NuCana on the Rocks After Key Asset Fails in Biliary Tract Cancer

NuCana's biliary tract cancer study halted.

NuCana's biliary tract cancer study halted. 

Shares of NuCana have plunged more than 57% in premarket trading after the company announced its Phase III biliary tract cancer study with Acelarin halted following an interim futility analysis.

Scotland-based NuCana reported that an Independent Data Monitoring Committee recommended discontinuing the study of Acelarin (NUC-1031) plus cisplatin in colorectal cancer following the assessment conducted at an interim analysis.

Acelarin is one of NuCana’s ProTide drugs that Founder and Chief Executive Officer Hugh S. Griffith called a “clever bit of chemistry” in a previous interview with BioSpace. Griffith explained that Acelarin is a transformation of Eli Lilly’s old drug Gemzar. Griffith had high hopes that the Acelarin treatment could prove to be a treatment option for biliary tract cancer, which is a notoriously difficult cancer to treat.

What does NuCana Said About Biliary Tract Cancer Study

In its announcement on March 3, NuCana said the interim analysis revealed a higher objective response rate in the biliary tract cancer patients who received Acelarin plus cisplatin. However, it did not translate into an overall survival benefit. The Independent Data Monitoring Committee determined that the Acelarin arm was unlikely to achieve the primary endpoint of demonstrating at least a 2.2-month improvement in overall survival compared to the standard of care, which is Gemzar (gemcitabine) plus cisplatin.

Griffith called the news of the interim analysis “disappointing.” He noted that the failure “highlights the challenges associated with developing new medicines for patients with biliary tract cancer.” He said NuCana would review the data to determine the potential development pathways for Acelarin.

In earlier clinical studies, Acelarin plus cisplatin posted positive data, including the doubling of response rate in these patients compared to gemcitabine plus cisplatin. In the previous ABC-08 study of first-line patients with biliary tract cancer, Acelarin plus cisplatin achieved an objective response rate of 44%. The company reported a favorable 26% gained from gemcitabine plus cisplatin. That data had fueled NuCana’s hopes that Acelarin could become a standard of care medication for this disease. That data led to the U.S. Food and Drug Administration’s granting of Fast Track designation to Acelarin last year for biliary tract cancer.

Emphasizing the difficulties of treating biliary tract cancer, Jennifer J. Knox, M.D., a professor of medicine at the University of Toronto and chief investigator of the NuTide:121 study assessing Acelarin, said biliary tract cancer includes a group of tumors that is difficult to treat.

“Developing effective therapies in this setting is extremely challenging. I, along with the other NuTide:121 investigators, am dedicated to developing better treatment options for patients with biliary tract cancer. While the outcome of NuTide:121 is disappointing, it will not diminish our determination to address the unmet needs of these patients,” Knox said in a statement.

While NuCana stumbled with Acelarin, Griffith noted the company has other ProTides aimed at different types of cancer. One of those, NUC-3373, will begin a Phase III study in colorectal cancer later this year. Dosing is expected to start in that study in the second half of 2022. Griffith said NUC-3373 generates promising data in the Phase Ib/II colorectal cancer study. The company is conducting other studies to determine additional solid tumors the ProTide can target.

NUC-7738 is entering Phase II development in solid tumors and lymphoma patients with data readouts later this year.

Griffith concluded that the company is in a “robust financial position” that will continue focusing on its strategy and anticipate the generation of essential data readouts from ongoing studies.

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