CHICA­GO — Bris­tol-My­ers Squibb $BMY has gone all in on Nek­tar’s $NK­TR ap­proach to amp­ing up their check­point strat­e­gy, part­ner­ing on NK­TR-214. But in­stead of tak­ing a bow at #AS­CO18 on pos­i­tive da­ta, re­searchers spent the week­end ex­plain­ing why their lat­est da­ta read­out from a small study shouldn’t be cause for pan­ic.

It’s not what they were look­ing for, to put it mild­ly.

Mary Tagli­a­fer­ri

Un­like most of the more close­ly-watched pro­grams here at AS­CO, the re­searchers in­volved nev­er of­fered a pre­view of the da­ta that came out Sat­ur­day evening. And that was a se­ri­ous mis­step, par­tic­u­lar­ly as the re­porters cov­er­ing this ses­sion strug­gled to fig­ure out what was be­ing re­port­ed — and what it meant.

As it hap­pens, in­ves­ti­ga­tors ex­e­cut­ed a two-stage tri­al process, sign­ing up a small group of pa­tients to test the drug in dif­fer­ent can­cer types, then mov­ing on to the next stage with a new group of re­cruits. Do­ing that, says Mary Tagli­a­fer­ri, the chief med­ical of­fi­cer at Nek­tar, meshed well with their strat­e­gy for jump­ing in­to late-stage stud­ies as they com­mu­ni­cat­ed with reg­u­la­tors.

“The goal,” she tells me, “was al­ways to as­sess mov­ing very quick­ly in­to Phase III.”

In­vestors, though, weren’t hap­py with the way this all came down, and they bolt­ed when the mar­ket opened, with Nek­tar’s stock plung­ing a sting­ing 32% — ex­act­ly the kind of rout that Bris­tol-My­ers (down 1.6%) doesn’t need right now as it tries to re­store con­fi­dence in its pipeline. And it kept get­ting worse lat­er in the day, with shares down 42%.

Here’s what Nek­tar has found so far.

In their melanoma project, re­searchers saw that 11 of 13 pa­tients treat­ed with a com­bi­na­tion of Op­di­vo and NK­TR-214 re­spond­ed in round 1 — which is out­stand­ing. But, when they added 15 more pa­tients, they on­ly boost­ed their re­sponse rate by 3 pa­tients. And 3 out of 15 is not out­stand­ing.

In kid­ney can­cer, the step one re­sponse rate of 64% was fol­lowed up with an over­all step 2 rate of 46%.

In­vestors hate to see a falling re­sponse rate, for any rea­son, as it in­di­cates a prob­lem that can se­ri­ous­ly af­fect a can­cer drug’s longterm fi­nan­cial suc­cess.

Twit­ter’s day-trad­ing crew picked it up from there, with all sorts of #AS­CO18 chat­ter about a tri­al dis­as­ter in the mak­ing. And as of­ten hap­pens, Twit­ter is not a great source of re­al-time in­for­ma­tion, par­tic­u­lar­ly when the com­pa­nies failed to ex­plain what the num­bers meant with an­a­lysts.

In the fol­lowup dis­cus­sion, though, Tagli­a­fer­ri of­fered the ra­tio­nale that it’s ear­ly days for the sec­ond batch­es of pa­tients and they ex­pect to see more re­spons­es with time. And they have rea­son to be­lieve that, af­ter track­ing a 46% ORR in RCC at SITC that has now grown to 71% at AS­CO.

“You’ll see the ORR go­ing up,” says Tagli­a­fer­ri, as they have a chance to col­lect mul­ti­ple scans on the sec­ond-stage pa­tients. “It s a lit­tle frus­trat­ing that peo­ple aren’t un­der­stand­ing that.”

Al­so im­por­tant, they say, is clear ev­i­dence that the com­bi­na­tion of NK­TR-214 is do­ing what they re­al­ly want­ed: Spark­ing re­spons­es in PD-L1 neg­a­tive tu­mors where Op­di­vo is not suc­cess­ful. If that all plays out in the am­bi­tious piv­otal pro­gram now un­der­way, it will eas­i­ly jus­ti­fy Bris­tol-My­ers’ record $3.6 bil­lion wa­ger.

If not….

In melanoma, re­searchers saw 5 out of 11 PD-L1 neg­a­tive pa­tients re­spond; in kid­ney can­cer it was 9 out of 17, or 53%. Those num­bers are fine.

Right now, though, they’ve cre­at­ed an at­mos­phere of doubt that will make every turn of da­ta a cat­a­lyst for the gam­blers now lin­ing up their bets for and against the com­bi­na­tion. That will ei­ther help or hurt these com­pa­nies, which are now bet­ting heav­i­ly that step 2 will ul­ti­mate­ly play out in their fa­vor.

We’ll find out more at the next SITC con­fer­ence in No­vem­ber, Tagli­a­fer­ri adds, with ab­stracts due in Au­gust.

My take on the Nek­tar da­ta is that it just be­came the biggest bat­tle­ground in biotech. Ei­ther you be­lieve 1) the new pa­tients from the phase two ex­pan­sions will turn in­to re­spons­es with time or 2) phase one was a low n mi­rage. We’ll on­ly know with time.

— Brad Lon­car (@brad­lon­car) June 3, 2018

89bio said its drug was better than placebo at lessening fibrosis without worsening nonalcoholic steatohepatitis, or NASH, in two of three dose groups.

The San Francisco biotech said it thinks the Phase IIb data pave the way for a potential Phase III, following in the footsteps of another biotech in its drug class, Akero Therapeutics. To fund a late-stage study, CEO Rohan Palekar told Endpoints News 89bio “would need to raise additional capital,” with the company having about $188 million at the end of last year.