The table below compares nimotuzumab (nimo) + irinotecan (N-Mab + Iri) data against results obtained from an integrated analysis of four trials of patients treated with Erbitux (cetuximab) + irinotecan (C-Mab + Iri) following irinotecan failure in a similar patient population:



YM BioSciences (YMI) announced preliminary results from a Phase 2 study of nimo in patients with irinotecan-refractory, metastatic colorectal cancer (mCRC). The data are based on 58 evaluable patients of the 61 enrolled in the trial. The prospective primary endpoint in the trial is objective tumour response rate (RR) with secondary endpoints that include overall survival, the rate and duration of stable disease, and progression free survival (PFS). The RR was 3.4% while the disease control rate reported was 50%, consisting of 27 patients with stable disease and two patients with partial response as determined using RECIST criteria. Median PFS was 12 weeks. Overall survival (Kaplan-Meier) in the evaluable patients was 9.3 months.

Tissue samples from 17 patients were available for kRas analysis. About 30% of the patients had mutated kRAS. PFS of 12 weeks was observed in patients with the mutation and 18 weeks in patients with wild type. These results are in line with expectations since the kRAS mutation is a well known impediment to EGFR antibody effectiveness. Also, companies such as Clarient (CLRT) have developed screening tests to detect the mutation and select patiients with the wild type genetic profile who are more likely to benefit from EGFR antibody therapy. In this trial, nimo continued to demonstrate a best-in-class safety profile with only 22% of patients (15) reporting a rash, all of which was graded I/II. In contrast, Grade I/II rash was reported in 80% and Grade III/IV in 9.4% of patients in the cetuximab/irinotecan trial known as BOND 1.

The Company intends to file for registration trials in 2008 for patients with non small cell lung cancer and for those with brain metastases because of encouraging Phase 2 results in those indications and since they require shorter development times than CRC trials would require. Shares of YM Bio are down by 18% during intraday trading on heavy volume as investors hoping for blockbuster results in the mCRC trial were disappointed; although the Company still intends to pursue commercialization for this indication at a later date. However, I believe shares of YM Bio will rebound over the remainder of the year as more data points are released on nimo to support near-term commercialization for other indications.