Patents - Tehrani v Hamilton Bonaduz AG and others

 

Jane Lambert

Intellectual Property Enterprise Court (HH Judge Hacon) Tehrani v Hamilton Bonaduz AG and others  [2021] EWHC 3457 (IPEC) (22 Dec 2021)

This was an action for patent infringement and a counterclaim for revocation.  The patent in suit was GB2423721B and not GB2424721 as stated in the transcript. The invention for which the patent was granted was a “Method and apparatus for controlling a ventilator”. The patentee, Professor Tehrani, complained that the marketing of Hamilton Medical's Invellivent-ASV system infringed her patent. The suppliers of that system, Hamilton Bondauz AG and others, challenged the validity of the patent on grounds of anticipation, obviousness and insufficiency.  The action and counterclaim came on for trial before Judge Hacon on 6 and 7 July 2021. By para [117] of his judgment in Tehrani v Hamilton Bonaduz AG and others [2021] EWHC 3457 which was delivered on 22 Dec 2021, the judge held that the patent was invalid for want of novelty and an inventive step but had it been valid claim 1 but not claim 45 would have been infringed.

The Invention

The abstract is as follows:

"Method and apparatus for controlling a ventilator are described. The invention can be used to control mechanical ventilators (56) as well as respiratory assist devices such as CPAP machines. The apparatus receives input data indicative of patient's oxygen level. A controller (10) determines PEEP, or CPAP, and FIO2, on the basis of data indicative of the patient's oxygen level. In an alternative embodiment, the apparatus further receives input data indicative of patient's carbon dioxide levels, respiratory elastance and airway resistance, and barometric pressure. The controller further utilizes the said input data to determine the optimal values of tidal volume and breathing frequency for a next breath of the patient, and uses the respiratory elastance and airway resistance data to determine any necessary adjustments in the I:E ratio. The controller also applies safety rules, detects and corrects artifacts, and generates warning signals when needed."

The judge set out the technical background to the invention between para [12] and para [27] of his judgment.   He summarized the teaching between [39] and [47].

Disputed Claims

Two claims were in dispute, namely claim 1 and claim 45.   His Honour broke them down into integers at paras [48] and [49]:

“1A An apparatus for automatically controlling a ventilator comprising:
1B first means for processing data indicative of at least a measured oxygen level of a patient, and for providing output data indicative of:
1C required concentration of oxygen in inspiratory gas of the patient (FiO2) and positive end-expiratory pressure (PEEP) for a next breath of the patient;
1D wherein FiO2 is determined to reduce the difference between the measured oxygen level of the patient and a desired value;
1E wherein PEEP is determined to keep a ratio of PEEP/FiO2 within a prescribed range and, while keeping the ratio within the prescribed range, to keep the measured oxygen level of the patient above a predefined value; and
1F second means, operatively coupled to the first means, for providing control signals, based on the output data provided by the first means, to the ventilator;
1G wherein the control signals provided to the ventilator automatically control PEEP, and FiO2, for a next breath of the patient.”

At para [49], Judge Hacon said:

"In broad summary, claim 45 adds to claim 1 the requirement that the apparatus controlling the ventilator controls not only the PEEP and FiO2, i.e. oxygenation, but also ventilation including breathing frequency and I:E ratio:

'45A An apparatus for automatically controlling a ventilator comprising:
45B (a) means for providing data indicative of the measured oxygen level of the patient;
45C (b) means for providing data indicative of the measured carbon dioxide level of the patient;
45D (c) means for providing data indicative of respiratory elastance, and respiratory airway resistance of the patient;
45E (d) a programmable controller storing executable instructions that when executed perform the steps of:
45F (I) determining, from the data indicative of the measured oxygen level of the patient provided by (a), a required concentration of oxygen in an inspiratory gas of the patient, FiO2, to reduce a difference between the measured oxygen level of the patient and a desired value, and providing a data signal indicative of the required FiO2;
45G (II) determining a required positive end-expiratory pressure, PEEP, and providing a data signal indicative of the required PEEP, wherein the required PEEP maintains a ratio of PEEP/ FiO2 within a prescribed range, and while the ratio is maintained within the prescribed range, to keep the measured oxygen level of the patient above a predefined value;
45H (III) determining, based upon the data provided by (a), (b), and (c), an optimal breathing frequency, a required ventilation, and a required adjustment in inspiration to expiration time ratio, I:E, for a next breath of the patient, and providing data signals indicative of the same; and,
45I (e) means for providing to the ventilator, based upon the data signals provided by (I), (II) and (III), final data signals for automatically controlling: (i) the required FiO2, the required PEEP, (iii) the optimal breathing frequency, (iv) the required ventilation, (v) the required adjustment in I:E ratio, for a next breath of the patient.'”

Skilled Addressee

At para [30] Judge Hacon said that the skilled addressee was a team consisting of an engineer accompanied by a respiratory or critical care physician.  He set out their common general knowledge between [31] and [38].

Infringement

The parties agreed that Actavis Group PTC EHF and others v ICOS Corporation and another (2019) 167 BMLR 1, [2019] RPC 9, [2020] 1 All ER 213, [2019] UKSC 15, [2019] Bus LR 1318 applied.  The judge construed the disputed integers of claim 1 between [50] and [62].  The defendants supplied a product process description of the Intellivent-ASV system. There had been a dispute as to whether the product fell within integers IC, 1G and IE.  Integers IC and IG fell away with the judge's construction of the claim. Between paras [66] and [74]. He concluded that claim 1 is infringed on a normal construction of the claim when Intellivent-ASV is being used to increase treatment.  He next considered claim 45 and found that it was not infringed on a normal construction.  There was no argument on equivalents.

Invalidity

Hamilton argued that the patents lacked novelty and were obvious over the following prior art:

(1) Anderson J.R. and East T.D, A closed-loop controller for mechanical ventilation of patients with ARDS, Biomedical Sciences Instrumentation 2002, vol. 38m 289-294 (“Anderson”);
(2) Waisel et al., PEFIOS: An Expert Closed-Loop Oxygenation Algorithm, Medinfo ’95: Proceedings of the Eighth World Congress on Medical Informatics, Vancouver Trade & Convention Centre, Vancouver, British Columbia, 23-27 July 1995 (“Waisel”);
(3) US Patent No. 4 986 268 (“US 268”); and
(4) Tehrani F, Dual Control System for Ventilatory Treatment of Premature Infants, Proceedings of the 5th International Conference on Information Systems, Analytics and Synthesis, Vol. 8, Concepts and Applications of Systemics, Cybernetics and Informatics, 31 July - 4 August 1999 (“the Tehrani Paper”).

The parties agreed that Synthon BV v SmithKline Beecham plc [2006] RPC 10, [2005] UKHL 59, [2006] 1 All ER 685 set out the applicable principles on novelty and Pozzoli Spa v BDMO SA and another [2007] BusLR D117, [2007] EWCA Civ 588, [2007] FSR 37, [2007] Bus LR D117 on obviousness.  The judge considered each item of prior art and concluded that claim1 was anticipated and obvious over Waisel and claim 45 was also obvious over Waisel.  Neither claim was anticipated or obvious over the other prior art.

The arguments on insufficiency were run on squeezes and did not arise.

Conclusion

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