MBIO Soars on Orphan Drug Nod for Investigational Brain Cancer Therapy

Shares of Mustang Bio MBIO skyrocketed 180.7% on Monday after the company announced that the FDA granted Orphan Drug designation to its investigational candidate, MB-101, which is being developed for treating recurrent diffuse and anaplastic astrocytoma (astrocytomas) and glioblastoma (GBM). These are both rare brain cancer indications.

MBIO’s MB-101, an IL13Rα2-targeted CAR-T cell immunotherapy, is being evaluated in a phase I study for treating recurrent/refractory GBM patients.

Benefits of the FDA’s Orphan Drug Status for MBIO’s MB-101

The FDA grants the Orphan Drug designation to drugs and biologics developed for the treatment, diagnosis, or prevention of rare diseases affecting fewer than 200,000 people in the United States. This designation is meant to encourage innovation in areas of unmet medical need.

Drugs with Orphan status are eligible for various incentives, including tax credits for clinical study costs and waivers of prescription drug user fees. Additionally, they receive seven years of market exclusivity for the designated condition, separate from any patent protection.

Year to date, MBIO shares have plunged 62.3% compared with the industry’s 1.9% decline.

Last year, Mustang Bio had also secured the FDA’s Orphan Drug status for another candidate, MB-108, an HSV-1 oncolytic virus, for the treatment of malignant glioma. The candidate is currently being evaluated in a separate phase I study for the GBM indication.

Both MB-101 and MB-108 have been well-tolerated by GBM patients in their respective phase I studies. Notably, 50% of the patients treated with MB-101 achieved stable disease or better, with two partial responses and two complete responses lasting 7.5 and 66+ months, respectively.

Additionally, Mustang Bio is looking to initiate a phase I study of a novel combination of MB-101 and MB-108 (referred to as MB-109) for the treatment of patients with IL13Rα2+ relapsed or refractory GBM and high-grade astrocytoma in the first quarter of 2026. Per preclinical data, the use of this combo therapy has the potential to optimize clinical results for the difficult-to-treat brain cancer indication.

However, the continuation of the MB-109 development program for recurrent GBM and high-grade astrocytomas depends on securing additional financing and/or entering into a strategic partnership.

Mustang Bio’s clinical-stage pipeline comprises another CAR-T cell therapy targeting CD20, MB-106, for which a phase I study is planned in the first quarter of 2026 to treat hematologic malignancies and autoimmune diseases.

Mustang Bio, Inc. Price and Consensus

Mustang Bio, Inc. price-consensus-chart | Mustang Bio, Inc. Quote

MBIO’s Zacks Rank and Stocks to Consider

Mustang Bio currently carries a Zacks Rank #3 (Hold).

Some better-ranked stocks in the biotech sector are Immunocore IMCR, Verona Pharma VRNA and Bayer BAYRY. While IMCR and VRNA sport a Zacks Rank #1 (Strong Buy) each, BAYRY carries a Zacks Rank #2 (Buy) at present. You can see the complete list of today’s Zacks #1 Rank stocks here.

In the past 90 days, loss per share estimates for Immunocore’s 2025 have improved from $1.44 to 70 cents. Loss per share estimates for 2026 have narrowed from $1.45 to $1.08 during the same period. IMCR stock has gained 9.9% year to date.

Immunocore’s earnings beat estimates in three of the trailing four quarters and missed the mark once, delivering an average surprise of 76.18%.

In the past 90 days, Verona Pharma’s bottom-line estimates for 2025 have significantly improved from a loss of 7 cents per share to earnings of 22 cents. During the same timeframe, estimates for 2026 earnings per share have improved from $2.21 to $2.88. VRNA stock has soared 96.4% so far this year.

Verona Pharma’s earnings beat estimates in one of the trailing four quarters and missed the mark on the other three occasions, delivering an average negative surprise of 6.76%.

BAYRY’s 2025 earnings per share estimate has increased from $1.19 to $1.27 for 2025 over the past 90 days, while that for 2026 has gone up from $1.28 to $1.34 over the same timeframe. Year to date, shares of Bayer have surged 56.6%.

BAYRY’s earnings beat estimates in one of the trailing four quarters, matched twice and missed on the remaining occasion, the average negative surprise being 13.91%.

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