Phase II study of talazoparib in advanced cancers with BRCA1/2, DNA repair, and PTEN alterations.

Cancer cells with BRCA1/2 deficiencies are sensitive to poly (ADP-ribose) polymerase (PARP) inhibitors. We evaluated the efficacy of talazoparib in DNA-Damage Repair (DDR)-altered patients. In this phase II trial, patients were enrolled onto one of four cohorts based on molecular alterations: (1) somatic BRCA1/2, (2) other homologous recombination repair pathway, (3) PTEN and (4) germline BRCA1/2. The primary endpoint was a clinical benefit rate (CBR): complete response, partial response or stable disease ≥24 weeks. 79 patients with a median of 4 lines of therapy were enrolled. CBR for cohorts 1-4 were: 32.5%, 19.7%, 9.4% and 30.6%, respectively. PTEN mutations correlated with reduced survival and a trend towards shorter time to progression.Talazoparib demonstrated clinical benefit in selected DDR-altered patients. PTEN mutations/loss patients derived limited clinical benefit. Further study is needed to determine whether PTEN is prognostic or predictive of response to PARP inhibitors.

ENDOLUNG trial. A phase 1/2 study of the Akt/mTOR inhibitor and autophagy inducer Ibrilatazar (ABTL0812) in combination with paclitaxel/carboplatin in patients with advanced/recurrent endometrial cancer.

BACKGROUND: Carboplatin and paclitaxel (CP) have been the standard of care for advanced/recurrent endometrial cancer (EC) for many years. However, this chemotherapy combination shows limited efficacy and recurrences often occur in less than 12 months. ABTL0812 is a novel drug that selectively kill cancer cells by cytotoxic autophagy and has shown anticancer efficacy in preclinical models of EC in combination with CP. METHODS: ENDOLUNG was an open-label, phase 1/2 clinical trial designed to determine the safety and efficacy of Ibrilatazar (ABTL0812) with CP in patients with advanced/recurrent EC and non-irradiable stage III and IV squamous non-small cell lung cancer (sq-NSCLC). The phase 1 part consisted of a 3 + 3 de-escalation design followed by an expansion cohort with 12 patients. The primary endpoint was safety. ABTL0812 starting dose was 1300 mg tid combined with carboplatin at area under the curve (AUC) 5 and paclitaxel at 175 mg/m2 both administered every 21 days for up to 8 cycles. The phase 2 part included a total of 51 patients. The primary endpoint was overall response rate (ORR) and the secondary endpoints included duration of response (DOR), progression-free survival (PFS) and overall survival (OS). RESULTS: During the phase 1 only one dose limiting toxicity (DLT), a grade 4 neutropenia, was observed in 1 out of 6 patients, thus no de-escalation was applied. One additional DLT, a grade 3 febrile neutropenia, was observed in the expansion cohort, thus the recommended phase 2 dose (RP2D) for ABTL0812 was established at 1300 mg tid. Most frequent hematological adverse events (AE) of the combination were neutropenia (52.9%), anemia (37.3%) and thrombocytopenia (19.6%). Nausea (66.7%), asthenia (66.7%), diarrhea (54.9%) and vomiting (54.9%) were the most frequent non-hematological adverse events (AEs). The combination of ABTL0812 plus CP showed an ORR of 65.8% (13.2% complete response and 52.6% partial response) with a median DOR of 7.4 months (95% CI: 6.3-10.8 months). Median PFS was 9.8 months (95% CI: 6.6-10.6) and median OS 23.6 months (95% CI 6.4-ND). Pharmacokinetic parameters were compatible with target engagement observed in preclinical studies, and blood pharmacodynamic biomarkers indicated sustained target regulation during, at least, 28 days after starting the treatment. CONCLUSIONS: This study suggests that the combination of ABTL0812 with CP is safe and feasible with an encouraging activity in patients with advanced/recurrent EC. Our data warrant further confirmation in prospective randomized trials. TRIAL REGISTRATION: EU Clinical Trial Register, EudraCT number 2016-001352-21 and National Clinical Trials Number, NCT03366480. Registration on 19 September 2016.

Metastatic extraneural glioblastoma diagnosed with molecular testing.

Glioblastoma, the most common malignant brain tumor in adults, is associated with a median overall survival duration of less than 2 years. Extraneural metastases occur in less than 1% of all patients with glioblastoma. The mechanism of extraneural metastasis is unclear. We present a case of extensive extraneural, extraosseous, epidural, and soft-tissue metastasis of glioblastoma. The diagnosis of metastatic glioblastoma was made only after next-generation sequencing (NGS) of the metastatic paraspinal lesions was completed. The CDK4, pTERT, PTEN, and TP53 molecular alterations seen in the initial intracranial glioblastoma were found in the paraspinal tumor, along with the addition of MYC, which is implicated in angiogenesis and epidermal-to-mesenchymal transition. Immunohistochemical stains showed that neoplastic cells were negative for GFAP. In conclusion, this case raises awareness about the role of NGS in the diagnosis of extraneural glioblastoma. This diagnosis was not possible with histology alone and only became evident after molecular profiling of the metastatic lesions and its comparison to the original tumor.

A Phase II Trial of the WEE1 Inhibitor Adavosertib in SETD2-Altered Advanced Solid Tumor Malignancies (NCI 10170).

We sought to evaluate the efficacy of WEE1 inhibitor adavosertib in patients with solid tumor malignancies (cohort A) and clear cell renal cell carcinoma (ccRCC; cohort B). NCT03284385 was a parallel cohort, Simon two-stage, phase II study of adavosertib (300 mg QDAY by mouth on days 1-5 and 8-12 of each 21-day cycle) in patients with solid tumor malignancies harboring a pathogenic SETD2 mutation. The primary endpoint was the objective response rate. Correlative assays evaluated the loss of H3K36me3 by IHC, a downstream consequence of SETD2 loss, in archival tumor tissue. Eighteen patients were enrolled (9/cohort). The median age was 60 years (range 45-74). The median duration of treatment was 1.28 months (range 0-24+). No objective responses were observed in either cohort; accrual was halted following stage 1. Minor tumor regressions were observed in 4/18 (22%) evaluable patients. Stable disease (SD) was the best overall response in 10/18 (56%) patients, including three patients with SD > 4 months. One patient with ccRCC remains on treatment for >24 months. The most common adverse events of any grade were nausea (59%), anemia (41%), diarrhea (41%), and neutropenia (41%). Nine patients (50%) experienced a Grade ≥3 adverse event. Of eight evaluable archival tissue samples, six (75%) had a loss of H3K36me3 by IHC. Adavosertib failed to exhibit objective responses in SETD2-altered ccRCC and other solid tumor malignancies although prolonged SD was observed in a subset of patients. Combination approaches may yield greater depth of tumor response. SIGNIFICANCE: WEE1 inhibition with adavosertib monotherapy demonstrated limited clinical activity in patients with SETD2-altered solid tumors despite compelling preclinical data indicating a synthetic lethal effect, which did not translate into robust tumor regression. Loss of the H3K36me3 trimethylation mark caused by SETD2-deficiency was confirmed in the majority of evaluable tumors. A subset of patients derived clinical benefit as manifested by minor tumor regressions and prolonged SD.

Pemigatinib in previously treated solid tumors with activating FGFR1-FGFR3 alterations: phase 2 FIGHT-207 basket trial.

Fibroblast growth factor receptor (FGFR) alterations drive oncogenesis in multiple tumor types. Here we studied pemigatinib, a selective, potent, oral FGFR1-FGFR3 inhibitor, in the phase 2 FIGHT-207 basket study of FGFR-altered advanced solid tumors. Primary end points were objective response rate (ORR) in cohorts A (fusions/rearrangements, n = 49) and B (activating non-kinase domain mutations, n = 32). Secondary end points were progression-free survival, duration of response and overall survival in cohorts A and B, and safety. Exploratory end points included ORR of cohort C (kinase domain mutations, potentially pathogenic variants of unknown significance, n = 26) and analysis of co-alterations associated with resistance and response. ORRs for cohorts A, B and C were 26.5% (13/49), 9.4% (3/32) and 3.8% (1/26), respectively. Tumors with no approved FGFR inhibitors or those with alterations not previously confirmed to be sensitive to FGFR inhibition had objective responses. In cohorts A and B, the median progression-free survival was 4.5 and 3.7 months, median duration of response was 7.8 and 6.9 months and median overall survival was 17.5 and 11.4 months, respectively. Safety was consistent with previous reports. The most common any-grade treatment-emergent adverse events were hyperphosphatemia (84%) and stomatitis (53%). TP53 co-mutations were associated with lack of response and BAP1 alterations with higher response rates. FGFR1-FGFR3 gatekeeper and molecular brake mutations led to acquired resistance. New therapeutic areas for FGFR inhibition and drug failure mechanisms were identified across tumor types. ClinicalTrials.gov identifier: NCT03822117 .

A risk analysis of alpelisib-induced hyperglycemia in patients with advanced solid tumors and breast cancer.

BACKGROUND: Hyperglycemia is an on-target effect of PI3Kα inhibitors. Early identification and intervention of treatment-induced hyperglycemia is important for improving management of patients receiving a PI3Kα inhibitor like alpelisib. Here, we characterize incidence of grade 3/4 alpelisib-related hyperglycemia, along with time to event, management, and outcomes using a machine learning model. METHODS: Data for the risk model were pooled from patients receiving alpelisib ± fulvestrant in the open-label, phase 1 X2101 trial and the randomized, double-blind, phase 3 SOLAR-1 trial. The pooled population (n = 505) included patients with advanced solid tumors (X2101, n = 221) or HR+/HER2- advanced breast cancer (SOLAR-1, n = 284). External validation was performed using BYLieve trial patient data (n = 340). Hyperglycemia incidence and management were analyzed for SOLAR-1. RESULTS: A random forest model identified 5 baseline characteristics most associated with risk of developing grade 3/4 hyperglycemia (fasting plasma glucose, body mass index, HbA1c, monocytes, age). This model was used to derive a score to classify patients as high or low risk for developing grade 3/4 hyperglycemia. Applying the model to patients treated with alpelisib and fulvestrant in SOLAR-1 showed higher incidence of hyperglycemia (all grade and grade 3/4), increased use of antihyperglycemic medications, and more discontinuations due to hyperglycemia (16.7% vs. 2.6% of discontinuations) in the high- versus low-risk group. Among patients in SOLAR-1 (alpelisib + fulvestrant arm) with PIK3CA mutations, median progression-free survival was similar between the high- and low-risk groups (11.0 vs. 10.9 months). For external validation, the model was applied to the BYLieve trial, for which successful classification into high- and low-risk groups with shorter time to grade 3/4 hyperglycemia in the high-risk group was observed. CONCLUSIONS: A risk model using 5 clinically relevant baseline characteristics was able to identify patients at higher or lower probability for developing alpelisib-induced hyperglycemia. Early identification of patients who may be at higher risk for hyperglycemia may improve management (including monitoring and early intervention) and potentially lead to improved outcomes. REGISTRATION: ClinicalTrials.gov: NCT01219699 (registration date: October 13, 2010; retrospectively registered), ClinicalTrials.gov: NCT02437318 (registration date: May 7, 2015); ClinicalTrials.gov: NCT03056755 (registration date: February 17, 2017).

A Phase I Study of the Oral Dual-Acting Pan-PI3K/mTOR Inhibitor Bimiralisib in Patients with Advanced Solid Tumors.

BACKGROUND: Bimiralisib is a pan-PI3K/mTOR inhibitor demonstrating antitumor efficacy in preclinical models. The objectives of this study were to identify a maximum tolerated dose (MTD), pharmacokinetics (PK), a dosing schedule, and adverse events (AEs) in patients with advanced solid tumors. PATIENTS AND METHODS: Patients received oral bimiralisib to determine the MTD of one continuous (once daily) and two intermittent schedules (A: Days 1, 2 weekly; B: Days 1, 4 weekly) until progression or unacceptable AEs occurred. RESULTS: The MTD for the continuous schedule was 80 mg, with grade three fatigue as the dose-limiting toxicity (DLT). No MTD was reached with intermittent schedules, with only one DLT in schedule B. PK analysis suggested that 140 mg (schedule A) was within the biologically active dose range and was selected for further exploration. The most frequent treatment-emergent AEs were hyperglycemia (76.2%) in the continuous schedule, and nausea (56-62.5%) in schedules A and B. The most frequent treatment-emergent > grade three AE for all schedules combined was hyperglycemia (28.6%, continuous schedule; 12.0%, schedule A; 12.5%, schedule B). There was one partial response in a head and neck squamous cancer patient with a NOTCH1T1997M mutation. CONCLUSIONS: Bimiralisib demonstrated a manageable AE profile consistent with this compound class. Intermittent schedules had fewer > grade three AEs, while also maintaining favorable PK profiles. Intermittent schedule A is proposed for further development in biomarker-selected patient populations.

Immunization with V987H-stabilized Spike glycoprotein protects K18-hACE2 mice and golden Syrian hamsters upon SARS-CoV-2 infection.

Safe and effective severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines are crucial to fight against the coronavirus disease 2019 pandemic. Most vaccines are based on a mutated version of the Spike glycoprotein [K986P/V987P (S-2P)] with improved stability, yield and immunogenicity. However, S-2P is still produced at low levels. Here, we describe the V987H mutation that increases by two-fold the production of the recombinant Spike and the exposure of the receptor binding domain (RBD). S-V987H immunogenicity is similar to S-2P in mice and golden Syrian hamsters (GSH), and superior to a monomeric RBD. S-V987H immunization confer full protection against severe disease in K18-hACE2 mice and GSH upon SARS-CoV-2 challenge (D614G or B.1.351 variants). Furthermore, S-V987H immunized K18-hACE2 mice show a faster tissue viral clearance than RBD- or S-2P-vaccinated animals challenged with D614G, B.1.351 or Omicron BQ1.1 variants. Thus, S-V987H protein might be considered for future SARS-CoV-2 vaccines development.

Co-clinical Trial of Novel Bispecific Anti-HER2 Antibody Zanidatamab in Patient-Derived Xenografts.

Zanidatamab is a bispecific human epidermal growth factor receptor 2 (HER2)-targeted antibody that has demonstrated antitumor activity in a broad range of HER2-amplified/expressing solid tumors. We determined the antitumor activity of zanidatamab in patient-derived xenograft (PDX) models developed from pretreatment or postprogression biopsies on the first-in-human zanidatamab phase I study (NCT02892123). Of 36 tumors implanted, 19 PDX models were established (52.7% take rate) from 17 patients. Established PDXs represented a broad range of HER2-expressing cancers, and in vivo testing demonstrated an association between antitumor activity in PDXs and matched patients in 7 of 8 co-clinical models tested. We also identified amplification of MET as a potential mechanism of acquired resistance to zanidatamab and demonstrated that MET inhibitors have single-agent activity and can enhance zanidatamab activity in vitro and in vivo. These findings provide evidence that PDXs can be developed from pretreatment biopsies in clinical trials and may provide insight into mechanisms of resistance. SIGNIFICANCE: We demonstrate that PDXs can be developed from pretreatment and postprogression biopsies in clinical trials and may represent a powerful preclinical tool. We identified amplification of MET as a potential mechanism of acquired resistance to the HER2 inhibitor zanidatamab and MET inhibitors alone and in combination as a therapeutic strategy. This article is featured in Selected Articles from This Issue, p. 695.

Biphasic MERS-CoV Incidence in Nomadic Dromedaries with Putative Transmission to Humans, Kenya, 2022-2023.

Middle East respiratory syndrome coronavirus (MERS-CoV) is endemic in dromedaries in Africa, but camel-to-human transmission is limited. Sustained 12-month sampling of dromedaries in a Kenya abattoir hub showed biphasic MERS-CoV incidence; peak detections occurred in October 2022 and February 2023. Dromedary-exposed abattoir workers (7/48) had serologic signs of previous MERS-CoV exposure.

Sunitinib in Patients With Breast Cancer With FGFR1 or FGFR2 Amplifications or Mutations: Results From the Targeted Agent and Profiling Utilization Registry Study.

PURPOSE: The Targeted Agent and Profiling Utilization Registry Study is a phase II basket trial evaluating the antitumor activity of commercially available targeted agents in patients with advanced cancer and genomic alterations known to be drug targets. Results from cohorts of patients with metastatic breast cancer (BC) with FGFR1 and FGFR2 alterations treated with sunitinib are reported. METHODS: Eligible patients had measurable disease, Eastern Cooperative Oncology Group performance status 0-2, adequate organ function, and no standard treatment options. Simon's two-stage design was used with a primary end point of disease control (DC), defined as objective response (OR) or stable disease of at least 16 weeks duration (SD16+) according to RECIST v1.1. Secondary end points included OR, progression-free survival, overall survival, duration of response, duration of stable disease, and safety. RESULTS: Forty patients with BC with FGFR1 (N = 30; amplification only n = 26, mutation only n = 1, both n = 3) or FGFR2 (N = 10; amplification only n = 2, mutation only n = 6, both n = 2) alterations were enrolled. Three patients in the FGFR1 cohort were not evaluable for efficacy; all patients in the FGFR2 cohort were evaluable. For the FGFR1 cohort, two patients with partial response and four with SD16+ were observed for DC and OR rates of 27% (90% CI, 13 to 100) and 7% (95% CI, 1 to 24), respectively. The null hypothesis of 15% DC rate was not rejected (P = .169). No patients achieved DC in the FGFR2 cohort (P = 1.00). Thirteen of the 40 total patients across both cohorts had at least one grade 3-4 adverse event or serious adverse event at least possibly related to sunitinib. CONCLUSION: Sunitinib did not meet prespecified criteria to declare a signal of antitumor activity in patients with BC with either FGFR1 or FGFR2 alterations. Other treatments and clinical trials should be considered for these patient populations.

First-In-Human Phase I Study of Tinengotinib (TT-00420), a Multiple Kinase Inhibitor, as a Single Agent in Patients With Advanced Solid Tumors.

PURPOSE: This first-in-human phase I dose-escalation study evaluated the safety, pharmacokinetics, and efficacy of tinengotinib (TT-00420), a multi-kinase inhibitor targeting fibroblast growth factor receptors 1-3 (FGFRs 1-3), Janus kinase 1/2, vascular endothelial growth factor receptors, and Aurora A/B, in patients with advanced solid tumors. PATIENTS AND METHODS: Patients received tinengotinib orally daily in 28-day cycles. Dose escalation was guided by Bayesian modeling using escalation with overdose control. The primary objective was to assess dose-limiting toxicities (DLTs), maximum tolerated dose (MTD), and dose recommended for dose expansion (DRDE). Secondary objectives included pharmacokinetics and efficacy. RESULTS: Forty-eight patients were enrolled (dose escalation, n = 40; dose expansion, n = 8). MTD was not reached; DRDE was 12 mg daily. DLTs were palmar-plantar erythrodysesthesia syndrome (8 mg, n = 1) and hypertension (15 mg, n = 2). The most common treatment-related adverse event was hypertension (50.0%). In 43 response-evaluable patients, 13 (30.2%) achieved partial response (PR; n = 7) or stable disease (SD) ≥ 24 weeks (n = 6), including 4/11 (36.4%) with FGFR2 mutations/fusions and cholangiocarcinoma (PR n = 3; SD ≥ 24 weeks n = 1), 3/3 (100.0%) with hormone receptor (HR)-positive/HER2-negative breast cancer (PR n = 2; SD ≥ 24 weeks n = 1), 2/5 (40.0%) with triple-negative breast cancer (TNBC; PR n = 1; SD ≥ 24 weeks n = 1), and 1/1 (100.0%) with castrate-resistant prostate cancer (CRPC; PR). Four of 12 patients (33.3%; HR-positive/HER2-negative breast cancer, TNBC, prostate cancer, and cholangiocarcinoma) treated at DRDE had PRs. Tinengotinib's half-life was 28-34 hours. CONCLUSIONS: Tinengotinib was well tolerated with favorable pharmacokinetic characteristics. Preliminary findings indicated potential clinical benefit in FGFR inhibitor-refractory cholangiocarcinoma, HER2-negative breast cancer (including TNBC), and CRPC. Continued evaluation of tinengotinib is warranted in phase II trials.

Plitidepsin as an Immunomodulator against Respiratory Viral Infections.

Plitidepsin is a host-targeted compound known for inducing a strong anti-SARS-CoV-2 activity, as well as for having the capacity of reducing lung inflammation. Because IL-6 is one of the main cytokines involved in acute respiratory distress syndrome, the effect of plitidepsin in IL-6 secretion in different in vitro and in vivo experimental models was studied. A strong plitidepsin-mediated reduction of IL-6 was found in human monocyte-derived macrophages exposed to nonproductive SARS-CoV-2. In resiquimod (a ligand of TLR7/8)-stimulated THP1 human monocytes, plitidepsin-mediated reductions of IL-6 mRNA and IL-6 levels were also noticed. Additionally, although resiquimod-induced binding to DNA of NF-κB family members was unaffected by plitidepsin, a decrease in the regulated transcription by NF-κB (a key transcription factor involved in the inflammatory cascade) was observed. Furthermore, the phosphorylation of p65 that is required for full transcriptional NF-κB activity was significantly reduced by plitidepsin. Moreover, decreases of IL-6 levels and other proinflammatory cytokines were also seen in either SARS-CoV-2 or H1N1 influenza virus-infected mice, which were treated at low enough plitidepsin doses to not induce antiviral effects. In summary, plitidepsin is a promising therapeutic agent for the treatment of viral infections, not only because of its host-targeted antiviral effect, but also for its immunomodulatory effect, both of which were evidenced in vitro and in vivo by the decrease of proinflammatory cytokines.

Convergent MAPK pathway alterations mediate acquired resistance to FGFR inhibitors in FGFR2 fusion-positive cholangiocarcinoma.

BACKGROUND & AIMS: There is a knowledge gap in understanding mechanisms of resistance to fibroblast growth factor receptor (FGFR) inhibitors (FGFRi) and a need for novel therapeutic strategies to overcome it. We investigated mechanisms of acquired resistance to FGFRi in patients with FGFR2-fusion-positive cholangiocarcinoma (CCA). METHODS: A retrospective analysis of patients who received FGFRi therapy and underwent tumor and/or cell-free DNA analysis, before and after treatment, was performed. Longitudinal circulating tumor DNA samples from a cohort of patients in the phase I trial of futibatinib (NCT02052778) were assessed. FGFR2-BICC1 fusion cell lines were developed and secondary acquired resistance mutations in the mitogen-activated protein kinase (MAPK) pathway were introduced to assess their effect on sensitivity to FGFRi in vitro. RESULTS: On retrospective analysis of 17 patients with repeat sequencing following FGFRi treatment, new FGFR2 mutations were detected in 11 (64.7%) and new alterations in MAPK pathway genes in nine (52.9%) patients, with seven (41.2%) patients developing new alterations in both the FGFR2 and MAPK pathways. In serially collected plasma samples, a patient treated with an irreversible FGFRi tested positive for previously undetected BRAF V600E, NRAS Q61K, NRAS G12C, NRAS G13D and KRAS G12K mutations upon progression. Introduction of a FGFR2-BICC1 fusion into biliary tract cells in vitro sensitized the cells to FGFRi, while concomitant KRAS G12D or BRAF V600E conferred resistance. MEK inhibition was synergistic with FGFRi in vitro. In an in vivo animal model, the combination had antitumor activity in FGFR2 fusions but was not able to overcome KRAS-mediated FGFRi resistance. CONCLUSIONS: These findings suggest convergent genomic evolution in the MAPK pathway may be a potential mechanism of acquired resistance to FGFRi. CLINICAL TRIAL NUMBER: NCT02052778. IMPACT AND IMPLICATIONS: We evaluated tumors and plasma from patients who previously received inhibitors of fibroblast growth factor receptor (FGFR), an important receptor that plays a role in cancer cell growth, especially in tumors with abnormalities in this gene, such as FGFR fusions, where the FGFR gene is fused to another gene, leading to activation of cancer cell growth. We found that patients treated with FGFR inhibitors may develop mutations in other genes such as KRAS, and this can confer resistance to FGFR inhibitors. These findings have several implications for patients with FGFR2 fusion-positive tumors and provide mechanistic insight into emerging MAPK pathway alterations which may serve as a therapeutic vulnerability in the setting of acquired resistance to FGFRi.

Middle East respiratory coronavirus (MERS-CoV) internalized by llama alveolar macrophages does not result in virus replication or induction of pro-inflammatory cytokines.

Severe Middle East respiratory syndrome (MERS) is characterized by massive infiltration of immune cells in lungs. MERS-coronavirus (MERS-CoV) replicates in vitro in human macrophages, inducing high pro-inflammatory responses. In contrast, camelids, the main reservoir for MERS-CoV, are asymptomatic carriers. Although limited infiltration of leukocytes has been observed in the lower respiratory tract of camelids, their role during infection remains unknown. Here we studied whether llama alveolar macrophages (LAMs) are susceptible to MERS-CoV infection and can elicit pro-inflammatory responses. MERS-CoV did not replicate in LAMs; however, they effectively capture and degrade viral particles. Moreover, transcriptomic analyses showed that LAMs do not induce pro-inflammatory cytokines upon MERS-CoV sensing.

Phase I Study of mTORC1/2 Inhibitor Sapanisertib (CB-228/TAK-228) in Combination with Metformin in Patients with mTOR/AKT/PI3K Pathway Alterations and Advanced Solid Malignancies.

BACKGROUND: Sapanisertib (CB-228/TAK-228) is a potent, selective ATP-competitive, dual inhibitor of mTORC1/2. Metformin is thought to inhibit the mTOR pathway through upstream activation of 5'-AMP-activated protein kinase (AMPK) suggesting combination therapy may enhance antitumor activity of sapanisertib. We report preliminary safety, tolerability, and efficacy from the dose-escalation study of sapanisertib in combination with metformin in patients with advanced solid tumors. METHODS: Patients with advanced metastatic solid tumors resistant or refractory to standard treatment, with and without mTOR/AKT/PI3K pathway alterations, received sapanisertib 3 or 4 mg daily together with metformin once to three times daily (500-1,500 mg). All patients underwent 14-day titration period for metformin in cycle 1. Tumor measurements were performed following cycle 2 and subsequently every 8 weeks. RESULTS: A total of 30 patients were enrolled across four cohorts (3 mg/500 mg; 3 mg/1,000 mg, 4 mg/1,000 mg; 4 mg/1,500 mg). 19 were female (63%), median age was 57 (range: 30-77), all were Eastern Cooperative Oncology Group performance status 1. Tumor types included sarcoma (6), breast (4), ovarian (4), head and neck (3), colorectal (2), lung (2), renal cell (2), endometrial (2), gastroesophageal junction (1), prostate (1), stomach (1), urachus (1), and cervical cancer (1). Median number of prior lines of therapy was 4. Most common genomic alterations included PIK3CA (27%), PTEN (17%), AKT1/2 (10%), mTOR (10%). Of 30 patients evaluable for response, 4 patients achieved partial response (PR); 15 patients achieved stable disease (SD) as best response. Disease control rate (PR+SD) was 63%. Of the responders in PR, 3 of 4 patients had documented PTEN mutations (3/5 patients enrolled with PTEN mutations had PR); 2 of 4 of patients in PR had comutations (patient with leiomyosarcoma had both PTEN and TSC; patient with breast cancer had both PTEN and STK11); 1 of 4 patients in PR had AKT and mTOR mutation; tumor types included leiomyosarcoma (n = 2), breast (n = 1), and endometrial cancer (n = 1). Most common treatment-emergent adverse events included nausea, anorexia, diarrhea, and rash. Grade (G) 3-5 treatment-related adverse events included hyperglycemia (4/30; 13%), fatigue (2/30; 7%), hypertriglyceridemia (1/30; 3%), rash (2/20; 7%), diarrhea (2/30; 7%), creatinine increase (1/30; 3%), acidosis (1/30; 3%). No dose-limiting toxicities (DLT) were reported in the 3 mg/500 mg cohort. One of 6 patient had DLT in the 3 mg/1,000 mg cohort (G3 diarrhea) and 2 of 11 patients had DLTs in the 4 mg/1,500 mg cohort (G3 fatigue, G3 rash). 4 mg/1,000 mg was defined as the MTD. CONCLUSIONS: The safety profile of mTORC1/2 inhibitor sapanisertib in combination with metformin was generally tolerable, with antitumor activity observed in patients with advanced malignancies harboring PTEN mutations and AKT/mTOR pathway alterations. SIGNIFICANCE: Sapanisertib (CB-228/TAK-228) is a potent, selective ATP-competitive, next-generation dual inhibitor of mTORC1/2. Metformin is thought to inhibit the mTOR pathway through upstream activation of AMPK suggesting combination therapy may enhance antitumor activity of sapanisertib. This dose-escalation study of sapanisertib and metformin in advanced solid tumors and mTOR/AKT/PI3K pathway alterations, demonstrates safety, tolerability, and early clinical activity in advanced malignancies harboring PTEN mutations and AKT/mTOR pathway alterations.Clinical trial information: NCT03017833.

Novel Spike-stabilized trimers with improved production protect K18-hACE2 mice and golden Syrian hamsters from the highly pathogenic SARS-CoV-2 Beta variant.

Most COVID-19 vaccines are based on the SARS-CoV-2 Spike glycoprotein (S) or their subunits. However, S shows some structural instability that limits its immunogenicity and production, hampering the development of recombinant S-based vaccines. The introduction of the K986P and V987P (S-2P) mutations increases the production and immunogenicity of the recombinant S trimer, suggesting that these two parameters are related. Nevertheless, S-2P still shows some molecular instability and it is produced with low yield. Here we described a novel set of mutations identified by molecular modeling and located in the S2 region of the S-2P that increase its production up to five-fold. Besides their immunogenicity, the efficacy of two representative S-2P-based mutants, S-29 and S-21, protecting from a heterologous SARS-CoV-2 Beta variant challenge was assayed in K18-hACE2 mice (an animal model of severe SARS-CoV-2 disease) and golden Syrian hamsters (GSH) (a moderate disease model). S-21 induced higher level of WH1 and Delta variants neutralizing antibodies than S-2P in K18-hACE2 mice three days after challenge. Viral load in nasal turbinate and oropharyngeal samples were reduced in S-21 and S-29 vaccinated mice. Despite that, only the S-29 protein protected 100% of K18-hACE2 mice from severe disease. When GSH were analyzed, all immunized animals were protected from disease development irrespectively of the immunogen they received. Therefore, the higher yield of S-29, as well as its improved immunogenicity and efficacy protecting from the highly pathogenic SARS-CoV-2 Beta variant, pinpoint the S-29 mutant as an alternative to the S-2P protein for future SARS-CoV-2 vaccine development.