New results were presented this weekend at ESMO, with data available from 15 patients. This is from the phase I part of the trial; Cantargia will proceed with the phase II part, which has a control group. In this study, nadunolimab is combined with chemotherapy. As before, the safety profile was very good with neutropenia being the main adverse event, which prophylactic G-CSF can counteract. Response figures are strong: one complete response and eight partial responses for an overall response rate (ORR) of 60%. This is an improvement over the previous readout with 12 patients and an ORR of 50%. The benchmark used by Cantargia (O'Shaughnessy et al. 2014) had an ORR of 30%. The progression-free survival (PFS) was 6.6 months, which is better than the 4.1 months of the benchmark. The overall survival has not yet been reached. The projected OS at 12.3 months is not a significant improvement over the benchmark of 11.1 months. However, the figure is just a projection based on a small number of patients (only six having died) and could improve with maturing data. One would expect a strong ORR and PFS to translate into an OS improvement (though there are exceptions).

Overall, the preliminary ORR and PFS results are strong while the overall survival is not yet mature. While we think there are no big surprises, we think the case is somewhat strengthened. We thus raise the LOA slightly to 16% (14%) and tweak the sales figures (increasing peak sales to USD500m from USD400m), but this does not affect our base case of SEK20.

We will also publish an interview with CEO Göran Forsberg where we discuss these results.

O'Shaughnessy J, Schwartzberg L, Danso MA, Miller KD, Rugo HS, Neubauer M, Robert N, Hellerstedt B, Saleh M, Richards P, Specht JM, Yardley DA, Carlson RW, Finn RS, Charpentier E, Garcia-Ribas I, Winer EP. Phase III study of iniparib plus gemcitabine and carboplatin versus gemcitabine and carboplatin in patients with metastatic triple-negative breast cancer. J Clin Oncol. 2014 Dec 1;32(34):3840-7.