Forman v. Krystal Biotech Inc

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Jonathan Forman (California)
  • Defendant: Krystal Biotech, Inc. (Delaware)
  • Plaintiff's Counsel: Potter Anderson & Corroon LLP
• Case Identification: 1:26-cv-00628, D. Del., 05/29/2026
• Venue Allegations: Venue is alleged to be proper in the District of Delaware as Defendant is a Delaware corporation and therefore resides in the district.
• Core Dispute: Plaintiff alleges he is an omitted inventor on two of Defendant's patents and seeks correction of inventorship under 35 U.S.C. § 256.
• Technical Context: The technology concerns gene therapy for cystic fibrosis using a modified herpes simplex virus (HSV) as a vector to deliver the cystic fibrosis transmembrane conductance regulator (CFTR) gene to a patient's airways.
• Key Procedural History: The complaint alleges that Defendant previously engaged in similar conduct of omitting inventors in a prior case, Periphagen, Inc. v. Krystal Biotech, Inc., which reportedly settled in 2022. It also notes that during prosecution of one of the patents-in-suit, Defendant filed a request to remove one of its own employees, Mr. Krish Krishnan, from the list of named inventors.

Case Timeline

Date	Event
2018-11-01	Meeting between Plaintiff Forman and Defendant's representative, Mr. Krishnan, where Plaintiff allegedly disclosed his invention (approximate date)
2018-11-28	Follow-up communications between Forman and Krishnan
2019-02-08	Priority Date for '529 and '636 Patents (Filing of U.S. Provisional App. No. 62/802,871)
2019-04-01	In-person meeting between Forman and Krishnan in San Francisco (approximate date)
2020-02-07	U.S. Patent Application No. 16/784,599 (leading to '529 patent) filed
2020-09-18	Notice of Allowance issued for application leading to '529 patent
2020-11-06	U.S. Patent Application No. 17/092,119 (leading to '636 patent) filed
2020-11-10	U.S. Patent No. 10,829,529 issued
2022-01-01	Krystal Biotech reportedly settles prior inventorship case, Periphagen, Inc. v. Krystal Biotech, Inc. (approximate year)
2026-01-13	U.S. Patent No. 12,522,636 issued
2026-05-29	Complaint filed

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 10,829,529 - Compositions and Methods for Delivering CFTR Polypeptides (issued Nov. 10, 2020)

The Invention Explained

• Problem Addressed: Cystic fibrosis (CF) is an inherited disease caused by mutations in the CFTR gene, which is critical for lung homeostasis ʼ529 Patent, col. 1:36-41 The resulting buildup of thick mucus leads to airway obstruction, chronic infections, and progressive lung destruction ʼ529 Patent, col. 1:45-51 The complaint adds that a key challenge in developing gene therapy for CF was that the CFTR gene was too large a payload for existing vector technologies like Adeno-Associated Virus (AAV) Compl. ¶19
• The Patented Solution: The invention uses a recombinant herpes virus genome to carry one or more polynucleotides that encode the CFTR polypeptide ʼ529 Patent, col. 2:45-49 This viral vector can then be administered to a subject, for example via a nebulizer, to deliver the functional gene to airway cells and treat the symptoms of the disease ʼ529 Patent, abstract '529 Patent, col. 8:6-9 The patent discloses that these recombinant viruses can successfully express functional human CFTR in cells derived from CF patients ʼ529 Patent, col. 2:8-16
• Technical Importance: Using a herpes virus vector provides a vehicle capable of carrying the large CFTR gene, a payload that was allegedly problematic for prior gene therapy technologies Compl. ¶19

Key Claims at a Glance

• The complaint asserts that Plaintiff conceived of or contributed to the invention claimed in at least claim 1 of the patent Compl. ¶22
• Independent Claim 1 of the '529 patent recites a method with the following essential elements:
  • A method of providing prophylactic, palliative, or therapeutic relief of one or more signs or symptoms of cystic fibrosis in a subject.
  • The method comprises administering an effective amount of a pharmaceutical composition.
  • The composition comprises (a) a herpes virus with a recombinant genome encoding a CFTR polypeptide, and (b) a pharmaceutically acceptable excipient.
  • The CFTR-encoding polynucleotides are operably linked to a promoter.
  • The polynucleotides are expressed to effect a measurable improvement in or prevention of CF symptoms.
  • The pharmaceutical composition is administered to the subject using a nebulizer.
• The complaint does not explicitly reserve the right to assert dependent claims.

U.S. Patent No. 12,522,636 - Compositions and Methods for Delivering CFTR Polypeptides (issued Jan. 13, 2026)

The Invention Explained

• Problem Addressed: As with the parent '529 patent, the technology is directed at treating cystic fibrosis by delivering a functional CFTR gene to airway cells ʼ636 Patent, col. 1:36-54
• The Patented Solution: The patent claims a pharmaceutical composition comprising a specifically engineered, replication-defective herpes simplex virus type 1 (HSV-1) ʼ636 Patent, claim 1 The recombinant HSV-1 genome contains inactivating mutations in the ICP4 and ICP22 genes but not in the ICP27 gene, and is formulated for delivery with a vibrating mesh nebulizer ʼ636 Patent, claim 1 This engineered virus serves as a vehicle to deliver the CFTR-encoding polynucleotide to a subject's airways ʼ636 Patent, col. 2:1-8
• Technical Importance: This patent provides a more specific embodiment of the gene therapy platform, detailing particular genetic modifications to the viral vector (inactivating ICP4 and ICP22) to, for example, reduce toxicity or improve expression, and specifying the delivery device ʼ636 Patent, claim 1

Key Claims at a Glance

• The complaint asserts that Plaintiff conceived of or contributed to the invention claimed in at least claim 1 of the patent Compl. ¶23
• Independent Claim 1 of the '636 patent recites a pharmaceutical composition with the following essential elements:
  • A pharmaceutical composition for delivering polynucleotides encoding a CFTR polypeptide to the airways of a subject.
  • The composition comprises (a) a replication-defective herpes simplex virus type 1 (HSV-1) with a recombinant genome encoding the CFTR polypeptide, and (b) a pharmaceutically acceptable excipient.
  • The composition is formulated in a vibrating mesh nebulizer.
  • The CFTR-encoding polynucleotides are operably linked to a promoter.
  • The recombinant HSV-1 genome has an inactivating mutation in the ICP4 and ICP22 genes.
  • The recombinant HSV-1 genome does not have an inactivating mutation in the ICP27 gene.
• The complaint does not explicitly reserve the right to assert dependent claims.

III. The Accused Instrumentality

Product Identification

• The complaint identifies Krystal Biotech's product KB407 Compl. ¶11

Functionality and Market Context

• KB407 is described as a gene therapy that uses an HSV-1 vector to deliver the cystic fibrosis transmembrane conductance regulator (CFTR) gene to the lungs via a nebulizer Compl. ¶11 The complaint alleges that KB407 is intended for the treatment of cystic fibrosis and is an "embodiment of the '529 patent and the '636 patent" Compl. ¶11 It further alleges that, if approved and marketed, the clinical use of KB407 would be covered by claim 1 of both patents-in-suit Compl. ¶44 Compl. ¶53

No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

The central dispute is not infringement but inventorship. The following tables analyze the core allegations by mapping the elements of the asserted claims to the inventive contributions Plaintiff Jonathan Forman alleges he conceived and disclosed to Defendant.

'529 Patent Inventorship Allegations

Claim Element (from Independent Claim 1)	Plaintiff's Alleged Conception/Contribution	Complaint Citation	Patent Citation
A method of providing prophylactic, palliative, or therapeutic relief of one or more signs or symptoms of cystic fibrosis in a subject in need thereof...	Forman conceived a new use (treatment of cystic fibrosis) for HSV-1 vector technology.	¶18	col. 7:8-14
...comprising administering to the subject an effective amount of a pharmaceutical composition comprising: (a) a herpes virus comprising a recombinant herpes virus genome...	Forman conceived the idea of treating cystic fibrosis by loading the CFTR gene into an HSV-1 vector.	¶20	col. 7:15-21
...wherein the recombinant herpes virus genome comprises one or more polynucleotides encoding a CFTR polypeptide...	Forman conceived of treating cystic fibrosis by loading the CFTR gene into an HSV-1 vector. This addressed the problem that the CFTR gene was too large for existing AAV technologies.	¶19; ¶20	col. 4:63-68
...wherein the pharmaceutical composition is administered to the subject using a nebulizer.	Forman also conceived the idea of using a nebulizer to deliver HSV-1 vector to the lungs of patients with cystic fibrosis.	¶20	col. 8:6-9

'636 Patent Inventorship Allegations

Claim Element (from Independent Claim 1)	Plaintiff's Alleged Conception/Contribution	Complaint Citation	Patent Citation
A pharmaceutical composition useful for delivery of one or more polynucleotides encoding a cystic fibrosis transmembrane conductance regulator (CFTR) polypeptide to the airways of a subject...	Forman conceived a new use (treatment of cystic fibrosis) for HSV-1 vector technology.	¶18	col. 2:1-8
...comprising: (a) a replication defective herpes simplex virus type 1 (HSV-1) comprising a recombinant HSV-1 genome, wherein the recombinant HSV-1 genome comprises the one or more polynucleotides encoding the CFTR polypeptide...	Forman conceived the idea of treating cystic fibrosis by loading the CFTR gene into an HSV-1 vector and administering it via inhalation.	¶20	col. 3:15-19
...wherein the pharmaceutical composition is formulated in a vibrating mesh nebulizer...	Forman conceived the idea of using a nebulizer to deliver the HSV-1 vector to the lungs.	¶20	col. 6:29-32
...wherein the recombinant HSV-1 genome comprises an inactivating mutation in or both copies of the Infected Cell Protein (ICP) 4 herpes simplex virus gene and an inactivating mutation in the ICP22 herpes simplex virus gene...	The complaint alleges Forman conceived the "total inventive concept that is claimed in at least claim 1 of the '636 patent" but does not provide specific facts regarding conception of particular viral gene mutations.	¶57	col. 5:8-12

• Identified Points of Contention:
  • Conception & Contribution: The primary legal question is whether Mr. Forman's alleged disclosures constitute a "definite and permanent idea of the complete and operative invention" sufficient for sole inventorship, or a significant contribution to the conception for joint inventorship Compl. ¶¶2, 49, 58 The complaint alleges Mr. Forman shared his "ideas" about the new use and delivery method at a November 2018 meeting Compl. ¶¶18, 21
  • Corroboration: A key evidentiary issue for the court will be whether Mr. Forman can provide sufficient evidence to corroborate his claim of conception and disclosure. The complaint references "contemporaneous notes" taken by a colleague at the November 2018 meeting and "electronic communications, lab notebooks, notes, and presentations" allegedly in the possession of Krystal Biotech Compl. ¶21 Compl. ¶26
  • Specificity of Contribution: A technical question may arise regarding the specificity of Mr. Forman's alleged contribution relative to the claimed invention. For the '636 patent, which claims specific inactivating mutations in the ICP4 and ICP22 genes, the court may need to determine if Mr. Forman's alleged high-level concept of using an "HSV-1 vector" is a significant enough contribution to the specifically engineered vector that was ultimately claimed (Compl. ¶20; Compl. ¶57; '636 Patent, claim 1).

V. Key Claim Terms for Construction

While claim construction is less central than in an infringement action, the scope of certain terms may be relevant to determining the significance of Mr. Forman's alleged contribution.

• The Term: "nebulizer" ('529 patent, claim 1)

• Context and Importance: The '529 patent claims administration via a generic "nebulizer," while the continuation '636 patent claims formulation in a specific "vibrating mesh nebulizer" ('636 Patent, claim 1). Mr. Forman alleges he conceived of using "a nebulizer" Compl. ¶20 Practitioners may focus on this term because the parties could dispute whether Mr. Forman's alleged general contribution is sufficient to make him an inventor of the more specific invention claimed in the '636 patent.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: The specification of the '529 patent mentions "nebulizers" generally and lists several types, including "vibrating mesh nebulizers," suggesting the term encompasses various devices ʼ529 Patent, col. 6:31-32 '529 Patent, col. 8:8-9
  • Evidence for a Narrower Interpretation: The fact that the applicants pursued a separate patent specifically claiming a "vibrating mesh nebulizer" may suggest that this specific embodiment was considered a distinct inventive concept from the broader genus of nebulizers.

• The Term: "a herpes virus" ('529 patent, claim 1) / "replication defective herpes simplex virus type 1 (HSV-1) ... compris[ing] an inactivating mutation in... ICP4 ... and ... ICP22" ('636 patent, claim 1)

• Context and Importance: Plaintiff alleges he conceived of using "HSV-1 vector technology" Compl. ¶18 The claims, particularly in the '636 patent, recite a specifically engineered HSV-1 vector with mutations in particular genes. The dispute may turn on whether Plaintiff's alleged contribution to using a general HSV-1 platform is significant enough to make him a joint inventor of the specifically claimed, engineered virus.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: The '529 patent broadly describes using a "recombinant herpes virus genome" and lists HSV-1 as one of several possibilities ʼ529 Patent, col. 2:45-49 '529 Patent, col. 3:15-19 This could support the argument that the core concept was the use of the general herpes virus platform.
  • Evidence for a Narrower Interpretation: The specification of the '636 patent details the importance of specific gene deletions, such as in ICP4 and ICP22, for reducing toxicity and enabling expression, which may be presented as the key inventive step beyond merely selecting a viral vector ʼ636 Patent, col. 23:25-56 The prosecution history may reveal arguments made to distinguish the invention over prior art based on these specific mutations.

VI. Other Allegations

• Intentional Omission / Exceptional Case: The complaint alleges that the omission of Mr. Forman as an inventor was not an error but a "strategic move to distance Krystal Biotech from Forman's claims to inventorship" Compl. ¶39 To support this, the complaint alleges a pattern of conduct, citing a prior lawsuit (Periphagen, Inc. v. Krystal Biotech, Inc.) where Defendant allegedly omitted other inventors and subsequently settled for a substantial amount Compl. ¶41 These allegations form the basis for the request that the court declare the case "exceptional" under 35 U.S.C. § 285 and award attorneys' fees Compl., Prayer for Relief (5)

VII. Analyst's Conclusion: Key Questions for the Case

This case is a dispute over inventorship, not infringement. The outcome will likely depend on the resolution of several core factual and legal questions for the court:

• A central issue will be one of conception and contribution: Does Mr. Forman's alleged disclosure of using a nebulized HSV-1 vector to deliver the CFTR gene constitute a complete and definite conception of the inventions claimed in the '529 and '636 patents, or was it, at a minimum, a contribution significant enough to establish joint inventorship?
• A critical evidentiary question will be one of corroboration: Can Mr. Forman produce sufficient, non-self-serving evidence-such as the "contemporaneous notes" from a colleague or internal Defendant documents-to corroborate his testimony regarding the timing, content, and communication of his alleged conception to Krystal Biotech?
• A third question relates to the pattern of conduct: Will the court find the allegations regarding Defendant's conduct in the prior Periphagen litigation relevant to establishing intent or the exceptional nature of the present case, as Plaintiff alleges a strategic pattern of omitting inventors?