Details for Patent: 5,100,899

US Patent 5,100,899: Scope, Claim-by-Claim Analysis, and US Landscape for Rapamycin in Transplant Rejection Inhibition

US Patent 5,100,899 claims a treatment method that uses rapamycin to inhibit organ or tissue transplant rejection in mammals, with explicit dosage, route, and treatment-duration parameters in dependent claims. The independent claim is broad on target (any organ or tissue transplant rejection), patient (mammal “in need thereof”), and mechanism framing (rejection inhibition), while still limiting the active ingredient to rapamycin. The dependent claims narrow the dosage window, treatment length, and administration route.

What does US 5,100,899 claim in plain scope terms?

Independent claim scope (Claim 1)

Claim 1: “A method of inhibiting organ or tissue transplant rejection in a mammal in need thereof, comprising administering to said mammal a transplant rejection inhibiting amount of rapamycin.”

Key scope elements:

• Method of use only (no composition claim and no device claim).
• Indication: inhibiting “organ or tissue transplant rejection.”
• Population: “a mammal in need thereof.”
• Intervention: administering rapamycin.
• Limitation: “transplant rejection inhibiting amount” (functional dose language).

This is a classic “use claim” that can be used to reach many clinical regimens so long as the regimen includes rapamycin administration at an amount that is intended to inhibit rejection.

Dependent claim scope narrowing

• Claim 2: dosage range 0.5 to 50 mg/kg/day
• Claim 3: narrower dosage range 1 to 5 mg/kg/day
• Claim 4: treatment duration 1 to 180 days
• Claim 5: oral administration
• Claim 6: parenteral administration
• Claim 7: indefinite period of time to maintain inhibition

Claims 2 and 3 define numerical dose boundaries. Claims 4 and 7 define time-of-therapy boundaries (finite window vs indefinite maintenance). Claims 5 and 6 cover route of administration through “administered orally” and “administered parenterally,” which captures essentially all standard routes used in transplant settings, assuming rapamycin is delivered systemically by either oral or non-oral dosing.

How broad are the individual claim limitations from an infringement and freedom-to-operate lens?

1. Functional dose language vs hard ranges

• Claim 1 uses “transplant rejection inhibiting amount,” which typically gives the patentee room to argue infringement even if a regimen does not fall inside the explicit numeric ranges of dependent claims, provided efficacy evidence ties the dose to rejection inhibition.
• Claims 2 and 3 create “safe zones” and “risk zones”:
  • 0.5 to 50 mg/kg/day is explicitly claimed.
  • 1 to 5 mg/kg/day is a narrower subset.

From a landscape standpoint, the presence of both ranges matters. Even if a challenger designs around one range, the patentee can argue under Claim 1’s functional limitation unless the redesigned regimen clearly fails to be a rejection-inhibiting dose.

2. Duration: finite induction/therapy window vs indefinite maintenance

• Claim 4: 1 to 180 days.
• Claim 7: “indefinite period of time to maintain inhibition.”

These two claims overlap in practice only if “indefinite” is construed to include all time periods after some point. If an accused regimen is strictly limited to, for example, 30 days, Claim 4 is directly implicated; Claim 7 may be argued only if the regimen includes maintenance beyond a short course.

3. Route coverage is explicit

• Claim 5: oral.
• Claim 6: parenteral.

This makes route design-around harder because most transplant rapamycin use is already either oral or parenteral. Unless a regimen uses a substantially different administration mode outside these terms (rare for rapamycin’s established delivery), these dependents create layered infringement exposure.

What is the operational “claim map” across dosage, route, and time?

Claim coverage matrix

Takeaway from the claim stack

The independent claim anchors infringement to rapamycin + rejection inhibition in mammals. Dependent claims then stack specific numeric dose windows and therapy schedules. An accused regimen that matches multiple dependent limitations is exposed to multiple claim theories at once.

What is the likely US patent landscape around 5,100,899?

The practical US transplant rapamycin landscape is shaped by two interacting patent families:

1. Early rapamycin method-of-use and transplant rejection inhibition filings, such as US 5,100,899 itself, that claim use of rapamycin in transplant rejection contexts.
2. Subsequent rapamycin-analogue and related immunosuppression patent families, plus later formulations and dosing regimens, that can overlap in commercial regimens even when not literally identical to the 5,100,899 claim set.

How 5,100,899 typically positions relative to later rapamycin derivatives

Even without relying on any specific later patent document text here, the usual landscape pattern is:

• If later patents claim “rapamycin” itself, they can narrow or specify dosing, regimen, combination therapy, or patient populations, and they may sit as “blocking” or “design-around resistant” layers depending on claim construction.
• If later patents claim “rapamycin analogs” (rapalogs) (e.g., everolimus/temsirolimus) for transplant rejection, they are often outside the strict literal term “rapamycin” in US 5,100,899. In those cases, 5,100,899 may still be relevant if the later use claims hinge on the same active species or if “rapamycin” is interpreted broadly (which is fact- and claim-construction dependent).

Implication for FTO

• If a program is built around rapamycin (not a rapalog), US 5,100,899 is a direct method-of-use anchor for transplant rejection inhibition.
• If a program uses rapamycin analogs, the direct literal hit is less likely based solely on the claim language, but overlapping indications, combination regimens, and similar dosing windows often pull in other nearby patents.

What are the key design-around and risk-reduction levers against these claims?

Because the independent claim is broad, design-around is mostly about avoiding one of the three pillars: rapamycin, transplant rejection inhibition, or administration at a “rejection-inhibiting amount**.

1. Avoiding “rapamycin” as the active

• Using a rapamycin analog can avoid literal coverage if the claim term “rapamycin” is construed narrowly.
• Using combination immunosuppression where rapamycin is absent avoids Claim 1 entirely.

2. Avoiding the “rejection inhibiting amount”

For Claim 1, dosing can be the main lever:

• Dependent claims provide explicit ranges (0.5 to 50 mg/kg/day and 1 to 5 mg/kg/day).
• If an accused regimen is demonstrably outside those ranges, the independent claim still requires that the administered dose is a rejection-inhibiting amount. A regimen that does not inhibit rejection would not meet the functional limitation, though this depends on evidence and claim interpretation.

3. Route

• Claims 5 and 6 cover oral and parenteral.
• If a regimen used a route not captured by “orally” or “parenterally,” route design-around could be relevant. In practice, most systemic delivery approaches in transplant settings are oral or parenteral.

4. Duration

• Short courses in the 1 to 180 day window are directly implicated by Claim 4 if rapamycin dosing supports rejection inhibition.
• Long-term maintenance is implicated by Claim 7 if the regimen is truly “indefinite” maintenance.

What does the claim structure imply for enforcement posture?

US 5,100,899’s claim structure supports:

• Broad assertion via Claim 1 against any rapamycin-based transplant rejection inhibition regimen in mammals, especially if the dose is plausibly within clinically effective territory.
• Layered narrowing via dependents to support multiple claim theories for specific dosing schedules, especially if a regimen falls into 0.5 to 50 mg/kg/day or 1 to 5 mg/kg/day, and if the therapy duration is within 1 to 180 days or indefinite maintenance.

Are there overlaps or stacking with standard transplant immunosuppression regimens?

Most transplant immunosuppression regimens are combination therapies. US 5,100,899 is not limited to monotherapy in the claim text provided; it only requires that rapamycin be administered in a rejection-inhibiting amount.

So if a combination regimen includes rapamycin, the method can still fall within Claim 1 and potentially within the dependent claims if the dose, route, and duration align.

What is the practical patent landscape summary for investors and R&D teams?

Core conclusion

US 5,100,899 is a foundational rapamycin transplant rejection inhibition method-of-use patent with:

• A broad independent claim tied to rapamycin administration for rejection inhibition in mammals.
• Numeric and operational dependent claims covering dose, route, and time on therapy.

Risk profile by program type

• Rapamycin-based transplant indication program: highest direct risk because Claim 1 maps directly to method-of-use administration.
• Rapalog-based program: lower direct literal risk against this specific patent term set, but the transplant space generally has dense adjacent IP, often including method-of-use and combination regimen claims.
• Formulation-only program using rapamycin: still likely high risk if the method-of-use practice includes rejection inhibition and falls within Claim 1’s functional and the dependent claim parameters.

Key Takeaways

• US 5,100,899 claims a method of inhibiting organ/tissue transplant rejection in mammals by administering rapamycin.
• Claim 1 is broad: functional dosing, no duration or route limits, and no restriction to specific organs or tissues.
• Claims 2 and 3 add enforceable numeric windows: 0.5 to 50 mg/kg/day and 1 to 5 mg/kg/day.
• Claims 4 and 7 cover 1 to 180 days and indefinite maintenance.
• Claims 5 and 6 cover oral and parenteral administration.
• In the US landscape, rapamycin-based transplant regimens typically face direct method-of-use claim exposure from patents like 5,100,899, while rapalog programs tend to face different, often adjacent, patent families.

FAQs

1. What is the single biggest scope driver in US 5,100,899?

Claim 1’s functional limitation: administering a “transplant rejection inhibiting amount of rapamycin” to a mammal with transplant rejection needs. That language supports enforcement beyond the specific numeric ranges in dependent claims.

2. Do Claims 2 and 3 limit the independent claim?

They narrow specific dependent claim coverage windows, but they do not eliminate Claim 1’s broader “inhibiting amount” framework. A regimen outside the numeric ranges can still be argued to satisfy Claim 1 if it is shown to inhibit rejection.

3. Does the patent cover only monotherapy with rapamycin?

The claim language provided does not restrict to monotherapy. If rapamycin is administered in a rejection-inhibiting amount, the method can fall within Claim 1 even if other agents are also used.

4. How does route affect infringement risk?

Oral and parenteral are explicitly covered in dependent claims (Claims 5 and 6). Most systemic rapamycin regimens used clinically are likely to fit within these terms.

5. Is short-course therapy safe if it is only within days?

A therapy within 1 to 180 days aligns with Claim 4 if the dose is a rejection-inhibiting amount. Duration alone is not a reliable design-around unless it clearly avoids the claimed windows and the rejection-inhibiting requirement.

References

[1] US Patent 5,100,899. “Method of inhibiting organ or tissue transplant rejection in a mammal.” (Claims as provided in prompt).