Exhibit 10.28

August 24, 2015

AS AMENDED

Dear Cara:

We are pleased to present an offer of employment with ContraFect Corporation (hereinafter the “Company”). The general terms of this offer are as follows:

You are being hired into the position of Chief Medical Officer, reporting to the Company’s Chief Executive Officer. Your starting date is expected to be on or about September 25, 2015; duties and responsibilities have been/will be described to you, and may change from time to time at the discretion of management.

Your base salary will be at the annualized rate of $390,000.00, less all applicable taxes and withholdings, to be paid in accordance with the Company’s regular payroll practices (currently semi-monthly pay periods). Such base salary may be adjusted from time to time in accordance with normal business practices and in the sole discretion of the Company. In this position, you will be an exempt employee, meaning that you will not be entitled to overtime pay.

You will be eligible for an annual incentive bonus of 40% of your annual base salary based upon mutually agreed-upon goals (70% corporate/30% individual).

You will be granted incentive stock options to purchase an aggregate number of 250,000 shares of ContraFect common stock, subject to the terms of ContraFect Corporation’s 2014 Omnibus Incentive Plan in two tranches: 150,000 upon hire, and, assuming that you remain an employee in good standing at that time, an additional 100,000 options above and beyond the anticipated annual incentive grants in January 2016. Your initial grant will vest ratably over a three-year period (25% upon issuance and 25% at each yearly anniversary.) Your grants in January 2016 will vest according to our regular vesting schedule, currently 6.25% per quarter. All stock option grants will be priced after you join the Company, on the dates that the Compensation Committee approves the respective grants.

You will receive a signing bonus of $25,000, less all applicable taxes and withholdings, within 45 days of your date of hire. This signing bonus must be repaid in full should you resign without Good Reason, as defined below, or are terminated for Cause during your first year of employment. For purposes of this paragraph Cause is defined as: (i) the commission of an act of

embezzlement, fraud, theft, misappropriation of assets or property (tangible or intangible) of the Company; (ii) gross negligence or misconduct in the performance of your duties; or (iii) the conviction of a felony, or any crime involving moral turpitude.

In the event that you are terminated by the Company without Cause, or in the event that you resign with Good Reason, as defined below, you will be given (i) a severance payment in the amount that is equal to twelve (12) months of your then-current base salary, (ii) a payment equal to your accrued bonuses and (iii) a payment equal to twelve (12) months of applicable health insurance premiums (inclusive of dental and vision insurance) due under COBRA, provided that you first sign a Severance and Release Agreement in a form prescribed by the Company. These severance payments shall be paid over twelve (12) months as any regular paycheck.

Good Reason shall mean the occurrence of any of the events or conditions as described here: (i) a material diminution of your title or who you report to; (ii) a material reduction in your then-effective base salary, or (iii) the relocation of your principal place of employment to a location that is more than fifty (50) miles “as the crow flies” from Yonkers, New York.

If there is a Change of Control Event and, within twelve (12) months of such Change of Control Event, you resign for Good Reason or you are terminated without Cause, you will receive the severance benefits as outlined above, and, in addition, your then-outstanding stock options and other equity awards, if any, will become immediately fully vested and exercisable. All such benefits are conditioned upon the execution of a Severance and Release Agreement in a form prescribed by the Company or its successors.

A “Change of Control Event” means any of the following: (i) any person or entity (except for a current stockholder) becomes the beneficial owner of greater than 50% of the then-outstanding voting power of the Company; (ii) a merger or consolidation with another entity where the voting securities of the Company outstanding immediately before the transaction constitute less than a majority of the voting power of the voting securities of the surviving entity outstanding immediately after the transaction, or (iii) the sale or disposition of all or substantially all of the Company’s assets.

As a full-time employee, you will be eligible for standard Company benefits, including medical benefits, paid holidays, paid sick/personal days and paid vacation. These are each described in the Employee Handbook.

This offer is expressly conditioned on the following:

Your acceptance of this offer shall also mean that you agree to, at all times, abide by the Company’s policies and procedures.

Please confirm your acceptance of this offer by signing below. You further acknowledge by signing below that with this Offer Letter you received the Confidential Information and Inventions Assignment Agreement referred to above.

We are delighted to invite you to join ContraFect. It is an exciting time in our Company’s history as the U.S. Food and Drug Administration (FDA) has granted Fast Track designation to CF-301, the first lysin in a new class of medicines, currently in a Phase 1 Clinical Trial, for the treatment of Staph aureus bloodstream infections, including MRSA. We are using ContraFect’s technical expertise to develop biotherapeutic products for infectious diseases that have high rates of unmet medical needs, particularly products used in hospital-based markets. We are confident that you will play an important role in the growth and success of the Company.

Sincerely,

Julia P. Gregory

Chief Executive Officer

ACKNOWLEGED, ACCEPTED and AGREED: