Read on Twitter
$ATNM story: Non-targeted high dose radiation followed by bone marrow transplant is a preferred method to treat blood cancers in patients under 55. The success of this therapy relies on the radiation dose: it needs to be high to prevent relapse/BMT rejection. This is (1/n)
exemplified by the fact that young patients who received 15ghz of radiation had 0% relapse, whereas those who received 12ghz had 25%. Non-targeted radiation at these doses is too harsh for elderly. Thus radiation+BMT is not a viable option for this age group, and they (2/n).
typically go through chemo+BMT, which has a 10% 1yr OS for r/r. $ATNM& #39;s lead asset Iomab-B is an antibody that specifically binds blood cancer and stem cells. Iomab-B carries iodine-131, a particle that emits 4 bursts of beta particles over ~16 hours. Thus, it can deliver (3/n)
radiation that generates DNA damage directly at the site of cancer, while avoiding things such as liver damage. Interestingly, Iomab-B was able to achieve 15ghz directly at the bone marrow at the tolerable dose for pts. 55+. In ph2, it achieved a 30% 1yr OS, beating SOC. It (4/n)
is now in the ph3 SIERRA trial, which is expected to release topline data in Q4. Data at 50% enrollment already has been released. In treatment arm, 78% of patients engrafted with allogeneic HCT and did not relapse after 100 days. In control arm, which used physician& #39;s (5/n)
choice, only 13% had CRs, engrafted, and did not relapse after 100 days. Readout in Q4 is for 180 day durable CR. Even if we assume all patients in control arm have a dCR, 83% of treatment arm patients would have to relapse to have a comparable efficacy. Furthermore, (6/n)
patients on treatment arm took ~30 days to receive HCT, while patients on placebo arm took 67 days, and Iomab-B shows much more rapid kinetics for blast depletion. Faster timelines correlate with higher durable response rate. Finally, Iomab-B showed significantly less AEs (7/n
compared to SOC. Imo, Iomab-B is clinically de-risked, and betting on the ph3 trial is a high EV play. Scientific rationale is strong and clinical value proven. BMT market has steadily grown in last decade, and treatment will open it up to new patient population. (8/n)
