Pyxis debuts next-gen cancer ADCs from under Pfizer's wing

Airplane wing
(Chaiwiwat Duangjinda/iStock/Getty Images Plus/Getty Images)

After raising a monster $152 million in a series B round last month, Pfizer darling Pyxis Oncology is ready to share more details about what it’ll be working on with all that cash.

The Cambridge, Massachusetts-based biotech is developing three antibody-drug conjugates (ADCs), namely: PYX-201, PYX-202 and PYX-203 for a range of difficult-to-treat cancers. Each therapy could be effective against a number of malignancies with similar traits.

Two of the three candidates are based off intellectual property from Pfizer, which invested in the March series B. A number of Pyxis’ executive team members are also Pfizer alums, including CEO Lara Sullivan, M.D.

“Our ability to continue to leverage Pfizer's historical knowledge of these programs, the institutional memory and an acumen they have built up over the years on ADCs continues to be available to us through these relationships—and specifically through the Pfizer Ventures position in the company as a series B investor,” Sullivan said.

Pfizer licensed PYX-201 and PYX-203 to Pyxis in exchange for an upfront payment, development- and sales-based milestone payments and tiered royalties on potential sales. The third ADC, PYX-202, was licensed from LegoChem Biosciences in 2020.

PYX-201 is intended for non-small cell lung, ovarian, breast and pancreatic cancers; PYX-202 will tackle small cell lung cancer, soft tissue sarcoma, hepatocellular carcinoma and neuroblastoma; and PYX-203 is for hematologic cancers like acute myeloid leukemia, myelodysplastic syndromes and others.

“There's still tremendous need out there for patients with cancer, and we know that cancer sometimes is simply like a moving target,” said Pyxis Chief Scientific Officer Ronald Herbst, Ph.D., in an interview. “People so frequently unfortunately do relapse.”

RELATED: After Pfizer cancer deal, Pyxis Oncology nabs a hefty $152M series B

A number of ADCs are already on the market, but the medicines can cause significant side effects and toxicity, according to Herbst. Examples of drugs in this class include Gilead’s Trodelvy and Seagen’s Adcetris.

The Pyxis approach is attempting to make the drug much more targeted to tumor activity without impacting other areas of the body. The antibody serves as a precise delivery device, rather than, say, a chemotherapy, which is more systematic.

“Here the antibody is like your postal officer delivering a package to a particular house address or a zip code,” Herbst said. Side effects happen when the toxin designed to kill the cancer comes off the antibody early on its trip to a tumor site, he explained. But Pfizer has found a way to better attach the payload in this new generation of ADCs.

Herbst said the candidates are close to entering the clinic, and the company expects to file INDs for all three throughout 2022.

After wrapping the series B, Sullivan said the company has plenty of cash to move the three assets all the way to early clinical activity readouts.

“We're not in imminent need of financing, given the robustness of the raise, but we're always evaluating all the options in terms of ensuring sufficient capital to progress the pipeline,” Sullivan said.