Dinutuximab ATC hierarchy stops at ATC 5th level in concept_ancestor table

Vocabulary Users
1

There are two standard RxNorm Ingredients for dinutuximab:

concept_id concept_name vocabulary_id concept_class_id standard_concept
46221699 dinutuximab RxNorm Ingredient S
40685018 Dinutuximab beta RxNorm Extension Ingredient S

When I look at all ATC ancestors of dinutuximab, it only shows an invalid ATC 5th level:

SELECT C.* FROM CONCEPT_ANCESTOR CA
LEFT JOIN CONCEPT C ON CA.ancestor_concept_id = C.concept_id
WHERE descendant_concept_id = 46221699
AND vocabulary_id = 'ATC'
concept_id concept_name domain_id vocabulary_id concept_class_id standard_concept concept_code valid_start_date valid_end_date invalid_reason
45893514 [U] dinutuximab beta; parenteral Drug ATC ATC 5th NULL L01XC16 1970-01-01 2022-01-01 U

When I look at ATC ancestors for Dinutuximab beta it shows the entire hierarchy up to ATC 1 including the invalid and a valid ATC 5th level:

SELECT C.* FROM CONCEPT_ANCESTOR CA
LEFT JOIN CONCEPT C ON CA.ancestor_concept_id = C.concept_id
WHERE descendant_concept_id = 40685018
AND vocabulary_id = 'ATC'
concept_id concept_name domain_id vocabulary_id concept_class_id standard_concept concept_code valid_start_date valid_end_date invalid_reason
954957 dinutuximab beta; parenteral Drug ATC ATC 5th C L01FX06 2022-01-01 2099-12-31 NULL
955076 MONOCLONAL ANTIBODIES AND ANTIBODY DRUG CONJUGATES Drug ATC ATC 3rd C L01F 1970-01-01 2099-12-31 NULL
955113 Other monoclonal antibodies and antibody drug conjugates Drug ATC ATC 4th C L01FX 1970-01-01 2099-12-31 NULL
21601386 ANTINEOPLASTIC AND IMMUNOMODULATING AGENTS Drug ATC ATC 1st C L 1970-01-01 2099-12-31 NULL
21601387 ANTINEOPLASTIC AGENTS Drug ATC ATC 2nd C L01 1970-01-01 2099-12-31 NULL
45893514 [U] dinutuximab beta; parenteral Drug ATC ATC 5th NULL L01XC16 1970-01-01 2022-01-01 U

Is there another join I have to do get the entire hierarchy for the first dinutuximab? We currently map all our dinutuximab drugs to this ingredient (concept_id 46221699) and I was finding that when I search for all descendants of all Antineoplastic Agents (concept_id 21601387), this one was not showing up.