those with relapsed or refractory conditions. Given the inherent challenge in interpretation, the study highlights the necessity for a consensus on evaluating HER2 immuno-staining results in gynecological cancer. Clinical trial information: MR-50-23-019676 . [Table: see text]

Abstract 6352: Preclinical discovery of ARX622: A site-specific, TLR7 agonist, HER2-targeted immune-stimulatory antibody drug conjugate for treatment of multiple solid tumor types

Abstract Traditional antibody-drug conjugates leverage the specificity of antibodies to deliver cytotoxic payloads to tumor microenvironments (TMEs), thereby reducing systemic toxicities associated with non-targeted chemotherapeutics. Analogously, a novel class of immune-stimulating antibody conjugates (ISACs) has recently emerged to selectively deliver synthetic immune agonists to the TME without systemic immune activation. The first generation of ISACs and the majority of approved and investigational ADCs contain payloads linked to native lysine or cysteine residues, which can lead to heterogenous drug-antibody ratios (DARs), reduced antibody stability, and labile conjugation, all of which limit therapeutic index. Here we describe the generation and preclinical characterization of ARX622, a site-specific TLR7-selective agonist ISAC targeting HER2. To avoid the instability issues of previous generation ADCs and ISACs, ARX622 has a homogenous and stable DAR via oxime bond-mediated payload conjugation to a synthetic amino acid, para-acetyl phenylalanine (pAF), which is recombinantly incorporated at defined heavy chain positions. Similar to cytotoxic ADCs built on this site-specific conjugation platform, ARX622 ISAC and total mAb pharmacokinetic (PK) profiles in non-human primates (NHPs) are indistinguishable, demonstrating in vivo stability and minimal payload deconjugation. Accordingly, ARX622 displays an extended PK profile in mice compared to a DAR-matched random cysteine ISAC containing the same antibody and payload. In the presence of HER2-expressing cells, ARX622 selectively induces proinflammatory cytokine production, type I and III IFN secretion, and APC maturation. In a syngeneic tumor model, ARX622 promotes complete tumor regressions, immunologic memory, and epitope spreading. In xenograft systems, single doses of ARX622 induce complete regression of large, established tumors (>1000mm3), and robustly inhibit tumor growth in mice that have progressed through prior treatment with HER2-targeted mAbs or ADCs. In HER2-low xenografts, ARX622 monotherapy inhibits tumor growth, and promotes complete regression of late-stage (800mm3) tumors when sequentially combined with a HER2-ADC. Based on PK data at efficacious doses in mice and tolerated exposures in NHP toxicity studies, ARX622 has an estimated therapeutic index of ~60x. Taken together, ARX622’s mAb-like properties, high stability, broad immune mechanism induction, strong anti-tumor activity alone or in combination with ADCs, and wide therapeutic index make it a strong candidate for further development toward treating patients with a variety of HER2-expressing solid tumors. Citation Format: David Mills, Ji Young Kim, Erica Wood, Keith Tatsukawa, Nick Knudsen, Jay Nelson, Lillian Skidmore, Kedar GC, Hon Tran, Manoj Pal, Hamidreza Hashemi, Ying Buechler, Shawn Zhang, Dan O'Connor. Preclinical discovery of ARX622: A site-specific, TLR7 agonist, HER2-targeted immune-stimulatory antibody drug conjugate for treatment of multiple solid tumor types [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6352.

Trastuzumab deruxtecan in patients with human epidermal growth factor receptor 2-expressing salivary gland carcinoma: a pooled analysis of two phase I studies.

HER2-expressing salivary gland carcinoma (SGC) is associated with poor prognosis. Trastuzumab deruxtecan (T-DXd, DS-8201) has shown evidence of antitumor activity for several HER2-expressing solid tumors in multiple studies. This study aimed to present the efficacy and safety of T-DXd in patients with HER2-expressing SGC from a pooled analysis. Patients with HER2-expressing SGC were pooled from two phase I, open-label studies of T-DXd: a two-phase, multiple-dose, first-in-human study (NCT02564900) and a single-sequence crossover drug-drug interaction study (NCT03383692). Endpoints included efficacy (objective response rate [ORR], duration of response [DoR] and progression-free survival [PFS]) and safety. This pooled analysis included 17 patients with SGC (median age: 57 years; male: 88.2%); median (range) follow-up duration was 12.0 (2.3-‍34.8) months. Among these patients, 14 had received prior HER2-targeted agents and 13 had undergone prior radiotherapy. The investigator-assessed confirmed ORR was 58.8% (95% confidence interval [CI], 32.9-‍81.6). The median (95% CI) DoR and PFS were 17.6 months (4.0 to not evaluable [NE]) and 20.5 months (11.1-NE), respectively. All 17 patients reported treatment-emergent adverse events (TEAEs); 76.5% reported TEAEs of grade ≥3. The most common TEAEs were decreased appetite (94.1%), nausea (88.2%) and neutrophil count decreased (76.5%). Of the 17 patients, five (29.4%) reported adjudicated drug-related interstitial lung disease (grade 1, n = 3; grade 2, n =1; grade 3, n = 1). The results of this pooled analysis provide evidence that clinical benefit is achievable with T-DXd in patients with HER2-expressing SGC. FIH study, NCT02564900; DDI study, NCT03383692.

RC48-ADC treatment for patients with HER2-expressing locally advanced or metastatic solid tumors: a real-world study

BackgroundRC48-antibody-drug conjugates (ADC) link humanized anti-HER2 immunoglobulin with monomethyl auristatin E (MMAE). Clinical trials suggest promising antitumor activity in HER2-expressing solid tumors. This study probes RC48-ADC’s efficacy and safety in patients with HER2-expressing advanced or metastatic solid tumors.MethodData was collected from 23 advanced cancer patients treated with RC48-ADC at our oncology center between July 2021 and December 2022. These patients exhibited at least 1 + expression of HER2 immunohistochemistry, had previously experienced at least one failed systemic chemotherapy, and were treated with RC48-ADC until the occurrence of intolerable adverse reactions or disease progression. The primary endpoint was the disease control rate (DCR), and secondary endpoints included progression-free survival (PFS), objective response rate (ORR), and safety.Results23 of 25 screened patients received RC48 treatment. The ORR was 43.5% (95% CI, 23.2-63.7%) with a median PFS of 6.0 months (95% CI, 4.8–7.4). In the low-to-medium HER2 expression subgroup, ORR was 37.5%, median PFS 5.75 months. In the high HER2 expression subgroup, ORR was 57.1%, median PFS 7 months. For the cohort combining RC48 with PD-1 inhibitors, ORR was 53.8%, median PFS 8 months. In the concurrent local radiation therapy subgroup, ORR was 40.0%, median PFS 6.0 months. Treatment-related adverse events (TRAEs) were anemia (60.8%), leukopenia (56.2%), raised transaminases (52.17%), and neutropenia (43.5%). Five patients (21.7%) experienced Grade 3 symptoms, including anemia (21.7%) and neutropenia (14.0%). No Grade 4 adverse reactions or deaths were reported.ConclusionRC48-ADC shows promising efficacy and manageable safety in HER2-expressing advanced or metastatic solid tumor patients.

74MO Trastuzumab deruxtecan (T-DXd) for pretreated patients (pts) with HER2-expressing solid tumors: Primary analysis from the DESTINY-PanTumor02 (DP-02) study

74MO Trastuzumab deruxtecan (T-DXd) for pretreated patients (pts) with HER2-expressing solid tumors: Primary analysis from the DESTINY-PanTumor02 (DP-02) study

148P DESTINY-PanTumor02 study of trastuzumab deruxtecan (T-DXd) in patients (pts) with HER2-expressing solid tumors: Exploratory biomarker analyses of HER2 expression and gene amplification in tissue and plasma

148P DESTINY-PanTumor02 study of trastuzumab deruxtecan (T-DXd) in patients (pts) with HER2-expressing solid tumors: Exploratory biomarker analyses of HER2 expression and gene amplification in tissue and plasma

1075TiP A phase I/Ib open-label, first-in-human, single agent, dose escalation and expansion study of a HER2-targeted T cell engager (SAR443216) in patients with relapsed/refractory HER2-expressing solid tumors

1075TiP A phase I/Ib open-label, first-in-human, single agent, dose escalation and expansion study of a HER2-targeted T cell engager (SAR443216) in patients with relapsed/refractory HER2-expressing solid tumors

LBA34 Trastuzumab deruxtecan (T-DXd) for pretreated patients (pts) with HER2-expressing solid tumors: Primary analysis from the DESTINY-PanTumor02 (DP-02) study

LBA34 Trastuzumab deruxtecan (T-DXd) for pretreated patients (pts) with HER2-expressing solid tumors: Primary analysis from the DESTINY-PanTumor02 (DP-02) study

657MO Recommended phase II dose (RP2D) selection and pharmacodynamic (PD) data of the first-in-human immune-stimulating antibody conjugate (ISAC) BDC-1001 in patients (pts) with advanced HER2-expressing solid tumors

657MO Recommended phase II dose (RP2D) selection and pharmacodynamic (PD) data of the first-in-human immune-stimulating antibody conjugate (ISAC) BDC-1001 in patients (pts) with advanced HER2-expressing solid tumors

Efficacy and safety of trastuzumab deruxtecan (T-DXd) in patients (pts) with HER2-expressing solid tumors: DESTINY-PanTumor02 (DP-02) interim results.

LBA3000 Background: T-DXd is an antibody drug conjugate targeting HER2 and is approved in HER2-expressing breast (BC) and gastric (GC) cancers. HER2 expression is prevalent in other solid tumors. The efficacy of current treatments (Tx) in these populations, including studies with HER2-directed Tx, is modest, revealing a significant unmet medical need. Clinically meaningful activity of T-DXd was seen in HER2-expressing tumors in a phase 1 study (NCT02564900). Methods: DP-02 (NCT04482309) is an open-label phase 2 study of T-DXd 5.4 mg/kg q3w in pts with HER2-expressing (immunohistochemistry [IHC] 3+ or IHC 2+ by local or central testing) locally advanced or metastatic disease that progressed after ≥1 systemic Tx or that has no Tx options. Cohorts with biliary tract (BTC), bladder (URO), cervical (CC), endometrial (EC), ovarian (OC), pancreatic (PC), or other tumors (excluding BC, GC, colorectal cancer, and non-small cell lung cancer) were enrolled. Efficacy and safety were analyzed in all pts who received ≥1 dose of T-DXd. The primary endpoint was investigator-assessed confirmed objective response rate (ORR). Secondary endpoints included duration of response (DOR), disease control rate, progression-free and overall survival, and safety. Results: At data cutoff (16 Nov 2022; median follow-up, 9.7 mo), 267 pts had been treated (median, 2 prior lines of Tx [range, 0-13]); 75 pts were IHC 3+ and 125 were IHC 2+ by central testing. In all 267 pts, the ORR was 37.1% and median DOR (mDOR) was 11.8 mo; in pts with IHC 3+ expression, the ORR was 61.3% and mDOR was 22.1 mo. ORR per cohort is shown in all pts and those with centrally confirmed HER2 IHC 3+ or IHC 2+ expression. Grade (G) ≥3 adverse events (AEs) occurred in 58.4% of pts; 11.6% discontinued Tx due to AEs. Adjudicated drug-related interstitial lung disease/pneumonitis occurred in 18 pts (6.7% [G1, n=6; G2, n=11; G5, n=1]). Conclusions: This is the first tumor-agnostic global study of T-DXd in a broad range of HER2-expressing solid tumors. T-DXd showed encouraging ORR, particularly in pts with IHC 3+ expression, durable clinical benefit, and a manageable safety profile in this heavily pretreated population. These interim results show T-DXd to be a potential new Tx option for pts with HER2-expressing solid tumors. Clinical trial information: NCT04482309 . [Table: see text]

A phase 1, first-in-human, open label, escalation and expansion study of ORM-5029, a highly potent GSPT1 degrader targeting HER2, in patients with HER2-expressing advanced solid tumors.

TPS1114 Background: Targeted protein degradation (TPD) molecules have expanded the therapeutic options through their catalytic mechanism of action (MOA) and ability to degrade “undruggable” proteins. To increase the efficacy versus tolerability window of protein degradation and improve drug delivery, ORM-5029 uses a Dual-Precision TPD (TPD2) approach combining the catalytic mechanism of TPDs with the precision of tumor-targeting therapeutic antibodies. ORM-5029 is a first-in-class human epidermal growth factor receptor 2 (HER2)-targeted antibody-drug conjugate (ADC) comprised of SMol006, a highly potent GSPT1 degrader, conjugated to pertuzumab, a clinically validated antibody. HER2 is overexpressed in cancers such as breast, ovarian and gastric, and associated with early-onset aggressive disease. ORM-5029 is in development for treatment of HER2-expressing solid tumors. The MOA is mediated by targeted uptake of the ADC, release of the TPD payload, and cell death by GSPT1 degradation. ORM-5029 showed robust in vitro and in vivo efficacy in multiple HER2-expressing models with comparable activity to trastuzumab deruxtecan and strong activity in trastuzumab emtansine-refractory models. Methods: This phase 1 first-in-human study evaluates the safety, tolerability, and efficacy of ORM-5029 administered by intravenous infusion in patients (pts) with HER2-expressing advanced solid tumors (NCT05511844). The escalation, guided by the Bayesian Optimal Interval design, explores cohorts of ORM-5029 to identify the maximum tolerated dose (MTD) and/or expansion dose level (EDL). Each cohort will enroll ≥3 breast cancer pts with at least HER2 1+ (HER2 low) or greater by immunohistochemistry or positive by in situ hybridization. Expansion cohort A (HER2+ breast cancer) may enroll in parallel to escalation evaluating doses showing pharmacodynamic activity or efficacy. Up to 10 pts may be enrolled at each dose explored in cohort A. Enrollment into expansion cohort B (up to 21 pts) and cohort C (up to 22 pts) will begin once the EDL has been determined to further assess the safety, tolerability and efficacy of ORM-5029 using a Simon’s optimal 2-stage design. Cohort B will enroll pts with HER2+ breast cancer refractory or intolerant to standard treatment after ≥2 HER2 therapies in the metastatic setting. Cohort C will enroll pts with advanced solid tumors that are refractory or intolerable to standard treatment or for which no standard treatment is available, including HER2+ gastric or gastroesophageal junction adenocarcinoma or tumors with HER2 expression, amplification or mutations (e.g., colorectal, bile duct, ovarian, bladder, non-small cell lung). Study enrollment began in October 2022 in the United States. Escalation cohort 1 was completed without DLT; enrollment in cohort 2 began as of December 2022. Clinical trial information: NCT05511844 .

A phase 1/2 study of a first-in-human immune-stimulating antibody conjugate (ISAC) BDC-1001 in patients with advanced HER2-expressing solid tumors.

2538 Background: BDC-1001 is a HER2-targeted immune-stimulating antibody conjugate (ISAC), designed to trigger local activation of the innate immune system and generate a durable tumor-targeted adaptive immune response. BDC-1001 incorporates a trastuzumab biosimilar (EG12014) conjugated to a proprietary TLR7/8 agonist using a non-cleavable linker and a cell membrane-impermeable payload. An international phase 1/2 study was initiated to evaluate the safety of BDC-1001 ± nivolumab (nivo) and to identify the recommended phase 2 dose (RP2D) considering PK/PD analyses and preliminary efficacy. Methods: Dose-escalation (3+3, +backfills) enrolled patients (pts) with HER2-positive (amplified, or IHC 3+) or HER2 low (IHC 2+ and not amplified) solid tumors who had progressed after standard therapies. BDC-1001 was given IV q3w, q2w, or q1w as monotherapy (mono; n=91) and q2w or q1w with nivo 240 mg q2w (combo; n=27). Results: As of Nov 23, 2022, 118 pts with 16 different tumor types, were enrolled with BDC-1001 doses ranging from 0.15 to 20 mg/kg. Mean age was 61 yrs with a median of 4 and 5 prior lines of therapy (range, 1-11; 1-14; prior anti-HER2 therapy (HER2Tx) [66%/70%], immunotherapy (IO) [23%/22%]) for mono and combo, respectively. Median follow-up time was 5.0-6.1 months. Treatment was well tolerated with only 1 DLT (Gr3 supraventricular tachycardia) at 8 mg/kg q1w combo cohort. Low-grade IRRs were the most common related TEAEs (mono, 26.5%; combo, 25.9%). A related SAE (Gr4, bronchopulmonary hemorrhage) was seen in 1 pt (mono, 1.1%). Antitumor activity was observed at a range of doses and malignancies. There were 4 confirmed (RECIST 1.1) durable PRs (all in MSS tumors with low/intermediate TMB, prior Tx: 1 HER2Tx, 1 IO) including 1 pt with colon cancer (CRC) in the 5 mg/kg q3w mono cohort, and 3 in the 20 mg/kg q2w cohorts (mono 1/7; combo 2/7; ovarian, biliary, and rectal cancers). After the data cut, an additional PR (unconfirmed) was reported at week 6 in a pt with CRC receiving 12m/kg 1qw combo. Ten additional pts had SD lasting ≥6 months (8 mono; 2 combo; prior Tx: 6 HER2Tx; 1 IO; e.g., ovarian, endometrial, colorectal, gastric). Durable SDs were most frequent in the q2w cohorts. BDC-1001 exposure (e.g., Cmin) correlated with activity among pts in q2w cohorts. Increases in myeloid and T cell infiltration markers in post-Tx tumor biopsies align with mechanism of action (MoA). No anti-drug antibodies were detected. Conclusions: BDC-1001 mono and combo were well-tolerated. Targeted serum exposure levels were achieved, and encouraging clinical activity was noted in heavily pretreated pts with various HER2 positive tumors, especially in the 20 mg/kg q2w cohorts. Immune biomarker changes from plasma and tumor were consistent with MoA of this ISAC. These data support further development of BDC-1001 with phase 2 expansion in HER2-expressing solid tumors at the RP2D. Clinical trial information: NCT04278144 .

A first-in-human, open label, multiple dose, dose escalation, and cohort expansion phase I study to investigate the safety, tolerability, pharmacokinetics and antitumor activity of BB-1701 in patients with locally advanced/metastatic HER2-expressing solid tumors.

3029 Background: BB-1701 is an antibody-drug conjugate consisting of a humanized IgG1κ monoclonal antibody and eribulin. When BB-1701 targets HER2-expressing cancer cells and is internalized, free eribulin is cleaved from the ADC by cathepsin b and causes cytotoxicity to cancer cells. The neighboring cells were affected with bystander effects, like cytotoxicity on tumor cells and non-cytotoxic effects on microenvironment by free eribulin. Here, we report preliminary results from this phase 1 study (NCT04257110). Methods: This dose escalation study followed an accelerated titration and traditional "3 + 3" design with 6 dose levels from 0.4 to 2.6 mg/kg Q3W. Patients with confirmed advanced/metastatic HER2 overexpressing solid tumors, who had progressed on, or were intolerant to prior standard therapies, aged ≥ 18 years, with ECOG PS ≤ 2, and measurable disease, were enrolled. HER2 expressions were determined by IHC or next generation sequencing. Tumor imaging was conducted every 9 weeks. The primary objective is the assessment of safety and tolerability, and the secondary objective is the assessment of PK and preliminary anti-tumor activity. Results: A total of 29 patients were enrolled in this study. Tumor types were breast cancer, gastric/gastroesophageal junction cancer, colorectal cancer, gallbladder cancer, ovarian cancer and urothelial cancer. The medium prior lines of systemic therapy were 3 (range 1 – 6). During this study, no DLT was observed and the MTD was not reached. The most commonly reported (≥20%) treatment-related adverse events (TRAEs) were peripheral neuropathy, aspartate aminotransferase increased, neutrophil count decreased, white blood cell count decreased, alanine aminotransferase increased, hypertriglyceridemia, anemia, platelet count decreased. The most commonly reported ≥ grade 3 TRAEs (≥10 %) was peripheral neuropathy. There were two grade 4 adverse events: neurological symptom and sepsis. There was no interstitial lung disease observed during the study. Nine patients discontinued the study treatment due to peripheral neuropathy. Thirteen patients out of 26 patients evaluable for antitumor activity achieved partial response (PR), and 11 patients had stable diseases (SD). The best overall response rate (BOR) was 50.0% (13/26) and the disease control rate (DCR) was 92.3% (24/26). For 17 breast cancer patients in the study, 12 patients achieved PR, and 5 patients had SD. The BOR was 70.5% (12/17) and the DCR was 100% (17/17). For 5 gastric cancer patients in the study, all patients had SD. The duration of treatment ranged from 2 weeks to 66 weeks. Conclusions: BB-1701 was generally well tolerated up to 2.6 mg/kg dose levels and has shown promising antitumor activity in patients with HER2-overexpression solid tumors. Clinical trial information: NCT04257110 .