United States Patent 4,808,616: Scope, Claim-by-Claim Landscape, and Competitive Patent Positioning
US Patent 4,808,616 is a steroidal small-molecule composition and method patent centered on specific 6-methylenandrosta-1,4-diene-3,17-dione-type structures and selected C1/C4 substitution and 6-ethyliden variants. The claim set is built to (i) lock the core chemical class, (ii) cover specific substituted embodiments, and (iii) extend protection into formulations and use-driven indications in hormone-dependent cancers and prostatic hypertrophy/hyperplasia.
What is the technical scope of the chemistry in Claim 1?
Claim 1: single chemical species
- Claim 1 is directed to:
- 6-methylenandrosta-1,4-diene-3,17-dione
Practical meaning for scope
Claim 1 is a “base scaffold” lock. It is narrow in that it covers one defined structure, but it anchors the broader dependent structure coverage in Claim 2. The rest of the patent’s freedom-to-operate relevance typically comes from Claim 2 (substituted analogs) and from Claims 3 to 7 (formulation and use).
How broad is Claim 2 across substituted analogs?
Claim 2: defined group of enumerated compounds
Claim 2 covers a closed list of specific compounds. The claim is not an open genus; it is an “enumeration” claim that lists every supported variant.
The covered compounds are:
6-methylenandrosta-1,4-diene-3,17-dione variants
- 1-methyl-6-methylenandrosta-1,4-diene-3,17-dione
- 1-ethyl-6-methylenandrosta-1,4-diene-3,17-dione
- 4-methyl-6-methylenandrosta-1,4-diene-3,17-dione
- 4-ethyl-6-methylenandrosta-1,4-diene-3,17-dione
- 4-fluoro-6-methylenandrosta-1,4-diene-3,17-dione
- 4-chloro-6-methylenandrosta-1,4-diene-3,17-dione
6-ethylidenandrosta-1,4-diene-3,17-dione variants
- 6-ethylidenandrosta-1,4-diene-3,17-dione
- 6-propylidenandrosta-1,4-diene-3,17-dione
1-methyl or 4-fluoro/chloro combined with 6-methylen
- 4-fluoro-1-methyl-6-methylenandrosta-1,4-diene-3,17-dione
- 4-chloro-1-methyl-6-methylenandrosta-1,4-diene-3,17-dione
1-methyl combined with 6-ethyliden, and 4-fluoro combined with 6-ethyliden
- 1-methyl-6-ethylidenandrosta-1,4-diene-3,17-dione
- 4-fluoro-6-ethylidenandrosta-1,4-diene-3,17-dione
Scope implications for landscape and design-around
- Closed list: Unlisted steroid analogs are outside Claim 2 by claim text, even if they appear structurally related.
- Core “6-methylene/6-ethylidene/6-propylidene” lock: Claim 2 is strongly constrained to a specific ring unsaturation pattern at C6 (methylen vs ethyliden vs propyliden) plus fixed positions for substitutions (C1, C4).
- Halogen constrained: Fluoro and chloro appear only on the 4-position, and only in the specific enumerated combinations.
- Substitution constrained: The C1 substitutions in the claim set are limited to methyl and ethyl, and the C4 substitutions are limited to methyl, ethyl, fluoro, chloro, plus those explicitly paired with 1-methyl.
This claim architecture typically creates two practical zones for competitors:
- Direct overlap risk: If a competitor’s lead is one of the enumerated structures, Claim 1 or 2 is triggered.
- Design-around opportunity: If the competitor’s chemistry changes the enumerated substitution pattern or the C6 unsaturation type, Claim 2 may not read (but later use claims could still be an issue if formulations are argued as equivalents or if other patents cover the variants).
What claims extend protection into formulations and indications?
Claim 3: composition (general)
Claim 3:
- A pharmaceutical composition with a suitable carrier and/or diluent containing a therapeutically effective amount of a compound of Claim 1 or 2 (or a pharmaceutically acceptable salt).
Scope
This is a standard composition claim that typically covers:
- the active ingredient(s) from Claim 1 or 2,
- any formulation vehicles compatible with the active,
- and salt forms.
Claim 4: composition for hormone-dependent cancers (advanced)
Claim 4:
- A composition suitable for treatment of:
- advanced hormone-dependent breast, pancreatic, endometrial and ovarian cancers
- active: therapeutically effective amount of a compound of Claim 1 or 2.
Scope
- This is an indication-specific composition claim. Even if an entity can avoid Claim 3 by arguing a formulation does not qualify, Claim 4 can still block if the formulation is explicitly for these advanced hormone-dependent cancers.
Claim 5: composition for prostatic hypertrophy/hyperplasia
Claim 5:
- Composition suitable for treatment of:
- prostatic hypertrophy and prostatic hyperplasia
- active: therapeutically effective amount of Claim 1 or 2.
Claim 6: method of treatment for advanced hormone-dependent cancers
Claim 6:
- Method comprising administering an effective amount of Claim 1 or 2 to patients with:
- advanced hormone-dependent breast, pancreatic, endometrial or ovarian cancer.
Claim 7: method of treatment for prostatic hypertrophy/hyperplasia
Claim 7:
- Method comprising administering effective amounts of Claim 1 or 2 for:
- prostatic hypertrophy or prostatic hyperplasia.
Landscape meaning of Claims 3 to 7
This patent does not rely solely on chemical claims. It uses:
- composition claims (Claims 3, 4, 5),
- use claims (Claims 6, 7).
In practice, that makes the patent relevant even when a competitor modifies formulation chemistry. The key risk is whether the competitor is still using one of the claimed actives and targeting the claimed indication.
How is the indication scope framed, and where does it create boundary risk?
Indications covered
- Advanced hormone-dependent cancers:
- breast
- pancreatic
- endometrial
- ovarian
- Prostate conditions:
- prostatic hypertrophy
- prostatic hyperplasia
Boundary characteristics
- “Advanced” is written into the cancer claim set (Claims 4 and 6). That can create a factual boundary for enforcement and for label/labeling strategy.
- “Hormone-dependent” is also written, which can require the cancer phenotype to be treated under that framing.
- The claims are written as oncology and prostate-specific, not broad endocrine disease coverage.
From an IP strategy standpoint, this patent tends to be most threatening for programs that:
- use one of the enumerated steroids, and
- position clinical development or commercialization specifically within these indications.
What does the claim structure imply about enforceable patent reach?
Claim hierarchy
- Claim 1: one defined compound.
- Claim 2: enumerated alternatives within the steroid scaffold class.
- Claims 3 to 5: compositions.
- Claims 6 to 7: methods.
Enforceability leverage
- If a competitor’s active is exactly Claim 1 or any Claim 2 compound, the patent can be asserted across:
- direct product compositions (Claims 3 to 5),
- medical treatment activity (Claims 6 to 7).
- If a competitor uses an active outside the enumerated list, direct coverage for Claims 1 and 2 is less likely. The remaining risk then becomes whether other patents in the same family cover that chemistry or whether the competitor’s product is still argued to fall within the enumerated structures via chemical interpretation.
Patent landscape positioning: what matters beyond this single patent?
Because you provided the claim texts but not bibliographic or family identifiers (application/priority data, expiration, and cited references), a complete cross-document landscape map cannot be produced from the record provided.
However, the claim architecture itself defines how this patent typically sits relative to other rights in the same area:
Likely neighboring protection categories (based on claim design)
- Core chemistry claims in the same family:
- Enumerated variants like those in Claim 2.
- Formulation and salt claims:
- Claim 3 style broad composition coverage, plus dependent formulations (not provided).
- Indication claims:
- Claim 4/6 and Claim 5/7 style use coverage.
- Related steroid scaffold patents:
- Other substitutions on the same backbone often appear in distinct patents that target adjacent structure space.
Competitive impact for R&D decisions
- Programs that remain tightly inside the enumerated actives will face high patent friction in the claimed indications.
- Programs that shift away from the enumerated actives can reduce direct read, but may still face second-order friction if:
- other patents in the same technology set cover the broader scaffold,
- or the competitor’s use and patient population align with the use-driven claims of other rights.
Claim-by-claim scope table
| Claim |
Claim type |
What is covered |
Effective scope trigger |
| 1 |
Chemical |
6-methylenandrosta-1,4-diene-3,17-dione |
Active ingredient matches Claim 1 exactly |
| 2 |
Chemical (enumerated) |
12 specific substituted methylen/ethyliden/propyliden analogs |
Active ingredient matches one listed structure |
| 3 |
Composition |
Composition with carrier/diluent + active from Claim 1 or 2 (or salts) |
Marketed/used product contains Claim 1/2 active in a therapeutically effective amount |
| 4 |
Indication composition |
Advanced hormone-dependent breast/pancreatic/endometrial/ovarian cancers |
Product is formulated and used for those indications |
| 5 |
Indication composition |
Prostatic hypertrophy/hyperplasia |
Product is formulated and used for those indications |
| 6 |
Method of treatment |
Administer Claim 1/2 to treat advanced hormone-dependent breast/pancreatic/endometrial/ovarian cancer |
Medical treatment activity in that indicated patient population |
| 7 |
Method of treatment |
Administer Claim 1/2 to treat prostatic hypertrophy/hyperplasia |
Medical treatment activity in those conditions |
Key Takeaways
- The patent’s chemical scope is anchored by Claim 1 (one defined compound) and expanded by Claim 2, which is a closed enumeration of 12 specific substituted analogs centered on 6-methylene/6-ethyliden/6-propyliden steroidal 1,4-diene-3,17-dione structures.
- Protection extends beyond the molecule into formulations (Claims 3 to 5) and use-driven indication claims (Claims 6 and 7) covering:
- advanced hormone-dependent breast, pancreatic, endometrial and ovarian cancers
- prostatic hypertrophy and prostatic hyperplasia
- A competitive program’s IP risk is highest when it uses one of the enumerated actives from Claim 1 or Claim 2 and targets the claimed indications, where even formulation changes may not avoid coverage.
FAQs
1. Does the patent cover a broad genus of steroid analogs?
No. Claim 2 is a closed list of enumerated compounds; it does not read as a general genus claim over all substitutions on the scaffold.
2. What is the main actionable claim set for infringement risk?
Claims 3 to 7, because they attach protection to marketed formulations and medical treatment activity in the specified indications, provided the active ingredient matches Claim 1 or Claim 2.
3. What parts of the claim language create factual boundary conditions in cancer indications?
“Advanced” and “hormone-dependent” are both written into Claims 4 and 6, shaping enforceability around patient population and treatment context.
4. Can a competitor avoid the patent by changing formulation excipients?
If the competitor still uses a Claim 1 or Claim 2 active, excipient changes alone typically do not avoid composition claims (Claims 3 to 5) that allow “suitable carriers and/or diluents.”
5. Which chemical modifications are explicitly protected under Claim 2?
Explicitly protected variants include C1 methyl/ethyl substitutions, C4 methyl/ethyl/fluoro/chloro substitutions, and specific C6 unsaturation patterns (methylen vs ethyliden vs propyliden), but only as enumerated in the claim.
References
[1] United States Patent 4,808,616 (claim text as provided by user).
