Amphivena Therapeutics Inc., of South San Francisco, closed on a $62 million series C that will allow the company to continue its study of selective myeloid-derived suppressor cell (MDSC) removal in hematologic and solid cancers and to advance its lead candidate, AMV-564, a bivalent, bispecific T-cell engager in a phase I trial for treating patients with relapsed/refractory acute myeloid leukemia and myelodysplastic syndromes.

"We believe that AMV-564 is selective due to the bivalency of the molecule – it has higher affinity binding to clustered CD33 on activated myeloid cells such as leukemic blasts and MDSCs," Jeanmarie Guenot, Amphivena's CEO and president, told BioWorld. "The selective binding to MDSCs is important since this is a plastic population of myeloid cells with no good antigen to target. We also eliminate the population rather than block pathways."

AMV-564, which spares normal myeloid cells, such as neutrophils and monocytes, has an excellent safety profile that enables competitive approaches, such as combination therapy, she added.

The phase I is an open-label, multicenter, dose-escalation study, with continuous infusion of AMV-564 at increasing dose levels. Primary outcomes include measuring all adverse events and serious adverse events for safety and tolerability and, for the expansion stage, measuring its efficacy and remission rate. The estimated study completion date is June 2020.

There is another phase I trial for AMV-564 in the works and it is currently enrolling adult patients with intermediate- or high-risk myelodysplastic syndromes. The interventional, non-randomized, sequential assignment, open-label study got underway in June 2018 and has an estimated completion date of May 2020. The dose escalation (3+3 design) is up to a maximum tolerated dose level and will be tested in a 14-day continuous intravenous infusion regimen. Its dose-expansion arm will expand at the maximum tolerated dose level or a lower dose level to obtain initial estimates of response rates and additional safety information. It, too, is a 14-day continuous intravenous infusion regimen. Primary outcomes include evaluating the dose-limiting toxicity through 28 days and an overall response rate on the dose expansion.

The company has now raised $88.5 million in its series A, B and C financings. In 2013, Amphivena, originally established in Wilmington, Del., received $19.5 million in its series A round that was from MPM Capital and Aeris Capital – both of which were funded by Johnson & Johnson – and also from Heidelberg, Germany-based Affimed Therapeutics AG. For its series B, Tekla Capital Management LLC joined with the founding investors. The series C round was co-led by Nanodimension and Qiming Venture Partners USA, with new investors Clough Capital, Aju IB, Korys Merieux, Kaitai Capital, Industrial Investors, Nawton Ltd. and insiders MPM Capital, funds managed by Tekla and Franklin Berger.

Guenot said the company will expand its staffing level with the funding.

The company name is derived from amphisbaena, a mythical serpent or winged creature having two heads, one at each end of its body, and refers to AMV-564's bivalent, bispecific nature.

In late November 2017, the FDA granted orphan drug designation to AMV-564. A year and a half later, Amphivena appointed Victoria Smith as its chief scientific officer. Smith joined the company from Gilead Sciences Inc., where she led the biologics and target biology group that focused on drug discovery and translational research in oncology. At that time, the company also brought Peter Van Vlasselaer to the board as an independent executive chairman. Van Vlasselaer is a founder and former president and CEO of Armo Biosciences, which was acquired by Eli Lilly and Co. last year for about $1.6 billion in an all-cash transaction intended to bolster the latter's immune-oncology program. (See BioWorld, May 11, 2018.)

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