ARF6 is a host factor for SARS-CoV-2 infection in vitro

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a newly emerged beta-coronavirus that enter cells via two routes, direct fusion at the plasma membrane or endocytosis followed by fusion with the late endosome/lysosome. While the viral receptor, ACE2, multiple entry factors and the mechanism of fusion of the virus at the plasma membrane have been investigated extensively, viral entry via the endocytic pathway is less understood. By using a human hepatocarcinoma cell line, Huh-7, which is resistant to the antiviral action of the TMPRSS2 inhibitor camostat, we discovered that SARS-CoV-2 entry is not dependent on dynamin but on cholesterol. ADP-ribosylation factor 6 (ARF6) has been described as a host factor for SARS-CoV-2 replication and is involved in the entry and infection of several pathogenic viruses. Using CRISPR/Cas9 genetic deletion, a modest reduction in SARS-CoV-2 uptake and infection in Huh-7 was observed. In addition, pharmacological inhibition of ARF6 with the small molecule NAV-2729 showed a dose-dependent reduction of viral infection. Importantly, NAV-2729 also reduced SARS-CoV-2 viral loads in more physiological models of infection: Calu-3 cells and kidney organoids. This highlighted a role for ARF6 in multiple cell contexts. Together, these experiments point to ARF6 as a putative target to develop antiviral strategies against SARS-CoV-2.

ARF6 is a host factor for SARS-CoV-2 infection in vitro

SARS-CoV-2 is a newly emerged beta-coronavirus that enter cells via two routes, direct fusion at the plasma membrane or endocytosis followed by fusion with the late endosome/lysosome. While the viral receptor, ACE2, multiple entry factors, and the mechanism of fusion of the virus at the plasma membrane have been extensively investigated, viral entry via the endocytic pathway is less understood. By using a human hepatocarcinoma cell line, Huh-7, which is resistant to the antiviral action of the TMPRSS2 inhibitor camostat, we discovered that SARS-CoV-2 entry is not dependent on dynamin but dependent on cholesterol. ADP-ribosylation factor 6 (ARF6) has been described as a host factor for SARS-CoV-2 replication and it is involved in the entry and infection of several pathogenic viruses. Using CRISPR-Cas9 genetic deletion, we observed that ARF6 is important for SARS-CoV-2 uptake and infection in Huh-7. This finding was corroborated using a pharmacologic inhibitor, whereby the ARF6 inhibitor NAV-2729 showed a dose-dependent inhibition of viral infection. Importantly, NAV-2729 reduced SARS-CoV-2 viral loads also in more physiologic models of infection: Calu-3 and kidney organoids. This highlighted the importance of ARF6 in multiple cell contexts. Together, these experiments points to ARF6 as a putative target to develop antiviral strategies against SARS-CoV-2.

A phase II study of temsirolimus added to low-dose weekly carboplatin and paclitaxel for patients with recurrent and/or metastatic (R/M) head and neck squamous cell carcinoma (HNSCC)

Background

Activating events along the PI3K/mTOR pathway are common in head and neck squamous cell carcinomas (HNSCC), and preclinical studies suggest additive or synergistic effects when combining mTORC1 inhibitors with carboplatin and paclitaxel chemotherapy.

Patients and methods

In this single-institution phase II study, the combination of temsirolimus 25 mg, carboplatin AUC 1.5, and paclitaxel 80 mg/m2 administered on days 1 and 8 of a 21-day cycle was evaluated in 36 patients with recurrent and/or metastatic (R/M) HNSCC. The primary end point was objective response rate after two cycles of treatment. Secondary end points include the safety and tolerability profile and overall survival. Correlative studies with exome mutational analysis were performed in pre-treatment biopsy samples from 21 patients.

Results

Fifteen (41.7%) patients had an objective response, which were all partial responses, and 19 (52.3%) patients had stable disease as best response. The two patients who were designated as 'non-responders' were removed from study prior to two cycles of treatment, but are included in the efficacy and safety analyses. The median duration on study was 5.3 months and the median progression-free survival and overall survival were 5.9 months (95% confidence interval, 4.8-7.1) and 12.8 months (95% confidence interval, 9.8-15.8), respectively. The most common grade 3 and 4 adverse events were hematologic toxicities. Three (3.8%) patients developed neutropenic fever on study. Three of four patients with PIK3CA mutations experienced tumor regressions, and responses were also seen in patients with other genetic alterations in the PI3K/mTOR pathway.

Conclusion

The combination of temsirolimus with low-dose weekly carboplatin and paclitaxel appears to have meaningful clinical efficacy in the treatment of R/M HNSCC. This regimen has a relatively high response rate compared to other treatments evaluated in R/M HNSCC, and potential associations with genetic alterations in the PI3K/mTOR pathway should be further explored.

A phase II study of axitinib (AG-013736) in patients with incurable adenoid cystic carcinoma

BACKGROUND

Recurrent/metastatic adenoid cystic carcinoma (ACC) is an incurable disease with no standard treatments. The majority of ACCs express the oncogenic transcription factor MYB (also c-myb), often in the context of a MYB gene rearrangement. This phase II trial of the tyrosine kinase inhibitor (TKI) axitinib (Pfizer) tested the hypothesis that targeting pathways activated by MYB can be therapeutically effective for ACC.

PATIENTS AND METHODS

This is a minimax two-stage, phase II trial that enrolled patients with incurable ACC of any primary site. Progressive or symptomatic disease was required. Patients were treated with axitinib 5 mg oral twice daily; dose escalation was allowed. The primary end point was best overall response (BOR). An exploratory analysis correlating biomarkers to drug benefit was conducted, including next-generation sequencing (NGS) in 11 patients.

RESULTS

Thirty-three patients were registered and evaluable for response. Fifteen patients had the axitinib dose increased. Tumor shrinkage was achieved in 22 (66.7%); 3 (9.1%) had confirmed partial responses. Twenty-five (75.8%) patients had stable disease, 10 of whom had disease stability for >6 months. The median progression-free survival (PFS) was 5.7 months (range 0.92-21.8 months). Grade 3 axitinib-related toxicities included hypertension, oral pain and fatigue. A trend toward superior PFS was noted with the MYB/NFIB rearrangement, although this was not statistically significant. NGS revealed three tumors with 4q12 amplification, producing increased copies of axitinib-targeted genes PDGFR/KDR/KIT. Two 4q12 amplified patients achieved stable disease for >6 months, including one with significant tumor reduction and the longest PFS on study (21.8 months).

CONCLUSIONS

Although the primary end point was not met, axitinib exhibited clinical activity with tumor shrinkage achieved in the majority of patients with progressive disease before trial enrollment. Analysis of MYB biomarkers and genomic profiling suggests the hypothesis that 4q12 amplified ACCs are a disease subset that benefit from TKI therapy.

Phase I study of weekly nab-paclitaxel + weekly cetuximab + intensity-modulated radiation therapy (IMRT) in patients with stage III-IVB head and neck squamous cell carcinoma (HNSCC)

BACKGROUND

There is a clinical need to improve the efficacy of standard cetuximab + concurrent intensity-modulated radiation therapy (IMRT) for patients with locally and/or regionally advanced HNSCC. Taxanes have radiosensitizing activity against HNSCC, and nab-paclitaxel may offer therapeutic advantage in comparison with other taxanes.

PATIENTS AND METHODS

This was a single-institution phase I study with a modified 3 + 3 design. Four dose levels (DLs) of weekly nab-paclitaxel were explored (30, 45, 60, and 80 mg/m(2)), given with standard weekly cetuximab (450 mg/m(2) loading dose followed by 250 mg/m(2) weekly) and concurrent IMRT (total dose, 70 Gy).

RESULTS

Twenty-five eligible patients (20 M, 5 F) enrolled, with median age 58 years (range, 46-84 years). Primary tumor sites were oropharynx, 19 (10 human papillomavirus [HPV] pos, 8 HPV neg, 1 not done); neck node with unknown primary, 2; larynx 2; and oral cavity and maxillary sinus, 1 each. Seven patients had received prior induction chemotherapy. Maximum tolerated dose (MTD) was exceeded at DL4 (nab-paclitaxel, 80 mg/m(2)) with three dose-limiting toxicities (DLTs) (grade 3 neuropathy, grade 3 dehydration, with grade 3 mucositis grade 3 anemia) among five assessable patients. There was only one DLT (grade 3 supraventricular tachycardia) among six patients at DL3 (nab-paclitaxel, 60 mg/m(2)), and this was deemed the MTD. Among 23 assessable patients, the most common ≥ g3 AEs were lymphopenia 100%, functional mucositis 65%, and pain in throat/oral cavity 52%. At a median follow-up of 33 months, 2-year failure-free survival (FFS) is 65% [95% confidence interval (CI) 42% to 81%] and 2-year overall survival (OS) is 91% (95% CI 69-97).

CONCLUSION

The recommended phase II dose for nab-paclitaxel is 60 mg/m(2) weekly when given standard weekly cetuximab and concurrent IMRT. This regimen merits further study as a nonplatinum alternative to IMRT + cetuximab alone.

CLINICALTRIALSGOV ID

NCT00736619.

Phase II study of depsipeptide (DEP) in radioiodine (RAI)-refractory metastatic nonmedullary thyroid carcinoma

6059

Background: Historically, systemic therapy for radioactive iodine (RAI)-refractory thyroid cancer has been understudied. Available drugs have modest efficacy. Depsipeptide (DEP) is a histone deacetylase inhibitor with potent anti-tumor effects both in vitro and in vivo. In thyroid cancer cell lines, DEP increases expression of both thyroglobulin and the sodium/iodine symporter messenger RNAs, offering the possibility of improved iodine concentrating ability of radioactive iodine (RAI)-resistant tumors. Methods: Eligible patients (pts) must have progressive, RAI-refractory, recurrent/metastatic, non-medullary, non-anaplastic thyroid cancer; RECIST measurable disease; and adequate organ/marrow function. Exclusionary criteria include prior chemotherapy in the recurrent/metastatic setting; cardiac disease or dysfunction; QTc prolongation or co-administration of drugs that prolong the QTc. DEP 13 mg/m2 IV is administered on days 1, 8, 15, every 28 days. The primary endpoint is response rate by RECIST criteria; change in RAI avidity is a secondary endpoint. The study closed early due to poor accrual after an unexpected grade 5 adverse event (AE) that prompted protocol suspension. Results: 20 pts were enrolled: female-50%; median age-64 years; histology-papillary (8)/follicular (1)/Hürthle (11). Grade 4–5 AE possibly related to drug: grade 5 sudden death (1); grade 4 -pulmonary embolus (1). Twelve of 20 subjects had a reported AE. No RECIST major responses have been seen. Evaluation of response: stable disease (10); progression (3); early death (1); unknown/inevaluable (6: 5 - temporary protocol suspension; 1 - withdrew consent). Restoration of RAI avidity was documented in 2 pts. For evaluable patients (14) only, median overall survival and time on study was 36 (.5–45+) months and 1.7 (0.46–12) months, respectively. Conclusions: We observed preliminary signs of in vivo reversal of RAI resistance after treatment with DEP. However, no major responses were observed and accrual was poor after the grade 5 AE. (Study funded by grant N01 CM 62206)

No significant financial relationships to disclose.

The Collection of Indirect and Nonmedical Direct Costs (COIN) form: a new tool for collecting the invisible costs of androgen independent prostate carcinoma

BACKGROUND

There are limited data available regarding the cost of care in patients with androgen independent prostate carcinoma (AIPC), and there are no data on the impact of direct nonmedical and indirect costs (DNM/IC). This lack of data, along with the feasibility of collecting DNM/IC, was examined in patients with AIPC who took part in a randomized trial using a newly developed questionnaire, the Collection of Indirect and Nonmedical Direct Costs (COIN) form.

METHODS

Patients with AIPC were randomized to one of three treatment arms: 1) strontium only (strontium 4 Mci in Week 1 and Week 12) (STRONT); 2) vinblastine 4 mg/m(2) per week for 3 weeks then 1 week off and estramustine, 10 mg/kg per day (CHEMO); or 3) a combination of treatments outlined in the arms for CHEMO and STRONT (CHEMO/STRONT). Direct medical costs were collected through the hospital billing system. DNM/IC data were obtained prospectively using the COIN form. Cost data were analyzed for a period of 6 months.

RESULTS

Twenty-nine patients were randomized, after which the protocol was closed because of poor accrual. The median survival of the patients was 22.3 months. The mean and median total costs for the 20 of 29 patients with complete cost information were $12,647 and $11,257 over 6 months, respectively. DNM/IC represented 11% of the total cost (range, from < 1% to 42%); in 20% of participating individuals, these costs accounted for 35-42% of total costs. Failure to collect complete cost information was due to early death, administrative difficulties, and loss to follow-up.

CONCLUSIONS

In this pilot project, the collection of these cost data using the COIN form was feasible and practical and was limited primarily by logistic, not form specific, issues. DNM/IC were found to be a significant proportion of total costs (up to 42%) in selected patients, and this information proved to be a useful addition to the cost analysis. Approximately 98 patients would be required to detect a 20% difference in total costs between arms in a properly powered, randomized trial. Considering the potentially significant impact on total costs, DNM/IC data should be included in future cost-analysis studies of patients with AIPC and other diseases.

Clinical economics of head and neck malignancies

With the continued increase in medical expenditures and the growing awareness that resources are not limitless, there is increasing pressure to curb health care costs and to establish priorities. As potential solutions are proposed and implemented, there is understandable concern that policy choices may adversely affect both the access to and the quality of care. Economic analyses are one tool used to optimize resource allocation decisions. The primary goal of these analyses is to maximize value and efficiency, not necessarily to decrease spending. The current focus on cost cutting is often associated with a more truncated, nonsocietal perspective (e.g., that of the payer or provider). To be most useful, these analyses must be methodologically rigorous. Standard guidelines, such as those established by Eisenberg, are helpful. As shown in the reports applicable to head and neck malignancies that have been discussed here, many articles published in the clinical literature must be interpreted cautiously, because fundamental methodological concerns (e.g., using costs rather than charges, discounting to a common base year) were frequently not addressed. Economic investigations are one aspect of the broader fields of outcomes and health services research. It is easy to underestimate how greatly economic studies depend on the availability of high quality noneconomic data. In that context, current initiatives in evidence-based medicine (EBM), using the best available evidence (considering for example, the type of trial, the quality of the research, and the credentials of the researcher) to help clinicians practice in situations where doubt may exist in the diagnosis, treatment, or prognosis of patients, will likely grow in importance. Evidence-based clinical practice guidelines and systematic literature reviews are manifestations of this trend. Historically, disease control measures and survival have been the primary and points in clinical cancer studies. Economic analyses and studies evaluating other end points (e.g., function, quality of life) will likely play a larger role in the future in evaluating the diagnosis, treatment, and follow-up of head, neck and other malignancies.