1. Enhertu

Enhertu notched an FDA approval in December with a boxed warning for interstitial lung disease. (AstraZeneca)

Drug: Enhertu (fam-trastuzumab deruxtecan-nxki)
Companies: AstraZeneca, Daiichi Sankyo
Used for: HER2-positive breast cancer
Est. 2024 sales: $2.4 billion

After posting impressive tumor-busting results in a pivotal phase 2 trial, AstraZeneca and Daiichi Sankyo's antibody drug conjugate Enhertu raced to an FDA approval in the final days of 2019. Now, with a launch underway, those impressive results could spell blockbuster sales for the drugmakers. 

Enhertu (fam-trastuzumab deruxtecan-nxki) could secure around $2.4 billion in global sales by 2024, according to EvaluatePharma, putting it well on top of the most highly anticipated new drug launches of the year. 

AstraZeneca picked up co-marketing rights for the drug in a $6.9 billion deal with Daiichi in March 2019, shelling out a hefty sum for what could prove to be a blockbuster. Jefferies analysts argued at the time of the pickup that the addition would provide a pipeline boost for AstraZeneca with a possibility for expanded indications in the future.

The FDA approved Enhertu in late December as a treatment for patients with inoperable or metastatic HER2-positive breast cancer who have already failed on at least two other treatments in the metastatic setting. AstraZeneca and Daiichi will jointly develop and sell the drug outside of Japan, where Daiichi holds exclusive rights.

Enhertu will likely launch this month at a per-patient cost of around $13,300 per month, SVB Leerink analyst Andrew Berens, M.D., said in a note to investors after the approval. At that price, Enhertu could reach $68 million in sales in 2020, with a peak sales estimate of $2.5 billion, Berens said.

RELATED: AstraZeneca, Daiichi notch blockbuster FDA nod for breast cancer med Enhertu

Enhertu is made up of Roche's Herceptin HER2-targeted antibody and a topoisomerase I inhibitor payload and is being tested in gastric cancer as well as in non-small cell lung and colorectal cancer. 

The FDA based its approval on the phase 2 Destiny study, where Enhertu shrank tumors in 61% of patients and eliminated them completely in 6%, Daiichi said. A 97% disease control rate included patients who saw some tumor shrinkage but not enough to be considered responders. 

Destiny patients had tried a median of five prior treatments but had essentially run out of options. Patients with HER2-positive breast cancer typically receive Roche's Herceptin or Perjeta early in their treatment, and when they relapse, they can go on Kadcyla, Genentech’s HER2-targeting antibody drug conjugate.

“Since the beginning of our clinical trial program four years ago, we have focused on the opportunity to transform the treatment landscape for patients with HER2 positive metastatic breast cancer, and we are extremely proud of how quickly we delivered Enhertu to patients in the U.S., as Enhertu represents one of the fastest-developed biologics in oncology," Antoine Yver, M.D., Daiichi's global head of oncology R&D, said in a release.

Enhertu will come with a boxed label warning for interstitial lung disease and embryo-fetal toxicity after 9% of Destiny patients developed an ILD during treatment. Nearly all of the Destiny patients (99%) experienced side effects, including nausea, vomiting and low white blood cell counts. Fifteen percent stopped treatment because of side effects, the company said. 

1. Enhertu