Aptose Biosciences Inc (APTO)

[dcaf7]

Some thoughts on today's news.
1. I don't buy their explanation on tuspetinib profile. They say that tuspetinib simultaneously suppresses a small suite of kinase-driven pathways critical for leukemogenesis. Consequently, tuspetinib achieves clinical responses at lower exposures with less overall suppression of each pathway. Problem is that at higher dose and higher exposure you would expect even better efficacy. But you don't see it. 80 mg dose works better than 120 mg and 160 mg. You can argue that these three dose cohorts have patients with different mutation profiles. Possible, but why Aptose don't show us how different they are? My explanation is that at higher doses Tusp inhibits something that it is not suppose to inhibit, partially neutralizing positive effect.
2. A new response at 40 mg dose is most likely a PR. They would mention if it was a CR.
3. Noticed in their last presentation that cRR in TP53mut patients is now 33%. It was 25% in previous presentation. Thought, they have more responses. It turned out, they have less patients, 3 instead of 4. CRR of 33% is cool. Almost guaranteed approval.