NuCana plans $115M IPO to test retooled chemotherapies

NuCana has filed to raise $115 million in a Nasdaq IPO. The anticipated haul will fund late-phase trials of NuCana’s reformulated cancer candidates, including a version of Eli Lilly’s Gemzar it hopes will supplant the veteran chemotherapy in some indications.

Edinburgh, U.K.-based NuCana has built its pipeline upon the same phosphoramidate chemistry approach that underpins Gilead’s hepatitis C blockbuster Sovaldi. NuCana has used the approach to add a phosphate group protected by groupings of aryl, ester and amino acids to existing drugs. In doing so, NuCana thinks it has created drugs free from the membrane transport, activation and breakdown issues that render cancers resistant to the products they are based on.

NuCana has tested this idea in the clutch of early-phase trials. Two or more lines of Acelarin, NuCana’s version of Gemzar, triggered partial responses in five of the 49 advanced solid tumor patients evaluated in phase 1. About four-fifths of subjects had either a partial response or stable disease, a result NuCana took heart from given the patients were progressing after multiple lines of treatment before starting on Acelarin.

An interim look at Acelarin in combination with carboplatin in a phase 1b ovarian cancer trial painted a similar picture. Among the 23 evaluable patients, 17 of whom were platinum refractory or resistant, one had a complete response and eight had partial responses. Factoring in the subjects who had stable disease, the disease control rate came in at 96%.

NuCana plans to report full results from the phase 1b later this year. If the IPO goes to plan, that will mark the start of a busy period for NuCana. The phase 1b data could position NuCana to move that combination into phase 3 next year. A phase 3 biliary cancer trial of the combination is also slated to start in 2018. And NuCana expects to post data from two trials in platinum-resistant ovarian cancer, a phase 2 monotherapy study and an exploratory Avastin combination trial.  

The Scottish biotech is advancing Acelarin in parallel to NUC-3373, a reworking of 5-FU. NuCana is aiming to start positioning NUC-3373 as an improvement on 5-FU with the publication of interim phase 1 solid tumor data later this year, and, more conclusively, by testing the candidate in phase 3 colorectal cancer and phase 2 breast cancer trials in 2018.

That plan is predicated on NuCana pulling off the IPO. The firm was down to the last $16 million of its $57 million series B by the end of June.