Dive Brief:
- Shares for Vir Biotechnology climbed by nearly 30% Tuesday after the company reported positive early data as well as a partnership involving an experimental drug it’s developing for prostate cancer.
- In one announcement, Vir said it has partnered with Astellas Pharma on the therapy, a “masked” T cell engager known as VIR-5500. Vir will receive $335 million in upfront and near-term payouts in the deal, and could get an additional $1.37 billion in future milestones, as well as sales royalties, if VIR-5500 eventually reaches market. Astellas will lead commercialization in the U.S. and elsewhere, though Vir has the option to co-promote the drug in the U.S. and will split profits there.
- Vir also disclosed updated results from a Phase 1 trial of VIR-5500 and said the drug was well-tolerated and exhibited “promising anti-tumor activity” in 58 participants with metastatic castration-resistant prostate cancer. The data will be presented at a medical meeting later this week. Phase 3 testing should begin next year, according to Vir.
Dive Insight:
Vir was originally known for its work against infectious diseases and, at one point, brought to market medicines for Ebola and COVID-19.
The company’s early success was short-lived, however. Its COVID drug proved ineffective in the face of newer viral variants. Vir switched CEOs in 2023 and, under new leadership, restructured and shifted its primary research focus towards cancer.
Vir still has a candidate in late-stage testing for hepatitis D, and some preclinical work with the Gates Foundation on HIV. But the bulk of its pipeline involves a group of “T cell engagers” — antibody drugs that bind to targets on immune cells and cancerous ones — that it acquired through a deal with the French pharmaceutical firm Sanofi.
T-cell engagers have shown promise in treating certain cancers, but have struggled against solid tumors. They can also cause an overactive immune response known as cytokine release syndrome, requiring drugmakers to dial back dosing at the expense of greater efficacy.
One way drugmakers are attempting to bypass these issues is by “masking” drugs from the immune system until they can reach a tumor. VIR-5500, which Vir gained from Sanofi, is one example.
Vir’s Phase 1 study is evaluating VIR-5500 as a monotherapy and primarily evaluating safety, though the company is also measuring the drug’s ability to lower levels of prostate-specific antigens, a marker indicative of a treatment benefit in prostate cancer.
According to Vir, 14 of the 17 participants in the highest-dose cohorts had at least a 50% decline in PSA levels, and nine of them had a 90% reduction. Cytokine release syndrome occurred in half of treated study recruits, but were only judged as mild in severity.
In a Tuesday note to clients, Leerink analyst Roanna Ruiz wrote that the results position VIR-5500 “as a potential best-in-class PSMA T-cell engager with a differentiated safety advantage” over competitors like Janux Therapeutics. The results, combined with the deal, “validate” Vir’s oncology work, she added.
