Efficacy and Safety of Trastuzumab Deruxtecan in Patients With HER2-Expressing Solid Tumors: Primary Results From the DESTINY-PanTumor02 Phase II Trial.

Purpose: Trastuzumab deruxtecan (T-DXd) is a human epidermal growth factor 2 (HER2)-directed antibody-drug conjugate approved in HER2-expressing breast and gastric cancers and HER2-mutant non-small-cell lung cancer. Treatments are limited for other HER2-expressing solid tumors. Methods: This open-label phase II study evaluated T-DXd (5.4 mg/kg once every 3 weeks) for HER2-expressing (immunohistochemistry [IHC] 3+/2+ by local or central testing) locally advanced or metastatic disease after ≥1 systemic treatment or without alternative treatments. The primary end point was investigator-assessed confirmed objective response rate (ORR). Secondary end points included safety, duration of response, progression-free survival (PFS), and overall survival (OS). Results: At primary analysis, 267 patients received treatment across seven tumor cohorts: endometrial, cervical, ovarian, bladder, biliary tract, pancreatic, and other. The median follow-up was 12.75 months. In all patients, the ORR was 37.1% (n = 99; [95% CI, 31.3 to 43.2]), with responses in all cohorts; the median DOR was 11.3 months (95% CI, 9.6 to 17.8); the median PFS was 6.9 months (95% CI, 5.6 to 8.0); and the median OS was 13.4 months (95% CI, 11.9 to 15.5). In patients with central HER2 IHC 3+ expression (n = 75), the ORR was 61.3% (95% CI, 49.4 to 72.4), the median DOR was 22.1 months (95% CI, 9.6 to not reached), the median PFS was 11.9 months (95% CI, 8.2 to 13.0), and the median OS was 21.1 months (95% CI, 15.3 to 29.6). Grade ≥3 drug-related adverse events were observed in 40.8% of patients; 10.5% experienced adjudicated drug-related interstitial lung disease (ILD), with three deaths. Conclusion: Our study demonstrates durable clinical benefit, meaningful survival outcomes, and safety consistent with the known profile (including ILD) in pretreated patients with HER2-expressing tumors receiving T-DXd. Greatest benefit was observed for the IHC 3+ population. These data support the potential role of T-DXd as a tumor-agnostic therapy for patients with HER2-expressing solid tumors. Trial registration: ClinicalTrials.gov NCT04482309.

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]

IntroductionDESTINY-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.MethodsThis phase 2, open-label study evaluated T-DXd (5.4 mg/kg once every 3 weeks) 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.ResultsIn 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 14.2 months (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 9.8 months (95% CI 4.5, 12.6). Safety was consistent with the known profile of T-DXd.ConclusionIn 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.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12325-024-02975-x.

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.

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.

Linvoseltamab in Patients with Relapsed/Refractory Multiple Myeloma: Longer Follow-up and Selected High-Risk Subgroup Analyses of the Linker-MM1 Study

IntroductionTrastuzumab deruxtecan (T-DXd) has demonstrated significant survival benefit for patients with HER2-expressing breast and gastric cancers. In DESTINY-PanTumor02, T-DXd demonstrated clinically meaningful response rates, progression-free survival (PFS), and overall survival...

Background: T-DXd is a HER2-directed antibody-drug conjugate that is approved in multiple countries for the treatment of HER2-positive and HER2-low breast cancer, HER2-positive gastric or gastroesophageal junction adenocarcinoma, and HER2-mutant non-small cell lung cancer (NSCLC). In April 2024, T-DXd received accelerated approval in the US for adult pts with unresectable or metastatic HER2-positive (immunohistochemistry [IHC] 3+) solid tumors that have progressed after prior systemic treatment and have no satisfactory alternative therapies. In Part 1 of the DP-02 study (N=267), T-DXd showed clinically meaningful investigator-assessed (INV) objective response rates (ORRs; 37.1% [95% CI 31.3, 43.2]) and INV median progression-free survival (PFS; 6.9 months [95% CI 5.6, 8.0]) in pretreated pts with HER2-expressing solid tumors, with the largest effect observed in pts with centrally confirmed HER2 IHC 3+ tumors (ORR 61.3% [95% CI 49.4, 72.4]; median PFS 11.9 months [95% CI 8.2, 13.0]); safety was consistent with the known profile. Here, we describe Part 2 of the DP-02 study. Methods: DP-02 (NCT04482309) is an open-label, multicenter, Phase 2 study evaluating T-DXd (5.4 mg/kg intravenously once every 3 weeks) in pts with HER2-expressing locally advanced or metastatic solid tumors that have progressed following prior systemic treatment or have no alternative treatment options. Part 2 will enroll ∼40 pts in each of the following cohorts: A, any HER2 IHC 3+ tumor; B, any HER2 IHC 2+ / in situ hybridization-positive tumor; C, HER2 IHC 2+/1+ endometrial cancer; D, HER2 IHC 2+/1+ ovarian cancer; or E, HER2 IHC 2+/1+ cervical cancer. Pts with breast, gastric, or colorectal cancer will not be enrolled; unlike in Part 1, pts with NSCLC will be eligible for cohorts A and B. HER2 expression will be determined by central testing and scored per ASCO/CAP gastric-specific criteria. The primary endpoint is INV confirmed ORR per RECIST 1.1. Secondary endpoints include duration of response, disease control rate, PFS, and overall survival. Safety, tolerability, pharmacokinetics, and immunogenicity will also be assessed. Previously presented at ESMO Asia 2024; Final Publication Number: 400 TiP; Jung-Yun Lee et al. Reused with permission Citation Format: Funda Meric-Bernstam, Jung-Yun Lee, Vicky Makker, Ana Oaknin, Chiedozie Anoka, Lindsey Jung, Soham Puvvada, João Simões, Do Youn Oh. An open-label, multicenter, phase 2 study of trastuzumab deruxtecan (T-DXd) in patients (pts) with HER2-expressing solid tumors: DESTINY-PanTumor02 (DP-02) Part 2 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_2):Abstract nr CT249.

Brief Report: First-line Pembrolizumab in Metastatic Non-Small Cell Lung Cancer Habouring MET Exon 14 Skipping Mutation and PD-L1 ≥50% (GFPC 01-20 Study)

Trastuzumab deruxtecan in previously treated patients with HER2-positive metastatic breast cancer: updated survival results from a phase II trial (DESTINY-Breast01)

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]

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.

Summary of the original article, ‘Efficacy of Trastuzumab Deruxtecan in HER2-Expressing Solid Tumors by Enrollment HER2 IHC Status: Post Hoc Analysis of DESTINY-PanTumor02’. Trastuzumab deruxtecan (T-DXd) is an antibody-drug conjugate, which is a chemotherapy with a linker (deruxtecan) joined to an antibody (trastuzumab). Trastuzumab binds to the human epidermal growth factor receptor 2 (HER2) protein on cancer cells, where it releases the chemotherapy to kill these cells. The DESTINY-PanTumor02 clinical study tested the effectiveness of T-DXd for people with various HER2-expressing cancers and the safety of treatment. Previous results from DESTINY-PanTumor02 showed that T-DXd had antitumor activity, and the greatest effects were seen in people with the highest tumor level of HER2 [defined as immunohistochemistry (IHC) 3+]. In this previous analysis, the HER2 expression was measured at a central laboratory. In clinical practice, HER2 expression will likely be measured at a local laboratory, so understanding whether T-DXd has similar effects regardless of how HER2 expression is measured is important. Here, we looked at the effects of T-DXd based on the HER2 test result used to determine a person’s eligibility for the study, which could be measured using a local or central laboratory. In people with IHC 3+ tumors (where HER2 was measured at a local or central laboratory), 51% had a decrease in the size or number of tumors, according to established criteria (referred to as an objective response), while, in people with IHC 2+ tumors, 26% had an objective response. Side effects with T-DXd were consistent with previous studies. These results confirm T-DXd has antitumor effects in HER2-expressing cancers where the HER2 expression is measured by a local or central laboratory.

IntroductionThis study aims to investigate the effectiveness and safety of combining the antibody-drug conjugate (ADC) disitamab vedotin (RC48) with the established PRaG regimen (PD-1 inhibitor, Radiotherapy, and GM-CSF) for treating HER2-expressing (IHC 3+, 2+, or 1+) advanced solid tumors. This novel PRaG3.0 regimen is hypothesized to leverage the tumor radiosensitizing and immunogenic cell death properties of ADCs to amplify the synergistic antitumor effects of radioimmunotherapy, offering a potential paradigm for pan-cancer therapy.MethodsThis study is a prospective, single-arm, open-label, multi-center clinical trial. Patients enrolled have confirmed HER2-expressing solid tumors (IHC 3+, 2+, or 1+) that have progressed after standard treatment or were intolerant to it. Patients received RC48 (2 mg/kg) via intravenous injection on day 1, followed by subcutaneous GM-CSF at 200 µg from days 3 to 7 and interleukin-2 (IL-2) at 2 million IU from days 8 to 12. Radiotherapy was initiated on day 3, targeting one lesion with hypofractionated radiotherapy (2-3 fractions of 5 or 8 Gy). PD-1/PD-L1 antibodies were administered within one week after completing radiotherapy. Treatment was repeated every three weeks, and if there were no target lesions, radiotherapy could be discontinued, with RC48 given for at least six cycles. After achieving a complete tumor response, maintenance therapy with PD-1/PD-L1 antibodies continued until disease progression or intolerable toxicity occurred. The primary endpoint was the objective response rate (ORR).ResultsThe study is currently in the recruitment phase (Registration No: NCT05115500). The primary endpoint is the objective response rate (ORR). Secondary endpoints include progression-free survival (PFS), overall survival (OS), disease control rate (DCR), safety, and QoL. Planned enrollment is 62 patients.ConclusionThe PRaG3.0 protocol represents an innovative approach combining ADC therapy with radioimmunotherapy to address HER2-expressing cancers, including those with HER2-low expression. If successful, this regimen could establish a highly effective combination strategy.

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.