Why do pharmaceutical patents needs to list other drugs the patented drug could be combined with?

Question

I know this is quite a specialist subject but I thought there might be some pharma patent experts here.

I am trying to understand why when you apply for a patent for a particular therapeutic compound, patent applications tend to explicitly list many compounds (often produced by other companies) that the compound the subject matter of the application may be be combined with in the future.

For example, here is a patent application for anti-HIV antibodies:

https://patents.google.com/patent/JP2020120689A/en?oq=JP2020120689A

In it they write:

The antibody or fragment thereof disclosed herein can be combined with one or more additional therapeutic agents in any dosage of the antibody or fragment thereof (eg, 50 mg to 1000 mg of compound). Also, the antibody or fragment thereof disclosed herein may be used at any dosage of the antibody or fragment thereof (eg, about 0.1 mg to about 50 mg, or 50 mg to 4000 mg of compound per kg body weight of the subject), It may be combined with one or more additional therapeutic agents.

In one embodiment, one or more of the antibodies or fragments thereof or pharmaceutically acceptable salts thereof disclosed herein (eg, 1, 2, 3, 1, 2 or 3, Or one to three) additional therapeutic agents and pharmaceutical compositions containing them in combination with a pharmaceutically acceptable carrier, diluent or additive are provided.

In one embodiment, one or more (eg, one, two, three, one or two) of the antibodies or fragments thereof or pharmaceutically acceptable salts thereof disclosed herein, Or one to three) additional therapeutic agents are provided

They then go on to list almost every known HIV therapeutic that exists.

Question:

1. Why do they need to list all the potential drugs that the compound (the subject of the patent application) may possibly be combined with to form a treatment? What would the risk be if they didn't do this?

Answer 1

Why exhaustively list combinations for a drug?

It could be to prevent others from patenting these combinations, or to establish that they thought of these combinations first.

Background:

To be patentable, an invention must be novel, useful, and not obvious (sorry for yelling). By literally writing out the drugs that the compound can be used for, the inventors can prevent others from being able to argue that the combinations are novel or not obvious. Perhaps they have other patent filings in the works that claim these combinations, or maybe they just want to ensure that they have freedom to operate.

Answer 2

The description in the body of the application (often called the specification) should enable the claims. I looked at the corresponding claims in the US application as the Japanese claim is just "1. The invention described herein.". I'm not very experienced with Japanese patents so I can comment on the claim, but in a US or European patent the claims need to be enabled by the rest of the patent. If you want to claim a combination of drugs then the specification needs to explain that. There are a lot of claims even after the first 29 were canceled. If you study them, then the construction of the rest of the application may be clearer.