Targeting T regulatory (Treg) cells in immunotherapy-resistant cancers.

Primary or secondary (i.e., acquired) resistance is a common occurrence in cancer patients and is often associated with high numbers of T regulatory (Treg) cells (CD4+CD25+FOXP3+). The approval of ipilimumab and the development of similar pharmacological agents targeting cell surface proteins on Treg cells demonstrates that such intervention may overcome resistance in cancer patients. Hence, the clinical development and subsequent approval of Cytotoxic T Lymphocyte Antigen-4 (CTLA-4) targeting agents can serve as a prototype for similar agents. Such new agents aspire to be highly specific and have a reduced toxicity profile while increasing effector T cell function or effector T/T regulatory (Teff/Treg) ratio. While clinical development with large molecules has shown the greatest advancement, small molecule inhibitors that target immunomodulation are increasingly entering early clinical investigation. These new small molecule inhibitors often target specific intracellular signaling pathways [e.g., phosphoinositide-3-kinase delta (PI3K-δ)] that play an important role in regulating the function of Treg cells. This review will summarize the lessons currently applied to develop novel clinical agents that target Treg cells.

The highly selective and oral phosphoinositide 3-kinase delta (PI3K-δ) inhibitor roginolisib induces apoptosis in mesothelioma cells and increases immune effector cell composition.

Targeting aberrantly expressed kinases in malignant pleural mesothelioma (MPM) is a promising therapeutic strategy. We here investigated the effect of the novel and highly selective Phosphoinositide 3-kinase delta (PI3K-δ) inhibitor roginolisib (IOA-244) on MPM cells and on the immune cells in MPM microenvironment. To this aim, we analyzed the expression of PI3K-δ by immunohistochemistry in specimens from primary MPM, cell viability and death in three different MPM cell lines treated with roginolisib alone and in combination with ipatasertib (AKT inhibitor) and sapanisertib (mTOR inhibitor). In a co-culture model of patient-derived MPM cells, autologous peripheral blood mononuclear cells and fibroblasts, the tumor cell viability and changes in immune cell composition were investigated after treatment of roginolisib with nivolumab and cisplatin. PI3K-δ was detected in 66/89 (74%) MPM tumors and was associated with reduced overall survival (12 vs. 25 months, P=0.0452). Roginolisib induced apoptosis in MPM cells and enhanced the anti-tumor efficacy of AKT and mTOR kinase inhibitors by suppressing PI3K-δ/AKT/mTOR and ERK1/2 signaling. Furthermore, the combination of roginolisib with chemotherapy and immunotherapy re-balanced the immune cell composition, increasing effector T-cells and reducing immune suppressive cells. Overall, roginolisib induces apoptosis in MPM cells and increases the antitumor immune cell effector function when combined with nivolumab and cisplatin. These results provide first insights on the potential of roginolisib as a therapeutic agent in patients with MPM and its potential in combination with established immunotherapy regimen.

The future of targeting cytotoxic T-lymphocyte-associated protein-4: Is there a role?

The 2022 yearly Think Tank Meeting in Siena, Tuscany (Italy), organized by the Italian Network for Tumor Biotherapy (NIBIT) Foundation, the Parker Institute for Cancer Immunotherapy and the World Immunotherapy Council, included a focus on the future of integrating and expanding the use of targeting cytotoxic T-lymphocyte-associated protein 4 (CTLA-4). The conference members exchanged their views on the lessons from targeting CTLA-4 and compared the effect to the impact of blocking Programmed cell death protein 1 (PD1) or its ligand (PDL1). The increasing experience with both therapeutic approaches and their combination suggests that targeting CTLA-4 may lead to more durable responses for a sizeable proportion of patients, though the specific mechanism is not entirely understood. Overcoming toxicity of blocking CTLA-4 is currently being addressed with different doses and dose regimens, especially when combined with PD1/PDL1 blocking antibodies. Novel therapeutics targeting CTLA-4 hold the promise to reduce toxicities and thus allow different combination strategies in the future. On the whole, the consent was that targeting CTLA-4 remains an important strategy to improve the efficacy of cancer immunotherapies.

Autotaxin Secretion Is a Stromal Mechanism of Adaptive Resistance to TGFß Inhibition in Pancreatic Ductal Adenocarcinoma.

The TGFß receptor inhibitor galunisertib demonstrated efficacy in patients with pancreatic ductal adenocarcinoma (PDAC) in the randomized phase II H9H-MC-JBAJ study, which compared galunisertib plus the chemotherapeutic agent gemcitabine with gemcitabine alone. However, additional stromal paracrine signals might confer adaptive resistance that limits the efficacy of this therapeutic strategy. Here, we found that autotaxin, a secreted enzyme that promotes inflammation and fibrosis by generating lysophosphatidic acid (LPA), mediates adaptive resistance to TGFß receptor inhibition. Blocking TGFß signaling prompted the skewing of cancer-associated fibroblasts (CAF) toward an inflammatory (iCAF) phenotype. iCAFs were responsible for a significant secretion of autotaxin. Paracrine autotaxin increased LPA-NFκB signaling in tumor cells that triggered treatment resistance. The autotaxin inhibitor IOA-289 suppressed NFκB activation in PDAC cells and overcame resistance to galunisertib and gemcitabine. In immunocompetent orthotopic murine models, IOA-289 synergized with galunisertib in restoring sensitivity to gemcitabine. Most importantly, treatment with galunisertib significantly increased plasma levels of autotaxin in patients enrolled in the H9H-MC-JBAJ study, and median progression-free survival was significantly longer in patients without an increase of autotaxin upon treatment with galunisertib compared with those with increased autotaxin. These results establish that autotaxin secretion by CAFs is increased by TGFß inhibition and that circulating autotaxin levels predict response to the combination treatment approach of gemcitabine plus galunisertib. SIGNIFICANCE: TGFß inhibition skews cancer-associated fibroblasts toward an inflammatory phenotype that secretes autotaxin to drive adaptive resistance in PDAC, revealing autotaxin as a therapeutic target and biomarker of galunisertib response.

Non-Clinical Toxicology Evaluation of the Novel Non-ATP Competitive Oral PI3 Kinase Delta Inhibitor Roginolisib.

Roginolisib (IOA-244) is a novel, non-ATP competitive phosphoinositide-3-kinase (PI3K) delta inhibitor that regulates Akt/mTOR signaling. Roginolisib was administered once daily to rats and dogs in dose-range finding (DRF) and 4-week GLP toxicology studies. Free plasma levels of roginolisib exceeded the cellular target engagement IC90 for PI3Kδ for ≥12 hours at doses of 5 mg/kg, the IC90 for PI3Kß for ≥2 hours at doses ≥15 mg/kg, and the IC50 for PI3Kα for ≥2 hours at dose levels ≥45 mg/kg. Toxicity in rats occurred at doses ≥100 mg/kg. In dogs, we observed dose-dependent skin and gastrointestinal toxicity and doses ≥30 mg/kg had a greater incidence of mortality. Lymphoid tissue toxicity occurred in both species. Toxicities in dogs observed at the ≥15 mg/kg dose, affecting the digestive mucosa, liver, and skin, cleared after treatment cessation. Doses ≤75 mg/kg were tolerated in rats and the no-observed-adverse-effect-level (NOAEL) in rats was 15 mg/kg. Due to mainly epithelial lesions of the skin at 5 mg/kg and necrotizing damage of the intestinal epithelia at ≥15 mg/kg, no NOAEL was determined in dogs. However, the adverse effects observed in dogs at 5 mg/kg were considered monitorable and reversible in patients with advanced malignancies. Furthermore, the PK profile subsequently proved to be a decisive factor for achieving selective PI3Kδ inhibition without the toxicities observed in dogs. As the result of the unique PK profile of roginolisib, patients were able to take daily roginolisib without dose modification and showed pharmacodynamic PI3Kδ inhibition over several months without gastrointestinal or dermatologic toxicities.

Autotaxin inhibitor IOA-289 reduces gastrointestinal cancer progression in preclinical models.

BACKGROUND: Autotaxin (ATX) is a secreted enzyme that converts lysophosphatidylcholine to lysophosphatidic acid (LPA). LPA stimulates cell proliferation and migration and promotes wound repair following tissue damage. ATX levels are directly correlated with stage and grade in several human cancers. Several small molecule ATX inhibitors have been developed in recent years. IOA-289 is a potent ATX inhibitor, developed to treat cancers containing fibrosis. In this study, we tested IOA-289 treatment on different gastrointestinal tract tumor cell lines, in order to evaluate its effects on viability and motility. METHODS: To determine the effects on cell viability and proliferation of treatment with increasing concentrations of IOA-289, we used the crystal violet assay, a clonogenic assay in matrigel, and we evaluated the inhibitor's effect on formation of 3D spheroids in an in vitro model. The effect of IOA-289 on cell cycle phases was analysed with a redox dye reagent. Cell migration capacity was evaluated by wound healing assay and transwell migration assay. To evaluate the pro-apoptotic effect of the inhibitor, cells were stained with Annexin V and immunofluorescence and flow cytometry analysis were performed. An antibody array was also used, to discriminate, in various samples, the differential expression of 43 proteins involved in the apoptosis pathway. RESULTS: We found that IOA-289 is able to inhibit both growth and migration of gastrointestinal tract tumor cell lines, both in 2D (crystal violet assay) and 3D in vitro models (spheroid formation and clonogenic assay in matrigel). This effect is dose-dependent, and the drug is most effective when administered in FBS-free culture medium. The inhibitory effect on cell growth is due to a pro-apoptotic effect of IOA-289. Staining with FITC-conjugated Annexin V showed that IOA-289 induced a dose-dependent increase in fluorescence following incubation for 24 h, and apoptotic cells were also distinguished in flow cytometry using Annexin/PI staining. The antibody array shows that treatment with IOA-289 causes the increased expression of several pro-apoptotic proteins in all tested cell lines. CONCLUSIONS: These results indicate that IOA-289 may be an effective drug for the treatment of tumors of the gastrointestinal tract, particularly those characterized by a high degree of fibrosis.

IOA-244 is a Non-ATP-competitive, Highly Selective, Tolerable PI3K Delta Inhibitor That Targets Solid Tumors and Breaks Immune Tolerance.

PI3K delta (PI3Kδ) inhibitors are used to treat lymphomas but safety concerns and limited target selectivity curbed their clinical usefulness. PI3Kδ inhibition in solid tumors has recently emerged as a potential novel anticancer therapy through the modulation of T-cell responses and direct antitumor activity. Here we report the exploration of IOA-244/MSC2360844, a first-in-class non-ATP-competitive PI3Kδ inhibitor, for the treatment of solid tumors. We confirm IOA-244's selectivity as tested against a large set of kinases, enzymes, and receptors. IOA-244 inhibits the in vitro growth of lymphoma cells and its activity correlates with the expression levels of PIK3CD, suggesting cancer cell-intrinsic effects of IOA-244. Importantly, IOA-244 inhibits regulatory T cell proliferation while having limited antiproliferative effects on conventional CD4+ T cells and no effect on CD8+ T cells. Instead, treatment of CD8 T cells with IOA-244 during activation, favors the differentiation of memory-like, long-lived CD8, known to have increased antitumor capacity. These data highlight immune-modulatory properties that can be exploited in solid tumors. In CT26 colorectal and Lewis lung carcinoma lung cancer models, IOA-244 sensitized the tumors to anti-PD-1 (programmed cell death protein 1) treatment, with similar activity in the Pan-02 pancreatic and A20 lymphoma syngeneic mouse models. IOA-244 reshaped the balance of tumor-infiltrating cells, favoring infiltration of CD8 and natural killer cells, while decreasing suppressive immune cells. IOA-244 presented no detectable safety concerns in animal studies and is currently in clinical phase Ib/II investigation in solid and hematologic tumors. Significance: IOA-244 is a first-in-class non-ATP-competitive, PI3Kδ inhibitor with direct antitumor in vitro activity correlated with PI3Kδ expression. The ability to modulate T cells, in vivo antitumor activity in various models with limited toxicity in animal studies provides the rationale for the ongoing trials in patients with solid tumors and hematologic cancers.

Immunotherapy for brain metastases and primary brain tumors.

During the V Siena Immuno-Oncology (IO) Think Tank meeting in 2021, conditions were discussed which favor immunotherapy responses in either primary or secondary brain malignancies. Core elements of these discussions have been reinforced by important publications in 2021 and 2022. In primary brain tumors (such as glioblastoma) current immunotherapies have failed to deliver meaningful clinical benefit. By contrast, brain metastases frequently respond to current immunotherapies. The main differences between both conditions seem to be related to intrinsic factors (e.g., type of driver mutations) and more importantly extrinsic factors, such as the blood brain barrier and immune suppressive microenvironment (e.g., T cell counts, functional differences in T cells, myeloid cells). Future therapeutic interventions may therefore focus on rebalancing the immune cell population in a way which enables the host to respond to current or future immunotherapies.

A vision of immuno-oncology: the Siena think tank of the Italian network for tumor biotherapy (NIBIT) foundation.

BACKGROUND: The yearly Think Tank Meeting of the Italian Network for Tumor Biotherapy (NIBIT) Foundation, brings together in Siena, Tuscany (Italy), experts in immuno-oncology to review the learnings from current immunotherapy treatments, and to propose new pre-clinical and clinical investigations in selected research areas. MAIN: While immunotherapies in non-small cell lung cancer and melanoma led to practice changing therapies, the same therapies had only modest benefit for patients with other malignancies, such as mesothelioma and glioblastoma. One way to improve on current immunotherapies is to alter the sequence of each combination agent. Matching the immunotherapy to the host's immune response may thus improve the activity of the current treatments. A second approach is to combine current immunotherapies with novel agents targeting complementary mechanisms. Identifying the appropriate novel agents may require different approaches than the traditional laboratory-based discovery work. For example, artificial intelligence-based research may help focusing the search for innovative and most promising combination partners. CONCLUSION: Novel immunotherapies are needed in cancer patients with resistance to or relapse after current immunotherapeutic drugs. Such new treatments may include targeted agents or monoclonal antibodies to overcome the immune-suppressive tumor microenvironment. The mode of combining the novel treatments, including vaccines, needs to be matched to the patient's immune status for achieving the maximum benefit. In this scenario, specific attention should be also paid nowadays to the immune intersection between COVID-19 and cancer.

Correction: Biomarkers and overall survival in patients with advanced hepatocellular carcinoma treated with TGF-ßRI inhibitor galunisertib.

[This corrects the article DOI: 10.1371/journal.pone.0222259.].

Neoadjuvant immunotherapy is reshaping cancer management across multiple tumour types: The future is now!

The Italian Network for Tumor Biotherapy (Network Italiano per la Bioterapia dei Tumori [NIBIT]) Foundation hosted its annual 2020 Think Tank meeting virtually, at which representatives from academic, clinical, industry, philanthropic, and regulatory organisations discussed the role of neoadjuvant immunotherapy for the treatment of cancer. Although the number of neoadjuvant immunotherapeutic trials is increasing across all malignancies, the Think Tank focused its discussion on the status of neoadjuvant trials in cutaneous melanoma (CM), muscle-invasive urothelial bladder cancer (MIBC), head and neck squamous cell carcinoma (HNSCC), and pancreatic adenocarcinoma (PDAC). Neoadjuvant developments in CM are nothing short of trailblazing. Pathologic Complete Response (pCR), pathologic near Complete Response, and partial Pathologic Responses reduce 90-100% of recurrences. This is in sharp contrast to targeted therapies in neoadjuvant CM trials, where only a pCR seems to reduce recurrence. The pCR rate after neoadjuvant immunotherapy varies among the different malignancies of CM, MIBC, HNSCC, and PDAC and may be associated with different reductions of recurrence rates. In CM, emerging evidence suggests that neoadjuvant immunotherapy with anti-CTLA-4 plus anti-PD1 is a game changer in patients with palpable nodal Stage III or resectable Stage IV disease by curing more patients, reducing recurrences and the need for surgical interventions, such as lymph node dissections and metastasectomies. The Think Tank panel discussed future approaches on how to optimise results across different tumour types. Future approaches should include reducing monocyte-mediated (tumour-associated macrophages) and fibroblast-mediated (cancer-associated fibroblasts) barriers in the tumour microenvironment to facilitate the recruitment of immune cells to the tumour site, to reduce immune-suppressive mediators, and to increase antigen presentation at the site of the tumour.

Phase 1b study of galunisertib and ramucirumab in patients with advanced hepatocellular carcinoma.

BACKGROUND: Preclinical data suggest that vascular endothelial growth factor (VEGF) and transforming growth factor (TGF)-ß signaling interact to stimulate angiogenesis and suppress antitumor immune responses. Thus, combined inhibition of both pathways may offer greater antitumor activity compared with VEGF-targeted antiangiogenic monotherapy against hepatocellular carcinoma (HCC). METHODS: This is a multicenter, open-label, phase 1b study of galunisertib, an inhibitor of TGF-ß receptor 1, and ramucirumab, an anti-VEGF receptor 2 antibody, in patients with advanced HCC aiming to define the maximum tolerated dose (MTD). Secondary objectives included safety, pharmacokinetics (PK), antitumor efficacy, and plasma alpha-fetoprotein and TGF-ß kinetics. Dose escalation employed a 3 + 3 design. Patients received galunisertib at 80 mg (cohort 1) or 150 mg (cohort 2) orally twice a day on days 1-14 of a 28-day cycle combined with ramucirumab 8 mg/kg intravenously every 2 weeks. RESULTS: Eight patients were enrolled: three in cohort 1 and five in cohort 2 (two patients were unevaluable due to rapid disease progression and replaced). No dose-limiting toxicities were observed. Treatment-related adverse events (AEs) of any grade in ≥2 patients included nausea (25%) and vomiting (25%). There was one Grade 3 treatment-related AE, a cerebrovascular accident possibly related to ramucirumab. Galunisertib exposure was dose-proportional and not affected by ramucirumab. The RECIST version 1.1 objective response rate and disease control rate were 0% and 12.5%, respectively. CONCLUSION: Combination therapy was safe and tolerable and displayed favorable PK. The MTD was established at galunisertib at 150 mg orally twice a day and ramucirumab 8 mg/kg intravenously every 2 weeks. The results do not support the preclinical hypothesis that blocking TGFß signaling enhances efficacy of VEGF-targeted therapy; thus further clinical development was halted for the combination of galunisertib and ramucirumab.

A First-in-Human Dose Finding Study of Camrelizumab in Patients with Advanced or Metastatic Cancer in Australia.

PURPOSE: Camrelizumab inhibits PD-1 in non-clinical models and showed typical non-clinical pharmacokinetic (PK) and safety profiles for an IgG4 monoclonal antibody. We report results from the First-in-Human Phase 1 trial of camrelizumab in Australian population. METHODS: Camrelizumab was administered to patients with advanced solid tumors who had failed standard therapies. In the dose-escalation phase (n=23), camrelizumab was administered intravenously at 1 mg/kg, 3 mg/kg, 6 mg/kg, and 10 mg/kg every 2 weeks. In dose expansion (n=26), camrelizumab was given at 200 mg or 600 mg every 4 weeks. RESULTS: Two dose-limiting toxicities were observed during dose escalation: transaminase elevation and diarrhea (both grade 3). Overall, treatment-related adverse events were consistent with the expected toxicity profile of immune checkpoint inhibition, with the striking exception of the dose-related development of angiomatous skin lesions characterized as reactive cutaneous capillary endothelial proliferation. The PK profile showed a dose-progressive increase in half-life from 3 days at 1 mg/kg to 7 days at 10 mg/kg. Moreover, receptor occupancy assays showed a PD-1 occupancy of >50% in most patients out to 28 days post-dose. The objective response rate was 15.2% (95% CI 6.3-28.9). CONCLUSION: Camrelizumab has manageable toxicity and encouraging preliminary antitumor activity in advanced solid tumors in Australia. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02492789.

Phase 1b/2a study of galunisertib, a small molecule inhibitor of transforming growth factor-beta receptor I, in combination with standard temozolomide-based radiochemotherapy in patients with newly diagnosed malignant glioma.

Purpose Galunisertib, a TGF-ß inhibitor, has demonstrated antitumor effects in preclinical and radiographic responses in some patients with malignant glioma. This Phase 1b/2a trial investigated the clinical benefit of combining galunisertib with temozolomide-based radiochemotherapy (TMZ/RTX) in patients with newly diagnosed malignant glioma (NCT01220271). Methods This is an open-label, 2-arm Phase 1b/2a study (N = 56) of galunisertib (intermittent dosing: 14 days on/14 days off per cycle of 28 days) in combination with TMZ/RTX (n = 40), versus a control arm (TMZ/RTX, n = 16). The primary objective of Phase 1b was to determine the safe and tolerable Phase 2 dose of galunisertib. The primary objective of Phase 2a was to confirm the tolerability and pharmacodynamic profile of galunisertib with TMZ/RTX, and the secondary objectives included determining the efficacy and pharmacokinetic (PK) profile of galunisertib with TMZ/RTX in patients with glioblastoma. This study also characterized the changes in the major T-cell subsets during TMZ/RTX plus galunisertib treatment. Results In the Phase 2a study, efficacy results for patients treated with galunisertib plus TMZ/RTX or TMZ/RTX were: median overall survival (18.2 vs 17.9 months), median progression-free survival (7.6 vs 11.5 months), and disease control rate (80% [32/40] vs 56% [9/16] patients) respectively. PK profile of galunisertib plus TMZ/RTX regimen was consistent with previously published PK data of galunisertib. The overall safety profile across treatment arms was comparable. Conclusion No differences in efficacy, safety or pharmacokinetic variables were observed between the two treatment arms.

Biomarkers and overall survival in patients with advanced hepatocellular carcinoma treated with TGF-ßRI inhibitor galunisertib.

BACKGROUND: Transforming growth factor beta (TGF-ß) signalling is involved in the development of hepatocellular carcinoma (HCC). We followed changes in biomarkers during treatment of patients with HCC with the TGF-ßRI/ALK5 inhibitor galunisertib. METHODS: This phase 2 study (NCT01246986) enrolled second-line patients with advanced HCC into one of two cohorts of baseline serum alpha-fetoprotein (AFP): Part A (AFP ≥1.5x ULN) or Part B (AFP <1.5x ULN). Baseline and postbaseline levels of AFP, TGF-ß1, E-cadherin, selected miRNAs, and other plasma proteins were monitored. RESULTS: The study enrolled 149 patients (Part A, 109; Part B, 40). Median OS was 7.3 months in Part A and 16.8 months in Part B. Baseline AFP, TGF-ß1, E-cadherin, and an additional 16 plasma proteins (such as M-CSF, IL-6, ErbB3, ANG-2, neuropilin-1, MIP-3 alpha, KIM-1, uPA, IL-8, TIMP-1, ICAM-1, Apo A-1, CA-125, osteopontin, tetranectin, and IGFBP-1) were found to correlate with OS. In addition, a range of miRs were found to be associated with OS. In AFP responders (21% of patients in Part A with decrease of >20% from baseline) versus non-responders, median OS was 21.5 months versus 6.8 months (p = 0.0015). In TGF-ß1 responders (51% of all patients) versus non-responders, median OS was 11.2 months versus 5.3 months (p = 0.0036). CONCLUSIONS: Consistent with previous findings, both baseline levels and changes from baseline of circulating AFP and TGF-ß1 function as prognostic indicators of survival. Future trials are needed to confirm and extend these results.

Leveraging historical data into oncology development programs: Two case studies of phase 2 Bayesian augmented control trial designs.

Leveraging historical data into the design and analysis of phase 2 randomized controlled trials can improve efficiency of drug development programs. Such approaches can reduce sample size without loss of power. Potential issues arise when the current control arm is inconsistent with historical data, which may lead to biased estimates of treatment efficacy, loss of power, or inflated type 1 error. Consideration as to how to borrow historical information is important, and in particular, adjustment for prognostic factors should be considered. This paper will illustrate two motivating case studies of oncology Bayesian augmented control (BAC) trials. In the first example, a glioblastoma study, an informative prior was used for the control arm hazard rate. Sample size savings were 15% to 20% by using a BAC design. In the second example, a pancreatic cancer study, a hierarchical model borrowing method was used, which enabled the extent of borrowing to be determined by consistency of observed study data with historical studies. Supporting Bayesian analyses also adjusted for prognostic factors. Incorporating historical data via Bayesian trial design can provide sample size savings, reduce study duration, and enable a more scientific approach to development of novel therapies by avoiding excess recruitment to a control arm. Various sensitivity analyses are necessary to interpret results. Current industry efforts for data transparency have meaningful implications for access to patient-level historical data, which, while not critical, is helpful to adjust for potential imbalances in prognostic factors.

Phase II Study of the ALK5 Inhibitor Galunisertib in Very Low-, Low-, and Intermediate-Risk Myelodysplastic Syndromes.

PURPOSE: Overactivation of TGF-ß signaling is observed in myelodysplastic syndromes (MDS) and is associated with dysplastic hematopoietic differentiation. Galunisertib, a first-in-class oral inhibitor of the TGF-ß receptor type 1 kinase (ALK5) has shown effectiveness in preclinical models of MDS and acceptable toxicity in phase I studies of solid malignancies. PATIENTS AND METHODS: A phase II multicenter study of galunisertib was conducted in patients with very low-, low-, or intermediate-risk MDS by the Revised International Prognostic Scoring System criteria with hemoglobin ≤ 10.0 g/dL. Patients received oral galunisertib 150 mg twice daily for 14 days on/14 days off. RESULTS: Ten of 41 evaluable patients (24.4%; 95% confidence interval, 12.4-40.3) achieved hematologic improvement erythroid response by International Working Group (IWG) 2006 criteria. A total of 18 of 41 patients (43.9%) achieved erythroid response as per IWG 2000 criteria. Nine of 28 (32.1%) of transfusion-dependent patients had hematologic improvement. A total of 18 of 41 (44%) patients had a significant reduction in fatigue. Overall median duration of response was 90 days in all patients. Rigorous stem and progenitor flow cytometry showed that patients with an early stem cell differentiation block were more likely to respond to galunisertib. The most common treatment-emergent adverse events were grade 1 or 2 in 20 (49%) of 41 patients, including any-grade fatigue (8/41, 20%), diarrhea (7/41, 17%), pyrexia (5/41, 12%), and vomiting (5/41, 12%). CONCLUSIONS: In summary, galunisertib treatment has an acceptable safety profile and was associated with hematologic improvements in lower- and intermediate-risk MDS, with responses in heavily transfusion-dependent patients and in those with signs of an early stem cell differentiation block.

Population pharmacokinetics and exposure-overall survival analysis of the transforming growth factor-ß inhibitor galunisertib in patients with pancreatic cancer.

PURPOSE: To evaluate the exposure-overall survival (OS) relationship in patients with advanced pancreatic cancer treated with galunisertib plus gemcitabine (GG) or gemcitabine plus placebo (GP). METHODS: Galunisertib 300 mg/day was given orally as intermittent dosing and gemcitabine as per label. Galunisertib exposure metrics for each patient in the GG arm (n = 99) of a phase 2 study of pancreatic cancer were calculated. Parametric survival models were used to identify influential baseline and response covariates on OS. RESULTS: The population pharmacokinetics dataset included data from 297 patients/healthy subjects (age: 22-84 years, weight: 39-126 kg) across multiple studies, including this pancreatic cancer study. Galunisertib was rapidly absorbed with peak concentrations attained within 0.5-2 h and had an elimination half-life of 8 h. Between-subject variance on apparent clearance was estimated to be 47%. Age was the only characteristic to have a statistically significant effect on apparent clearance. A parametric Weibull survival model with treatment effect (dose) estimated a hazard ratio of 0.796, after adjusting for patient baseline factors that were significantly associated with OS. There was also a flat daily exposure-OS relationship within the observed exposure range, once all significant baseline covariates were included. Response covariates, such as reduction in CA19-9, time on treatment, and cumulative exposure over treatment cycles were also identified as significant factors for OS for patients with pancreatic cancer. CONCLUSIONS: This analysis suggests that 300 mg/day galunisertib administered as 150 mg twice daily for 14 days on/14 days off treatment is an appropriate dosing regimen for patients with pancreatic cancer.

Novel transforming growth factor beta receptor I kinase inhibitor galunisertib (LY2157299) in advanced hepatocellular carcinoma.

BACKGROUND AND AIMS: We assessed the activity of galunisertib, a small molecule inhibitor of the transforming growth factor beta (TGF-ß1) receptor I, in second-line patients with hepatocellular carcinoma (HCC) in two cohorts of baseline serum alpha fetoprotein (AFP). METHODS: Patients with advanced HCC who progressed on or were ineligible to receive sorafenib, Child-Pugh A/B7 and ECOG PS ≤1 were enrolled into Part A (AFP ≥ 1.5× ULN) or Part B (AFP < 1.5× ULN). Patients were treated with 80 or 150 mg galunisertib BID for 14 days per 28-day cycle. Endpoints were time-to-progression (TTP) and changes in circulating AFP and TGF-ß1 levels, as well as safety, pharmacokinetics, progression-free survival and overall survival (OS). RESULTS: Patients (n = 149) were enrolled with median age 65 years. Median TTP was 2.7 months (95% CI: 1.5-2.9) in Part A (n = 109) and 4.2 months (95% CI: 1.7-5.5) in Part B (n = 40). Median OS was 7.3 months (95% CI: 4.9-10.5) in Part A and 16.8 months (95% CI: 10.5-24.4) in Part B. OS was longer in AFP responders (>20% decrease from baseline, Part A) compared to non-responders (21.5 months vs 6.8 months). OS was longer in TGF-ß1 responders (>20% decrease from baseline, all patients) compared to non-responders. The most common Grade 3/4 treatment-related adverse events were neutropenia (n = 4) and fatigue, anaemia, increased bilirubin, hypoalbuminemia and embolism (each, n = 2). CONCLUSIONS: Galunisertib treatment had a manageable safety profile in patients with HCC. Lower baseline AFP and a response in AFP or TGF-ß1 levels (vs no response) correlated with longer survival. TRIAL REGISTRATION NUMBER: NCT01246986 at ClinicalTrials.gov.