Another treatment option coming down the pike: TAS-102


Fight Colorectal Cancer stays actively involved in the research process from beginning to end. Part of our role in research is monitoring the progress of new drugs – drugs that may be used in treatment plans of colorectal cancer in the future. We actively work with drug companies to stay up-to-date on the latest treatments so that we can let patients and families know what’s happening in the science of colorectal cancer.

For the last year, Fight Colorectal Cancer staff have tracked the progress of the drug TAS-102 – an oral chemo drug currently being evaluated in clinical trials for patients with metastatic refractory colorectal cancer. At the ESMO World GI Congress on Gastrointestinal Cancer, results from the phase 3 RECOURSE trial showed that TAS-102 improved survival for colorectal cancer patients who had stopped responding to any of the existing treatment options.

About the TAS-102 Trial

The RECOURSE trial enrolled patients whose cancer continued to grow after receiving first-line and second-line treatments. These patients received either TAS-102 or a placebo. In addition, all patients received best supportive care. The trial was conducted in Japan, United States, Europe and Australia from June 2012 to December 2014.

Results of the Trial

The results of the clinical trial showed that overall survival for the patients who took the TAS-102 pill was 7.1 months; for patients who received the placebo, it was to 5.3 months. The 11-week difference between the chemotherapy drug and placebo is statistically significant.

Side effects included relatively modest leucopenia and neutropenia, which increase risk of infection, and anemia, which causes fatigue. Dr. Robert Mayer, from the Dana Farber / Harvard Cancer Center who is the US Primary Investigator for the trial commented that,

“the results from the RECOURSE study are quite encouraging and support, in an 800 patient international cohort, the previously published data from a randomized phase II study conducted in Japan.”

Implications for Colorectal Cancer Patients

Dr. Richard Goldberg from Ohio State University discussed the RECOURSE results at ESMO. He says that this new drug and these results are encouraging for several reasons:

Different from 5-FU

The drug works similarly to 5-fluorouracil (5-FU) in that it binds to DNA and stops cancer cells from dividing. Unlike 5-FU, TAS-102 also appears to affect the growth of blood vessels into tumors. Laboratory studies show that TAS-102 is active in tumors that are resistant to 5-FU and that the drug inhibits tumor growth more effectively than 5-FU in some tumors sensitive to 5-FU. This preclinical profile is therefore very promising. (Note: A preclinical profile is based off research performed in labs as opposed to on people.)

Well tolerated in patients

In addition, Dr. Goldberg commented that the patients studied in the RECOURSE trial had been heavily pretreated, with almost all having received every approved drug for treating colorectal cancer before they received TAS-102, including 5-FU, oxaliplatin, irinotecan, bevacizumab and EGFR inhibitors (cetuximab, panitumumab) for patients without a KRAS mutation. The tumors in these patients are very resistant to drugs and patients may experience symptoms due to their advanced disease that make treatment harder to tolerate. The fact that side effects of TAS-102 are mainly related to low white cell counts and anemia means that even this group of patients who’ve received nearly every drug already could tolerate these pills well, a prerequisite to getting any benefit. This toxicity profile also suggests TAS-102 may combine well with other chemotherapy or biological agents.

Patients with KRAS Mutations

TAS-102 appears to be somewhat active in patients who have tumors with the KRAS mutation (KRAS-MT). The overall survival for these patients was 6.5 months if they received TAS-102, compared to 4.9 months if they did not. While this 7-week difference is small, it suggests, as would be expected, that there is some activity regardless of KRAS status.

What’s next for TAS-102?

Drs. Leonard Saltz and Anna Varghese are conducting a phase 1 trial of TAS-102 combined with approved treatment irinotecan at Memorial Sloan Kettering Cancer Center in New York to find the most effective dose of the two drugs. Additional information about the trial can be found in clinicaltrials.gov. Dr. Saltz says that,

“we’ve been interested in this drug for a few years now and are working to integrate it into earlier lines of treatment by combining it with other standard drugs.”

Taiho Pharmaceuticals, the company producing TAS-102, plans to submit to FDA for regulatory approval toward the end of 2014. The timeline for FDA review is not publicly available; however, Taiho Pharmaceuticals and FDA discussions are ongoing. Fight Colorectal Cancer will continue working with Taiho Pharmaceuticals to get the latest information out to patients.

For Patients on Treatment NOW:

Currently, access to TAS-102 is possible only through active clinical trials. Access to TAS-102 prior to FDA approval may become available by the end of the year at certain locations – we will post updates as more information is supplied.

Our team and Medical Advisory Board members will continue to track the progress of TAS-102 and keep patients informed when this option becomes available via clinical trial.

This new drug may provide treatment options for patients in the future, but it’s not ready for prime time yet. If you have questions about your treatment, talk with your health care team. For resources on how to manage late-stage colorectal cancer, check out our Guide in the Fight.


For more information about TAS-102, check out the ESMO press release

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