Clinical study on collagen gel droplet-embedded culture drug sensitivity test for multidrug combination chemotherapy and super selective intra-arterial infusion chemoradiotherapy in oral squamous cell carcinoma

Benefits of functional assays in personalized cancer medicine: more than just a proof-of-concept

As complex and heterogeneous diseases, cancers require a more tailored therapeutic management than most pathologies. Recent advances in anticancer drug development, including the immuno-oncology revolution, have been too often plagued by unsatisfying patient response rates and survivals. In reaction to this, cancer care has fully transitioned to the “personalized medicine” concept. Numerous tools are now available tools to better adapt treatments to the profile of each patient. They encompass a large array of diagnostic assays, based on biomarkers relevant to targetable molecular pathways. As a subfamily of such so-called companion diagnostics, chemosensitivity and resistance assays represent an attractive, yet insufficiently understood, approach to individualize treatments. They rely on the assessment of a composite biomarker, the ex vivo functional response of cancer cells to drugs, to predict a patient's outcome. Systemic treatments, such as chemotherapies, as well as targeted treatments, whose efficacy cannot be fully predicted yet by other diagnostic tests, may be assessed through these means. The results can provide helpful information to assist clinicians in their decision-making process. We explore here the most advanced functional assays across oncology indications, with an emphasis on tests already displaying a convincing clinical demonstration. We then recapitulate the main technical obstacles faced by researchers and clinicians to produce more accurate, and thus more predictive, models and the recent advances that have been developed to circumvent them. Finally, we summarize the regulatory and quality frameworks surrounding functional assays to ensure their safe and performant clinical implementation. Functional assays are valuable in vitro diagnostic tools that already stand beyond the “proof-of-concept” stage. Clinical studies show they have a major role to play by themselves but also in conjunction with molecular diagnostics. They now need a final lift to fully integrate the common armament used against cancers, and thus make their way into the clinical routine.

Optimal Contact Concentration of Paclitaxel in the Collagen Gel Droplet-Embedded Culture Drug Sensitivity Test for Human Oral Squamous Cell Carcinoma and Evaluation of Combination with Cetuximab

OBJECTIVE

A combination of the taxane anticancer drug paclitaxel (PTX) and molecular target drug cetuximab (cMab) is effective for the treatment of head and neck squamous cell carcinoma (HNSCC). However, its use is associated with serious side effects, such as neuropathy and myelosuppression. In addition, it is administered regardless of patient sensitivity because biomarkers indicating its efficacy are unavailable. Therefore, we investigated the usefulness of setting the indicated contact concentration of PTX and predicted the antitumor effect of combined contact with cMab using the collagen gel droplet-embedded culture drug sensitivity test (CD-DST).

METHOD

Twelve human oral squamous cell carcinoma (OSCC) cell lines (i.e., SAS, HSC-2, HSC-3, HSC-4, OSC-19, OSC-20, KON, HO-1-N-1, HO-1-u-1, SAT, SCC-4, and Nialym) were used. Using the CD-DST, we calculated the optimal contact concentration of the cells with PTX based on the clinical response rate of HNSCC and evaluated the combined contact with cMab. Furthermore, nude mice were treated with standalone PTX and PTX + cMab, and the results were compared with those of the CD-DST.

RESULTS

Based on the CD-DST, 0.1 μg/mL was the optimal contact concentration of PTX, to which the cells showed dose-dependent sensitivity. Moreover, the CD-DST method was used to evaluate the antitumor effects on OSCC even when PTX was used in combination with cMab. The antitumor effects in the CD-DST and nude mice were correlated (p < 0.05).

CONCLUSION

The CD-DST results suggested that it was possible to predict the clinical effects of single-contact PTX and the enhancing effect of cMab + PTX.

Identification of the optimal cetuximab concentration that is effective against oral squamous cell carcinoma in collagen gel droplet embedded culture drug sensitivity testing

Anticancer drug sensitivity testing using the collagen gel droplet embedded culture drug sensitivity test (CD-DST) on oral squamous cell carcinoma (OSCC) samples beginning from 2010 has been conducted. The present study investigated the effect of adding cetuximab (Erbitux^®), a molecularly targeted drug, on anticancer drug activity against clinical OSCC specimens. A total of 25 specimens were obtained from 25 patients with OSCC between October 2013 and December 2017. The present study conducted anticancer drug sensitivity testing for cisplatin (CDDP), 5-fluorouracil (5-FU), cetuximab, three-drug combination, single agent and multi drug combinations, and cetuximab addition to the aforementioned regimens using CD-DST. In addition, the optimum concentration of each drug was evaluated. The overall evaluation success rate of the CD-DST method for OSCC specimens was 84.0% (21 of 25 cases); sensitivity to anticancer drugs and cetuximab could be evaluated. The in vitro efficacy rate of a cetuximab single agent and CDDP + 5-FU (PF) at a cut-off value of 50% was similar to the known clinical response rate. However, at a cut-off value of 50%, the in vitro efficacy of PF + cetuximab was calculated to be 40%, which was higher than the clinical response rate. The CD-DST method could be used to evaluate cetuximab, a molecularly targeted drug. Furthermore, its additive effect on conventional chemotherapy could be evaluated. The CD-DST method is suitable for evaluating and selecting chemotherapy regimens, including molecularly targeted drugs. Future studies are required to generate and evaluate relevant clinical data.