---

---

---

•	the accuracy of our estimates regarding expenses, future revenues, uses of cash, capital requirements and the need for additional financing;

•	the initiation, cost, timing, progress and results of our development activities, preclinical studies and clinical trials;

•	the timing of and our ability to obtain and maintain regulatory approval of our existing product candidates, any product candidates that we may develop, and any related restrictions, and/or limitations;

•	our plans to research, develop and commercialize our current and future product candidates and Anticalin platform;

•	our collaborators’ election to pursue or continue research, development and commercialization activities;

•	our ability to obtain future reimbursement and/or milestone payments from our collaborators;

•	our ability to attract collaborators with development, regulatory and commercialization expertise;

•	our ability to obtain and maintain intellectual property protection for our product candidates;

•	our ability to successfully commercialize our product candidates;

•	the size and growth of the markets for our product candidates and our ability to serve those markets;

•	the rate and degree of market acceptance of any future products;

•	the success of competing drugs that are or may become available;

•	regulatory developments in the United States and other countries;

•	the performance of our third-party suppliers and manufacturers and our ability to obtain alternative sources of raw materials;

•	our ability to obtain additional financing;

•	our use of the proceeds from our securities offerings;

•	any restrictions on our ability to use our net operating loss carryforwards; and

•	our ability to attract and retain key personnel.

---

---

---

---

•

Supporting AstraZeneca in the initiation of PRS-060/AZD1402 phase 2 studies. We have reported promising data from our phase 1 SAD study and ongoing MAD study of PRS-060/AZD1402, are completing the ongoing MAD study, and are working with AstraZeneca for drug supply and other preparations for the phase 2a study of PRS-060/AZD1402. We anticipate that AstraZeneca will initiate the study in the second half of this year.

•

Completing PRS-343 through phase 1 dose escalation study and initiating the next phase of development studies in gastric cancer. We presented interim data from the study at a late-breaking presentation at the SITC annual meeting on November 9, 2019. We reported that PRS-343 was well tolerated and had a favorable safety profile at all doses and schedules tested, demonstrated anti-tumor activity in a heavily pre-treated patient population across multiple tumor types and showed a potent increase in CD8+ T-cell numbers in the tumor microenvironment of responders, indicative of 4-1BB agonism on T-cells. Pieris continues to enroll patients in that study at higher dose cohorts and modified dosing schedules and plans to initiate a further trial of the drug candidate in gastric cancer. We also plan to conclude and report complete data from the dose escalation study of PRS-343 in combination with atezolizumab in 2020.

•	Advancing PRS-344 to initiation of a phase 1 study. PRS-344 is currently undergoing IND-enabling activities and we intend to file an IND for the program in the first half of 2020.

•

Continuing to build our platform by entering into new partnerships and license and collaborative arrangements and advancing our currently partnered programs. We have entered into partnership and collaborative arrangements with pharmaceutical companies in a diverse range of therapeutic areas and geographies. We have active strategic partnerships with the global pharmaceutical companies Servier, AstraZeneca and Seattle Genetics. Together with our partners, we intend to advance multiple drug candidates through preclinical studies and to select further drug candidates for clinical development in the future. We will also continue to seek to engage with new pharmaceutical partners that can contribute funding, experience and marketing ability for the successful development and commercialization of our current and future drug candidates.

•	Pursuing additional opportunities for our Anticalin technology. We intend to continue to identify, vet and pursue opportunities to develop novel Anticalin therapeutics for respiratory diseases, oncology and additional diseases.

•

Pursuing other platform development activities. We continue to make investments in our Anticalin platform, including in display and other technologies used to discover and optimize Anticalin proteins against targets of interest to increase the speed, throughput and quality of the selection process. In addition, we continue to make investments in our platform for the characterization and manufacture of Anticalin proteins to develop drug candidates with excellent drug-like properties that can be efficiently produced.

---

•	High specificity to their targets. Like antibodies, Anticalin proteins can bind their targets without binding other molecules, even molecules with very similar chemical structures or amino acid sequences, allowing for more effective treatments through, for example, minimizing off-target effects.

---

•	Tight binding and effective biological activity at their targets. Like antibodies, Anticalin proteins are able to bind their targets at subnanomolar affinities. Anticalin proteins can potentially achieve desirable biological effects by inhibiting an undesired or inducing a desired cell activity by binding to cell-surface receptors or their ligands.

•

Scalability for large-scale production. Like antibodies, Anticalin proteins lend themselves to large-scale production, yet can also be produced in a range of expression systems ranging from prokaryotic (bacterial) to eukaryotic (for example, animal and fungal) cells. Anticalin proteins can take advantage of several well-understood and widely-practiced methods of protein production both in small amounts for preclinical testing and at larger scale for clinical trials and commercial production.

•

Small size and biophysical stability. Anticalin proteins are small in size and are monomeric. Therefore, we believe Anticalin proteins are generally more stable biophysically than antibodies composed of four polypeptide chains, which will potentially enable unique routes of administration, such as pulmonary delivery. Higher-molecular-weight entities such as antibodies are often too large to be formulated and delivered effectively through these methods. We believe Anticalin proteins will also be less expensive to manufacture than antibodies due to their lower molecular weight and less bulky structure as well as the ability to leverage the prokaryotic-based manufacturing systems, a less costly manufacturing system than mammalian cell-based manufacturing systems, to create them.

•

Optimization of half-life. Anticalin proteins can be engineered to have a half-life that is optimal for the indication area and a desired dosing schedule. Antibodies typically have half-lives of two weeks or longer, whereas Anticalin proteins can be engineered to have half-lives from hours to weeks, depending on the half-life extension technology employed, if any. This optionality allows us to exert greater control over the amount of circulating Anticalin protein in the blood and the amount of time such Anticalin proteins circulate in the blood, depending on the underlying biology we are trying to address.

•

Platform for higher-order multispecificity and avoidance of cross-linking. Our Anticalin technology allows for monovalent or multivalent target engagement, including multispecificity within a single protein. We believe that a monovalent “backbone” is an advantage in situations where pure antagonism of certain cellular receptors is desired. The dual-binding nature of antibodies, which have two “arms,” can be a disadvantage in cases when the antibodies bind to and cross-link cell-surface receptors. Such cross-linking often leads to undesirable activation of the cells bearing those receptors. Single-action (monovalent) Anticalin proteins have only a single binding site and by that do not induce cross-linking. Further, when it is called for by the biology we are addressing, we can create multispecific Anticalin proteins that can simultaneously bind (i) two or more different targets or (ii) different epitopes on the same target by genetically linking Anticalin proteins with distinct specificities or by genetic fusion of an Anticalin protein with an antibody. We believe this multispecificity offers advantages in biological settings where binding to multiple targets can enhance the ability of a drug to achieve its desired effects, such as killing cancer cells. Novel Anticalin proteins genetically fused to each other or to existing antibodies for simultaneous target engagement are expressed as a fusion protein without generally compromising on manufacturability.

•

Flexible formatting facilitates selection of potent T-cell engagers. The molecular architecture of Anticalin proteins as a single polypeptide chain that folds into a stable eight-stranded β-barrel with exposed N- and C-termini, both not part of the binding site, makes them ideal building blocks to generate bispecific and even multispecific fusion proteins offering novel therapeutic modalities. Multispecific Anticalin-based fusion proteins can be used to pursue innovative therapeutic strategies in IO, particularly by addressing the “immunological synapse” that forms at the interface upon contact between an immune cell and a cancer cell. This can drive an efficient activation of tumor-specific T-cells in the vicinity of the tumor, thereby avoiding some of the toxicities observed with peripheral T-cell activation in healthy tissues. Generally, the formatting flexibility of Anticalin-based biologics offers the ability of modulating valency and geometry of the multispecific compound according to biological needs. For example, Anticalin proteins can be genetically fused to either the N- or C- terminus of the antibody heavy or light chain, thereby resulting in different geometries of the fusion protein with the antibody as well as Anticalin binding sites covering a range of distances with regard to the T-cell target on the one hand and the tumor antigen on the other.

---

---

---

---

---

---

---

---

---

---

---

•	identifying and validating targets;

•	screening compounds against targets;

---

•	performing preclinical and clinical trials of potential pharmaceutical products; and

•	obtaining regulatory approval.

•	capital resources;

•	research and development resources;

•	manufacturing expertise and capabilities; and

•	sales and marketing capabilities.

---

---

---

---

---

---

---

---

•	completion of preclinical laboratory tests, animal studies and formulation studies according to Good Laboratory Practices regulations or other applicable regulations;

•	submission to the FDA of an IND, which must become effective before human clinical trials may begin;

•	approval by an independent institutional review board, or IRB, or ethics committee at each clinical trial site before each clinical trial may be initiated;

•	performance of adequate and well-controlled human clinical trials in accordance with applicable IND regulations, current good clinical practices, or cGCPs, and other clinical-trial related regulations to evaluate the safety and efficacy of the investigational product for each proposed indication;

•	submission to the FDA of an NDA or BLA for marketing approval, including payment of application user fees;

•	satisfactory completion of an FDA inspection of the manufacturing facility or facilities at which the drug or biologic is produced to assess compliance with cGMP to assure that the facilities, methods and controls are adequate to preserve the product's identity, strength, quality and purity;

•	potential FDA audit of the clinical trial sites to assure compliance with cGCPs and the integrity of the clinical data submitted in support of the NDA or BLA; and

•	FDA review and approval of the NDA or BLA, including satisfactory completion of an FDA advisory committee review of the product candidate, where appropriate or if applicable, prior to any commercial marketing or sale of the product in the United States.

---

•

Phase 1: The product candidate is initially introduced into healthy human subjects and tested for safety, dosage tolerance, absorption, metabolism, distribution and excretion. In the case of some products for severe or life-threatening diseases, such as cancer, especially when the product may be too inherently toxic to ethically administer to healthy volunteers, the initial human testing is often conducted in patients.

•	Phase 2: This phase involves studies in a limited patient population to identify possible adverse effects and safety risks, to preliminarily evaluate the efficacy of the product for specific targeted diseases and to determine dosage tolerance and optimal dosage.

•

Phase 3: Clinical trials are undertaken with an expanded patient population to further evaluate dosage, clinical efficacy and safety in an expanded patient population, often at geographically dispersed clinical study sites. These studies are intended to establish the overall risk-benefit ratio of the product candidate and provide, if appropriate, an adequate basis for product labeling. These trials may include comparisons with placebo and/or other comparator treatments. The duration of treatment is often extended to mimic the actual use of a product during marketing.

---

---

---

---

---

---

•	restrictions on the marketing or manufacturing of the product, complete withdrawal of the product from the market or product recalls;

•	fines, warning letters or other enforcement-related letters or clinical holds on post-approval clinical trials;

•	refusal of the FDA to approve pending NDAs/BLAs or supplements to approved NDAs/BLAs, or suspension or revocation of product approvals;

•	product seizure or detention, or refusal to permit the import or export of products;

•	injunctions or the imposition of civil or criminal penalties; and

•	consent decrees, corporate integrity agreements, debarment, or exclusion from federal health care programs; or mandated modification of promotional materials and labeling and the issuance of corrective information.

---

---

•	Decentralized procedure. Using the decentralized procedure, an applicant may apply for simultaneous authorization in more than one EU country of medicinal products that have not yet been authorized in any EU country and that do not fall within the mandatory scope of the centralized procedure.

•	Mutual recognition procedure. In the mutual recognition procedure, a medicine is first authorized in one EU Member State, in accordance with the national procedures of that country. Following this, further marketing authorizations can be sought from other EU countries in a procedure whereby the countries concerned agree to recognize the validity of the original, national marketing authorization.

---

•	the second applicant can establish that its product, although similar, is safer, more effective or otherwise clinically superior;

•	the applicant consents to a second orphan medicinal product application; or

•	the applicant cannot supply enough orphan medicinal product.

---

•

the federal anti-kickback statute prohibits, among other things, persons from knowingly and willfully soliciting, offering, receiving or paying remuneration, directly or indirectly, in cash or in kind, to induce or reward either the referral of an individual for, or the purchase, order or recommendation of, any good or service, for which payment may be made, in whole or in part, under a federal health care program such as Medicare and Medicaid;

•	the federal False Claims Act imposes civil penalties, and provides for civil whistleblower or qui tam actions, against individuals or entities for knowingly presenting, or causing to be presented, to the federal government, claims for payment that are false or fraudulent or making a false statement to avoid, decrease or conceal an obligation to pay money to the federal government;

•	the federal Health Insurance Portability and Accountability Act of 1996, or HIPAA, imposes criminal and civil liability for executing a scheme to defraud any health care benefit program or making false statements relating to health care matters;

•	HIPAA, as amended by the Health Information Technology for Economic and Clinical Health Act, or HITECH Act, and its implementing regulations, also imposes obligations, including mandatory contractual terms, with respect to safeguarding the privacy, security and transmission of individually identifiable health information;

•

the federal transparency requirements under the Physician Payments Sunshine Act require manufacturers of FDA-approved drugs, devices, biologics and medical supplies covered by Medicare or Medicaid to report, on an annual basis, to the Department of Health and Human Services information related to payments and other transfers of value to physicians, teaching hospitals, and certain advanced non-physician health care practitioners and physician ownership and investment interests;

---

•

the U.S. Foreign Corrupt Practices Act, or FCPA, and other anti-corruption laws and regulations pertaining to our financial relationships and interactions with foreign government officials, which prohibit U.S. companies and their employees, officers, and representatives from paying, offering to pay, promising, or authorizing the payment of anything of value to any foreign government official (including, potentially, healthcare professionals in countries in which we operate or may sell our products), government staff member, political party, or political candidate to obtain or retain business or to otherwise seek favorable treatment; and

•	analogous state and foreign laws and regulations, such as state anti-kickback and false claims laws, may apply to sales or marketing arrangements and claims involving health care items or services reimbursed by nongovernmental third-party payors, including private insurers.

---

---

---

---

•	developing our drug candidates using unproven technologies;

•	undertaking preclinical development and clinical trials as well as formulating and manufacturing products;

•	obtaining the human, financial and other resources necessary to develop, test, manufacture, commercialize and market our drug candidates;

•	engaging corporate partners to assist in developing, testing, manufacturing and marketing our drug candidates;

•	continuing to build and maintain an intellectual property portfolio covering our technology and drug candidates;

•	satisfying the requirements of clinical trial protocols, including patient enrollment, establishing and demonstrating the clinical safety and efficacy of our drug candidates and obtaining necessary regulatory approvals;

•	achieving acceptance and use by the medical community of our Anticalin platform and drug candidates after they receive regulatory approvals;

•	maintaining, growing and managing our internal teams as and to the extent we increase our operations and develop new segments of our business;

•	developing and maintaining successful collaboration, strategic and other relationships for the development and commercialization of our drug candidates that receive regulatory approvals with existing and new partners; and

•	managing our cash flows and any growth we may experience in an environment where costs and expenses relating to clinical trials, regulatory approvals and commercialization continue to increase.

•	fluctuations in foreign currency exchange rates;

•	potentially adverse tax consequences and changes in tax laws;

•	challenges in providing solutions across a significant distance, in different languages and among different cultures;

•	different, complex and changing laws governing intellectual property rights, sometimes affording reduced protection of intellectual property rights in certain countries;

•	difficulties in staffing and managing foreign operations, particularly in new geographic locations, and related compliance with employment, immigration and labor laws for employees or other staff living abroad;

•	restrictions imposed by local labor practices and laws on our business and operations;

---

•	economic weakness, including inflation, or rapid changes in government, economic and political policies and conditions, political or civil unrest or instability, terrorism or epidemics and other similar outbreaks or events;

•	compliance with a wide variety of complex foreign laws, treaties and regulations;

•	compliance with the FCPA and other anti-corruption and anti-bribery laws;

•	unexpected changes in tariffs, trade barriers and other regulatory or contractual limitations on our ability to develop or sell our products in certain foreign markets; and

•	becoming subject to the laws, regulations and court systems of multiple jurisdictions.

---

---

---

---

---

•	developing drugs;

•	undertaking preclinical testing and clinical trials;

•	obtaining FDA and other regulatory approvals of drugs;

•	prosecuting and enforcing intellectual property rights;

•	formulating and manufacturing drugs; and

•	launching, marketing and selling drugs.

---

•	effectively managing our clinical trials and submissions to regulatory authorities for marketing approvals;

•	effectively managing our internal research and development efforts such as discovery research and preclinical development;

•	identifying, recruiting, maintaining, motivating and integrating additional employees;

•	effectively managing our internal and external business development efforts with current or future partners, such as entering into additional collaboration arrangements and increasing out-licensing revenues;

•	establishing relationships with third parties essential to our business and ensuring compliance with our contractual obligations to such third parties;

•	developing and managing new divisions of our internal business, including any sales and marketing segment we elect to establish;

•	maintaining our compliance with public company reporting and other obligations, including establishing and maintaining effective internal control over financial reporting and disclosure controls and procedures; and

•	improving our managerial, development, operational and finance systems.

•	issue common stock or other forms of equity that would dilute our existing stockholders’ percentage of ownership;

•	incur debt and assume liabilities; and

•	incur amortization expenses related to intangible assets or incur large and immediate write-offs.

•	problems integrating the purchased business, products or technologies;

•	challenges in achieving strategic objectives, cost savings and other anticipated benefits;

•	increases to our expenses;

---

•	the assumption of significant liabilities that exceed the limitations of any applicable indemnification provisions or the financial resources of any indemnifying party;

•	inability to maintain relationships with key customers, vendors and other business partners of the acquired businesses;

•	diversion of management’s attention from their day-to-day responsibilities;

•	difficulty in maintaining controls, procedures and policies during the transition and integration;

•	entrance into marketplaces where we have no or limited prior experience and where competitors have stronger marketplace positions;

•	potential loss of key employees, particularly those of the acquired entity; and

•	that historical financial information may not be representative or indicative of our results as a combined company.

---

•	conduct additional preclinical and clinical development with successful outcomes;

•	manage preclinical, manufacturing and clinical activities;

•	obtain regulatory approval from the FDA and other comparable foreign regulatory authorities;

•	establish manufacturing relationships for the clinical and post-approval supply of the applicable drug candidate in compliance with all regulatory requirements;

•	build a commercial sales and marketing team, either internally or by contract with third parties;

•	establish and maintain patent and trade secret protection or regulatory exclusivity for our product candidates;

•	develop and implement marketing strategies for successful commercial launch of our product candidates, if and when approved;

•	secure acceptance of our products, if and when approved, by patients, from the relevant medical communities and from third-party payors;

•	compete effectively with other therapies;

•	establish and maintain adequate health care coverage and reimbursement;

•	ensure continued compliance with any post-marketing requirements imposed by regulatory authorities, including any required post-marketing clinical trials or the elements of any post-marketing Risk Evaluation and Mitigation Strategy, or REMS, that may be required by the FDA or comparable requirements in other jurisdictions to ensure the benefits of the product outweigh its risks;

•	maintain continued acceptable safety profile of the product candidates following approval; and

•	invest significant additional cash in each of the above activities.

---

---

•	delay or failure in reaching agreement with the FDA or a comparable foreign regulatory authority on a trial design that we are able to execute;

•	delay or failure in obtaining authorization to commence a trial, including approval from the appropriate IRB to conduct testing of a candidate on human subjects, or inability to comply with conditions imposed by a regulatory authority regarding the scope or design of a clinical trial;

•	delay in reaching, or failure to reach, agreement on acceptable terms with prospective contract research organizations, or CROs, and clinical trial sites, the terms of which can be subject to extensive negotiation and may vary significantly among different CROs and trial sites;

•	inability, delay or failure in identifying and maintaining a sufficient number of trial sites, many of which may already be engaged in other clinical programs;

•	delay or failure in recruiting and enrolling suitable volunteers or patients to participate in a trial;

•	delay or failure in developing and validating companion diagnostics, if they are deemed necessary, on a timely basis;

•	failure of patients to complete a trial or return for post-treatment follow-up;

•	inability to monitor patients adequately during or after treatment;

•	clinical sites and investigators deviating from trial protocols, failing to conduct the trial in accordance with regulatory requirements or dropping out of a trial;

•	failure to initiate or delay of or inability to complete a clinical trial as a result of a clinical hold imposed by the FDA or comparable foreign regulatory authority due to observed safety findings or other reasons;

•	negative or inconclusive results in our clinical trials, and our decision to or regulators’ requirement that we conduct additional non-clinical studies, clinical trials or that we abandon one or more of our product development programs; or

---

•	inability to manufacture sufficient quantities of a drug candidate of acceptable quality for use in clinical trials.

•	the size and nature of the target patient population;

•	the severity of the disease under investigation;

•	the frequency of the molecular alteration we are seeking to target in the applicable trial;

•	the patient eligibility criteria for the clinical trial in question;

•	our ability to recruit clinical trial investigators with the appropriate competencies and experience;

•	the perceived risks and benefits of the drug candidate under study in the clinical trial;

•	the approval and availability of other therapies to treat the disease or disorder that is being investigated in the clinical trial;

•	the extent of the efforts to facilitate timely enrollment in clinical trials;

•	the patient referral practices of physicians;

---

•	the ability to monitor volunteers or patients adequately during and after treatment;

•	the presence of other drug candidates in clinical development for the same indication or against the same target; and

•	the proximity and availability of clinical trial sites for prospective participants.

---

•	the FDA, EMA or comparable foreign regulatory authorities may disagree with the design or implementation of our clinical trials;

•	we may be unable to demonstrate to the satisfaction of the FDA, EMA or comparable foreign regulatory authorities that a drug candidate is safe and effective for its proposed indication;

•	the results of clinical trials may not meet the level of statistical significance required by the FDA, EMA or comparable foreign regulatory authorities for approval;

•	we may be unable to demonstrate that a drug candidate’s clinical and other benefits outweigh its safety risks;

•	the FDA, EMA or comparable foreign regulatory authorities may disagree with our interpretation of data from preclinical studies or clinical trials;

•	the data collected from clinical trials of our drug candidates may not be sufficient to support the submission of a BLA or other submission or to obtain regulatory approval in the United States or elsewhere;

•	upon review of our clinical trial sites and data, the FDA or comparable foreign regulatory authorities may find our record keeping or the record keeping of our clinical trial sites to be inadequate;

•	the manufacturing processes or facilities of third-party manufacturers with which we contract for clinical and commercial supplies may fail to meet the requirements of the FDA, EMA or comparable foreign regulatory authorities;

•	the FDA, EMA or comparable foreign regulatory authorities may fail to approve the companion diagnostics we contemplate developing internally or with partners; and

•	the change of the medical standard of care or the approval policies or regulations of the FDA, EMA or comparable foreign regulatory authorities may significantly change in a manner that renders our clinical data insufficient for approval.

---

•	regulatory authorities may withdraw or limit their approval of such product candidates;

•	regulatory authorities may require the addition of labeling statements, specific warnings or a contraindication;

•	we may be required to create a medication guide outlining the risks of such side effects for distribution to patients, or we may be required to implement a REMS to ensure that the benefits of the product outweigh the risks;

•	we may be required to change the way such product candidates are distributed or administered, or change the labeling of the product candidates;

•	we may be subject to regulatory investigations and government enforcement actions;

•	the FDA or a comparable foreign regulatory authority may require us to conduct additional clinical trials or costly post-marketing testing and surveillance to monitor the safety and efficacy of the product;

---

•	we may decide to recall such product candidates from the marketplace after they are approved;

•	we could be sued and held liable for injury caused to individuals exposed to or taking our product candidates; and

•	our reputation may suffer.

---

•	We may be unable to identify manufacturers on acceptable terms, or at all, because the number of qualified potential manufacturers is limited. Following BLA approval, if successful, a change in the manufacturing site could require additional approval from the FDA. This approval would require new testing and compliance inspections.

•	Our third-party manufacturers might be unable to formulate and manufacture our drugs in the volume and of the quality required to meet our clinical and commercial needs, if any.

•	Our future CMOs may not perform as contractually agreed or may not remain in the contract manufacturing business for the time required to supply our clinical trials or to successfully produce, store and distribute our products.

•	Drug manufacturers are subject to ongoing periodic unannounced inspection by the FDA, and some state agencies to ensure strict compliance with cGMP regulations and other U.S. and corresponding foreign requirements. We do not have control over third-party manufacturers’ compliance with these regulations and standards.

•	If any third-party manufacturer makes improvements in the manufacturing process for our products, we may not own, or may have to share, the intellectual property rights to the innovation.

---

---

•	our collaborators may develop and commercialize, either alone or with others, products that are similar to or competitive with the products that are the subject of the collaboration with us;

•	our collaborators may underfund, not commit sufficient resources to, or conduct in an unsatisfactory manner the development, testing, marketing, distribution or sale of our drug candidates;

•	our collaborators may not properly maintain or defend our intellectual property rights or utilize our proprietary information in such a way as to invite litigation that could jeopardize or potentially invalidate our intellectual property or proprietary information or expose us to potential liability;

•

our collaborators may encounter conflicts of interest, changes in business strategy or other business issues that could adversely affect their willingness or ability to fulfill their obligations to us (for example, pharmaceutical and biotechnology companies historically have re-evaluated their priorities following mergers and consolidations, which have been common in recent years in these industries);

•	disputes may arise between us and our collaborators delaying or terminating the research, development, manufacture or commercialization of our drug candidates, resulting in significant litigation or arbitration that could be time-consuming and expensive, or causing collaborators to act in their own self-interest and not in the interest of our stockholders;

•	we might not have the financial or human resources to meet our obligations or take advantage of our rights under the terms of our existing and future collaborations; and

•	our existing collaborators may exercise their respective rights to terminate their collaborations with us without cause, in which event, we might not be able to complete development and commercialization of our drug candidates on our own.

---

•	restrictions on the manufacturing of the product, the approved manufacturers or the manufacturing process;

•	restrictions on the labeling or marketing of a product;

•	restrictions on product distribution or use;

•	requirements to conduct post-marketing studies or clinical trials;

•	withdrawal of the product from the market;

•	product recalls;

•	warning or untitled letters from the FDA or comparable notice of violations from foreign regulatory authorities;

•	refusal of the FDA or other applicable regulatory authority to approve pending applications or supplements to approved applications;

---

•	fines, restitution or disgorgement of profits or revenues;

•	suspension or withdrawal of marketing approvals;

•	suspension of any of our ongoing clinical trials;

•	product seizure or detention or refusal to permit the import or export of products; and

•	consent decrees, injunctions or the imposition of civil or criminal penalties.

•	the efficacy and potential advantages compared to alternative treatments or competitive products;

•	perceptions by the medical community, physicians, and patients, regarding the safety and effectiveness of our products and the willingness of the target patient population to try new therapies and of physicians to prescribe these therapies;

•	the size of the market for such drug candidate, based on the size of the patient subsets that we are targeting, in the territories for which we gain regulatory approval and have commercial rights;

•	the safety of the drug candidate as demonstrated through broad commercial distribution;

•	the ability to offer our product candidates for sale at competitive prices;

•	the availability of adequate reimbursement and pricing for our products from governmental health programs and other third-party payors;

•	relative convenience and ease of administration compared to alternative treatments;

•	cost-effectiveness of our product relative to competing products;

•	the prevalence and severity of any side effects;

•	the adequacy of supply of our product candidates;

•	the timing of any such marketing approval in relation to other product approvals;

---

•	any restrictions on concomitant use of other medications;

•	support from patient advocacy groups; and

•	the effectiveness of sales, marketing and distribution efforts by us and our licensees and distributors, if any.

---

---

---

•	reduced resources of our management to pursue our business strategy;

•	decreased demand for any products that we may develop;

•	injury to our reputation and significant negative media attention;

•	withdrawal of clinical trial participants or sites;

•	significant costs to defend the related litigation;

•	substantial monetary awards to clinical trial participants or patients;

•	loss of revenue;

•	increased insurance costs; and

•	the inability to commercialize any products that we may develop.

---

•

the U.S. federal Anti-Kickback Statute, which prohibits, among other things, persons from knowingly and willfully soliciting, offering, receiving or providing remuneration, directly or indirectly, in cash or in kind, to induce or reward, or in return for, either the referral of an individual for, or the purchase, order or recommendation of, any good or service, for which payment may be made under a federal health care program such as Medicare and Medicaid; a person or entity does not need to have actual knowledge of the statute or specific intent to violate it in order to have committed a violation;

•

U.S. federal false claims, false statements and civil monetary penalties laws, including the U.S. False Claims Act, which impose criminal and civil penalties against individuals or entities for knowingly presenting, or causing to be presented, to the federal government, claims for payment that are false or fraudulent or making a false statement to avoid, decrease or conceal an obligation to pay money to the federal government; actions may be brought by the government or a whistleblower and may include an assertion that a claim for payment by federal health care programs for items and services which results from a violation of the federal Anti-Kickback Statue constitutes a false or fraudulent claim for purposes of the False Claims Act;

•

the U.S. Health Insurance Portability and Accountability Act of 1996, or HIPAA, that imposes criminal and civil liability for executing a scheme to defraud any health care benefit program, or knowingly and willfully falsifying, concealing or covering up a material fact or making any materially false statement in connection with the delivery of or payment for health care benefits, items or services; similar to the U.S. federal Anti-Kickback Statute, a person or entity does not need to have actual knowledge of the statute or specific intent to violate it in order to have committed a violation;

•	analogous state and foreign laws and regulations relating to health care fraud and abuse, such as state anti-kickback and false claims laws, that may apply to sales or marketing arrangements and claims involving health care items or services reimbursed by non-governmental third-party payors, including private insurers;

•	the FCPA and other anti-corruption laws and regulations pertaining to our financial relationships and interactions with foreign government officials;

•

the U.S. federal physician payment transparency requirements, sometimes referred to as the “Sunshine Act,” which requires manufacturers of drugs, devices, biologics and medical supplies that are reimbursable under Medicare, Medicaid, or the Children’s Health Insurance Program to report to the Centers for Medicare & Medicaid Services, or CMS, information related to physician payments and other transfers of value to physicians and teaching hospitals (and, beginning in 2021, for transfers of value to other health care providers), as well as the ownership and investment interests of physicians and their immediate family members;

•

analogous state and foreign laws that require pharmaceutical companies to track, report and disclose to the government and/or the public information related to payments, gifts, and other transfers of value or remuneration to physicians and other health care providers, marketing activities or expenditures, or product pricing or transparency information, or that require pharmaceutical companies to implement compliance programs that meet certain standards or to restrict or limit interactions between pharmaceutical manufacturers and members of the health care industry;

•	the U.S. federal laws that require pharmaceutical manufacturers to report certain calculated product prices to the government or provide certain discounts or rebates to government authorities or private entities, often as a condition of reimbursement under federal health care programs;

•

HIPAA, which imposes obligations on certain covered entity health care providers, health plans, and health care clearinghouses as well as their business associates that perform certain services involving the use or disclosure of individually identifiable health information, including mandatory contractual terms, with respect to safeguarding the privacy, security and transmission of individually identifiable health information; and

•	state and foreign laws that govern the privacy and security of health information in certain circumstances, including state security breach notification laws, state health information privacy laws and federal and state consumer protection laws, many of which differ from each other in significant ways and often are not preempted by HIPAA, thus complicating compliance efforts.

---

---

•	the degree and range of protection any patents will afford us against competitors, including whether third parties will find ways to make, use, sell, offer to sell or import competitive products without infringing our patents;

•	if and when patents will be issued;

•	how laws in the various jurisdictions, such as the USPTO or the European Patent Office, or the EPO, will change thus affecting our ability to obtain patents or maintain and enforce existing patents;

•	whether or not others will obtain patents claiming inventions similar to those covered by our patents and patent applications; or

•	whether we will need to initiate litigation or administrative proceedings (for example, at the USPTO or the EPO) in connection with patent rights, which may be costly whether we win or lose.

---

---

---

---

•	the employer must observe the applicable notice period, which is ordinarily determined by law (between four weeks and seven months, depending upon the length of employment), if a longer period is not otherwise agreed by the parties, and has to deliver a written notice of termination to the employee;

•

for companies with more than 10 employees, the German Termination Protection Act generally restricts termination of employment if the employee has been employed for more than six months, wherein the employee may be terminated only for a particular reason, including certain behavioral or personal reasons relating to the employee or certain developments relating to the business of the employer, such as a business restructuring which reduces the number of employee positions;

•

special termination protection against unlawful dismissal applies to several other groups of employees, such as an employee that is an officially acknowledged handicapped person, an employee who was appointed as a company’s data protection officer or as a member of the works council of a company, if any, an employee on three years’ maternity leave or a pregnant employee (in these cases, approval of various German authorities is required prior to termination but usually very difficult to obtain); and

---

•	if a company engages in a mass layoff, which is deemed to occur when the employer intends to dismiss a large percentage of its employees during a one-month period, prior written notification to the German employment office is required.

---

•	the drug candidates we seek to pursue, and our ability to obtain rights to develop, commercialize and market those drug candidates;

•	our decision to initiate a clinical trial, not to initiate a clinical trial or to terminate an existing clinical trial;

•	actual or anticipated adverse results or delays in our clinical trials;

•	our failure to commercialize our drug candidates, if approved;

•	unanticipated serious safety concerns related to the use of any of our drug candidates;

•	adverse regulatory decisions;

•	additions or departures of key scientific or management personnel;

•	changes in laws or regulations applicable to our drug candidates, including without limitation clinical trial requirements for approvals;

•	the perception of the pharmaceutical and biotechnology industry by the public, legislatures, regulators and the investment community;

•	disputes or other developments relating to patents and other proprietary rights and our ability to obtain patent protection for our drug candidates;

•	significant lawsuits, including patent and stockholder class action litigation;

•	our dependence on third parties, including CROs and CMOs as well as our current and potential partners that produce companion diagnostic products;

•	failure to meet or exceed any financial guidance or expectations regarding development milestones that we may provide to the public;

•	actual or anticipated variations in quarterly operating results;

•	failure to meet or exceed the estimates and projections of the investment community;

•	overall performance of the equity markets and other factors that may be unrelated to our operating performance or the operating performance of our competitors, including changes in market valuations of similar companies;

•	conditions or trends in the biotechnology and biopharmaceutical industries;

•	introduction of new products by us or our competitors;

•	announcements of significant acquisitions, strategic partnerships, joint ventures or capital commitments by us or our competitors;

•	our ability to maintain an adequate rate of growth and manage such growth;

•	issuances of debt or equity securities;

•	sales of our common stock by us or our stockholders in the future, or the perception that such sales could occur;

---

•	trading volume of our common stock;

•	ineffectiveness of our internal control over financial reporting or disclosure controls and procedures;

•	general political and economic conditions;

•	effects of natural or man-made catastrophic events; and

•	other events or factors, many of which are beyond our control.

---

---

---

•	a classified Board of Directors with staggered three-year terms;

•	the ability of our Board of Directors to issue one or more series of preferred stock with voting or other rights or preferences that could have the effect of impeding the success of an attempt to acquire us or otherwise effect a change of control;

•	advance notice for nominations of directors by stockholders and for stockholders to include matters to be considered at stockholder meetings;

•	certain limitations on convening special stockholder meetings and the prohibition of stockholder action by written consent; and

•	directors may only be removed for cause and only by the affirmative vote of the holders of at least 80% of the voting power of all of the then-outstanding shares of our capital stock entitled to vote at an election of directors, voting together as a single class.

---

•	adversely affect the voting power of the holders of our common stock;

•	make it more difficult for a third party to gain control of us;

•	discourage bids for our common stock at a premium;

•	limit or eliminate any payments that the holders of our common stock could expect to receive upon our liquidation; or

•	otherwise adversely affect the market price or our common stock.

---

---

---

•

PRS-060/AZD1402, our lead respiratory program partnered with AstraZeneca, a drug candidate that antagonizes IL-4Rα, thereby inhibiting IL-4 and IL-13, two cytokines known to be key mediators in the inflammatory cascade that drive the pathogenesis of asthma and other inflammatory diseases. We are sponsoring the phase 1 studies of PRS-060/AZD1402 with and AstraZeneca is funding the costs. AstraZeneca will conduct and fund the phase 2a study of the drug candidate, after which we will have separate options to co-develop and co-commercialize PRS-060/AZD1402 in the United States.

---

•

We are developing additional respiratory drug candidates beyond PRS-060/AZD1402, within and outside of the AstraZeneca alliance. We have initiated three discovery-stage respiratory programs in our alliance with AstraZeneca, the targets and disease areas for which are undisclosed. AstraZeneca may initiate one additional program within the alliance, for a total of four programs beyond PRS-060/AZD1402. We retain co-development and co-commercialization rights to two out of the four programs beyond PRS-060/AZ1402. We also continue to advance several discovery-stage respiratory programs outside of the AstraZeneca collaboration.

•	PRS-343, our lead IO program, is a fusion protein, comprising a HER2-targeting antibody genetically linked to 4-1BB-targeting Anticalin proteins. PRS-343 is designed to drive tumor localized T-cell activation through tumor-targeted drug clustering mediated by HER2 expressed on tumor cells. This program was the first bispecific T-cell co-stimulatory agonist to enter clinical development.

•

We are also developing additional IO drug candidates that are multispecific Anticalin-based fusion proteins designed to engage immunomodulatory targets, comprising a variety of multifunctional biotherapeutics, including PRS-344, a bispecific antibody-Anticalin fusion protein comprising an PD-L1-targeting antibody genetically fused to Anticalin proteins specific for 4-1BB. PRS-344 is being developed as part of our IO collaboration with Servier.

•

PRS-060/AZD1402 was tested in a nebulized formulation in 54 healthy volunteers at nominal dose levels ranging from 0.25 mg to 400 mg in a phase 1 SAD study. Data from that study were presented at the American Thoracic Society International Conference in May 2019 showing that PRS-060/AZD1402 was well tolerated when given as a single inhaled or intravenous doses to healthy volunteers and there was systemic target engagement (as measured by pSTAT6 inhibition). We presented interim data from the ongoing PRS-060/AZD1402 phase 1 MAD study at the European Respiratory Society International Congress in October 2019 and reported that PRS-060/AZD1402 was safe and well-tolerated at all doses, led to a statistically significant reduction in FeNO, a validated biomarker for eosinophilic airway inflammation, and showed dose-dependent systemic target engagement in patients with mild asthma and elevated levels of FeNO (≥ 35ppb). In that study, during the treatment period, 30 patients were randomized to receive delivered doses of PRS-060/AZD1402 ranging from 2 mg to 60 mg (5 mg to 150 mg administered through a nebulizer (nominal dose)) twice daily for nine consecutive days and one final dose on the 10th day, and 12 patients were randomized to receive placebo at the same intervals. Statistically significant and pronounced inhibition of FeNO relative to placebo was observed at all doses. When comparing the 20 mg PRS-060/AZD1402 powered cohort (n=12) to placebo, the primary statistical analysis using the emax model demonstrated a 36% relative reduction in FeNO (p-value <0.0001). Systemic target engagement was dose-dependent and closely aligned with systemic exposure of the drug, consistent with results of the phase 1 SAD study. No systemic target engagement and minimal systemic exposure was observed at the 2 mg dose, suggesting that local target engagement by the drug may be sufficient to reduce airway inflammation, as evidenced by FeNO reduction at that 2 mg dose level. Following these reported results, we and AstraZeneca are preparing to move into a phase 2a study in moderate-to-severe asthmatics in the second half of 2020.

•

We presented interim data from our phase 1 dose escalation study at the SITC annual meeting on November 9, 2019. We reported that PRS-343 was well tolerated and had a favorable safety profile at all doses and schedules tested, demonstrated anti-tumor activity in a heavily pre-treated patient population across multiple tumor types and showed a potent increase in CD8+ T-cell numbers in the tumor microenvironment of responders, indicative of 4-1BB agonism on T-cells. Pieris continues to enroll patients in that study at higher dose cohorts and plans to initiate the next stage of clinical development in gastric cancer this year. We also continue to enroll the dose-escalation phase 1 study of PRS-343 in combination with atezolizumab and reported initial data from the study at our R&D day on November 19, 2019 in New York.

•

For our other IO drug candidates and programs, we are conducting activities relating to candidate identification, optimization and preclinical evaluation. We achieved two preclinical milestones in connection with the PRS-344 program, one in December 2018 and another in February 2019, triggering two milestone payments from Servier, and intend to file an IND for the drug candidate in the first half of 2020. We also executed our option to opt-into co-development and United States commercialization of PRS-344 during the first quarter of 2019. In September 2019, Servier notified us of its decision to discontinue co-development of PRS-332, a PD-1-LAG-3 bispecific for strategic reasons. We do not presently intend to continue development of PRS-332 but retain full rights to advance the development and commercialization of the product on a world-wide basis. Servier’s termination of the co-development of the PRS-332 program does not impact the remainder of the Pieris-Servier alliance and the parties continue to advance PRS-344 through IND-enabling activities. The Pieris-Servier alliance includes three additional programs beyond PRS-344, all of which are in active preclinical development.

---

•	internal recurring costs, such as personnel-related costs (salaries, employee benefits, equity compensation, and other costs), materials and supplies, facilities and maintenance costs attributable to research and development functions; and

•	fees paid to external parties who provide us with contract services, such as preclinical testing, manufacturing and related testing, and clinical trial activities.

---

•

The $16.4 million increase in revenue from contracts with customers for the year ended December 31, 2019 compared to the year ended December 31, 2018 primarily relates to higher amounts of Servier revenue recorded upon termination of the co-development of PRS-332 by Servier for strategic reasons, higher revenue for AstraZeneca due to the termination of certain performance obligations determined at the origination of the agreement, and recognition of previously-deferred revenue for ASKA upon delivery of the final clinical report. These increases were partially offset by lower activity levels with respect to our collaboration agreement with Seattle Genetics and revenue recognized upon termination of our agreement with Roche in 2018.

•	The $0.9 million increase in collaboration revenues in the year ended December 31, 2019 compared to the year ended December 31, 2018 relates to increased research and development activities under our collaboration with Servier.

---

•	the $6.0 million increase in our immuno-oncology program spending period-over-period is due primarily to an increase in clinical trials costs incurred for PRS-343 and drug product manufacturing for PRS-343, PRS-344 and other proprietary programs;

•

the $3.0 million increase for our respiratory programs period-over-period is due primarily to increases to our ongoing CMC costs incurred for phase 2a readiness for PRS-060/AZD1402 offset by slightly lower clinical costs as the phase 1 SAD study that was completed earlier in 2019. We also incurred higher pre-clinical and lab supply expenses as we initiated and were working on more proprietary and partnered respiratory programs in 2019 as compared to 2018;

•	the $1.5 million decrease for our anemia program, PRS-080, period-over-period is mainly due to lower clinical costs as the phase 2a study ended in 2019 compared to being active during the same period in 2018; and

•	the $6.0 million increase in other research and development activities expenses is mainly due to higher personnel expenses, including bonus and stock compensation, due to an overall increase in headcount; an increase in recruiting costs; and an increase in allocated facility costs due to higher non-cash rent charges for the new Hallbergmoos facility that we took occupancy of in February 2020.

---

•	the scope, rate of progress, results and cost of our clinical studies, preclinical testing and other related activities;

•	the cost of manufacturing clinical supplies, and establishing commercial supplies, of our drug candidates and any products that we may develop;

•	the number and characteristics of drug candidates that we pursue;

---

•	the cost, timing and outcomes of regulatory approvals;

•	the cost and timing of establishing sales, marketing and distribution capabilities;

•	the terms and timing of any collaborative, licensing and other arrangements that we may establish;

•	the timing, receipt and amount of sales, profit sharing or royalties, if any, from our potential products;

•	the cost of preparing, filing, prosecuting, defending and enforcing any patent claims and other intellectual property rights; and

•	the extent to which we acquire or invest in businesses, products or technologies, although we currently have no commitments or agreements relating to any of these types of transactions.

---

---

---

---

---

---

•	Developed and documented formal policies regarding the income tax provision process, including the identification of key controls and necessary steps by which management can evaluate the use of third party specialists.

•	Developed and utilized a detailed checklist to identify significant transactions and/or events that may require further evaluation by tax advisors or tax specialists as part of the quarterly and annual tax provision process.

•	Ensured that management's oversight of external advisors was appropriate, including that adequate resources were available and that sufficient preparation and review activities occurred when calculating the quarterly and annual tax provision. This included the ability to engage and involve certain tax specialists to assist in the assessment and evaluation of certain tax matters, as needed.

•	Prepared documentation that was sufficiently reviewed by our external tax advisors and by finance management that addressed all significant tax matters identified for each reporting period.

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

•	Level 1 inputs are quoted prices in active markets for identical assets or liabilities that the reporting entity has the ability to access at the measurement date.

•	Level 2 utilizes quoted market prices in markets that are not active, broker or dealer quotations, or alternative pricing sources with reasonable levels of price transparency.

•	Level 3 inputs are unobservable inputs for the asset or liability in which there is little, if any, market activity for the asset or liability at the measurement date.

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

---

•	senior to all of the Company's common stock;

•	senior to any class or series of capital stock of the Company created after the designation of the Series B Preferred Stock specifically ranking by its terms junior to the Series B Preferred Stock, or the Junior Securities;

---

•	on parity with all shares of Series A Preferred Stock and any class or series of capital stock of the Company created after the designation of the Series B Preferred Stock specifically ranking by its terms on parity with the Series B Preferred Stock, or the Parity Securities; and

•	junior to any class or series of capital stock of the Company created after the designation of the Series B Preferred Stock specifically ranking by its terms senior to the Series B Preferred Stock, or the Senior Securities;

---

---

---

---