BackgroundTGFβ signaling plays a pleotropic role in tumor biology, promoting tumor proliferation, invasion and metastasis, and escape from immune surveillance. Inhibiting TGFβ’s immune suppressive effects has become of particular interest as a way to increase the benefit of cancer immunotherapy. Here we utilized preclinical models to explore the impact of the clinical stage TGFβ pathway inhibitor, galunisertib, on anti-tumor immunity at clinically relevant doses.ResultsIn vitro treatment with galunisertib reversed TGFβ and regulatory T cell mediated suppression of human T cell proliferation. In vivo treatment of mice with established 4T1-LP tumors resulted in strong dose-dependent anti-tumor activity with close to 100% inhibition of tumor growth and complete regressions upon cessation of treatment in 50% of animals. This effect was CD8+ T cell dependent, and led to increased T cell numbers in treated tumors. Mice with durable regressions rejected tumor rechallenge, demonstrating the establishment of immunological memory. Consequently, mice that rejected immunogenic 4T1-LP tumors were able to resist rechallenge with poorly immunogenic 4 T1 parental cells, suggesting the development of a secondary immune response via antigen spreading as a consequence of effective tumor targeting. Combination of galunisertib with PD-L1 blockade resulted in improved tumor growth inhibition and complete regressions in colon carcinoma models, demonstrating the potential synergy when cotargeting TGFβ and PD-1/PD-L1 pathways. Combination therapy was associated with enhanced anti-tumor immune related gene expression profile that was accelerated compared to anti-PD-L1 monotherapy.ConclusionsTogether these data highlight the ability of galunisertib to modulate T cell immunity and the therapeutic potential of combining galunisertib with current PD-1/L1 immunotherapy.

Background: Futibatinib is an oral, irreversible, highly selective fibroblast growth factor receptor (FGFR)1e4 inhibitor with potent preclinical activity against tumors harboring FGFR aberrations. This first-in-human, phase I dose-escalation trial (NCT02052778) evaluates the safety and pharmacokinetics/pharmacodynamics of futibatinib in advanced solid tumors. Patients and methods: Following a standard 3þ3 dose-escalation design, eligible patients with advanced solid tumors refractory to standard therapies received 8e200 mg futibatinib three times a week (t.i.w.) or 4e24 mg once daily (q.d.). Results: A total of 86 patients were enrolled in the nine t.i.w. (n ¼ 42) and five q.d. cohorts (n ¼ 44); 71 patients (83%) had tumors harboring FGF/FGFR aberrations. Three of nine patients in the 24-mg q.d. cohort experienced dose-limiting toxicities, including grade 3 increases in alanine transaminase, aspartate transaminase, and blood bilirubin (n ¼ 1 each). The maximum tolerated dose (MTD) was determined to be 20 mg q.d.; no MTD was defined for the t.i.w. schedule. Across cohorts (n ¼ 86), the most common treatment-emergent adverse events (TEAEs) were hyperphosphatemia (59%), diarrhea (37%), and constipation (34%); 48% experienced grade 3 TEAEs. TEAEs led to dose interruptions, dose reductions, and treatment discontinuations in 55%, 14%, and 3% of patients, respectively. Pharmacokinetics were dose proportional across all q.d. doses but not all t.i.w. doses evaluated, with saturation observed between 80 and 200 mg t.i.w. Serum phosphorus increased dose dependently with futibatinib on both schedules, but a stronger exposureeresponse relationship was observed with q.d. dosing, supporting 20 mg q.d. as the recommended phase II dose (RP2D). Overall, partial responses were observed in five patients [FGFR2 fusion-positive intrahepatic cholangiocarcinoma (n ¼ 3) and FGFR1-mutant primary brain tumor (n ¼ 2)], and stable disease in 41 (48%). Conclusions: Futibatinib treatment resulted in manageable safety, pharmacodynamic activity, and preliminary responses in patients with advanced solid tumors. The results of this phase I dose-escalation trial support 20 mg q.d. futibatinib as the RP2D. Clinical trial registration: FOENIX-101 (ClinicalTrials.gov, NCT02052778).

Therapeutics, Novartis, Pfizer, PUMA Biotechnology, Seattle Genetics, Taiho Pharmaceutical, Zymeworks, outside of the submitted work. R. Bahleda does not have conflicts of interests to disclose. C. Hierro reports grants from Bayer and Merck, has served on the speaker bureau for Merck Sharp & Dohme, and has received travel expenses from Amgen and Merck. M. Sanson reports research support from AstraZeneca, has served on the data and safety monitoring board for Genenta, has served on the advisory board on Abbvie, and has received travel expenses from Abbvie. J. Bridgewater reports advisory board fees from Taiho Pharmaceuticals, outside the submitted work. H-T. Arkenau is an investigator in studies sponsored by Taiho and reports an advisory role in Guardant, Roche, and Servier. B. Tran has served in an advisory role at

Background Galunisertib is the first-in-class, first-in-human, oral small-molecule type I transforming growth factor-beta receptor (ALK5) serine/threonine kinase inhibitor to enter clinical development. The effect of galunisertib vs. placebo in patients with unresectable pancreatic cancer was determined. Methods This was a two-part, multinational study: phase 1b was a non-randomised, open-label, multicentre, and dose-escalation study; phase 2 was a randomised, placebo- and Bayesian-augmented controlled, double-blind study in patients with locally advanced or metastatic pancreatic adenocarcinoma considered candidates for first-line chemotherapy with gemcitabine. Patients were randomised 2:1 to galunisertib–gemcitabine ( N = 104) or placebo-gemcitabine ( N = 52). Gemcitabine dose was 1000 mg/m 2 QW. Primary endpoints for phases 1b and 2, respectively, were phase 2 dose and overall survival. Secondary objectives included tolerability and biomarkers. Results Dose-escalation suggested a 300-mg/day dose. Primary objective was met: median survival times were 8.9 and 7.1 months for galunisertib and placebo, respectively (hazard ratio [HR] = 0.79 [95% credible interval: 0.59–1.09] and posterior probability HR < 1 = 0.93). Lower baseline biomarkers macrophage inflammatory protein-1-alpha and interferon-gamma-induced protein 10 were associated with galunisertib benefit. Conclusions Galunisertib–gemcitabine combination improved overall survival vs. gemcitabine in patients with unresectable pancreatic cancer, with minimal added toxicity. Future exploration of galunisertib in pancreatic cancer is ongoing in combination with durvalumab.

INTRODUCTION: Inhibition of tumor growth factor-β (TGF-β) receptor type I potentiated the activity of sorafenib in preclinical models of hepatocellular carcinoma (HCC). Galunisertib is a small-molecule selective inhibitor of TGF-β1 receptor type I, which demonstrated activity in a phase 2 trial as second-line HCC treatment. METHODS: The combination of galunisertib and sorafenib (400 mg BID) was tested in patients with advanced HCC and Child-Pugh A liver function without prior systemic therapy. Galunisertib dose was administered 80 or 150 mg b.i.d. orally for 14 days every 28 days in safety lead-in cohorts; in the expansion cohort, all patients received galunisertib 150 mg b.i.d. Objectives included time-to-tumor progression, changes in circulating alpha fetoprotein and TGF-β1, safety, overall survival (OS), response rate, and pharmacokinetics (PK). RESULTS: Patients (n = 47) were enrolled from 5 non-Asian countries; 3 and 44 patients received the 80 mg and 150 mg b.i.d. doses of galunisertib, respectively. The pharmacokinetics and safety profiles were consistent with monotherapy of each drug. For the 150 mg b.i.d. galunisertib cohort, the median time-to-tumor progression was 4.1 months; the median OS was 18.8 months. A partial response was seen in 2 patients, stable disease in 21, and progressive disease in 13. TGF-β1 responders (decrease of >20% from baseline) vs nonresponders had longer OS (22.8 vs 12.0 months, P = 0.038). DISCUSSION: The combination of galunisertib and sorafenib showed acceptable safety and a prolonged OS outcome.