AZN Wins FDA Nod for Expanded Use of Rare Disease Drug, Koselugo

AstraZeneca AZN announced that the FDA has approved its oral, selective MEK inhibitor, Koselugo (selumetinib), for expanded use. The drug is now indicated to treat symptomatic, inoperable plexiform neurofibromas (PN) in adult patients with neurofibromatosis type 1 (NF1) in the United States.

Koselugo’s label was also recently expanded to include this indication in the EU, Japan, and some other countries, with additional regulatory reviews currently ongoing. Koselugo is already approved to treat certain pediatric patients with NF1 who have symptomatic, inoperable PN in the United States, the EU, Japan, China and other countries.

In the United States, a granule formulation of Koselugo was also recently approved by the FDA for young children aged one year and older with NF1 PN.

Rationale Behind the FDA Nod for AZN’s Koselugo Expanded Use

The FDA approval of the label expansion of AstraZeneca’s Koselugo to treat adult patients with NF1 who have symptomatic, inoperable PN was backed by data from the global phase III KOMET study. In the primary endpoint analysis of the KOMET study, treatment with Koselugo demonstrated a statistically significant and clinically meaningful overall response rate (ORR) of 20% compared to 5% with placebo by cycle 16.

ORR represents the proportion of patients who achieve either a confirmed complete response (tumor disappearance) or a partial response (a tumor volume reduction of at least 20%).

Additionally, approximately 86% of patients receiving Koselugo therapy achieved an observed duration of response of at least 6 months. Year to date, shares of AstraZeneca have rallied 35.3% compared with the industry’s growth of 15.8%.

NF1 is a rare, progressive genetic disorder typically identified in early childhood but often advancing into adulthood, with the potential to affect multiple organ systems. Per AZN, up to half of individuals with NF1 develop non-cancerous PN in the brain, spinal cord, or nerves, which may emerge later in life and grow substantially, causing disfigurement, pain, and various functional impairments.

Koselugo enjoys the FDA’s Orphan Drug designation in the United States, the EU, Japan and other countries for the treatment of NF1.

AstraZeneca has a collaboration deal with Merck MRK for Koselugo. In the third-quarter 2025 earnings release, AstraZeneca announced modifying the Koselugo partnership with Merck, having assumed full global responsibility for the drug’s costs, revenues and profits. Previously, AZN and MRK split Koselugo’s pre-tax profits and losses equally. Apart from Koselugo, AstraZeneca and Merck have a collaboration deal for Lynparza, which is ongoing.

AstraZeneca PLC Price and Consensus

AstraZeneca PLC price-consensus-chart | AstraZeneca PLC Quote

AZN's Zacks Rank & Stocks to Consider

AstraZeneca currently carries a Zacks Rank #3 (Hold).

Some better-ranked stocks in the biotech sector include Editas Medicine EDIT and ADMA Biologics ADMA, each carrying a Zacks Rank #2 (Buy) at present. You can see the complete list of today’s Zacks #1 Rank (Strong Buy) stocks here.

In the past 60 days, estimates for Editas Medicine’s loss per share have narrowed from $2.12 to $2.06 for 2025. During the same time, loss per share estimates for 2026 have widened from $1.02 to $1.05. Year to date, shares of EDIT have rallied 94.5%.

Editas Medicine’searnings beat estimates in two of the trailing four quarters and missed the mark on the other two occasions, delivering an average negative surprise of 13.17%.

In the past 60 days, estimates for ADMA Biologics’ earnings per share have increased from 57 cents to 58 cents for 2025. During the same time, earnings per share estimates for 2026 have improved from 88 cents to 90 cents. Year to date, shares of ADMA have lost 4.6%.

ADMA Biologics’ earnings beat estimates in one of the trailing four quarters, matched once, and missed the same on the remaining two occasions, with the average negative surprise being 3.01%.

Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report

This article originally published on Zacks Investment Research (zacks.com).

Zacks Investment Research