Obviousness

Based on an analysis of U.S. Patent 10,980,934 ('934 patent) and the state of the art prior to its priority date of May 30, 2017, several of its claims appear vulnerable to an obviousness challenge under 35 U.S.C. § 103. An obviousness rejection requires that the claimed invention would have been obvious to a person having ordinary skill in the art (PHOSITA) at the time the invention was made.

A PHOSITA in this field would be a biomedical engineer or medical professional with several years of experience in the design and operation of apheresis systems and a thorough understanding of hematology and fluid dynamics as they relate to blood donation.

Core Inventive Concepts of the '934 Patent

The central theme of the '934 patent is a move away from generic, weight-based plasma collection limits to a highly individualized and precise methodology. The key steps, as distilled from independent claims 1, 9, and 17, are:

1. Donor-Specific Volume Calculation: Determining a donor's total plasma volume using their specific height, weight, and hematocrit.
2. Personalized Target Volume: Calculating a target plasma collection volume as a specific percentage (e.g., 28.5%) of the donor's calculated total plasma volume.
3. Pure Plasma Measurement: Calculating the volume of pure plasma being collected by actively accounting for and subtracting the volume of the added anticoagulant from the total collected fluid.
4. Targeted Collection Stop: Terminating the collection procedure precisely when the calculated pure plasma volume equals the personalized target volume.
5. Targeted Fluid Replacement: Managing the donor's post-procedure fluid balance by returning other blood components and a specific volume of saline to achieve a predetermined target intravascular deficit.

Obviousness Combination of Prior Art

The claims of the '934 patent would have been obvious based on a combination of prior art that taught: (A) methods for calculating a patient's total blood and plasma volume; (B) standard apheresis systems that monitor fluid volumes using pumps and scales; and (C) the established medical practice of administering saline to manage donor fluid balance.

Reference A: Calculating Patient-Specific Plasma Volume

The concept of calculating a person's total blood volume (and by extension, plasma volume, given a hematocrit value) based on physiological parameters like height and weight was well-established in the medical field long before 2017.

• The '934 patent itself, in the Detailed Description (Col. 9, lines 46-63), points to a known method for calculating total blood volume using the donor's Body Mass Index (BMI). It explicitly references the scientific paper "Lemmens et al., Estimating Blood Volume in Obese and Morbidly Obese Patients, Obesity Surgery, 2006:16, 773-776." This demonstrates that the formula and the scientific basis for calculating a donor-specific blood volume were part of the public domain and known to the art.

A PHOSITA would have recognized that using such established formulas would provide a more accurate, individualized basis for determining safe donation limits than the broad weight categories described as the prior art standard in the '934 patent's "Background Art" section.

Reference B: Standard Apheresis System Capabilities

Prior art apheresis systems, as a matter of routine operation, already contained the necessary hardware and control logic to measure and control fluid volumes.

• Anticoagulant Monitoring: These systems utilize precise pumps to introduce anticoagulant into the whole blood being drawn. As the '934 patent discloses, the volume of anticoagulant can be determined by "a number of rotations of an anticoagulant pump" (Claim 2) or by weight using a scale for the anticoagulant source (Claim 12). These are standard, inherent capabilities of such systems. A PHOSITA would understand that the data from these components (pump rotations or weight change) could be used by the system's controller to calculate the total volume of anticoagulant dispensed.
• Collected Product Measurement: Similarly, prior art systems used weight sensors to measure the total volume of the collected product (plasma plus anticoagulant), as acknowledged in the '934 patent (Col. 7, lines 1-4).

The step of subtracting the known volume of dispensed anticoagulant from the known total volume of collected fluid to find the volume of "pure plasma" is not an inventive leap. It is a simple arithmetic calculation that a PHOSITA would find obvious to implement in a system's software to get a more accurate measurement of the actual therapeutic product being collected.

Reference C: Managing Intravascular Deficit with Saline

The practice of returning saline to a donor to compensate for the removed plasma volume is a fundamental safety feature in plasmapheresis. This is done to maintain the donor's fluid balance (isovolemia) and prevent adverse reactions like fainting or vasovagal reactions.

• The '934 patent describes this as part of its method, aiming for a "target intravascular deficit" (Claim 1). This is simply applying a more precise name and target value to an existing, well-understood safety procedure. A PHOSITA would be well aware of the need for saline compensation and would be motivated to control it precisely to enhance donor safety and comfort.

Motivation to Combine

A person of ordinary skill in the art would have been motivated to combine these known elements for several compelling reasons:

1. Enhancing Donor Safety: The primary motivation would be to improve donor safety. By calculating a donor's specific plasma volume (from Reference A), a precise, individualized collection limit can be set, preventing the over-collection of plasma from smaller donors or those with lower plasma volumes, a risk identified in the '934 patent's background section. Precisely managing the intravascular deficit with saline (Reference C) further contributes to this goal.
2. Maximizing Plasma Yield: For plasma collection centers, there is a strong economic motivation to collect the maximum allowable amount of plasma from each qualified donor. The FDA limits are based on pure plasma volume. Prior art systems, by collecting to a total mixed volume limit, would necessarily under-collect pure plasma, especially from donors with high hematocrit ('934 patent, Col. 7, lines 5-16). By using the hardware in a standard system (Reference B) to calculate and track the pure plasma volume, a PHOSITA would be motivated to combine these techniques to consistently and safely reach the true regulatory limit, thereby maximizing yield and efficiency.
3. Standardization and Predictability: Combining these elements would lead to a more standardized and predictable procedure where the percentage of plasma collected is consistent across donors, rather than varying widely as stated in the background of the '934 patent. This improves quality control and the overall management of the donation process.

In conclusion, the core claims of the '934 patent describe a system and method that combine elements already known and practiced in the art. The calculation of donor-specific plasma volume was known (Reference A), the hardware to measure components was present in apheresis systems (Reference B), and the use of saline for fluid balance was standard practice (Reference C). The motivation to combine these elements to create a safer, more efficient, and more precise plasma collection process would have been readily apparent to a person having ordinary skill in the art before May 2017. Therefore, the claims appear obvious under 35 U.S.C. § 103.