Scholar Rock · Nasdaq: SRRK · apitegromab (ISEMBYLD)

The 8-K names the facility the letter leaves unnamed and repeats that the observations are not specific to apitegromab. It does not mention the letter's possible re-inspection and pre-license inspection, or the pregnancy safety study the letter says will be required if approved.

The letter refers to a CGMP inspection of a facility it does not name. The 8-K headline: “Solely Related to Observations Identified at Catalent Indiana LLC Fill-Finish Facility” [8-K · Sep 23], with “No other approvability issues cited in CRL” [8-K · Sep 23]. The letter says the deficiencies “may not be specific to your application” [FDA · Sep 22 · p. 1]; the 8-K says “The observations are not specific to apitegromab” [8-K · Sep 23].

The letter asks for “the date(s) of the facility’s response(s) to the FDA Form 483” [FDA · Sep 22 · p. 1]; the 8-K says “Catalent Indiana submitted a comprehensive response in early August 2025” [8-K · Sep 23]. The letter says the responses “may require re-inspection of the facility” [FDA · Sep 22 · p. 1] and that “FDA may need to conduct a PLI of the facility” [FDA · Sep 22 · p. 1]; the 8-K says “Scholar Rock believes that the FDA will be able to act expeditiously on the application once the manufacturing issues have been resolved” [8-K · Sep 23]. The 8-K does not mention re-inspection or a pre-license inspection. [8-K · searched]

The 8-K says “The CRL did not cite any other approvability concerns, including apitegromab’s efficacy and safety data” [8-K · Sep 23]. The letter says that, if approved, “you will be required to conduct the following” [FDA · Sep 22 · p. 4]: a pregnancy safety study “for a minimum of 10 years” [FDA · Sep 22 · p. 4]. The 8-K does not mention that study. [8-K · searched]

After the letter, the company reported an 'official action indicated' classification and a warning letter at Catalent Indiana, added a second fill-finish facility, and resubmitted before reinspection. As of Aug 6, 2026 the classification was pending; the Sep 2026 approval filing does not mention either facility.

On Oct 10, 2025 the company was told that the FDA “has determined that the inspection classification of this facility is “official action indicated” [8-K · Oct 14]; on Dec 2 it reported that “Catalent Indiana received a warning letter from the FDA” [8-K · Dec 2]. In November it said Catalent “expects the facility to be ready for reinspection by the end of this year” [8-K · Nov 14] and that it had “accelerated timelines with an additional fill-finish facility” [8-K · Nov 14].

On Mar 3, 2026: “Scholar Rock plans to resubmit the apitegromab BLA following a successful reinspection of the site” [8-K · Mar 3]. On Mar 31: “The decision to resubmit the apitegromab BLA prior to FDA reinspection of Catalent Indiana was made in alignment with the FDA” [8-K · Mar 31], and the resubmission “also includes a second U.S.-based fill-finish facility” [8-K · Mar 31].

On May 7 the company reported the FDA “completed reinspection of Catalent Indiana” [8-K · May 7]. On Aug 6: “The FDA inspection classification of Catalent Indiana following an April 2026 general site inspection is pending” [8-K · Aug 6], with the two facilities described as “two independent paths to an FDA approval decision” [8-K · Aug 6].

On Sep 11, 2026 the company “announced that the FDA has approved ISEMBYLD (apitegromab-mstn)” [8-K · Sep 14]. The approval press release and 8-K do not mention Catalent Indiana, either fill-finish facility or an inspection. [8-K · searched]

The letter cites deficiencies from a CGMP inspection of a facility it does not name: the facility must respond, may need re-inspection, and FDA may need a pre-license inspection. The letter also says a 10-year pregnancy safety study will be required if the BLA is approved.

The letter says the FDA “cannot approve this application in its present form” [FDA · Sep 22 · p. 1]. Under Facility Inspections: “Following a CGMP inspection of , listed in this application, FDA conveyed deficiencies to the representative of the facility” [FDA · Sep 22 · p. 1]; the letter's text does not name the facility. [FDA · searched]

The facility's responses “may require re-inspection of the facility” [FDA · Sep 22 · p. 1], and “Following resolution of the CGMP inspection, FDA may need to conduct a PLI of the facility” [FDA · Sep 22 · p. 1]. The letter says “The deficiencies identified during the inspection may not be specific to your application” [FDA · Sep 22 · p. 1].

It also asks the company to “Submit draft labeling” [FDA · Sep 22 · p. 1] and “Submit draft carton and container labeling” [FDA · Sep 22 · p. 2], and says “A resubmission must fully address all the deficiencies listed in this letter” [FDA · Sep 22 · p. 6].

Separately, the FDA “has determined that, if BLA 761463 is approved, you will be required to conduct the following” [FDA · Sep 22 · p. 4]: a “worldwide single-arm pregnancy safety study to collect and analyze information for a minimum of 10 years” [FDA · Sep 22 · p. 4]. The letter lists “comments/recommendations that are not approvability issues: Product Quality” [FDA · Sep 22 · p. 5]; in the published letter the heading is followed directly by the next section: “Product Quality OTHER” [FDA · Sep 22 · p. 5].

The pregnancy safety study set out in the 2025 letter is now a post-marketing requirement, and the company's Sep 15, 2026 8-K says management 'stated in error' on its investor call that no such commitments were required. Catalent Indiana's classification and the EMA review were pending as of Aug 6, 2026.

The 2025 letter says that, if approved, “you will be required to conduct the following” [FDA · Sep 22 · p. 4]: a “worldwide single-arm pregnancy safety study” [FDA · Sep 22 · p. 4]. The 8-K about the letter, and Scholar Rock's 10-Qs and 10-K up to Aug 2026, do not mention a pregnancy study. [8-K · searched]

After approval, the Sep 15, 2026 8-K says that on the investor call “the Company’s management stated in error that the FDA did not require any post-marketing safety commitments regarding bone or reproductive safety of ISEMBYLD” [8-K · Sep 15], and that “the FDA outlined a post-marketing requirement that the Company establish a pregnancy safety study” [8-K · Sep 15] and asked for “all serious and non-serious domestic and/or foreign cases of fractures as 15-day “alert reports” [8-K · Sep 15].

The approval covers adults and children 2 years and older “who are currently receiving a survival motor neuron 2 (SMN2)-targeted treatment” [8-K · Sep 14]. As of Aug 6, 2026, “The FDA inspection classification of Catalent Indiana following an April 2026 general site inspection is pending” [8-K · Aug 6], and the EMA “is awaiting the FDA inspection classification of Catalent Indiana” [8-K · Aug 6].

Not in this record: the FDA approval letter and label, the FDA's Form 483 and warning letter to Catalent Indiana, EMA documents, and Scholar Rock's filings after Sep 15, 2026. [not in record]