Interesting post nsa122. Thanks for bringing to the attention of CoBF.
My high level understanding of bluebird's bear thesis is the following -
1. Their gene therapy LentiGlobin (bb1111) being tested for Sickle Cell has 2 patients develop AML and MDS and risk severe of side effect derailing the drug or lowering estimated revenue even if approved
2. Marketing for another approved drug Zynteglo suspended. It uses the same underlying technology (LentiGolbin) for thalassemia.
3. Their entire lentivirus based gene therapy pipeline is compromised as per analysts (see -
https://finance.yahoo.com/news/don-t-bargain-hunting-bluebird-003840593.html)
4. Their other drug for Sickle Cell (BCL11A sh RNA) now is under competition from Vertex's competitor drug (based on crisper)
5. Bluebirds CAR-T is an important asset. But Ide-cel (tie up with BMS) has run into manufacturing issues with FDA delaying its approval.
I think the bear thesis has some legs but there is also some potential for mispricing due to the above information. Here are some thoughts -
1. For LentiGlobin in Sickle cell it is quite possible that the 2 patients would have developed these cancers as the disease itself is linked to higher incidence of cancer. (see -
https://www.healio.com/news/hematology-oncology/20170920/sickle-cell-disease-doubles-risk-for-leukemia)
2. Drug companies frequently suspend clinical trials due to unrelated adverse events showing up in their cohort (clinical trial participants). An example is Astrazeneca's covid vaccine that was halted due to adverse effect with turned out to be unrelated to their vaccine.
3. Bluebird is still the leader as compared to Vertex (see -
https://www.evaluate.com/vantage/articles/news/trial-results/bluebirds-early-stage-sickle-cell-gene-therapy-shows-promise) when it comes to curing severe Sickle Cell via targeting BCL11A gene.
4. The Vertex Crisper based (bleeding edge technology) for Sickle Cell targeting BCL11A gene has more uncertainty due to many unknowns. Crisper is very new tech that still has no approved drug on the market. Also it has been shown to have non-specific off-target mutagenesis (cutting off unrelated parts in your DNA) which can lead to severe side effects. This risk is not fully taken into account so far. Bluebird's tech also targets BCL11A but via shRNA. This tech has been around for some time now and has drugs approved (see -
https://www.genengnews.com/resources/tutorial/a-new-lease-on-life-for-shrna/).
For the above reasons this may well indeed be a temporary set of hurdles for bluebird. If anyone here has more insights I am missing, I will appreciate their input.