Nick Leschly / Boston Globe, End­points News

Blue­bird bio $BLUE un­veiled its lat­est up­date on its close­ly-watched BC­MA-tar­get­ing CAR-T for mul­ti­ple myelo­ma to­day of­fer­ing a slate of sol­id ev­i­dence that demon­strates the promise that at­tract­ed Cel­gene $CELG to their am­bi­tious col­lab­o­ra­tion on this drug. But with a ri­val Chi­nese group mak­ing a splash at AS­CO this year, the biotech may be see­ing its sta­tus as the fron­trun­ner in the field start to fade a bit.

In the first new da­ta to come out since late last year, blue­bird of­fered an up­date on 18 pa­tients in four dif­fer­ent dos­ing co­horts in search of in­sights on dura­bil­i­ty, dos­ing and safe­ty for bb2121.

With 18 pa­tients evalu­able for ef­fi­ca­cy, there were 15 in what blue­bird termed ac­tive dos­ing reg­i­mens above the min­i­mum for bb2121, and all of them achieved an ob­jec­tive re­sponse. Twelve achieved a very good par­tial re­sponse to com­plete re­sponse, as­so­ci­at­ed with longer sur­vival times. And of the 4 pa­tients evalu­able for min­i­mal resid­ual dis­ease sta­tus, all were MRD neg­a­tive with on­ly a few or no myelo­ma cells in cir­cu­la­tion.

That is all ex­cel­lent.

Up un­til now, blue­bird and Cel­gene were wide­ly viewed as the lead­ers in the BC­MA field. But Nan­jing Leg­end’s da­ta out this morn­ing may well put that sta­tus in ques­tion.

I asked blue­bird CEO Nick Leschly about that over the week­end.

His re­sponse, with a smile: “We are com­plete­ly, con­struc­tive­ly para­noid no mat­ter what.”

Short trans­la­tion: Blue­bird is hap­py where they are and con­fi­dent about mov­ing to next steps as their part­ner Cel­gene lays the foun­da­tion for a ground­break­ing reg­is­tra­tional study that may well get start­ed lat­er this year. But they all know it won’t be easy or free of chal­lenges — now or in the fu­ture as ri­val ther­a­pies line up to chal­lenge them.

Da­ta from tri­als that don’t in­volve head-to-head de­signs with­in the con­struct of the same study are no­to­ri­ous­ly dif­fi­cult to com­pare. In Leg­end’s case, says Leschly, it seems ev­i­dent that the pa­tients weren’t as sick and hadn’t failed the same mul­ti­ple of drugs that blue­bird re­cruit­ed for.

That makes it “ap­ples and or­anges,” he says, adding “that doesn’t mean it isn’t great da­ta.”

All of it, notes Leschly, helps val­i­date the tar­get, while blue­bird is sat­is­fied that it has the right drug to take for­ward. Its next-gen drug, bb21217, will come up be­hind it as Cel­gene preps for the piv­otal BC­MA study to some. “It’s all go, go, go” on bb2121, says Leschly, whose of­fi­cial ti­tle is chief blue­bird.

“All these pa­tients are do­ing in­cred­i­bly well,” says the CEO about his lead ther­a­py, point­ing to par­tial re­spons­es in their study that re­flect­ed a near era­sure of can­cer. These drugs face a high bar on demon­strat­ing ef­fi­ca­cy, he adds, and bb2121 comes through with fly­ing col­ors.

Blue­bird came to AS­CO with a few things to prove. It need­ed to prove that its drug works in a broad­er num­ber of pa­tients. And it need­ed to prove that the safe­ty is­sues around cy­tokine re­lease syn­drome were man­age­able.

Blue­bird’s CEO is com­ing out of AS­CO be­liev­ing that he’s an­swered those chal­lenges.

I asked Leschly about the de­bate over the 4-1BB cos­tim­u­la­to­ry do­main its drug us­es, and the the­o­ry that it could be safer than the CD28 al­ter­na­tives on the mar­ket.

Leschly’s re­mark: he’s learned to “be care­ful of open­ing your mouth be­fore you know what you’re talk­ing about.”

The 4-1BB do­main does seem to help dura­bil­i­ty, he adds, but he’s hes­i­tant to say that it ex­tends to safe­ty at this point. It’s just too ear­ly.

Blue­bird’s ex­ecs say they still have to de­cide ex­act­ly which dose to take in­to the next phase of their study (and I pressed them on it), as they add new pa­tients and pre­pare for the piv­otal study to come.

Cel­gene is clear that they want to start en­rolling for the piv­otal study this year, says Leschly. And with 50% of the US com­mer­cial rights re­sid­ing at blue­bird, he’s ready for the next step.

Microcap biotech Seelos Therapeutics is halting enrollment of its study in spinocerebellar ataxia type 3 (also known as Machado-Joseph disease) because of “financial considerations,” and in order to focus on other studies, the company said today, adding that the pause would be temporary.

The study will continue with the patients who have already enrolled, and the data from them will be used to decide whether to continue enrolling others in the future.

Otonomy may be shutting down, but the lessons learned there will live on at another biotech working on new treatments for hearing loss.

San Francisco-based Spiral Therapeutics has bought certain assets related to three of Otonomy’s programs, ranging from data, patent rights, and know-how to inventory. That includes data around Otonomy’s twice-failed lead program, OTO-104 (Otividex), a sustained-exposure formulation of dexamethasone.