Nektar CEO slams Eli Lilly's 'egregious error,' laments lost time for rezpeg

Nektar Therapeutics CEO Howard Robin is not backing down after the biotech accused Eli Lilly of botching the math behind the formerly partnered immunology asset rezpeg. 

“It’s, in my mind, an egregious error,” Robin said during Nektar's second-quarter earnings call, which was held Tuesday afternoon—one day after the biotech filed suit against the Big Pharma in California court.  

For those not yet familiar with the quickly unfolding saga, here’s the breakdown. Monday, Nektar accused Eli Lilly of incorrectly analyzing phase 1b trial results for rezpegaldesleukin (rezpeg) in patients with atopic dermatitis (eczema) and psoriasis. Earlier this year—in wake of the analysis—the Big Pharma handed back rights to the drug, which Nektar now fully owns.

But after getting the asset back in hand, Nektar reviewed the data and found errors that misrepresented rezpeg's potential efficacy. While Lilly said the data showed a 17% placebo-adjusted mean improvement on the eczema scale in atopic dermatitis, Nektar's analysis put that at 36%. Similarly, the proportion of people on the high dose who experienced a 75% or greater improvement increased from 29% in Lilly’s analysis to 41% in Nektar’s redo. 

In psoriasis, Lilly found that the proportion of patients who achieved a 75% or greater improvement was 11%. Nektar says that number is actually 21%. 

According to Nektar, Lilly’s atopic dermatitis analysis “miscalculated for the validated 72-point EASI scoring system and excluded certain available patient data at the time of the interim.” The biotech added that the psoriasis efficacy endpoints “were miscalculated for the validated 72-point PASI scoring system.” Nektar said Monday that Lilly has confirmed the analytical errors in writing.

Nektar then issued a press release Monday with the new analysis and also moved to sue Lilly, according to a complaint filed in the U.S. District Court for the Northern District of California. In the lawsuit, Nektar accuses Lilly of losing interest in the rezpeg partnership after buying another company—Dermira—with a competing drug candidate and then executing "on a scheme to ensure that rezpeg would never succeed."

“We take this lawsuit very seriously—it’s significant, it’s substantial,” Robin said during the call. “If you look at the development of rezpeg, rezpeg could have likely been in a phase 2 study in atopic dermatitis a year ago, a year and a half ago.”

Robin wouldn’t comment further on the lawsuit, citing the ongoing litigation.

According to Nektar, Lilly shared the inaccurate analyses from the phase 1b clinical trials that tested the IL-2 conjugate in patients with eczema and psoriasis at the European Academy of Dermatology and Venereology meeting last fall. Lilly then returned rezpeg rights to Nektar, along with the raw clinical data, in April. That was the first time Nektar was able to see the complete patient data set. Upon review, Nektar hired an independent statistical firm to analyze the raw data. The independent assessment turned up the new efficacy results.  

When asked on the earnings call whether there was a precedent for this type of situation, the Nektar CEO said he didn’t know of any instance of “companies making this kind of a calculation error.” The calculations were done in-house by Lilly, not contracted out to a CRO. 

In a statement given to Fierce Biotech on Tuesday morning, Lilly defended the decision to drop rezpeg, which the companies had initially developed in lupus. 

"The rezpeg phase 2 trial did not meet its primary endpoints for the lead indication [systemic lupus erythematosus] and we therefore made the data-driven decision not to further develop the asset," Lilly said. "Our decision to terminate the collaboration with Nektar was based on the totality of evidence related to the asset, including these phase 2 SLE results."

The statement continued: "Lilly complied and continues to comply with its obligations under the collaboration agreement with Nektar and is committed to the highest scientific and research standards in the development of therapies to advance patient care."

As for rezpeg’s path forward, Robin said the company is enthusiastic about moving into a phase 2 for eczema. The company intends to hold an investor meeting soon to present additional data from the eczema study for the 36-week follow-up period and share the study design for a phase 2b trial. Initial data from the trial is expected in the first half of 2025.

Robin said the company is hopeful about testing rezpeg in other indications—including lupus.

“I think it worked fairly well in lupus and there are data correction there that also we're analyzing,” the CEO said.

Nektar's shares have risen 92% over the last five days, from 51 cents at market open last Wednesday to $1 at market close this Tuesday.

The company also saw an immuno-oncology partnership with Bristol Myers Squibb implode last year, leading to layoffs and a reorganization. Hopes had shifted to the Lilly collaboration and the three potential indications, Robin said during the company’s presentation at the J.P. Morgan Healthcare Conference in January.