I wrote about the drug amrubicin in a prior post, after it demonstrated provocative activity in clinical trials out of Japan that were presented at ASCO 2007. Additional result on amrubicin in previously treated ED-SCLC were presented at a NYC meeting last week, and it's continued to look very encouraging in a clinical setting in which we could really use more options.

As described in a press release, the trial in question was a randomized phase II study that enrolled patients with ED-SCLC who had initially responded to platinum-based chemo (standard treatment) and then developed evidence of progression a minimum of 90 days after completing first-line treatment (sensitive relapse, as described in a prior post). Patients enrolled were randomized in a 2:1 fashion to amrubicin, given IV for 3 days every 21 days, or the FDA-approved standard drug, topotecan (Hycamtin), given IV over 5 days, respectively.

Although the results are based on only 42 patients thus far (28 receiving amrubicin, 14 receiving topotecan), the findings are striking. First, the response rate with amrubicin is 11/28 (39%) with amrubicin, not quite the 50+% rate seen in the earlier Japanese trials, but very encouraging for previously treated patients (including two complete responses, very unexpected in the recurrent SCLC setting). Second, while it might be the case that these are more "cherry-picked" patients than you'd generally see (selection bias), the topotecan arm has demonstrated responses in 2/14 (14%) patients thus far (neither a complete response), which is perfectly fine, not underperforming and about what you'd expect.

The numbers are small and it's still early, but it was also reported that there is a median survival difference of over two months favoring amrubicin, a 33% improvement.

It's early, but amrubicin has been about the most promising light in the SCLC field, so it's great to see that it's still holding up to additional scrutiny. The big test, however, will be the phase III randomized trial in patients with recurrent ED-SCLC and either sensitive or resistant relapse. This trial is just getting off the ground and will enroll 480 patients randomized to either amrubicin or current standard Hycamtin, and it will look for a significant difference in overall survival. We'll anxiously await the results of that trial and others. Information about clinical trials with amrubicin in lung cancer is here.