CAR-T developer Poseida Therapeutics has put the kibosh on its IPO plans for now and is settling instead for a $142 million series C round, with more than half of the money coming from cell and gene therapy devotee Novartis.
The Big Pharma put up a $75 million equity investment in the San Diego-based company, which aims to submit IND filings and start a midphase study this year for its stable of CAR-T candidates manufactured through a nonviral process.
However, at the top of the year, Poseida had its sights set on a Nasdaq IPO, albeit for the smaller sum of $115 million. So what changed?
“This plan was initially delayed due to the government shutdown, then delayed again to refile financials that went stale during the wait,” Poseida CEO Eric Ostertag told FierceBiotech. “Throughout the course of these delays, we continued prior conversations with strategic interests, one of which was Novartis.”
One of the goals of going public was to bring the company closer to submitting its lead BCMA CAR-T therapy, P-BCMA-101, for an FDA review in multiple myeloma before the end of 2020. Now, its IPO plans have been put off until later this year, Ostertag said.
Still, Poseida’s lead therapy may face an uphill climb: Its previous results showed a 43% overall response rate at a lower dose of 456 million cells. Raising the dose to 845 million cells did push the ORR to 100%, but it’s a lackluster showing compared to Celgene and Juno’s JCARH125, with an 83% ORR at 150 million cells or more and a 79% ORR at the lowest dose of 50 million.
But Poseida's therapy has since shown a 71% ORR in a cohort of 150 million cells, from the latest data as of January 31, and an ORR of about 65% across all dose cohorts.
Currently, the autologous P-BCMA-101 is enrolling patients in a phase 2 study as an outpatient treatment, and the company plans to begin dosing before July. Poseida believes it can make headway in CAR-T safety, which remains a strong concern for the field.
The company’s tech targets younger, self-renewing T cells—dubbed stem cell memory T cells—that act slower and avoid triggering the sudden, toxic immune system activity known as cytokine storms. In addition, these memory cells have shown long life spans and have demonstrated vaccine-like responses when cancer relapses.
In preliminary results from a phase 1 study late last year, the company said P-BCMA-101 was well tolerated—with only two transient cases of mild cytokine release syndrome under grade 3, and one patient with possible neurotoxicity, all at doses lower than those the company has planned for phase 2.
Meanwhile, in its preclinical pipeline, Poseida plans to submit at least three IND filings for CAR-T therapies in late 2019 or 2020. Those include P-PSMA-101, an autologous candidate targeting PSMA-specific, castration-resistant prostate cancer cells; P-BCMA-ALLO1, an off-the-shelf therapy for relapsed or refractory multiple myeloma; and P-MUC1C-101, aimed at multiple solid tumor indications, including ovarian, breast, lung, colorectal, pancreatic and kidney cancers.
To help fund that work, the latest series C round included several new backers such as Aisling Capital Management, Pentwater Capital Management and Perceptive Advisors. Poseida’s previous investors—Longitude Capital, Malin Corporation, Vivo Capital and Boxer Capital—also participated.
Novartis, meanwhile, has been working to build out its own cell and gene therapy with the goal of leading the field and is investing in companies aimed at making CAR-T therapies safer, more efficient or potentially cheaper to produce—such as FierceMedTech Fierce 15 winner Mekonos, which aims to use small needles to inject genetic material at scale instead of viral vectors. By comparison, Poseida’s manufacturing process uses a proprietary transposase enzyme to cut and paste a genetic payload into cells’ DNA.
In February, Novartis CEO Vas Narasimhan said these types of treatments could have remarkable impacts: “These are true breakthroughs that come from a single infusion of a medicine that don’t require lifelong therapy,” he said at the company’s annual meeting.
Narasimhan has also described Novartis’ plan for a “game board” of cell and gene therapies, complemented by advanced radio-drug conjugates, that will pay off as they expand from rare diseases into broader indications.
Editor's Note: This story was updated with additional study data from Poseida.