# Merck, Daiichi pull lung cancer filing after FDA pushback deals another blow to $4B deal

> **Open Intelligence Dossier** · First detected: 2026-09-28 16:40 UTC · Category: Business

## Executive Summary
Merck and Daiichi Sankyo have withdrawn their FDA application for a lung cancer therapy following regulatory pushback, impacting a $4 billion partnership.

## Intelligence Brief
Merck and Daiichi Sankyo have voluntarily withdrawn their Biologics License Application (BLA) for ifinatamab deruxtecan, a B7-H3 antibody-drug conjugate (ADC). The filing was intended for the treatment of patients with previously treated extensive-stage small cell lung cancer (SCLC). This decision follows pushback from the U.S. Food and Drug Administration (FDA), leading the two pharmaceutical companies to scrap the application for the lung cancer therapy. The withdrawal represents a significant regulatory setback for the partnered development effort targeting this specific oncology indication. Coverage of the withdrawal has been reported by several industry and financial outlets.


Fierce Biotech highlights that the FDA pushback deals another blow to a $4 billion deal between the two firms. Reuters reports that this is the second partnered cancer therapy application to be pulled by Merck and Daiichi in the United States. Endpoints News and OncLive have specifically identified the drug as an ADC targeting B7-H3 and confirmed the voluntary nature of the BLA withdrawal for those with extensive-stage SCLC. These reports collectively emphasize the regulatory hurdles facing the partnership's pipeline. The context of this event is rooted in a high-stakes $4 billion agreement between Merck and Daiichi Sankyo. The partnership aims to leverage ADC technology to expand cancer treatment options, but the current withdrawal of the ifinatamab deruxtecan filing indicates difficulties in meeting FDA requirements for this specific therapy.


This latest development follows a pattern of challenges for the duo, as Reuters notes this is not the first time they have pulled a partnered application in the US market. The financial stakes are high, given the valuation of the overarching deal and the potential for lung cancer therapeutics. Future attention will likely focus on whether the companies seek to modify their data or approach to re-file the application for ifinatamab deruxtecan. Investors are already analyzing the impact of the news, as seen in reporting from simplywall.st, which questions if Daiichi Sankyo Company (TSE:4568) has become undervalued following the FDA filing withdrawal. Observers will be monitoring for further communication from the FDA regarding the specific nature of the pushback and whether other therapies within the $4 billion partnership remain on track for approval.

## Multi-Source Evidence Table
| Source Outlet | Headline | Verification URL |
|---|---|---|
| simplywall.st | Is Daiichi Sankyo Company (TSE:4568) Undervalued On Its FDA Filing Withdrawal? | [Source Link](https://news.google.com/rss/articles/CBMi5wFBVV95cUxQRUo2YVZiX2V0UkxRcTUwZ1JfY21hV0x0cWkzOEVpU0Q0LUZpODBVR05GNk4xQ2E5QXM0ODFSRGs0VHBpRFdDTTA4NU9HTF9Cc3BjNzVxd3Z6dXJrcVFEYkpaU0c2Rlk5TEtzaGN6MTNuSkVIclJvSmhUU1ZxUmREVld0NHpNVTMyVnZ6ZGJKZkQ4ZHBaOTY3cVVfWkItYlhHVUZOWGVDbmdCQUFXUjY2R0pyWDVkRWJ1S25zb0x4bWU0LUxNc3dfYjllb3VzVnlXTXJnWjk3d2FsZWRZUnFNOFBEUTRzN2PSAewBQVVfeXFMTjJkUUtJWlZyVnhCWS1SazVpYXJiOE5sVUV5cDJ4RVBVZnFiakhlVGlTN1ZUSVZVaDNHMm13VlpGcG1sb3lPdmpxX1hmbU8wVXd3VHhydC00S0U2RGkyOE02NTF5TG1WZFlOX00) |
| Endpoints News | Merck, Daiichi scrap FDA application for B7-H3 ADC in lung cancer | [Source Link](https://news.google.com/rss/articles/CBMikgFBVV95cUxQRXhOX3F6Z0Q2LVk3TVkxeHBkVWN1dVp5YXRNalB6a0RSaEswMm9wUUxaM2lwd0I4VFdGb21UOW9rM2NSLU96eFFRVndUa2dsSGFSWDdER2picXhzLUtOMGlrM1YxSlN3bG5fSGFfa1BxZjZDZHJ1UHJtdmRab212NjBIYmNSNkwxOHRQUWJKNERrUQ?oc=5) |
| OncLive | Ifinatamab Deruxtecan BLA Voluntarily Withdrawn in Previously Treated Extensive-Stage SCLC | [Source Link](https://news.google.com/rss/articles/CBMiuwFBVV95cUxOVFhBNkVDc2JzdndSaUNzZTdyTXpNUXAwUkhGdVpxdXF3MFQtNm1rb0g3OFo2elFWUWZEUGRRY2tabTVNcUJTaDl1UFFTYzVHX2hWU3ZKSTBhTm1uT2lnMnQ4Tkl5NldEUUJ5a2thdndwcmZtQVd2bjJKcWVlcHdlZkZYRWxiQ3p3R054VFVMLXBIXzhDSmlTWWFvV2VVTXVfMGE5cHdiMWRYZjZFSnZHcHZObV9URWhQRURv?oc=5) |
| Reuters | Merck, Daiichi pull US application for second partnered cancer therapy | [Source Link](https://news.google.com/rss/articles/CBMitAFBVV95cUxPY255UmdNQXFqU296Vi13YzlWX3Rnei1KX1NNZGQybU1hUVJUeUxxUU9oa0dvWk0zTzZXRk5xS01kVGhXWG1Ca000VVlZUlpJdVA1c1N2WEJCU1BGM3huRjlCZHZkQzEzdUdQLTZZS1Zka0ZRNi1Ya1lmekQ4M1Vnd2xOWTRUSldYdzZDMnFlQzc3dXdlWWV0WHJiNUZSUjZ0RDhXWFJfY3Q4TjhxVU8zczZGVHc?oc=5) |
| Fierce Biotech | Merck, Daiichi pull lung cancer filing after FDA pushback deals another blow to $4B deal | [Source Link](https://news.google.com/rss/articles/CBMixwFBVV95cUxOa3RsYnRvVkpLUXJzSEpYMWNPWE0zckh1VUp2TjAxRzhFTlVUa0U0VXV3aTBGVUg3VTJEdVotNGxXNTYwZ1RwN3RKUmxlSjlTMFoxWVE1Zjh2a3dWNFFwMmVoZkxGRFd5MElWZ2ZBdERrelVVQVNLX1NQdm1NbnJXazBuclZMVEJFb3lzdkJDVVBLMTJLNm9UdVVVRmNaWFB4clRCeGk2NElZUUM0a2Nob3IyT0dqcVJ4NkdyS3J4Sk16bkRwUzZv?oc=5) |

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*Canonical Source: https://pulse.byoviral.com/trend/2026-09-28/merck-daiichi-pull-lung-cancer-filing-after-fda-pushback-deals-another-blow-to*