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Purpose:Sabatolimab (MBG453) and spartalizumab are mAbs that bind T-cell immunoglobulin domain and mucin domain-3 (TIM-3) and programmed death-1 (PD-1), respectively. This phase I/II study evaluated the safety and efficacy of sabatolimab, with or without spartalizumab, in patients with advanced solid tumors.Patients and Methods:Primary objectives of the phase I/Ib part were to characterize the safety and estimate recommended phase II dose (RP2D) for future studies. Dose escalation was guided by a Bayesian (hierarchical) logistic regression model. Sabatolimab was administered intravenously, 20 to 1,200 mg, every 2 or 4 weeks (Q2W or Q4W). Spartalizumab was administered intravenously, 80 to 400 mg, Q2W or Q4W.Results:Enrolled patients (n = 219) had a range of cancers, most commonly ovarian (17%) and colorectal cancer (7%); patients received sabatolimab (n = 133) or sabatolimab plus spartalizumab (n = 86). The MTD was not reached. The most common adverse event suspected to be treatment-related was fatigue (9%, sabatolimab; 15%, combination). No responses were seen with sabatolimab. Five patients receiving combination treatment had partial responses (6%; lasting 12–27 months) in colorectal cancer (n = 2), non–small cell lung cancer (NSCLC), malignant perianal melanoma, and SCLC. Of the five, two patients had elevated expression of immune markers in baseline biopsies; another three had >10% TIM-3–positive staining, including one patient with NSCLC who received prior PD-1 therapy.Conclusions:Sabatolimab plus spartalizumab was well tolerated and showed preliminary signs of antitumor activity. The RP2D for sabatolimab was selected as 800 mg Q4W (alternatively Q3W or Q2W schedules, based on modeling), with or without 400 mg spartalizumab Q4W.

Supplementary Materials

Purpose:Sabatolimab (MBG453) and spartalizumab are mAbs that bind T-cell immunoglobulin domain and mucin domain-3 (TIM-3) and programmed death-1 (PD-1), respectively. This phase I/II study evaluated the safety and efficacy of sabatolimab, with or without spartalizumab, in patients with advanced solid tumors.Patients and Methods:Primary objectives of the phase I/Ib part were to characterize the safety and estimate recommended phase II dose (RP2D) for future studies. Dose escalation was guided by a Bayesian (hierarchical) logistic regression model. Sabatolimab was administered intravenously, 20 to 1,200 mg, every 2 or 4 weeks (Q2W or Q4W). Spartalizumab was administered intravenously, 80 to 400 mg, Q2W or Q4W.Results:Enrolled patients (n = 219) had a range of cancers, most commonly ovarian (17%) and colorectal cancer (7%); patients received sabatolimab (n = 133) or sabatolimab plus spartalizumab (n = 86). The MTD was not reached. The most common adverse event suspected to be treatment-related was fatigue (9%, sabatolimab; 15%, combination). No responses were seen with sabatolimab. Five patients receiving combination treatment had partial responses (6%; lasting 12–27 months) in colorectal cancer (n = 2), non–small cell lung cancer (NSCLC), malignant perianal melanoma, and SCLC. Of the five, two patients had elevated expression of immune markers in baseline biopsies; another three had >10% TIM-3–positive staining, including one patient with NSCLC who received prior PD-1 therapy.Conclusions:Sabatolimab plus spartalizumab was well tolerated and showed preliminary signs of antitumor activity. The RP2D for sabatolimab was selected as 800 mg Q4W (alternatively Q3W or Q2W schedules, based on modeling), with or without 400 mg spartalizumab Q4W.

Background MBG453 and spartalizumab are humanized IgG4 mAbs that block binding of TIM-3 to PtdSer and PD-1 to PD-L1/2, respectively. In Ph I dose escalation, MBG453 + spartalizumab showed preliminary antitumor activity in advanced solid tumors. Here we report Ph II MBG453 + spartalizumab dose expansion in pts with NSCLC and melanoma (NCT02608268). Methods Pts with melanoma or NSCLC who had progressive disease (PD) on/after anti–PD-1/L1 therapy received MBG453 (800 mg, Q4W) + spartalizumab (400 mg, Q4W) until unacceptable toxicity, PD, or investigator/pt decision. On prior anti–PD-1/L1 therapy clinical benefit (CB) was defined as durable (DCB) if pts had a complete or partial response, or stable disease (SD) for ≥6 months, or non-durable (NDCB) if pts had SD for Results As of Feb 15, 2019, 33 pts received MBG453 + spartalizumab (melanoma: n = 16; NSCLC: n = 17); 5 (15.2%) pts were ongoing (melanoma: n = 3 [18.8%]; NSCLC: n = 2 [11.8%]); 28 (84.8%) pts discontinued, mainly due to PD (60.6%) and death due to underlying disease (12.1%). Anti–PD-1/L1 was the last therapy before enrollment in 21 (63.6%) pts (melanoma: n = 10 [62.5%]; NSCLC: n = 11 [64.7%]). On prior anti–PD-1/L1 therapy, 6 (37.5%) melanoma and 7 (41.2%) NSCLC pts had DCB and 10 (62.5%) melanoma and 9 (52.9%) NSCLC pts had NDCB; CB was unknown (UNK) in 1 NSCLC pt. On MBG453 + spartalizumab, 3/16 (18.8%) melanoma pts (prior anti-PD-1/L1: DCB n = 2; NDCB n = 1) and 7/17 (41.2%) NSCLC pts (prior anti-PD-1/L1: DCB n = 3; NDCB n = 3; UNK n = 1) had SD per RECIST 1.1. Baseline tumor PD-L1 appears higher in pts with SD vs PD. Data suggest a trend of inverse association between tumor reduction and CD163 tumor expression. Common treatment-related adverse events (TRAEs) were fatigue, nausea, and pruritus (n = 3 each [9.1%]); 0 melanoma and 2 (11.8%) NSCLC pts (pruritus, amylase, lipase, and increased ALT) had Grade 3/4 TRAEs. Conclusions MBG453 (800 mg, Q4W) + spartalizumab (400 mg, Q4W) was well tolerated but with limited efficacy in pts with melanoma and NSCLC who had PD on/after prior anti–PD-1/L1 therapy. Further evaluation of MBG453 in other indications/combinations is needed to assess the clinical relevance of TIM-3 inhibition. Editorial acknowledgement Jenny Winstanley, PhD, of Articulate Science Ltd. Legal entity responsible for the study Novartis Pharmaceuticals. Funding Novartis Pharmaceuticals. Disclosure G. Curigliano: Honoraria (self), Advisory Board: Novartis; Honoraria (self), Advisory Board: Roche; Speaker Bureau / Expert testimony, Expert talk: Pfizer; Speaker Bureau / Expert testimony, Expert talk: Eli Lilly; Advisory / Consultancy, Scientific consultation: Ellipsis. A. Santoro: Speaker Bureau / Expert testimony: Takeda; Advisory / Consultancy, Speaker Bureau / Expert testimony: BMS; Speaker Bureau / Expert testimony: Roche; Speaker Bureau / Expert testimony: AbbVie; Speaker Bureau / Expert testimony: Amgen; Speaker Bureau / Expert testimony: Celgene; Advisory / Consultancy, Speaker Bureau / Expert testimony: Servier; Advisory / Consultancy, Speaker Bureau / Expert testimony: Gilead; Speaker Bureau / Expert testimony: AstraZencea; Advisory / Consultancy, Speaker Bureau / Expert testimony: Pfizer; Advisory / Consultancy, Speaker Bureau / Expert testimony: Arquile; Speaker Bureau / Expert testimony: Lilly; Speaker Bureau / Expert testimony: Sandoz; Advisory / Consultancy, Speaker Bureau / Expert testimony: Eisai; Speaker Bureau / Expert testimony: Novartis; Advisory / Consultancy, Speaker Bureau / Expert testimony: Bayer; Advisory / Consultancy, Speaker Bureau / Expert testimony: MSD. D. Kim: Research grant / Funding (institution): Alpha Biopharm; Research grant / Funding (institution): AstraZeneca/MedImmune; Research grant / Funding (institution): Hanmi; Research grant / Funding (institution): Janssen; Research grant / Funding (institution): Merus; Research grant / Funding (institution): Mirati Therapeutics; Research grant / Funding (institution): MSD; Research grant / Funding (institution): Novartis; Research grant / Funding (institution): ONO Pharmaceutical; Research grant / Funding (institution): Pfizer; Research grant / Funding (institution): Roche/Genentech; Research grant / Funding (institution): Takeda; Research grant / Funding (institution): TP Therapeutics; Research grant / Funding (institution): Xcovery; Research grant / Funding (institution): Yuhan. S. Hodi: Honoraria (self), Advisory / Consultancy, Research grant / Funding (institution): Bristol Mysers Squibb; Advisory / Consultancy: Merck; Advisory / Consultancy: EMD Serono; Advisory / Consultancy, Research grant / Funding (institution): Novartis; Advisory / Consultancy: Takeda; Advisory / Consultancy: Surface; Advisory / Consultancy: Genentech/Roche; Advisory / Consultancy: Compass Therapeutics; Advisory / Consultancy: Apricity; Advisory / Consultancy: Bayer; Advisory / Consultancy: Aduro; Advisory / Consultancy: Partners Therapeutics; Advisory / Consultancy: Sanofi; Advisory / Consultancy: Pfizer; Advisory / Consultancy: Pionyr; Advisory / Consultancy: 7 Hills Pharma; Advisory / Consultancy: Verastem; Advisory / Consultancy: Torque; Advisory / Consultancy: Rheos. T. Doi: Research grant / Funding (institution): Lilly ; Research grant / Funding (institution): Taiho; Research grant / Funding (institution): Novartis; Research grant / Funding (institution): Merck Serono; Research grant / Funding (institution): MSD; Research grant / Funding (institution): Boehringer Ingelheim ; Research grant / Funding (institution): Quintiles; Research grant / Funding (institution): Pfizer; Advisory / Consultancy, Research grant / Funding (institution): Dainippon Sumitomo; Research grant / Funding (institution): Kyowa Hakko Kirin; Advisory / Consultancy, Research grant / Funding (institution): Daiichi Sankyo; Research grant / Funding (institution): BMS; Advisory / Consultancy, Research grant / Funding (institution): AbbVie; Advisory / Consultancy, Research grant / Funding (institution): Takeda; Advisory / Consultancy: Otsuka. T. Longmire: Full / Part-time employment: Novartis. H. Sun: Full / Part-time employment: Novartis. A. Xyrafas: Full / Part-time employment: Novartis. S. Gutzwiller: Shareholder / Stockholder / Stock options, Full / Part-time employment: Novartis. L. Manenti: Shareholder / Stockholder / Stock options, Full / Part-time employment: Novartis. All other authors have declared no conflicts of interest.

Metallothioneins are proteins that are involved in intracellular zinc storage and transport. Their expression levels have been reported to be elevated in several settings of skeletal muscle atrophy. We therefore investigated the effect of metallothionein blockade on skeletal muscle anabolism in vitro and in vivo. We found that concomitant abrogation of metallothioneins 1 and 2 results in activation of the Akt pathway and increases in myotube size, in type IIb fiber hypertrophy, and ultimately in muscle strength. Importantly, the beneficial effects of metallothionein blockade on muscle mass and function was also observed in the setting of glucocorticoid addition, which is a strong atrophy-inducing stimulus. Given the blockade of atrophy and the preservation of strength in atrophy-inducing settings, these results suggest that blockade of metallothioneins 1 and 2 constitutes a promising approach for the treatment of conditions which result in muscle atrophy.

Brown adipose tissue (BAT) is a key tissue for energy expenditure via fat and glucose oxidation for thermogenesis. In this study, we demonstrate that the myostatin/activin receptor IIB (ActRIIB) pathway, which serves as an important negative regulator of muscle growth, is also a negative regulator of brown adipocyte differentiation. In parallel to the anticipated hypertrophy of skeletal muscle, the pharmacological inhibition of ActRIIB in mice, using a neutralizing antibody, increases the amount of BAT without directly affecting white adipose tissue. Mechanistically, inhibition of ActRIIB inhibits Smad3 signaling and activates the expression of myoglobin and PGC-1 coregulators in brown adipocytes. Consequently, ActRIIB blockade in brown adipose tissue enhances mitochondrial function and uncoupled respiration, translating into beneficial functional consequences, including enhanced cold tolerance and increased energy expenditure. Importantly, ActRIIB inhibition enhanced energy expenditure only at ambient temperature or in the cold and not at thermoneutrality, where nonshivering thermogenesis is minimal, strongly suggesting that brown fat activation plays a prominent role in the metabolic actions of ActRIIB inhibition.

The importance of insulin-like growth factor I (IGF-I) on maintenance of skeletal integrity has been widely recognized. Although osteoblasts secrete some IGF-I, the liver is the primary endocrine source for IGF-I. We have studied the regulation of the human IGF-I promoter in the hepatocyte cell line Hep3B, and we have shown that the IGF-I promoter, when co-transfected in Hep3B cells together with an estrogen receptor (ER)-alpha expression vector, was transcriptionally regulated by raloxifene or raloxifene-like molecules but not by 17beta-estradiol and 4(OH)-tamoxifen. The induction mediated by raloxifene is antagonized by 17beta-estradiol and mediated selectively by ER-alpha, but not by ER-beta. Transfer of IGF-I promoter sequences from -733 to -65 or from -375 to -65 to a minimal Fos promoter resulted in a comparable responsiveness to raloxifene. This region contains two CAAT/enhancer-binding protein sites and an activator protein 1 site, both of which have been shown to be involved in estrogen receptor-mediated transactivation. When the CAAT/enhancer-binding protein sites were mutated in a construct bearing the sequence from -375 to -65 in front of the minimal Fos promoter, raloxifene induction was reduced, whereas mutation of the other elements did not affect induction. In addition, using chimeric proteins, we delineated the domains of ER-alpha that confer to ER-alpha transactivation abilities on the IGF-I promoter that are not exhibited by ER-beta. These data shed new light on the mechanism of action of antiestrogens and might help explain, at least in part, the bone-protective effects observed for some antiestrogens in ovariectomized animals.

Molecular mechanisms underlying sarcopenia, the age-related loss of skeletal muscle mass and function, remain unclear. To identify molecular changes that correlated best with sarcopenia and might contribute to its pathogenesis, we determined global gene expression profiles in muscles of rats aged 6, 12, 18, 21, 24, and 27 months. These rats exhibit sarcopenia beginning at 21 months. Correlation of the gene expression versus muscle mass or age changes, and functional annotation analysis identified gene signatures of sarcopenia distinct from gene signatures of aging. Specifically, mitochondrial energy metabolism (e.g., tricarboxylic acid cycle and oxidative phosphorylation) pathway genes were the most downregulated and most significantly correlated with sarcopenia. Also, perturbed were genes/pathways associated with neuromuscular junction patency (providing molecular evidence of sarcopenia-related functional denervation and neuromuscular junction remodeling), protein degradation, and inflammation. Proteomic analysis of samples at 6, 18, and 27 months confirmed the depletion of mitochondrial energy metabolism proteins and neuromuscular junction proteins. Together, these findings suggest that therapeutic approaches that simultaneously stimulate mitochondrogenesis and reduce muscle proteolysis and inflammation have potential for treating sarcopenia.

Runx2 is a master regulator of bone development and has also been described as an oncogene. Estrogen Receptor α (ERα) and Estrogen Related Receptor α (ERRα), both implicated in bone metabolism and breast cancer, have been shown to share common transcriptional targets. Here, we show that ERα is a positive regulator of Runx2-I transcription. Moreover, ERRα can act as a transcriptional activator of Runx2-I in presence of peroxisome proliferator activated receptor gamma coactivator-1 alpha (PGC-1α). In contrast, ERRα behaves as a negative regulator of Runx2-I transcription in presence of PGC-1β. ERα and ERRα cross-talk via a common estrogen receptor response element on the Runx2-I promoter. In addition, estrogen regulates PGC-1β that in turn is able to modulate both ERα and ERRα transcriptional activity.

The nuclear orphan receptor human estrogen receptor-related receptor (ERR)-α is implicated in bone metabolism. We studied the effect of ERRα silencing in human mesenchymal stem cells (hMSCs) during osteoblastogenesis. We found that ERRα silencing led to an increase of bone sialoprotein and a decrease of osteopontin mRNA levels, suggesting enhanced osteoblastic differentiation. This was confirmed by an increased ability of hMSCs to deposit calcium. Concomitantly, knockdown of ERRα inhibited adipogenesis, resulting in a decrease in adipocyte number and adipocyte marker gene expression. In line with a negative role of ERRα in bone metabolism, we found that adult female and male ERRα-deficient mice displayed a moderate increase in femoral cancellous bone volume and density. Osteoblast surface was increased and marrow fat volume decreased in these animals. Furthermore, ERRα-deficient osteoblasts displayed increased differentiation properties in vitro in line with our observations in hMSCs. In summary, we identified a role for ERRα in bone mass regulation by affecting osteoblastic differentiation.

Angiogenesis is a fundamental process in skeletal development and repair, and previous studies indicate that vascular endothelial growth factor (VEGF), an endothelial cell-specific angiogenic factor, may be involved in bone formation and repair. Therefore, we studied the hormonal regulation of VEGF expression in SaOS-2 osteoblast-like cells, both at the protein level, and at the transcriptional level by transient transfection experiments. 1,25-Dihydroxyvitamin D3 [1,25-(OH)2D3], increased VEGF expression by approximately 3-fold, and the increase was dose dependent, with maximum stimulation between 1.0 and 10 nM of 1,25-(OH)2D3. Up-regulation of VEGF protein was detected already after 6 h of treatment. VEGF up-regulation was also observed in ROS-17/2.8 and OHS-4 osteoblast-like cells but not in MCF-7 and MDA-MB231 breast carcinoma cells. Dexamethasone (Dex) decreased VEGF expression to 40% of the control, but when added together with 1,25-(OH)2D3, had no effects on the up-regulation of VEGF by 1,25-(OH)2D3. PTH1-34 stimulated weakly VEGF expression, but combined with 1,25-(OH)2D3, resulted in a close to 5-fold stimulation. A 4-day pretreatment of the cells with Dex increased the vitamin D3 receptor expression and resulted in a stronger stimulation of VEGF by 1,25-(OH)2D3, alone or in combination with PTH1-34. The results show that the VEGF promoter is a target of 1,25-(OH)2D3 regulation in osteoblasts, despite the lack of classical vitamin D3 responsive elements. The up-regulation of VEGF in osteoblast-like cells by calciotropic hormones provides additional evidence of the involvement of VEGF in bone metabolism.