Dose-limiting Toxicity Research Articles

A phase I clinical study to evaluate the safety, tolerability, immunogenicity, pharmacokinetics and preliminary efficacy of SCB-219M in patients with chemotherapy-induced thrombocytopenia (CIT): An interim analysis.

e15015 Background: CIT is a serious, chemotherapy-associated complication observed in a wide range of cancer patients with various types of cancer. Incidence of CIT can occur in about 15-25% of patients undergoing standard chemotherapy regiments with platinum, taxane and/or gemcitabine-based regimen. CIT can lead to chemotherapy dose delay or dose reduction, and potentially bleeding events. Currently, there is no FDA-approved therapy for CIT. SCB-219M, a thrombopoietin receptor agonist (TPO-RA) mimetic bispecific Fc-fusion protein produced from CHO cells can efficiently raise PLT count under normal and pathological conditions in laboratory animals. Methods: This is a single-arm, multi-center, open-label, dose escalation Phase Ia clinical study to evaluate the safety, tolerability, and immunogenicity, PK profile and preliminary efficacy of a single ascending dose of SCB-219M administered one day after a chemotherapy in prior CIT patients with malignant solid tumors and lymphoma. The study design of accelerated titration combined with "3 + 3" is used, and the number of subjects planned to enroll is 12 to be assigned to 4 cohorts with 2, 6, 10 and 15 mg/kg subcu administration of SCB-219M, respectively. Enrollment criteria include episode of CIT experienced (<75 × 109/L in PLT count) in prior cycle of chemotherapies and PLT count has recovered to >75 × 109/L prior to initiation of this study . The chemotherapy regimen allowed include either mono or combination chemotherapy (including targeted therapy and/or immunotherapy). The observation period of dose-limiting toxicities (DLTs) is 21 days. Chemotherapy is planned at each study site. There will be no change in the planned dose or frequency of chemotherapy in the study. Results: As of Dec 20, 2023, 9 prior CIT patients including 3 at 15 mg/kg were enrolled. SCB-219M was well tolerated. There were no SAEs or AESIs (Adverse Event of Special Interest) observed. DLT was not reached. A favorable PK profile, in particular in serum availability (AUC) and half-life (T1/2) was obtained. All 9 prior CIT patients in the study maintained PLT counts >75 x 109/L from 1-week following chemotherapies with a single dose of SCB-219M, and durable responses experienced through at least 3 weeks. Conclusions: In this interim analysis, drug safety, PK profile and durable efficacy are expected to support SCB-219M dosing interval of ≥2-weeks or a single dosing regimen within a chemotherapy cycle. Accordingly, a Phase Ib trial evaluating repeated dosing of SCB-219M is planned to initiate in 2024. Clinical trial information: NCT05426369 .

A phase 1, open-label, dose escalation study on the safety and tolerability of ANK-101 in advanced solid tumors.

TPS2689 Background: IL-12 is a cytokine that can stimulate both innate and adaptive tumor immunity. Clinical trials of intravenous IL-12 demonstrated anti-tumor activity limited by significant systemic toxicity, including patient deaths. ANK-101 is an anchored immunotherapy that links IL-12 to aluminum hydroxide through an alum-binding protein (ABP). The ANK-101 complex anchors IL-12 in the tumor microenvironment (TME), resulting in prolonged local retention and low levels of systemic absorption. Preclinical studies in murine tumor models showed that ANK-101 is retained at the injection site for up to 28 days, recruits and activates T and NK cells, promotes M1 myeloid cell differentiation, induces regression of both injected and un-injected tumors, and induces immunologic memory. Methods: This is a first-in-human, open-label dose escalation study of ANK-101 in advanced solid tumors with a planned sample size of 12-36 participants. The first three dose escalation cohorts include a single participant, and then study enrollment follows a standard 3+3 dose escalation design. If no dose limiting toxicity (DLT) is observed, the dose level will be escalated until ≥1/3 or ≥2/6 patients experience a DLT. An additional ten patients will be enrolled at the recommended dose for expansion (RDE). Participants will be treated with intratumoral ANK-101 every 3 weeks for 4 cycles. Imaging or clinical assessments will be performed at week 12. If there is no significant clinical deterioration or unacceptable toxicity at this visit, participants may receive four more cycles. Eligible patients must have an advanced solid malignancy refractory to standard treatment and be accessible for injection and biopsy, measurable disease by RECIST v1.1, and ECOG PS of 0-1. Key exclusion criteria include tumors close to vital structures, uncontrolled bleeding disorders, and active autoimmune disease. Primary objectives of the study are to determine the safety and tolerability of ANK-101 and identify the RDE. Secondary objectives include pharmacokinetics (PK) and immunogenicity (ADA) of ANK-101 and clinical activity as measured by ORR, DCR, DOR and PFS by RECIST v1.1. Exploratory objectives include assessment of QOL using FACT-G and profiling immune-based pharmacodynamic (PD) changes. PD assessments will include serum cytokines and circulating immune cells, and local levels of PD-L1, CD8+ T cells, and CD68+ macrophages, and changes in gene expression within the TME. This clinical trial is in progress. Clinical trial information: NCT06171750 .

Open-label, phase 1, multicenter study to evaluate the safety and preliminary anti-tumor activity of NT-175 in human leukocyte antigen-a*02:01-positive adult subjects with unresectable, advanced and/or metastatic solid tumors that are positive for the TP53 R175H mutation.

e14514 Background: The TP53 tumor suppressor gene is the most commonly mutated gene across all cancer types, and TP53 R175H is the most common recurrent mutation across indications, identified in 6.7% of patients with breast cancer, 6% of patients withs colorectal cancer, and 4.2% of patients with pancreatic cancer. No therapy is approved for treatment directly targeting TP53 R175H. NT-175 is an armored autologous T-cell product expressing an HLA-A*02:01-restricted TCR recognizing TP53 R175H with disruption of the endogenous TCR and the transforming growth factor beta receptor type 2 (TGFBR2) genes. Methods: This first-in-human phase I, open label study will assess the safety and preliminary anti-tumor activity, identify the maximum tolerated dose (MTD), and evaluate the persistence, and functional capacity of NT-175 in subjects with advanced, recurrent unresectable/metastatic solid tumors refractory to treatment options. The study will enroll approximately 24 subjects harboring TP53 R175H and HLA-A*02:01. Enrolled patients will undergo leukapheresis from which CD4 and CD8 T cells will be enriched and activated ex vivo. The endogenous TCR α and β chain gene are knocked out utilizing clustered Regularly Interspaced Short Palindromic repeats (CRISPR-Cas9) and the TCR encoding an HLA-A*02:01-restricted TCR specific to the TP53 R175H mutation is inserted in the TCR α locus. Additionally, the T cells are edited to disrupt the gene encoding the TGFBR2 to reduce the immunosuppressive effect of TGF-β in the tumor microenvironment. Subjects will undergo lymphodepletion chemotherapy with fludarabine and cyclophosphamide followed by a single infusion of NT-175 and subcutaneous recombinant IL-2 administration for up to 8 days. Dose escalation will occur across 3 ascending dose levels following the BOIN design. Subjects will be monitored for dose-limiting toxicities for 28 days after NT-175 infusion. Tumor response will be assessed by RECISTv1.1 criteria. All subjects will be followed for up to 15 years. Primary endpoints include safety, dose limited toxicities, MTD determination, and recommended Phase II dose. Secondary endpoints include preliminary efficacy measures. Translational analysis will evaluate potential biomarkers for insights into mechanism of action, response prediction, or resistance mechanisms. The study was activated in March 2023 and is open to accrual; 5 patients have been enrolled as of 4 Jan 2024.

QUIC: Phase 2 study of gemcitabine, cisplatin, quemliclustat (AB680), and zimberelimab (AB122) during first-line treatment of advanced biliary tract cancers (BTC)—Big Ten Cancer Research Consortium study BTCRC-GI22-564.

TPS4195 Background: Despite recent approvals of immune checkpoint inhibitors with chemotherapy in the first-line setting, the median overall survival (mOS) for patients with advanced biliary tract cancer (BTC) remains less than 15 months. CD73 is a key enzyme responsible for the conversion of extracellular adenosine 5’-monophosphate into adenosine and may play an important role in creating an immunosuppressed tumor microenvironment. High expression of CD73 in BTC is associated with decreased OS. Quemliclustat (Q) is a potent, selective, reversible inhibitor of CD73. Q in combination with chemotherapy has demonstrated promising activity in patients with advanced pancreatic cancer without significant increase in adverse events. The BTCRC-GI22-564 study evaluates safety and preliminary efficacy of Q in combination with zimberelimab (Z), a monoclonal antibody targeting human PD-1, with gemcitabine and cisplatin (GC) as first-line therapy for patients with advanced BTC, QUIC (Q and Immunotherapy in Cholangiocarcinoma). Methods: This is an open label, single arm, phase II multi-site trial, evaluating Q and Z in combination with GC in patients with advanced BTC who have not received systemic treatment for advanced disease or who completed adjuvant therapy > 6 months prior to development of recurrent disease. Chemotherapy is given on days 1, 8, 22 and 29 of each 42-day cycle as per local standards. Z is administered at a fixed dose of 360 mg via IV infusion every 3 weeks. Q is administered via IV infusion on days 1, 15, and 29. A safety run-in portion built into the study is planned to enroll 6 subjects to ensure there are no dose limiting toxicities (DLT). If a study defined DLT is observed, Q, gemcitabine and cisplatin will be reduced by 1 dose level, and an additional 6 subjects will be enrolled in the safety run-in portion. The primary efficacy endpoint is median progression free survival (mPFS) with null and alternative survival of 6.0 and 10.0 months, respectively. Based on an accrual rate of 3 patients per month, we expect to accrue 33-39 patients which will provide at least 83% power with a one-sided alpha of 0.1. Secondary endpoints include mOS, disease control rate, overall response rate, and duration of response. Correlative endpoints will assess clinical outcomes with immune infiltration within tumor microenvironment, CD73 and PD-L1 expression. The QUIC study is currently open to enrollment through BTCRC. Clinical trial information: NCT06048133 .

Safety and efficacy of selpercatinib in pediatric patients with RET-altered solid tumors: Updated results from LIBRETTO-121.

10022 Background: Selpercatinib is a highly selective and potent CNS-penetrant oral RET inhibitor, approved for treatment of RET-driven thyroid cancer in adult and adolescent patients (pts), and lung or other solid tumors in adult pts. Here we present updated results from LIBRETTO-121, the first trial to assess the safety and efficacy of a selective RET inhibitor in pediatric and adolescent pts with RET-altered solid tumors. Methods: LIBRETTO-121 (NCT03899792) is a multicenter phase 1/2 trial in pts 0.5-21 yrs of age with advanced, RET-altered solid tumors. Enrollment began in June 2019 and is ongoing. To confirm the recommended phase 2 dose for selpercatinib, dosing started at 92 mg/m2 BID, expecting to result in equivalent exposure to 160 mg BID in adults.The primary objectives were to evaluate safety and dose limiting toxicities (DLTs) in phase 1 and determine the ORR per RECIST 1.1 by independent review in the phase 2 population. Results: At the data cut-off (January 13, 2023), 27 pts aged 2-20 yrs were treated with selpercatinib. Tumor types included RET-mutant medullary thyroid cancer (MTC, n = 14), RET fusion-positive papillary thyroid cancer (PTC, n = 10), or other (n = 3). The most common RET alterations were a M918T mutation (71.4% [10/14] of MTC pts) or NCOA4-RET fusion (50% [5/10] of PTC pts). Pediatric and adolescent patients treated at 92 mg/m2 (up to 160 mg BID) had a similar exposure as adults treated with 160 mg BID at steady state on cycle 1 day 8. Time on selpercatinib ranged from 0.4 to 40.8 mo and 22 pts remain on treatment. There were no treatment discontinuations due to DLTs or TEAEs; 2 pts (7.4%) experienced a dose reduction due to TEAEs (elevated ALT and reduced neutrophil count). The most common TEAEs observed (≥25% of pts) were diarrhea, headache, coronavirus infection, nausea, vomiting, elevated ALT, elevated AST and pyrexia. The most common TEAEs ≥ G3 included constipation, reduced neutrophil count, vomiting and weight gain, each occurring in 2 pts (7.4%). One pt (age 15 yrs) experienced a TEAE ≥ G3 of epiphysiolysis, a risk for selpercatinib in this population based on pre-clinical data. In pts with RECIST measurable disease at baseline, the ORR was 83.3% (10/12), while 1 pt had stable disease (SD) and 1 pt had progressive disease (PD). Among pts with measurable disease at baseline, PTC pts had an ORR of 100% (5/5), and MTC pts had an ORR of 83.3% (5/6), while 1 MTC pt had SD. No PTC or MTC pts had PD. Responses were durable, with a 24 mo DOR rate of 100% (95% CI: NE, NE). With a median follow up of 18 mo, the mPFS among all pts has not yet been reached, and the 24 mo rate of PFS was 92.4% (95% CI: 73.0% - 98.1%). Conclusions: Selpercatinib’s safety profile remains consistent with prior reports from adult trials. These results, including more robust efficacy and PK data, continue to support the use of selpercatinib in pediatric and adolescent pts with RET-altered solid tumors. Clinical trial information: NCT03899792 .

A phase I/II open-label clinical trial of CPI-613 in combination with modified FOLFIRINOX in patients with locally advanced (LAPC) or borderline resectable pancreatic cancer (BRPC).

4172 Background: Pancreatic ductal adenocarcinoma (PDA) carries a poor prognosis with a 5-year relative survival rate of 13%. Surgical resection is the only curative treatment option, but less than 20% of patients are eligible at diagnosis. A subset of patients with locally advanced disease can become candidates for resection with neoadjuvant (NA) therapy. mFOLFIRINOX is the standard of care in the adjuvant setting, with extrapolated data supporting its use in the NA setting. CPI-613/Devimistat (D) is a small molecule that targets mitochondrial metabolism in tumor cells leading to ROS-mediated apoptosis. A phase III trial of mFOLFIRINOX + D at 500 mg/m2 in metastatic PDA did not meet primary endpoint of overall survival (OS). Here we present the results of the combination’s use at standard and escalated doses in LAPC and BRPC. Methods: In this investigator-initiated, single-center, phase I/II, open-label trial treatment-naïve patients with investigator assessed LAPC or BRPC were treated with mFOLFIRINOX in 14 day cycles + D. In the standard dosing (SD) cohort, patients received D at 500mg/m2 while in the dose escalation (DE) cohort; D at 750 mg/m2 or 1000 mg/m2 was used. Radiographic response was assessed every 8 weeks. Patients who remained unresectable after 12 cycles could receive additional standard treatments, including chemoradiotherapy. The primary endpoint was median overall survival (mOS), with the study powered to show a mOS improvement from the historical standard of 14 months to 28 months with mFOLFIRINOX + D. Secondary endpoints were median progression free survival (mPFS), percent resected, and safety outcomes. NCT03699319 Results: Between Dec 2018 and Mar 2022, 37 patients and 11 patients enrolled in the SD and DE cohorts. Median age 69 years (range 47-78), male/female (27/21), Caucasian (83%), LAPC/BRPC (34/14). One patient (2%) withdrew, 4 patients (8%) discontinued treatment due to toxicity, 9 patients (19%) had progressive disease prior to completion of 12 cycles. In all patients mOS was 16.3 months and mPFS was 10.7 months. By cohort: SD/DE mOS: 16.2/17.6 months (p=0.56). Fourteen patients (29%) had partial response by RECIST 1.1. Twenty patients (41.7%) had resection; mOS 29.7 months. In the SD cohort, 78% and 24% of patients had grade 3 and/or 4 AEs. There were no dose limiting toxicities (DLT) in the DE cohort, and eight patients received the maximum dose of 1000 mg/m2 of D. After the DLT period, 100% patients in DE cohort had grade 3 toxicity and 55% had grade 4 toxicity. For all the most common toxicities (gr3,4) were neutropenia (27%,25%), diarrhea (25%,0), anorexia wt. loss (23%,0), nausea/vomiting (23%,0). Conclusions: The combination of mFOLFIRINOX and D is feasible in the LAPC/BRPC population at increased dose levels of D; however, it did not meet the primary endpoint of doubling OS compared to historical controls. Clinical trial information: NCT03699319 .

ADPORT-601: First-in-human study of adenosine 2A (A2A) and adenosine 2B (A2B) receptor antagonists in patients with select advanced solid tumors.

e14681 Background: Hypoxic tumors possess high levels of extracellular adenosine within the tumor microenvironment (TME) which suppresses both innate and adaptive immune responses by binding the adenosine receptors A2AR and A2BR. TT-10 (PORT-6) and TT-4 (PORT-7) are potent and selective antagonists of A2AR and A2BR, respectively. Both agents have shown monotherapy activity in both non-immunogenic (4T-1) and immunogenic (CT-26) tumor mouse models. Optimizing inhibition of A2AR and A2BR separately and in combination provides an opportunity to dissect the role of each signaling pathway within the TME. Methods: ADPORT-601 is a multi-center, open-label Phase 1 study, evaluating the safety, efficacy, PK and pharmacodynamics of PORT-6 in participants with mCRPC, RCC, or other selected solid tumors which are refractory to standard therapy. A subsequent arm will similarly test PORT-7 in participants with selected solid tumors. The Phase 1a cohorts utilize a standard 3+3 design. Phase 1b will be initiated once recommended doses have been established and will consist of monotherapy expansion cohorts for each drug, as well as both drugs combined at the optimal doses, and with other immunotherapy agents. A novel IHC-based assay will be implemented to select for patients with high A2AR expression. Metabolomic and gene expression profiling were performed on previously acquired bone biopsy and blood samples, respectively, to characterize the role of adenosine in CRPC. Results: 10 patients with mCRPC (n=6), RCC (n=3) or NSCLC (n=1) have been enrolled at escalating doses. Treatment-related AEs have been G1-2, with fatigue (29%), nausea (29%) and vomiting (14%) being the most reported. No related SAEs or dose limiting toxicities (DLTs) have been observed. Higher adenosine precursor metabolite (e.g., AMP, ADP, ATP, ADPR, inosine) levels were observed in image-guide bone metastatic lesions relative to non-tumor bearing bone controls (P<0.05; n=10/group). A2AR and A2BR mRNA levels were enriched (1.3 and 1.4 log2 fold change, p<0.05, respectively) in the plasma of mCRPC patients compared to those with localized disease. Updated safety, efficacy, PK and adenosine expression data will be reported at the meeting. Conclusions: PORT-6 is well tolerated to date. The TME within mCRPC bone metastases provides a unique target for A2AR and A2BR antagonism. Longitudinal blood and tissue samples, including bone biopsies, are being collected to enable biomarker analyses, allowing for elucidation of the relative contribution of A2AR and A2BR in suppressing anti-tumor immunity. Multi-omic translational analyses of tissue are planned to determine whether potent adenosine receptor antagonism will have an anti-tumor effect and convert the TME from immunosuppressive to proinflammatory. Clinical trial information: NCT04969315 .

Sacituzumab govitecan (SG) plus enfortumab vedotin (EV) for metastatic urothelial carcinoma (mUC) treatment-experienced (DAD) and with pembrolizumab (P) in treatment naïve UC (DAD-IO).

TPS4618 Background: In the DAD study (NCT04724018) the combination of SG+EV demonstrated favorable safety determining a maximum tolerated dose of 10 mg/kg and 1.25 mg/kg IV D1,8 every 21 days along with encouraging efficacy in treatment resistant mUC as evidenced by an objective response rate (ORR) of 70% in 23 evaluable patients. Given cumulative toxicities and efficacy across dose levels, the recommended phase 2 dose was SG 7.5 mg/kg and EV 1.25 mg/kg D1,8 of 21-day cycle. As EV+P is now a standard of care for front line urothelial carcinoma, NCT04724018 was amended to include 2 cohorts of distinct patient populations; one expanding SG+EV (DAD) and a second exploring the SG+EV+P (DAD-IO) combination. Methods: In DAD cohort, patients with mUC progressing on platinum and immunotherapy or on one line of therapy receive SG 7.5 mg/kg + EV 1.25 mg/kg intravenously (IV) on day(D)s 1 and 8 every 3 weeks (1 cycle) until progression or intolerable toxicities. In DAD-IO cohort, patients with treatment naïve mUC are given SG 7.5 mg/kg+EV 1.25 mg/kg IV D1, 8 of a 21-day cycle with P 200 mg every 3 weeks or 400 mg every 6 weeks per investigator discretion. In both cohorts, prophylactic granulocyte colony stimulating factor (GCSF) support is given per supportive care guidelines with cycle 1. Following first dose on trial, SG and EV can be reduced and held independently for toxicity with reductions of SG to 5 mg/kg, and EV to 1, 0.75 and 0.5 mg/kg. P dose reductions are not allowed but can be held as needed for immune related adverse events. Laboratory evaluation is performed on days 1 and 8 every cycle. Imaging is performed at baseline and every 6 weeks for the first 4 cycles followed by every 9 weeks thereafter. In both cohorts, the primary endpoint is RECIST 1.1 ORR with secondary endpoints being progression free survival, overall survival, and safety. DAD aims to enroll 41 eligible patients, assuming an ORR of 65% for EV+SG, to detect a 25% improvement with over 90% power at a one-sided type I error rate of 0.05 using a single-stage exact one-sample binomial design; ³ 23 responses would rule out a null of 40% ORR. DAD-IO plans to enroll 41 eligible patients, assuming an ORR of 75% for SG+EV+P to detect a 20% improvement with 90% power at a one-sided type I error rate 0.09 based on a Simon optimal two-stage design. If ³ 11 responses are observed in the first 18 patients, an additional 23 patients will be enrolled. At least 27 responses among a total of 41 will be needed to confirm its efficacy. The study includes a 12-patient safety lead in using a Bayesian toxicity monitoring. If ≤2 dose limiting toxicities (DLTs) occur in the first 6 patients, the next 6 are enrolled. The study halts if ≥5 DLTs occur among 12 evaluable patients. Clinical trial information: NCT04724018 . [Table: see text]

A phase I/II open label study to assess safety and preliminary evidence of a therapeutic effect of azeliragon in patients refractory to first-line treatment of metastatic pancreatic cancer.

TPS4212 Background: Azeliragon is an orally administered small molecule, administered once daily, that inhibits RAGE interactions with its natural ligands, including HMGB1 and S100 proteins. Azeliragon was previously under development for Alzheimer’s disease and failed to show efficacy in phase 3 trials. Clinical safety data from these trials, with over 1500 individuals dosed for periods up to 18 months, indicated that azeliragon has a high level of safety and tolerability, virtually indistinguishable from placebo. RAGE, the receptor for advanced glycation end products, is highly expressed in pancreatic ductal adenocarcinoma (PDAC). RAGE interaction with its ligands, including S100 proteins and HMGB1 released from PDAC cells, promotes PDAC invasion, metastasis, and resistance to 5 FU and Gemcitabine. PDAC-secreted S100 proteins can also stimulate fibroblasts surrounding PDAC cells since RAGE is positively expressed in fibroblasts, promoting the desmoplastic response. RAGE has also been implicated in the muscle wasting associated with cancer and with aging, as well as in neuropathic pain, suggesting a potential supportive role in PDAC treatment. Methods: This is an open label study to determine the safety and preliminary evidence of a therapeutic effect of azeliragon in patients refractory to the standard of care treatment of metastatic pancreatic cancer. Azeliragon is administered at three dose levels in a rolling dose escalation strategy with 6 patients at each dose level: 5 mg/day (level 1), 10 mg/day (level 2) and 20 mg/day (level 3). These dose levels have an initial loading dose for 6 days at 15 mg daily, 15 mg twice a day and 30 mg twice a day, respectively. The primary objective is to determine the RP2D, defined as the dose for which <33% patients experience a dose limiting toxicity (DLT) within 28 days from initiation of dosing. Secondary endpoints include disease control, overall survival, changes in pain as determined by the Brief Pain Inventory, and changes in ECOG performance status, weight, and serum albumin. The study received regulatory approval and accrual started in June 2023. Clinical trial information: NCT05766748 .

Binary oncolytic adenovirus in combination with HER2-specific autologous CAR VST for treatment of advanced HER2-positive solid tumors (VISTA).

TPS2679 Background: Urgent therapies are needed for patients with refractory Human Epidermal Growth Factor Receptor 2 (HER2) positive solid malignancies. Our group has previously shown potent antitumor effect of a binary oncolytic/helper-dependent adenovirus (CAdVEC) with dual expression of IL-12 and PD-L1 blocker. Initial preclinical and clinical studies with direct tumor injection of CAdVEC has shown it to be safe and result in increased infiltration of CD8 T cells into the tumor microenvironment, with antitumor effect on locoregional and distant metastatic sites.1 Based on these results, we describe an ongoing study with addition of HER2-specific autologous chimeric antigen receptor (CAR)-T cell therapy to CAdVEC. Methods: This is a single arm, dose escalation phase I clinical trial guided by Bayesian Optimal Interval Design (BOIN) for patients with advanced HER2 positive solid tumors. Patients who are deemed unsuitable for curative treatments and progressed after at least one standard first line therapy are eligible. HER2 positivity is determined by IHC and defined as ≥2+. Patients are required to have at least one tumor site appropriate for intratumor injection and radiographically measurable disease per RECIST v1.1. Patients with autoimmune disease requiring systemic corticosteroids greater than 10mg/day and those with active/untreated CNS metastasis are excluded. Patients will receive increasing doses of CAdVEC intratumor injection alone (first two dose levels) or in combination with HER2 specific autologous CAR-T cells (dose levels 3-7). A total of 45 patients are planned. The primary endpoint of the study is to evaluate safety and maximum tolerated dose as assessed by incidence of dose limiting toxicities (DLT) of CAdVEC intratumor injection in combination with HER2-specific autologous CAR T cells. Secondary endpoints include anti-tumor activity of the combination measured by overall response rate (ORR), disease control rate (DCR), median progression free survival (PFS) and median overall survival (OS). Exploratory endpoints include assessing the immunogenicity of combination therapy by determining the impact of treatment on cellular and humoral immunity, as well as assessing long-term persistence and functional status of HER2 CAR T-cells. Correlative analysis of levels of adenovirus antibodies with clinical outcomes and immunological findings are also planned. This study is currently enrolling. 1. Wang D, Porter CE, Lim B, et al: Science Advances 9, 2023. Clinical trial information: NCT03740256 .

A phase 1/2, first-in-human, open-label, dose-escalation study of TAK-280, an investigational B7-H3 x CD3ε conditional bispecific redirected activation (COBRA) T-cell engager, in adult patients with unresectable, locally advanced, or metastatic solid tumors.

TPS2684 Background: TAK-280 is a novel COBRA T-cell engager that targets the B7 homolog 3 protein (B7-H3), an antigen highly expressed in a range of solid tumors including metastatic castration-resistant prostate cancer (mCRPC) and non–small cell lung cancer. In its prodrug form, TAK-280 binds to B7-H3, but not to CD3ε. Once in the protease-rich tumor microenvironment, TAK-280 undergoes protease-mediated activation through formation of CD3ε-binding active dimers, which stimulate CD3 T-cell activation and cytotoxic antitumor response against co-engaged B7-H3–expressing cells. In preclinical studies, TAK-280 demonstrated cleavage-dependent conditionality, engagement of tumor target antigen, and induction of T-cell mediated tumor killing. TAK-280 has the potential to target solid tumors that are not amenable to treatment with conventional first- or second-generation T-cell engagers, while limiting toxicity to normal tissues. Methods: This phase 1/2 study is enrolling adult patients with unresectable, locally advanced, or metastatic solid tumors described in the literature to have enhanced B7-H3 expression, who are ineligible or intolerant to standard therapies. Other eligibility criteria include Eastern Cooperative Oncology Group performance status ≤1 and measurable disease per RECIST v1.1. Key exclusion criteria include history of autoimmune disease, major surgery ≤8 weeks before first dose of TAK-280, and history of clinically significant cardiac or gastrointestinal disorders. During phase 1 dose escalation, TAK-280 is administered as an intravenous infusion, once weekly, in 28-day cycles at a pre-defined dose level range. Patients who do not experience dose-limiting or other unacceptable toxicities may receive up to 14 treatment cycles depending on response; patients are treated until disease progression, unacceptable toxicity, or withdrawal from study. The dose-escalation phase will determine two recommended doses for expansion to be assessed during the cohort-expansion phase. The primary endpoint is incidence of dose-limiting or other toxicities during dose escalation; secondary endpoints include pharmacokinetic parameters, response assessment per RECIST v1.1, overall response rate, duration of response, progression-free survival, overall survival, disease control rate, and prostate-specific antigen response in patients with mCRPC. Cytokine release syndrome is closely managed and reported per American Society for Transplantation and Cellular Therapy consensus grading. Approximately 182 patients are planned to be enrolled (42 in dose escalation and 100–142 in cohort-expansion); as of the data cutoff date of Jan 10, 2024, 18 patients have received the study drug. Clinical trial information: NCT05220098 .

Safety and efficacy of first-in-class CXCR1/2 inhibitor SX-682 in combination with pembrolizumab (pem) in patients (pts) with metastatic melanoma (mMEL) with disease progression on anti–PD-1 therapy.

9508 Background: Outcomes for pts with mMEL remain sobering despite access to available immunotherapies as the majority of pts are resistant or become refractory to checkpoint blockade with no approved treatments. CXCR1 and CXCR2 (CXCR1/2) signaling mediate myeloid immunosuppression and MEL growth, inversely correlating with anti-PD-1 response and pt survival. SX-682 is an oral allosteric inhibitor of CXCR1/2. As a single agent, SX-682 increases tumor CD8+ T cell infiltration and inhibits tumor growth in mouse MEL. Methods: This phase 1 dose-escalation with expansion trial (NCT03161431) evaluated pem and escalating doses of SX-682 (25 - 400 mg orally BID) in pts with mMEL in a 21-day cycle. Pts must have had progressive disease (PD) on prior anti-PD-1. Mucosal MEL and asymptomatic brain metastases were allowed. Escalation cohorts had a 21-day SX-682 monotherapy (MONO) run-in. Response assessment by RECIST 1.1 was every 2 cycles during combination (COMBO) treatment. Primary endpoint was safety: adverse events (AEs), dose-limiting toxicity (DLT) and maximally-tolerated dose (MTD). Secondary endpoints included objective response rate (ORR; complete [CR] + partial [PR] response), disease control rate (DCR; CR + PR + stable disease [SD]) and overall survival (OS). Results: As of October 2023, 51 pts were enrolled and treated; median age of 65 (range 24-91), 55% male, 61% elevated LDH, 39% BRAF mutated. All pts received prior anti-PD-1, 37 (73%) received combined anti-PD-1 and anti-CTLA-4, and 23 (45%) had ≥ 3 prior therapies. Steady-state blood SX-682 was dose-proportional. No MONO DLT or MTD was identified. The 200 mg dose cohort was expanded in COMBO based on safety and pharmacodynamics: mg BID dose (n) = 25 (3), 50 (3), 100 (6), 150 (8), 200 (31). Any grade and grade 3/4 treatment-related AEs (TRAEs) occurred in 75% and 43%, respectively, and discontinuation (DC) due to TRAEs in 20% (when uncomplicated neutropenia, a permitted effect from CXCR2 inhibition on bone-marrow trafficking, was excluded there were 25% grade 3/4 TRAEs and 12% DC [rash, transaminitis]). There was no infectious signal. At the 200 mg dose, the ORR was 21% in 19 evaluable pts (4 PR + 0 CR) and the DCR was 63% (8 SD + 4 PR). DCR significantly depended on SX-682 dose ( P vs. ≤100 mg): 0% (0/9) at ≤100 mg, 50% (3/6) at 150 mg ( P = 0.0440) and 63% (12/19) at 200 mg ( P = 0.0028). All 15 pts with disease control had progressed on anti-PD-1 and anti-CTLA-4. Median OS was longer in pts in the 200 mg cohort (14.7 months; 95% CI, 10.5 – NR [not reached], n = 31) than in pts treated with ≤100 mg SX-682 (7.4 months; 95% CI, 5.0 – NR; n = 10). Conclusions: SX-682 combined with pem had a tolerable safety profile and activity reflected by objective responses and clinically meaningful disease control in heavily pretreated mMEL pts with progression on anti-PD-1 and anti–CTLA-4. Clinical trial information: NCT03161431 .

Efficacy and safety of surufatinib combined with EP regimen and serplulimab in first-line treatment of NEC.

e15123 Background: Neuroendocrine carcinomas (NEC) are more challenging than neuroendocrine tumors (NET) due to poor differentiation, aggressive invasion, and early diagnosis difficulties, often marked by local and distant metastasis at diagnosis, leading to poor outcomes. The ORR for NEC as first-line treatment with EP or EC regimens is approximately 30%, highlighting a substantial treatment gap. Surufatinib, a targeted small molecule kinase inhibitor, acts on vascular endothelial growth factor receptors (VEGFR-1/2/3), fibroblast growth factor receptor (FGFR-1), and colony-stimulating factor-1 receptor (CSF-1R). Its efficacy focuses on anti-angiogenesis and vascular normalization, alongside its role in modulating tumor-associated macrophages (TAMs) and boosting the effectiveness of immunotherapy. Methods: This single-arm, open-label, multicenter clinical study comprised a safety run-in (SR) phase and a dose-expansion (DE) phase. In the SR phase, six patients (pts) were planned to be enrolled to receive treatment with surufatinib (250 mg, QD, PO, Q3W) combined with the EP regimen (etoposide injection: 100mg/m2, d1-3, IV, Q3W; cisplatin: 25mg/m2, d1-3, IV, Q3W) and serplulimab (300mg, d1, IV, Q3W) for a maximum of six cycles, followed by a maintenance phase of surufatinib plus serplulimab until disease progression or other criteria as specified in the protocol. The dose of surufatinib in the DE phase was based on results from the SR phase. The primary endpoints were recommended Phase 2 dose (RP2D) and PFS, while secondary endpoints included ORR, DCR, OS, and safety. Results: As of December 27, 2023, this reports results from the SR phase. Six pts, median age 61.5 years (range 38-70), 66.7% male, all with ECOG performance status 1, were enrolled and completed their first treatment cycle. A majority (83.3%) had gastrointestinal-origin tumors with a median Ki-67% index of 70% (range 30%-90%). During the SR phase, one patient experienced Grade 4 hematologic toxicity (neutropenia and leukopenia) as a dose-limiting toxicity (DLT). Consequently, RP2D of surufatinib was established at 250mg for further research in the DE phase. The most common adverse events were neutropenia (50%), decreased white blood cell count (33.3%), fatigue (33.3%), and diarrhea (33.3%). Among those enrolled in the SR phase, 5 pts underwent at least one assessment of efficacy, yielding an objective response rate (ORR) of 60% and a disease control rate (DCR) of 100%, with the median progression-free survival (mPFS) not yet mature. Conclusions: Surufatinib combined with the EP regimen and serplulimab for NEC as first-line treatment showed notable efficacy and safety. The study established a phase II recommended surufatinib dose of 250mg, alongside immunotherapy and chemotherapy. Clinical trial information: NCT05747729 .

Preliminary data of a phase Ib/II trial evaluating the efficacy and safety of adebrelimab, camrelizumab plus apatinib as first-line therapy in patients with advanced hepatocellular carcinoma.

e16221 Background: The CARES-310 study has demonstrated that the combination of the anti-PD-1 antibody camrelizumab and the VEGFR2 tyrosine kinase inhibitor apatinib exhibits improved progression-free survival (PFS) and overall survival (OS) in patients with advanced hepatocellular carcinoma (HCC). We conducted this study to investigate whether the addition of the anti-PD-L1 antibody adebrelimab to camrelizumab and apatinib would further improve clinical outcomes. Methods: This is a prospective, phase 1b/2 clinical trial employing the i3 + 3 dose escalation design. Eligibility includes adults with unresectable or metastatic HCC, a ECOG PS of 0 or 1, a Child-Pugh score ≤ 7, and at least one measurable lesion per RECIST v 1.1. In phase 1b, patients (pts) received adebrelimab (10 mg/kg or 20 mg/kg, I.V., D1, Q3W), camrelizumab (200mg, I.V., D1, Q3W), and apatinib (250 mg orally daily). Phase 2 is a single arm, open-label trial in the first-line setting. The primary objective were dose-limiting toxicity (DLT), maximal tolerated dose (MTD), and recommended phase II dose (RP2D). With α = 0.05 and 80% power, the pts needed for stage I and total of the Simon 2-stage design was 17 and 41 pts, respectively. Results: As of 4 February 2024, 6 HCC pts progressed after or were intolerant to first-line treatment (systemic therapy ± surgical resection) were treated in 1 dose cohorts. 1 DLT occurred (Grade 3 elevated blood bilirubin increased). The RP2D was adebrelimab (10 mg/kg), camrelizumab (200mg), and apatinib (250 mg). The most common drug-related AEs were Hypertension (83.3%) and Rash (50%); and Serum amylase increased, Itching, ALT/AST increased, and Hypothyroidism (each 33.3%). Immune-related AEs were similar to those seen with other checkpoint blockade agents. No drug-related AEs led to death. 1 pts (16.7%) discontinued due to drug-related AEs. Conclusions: The combination of Adebelimumab, Camrelizumab, and Apatinib demonstrated manageable safety for unresectable HCC. Enrollment in the phase II trial is ongoing and updated clinical data will be presented. Clinical trial information: NCT05924997 .

Phase I study of copaiba aqueous mouthwash in patients with head and neck cancer undergoing radiotherapy.

e24103 Background: Due to the contraindication of low-power laser therapy in the tumor region, the use of copaiba for the management of oral mucositis was proposed, given its anti-inflammatory, antimicrobial and healing properties. This study aimed to evaluate the dose-limiting toxicity/maximum tolerated dose of copaiba aqueous mouthwash solution. Methods: This is a phase I study including patients with cavity or oropharynx cancer (CID-10 C00-C06,10), undergoing radiotherapy alone or associated with chemotherapy. Six successive cohorts were proposed, with a minimum of 3 patients each. The copaiba aqueous mouthwash was used daily starting on the first day of radiotherapy and up to 37 days, associated with Low Power Laser applications (100Mw, 660nm, beam area 0.09842 cm²,1J) in non-tumoral areas. In cohorts 1, 2, and 3, a 10% solution was used, and in cohorts 4, 5, and 6, 15%, 2, 3 and 4 times a day, respectively. Daily assessment was carried out evaluating the presence of oral mucositis lesions (World Health Organization and Oral Mucositis Assessment Scale) and complaints of pain (CTCAE v5.0 and Visual Analogue Pain Scale) and xerostomia (presence or absence). Sialometry was carried out through the collection of unstimulated saliva (by Davies (2002) criteria), once a week. Results: Twenty patients were included (cohort 1 = 5, cohort 2 = 3, cohort 3 = 3, cohort 4 = 3, cohort 5 = 3, cohort 6 = 3) - 1 patient was excluded and 1 discontinued from cohort 1 (due to changes in radiotherapy planning and non-adherence to dentistry appointments). A total of 19 participants used the mouthwash. Most of the participants were women (57.9%), with a median age of 63.2 years, and performance status 1 (84.2%). Most tumors were squamous cell carcinomas (84.2%), 47.4% of them in the palate; 57.9% were staged as IVA. Themedian total radiotherapy dose was 68.0 (60.0-70.0) Gy delivered in 33.0 (30.0-34.5) fractions. Pain in the oral cavity (73.7%) and oropharynx (52.6%) were referred, graded respectively as 4.5 (0.75-7) and 1.5 (0-6). Oral mucositis was classified as grade 3 at most; none of the patients developed grade 4 or had to have radiotherapy interrupted due to toxicity. Ulcerated lesions of oral mucositis developed in the tumor area in 68.4% of patients and non-tumor areas in 84.2%. Patients complained of xerostomia in 73.7% of cases and the median unstimulated sialometry was 0.17mL/min. None of the patients experienced dose-limiting toxicity related to the copaiba solution. Conclusions: Copaiba mouthwash did not trigger dose-limiting toxicity in any of the patients throughout the study, leading to amaximum tolerated dose of 15%, 4 times/day. None of the patients complained of pain or burning related to the use of mouthwash in the absence of oral mucositis lesions, suggesting that it is safe and non-toxic for this use. In this sense, considering the obtained results, the development of a phase II study becomes the next logical step in this research area. Clinical trial information: ID - 34635020.5.0000.5274.

CTEP 10492, a phase 1/1b study of the AKT inhibitor ipatasertib with chemoradiation for locally advanced head and neck squamous cell carcinoma.

TPS6127 Background: Locally advanced head and neck squamous cell carcinoma (HNSCC) is commonly treated with definitive chemoradiation therapy (CRT). However, locoregional recurrence rates of approximately 50% may occur in high risk patients. As such, there is an unmet need for up-front treatment intensification in this patient population. Preclinical evidence suggests that both radiation therapy (RT) and cisplatin activate the PI3K/AKT pathway, leading to treatment resistance through multiple processes, including increased DNA repair, decreased apoptosis, and modulation of the tumor microenvironment by promoting angiogenesis, immune escape and hypoxia. Furthermore, AKT inhibitors have been shown to sensitize a subset of HNSCC models to RT and platinum chemotherapy in vitro and in vivo. However, radiosensitization using a specific AKT inhibitor has not yet been studied in humans. This phase I studywill bethe first to establish safety and preliminary efficacy of ipatasertib combined with standard of care definitive CRT for HNSCC. Methods: The primary objective of this study is to determine the maximum tolerated dose and recommended Phase 2 dose (RP2D) of ipatasertib in combination with definitive CRT in locally advanced HNSCC based on dose-limiting toxicities (DLTs). Secondary objectives include assessment of acute and late toxicities, long term swallowing function, and a preliminary assessment of efficacy. Eligible subjects must have pathologically confirmed, previously untreated, non-metastatic HNSCC that is either human papilloma virus (HPV)-negative clinical stage III-IVB, or HPV-positive clinical stage III. The study schema includes dose escalation and expansion cohorts. All subjects will receive RT for a standard 70 Gy in 7-week course, with concurrent weekly cisplatin. Two 28-day cycles of orally administered ipatasertib will be given concurrently with CRT. The four dose levels of ipatasertib range from 100-400 mg daily. Dose escalation of ipatasertib will follow a Time-to-Event Bayesian Optimal Interval (TITE-BOIN) design, with DLT window extending from the start of CRT, through 28 days after completion of RT. The expansion cohort will enroll an additional 10 subjects at the RP2D, and incorporate pharmacodynamic biopsies for each subject to evaluate whether the addition of ipatasertib to CRT will result in increased gamma-H2AX, consistent with radiosensitization, and also decreased pS6 and pPRAS40 to evaluate AKT pathway inhibition. Additional correlative studies include assessment of the pharmacokinetic profile of ipatasertib with CRT, as well as correlation of efficacy with tumor genotype, based on whole exome sequencing of pre-treatment biopsy specimens. Enrollment is currently at dose level 2 in the escalation phase, and is expected to complete accrual in 2025. Clinical trial information: NCT05172245 .

Safety, tolerability, pharmacokinetics and clinical activity of AST-3424, an AKR1C3-activated bis-alkylating moiety prodrug, in subjects with advanced solid tumors in China: A phase I dose-escalation study.

3121 Background: Aldo-keto reductase family 1 member C3 (AKR1C3) modulates cellular differentiation and proliferation through indirect regulation of ligand access to hormone and nuclear receptor signaling. AKR1C3 is expressed at high levels in various human cancers, including hepatocellular carcinoma (HCC). AST-3424 is an AKR1C3-activated prodrug and releases a toxic bis-alkylating moiety (AST-2660) in the presence of AKR1C3, which forms intra- and inter-strand DNA crosslinks resulting in cell death. Here we report the results of a phase I dose escalation study of AST-3424 in patients with advanced solid tumors (NCT06239155). Methods: Patients with histologically and/or cytologically confirmed advanced solid tumors who failed standard treatment or no standard treatment, or not suitable for standard treatment were enrolled to receive AST-3424 intravenously (i.v.) at doses of 1, 2, 4, 6, 8 mg/m2 on Day 1 and Day 8 every 21 days. A parallel and accelerated titration for 1 and 2 mg/m2, and 3+3 dose escalation design for other cohorts were used to guide dose escalation and maximum tolerable dose (MTD) determination. Results: 21 subjects were enrolled and received at least one treatment (HCC=4, colorectal cancer=6, gastric cancer=4, pancreatic carcinoma=2, breast cancer=2, intrahepatic cholangiocarcinoma=1, prostate cancer=1, salivary gland cancer=1). 4 dose-limiting toxicities (DLTs) were observed (3 grade 4 platelet count decreased; 1 grade 2 gamma-glutamyltransferase increased, DLT reported due to dosing delayed more than 14 days). Safety Review Committee confirmed 6.0 mg/m2 as the MTD and recommended Phase 2 dose (RP2D). Grade≥3 adverse events (AEs) were observed in in 10 patients (47.6%). 8 patients (38.1%) had grade≥3 treatment-related AEs (TRAEs), being anemia (33.3%), platelet count decreased (19.0%), white blood cell count decreased (9.5%) and neutrophil count decreased (9.5%). Most of the grade≥3 AEs were observed in the 8.0 mg/m2 cohort. No patient had a fatal TRAE. 15 subjects with baseline target lesions had at least one post baseline assessment. 9 subjects (42.9%) had stable disease (SD); 1 subject (4.8%) had non-complete remission/non-disease progression (Non-CR/Non-PD); 5 subjects (23.8%) had progressive disease (PD). AST-3424 showed linear pharmacokinetic characteristics in the range of 1.0-8.0 mg/m2 with a half-life of 0.16-0.40 hours. AST-2660 showed linear pharmacokinetic characteristics in the range of 4.0-8.0 mg/m2 with a half-life of 1.59-2.08 hours. Conclusions: AST-3424 showed a tolerable safety profile and preliminary anti-tumor activity in advanced solid tumors. The phase II dose expansion phase of AST-3424 monotherapy is ongoing in subjects diagnosed as advanced HCC and with high AKR1C3 expression. Clinical trial information: NCT06239155 .

Safety of pressurized intraperitoneal aerosolized chemotherapy (PIPAC) in patients (pts) with biliary tract cancer with peritoneal metastases.

TPS4186 Background: Biliary tract cancers are rare with the majority of pts diagnosed with metastatic disease at initial presentation. Up to 20% of pts will have peritoneal metastases, resulting in symptoms of ascites, abdominal pain, and potential bowel obstruction. Despite advances in standard of care systemic treatments such as combination gemcitabine, cisplatin, and durvalumab (gem/cis/durva), penetration to peritoneal metastases may be poor. While addition of nab-paclitaxel to gem/cis increased objective response in a phase 2 study (1), SWOG 1815 did not demonstrate a significant improvement in survival with the triplet combination compared to gem/cis (2), possibly due to added toxicity. PIPAC directly delivers treatment to the peritoneal space, which could potentially reduce toxicity and improve efficacy. We aim to investigate the safety of PIPAC nab-paclitaxel plus systemic gem/cis/durva in biliary tract cancer pts with peritoneal metastases. Methods: This is an investigator-initiated, non-randomized phase 1 trial enrolling up to 12 evaluable pts using a modified phase 1 queue 3+3 design. Eligible pts must have treatment-naïve histologically or cytologically confirmed intra/extra-hepatic cholangiocarcinoma or gallbladder cancer with documented metastatic disease and visible peritoneal disease on imaging or laparoscopy. Gem/cis (800/25 mg/m2) will be administered on Days 1 and 8 of 3-week cycles; durva (1500 mg) will be administered on Day 1. Pts will receive PIPAC nab-paclitaxel (90 mg/m2) on Day 3 of Cycles 1, 3, and 5. If dose-limiting toxicities (DLTs) occur, nab-paclitaxel may be reduced to 70 mg/m2; the DLT window for each pt is 42 days after the first PIPAC. After eight 3-week cycles, durva (1500 mg) will be continued on Day 1 of 4-week cycles until disease progression or unacceptable toxicity. The primary endpoint is treatment-related adverse events (AEs) graded by NCI Common Terminology Criteria for Adverse Events version (v) 5.0. AEs will be monitored during treatment and for 4 weeks after the last dose of treatment with any agent. Secondary endpoints include objective response per Response Evaluation Criteria in Solid Tumors v1.1, peritoneal regression grading score at each PIPAC, peritoneal carcinomatosis index at time of laparoscopy, post-operative surgical complications, progression-free/overall survival, PIPAC technical failure rate, EQ-5D-5L and MD Anderson Symptom Inventory responses before/during treatment, and number of daily steps taken before/during treatment. Exploratory endpoints include characterization of sub-clonal tumor evolution/tumor microenvironment changes and PIPAC nab-paclitaxel pharmacokinetics/pharmacodynamics. Enrollment began 6/2023 and is ongoing. 1. Shroff et al, JAMA Oncol 2019. 2. Shroff et al, JCO 2023 LBA490. Clinical trial information: NCT05285358 .

A phase I study of highly potent oral ATR inhibitor (ATRi) tuvusertib plus oral PARP inhibitor (PARPi) niraparib in patients with solid tumors.

3018 Background: Ataxia telangiectasia and Rad3-related (ATR) protein kinase and poly-ADP ribose polymerases (PARPs) are crucial components in the DNA damage response (DDR). Combining tuvusertib and niraparib may synergistically enhance synthetic lethality and increase apoptosis. Part B1 of the DDRiver Solid Tumors 301 study (NCT04170153) assessed this combination. Methods: Part B1 of this open-label multicenter dose-escalation phase Ib trial enrolled unselected patients with metastatic or locally advanced unresectable solid tumors refractory to standard treatment. The primary objective was to determine safety (including maximum tolerable dose and recommended dose(s) for expansion [RDE]). Secondary and tertiary objectives included determination of the pharmacokinetics (PK), pharmacodynamics (PD), and preliminary efficacy of different dosing regimens of tuvusertib plus niraparib. Multiple continuous and intermittent schedules were explored with tuvusertib doses ranging from 90–180 mg once-daily (QD) and niraparib doses from 100–200 mg QD. A partial ordering continual reassessment method was used to identify the RDEs. Results: As of 02 January 2024, 43 patients had been enrolled (all with baseline body weight <77kg or platelet count <150,000/mm3); 13 patients remained on treatment. Ten (26.3%) patients had dose-limiting toxicities (DLTs). The most common DLT was grade 3 anemia requiring blood transfusion (n=4; 10.5%); the most frequent grade ≥3 treatment-emergent adverse events were anemia (n=18; 41.9%), platelet count decrease (n=6; 14.0%) and fatigue (n=4; 9.3%). The PK of tuvusertib when combined with niraparib was consistent with that of tuvusertib monotherapy, suggesting a lack of any clinically meaningful mutual drug–drug interactions. Dose-dependent ɣ-H2AX inhibition (proximal PD marker) was observed at tuvusertib doses ≥130 mg QD. Preliminary efficacy data show 5 (15.6%) responses (3 confirmed) by RECIST v1.1 in 32 evaluable patients: 2 in patients with epithelial ovarian cancer (EOC; 1 with BRCA1-mutant [ BRCA1m] PARPi-resistant EOC, 1 with BRCA-wild type homologous recombination deficiency-positive EOC) and 1 each in patients with non-small cell lung cancer, estrogen receptor-positive HER2-negative BRCA1m breast cancer, and BRCA1m PARPi-resistant pancreatic cancer. Tuvusertib 180 mg QD and niraparib 100 mg QD or tuvusertib 90 mg QD and niraparib 200 mg QD, both given in a 1 week on/1 week off schedule, were identified as RDEs. Conclusions: The combination of tuvusertib plus niraparib, each administered on a 1 week on/1 week off schedule, has a manageable safety profile and is suitable for further investigation. A combination study in patients with PARPi-resistant EOC is planned. Clinical trial information: NCT04170153 .

A phase I/II study of KD6001, a novel fully human anti-CTLA4 IgG1 monoclonal antibody, in combination with toripalimab in patients with advanced melanoma.

9527 Background: Anti-CTLA4 and anti-PD-1 immunotherapies have changed the treatment landscape of patients (pts) with advanced or metastatic melanoma. However, there is still a need to develop an anti-CTLA-4 antibody with further improved safety and efficacy profile. KD6001, a novel fully human anti-CTLA4 IgG1 monoclonal antibody that exhibits immunomodulatory effects, enhances T-cell-mediated anti-tumor immune response, and shows preliminary anti-tumor activity as monotherapy in a FIH phase I trial in pts with advanced solid tumors. Here we report a new study result of KD6001 in combination with toripalimab, an anti-PD-1 monoclonal antibody, in pts with advanced melanoma (KD6001CT02). Methods: KD6001CT02 is a phase I/II study conducted in advanced melanoma. This study consists of dose escalation and dose expansion phases. The primary objective is to evaluate the safety and tolerability of KD6001 in combination with toripalimab and determine the MTD/RP2D. The secondary objectives are to measure antitumor activity, immunogenicity, and pharmacokinetics (PK). Results: As of 15 Dec 2023, 29 pts with melanoma were enrolled (dose escalation n=6 and dose expansion n=23), including 9 (31.0%) acral, 9 (31.0%) nonacral cutaneous, 8 (27.6%) mucosal, and 3 (10.3%) unknown primary subtypes. 18 of them had no brain metastases. The median age was 56 yrs (range 41-78 yrs). The majority of pts previously received anti-PD-1/L1 therapy (16/29, 55.2%) and 27.6% of them received ≥3 lines of therapy. No dose-limiting toxicity or ≥Gr 3 adverse events (AEs) were reported in the dose escalation phase. The study did not reach MTD. 26 (89.7%) pts had treatment-related adverse events (TRAEs), with ≥Gr 3 TRAEs occurring in 3 (10.3%) pts and were well manageable. All other TRAEs were Gr 1 or 2. There were no death events due to TRAEs. No novel safety signals were seen other than the previously reported safety profile of treatment with a combined inhibition of CTLA-4 and PD-1. At data cutoff, among 13 efficacy-evaluable pts without brain metastases, the unconfirmed and confirmed objective response rates (ORR) were 38.5% and 23.1%, respectively. The disease control rate (DCR) was 76.9%. Among 3 pts with confirmed partial response (PR) , 2 pts were mucosal melanoma and 1 patient was nonacral cutaneous melanoma. Among 7 pts who received KD6001 as the ≥2 line treatment and all failed anti-PD-1/L1 therapy, the unconfirmed and confirmed ORR were 57.1% and 42.9%, respectively. DCR was 85.7%. The median PFS and OS were not reached. Conclusions: KD6001 in combination with toripalimab for treatment of advanced melanoma was safe, well-tolerated and showed anti-tumor activity in pts with advanced melanoma. Preliminary analysis indicates that KD6001 combined with toripalimab is efficacious in pts who have progressed after previous anti-PD-1/L1 therapy and in pts with mucosal melanoma. Clinical trial information: NCT05723432 .